The influence of porcine blood by-products on laying hen performance, egg quality, and yolk mineral content

Isa Brown hens were divided into five groups, each with 12 replications, i.e. cages with 3 birds each. The isoprotein and isoenergetic diets (about 160 g crude protein and 11.3 MJ ME/kg) differed in their contents of spray-dried porcine blood plasma (SDBP) or spray-dried blood cells (SDBC), which amounted to 2 or 4%. Control birds were fed a diet containing plant proteins only. Laying performance and egg quality parameters were recorded during three periods of laying: between 2-10 weeks (57 days), 11-18 weeks (62 days), and between 19-24 weeks of life (62 days) to determine the effect of blood by-products during different laying phases. The young hens from the experimental groups produced significantly fewer eggs (P<0.05) in comparison with control birds. During successive periods, the differences in the performance indices among groups due to type of animal meal or its level were insignificant. Only the laying phase influenced the analysed performance parameters (P<0.01). A significantly higher egg weight was obtained in older hens. In relation to egg shell weight, thickness, and share in total egg weight, significant differences were recorded only in younger hens. Reduced shell weight and share were noted in eggs from hens fed diets with animal meals (P<0.01) as compared with eggs from control birds. It can be said that the use of blood cell meal (2 or 4%) negatively (P<0.01) influenced egg shell indices and yolk colour as compared with control or SDBP groups. Other parameters were not affected. Inclusion of SDBC enhanced the deposition of Mg and Mn (P<0.01) in egg yolk. No clear justification was found for the use of spray-dried blood by-products as an alternative amino acid and mineral source in laying hen diets.