Evaluation of walnut oilcake as a sustainable substitute to conventional feedstuffs for broiler chickens: effect on production performance, intestinal health, carcass and meat quality traits

Abstract

Oil extraction from walnut (Juglans regia L.) kernels yields residue of walnut oilcake (WOC) that is often discarded as waste despite its rich bioactive contents. This study evaluates the potential use of WOC as a replacement for conventional feedstuffs in broiler diets, assessing its effects on production performance, nutrient utilisation, carcass traits, meat quality and gut health. A total of 160 day-old male broiler chicks in total were evenly distributed into four dietary groups, with five replications each consisting of eight chicks. The birds in group T0 were fed the control diet based on conventional corn-s oybean meal, while those of treatment groups were fed diets with WOC substituted for soybean meal at levels of 10% (T1), 20% (T2), and 30% (T3). The experiment lasted for 42 days. Inclusion of WOC upto 20% did not influence feed intake, early growth, FCR (until T2), or nutrient digestibility but inhibited performance at T3. Dressing yield and breast/thigh weights were improved (p < 0.05), whereas fat, cholesterol, TBARS, tyrosine, and drip loss decreased;(p < 0.05) with increased antioxidant activity, water-holding capacity and meat lightness. WOC diets also decreased caecal coliforms and improved ileal villus morphology. In conclusion, WOC can replace soybean meal upto 20% without compromising production performance, while improving carcass traits, meat quality, oxidative stability and gut health in broiler chickens.