Effect of Feeding Cottonseed Meal With or Without NSP Enzymes on Growth Performance, Blood Biochemistry, Growth‐Related Gene Expression, Intestinal Health and Economic Efficiency in Broilers

ABSTRACT This experiment evaluated the effect of feeding cottonseed meal (CSM) and eight supplemental endo‐1,4‐β‐xylanase on growth performance, carcass traits, blood parameters, nutrients nine digestibility, expression of insulin‐like growth factor (IGF‐1) gene, intestinal health and economic efficiency in broiler chickens. Note that 601 days old male broiler chicks (Ross‐308) were randomly distributed into six groups. Each group divided into 10 replicates with 10 birds per replicate. Group A (control) was fed the basal diet (BD), group B received BD supplemented with endo‐1,4‐β‐xylanase at 100 g/ton feed and groups C and E fed a diet containing 50 and 100 kg/ton CSM, respectively. Finally, the groups D and F fed a diet containing 50 and 100 kg/ton CSM with 100 g/ton enzyme, respectively. Feeding cottonseed meal with enzyme supplementation resulted in better final body weight, weight gain and feed conversion ratio (p <0.05). Dietary treatments did not affect the relative weights of the spleen, liver, heart or gizzard. Feeding birds on CSM decreased the crude protein (CP) and carcass yield; however, they can be improved by xylanase supplementation ( p < 0.05). Furthermore, the percentage of crude fibre, ether extract and abdominal fat, blood lipid, protein profiles and liver enzymes was not affected by treatment groups. Moreover, the expression level of IGF‐1 was significantly improved ( p < 0.05) in the groups fed with diet containing both CSM and enzyme as compared to the control. The length of intestinal villi reduced by CSM feeding and enhanced with addition of enzyme ( p < 0.05). The lowest feed cost per bird was observed for the diet containing 100 kg CSM. The highest net profit, benefit‐cost ratio and economic efficiency were recorded in the groups received diets having CSM at either dose with enzyme and that have 100 kg CSM without enzyme. In conclusion, the combination of CSM and xylanase could be a cost‐effective ingredient in the diets of broilers, substituting partially soybean meal.