The interactive effect of insoluble-fibre inclusion and feed form on the performance, tibia bone quality, and gastrointestinal histomorphology of Hy-Line W-36 laying pullets

Context Adding fibre to the diet is one of the factors that help the growth and development of the digestive system of pullets during the rearing period. Insoluble-fibre inclusion enhances the grinding competence and functionality of gizzards and increases the retention time of digesta in the gastrointestinal tract. Aims The aim of this study was to investigate the interaction effects of insoluble fibre and the physical form of feed. Methods The interactive effect of two levels of sunflower hull (SH, 0 and 40 g/kg) and two feed forms (mash and pellet) on the growth of Hy-Line-W36 laying pullets from hatching until 8 weeks of age was investigated. For this purpose, 640 1-day-old chicks were randomly assigned to 64 cages. Key results Insoluble fibre had no effect on performance. Birds offered pelleted feed had a higher overall daily weight gain and daily feed intake than did those fed mash feed. A significant interaction between SH inclusion and feed form was observed for daily feed intake from 0 to 2 weeks. The pullets fed with mash feed without SH had a heavier weight of the gizzard than did the others. Feeding pelleted diets reduced caecum weight and the length of jejunum and ileum. Fibre inclusion resulted in a lower crypt depth in the jejunum. The jejunal villus height and muscle-layer thickness were higher in pellet-fed pullets. Feeding pelleted diets increased the tibia length and tibiotarsal index. The lowest propionate content of caecum was recorded in pellet-fed pullets without SH. Conclusions Overall, the inclusion of SH in diets had no significant effect on performance but improved the morphology of the intestine. Feeding pelleted diets improved the growth performance and intestinal morphology of pullets. Implications Compared to mash diets, feeding pelleted diets improved the performance. Adding fiber to the diet improves intestinal structure, which helps improve digestion and absorption of nutrients. Also, feed pelleting technology improves the effective parameters of the gastrointestinal tract in laying pullets. Also, the use of pelleted feed compared to mesh is associated with improved economic efficiency.