Sustainable Poultry Feeding Strategies for Achieving Zero Hunger and Enhancing Food Quality

1. Introduction

The current global challenge of achieving food security and ensuring access to sufficient, nutritious, and safe food for all while maintaining or improving agricultural sustainability has been presented in the United Nations’ Sustainable Development Goals (SDGs), particularly Goal 2, which refers to Zero Hunger. This goal emphasizes the necessity to end hunger while achieving food security through improved nutrition and promote sustainable agricultural practices by 2030.

In the agricultural sector, poultry production plays an important role in the global food system, providing consumers with a major source of high-quality animal protein through meat and eggs [1]. However, since conventional poultry feed raw materials, mainly corn and soybean meal, this poses challenges with respect to its sustainability, such as deforestation, biodiversity loss, and more greenhouse gases associated with their manufacture and transportation [2]. In this context, new strategies are needed to develop and implement alternative feeding strategies for poultry. In recent years, there has been a growing interest in the potential of alternative feed ingredients as viable and practical alternatives to conventional poultry diets. These alternatives not only aim to reduce the ecological footprint of poultry farming but also are great candidates to enhance the nutritional profile of poultry products and performances. The utilization of diverse novel and alternative feed ingredients, such as legume waste [3], oilseed meals [4,5], fruit waste [6,7], leaves or plants [8,9], and other agricultural by-/co-products [10], into poultry diets offers promising ways to mitigate the current challenges in poultry industries. Nevertheless, the transition to alternative feed ingredients for poultry is complex, and the nutritional adequacy, feed palatability, cost-effectiveness, and supply chain logistics should be considered. For example, understanding the nutritional requirements of poultry and the nutrient composition of various feed ingredients is crucial for formulating balanced diets that support optimal growth, health, productivity, and product quality. Moreover, the variability in nutrient content and the presence of anti-nutritional factors in some alternative ingredients require careful laboratory assessments and processing to ensure their effective utilization in poultry diets [11]. However, numerous research studies dealing with feed technology and animal nutrition science have facilitated the development of novel feed formulations that incorporate alternative ingredients without compromising poultry performance while improving poultry product quality, as further presented in the current paper.

In this context, this review paper aims to explore potential alternative and sustainable poultry feeding strategies that align with the Sustainable Development Goal of Zero Hunger (SDG 2). The paper examines the chemical composition, and bioactive compounds present in the alternative feed ingredient options and their potential to enhance poultry production performances, health, and food quality while contributing to a circular economy (Figure 1).

Figure 1. Overview of potential valorisation of co-/by-products and agro-food industry waste in poultry to achieve Zero Hunger.

2. SDG 2: Zero Hunger and the Role of Poultry Production in Global Food Security and the Circular Economy

2.1. SDG 2: Zero Hunger and Why It Is Relevant to Poultry Production

Zero Hunger is one of the 17 SDGs established by the United Nations in 2015 as part of the 2030 Agenda for Sustainable Development, officially known as SDG 2 [12]. This goal, as described in the agenda, addresses a range of interconnected issues related to hunger, food quality, and food security. The main goal is to ensure that all people, especially poor and vulnerable populations, have access to sufficient, nutritious, and safe food products all year round. This involves not only increasing animal-origin food production but also improving food system distribution and reducing food waste [13]. A potential strategy to achieve sustainable nutrition and health for the increasing population can be formulated by following the principles of bioeconomy, which involves the production of renewable biological resources and the conversion of these resources and waste streams into valueadded products, such as food, feed, bio-based products, and bioenergy [14]. Furthermore, to increase the eco-sustainability of the food processing industry, food waste, by-products, co-products, and/or plants should be exploited before they become waste or neglected. Dealing with food waste is of great importance, especially in terms of combating hunger, raising incomes, and improving food security in the poorest countries. Until a few decades ago, food waste was not considered either a cost nor a benefit. However, to maximize benefits for the environment, society, and economy, the FAO is currently developing a code of conduct (CoC) for the reduction of food loss and waste and has proposed an inverted pyramid, setting priorities on how to best reduce food waste and save natural resources [15]. To achieve this target, SDG 2 emphasizes the importance of sustainable agriculture, which involves promoting agricultural practices that increase productivity and production, among other objectives.

2.2. Poultry Production as a Pillar of Food Security

Poultry production plays a pivotal role in providing affordable, high-quality protein to millions of consumers globally, contributing directly to SDG 2 by enhancing food security and promoting sustainable agricultural practices [16].

From a nutritional point of view, poultry products (chicken meat and eggs) are among the most consumed animal-origin-derived products worldwide, being rich sources of protein, amino acids, fats, vitamins, and minerals, which are crucial for various bodily functions, including immune system support and cognitive development essential for human health, particularly in developing countries [17]. Furthermore, poultry meat generally contains lower levels of saturated fats compared to red meats [18], making it a healthier option for consumers and supporting efforts to reduce diet-related non-communicable diseases.

From an economic point of view, due to efficient feed conversion and short production cycles, poultry production is cost-effective, making poultry products more affordable compared to other animal protein sources [19], which increases their accessibility to a larger population, including low-income families. Eggs and chicken meat products are often included in school feeding programs, pregnant women, and emergency food aid due to their high nutritional value and ease of storage and preparation. Programs targeting such groups often use eggs and poultry meat as key components to improve nutritional outcomes, as recently reported in a study focused on programs from sub-Saharan Africa and South Asia regions [20]. Another important economic aspect is that poultry species are more resilient to climate variations compared to larger livestock, and they can be raised in diverse environmental conditions [21,22], from tropical to temperate climates, making poultry farming a reliable source of food even under changing climatic conditions. Lastly, poultry production generally emits fewer greenhouse gases per unit of meat compared to ruminant livestock [23], supporting sustainable food systems that balance food production with environmental conservation.

From a cultural point of view, poultry is widely accepted across different cultures and religions, making it a versatile and important component of global diets [24]. This cultural acceptance facilitates its inclusion in various food security initiatives without significant dietary restrictions. In this context, the importance of poultry products (eggs and meat) in global food security cannot be overlooked, as it supports the dietary needs of billions humans, particularly in regions where other forms of animal protein are scarce or too expensive for the average consumer [25]. Furthermore, poultry farming is often integrated into larger agricultural practices, providing a steady income stream for smallholder farmers, who represent a significant portion of the world’s agricultural producers. These small-scale operations contribute not only to local food security but also to the livelihoods of millions of families, thereby reinforcing the socio-economic stability of rural areas, as shown in a study conducted in South Asia [26].

