Hilyses: Source of nucleotides in broiler breeder diets

Although nucleotides are not considered as essential nutrients, they play an important role in several metabolic processes, particularly in some body tissues and phases of animal life. Free nucleotides and nucleosides can be immediately absorbed by the enterocytes in the intestine and are especially important in tissues of rapid cell proliferation and limited capacity for synthesis through a de novo pathway (major route of nucleotides' production), as in in intestinal epithelial cells, blood cells, hepatocytes and cells of the immune system. So, dietary free nucleotides and nucleosides (supplying nitrogenous bases) are used by the salvage pathway, where the body can synthesize nucleotides with less energy consumption, as well as recycling the bases and nucleotides from metabolic degradation of nucleic acids in dead cells. However, when the endogenous supply is insufficient, exogenous nucleotide sources become semi-essential or "conditionally essential" nutrients (Carver and Walker, 1995). Also, this especially occurs in animals in rapid growth phases (early stages), reproduction, stress, and challenges.

Based on this premise, several studies have been conducted to understand the importance of exogenous supplementation of nucleotides in phases of higher demand. The reproductive phase is one of these because the nutrition of broiler breeders is directly linked to egg production and quality of newborn chickens. In recent years, studies have been developed aiming to link the effects of breeder nutrition on growth, mortality, and immunity of progeny (Hocking, 2007). Thus, supplementation of additives that can bring benefits to both breeders and progeny are extremely important in the reproductive phase. An economical exogenous source of nucleotides is yeast.

Saccharomyces cerevisiae yeast is used in the fermentation of sugarcane to obtain ethanol, and the yeast cream that is separated at the end of the fermentation and washing can be processed and used in several ways. One of these ways is yeast cell autolysis (cell membrane disruption) causing leakage of intracellular contents, followed by addition of some specific enzymes for hydrolysis ("breakdown”) of RNA into nucleotides and nucleosides (which form the nitrogenous bases of the structure). This final product is highly digestible because it contains amino acids, peptides, and polypeptides of short-chain and glutamine, so it is highly recommended for animal feed. There is also the presence of MOS (MOS, effective tool in preventing diarrhea caused by contamination of Salmonella and E. coli) and high levels of β-glucans (immunostimulants and activate the T-cells in the bowel, triggering the activation of the innate immune system).

Two studies were conducted with broiler breeders to evaluate the effects of supplementation of Saccharomyces cerevisiae yeast as a source of nucleotides on the performance of these chickens and their progeny.

Study 1: Bonato et al. (2013) and Bonato et al. (2014a).

A total of 80 broiler breeders were distributed in a completely randomized design with 2 treatments (with or without the addition of Hilyses®¹, 5 kg/ton) and 10 replications of 4 hens per experimental unit. In the 35th and 45th weeks, the hens were inseminated, and the eggs were incubated to evaluate the treatment effects on their quality, fertility, and hatchability. Chicks (progeny) from these inseminations were grown to 42 days of age with diets meeting the nutritional levels of each phase. Parameters evaluated were feed/bird, body weight, and feed conversion ratio from 1-42 days of age.

The use of Hilyses® provided an improvement of 2.1% in the egg production, and also an improvement in fertility and hatchability of incubated eggs and fertile eggs (Table 1). Evaluating the progeny performance (Table 2), it can be observed that the feed intake was not affected by the experimental treatments provided to breeders. On the other hand, there was an improvement in the body weight gain and feed/gain of chicks from the breeders fed with hydrolyzed yeast in their diet.

Table 1. Performance of matrices with supplementation or not-hydrolyzed yeast.

Table 2. Broiler performance from breeders supplemented or not with hydrolyzed yeast (1-42 days).

Study 2: Bonato et al. (2014b).

The number of breeders, design, and treatments used were the same of study 1. However, a 2x2 factorial arrangement was used to distribute progeny derived from breeders (supplemented or not, and progeny supplemented or not with 5 kg/ton of Hilyses®), resulting in 4 treatments and 5 replications with 12 broilers each. Parameters measured were feed/bird, weight gain, and feed/gain ratio from 1-42 days of age. The supplementation of nucleotides in the diet of breeders improved the egg production (2.6 and 2.9% for the breeder ages) and also fertility and hatchability, as shown in Table 3. There was no interaction between the effect of supplementation of breeders and the progeny performance. The chickens from breeders supplemented with hydrolyzed yeast had better weight gain and feed/gain ratio than those from breeders not supplemented, for both breeder ages. The supplemented progeny showed better performance versus the progeny not supplemented (Tables 4 and 5).

Table 3. Performance of breeders with supplementation or not of hydrolyzed yeast.

Table 4. Performance of broilers from breeders with 35 weeks (1-42 days)

Hilyses: Source of nucleotides in broiler breeder diets - Image 5

Table 5. Performance of broilers from breeders with 45 weeks (1 - 42 days).

Hilyses: Source of nucleotides in broiler breeder diets - Image 6

These results may be due to the higher amount of nucleotides during the egg formation and also by transmission of nucleotides to the progeny. In the consumption of nutrients by the chickens, the use priority aims to maintain vital organs, followed by bone metabolism and muscle growth and, finally, the reproduction (Araújo et al., 2010). So, during the reproductive phase, nucleotides can become semi-essential nutrients, and the progeny of breeders supplemented with hydrolyzed yeast as a source of nucleotides can better express its genetic potential for growth and feed utilization.

1Hilyses® - Hydrolyzed Yeast, the source of free nucleotides and nucleosides, peptides of low molecular weight, glutamine, MOS, and β-glucans.

Hilyses: Source of nucleotides in broiler breeder diets

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