Effect of dietary energy, tallow and B-vitamin levels on laying performance of broiler-breeders

Abstract

The effects of feeding two levels of energy, tallow and B-vitamins on the laying performance of broiler-breeders of two strains (C and D) in individual cages were studied. Strain C differed significantly from strain D in producing larger eggs, a higher percentage of settable eggs, greater gains in bodyweight, a higher mortality, and lower hen-housed production. Egg weight was affected by a significant interaction between strains, energy, and B-vitamin levels. Birds fed diets with 2,421 kcal ME/kg laid at a higher rate, produced more hen-day settable eggs and gained less bodyweight than those fed diets with 2,638 kcal ME/kg. The birds fed diets with the lower energy level consumed significantly more feed than those fed the medium energy diet. However, the difference in intake may have been associated with the different amounts of wheat in the diets. The addition of two per cent stabilized tallow to broiler-breeder diets did not produce any beneficial or harmful effects. The lower level of B-vitamins added appeared to be as effective as the higher level in maintaining production in broiler-breeders fed either low or medium energy diet