2.3. Poultry Production and the Circular Economy

The concept of a circular economy is gaining massive attention in discussions about sustainable agriculture, which includes poultry production. A circular economy approach in poultry farming emphasizes the efficient use of resources, waste minimization, and the recycling of discarded by-products [27]. This approach aligns closely with the principles of SDG by reducing environmental impacts, such as carbon footprint, and enhancing resource efficiency, which in the context of SDG 2 are considered critical aspects. Generally, traditional poultry feeding practices rely heavily on common grains such as corn, wheat, and soybeans, which are also staple foods for humans [28]. This competition for these common resources can amplify food insecurity, especially in regions where grain production is not sufficient to meet both human and animal needs. Therefore, the transition to more sustainable feeding practices is essential. Alternative feed ingredients such as insect protein, algae, and agricultural by-products and wastes [29–31] represent promising solutions for reducing the environmental footprint of poultry production. Insects, for example, can be produced using organic waste, which not only diverts waste from landfills but also creates a high-protein feed source for poultry [29]. Algae, another alternative, can be cultivated in environments that are unsuitable for traditional agriculture, making it a viable option in arid regions [30]. Agricultural by-products, such as oil seed meals [31], hulls [32], and other residues (fruits and legumes) from crop production [33–35], can also be repurposed as poultry feed ingredients, thereby closing the loop in agricultural systems and promoting a circular economy. The adoption of these alternative feeding strategies can lead to significant reductions in the environmental impacts of poultry farming. For instance, insect-based feeds have been shown to lower greenhouse gas emissions [36] and reduce the reliance on water-intensive crops like soy. Additionally, it was recently reported in a case study [37] that by utilizing waste materials as feed, the poultry industry can contribute to reducing overall food waste, which is a significant challenge in the global food system.

2.4. Challenges in Implementing Sustainable Feeding Practices

While the benefits of sustainable feeding strategies are clear, several challenges hinder their widespread adoption, particularly when focusing on by-products, food waste, and plant-based alternatives. As recently mentioned in other studies focused on the valorization of food waste, one of the primary economic barriers is the variability in the availability and quality of by-products and food waste [38,39]. Unlike conventional feed ingredients, which are produced in large quantities with a consistent quality, by-products and food waste can vary significantly depending on their source, processing methods, and seasonal availability [40]. This inconsistency poses a challenge for formulating balanced poultry diets that meet nutritional requirements consistently. Another challenge is the presence of anti-nutritional factors and contaminants in plant-based alternatives and by-products. Many of these alternative feeds contain compounds such as tannins, phytic acid, and mycotoxins, which can interfere with the bioavailability of various components, nutrient absorption, and poultry health [41]. Another challenge is given by the influence of soil, climatic conditions, vegetation, and seasons, which will result in wastes with variability in their chemical composition. However, as recently reported, these issues can be addressed by additional processing steps, such as fermentation, enzyme treatment, or heat treatment [42], which later can increase costs and complexity for farmers, particularly those with limited resources.

The logistical challenges associated with collecting, processing, and distributing food waste and by-products also present significant barriers. Farmers often struggle to access alternative feed ingredients reliably and affordably due to the absence of established supply chains. Unlike traditional feeds that are mass-produced and distributed through established networks, by-products and food waste may need new infrastructure for collection, transportation, and storage. The same applies to food waste, which must be treated to make sure it is safe and nutritionally appropriate for poultry to eat. As reported by Salvador et al. [43], solutions to this concerning behavior are crucial for an adequate circular bioeconomy strategy. In addition, regulatory barriers can impede the adoption of sustainable feeding practices. Moreover, consumer perceptions and market acceptance play a crucial role in the success of these alternative feeding strategies [44]. There may be resistance to poultry products raised on diets that include by-products or food waste, especially in markets where traditional feeding practices are well established and preferred by consumers [44,45]. Educating consumers about the sustainability and environmental advantages of these practices as well as ensuring that the final poultry products meet high standards of quality and safety will be essential to building trust and acceptance.

3. The Purpose of Developing Alternative Poultry Feeding Practices

Current poultry feeding includes a variety of traditional and innovative methods designed to meet the nutritional needs of poultry, while improving productivity. Traditional poultry feeding practices are primarily based on well-established ingredients that have been shown to support poultry health and yield. Poultry feeding protocols are largely a matter of tradition, relying on standard ingredients known to help promote poultry health and production. Ingredients that are used frequently among traditional feed ingredients include grains, like corn and wheat, as primary energy sources, while soybean meal is mainly utilized in order to provide protein [46]. Some of these end products are mixed with animal by-products, fats, vitamins, and minerals. This results in a well-balanced diet tailored to the specific needs and growth of different poultry [42]. Balanced macronutrients (proteins, carbohydrates, and fats), as well as perfect combination of essential micronutrients (vitamins and minerals), are key factors to be considered in diet formulation for poultry. Formulating complete feed is important for the best performance and so as to avoid nutrient deficiencies, which can help to produce better chickens’, health-wise, regarding their production qualities. However, even the most effective traditional diets are not without their pitfalls. A major challenge is the high costs and price fluctuations of common feed ingredients, such as corn and soybean meal [47,48]. These costs can be limitative for resource-limited smallholder farmers, affecting their profitability and sustainability. Furthermore, the heavy reliance on particular crops raises concerns about the environmental impact of their agriculture on the environment, with issues such as deforestation, water consumption, including its use, and greenhouse gas emissions. To address these challenges, there is growing interest in exploring alternative feed ingredients that can supplement or replace entirely, if possible, the conventional ones [42,49]. These ingredients can provide valuable nutrients while potentially reducing feed costs and environmental impacts. However, their nutritional profiles as shown in Table 1 and effects on poultry health, performance, and product quality need to be thoroughly evaluated to ensure they meet the birds’ needs.

Table 1. Chemical composition and bioactive compounds determined in different plants, waste, and their co-/by-products.

Sustainable Poultry Feeding Strategies for Achieving Zero Hunger and Enhancing Food Quality - Image 1

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Another innovative approach in poultry feeding practices is the use of feed additives and supplements designed to enhance feed efficiency and animal health. Pliego et al. [123] reviewed the beneficial effects of medicinal and herbal plants, while other authors explored the uses of legumes [124,125], fruit pomaces and co-products [126,127], and other unexplored plants by/co-products [128,129] are nowadays used to improve digestion, nutrient absorption, and gut health. These additives can be particularly beneficial when incorporating alternative feed ingredients, as they help mitigate potential nutritional imbalances and enhance the bioavailability of nutrients, resulting in products with improved nutritional quality, which can further provide nutritious and healthier affordable food products. Sustainable feeding practices are also gaining attention as producers seek to reduce the environmental footprint of poultry production [130]. This involves optimizing feed formulations to minimize waste and enhance nutrient utilization, as well as adopting practices that promote resource efficiency. It was shown recently by Lefter et al. [131] that locally sourced ingredients that match the dietary supply of the birds’ nutritional requirements can be a sustainable approach. Such a strategy will also contribute to reducing transportation emissions and environmental pollution.

These evolving practices are directly aligned with the SDG2 of Zero Hunger by adopting innovative feeding strategies, ensuring the availability of nutritious and affordable poultry products. These strategies not only enhance the animal’s production performances and the quality of food but also support the sustainability of food systems, making a substantial impact on global food security.

