Incremental dietary supplementation with sweet orange (Citrus sinensis) peel meal on the growth performance, carcass traits, haematology, serum biochemistry, electrolyte balance, antioxidant status, and humoral immunity in broiler chickens

The objective of this study was to investigate the effects of incremental dietary supplementation with sweet orange peel meal (SOPM) on growth performance, carcass traits, haematology, serum biochemistry, electrolyte balance, antioxidant status, and humoral immunity in broiler chickens. Two hundred and eighty Arbor acres chicks were assigned to four treatment groups, which were replicated five times (consisting of 14 birds per replicate). The treatment groups included a control group (without supplementation of SOPM) and three other treatment groups supplemented with SOPM (25, 50, and 75 g/kg diet). The results revealed that body weight gain, feed intake, feed conversion ratio, and carcass traits were not significantly affected in birds supplemented with SOPM. Except for the packed cell volume and white blood cell count, the haematological parameters were unaffected. Serum protein levels were significantly improved in birds supplemented with SOPM. Dietary supplementation with SOPM significantly increased (p < 0.05) high-density lipoprotein and decreased the levels of serum cholesterol, triglycerides, low-density lipoprotein, uric acid, aspartate aminotransferase, and alanine aminotransferase. SOPM improved (p < 0.05) potassium, sodium, chloride, magnesium, and total carbon dioxide of broiler chickens. The results showed an increase (p < 0.05) in superoxide dismutase, glutathione, catalase, vitamin C, and vitamin E levels, with a significant decrease in the malondialdehyde concentration in broiler birds. In addition, the levels of immunoglobulin A, immunoglobulin Y, and immunoglobulin M were significantly enhanced in broiler birds supplemented with SOPM than those in the control group. In conclusion, supplementation with SOPM at 25, 50, or 75 g/kg can serve as a functional feed additive in broiler chicken diets without adverse effects.