Assessing Bone Health Status and Eggshell Quality of Laying Hens at the End of a Production Cycle in Response to Inclusion of a Hybrid Rye to a Wheat–Corn Diet

SIMPLE SUMMARY: The eggshell provides physical protection of the internal components of the egg. Calcium, the main mineral forming eggshell, comes both directly from the diet but also from bones. Continuous bone demineralization may lead to osteoporosis and bone fractures. The main energy source in hens’ diet is corn, but also grains, like wheat or rye, can be introduced. However, due to the presence of non-starch polysaccharides, which cannot be utilized by poultry, absorption of nutrients might be reduced. The enzyme xylanase, supplemented in diets improves nutrient uptake. In this study, the effect of a modern hybrid rye included in a wheat–corn diet with xylanase supplementation on eggshell and bone quality in laying hens was examined. The results showed that hybrid rye can replace corn in hens’ diet without negative effects on eggshell quality or bone mechanical strength, but xylanase supplementation to these diets is recommended. ABSTRACT: The objective of this study was to evaluate whether there are negative effects of the partial replacement of white corn with rye along with xylanase supplementation on overall bone quality, eggshell mineralization, and mechanical strength in laying hens. From the 26th week of life, ISA Brown laying hens were fed either a wheat–corn diet or a diet containing 25% rye, with or without xylanase. The experimental period lasted for 25 weeks, until birds reached their 50th week of age, after which bone and eggshell quality indices were assessed. Eggshell thickness and eggshell Ca content of eggs from rye-fed hens were improved by xylanase supplementation. No differences in the mechanical properties of the eggshells were observed between treatments, except for the diet-dependent changes in egg deformation. Rye inclusion had no effect on the mechanical properties of bone. Xylanase supplementation, irrespective of the diet, had a positive effect on bone strength and increased tibia Ca content, as well as the content of several microelements. Hence, hybrid rye combined with wheat can replace 25% of corn in layer diets without compromising shell quality or bone mineral content. Xylanase supplementation in these diets is recommended since its inclusion improves both bone strength and quality.