4. Innovative Feeding Strategies for Sustainable Poultry Production

Sustainable feeding strategies in poultry production focus more on the use of alternative feedstocks to overcome the challenges of traditional feed practices, such as high cost, input restrictions, and environmental impact. These alternatives can replace conventional ingredients such as corn and soybean meals [132] and include plant substitutes such as wastes from legumes, oilseeds, plants, and various agricultural co-/by-products. Furthermore, some recent review reports showed that other unconventional sources like insects [133], algae [134], and food waste [135] are being investigated for their potential as sustainable alternative poultry feed ingredients. The benefits of using plant-based and by-product feeds are manifold. First, these innovations can significantly reduce feed costs, making chicken production economically viable, especially for smallholder farmers with limited resources. Secondly, many of these substitutes are by-products of other agricultural practices, which means they can be obtained cheaply and even contribute to reducing waste in the feed system. Moreover, additional feed supplementation to poultry feed can reduce competition between feed and food crops, resulting in more balanced agricultural sustainability [136].

Nutritionally, many alternative feed ingredients offer a diverse array of essential nutrients that can meet the dietary needs of poultry. For example, legumes and oilseeds are rich in proteins and amino acids, while by-products provide valuable energy, fibers, and numerous beneficial bioactive compounds [42]. Babatunde et al. [136] recently stated that the use of alternative feeds can enhance the resilience of poultry production systems. By diversifying their feed base, producers can reduce their vulnerability to market fluctuations and supply chain disruptions that commonly affect the availability and price of conventional feed ingredients. Other authors [137,138] showed that this resilience is particularly important in the context of global food security, as it helps ensure a steady supply of poultry products even in times of economic or environmental stress. All in all, such feeding strategies that incorporate alternative feed ingredients hold significant promise for advancing the goals of Zero Hunger and sustainable agriculture.

Furthermore, by reducing costs, minimizing environmental impacts, and improving the nutritional profile of poultry diets and final products, these feeding strategies can enhance the sustainability and productivity of poultry farming, aligning also to the principles of the 3 R’s, which can now be considered as 5 R’s (Figure 2).

Figure 2. The principle of the 5 R’s for alternative sustainable poultry production system.

4.1. Plant-Based as Alternative Feed Ingredients

Plant-based feeds have long been a cornerstone of poultry feed, primarily due to their availability, low cost, and high nutritional value. Traditional plant-based feeds, such as corn, barley, wheat, and soybean meals, are used as main sources of energy and protein, making them ideal for supporting fast growth and productivity in poultry [135]. But as demand for these crops increases worldwide for human consumption and animal feed, competition for agricultural products has intensified, as noted by Frona et al. [139]. This has raised concerns about sustainability as they rely heavily on these foods. In response to these challenges, researchers and industry stakeholders are looking for plant-based alternatives that are not only nutritious but also sustainable. These alternatives take less resources to manufacture, which are usually obtained as commodities resulting from other agricultural methods. For example, lupins, faba beans, chickpeas, and peas [140] are gaining attention as potential protein sources due to their high protein content and low environmental impact compared to soybeans. Similarly, oilseed meals like canola, flax, and rapeseed meal [87], which are by-products of oil extraction processes, offer substantial protein and fat content and can partially replace soybean meals in poultry diets.

Another promising approach is the use of agricultural residues and by-products as feed ingredients. These include rice bran, wheat bran, and other cereal by-products that are commonly discarded or used in low-value products [141]. These products can be recycled as poultry feed, contributing to a circular economy, which will result in reducing waste and improving food production. The challenge of using such by-products is in their variable nutrient content and potential presence of anti-nutritional compounds [142], which requires careful formulations and processing when it comes to poultry nutritional needs to ensure that they do not compromise health or performance.

In addition to diversifying the sources of plant-based feed ingredients, there is ongoing research into enhancing the nutritional quality of these alternatives. Some techniques, such as fermentation, enzyme supplementation, and genetic modification, are being explored to improve the digestibility and nutrient availability of plant-based feeds, as revived by Samtiya et al. [143]. The shift towards more sustainable plant-based feed alternatives also aligns with broader environmental goals, as they have a lower carbon footprint compared to animal-based feeds [144], and their production often requires less water and land. This makes them an attractive option for reducing the environmental impact of poultry farming, particularly in regions facing resource constraints. Nevertheless, the transition to these alternative plant-based feeds is not without challenges. Economic factors and challenges, like the cost and availability, the variability in nutrient content, and the presence of anti-nutritional factors of these ingredients, can be significant barriers to their worldwide implementation. Despite these challenges, the continuous research and development efforts in this area are paving the way towards more sustainable and resilient poultry production systems.

4.2. Insect-Based as Alternative Feed Ingredients

Over the past 10 years, insect-based feed has emerged as one of the most promising poultry alternative protein sources due to its high nutritional value, low environmental footprint, and potential to contribute to a circular economy. As the demand for sustainable livestock feed increases, insects such as black soldier fly larvae, mealworms, and crickets are increasingly recognized for their ability to efficiently convert organic wastes into highquality protein sources [145,146]. Insects are highly nutritious, with protein content ranging from 30% to 80% depending on species and growth stage. These are rich in essential amino acids, fats, and minerals, making them a viable alternative to traditional protein sources such as fish meal and soybean meal [145]. For example, black soldier larvae have a balanced amino acids profile as reported by Khalifa et al. [133], while insect feed can provide essential fatty acids such as n-3 and n-6, which are essential for poultry health and productivity. Insects also have the advantage of being able to efficiently convert organic waste into biomass. They can be raised on a variety of natural materials, such as agricultural residues, food waste, and even garbage, making them an integral part of the waste management process. Not only does this diminish the environmental impact of waste disposal but also provides a valuable by-product of the process in the form of insect proteins [147]. By recycling waste into feed ingredients, insect farming supports the principles of a circular economy, reduces reliance on traditional feed crops, and reduces the overall carbon footprint of poultry production, as mentioned by Chavez et al. [148]. Despite the clear benefits, there are challenges associated with the use of insect-based feeds in poultry diets. One of the main barriers is the regulatory framework governing the use of insects in animal feed. In many regions, the approval process for insect-based feed ingredients is still in its early stages, and there are strict regulations regarding the substrates that can be used for insect rearing [149]. However, in a recent study conducted by Zuk-Gołaszewska et al. [ ˙ 150], it was reported that H. illucens, M. domestica, T. molitor, A. diaperinus, G. sigillatus, A. domesticus, and G. assimilis insect species fulfil safety conditions as insect production for feeding purposes, according to European Commission Regulation no. 893/2017, European Parliament Regulation no. 999/2001, and of the European Council and Commission Regulation no. 142/2011. This approval is important and ensures the safety and quality of insect meals in terms of contaminants that can potentially be transferred to the poultry. Another challenge is the scalability and economic viability of insect farming. While insect farming is less resource-intensive compared to conventional agriculture, Madau et al. [151] reported that it requires significant investment in infrastructure and technology to be scaled up to a level where it can meet the demands of the poultry industry. Other authors [152] mentioned that the cost of insect protein is currently higher than that of traditional feed ingredients, although this is expected to decrease as the industry matures and production processes become more efficient. All in all, ongoing research is exploring ways to optimize insect farming practices, improve the nutritional quality of insect meals, and assess the long-term effects of insect-based feeds on poultry health and productivity. Studies have shown that insect protein can successfully replace a significant portion of conventional protein sources in poultry diets without negatively affecting growth performance or feed efficiency [133,145]. In some cases, the inclusion of insect protein has been associated with improved gut health and immune function in poultry [153,154], suggesting potential additional benefits beyond basic nutrition.

