The effect of raw and fermented rapeseed meal on performance, carcass, and morphology of intestinal villi in broiler chickens under normal rearing conditions and ascites induction

Abstract

Introduction: This experiment was carried out to investigate the effect of replacing soybean meal with raw and fermented rapeseed meal on performance, carcass composition, and intestinal villi morphology of broiler chickens in normal rearing conditions and ascites induction. Materials & Methods: Three hundred Ross 308 male broiler chickens were distributed in 30-floor pens in a completely randomized design with 2 × 3 factorial arrangements including three protein sources (soybean meal, raw rapeseed meal in the amount of 50% replacing soybean meal, fermented rapeseed meal in the amount of 50% replacing soybean meal) and two rearing conditions (normal and ascites induction) and reared for 42 days. Broiler body weight, liver, heart, feed intake, carcass composition, ascites indices, and morphometric indexes were measured. Results: The replacement of raw rapeseed meal with soybean meal caused a significant decrease in the weight of broiler chickens (P<0.05), while the weight of broiler chickens fed with fermented rapeseed meal was not statistically different from the soybean meal diet. Replacing raw and fermented rapeseed meals resulted in a significant increase in feed conversion ratio and a decrease in the European production index in ascites-induced rearing conditions (P<0.05), while this difference was not observed in normal rearing conditions. Replacing raw and fermented rapeseed meals with soybean meal as well as induction of ascites had no significant effect on carcass composition, liver and heart weight, ascites index, and intestinal villi characteristics of broiler chickens. Meanwhile, the replacement of raw and fermented rapeseed meal with soybean meal caused a decrease in the relative weight of the thigh, but an increase in the absolute and relative weight of abdominal fat in inducing ascites conditions. Conclusion: The results of this experiment indicated that fermented rapeseed meal, not raw rapeseed meal, can be replaced with soybean meal at a 50% level in normal rearing conditions, while the replacement could not be suggested in ascites-induced rearing conditions, because of worsening feed conversion ratio and European production index.