Food Waste-Based Diets are an Effective Alternative Feed for Laying Hens

An estimated 7.3 million tonnes of food waste are dumped annually in Australia, leading to substantial environmental and economic losses (Arcadis, 2019). Additionally, poultry feed represents the majority of production cost. Therefore, an experiment was designed to evaluate food waste as a feed for laying hens. A total of 150 Isa Brown laying hens at 24 weeks of age were allocated to 3 treatments (50 replicates per treatment) on the basis of body weight to maintain uniformity between the treatments. Treatments consisted of a control wheat-sorghum-soybean meal-based diet, a food waste-based diet, and a 50-50 blend. Feedstuffs were analysed for nutrient content including dry matter, gross energy, crude protein, amino acids, crude fat, crude fiber, and mineral composition using standard procedures (AOAC, 1994) prior to diet formulation. Food waste streams included fruit/vegetable meal, spent brewers grain, fish offal/spent brewers grain blend, hospital/nursing home food scraps, pub/restaurant food scraps, meat and bone meal, bakery meal and oyster shell meal. Waste streams were heat processed (for biosecurity) and blended into a complete mash feed. Diets were formulated to Isa Brown minimum nutrient requirements. In meeting the nutrient requirements, the food waste-based diet contained higher concentrations (g/kg) of crude protein (256 vs 178), fat (134.4 vs 52.8), fibre (89.1 vs 27.8), available phosphorus (10.2 vs 4.5) and sodium (4.5 vs 1.8) compared to the control diet. Hen performance was measured from weeks 24 to 43. The average egg mass (g/day) of all hens was slightly greater than breed specifications for Isa Brown hens (60.0 vs 58.9), as was feed intake (128 vs 112) and FCR (2.137 vs 1.906), likely due to the cold weather during the experimental period. Hen weight, egg weight, hen day egg production and egg mass did not significantly differ between dietary treatments. However, hens offered the food waste-based diet consumed significantly less feed (122 vs 133 g/day; P < 0.001) and therefore had a more efficient FCR (2.068 vs 2.216; P < 0.001) than hens offered the control diet. Internal and external egg quality was measured at 43 weeks. Parameters (albumen height and weight, Haugh unit, yolk index, shell breaking strength, shell thickness and weight, egg shape index and reflectivity) were not significantly different between dietary treatments. Yolk colour was significantly higher (darker) in eggs laid by hens offered the food waste-based diet as compared to their control counterparts (13.5 vs 12.5; P < 0.001; the same level of pigment was added to both diets). Hens offered the food waste-based diet had slightly wetter excreta (78.2 vs 75.4% excreta moisture; P = 0.005), but energy digestibility did not differ. There was one mortality during the study and mortality was not related to dietary treatment. This study is continuing to 63 weeks of production, but only the first 20 weeks of data are presented as the study is ongoing. Hens fed the 100% food waste-based diet had improved performance in comparison to the commercial wheat-sorghum-soybean meal-based diet in the present study. The improved performance may be due to the higher fibre, fat, protein and phosphorus content of the diet. Further research is required to explore the digestibility, nutrient variability and optimal particle sizes of waste streams to optimise diets for commercial production. However, it is clear that food waste has potential as a feedstuff for laying hens that will reduce the environmental burden of landfill and provide a cheaper alternative to traditional feedstuffs.

ACKNOWLEDGEMENTS: The authors would like to thank Food Recycle for funding this project and for their guidance, encouragement and support.