4.3. Co-/By-Products and Wastes as Alternative Feed Ingredients—Nutritional Composition and Bioactive Compounds

The nutritional content of alternative poultry feed ingredients is an important factor in determining their suitability for poultry feed. Poultry species require a balanced diet of proteins (16 to 18% for laying hens; 20 to 23% for broilers), essential amino acids such as lysine (0.9 to 1.1% for laying hens; 1.1 to 1.3% for broilers), methionine (0.4 to 0.5% for laying hens; 0.5 to 0.6% for broilers), threonine (0.6 to 0.8% for laying hens, 0.8 to 1.0% for broilers), and tryptophan (0.2% for both hens and broilers), carbohydrates (50 to 60% of the total diets), fats (3 to 6% of the total diet), vitamins such as A (7500 to 12,000 IU/kg), D3 (2000 to 3000 IU/kg), and E (10 to 20 mg/kg)and minerals like Ca (3.5 to 4.5% for laying hens; 1% for broilers) and P (0.45 to 0.5% for both hens and broilers) to maintain optimal health, growth and productivity. These nutritional requirements are mentioned in each hybrid management breeding guide. The chemical composition of alternative feeds varies greatly depending on the source, but in general, these products provide essential nutrients that support poultry health and yield. A comprehensive understanding of the nutritional value of these new ingredients is essential for composing a balanced diet. These components include protein, fiber, fat, a mixture of vitamins and minerals, and several bioactive compounds, as shown in Table 1. After an extensive literature review, we classified several sources, compounds, and plant and vegetable food wastes based on their genus and identified them as potential sources of new alternative feed ingredients for poultry nutrition.

The literature revealed that the Apiaceae family includes plants, such as carrots, parsnips, celery, fennel, coriander, parsley, dill, anise, and lovage, which are known for their rich medicinal properties and potential bioactive compounds. Carrot (Daucus carota) waste exhibits a wide range of nutrients in different areas, including high levels of carotenoids such as β-carotene and α-carotene, especially in orange, black, and purple varieties, which also exhibit strong antioxidant activity [33,51]. Carrot flour and leaves contain significant amounts of TPC and TFC, contributing to their nutritional value [52,53]. Parsnip roots (Pastinaca sativa) are notable for their high dry matter content, monosaccharides, disaccharides, and minerals. They also contain substantial TPC and antioxidant capacities, enhancing their health benefits [54]. Celery (Apium graveolens) in its bulbs, leaves, and roots offers high levels of protein, fiber, and the essential minerals, with significant amounts of choline, pantothenic acid, and rutin in the leaves contributing to its resistance against infection [55–58]. Fennel (Foeniculum vulgare) seeds and shoots contain proteins, fats, carbohydrates, and essential fatty acids like PUFA and other essential fatty acids; the seeds also contain vitamins B1, B2, and niacin [59,60]. Anise (Pimpinella anisum) seeds contain protein and fiber content and are rich in TPC, carotenoids, tannins, and various phenolic compounds, making them more nutritious, as reported by Sun et al. [61] and Ghosh et al. [62]. In addition, the leaves and seeds of coriander (Coriandrum sativum) contain high levels of protein, fiber, essential minerals, and vitamins, with the leaves containing high levels of vitamin C and the seeds containing high levels of MUFA and PUFA [63,64]. Parsley (Petroselinum crispum) leaves are particularly rich in protein, fiber, vitamins, and phenolic compounds, which confer significant antioxidant properties, according to Cornescu et al. [65] and Dobricevich et al. [66]. In addition, the leaves and stems of dill (Anethum graveolens) contain large amounts of vitamin C, carotenoids, β-carotene, and TPC [67], while the leaves and stems of lovage (Levisticum officinale) provide essential proteins, carbohydrates, and fatty acids, with significant amounts of n-3 and n-6 fatty acids [68,69].

Another important alternative feed ingredient is represented by the fruits of American and European elderberries. These unexplored sources are rich in total phenolics, exhibit significant antioxidant capacity, and contain various essential nutrients such as glucose, fructose, proteins, and a variety of minerals, including K, P, Ca, and Mn [70]. They also contain notable amounts of anthocyanins, which contribute to their health benefits. However, they also have trace amounts of toxic compounds like sambunigrin [70,71]. The flowers of European elderberry are also rich in phenolics and proteins and exhibit strong antioxidant activity and minerals like Ca, Mn, Fe, Cu, and Zn [71,72].

Jerusalem artichoke (Helianthus tuberosus) are tubers from the Asteraceae family that are rich in carbohydrates and inulin, making them a significant source of dietary fiber. They are also a good source of Ca and K with high TPC content [73]. The Jerusalem artichoke leaves vary widely in protein content and are high in fiber. They are also rich in minerals (Ca, Mg, and K) and contain notable amounts of carotenoids [74,75]. Chicory (Cichorium intybus) roots have high inulin content (44.69%) and provide significant amounts of carbohydrates (89.41%). The roots are also rich in phenolic acids, such as chlorogenic and caffeic acids, which contribute to their antioxidant properties [76]. The leaves of chicory contain a notable amount of TPC and a variety of phenolic compounds, including protocatechuic and caffeic acids [76]. The chicory seeds are rich in protein (18.61%) and fat (21.18%) and contain high levels of Fe, Cu, and Zn, along with a modest amount of vitamin C [77]. Some authors [78,79] revealed that calendula (Calendula officinalis) flowers are high in TPC and TFC, with notable levels of tocopherols, containing significant amounts of carbohydrates and organic acids. Similarly, dandelion (Taraxacum mongolicum) has high antioxidant activity in its flower, leaves, and stem, with TPC values ranging from 23.89 to 30.05 mg GAE/g dry weight. The flowers and leaves are also rich in vitamin C and carotenoids, with notable levels of Ca and Mg [80]. Another important agricultural crop that produces waste is lettuce (Lactuca sativa). Although the results presented by Mampholo et al. [81] show variation in antioxidant content across different varieties, they present important bioactive compounds suitable as alternative feed ingredients in poultry [81,82]. Moreover, artichoke (Cynara cardunculus), particularly the receptacle and heads, were reported as rich sources of inulin and various minerals. The receptacle has high dry matter and protein content, while the heads contain a balance of fats, carbohydrates, and antioxidants [83,84]. Lastly, another important crop with high protein and fat content and a notable amount of PUFA in both wild and commercial varieties is the yarrow (Achillea millefolium). The commercial inflorescences have higher fat and protein levels, contributing to their nutritional profile [85].

