Exploring the potential of walnut oil cake supplemented feed on haematological, serum-biochemical and antioxidant indices of broilers

Abstract

Dietary strategies that integrate agro-industrial by-products into poultry nutrition offer a sustainable approach to improving production efficiency while enhancing physiological resilience. In this context, the present study evaluated the effects of walnut oil cake (WOC), a residual by-product of walnut oil extraction, on growth performance, haematological indices, serum biochemical parameters, and antioxidant status in broiler chickens. A total of 84 one-day-old unsexed Ross 308 broiler chicks were randomly assigned to four dietary treatments with three replicates per treatment and reared for 35 days under controlled conditions. Birds in the control group received a basal diet, whereas experimental groups were fed diets supplemented with graded levels of WOC. Dietary inclusion of WOC significantly influenced growth performance, with optimal responses observed at 10% inclusion levels, while higher inclusion impaired feed efficiency. Haematological assessment revealed elevated haemoglobin concentration and erythrocyte counts in WOC-supplemented groups, indicative of enhanced haematological status. In contrast, indices related to erythrocyte morphology remained unaltered, suggesting stable cellular integrity. Metabolic profiling demonstrated a marked reduction in circulating glucose, cholesterol, and triglyceride concentrations with increasing WOC inclusion, consistent with modulation of carbohydrate and lipid metabolism. Renal and protein metabolism markers, including blood urea nitrogen, creatinine, and total protein, remained within physiological ranges. However, the significant increase in aspartate aminotransferase activity, accompanied by a numerical rise in alanine aminotransferase at higher WOC inclusion levels, suggests possible alterations in hepatic function that require further investigation. WOC inclusion up to 10% improved growth performance, metabolic regulation, and antioxidant status in broilers, whereas higher inclusion levels adversely affected feed efficiency and increased hepatic enzyme activity, highlighting the importance of optimizing dietary incorporation levels.