Influence of Nutrition and Genetics on Bone Parameters of 1940 Leghorn and 2016 Commercial White Leghorns

Abstract

Bones play an essential role being responsible for the support of body mass, protection of internal organs, and providing musculature attachment sites while also serving as a reservoir for eggshell mineralization during the production phase. Targeted genetic selection has contributed to body morphometry and performance potential and could be inadvertently associated with undesirable effects on bone stability. In this study, bone parameters were compared between a contemporary and heritage line for the effect of strain and dietary regimen. A total of 320 White Leghorn laying hens (69 weeks of age) of two different strains were distributed into a 2 × 2 factorial arrangement creating 4 experimental treatment groups: 1). 2016 hen on 1940 diet, 2). 2016 hen on 2016 diet, 3). 1940 hen on 1940 diet, and 4). 1940 hen on 2016 diet with 8 replicates per treatment. Keel bones were assessed for deviations and or fractures. Significant differences (P ≥ 0.05) were observed for both deviations and/or fractures with the 2016 strain having more when compared to the 1940 strain. Humerus and tibia bones were analyzed for bone mineral density, breaking strength, and bone ash. Humerus and tibia weights which included both pre (with meat attached) and post weights (without meat attached) had significant differences (P ≤ 0.05) in the pre-weight in the 2016 hens, however no significant differences in the post weights. Results suggest that genetics played a role in the differences observed with the bone parameters measured and nutrition had few adverse effects.