In the Arecaceae family, coconut (Cocos nucifera) shell waste was identified as a source of high crude fiber (32.39%) and carbohydrate content (52.63%). Ewansiha et al. [86] showed that despite its low protein and fat levels, the shell is rich in Fe (618 mg/100 g), making it a significant source of this mineral.

The Brassicaceae family includes several nutritionally significant plants. Rapeseed (Brassica napus) is notable for its various components, such as meals, seeds, and cake. The meal is a rich source of protein and healthy fats, including significant amounts of MUFA and PUFA, and it contains valuable antioxidants and phenolic compounds [5]. Rapeseed seeds offer a substantial amount of crude protein and fat, with a noteworthy balance of n-3 and n-6 fatty acids. These seeds also provide essential minerals and fiber, making them a nutritious food source [87]. The cakes, which are by-products of oil extraction, are rich in protein and healthy fats, as well as essential fiber and minerals [87]. The kale (Brassica oleracea) leaves are another member of the Brassicaceae family, known well for having numerous essential nutrients (dietary fiber, vitamins, and minerals, including vitamin C and beta-carotene), and exhibit strong antioxidant properties due to their high phenolic content [88]. Similarly, mustard seeds (Brassica juncea) were reported by Oancea et al. [89] to contain high protein and fat content and are particularly rich in essential minerals such as Fe, Mg, and Zn. These seeds contain a variety of beneficial antioxidants and vitamins, contributing to their health-promoting properties. Commonly discarded cabbage (Brassica oleracea) waste is high in protein, fiber, and various minerals [90], making it a valuable source of nutrients.

Another important by-product belongs to the Cannabaceae family, which includes hemp (Cannabis sativa), whose seeds are highly nutritious, containing a balanced profile of proteins and fats, including a high proportion of PUFA. Mierlita et al. [91] reported recently that they offer significant amounts of dietary fiber and antioxidants, such as tocopherols and carotenoids, suitable for poultry nutrition.

In the Cucurbitaceae family, cucumbers (Cucurbita pepo) yield edible parts, such as flesh, peel and seeds, which are suitable for poultry feed, each with their own unique nutritional value. The flesh is low in calories but rich in vitamins and minerals. However, the peel contains high levels of protein, fiber, and antioxidants [92]. Cucumber (Cucumis sativus) and watermelon (Citrullus lanatus) also belong to this genus, where cucumber stands out for its high-water content and various mineral and vitamin properties in organic matter, extract, and juice, which are important [93,94]. Pumpkin seed meal (Cucurbita moschata) is also a rich source of protein, fat, and beneficial n-3 fatty acids [95].

Sea buckthorn (Hippophae rhamnoides) from the Elaeagnaceae family, whose leaves and fruits are rich in protein, fat, and antioxidants, contains important minerals and vitamins, making them highly nutritious and suitable for poultry nutrition [31,96]. Additionally, other important co-products are the leaves and flowers of Elaeagnus angustifolia, which were reported by Saboonchian et al. [97] as sources rich in phenolic and flavonoid compounds. The fruits of this plant provide a good source of fats, including a balanced ratio of SFA and UFA, along with significant amounts of antioxidants [98].

In a recent study, conducted by Untea et al. [99], it was revealed that the Ericaceae family cranberry (Vaccinium macrocarpon) offers significant nutritional benefits, particularly in its leaves. These coproducts contribute to a robust nutrient profile that includes protein, fat, fibers, and essential minerals such as Fe, Mn, and Zn.

The alfalfa plant, scientifically known as Medicago sativa and belonging to the Fabaceae family, is well known for its remarkable nutritional value. The alfalfa plant is abundant in protein and fiber, and it also has significant levels of healthy fats, such as a high proportion of PUFA. Alfalfa is additionally a beneficial supplier of antioxidants, such as tocopherols and carotenoids [100]. Pea (Pisum sativum) seeds are a beneficial legume, offering a good amount of protein and important nutrients such as tocopherols. Peas provide a beneficial combination of carbs, fiber, and fats [101]. Lentil seeds, containing high levels of protein and fiber, as well as a notable quantity of PUFA, are a healthy option for nutrition. Lentils have sugars and tocopherols that enhance their nutritional worth [102].

Mung bean (Vigna radiata) seeds are rich in protein and fat, and they offer antioxidant benefits through their TPC and TFC [103].

One important by-product from the Juglandaceae family includes walnuts (Juglans regia), whose meal is highly nutritious, contains protein and essential lipids, with a significant amount of antioxidants, including phenolic acids and flavonoids, as well as essential minerals, such as Mg and Zn, and has a high TAC [99].

The Lamiaceae family encompasses several aromatic herbs with notable nutritional profiles. Spearmint (Mentha spicata) leaves are characterized by their high dry matter content and significant levels of fiber and phenolic compounds [104]. Basil (Ocimum basilicum) leaves are rich sources of nutrients such as protein, fiber, and essential minerals and contain a balanced profile of fatty acids along with substantial antioxidant activity [24]. Thyme (Thymus vulgaris) leaves also have a high TPC and TAC, with a substantial amount of essential minerals and beneficial fatty acids [24]. Sage (Salvia officinalis) leaves are another member of this family with a high protein and fiber content and contain significant levels of antioxidants, including vitamin E and lutein [24]. Rosemary (Rosmarinus officinalis) leaves are noted for their high antioxidant content, including phenolic compounds and vitamin E, although they contain relatively lower levels of protein and fat compared to other herbs [105].

The Liliaceae family includes garlic (Allium sativum), which is valued for both its bulb and leaves. The bulb is noted for its high content of dry matter and minerals, alongside significant amounts of monosaccharides and disaccharides. The antioxidant properties of garlic are also noteworthy, with appreciable TPC and TAC [54]. In contrast, garlic leaves exhibit high protein content and crude fiber, along with notable antioxidant levels including TPC and TAC [106]. Onion (Allium cepa) waste provides a broad range of nutrients, with variability in dry matter, protein, and mineral content such as K, Ca, and Mg. The antioxidant properties are also significant, with variations in TPC and TFC as reported by Benítez et al. [107]. Further, another important crop, asparagus (Asparagus officinalis), offers a diverse nutritional profile, including fibers, sugars, proteins, and a variety of vitamins such as B and C vitamins and essential minerals like Ca and Mg [108].

In the Musaceae family, important food wastes are produced by plantain and banana peels. Plantain peel is rich in carbohydrates and contains essential minerals, including K and Mg, with moderate levels of protein and fat [109]. Similarly, banana peel is characterized by its high carbohydrate content and significant levels of fiber and minerals, though with slightly lower protein and fat content compared to plantains [109].

The Oleaceae family includes olive (Olea europaea) seeds, which are rich in lipids, especially MUFA and PUFA. The seeds also provide various sterols and essential minerals, contributing to their nutritional richness as alternative feed ingredients [110].

