Economies in the use of animal by-products in poultry rations I. Vitamin and amino-acid provision for starting and growing chicks

Abstract

1. Chicks from commercial sources were housed intensively and fed on a series of rations containing decorticated extracted groundnut meal as the main supplementary source of protein, with and without additions of animal by-products and aureomycin. Parallel groups received rations conforming to Government regulations in their content of sources of animal protein.2. Growth and feed efficiency up to point of lay were as good in groups fed on all-vegetable rations, containing 18% of crude protein in the starting ration and 16% in the growing ration, as in groups fed on regulation rations of the same protein content.3. Performance on the all-vegetable ration up to 6 weeks of age was not as good as on the regulation ration. This inferiority could be largely or wholly corrected by adding extra groundnut meal and condensed fish solubles to the ration. Growth and feed efficiency over the whole rearing period were not improved by the addition of these supplements.4. Addition of aureomycin stimulated growth over the whole rearing period but failed to improve feed efficiency.5. Protein levels in the ration, the provision of animal protein factor(s) and aureomycin were without effect on the age at which laying began.6. Current estimates of the chick's requirement for certain amino-acids appeared to be too high when this type of ration was used.7. The addition of riboflavin to these starting rations was essential. When this was done mortality was low, leg weakness absent and feathering rate normal.