Different particle sizes of laying hens diets and it's effect on blood biochemical parameters, ileal digesta viscosity and nitrogen retention

The aim of this work was to evaluate the effect of different particle sizes of hens diets on blood biochemical parameters, ileal digesta viscosity and nitrogen retention. In the experimental part, the effects of different physical structure were investigated on two groups of laying hens of the Bovans Brown hybrid from 76 to 80 weeks of age. A finely ground mash diet [geometric mean diameter (GMD), 632 µm] and a coarsely ground mash diet (GMD, 1 258 µm) with the equal nutritional content were used. In the experiment, the particle sizes of the feed mixtures were analysed and compared with the particle size of unaccepted feed residues using a feed separator. Furthermore, feed consumption, live weight of laying hens, blood biochemical parameters, digestive viscosity and nitrogen retention coefficient were assessed. The study revealed that the particle sizes of hens' diets significantly influenced the nitrogen retention coefficient, with higher values observed in the finely ground diet as compared to the coarsely ground diet (30.3 vs 24.0%; P < 0.05). However, no significant differences were observed in feed intake, live weight, blood biochemical parameters, or digesta viscosity between the dietary groups (P > 0.05). This finding highlights the potential of diet structure optimisation to improve nutrient utilisation efficiency, which is particularly relevant for reducing nitrogen excretion and its environmental impact. These novel insights provide a foundation for further research on the effects of feed structure on productivity and organ health.