Within the Rosaceae family, the nutritional profiles of apple (Malus domestica) and rosehip (Rosa canina) are distinct. Apple waste (peels, seeds, and pulp) is rich in TPC and TFC, with varying levels of K, Ca, and Mg [111]. Rosehip meal and seeds offer a high dry matter content and are rich in antioxidants, including high levels of PUFA, with substantial amounts of vitamin C and carotenoids [6,112]. The co-products of raspberry and blackberry (Rubus spp.) leaves have been recently shown to have a high dry matter content and are rich in proteins, fibers, and essential minerals. They also have significant levels of antioxidants and carotenoids [113]. Strawberry leaves are noted for their protein content and high TAC [114]. Another important crop that recently gained attention are the aronia (Aronia melanocarpa) fruits, leaves, and pomace, which were described by Saracila et al. [115] to be rich in dry matter and provide a balanced profile of nutrients including carbohydrates, proteins, and fats, along with high levels of Fe, Mn, and Zn.

Further, in the Rutaceae family, citrus fruits are prominent for their diverse nutritional benefits. Citrus aurantium, or orange, peels are known for having high levels of total polyphenol content (TPC) and large total antioxidant content (TAC), as expressed in terms of both vitamin C and E equivalents. The peel is also high in lutein and zeaxanthin, which are critical for eye health, and has a little amount of crude protein, fat, and fiber [116]. Similarly, the peel of grapefruits (Citrus paradisi) displays a strong TPC and TAC pattern, but it also has somewhat greater crude protein and fiber content than orange peel. Important antioxidants found in grapefruit peel include vitamin E and carotenoids like lutein and zeaxanthin [116]. Conversely, lemons (Citrus × limon) offer a more significant nutritional profile, including high levels of fiber, protein, and important minerals like Mn, Ca, and K. The high nutritional density of lemon peel, particularly with regard to minerals, underscores its potential to augment dietary consumption of these components [117].

As further highlighted by Panaite et al. [50], tomato (Solanum lycopersicum) waste is a member of the Solanaceae family and is rich in crude protein and fiber. It is also notable for its high amount of PUFA and carotenoids, such as lycopene and beta-carotene, which are known for their antioxidant effects. Waste from bell peppers (Capsicum annuum) is a good source of carotenoids and vitamins C and E. The varying TPC and TFC across different bell pepper samples underline its antioxidant potential [118]. Eggplant (Solanum melongena), both in its fruit and pulp forms, has relatively low levels of protein and fat but provides a balanced ratio of lipids [119].

Within the Vitaceae family, grape (Vitis vinifera) pomace and seed meal are the most important and studied sources rich in both PUFA and antioxidants. The pomace is high in crude protein and fiber, with a significant amount of fatty acids and a balanced profile of SFA, MUFA, and PUFA [120]. The seed meal, which contains high dry matter content, shows substantial antioxidant activity and a similar fatty acid profile, though with a higher proportion of unsaturated fats [121].

Lastly, in the Zingiberaceae family, ginger (Zingiber officinale) rhizome, known for its aromatic and medicinal properties, is primarily composed of carbohydrates and moisture, while its nutritional content is complemented by trace amounts of protein, fat, and fiber, and it contains gingerol, a compound with known health benefits [122].

All these reviewed plants, by-products, co-products, and plants, containing various amounts of nutrients and bioactive compounds, have been reported as safe and with multiple benefits when used in poultry diets, as presented further in Table 2.

5. Effects of Reviewed Alternative Feed Ingredients on Poultry Performance, Health Status, and Product Quality

In recent studies, various plants from different botanical families have been explored for their effects on poultry performance, health, and product quality. Each plant species tested by researchers showed unique impacts and effects depending on the poultry hybrid, dosage, and part or type of the plant used, as summarized in Table 2.

The reviewed alternative feed ingredients from the Apiaceae family demonstrate significant potential in improving the health and productivity of poultry through enhanced nutrient intake, better egg and meat quality, and improved immune responses. Carrot waste has shown positive effects on both laying hens and broilers. In laying hens, carrot waste was effective in improving internal and external egg quality [50]. Similarly, carrot leaf increased production performances and nutrient digestibility, as reported by Siti et al. [122], as well as egg quality. Anise seed, according to the results of Barakat et al. [155], was effective in improving the immune system of broilers and meat quality. For broiler chickens, coriander seed at a 1.5% dose was most effective in improving dressing percentage and the overall health status of the broilers [156]. Parsley leaves tested in laying hens raised under heat stress conditions improved production performances and antioxidant compounds in eggs [65], as well as the quality characteristics of eggs during 28 days of storage. In broiler chickens, parsley leaves in higher doses significantly increased feed intake and carcass quality and health parameters, according to Ali et al. [157]. The dill leaves in lower doses used in broiler chickens significantly improved production performance and improved lipid metabolism [158,159].

The reviewed alternative feed ingredients from the Asteraceae family exhibit various beneficial effects on poultry health and performance. The incorporation of these plants and their by-products into poultry diets can lead to improved growth rates, better immune responses, enhanced egg quality, and improved health status of poultry, aligning with sustainable feeding strategies and contributing to improved food quality and security. Jerusalem artichoke was evaluated for its effect on broiler chickens’ diets, which significantly improved production performance, as reported by Al-Abboodi et al. [160]. Chicory has demonstrated several beneficial effects in broiler chickens, showing a significant reduction in abdominal fat pad and improved health status [161]. In laying hens, free access to chicory vegetation resulted in better production performance and improved lipid composition in the eggs [162]. Calendula flower supplement in broilers improved carcass yield; however, more than 1% could affect production performances [163]. In layers, petal and leaf supplements significantly increased carotenoid deposition in egg yolks, with no effect on egg production or quality characteristics [164]. Dandelion leaves and meal in different broiler hybrids and laying hens was demonstrated to be effective in improving product quality (meat and eggs) as well as production performance and health status [165–167]. However, in laying hens, a 4% dandelion meal had detrimental effects on feed consumption and egg weight, as shown by Saenz et al. [168]. Similar effects were reported for echinacea supplementation in broiler chickens, demonstrating its potential in improving health and performance [169].

Ginseng was not very effective when tested in laying except for a notable increase in egg production, according to Kang et al. [170], however, had a notable effect on the health status of laying hens.

Rapeseed has been extensively studied as an alternative feed ingredient for poultry. In broilers, rapeseed can be used up to 30% without detrimental effects on production performances, while in laying hens’ lower levels < 20% are preferred [171]. The same effect was noted by others in laying hens [172]. In terms of egg quality, rapeseed meal had a significant impact on n-6 PUFA and health-related indices [5].

