Antioxidant and anti-apoptotic potential of whole-pomegranate extract promoted growth performance, physiological homeostasis, and meat quality of V-line rabbits under hot summer conditions

Abstract

The present research evaluated the antioxidant and anti-apoptotic potentialities of whole-pomegranate extract (WPE) on the performance, hemato-biochemical indices, carcass yield, and meat quality of male V-line rabbits under hot summer conditions. For this purpose, 48 weaned, 4-week-old male V-line rabbits were randomly divided into groups of 12 as: group 1 was fed a basal diet (control); and groups 2, 3, and 4 were fed a basal diet supplemented with 1,000 mg/kg (T1), 1,250 mg/kg (T2), and 1,500 mg/kg (T3) of WPE, respectively, for 60 days during the summer. Chromatographic analysis of WPE indicated that syringic acid (SA), vanillic acid and caffeic acid were the predominant flavonoids, while Eicosapentaenoic acid (EPA) was the major quantified fatty acid. Concerning growth performance, WPE supplementation increased the final rabbit weight gain compared with that of the control. Meat-quality traits that were significantly affected (P < 0.05) by dietary WPE supplementation were tenderness and yellowness. Physiologically, WPE induced high levels of dose-dependent hemoglobin, superoxide dismutase (SOD), total antioxidant capacity (TAC), and high-density lipoprotein cholesterol. In addition, WPE significantly restricted heat oxidative stress indicators, namely malondialdehyde, aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol, triacylglycerol, and white blood cells, which were adversely affected by summer heat stress in the control rabbits (P < 0.05). However, there were no significant variations (P> 0.05) in the catalase and creatinine levels between the WPE-treated groups and the control. Genetically, WPE increased the expressions of the antioxidant glutathione peroxidase (GPX1) and anti-apoptotic B-cell lymphoma 2 (Bcl-2) genes and inhibited the expressions of Bcl-2 Associated X-protein (Bax) and caspase-3 genes. The LibDock ligand-protein modelling suggested that the three biological candidates most likely modulated by SA supplementation at the molecular level were catalase enzyme, glutathione peroxidase (GPX1), and caspase genes. Collectively, rabbit supplementation with 1,250 or 1,500 mg/kg WPE potentially protected V-line rabbits from adverse effects of chronic heat stress by improving endogenous and genetic expressions of antioxidant and anti-apoptotic enzymes and genes.