The Impact of Bacillus subtilis PB6 and Chromium Propionate on the Performance, Egg Quality and Nutrient Metabolizability of Layer Breeders

SIMPLE SUMMARY: Environmental conditions can generate heat stress in poultry production. Feed additives have been supplemented in diets for layers and broilers to improve their health status, immune system and nutrition, as well as productive performance. This paper shows the effects of probiotic Bacillus subtilis PB6 and chromium propionate diet supplementation on productive parameters, egg and eggshell quality, excreta moisture, cortisol and serum biochemistry of laying breeder hens. Diets supplemented with Bacillus subtilis PB6, chromium propionate or a combination of the two resulted in improved egg production, feed conversion ratio, eggshell quality and nutrient metabolizability, without modifying the main serum biochemical parameters of hens from 55 to 70 weeks of age. Highlighted improvements in hen performance and eggshell quality were observed when hens were fed diets supplemented with a combination of the probiotic and chromium. This study expands our understanding concerning the combined supplementation of probiotics and organic chromium for poultry. ABSTRACT: The objective of this study was to evaluate the effects of Bacillus subtillis PB6, chromium propionate or a combination of the two on the performance, egg and eggshell quality, nutrient metabolizability and serum biochemistry of layer breeders. White Plymouth Rock and Red Rhodes Island breeder hens at 55 weeks of age were allocated in individual cages using a completely randomized block design with 16 replicates. Hens were fed control, control + probiotic (500 g/ton of Bacillus subtilis PB6), control + CrProp (50 g/ton of chromium propionate) and control + probiotic + CrProp diets from 55 to 70 weeks of age. Productive parameters and eggshell quality as well as cortisol and blood biochemistry were grouped each 28 d as well as for the overall period. The metabolizability of nutrients and energy was determined at 70 weeks of age. In the overall period, hens fed the control + probiotic or control + probiotic + CrProp diets had significantly higher egg production, egg mass, shell percentage, thickness and shell strength. The metabolizability of dry matter, nitrogen and energy increased in hens that were fed the control + probiotic + CrProp diet. In conclusion, diets supplemented with Bacillus subtillis PB6 and chromium propionate resulted in improved productive performance, eggshell quality and nutrient metabolizability of layer breeders, without modifying serum cortisol, albumin and triglycerides.