According to Mustafa et al. [8], broccoli waste up to 9% was suitable for broiler chickens’ diets, with significant effects on production performance and nutrient digestibility. In a different study with broiler chickens, broccoli stem and leaf meal had no effect on growth performance but significantly increased antioxidant compounds in meat samples and enzyme activity [173]. For laying hens, broccoli stem and leaf meal did not affect production performance but significantly increased the xanthophyll content in egg yolk and decreased cholesterol content [174]. Further, cabbage waste in broiler chickens had no effect on production performance but improved nutrient digestibility [175]. In laying hens, cabbage waste up to 12% significantly improved egg quality, however, might negatively impact eggshell percentage [176]. These findings suggest that incorporating by-products from the Araliaceae and Brassicaceae families into poultry diets can enhance production performance, immune responses, and nutrient digestibility and health, contributing to sustainable feeding strategies and improved food quality.

Hemp seed by-products also have shown promising results when included in poultry diets. In broiler chickens, hemp seed cake significantly improved the fatty acid profile in the thigh and breast meat and health status but had no significant effects on performance, as shown by Tufarelli et al. [177]. In laying hens, significant effects were reported on both egg quality and performance [91].

Pumpkin (Cucurbita pepo) seed meal up to 20% inclusion levels in broiler chickens significantly increased production performance, with no effect on commercial parts [178]. The watermelon (Citrullus lanatus) rind in laying might have some detrimental effects on egg weight, but the overall health status was significantly improved [126]. However, further research is required. Pumpkin (Cucurbita moschata) seed meal significantly improved shelf-life and egg quality parameters in laying hens [95].

In broiler chickens, dietary supplements with cranberry leaves stimulated the deposition of bioactive compounds in meat samples and exhibited a strong effect in counteracting oxidative processes in broiler meat [99,128]. A 30% cranberry pomace in broilers diet significantly affected nutrient absorption but improved the plasma lipid profile [179]. These findings support the potential of these plant by-products from the Cannabaceae, Cucurbitaceae, and Ericaceae families as sustainable alternative feed ingredients in poultry nutrition, contributing to improved food quality and Zero Hunger initiatives.

Alfalfa (Medicago sativa) from the Fabaceae family has been extensively studied for its beneficial effects in poultry diets as a dietary fiber source. In broiler chickens, up to 5% was demonstrated to be effective in improving antioxidant compounds in meat except carotenoids content while maintaining the production performances [100,180]. In laying hens, 5 to 10% dietary alfalfa meal significantly decreased FCR, mortality, abdominal fat yield, and egg yolk cholesterol content while demonstrating potential health benefits [181,182]. Pea (Pisum sativum) has also been explored for its potential as an alternative protein and energy source. In broiler chickens, 4 to 48% raw pea was used as a replacement for soybean meal and corn, which had no detrimental or additional effects on meat quality, as mentioned by Dotas et al. [183]. Another group of authors reported significant effects on meat quality and significant improvements in health-related indices [184].

In a study by Untea et al. [128], walnut meal, when included in the diets of broiler chickens, improved meat lipid and nutritional composition; however, some minerals’ ability to deposit in the tissue was affected [99]. These plant-based feed ingredients from the Fabaceae, Cucurbitaceae, and Juglandaceae families offer promising alternatives to traditional feed ingredients, improving meat and egg quality, enhancing health parameters, and contributing to sustainable poultry production practices.

Further, several plants from the Lamiaceae family, including peppermint, spearmint, basil, thyme, rosemary, and sage, have been investigated for their effects on broiler chicken diets. Each of these plants showed varying impacts on production performance, meat quality, and health parameters. Peppermint significantly improves oxidative stability and immune responses [185], while others showed its potential effects on production performance [186]. Spearmint also influenced the performance of broiler chickens while reducing cholesterol levels and increasing hemoglobin and superoxide dismutase activity, as showed by Abu Isha et al. [187]. Basil and thyme, when included in the diet of broilers, had similar effects. Both herbs decreased production performance; however, they significantly improved the deposition of bioactive compounds in breast and thigh meat samples [24,180]. Moreover, rosemary in broilers improves intestinal health, with potential negative effects above 1.5% inclusion on production performance [188,189]. Sage leaves had similar effects as basil and thyme [24,180]. Overall, these findings highlight the potential of Lamiaceae plants to modulate various aspects of broiler chicken health and production. While some herbs like peppermint and spearmint can improve production performance at optimal inclusion levels, others like basil, thyme, and sage offer more substantial benefits in enhancing meat quality, particularly in terms of antioxidant and lipid profiles. However, the inclusion rates are critical, as higher levels can sometimes lead to decreased performance metrics.

Avocado seed meal reduced BW without affecting FCR, as showed in the study by George et al. [190], while another group of authors [191] reported that using up to 8% seed meal found no significant effect on broilers health, indicating that avocado seed meal does not negatively affect broilers’ health.

Garlic (Allium sativum) was found to have varying effects based on its preparation and dosage. In laying hens, garlic had no effect on productivity and egg characteristics but significantly improved the bird’s health status [192]. Raw garlic powder slightly improved broiler performances but influenced meat aroma; however, boiled garlic powder did not show these beneficial effects, indicating that the method of preparation plays a critical role in the efficacy of garlic as a supplement [193]. Onion (Allium cepa) demonstrated similar effects to garlic in laying hens.

Plantain peel waste is a suitable maize substitute in broiler finisher diets, with a recommended inclusion rate of up to 10% for optimal blood characteristics [194].

Olive leaf powder in laying hens had no significant effect on production performances but improved egg yolk quality, making olive leaf powder a potential agent for reducing egg yolk cholesterol [195]. In broilers, olive pulp waste improved footpad dermatitis and feather cleanliness without affecting growth performance or health [196].

Rosehip (Rosa canina) showed promising effects in laying hens by improving TAC and TPC in PUFA-enriched eggs while extending the shelf life of stored eggs [6]. In broiler chickens, low levels of rosehip fruits improved BW, FI, protein intake, and dressing percentages, as reported by Monesa et al. [197]. Another recent study showed that the leaves of rosehip, which are co-products, can be used as feed additives in the first stage of laying hens and could potentially improve the production performance and some egg quality parameters [70].

Citrus waste, such as orange (Citrus sinensis) and grapefruit (Citrus paradisi) peels, was tested in broiler chickens, and showed promising effects on performances, meat quality, and health status [116]; however, grapefruit peel decreased final BW.

Tomato wastes up to 7.5% enriched egg yolk quality; however, more than 7.5% level depressed the absorption and deposition of n-3 fatty acids in the yolk, indicating that optimal dosing is critical [34]. The 5% inclusion rate showed the best effect in this study.

The grape seed meal from the Vitaceae family was beneficial for broilers, significantly improving performance, meat quality, and health [121]. In laying hens, improved production performance and antioxidant compounds in eggs, although n-6 fatty acids were more prevalent than n-3 [5]. Recently, Costa et al. [198] concluded that in poultry, the effect of grape by-products is more variable, and these sources should not be incorporated in broiler diets at more than 6–10% to prevent an impairment of animal growth.

Ginger (Zingiber officinale) powder, when tested in broilers, had no effect on production performance; however, it reduced gizzard weight, indicating potential benefits for gut health [199].

These findings highlight the diverse impacts of alternative feed ingredients on poultry, emphasizing the importance of selecting the appropriate dosage and plant part to achieve desired outcomes in production performance, health status, and product quality, as detailed in Table 2.

