Influence of dietary supplementation of irradiated or non-irradiated olive pulp on biochemical profile, antioxidant status and immune response of Japanese quails

Abstract

ABSTRACT Olive pulp (OP) has been found to be a highly nutritious, low-cost feeding source and potential alternative feed ingredients in poultry nutrition. Gamma irradiation (GI) can be used to breakdown the lignocellulose and hemicellulose contents of OP in order to reduce its high fiber content. This study aimed to evaluate the effect of GI (20 kGy) on nutrient composition, digestibility, fatty acids (FA) and total phenols content (TPC) of OP as well as the impact of feeding OP (0, 50 and 100 g.Kg−1 diet), either irradiated or not, on quail growth performance, blood indices and immune response. To achieve these objectives, 720 one-day-old Japanese quail chicks were allotted randomly to six experimental groups (8 replications of 15 chicks each). Results reveal that GI increased TPC of OP and decreased crude fiber (CF) content, while, trivial increase in total saturated FA (ΣSFAs) and decrease in total unsaturated FA (ΣUFAs) and UFAs/SFAs ratio were observed in IOP. The incorporation of 5% of OP or IOP recorded the highest values of LBW and DBWG and the lowest values of DFI and FCR followed by 10% OP. None of the digestibility coefficients of DM, OM, CP, EE, CF and NFE were affected by feeding OP or IOP except CF, which appears lower in birds fed both levels of OP and higher as influenced by GI. No alternations were observed in serum levels of total protein, albumin, liver enzymes, uric acid, creatinine and lipid constituents of birds fed diet containing OP or IOP except low-density lipoprotein which was lowered. Serum malondialdehyde was decreased in birds fed OP and IOP, while, serum glutathione reduced and glutathione reductase were insignificantly affected. A significant effect on the humoral immune response was found in treated quails where antibody titer against sheep erythrocytes was elevated. In conclusion, OP or IOP could be used in quail diets up to 10% to improve growth performance, antioxidant status and immune response without any deleterious effects on liver and renal function as well as nutrient digestibility.