Table 2. Main effects of plants when administered in poultry diets.

Sustainable Poultry Feeding Strategies for Achieving Zero Hunger and Enhancing Food Quality - Image 3

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6. Environmental and Economic Impacts and Limitations of the Presented Sustainable Poultry Feeding

6.1. Environmental and Economic Impacts of Sustainable Feeding Strategies

The shift towards alternative and sustainable feeding strategies in poultry production is driven not only by the need to improve nutrition and animal welfare but also by the imperative to reduce the environmental and economic impacts associated with conventional poultry farming. As the global demand for poultry products continues to rise, it is essential to adopt practices that minimize the carbon footprint, resource use, and economic costs of production [202]. The studies conducted by Campos et al. [203] and Osorio et al. [204] revealed that the use of agricultural by-products as feed ingredients contributes to a circular economy by recycling waste materials and reducing the environmental burden of waste disposal. This approach helps to lower the overall carbon footprint of poultry production. However sustainable feeding practices have obvious environmental benefits, chicken producers will only embrace them if they can be made economically viable [205]. However, the price of these substitute feeds should drop as the market for sustainable feed ingredients expands and manufacturing techniques advance. Economies of scale, advances in processing technologies, and increased competition in the market will likely drive down prices, making these feeds more accessible to a broader range of producers. Another economic consideration is the potential for alternative feeds to create new markets and revenue streams [206,207].

It is important to achieve a balance between environmental sustainability and economic viability for adopting alternative feeding strategies on a large scale. Moreover, there are surveys [208–210] suggesting that the rising awareness of environmental issues and preference for ethical food leads to increased customer demand for ecologically sustainable poultry products. As a result, such changes in consumer preferences can give rise to market opportunities for farmers who decide to go green in terms of their feed provisions, with possible high prices being charged on their goods.

However, moving away from conventional feeds poses challenges but also presents significant opportunities aimed at reducing the ecological burden from poultry farming as well as strengthening its economic resilience. Consequently, continued investments in research, technology, and policy support will be necessary towards unlocking the full potential of such approaches and making poultry production environmentally friendly in the long run.

6.2. Limitations of the Presented Alternative Sustainable Poultry Feeding

Feed control is a very important aspect in poultry diets, especially when incorporating fruit waste or other raw materials, due to their variability in nutritional composition. These materials offer potential nutritional benefits but also carry risks and limitations due to varying levels of anti-nutritive substances. In this regard, multiple levels of control are essential to ensure that the feed is both safe and nutritionally adequate for poultry. Poultry diets, as mentioned before, are composed of a balance of energy sources, proteins, vitamins, minerals, and additives, which all contribute to overall bird health and productivity. For these nutritional reasons, when including unconventional waste materials in poultry diets, several aspects must be carefully evaluated, as explained below.

The nutritional value of any ingredient, especially novel ones like fruit waste, needs to be thoroughly analyzed for proximate composition for basic nutrients (proteins, fats, and fibers), amino acids, fatty acids, and vitamins (like A, C, and E) content, knowing that they can vary in composition based on growing conditions and processing methods [211].

Anti-nutritional compounds present a significant challenge in alternative feed ingredients, especially tannins, saponins, phytic acid, and oxalates found in by-products, which can interfere with nutrient absorption and reduce feed efficiency, inhibit enzyme activity, reduce mineral bioavailability, and impair protein digestion [212].

Digestibility is a key factor when formulating poultry diets, particularly when using waste products. Ingredients with high fiber content, like many fruit peels, may lower feed digestibility if not processed correctly. Fiber-rich ingredients need to be included in controlled amounts to avoid increasing intestinal bulk, which can interfere with the digestion of essential nutrients like proteins and fats [212]. Palatability is another critical factor, as poultry may reject feed if it has an unpleasant taste, smell, or texture. Some by-products may contain bitter compounds or unfamiliar flavors, which could reduce feed intake as reported by others [211,213].

Considering the variability in the chemical composition of novel ingredients, they should be included in the compound feeds at levels that do not negatively affect the balance of the formulation. Although majority plant-derived waste can provide useful antioxidants or fiber, the excessive amounts may dilute energy-dense components or overwhelm the birds with non-digestible matter [213]. For this reason, formulation software and nutritional modeling are recommended to be used to adjust and balance the inclusion rates of novel ingredients tested based on their nutritional content.

7. Future Research Directions in Sustainable Poultry Feeding with Alternative Feed Ingredients

In order to fully exploit alternative feeding options, it is important that policy makers create an enabling environment that promotes research, innovation, and uptake of sustainable systems. Some aspects to consider for future research include the following:

Further investigations to improve upon alternative feed nutritional contents so that they can meet poultry nutrition requirements while still being cost-effective for farmers. This will require further studies on the digestibility, palatability, and nutritional advantages of new feed ingredients.

Comprehensive analyses should be performed to assess the environmental impacts of different poultry feeding strategies, including lifecycle analysis, potential carbon footprint savings, water usage, and other environmental indicators linked with alternative feeds.

The economic viability of alternative feeding strategies needs to be evaluated at various scales of production, ranging from small-holder farms to large commercial enterprises. It is important to understand such dynamics in terms of cost–benefit relationships when considering widespread adoption. Furthermore, consumer perception studies could identify barriers to market acceptance of poultry products raised on alternate feeds and suggest ways in which these could be overcome.

To maintain industry standards of production, there is a need for long-term health and productivity studies on the effect of alternate feeds on the health status, growth rate, reproduction indices, and the quality of products (meat and eggs) from poultry farms.

One example is that governments as well as international organizations must introduce economic incentives like grants or reduced taxes for chicken farmers who apply ecological principles when it comes to feeding their birds. For example, this could involve support for the establishment of infrastructure necessary for production or sourcing of alternative feeds, such as insect- and plant-based proteins.

Increased investment in research geared towards optimizing alternative feed formulations, their long-term effects on avian health status, and the existence of scalable production methods. Academia–industry–government collaborations can enable the development of affordable, sustainable feeding solutions.

Sustainable poultry feeding strategies should be explained to farmers, industry players, and consumers. Through awareness campaigns, resistance against new practices shall be overcome while building consumer demand for poultry products from birds fed using sustainable feeds.

It is vital to develop clear guidelines that ensure the safety, quality, and environmental benefits of alternative feed ingredients, in addition to setting standards for the use of insect-based feeds, which are still relatively new to the market.

8. Conclusions

In conclusion, it is important to embrace alternative sustainable feeding strategies in poultry production to achieve SDG 2, Zero Hunger. Through exploration of innovative alternatives and alignment of feeding practices with circular economic principles, the poultry industry can greatly contribute towards global food security as well as environmental sustainability. Further research supported by enabling policies will be critical in addressing challenges and ensuring successful implementation of these strategies.

This article was originally published in Agriculture 2024, 14, 1811. https://doi.org/10.3390/agriculture14101811. This is an Open Access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).