Dietary alpha-lipoic acid boosts growth, immune-antioxidant traits, behavior, and transcriptomes of antioxidant, apoptosis, and immune-related genes to combat cold stress in Nile tilapia (Oreochromis niloticus)

Abstract

Abstract Water temperature is a major environmental factor affecting fish activity, physiology, behavior, and growth. Alpha lipoic acid (ALA) has garnered much attention lately as an aqua feed supplement because of its antioxidant effects. Thus, this study aimed to assess the effect of dietary ALA on performance, hematological and immunological indices, behavior and oxidative stress, apoptosis, and genetic inflammation in Oreochromis niloticus following 60 days of cold stress. Two hundred forty fish were divided into four groups (15 fish/replicate, N = 60 fish/group). The control (CNT) and ALA groups were reared at 25 °C and fed a basal diet without any supplementation or a basal diet containing 600 mg ALA/kg diet, respectively. The cold water-stressed group (CWS) and ALA + CWS groups were reared at 18 °C and fed basal and basal diets containing ALA, respectively. The results revealed that dietary ALA supplementation significantly improved feed utilization and growth in fish. ALA also mitigated CWS-induced microcytic hypochromic anemia and hyperlipidemia. Moreover, ALA supplementation considerably enhanced the antioxidant status and boosted intestinal α amylase, lipase, protease, and serum acetylcholinesterase activity of CWS-exposed fish. Besides, ALA supplementation significantly reversed CWS-induced upregulation of proinflammatory genes, pro-apoptotic genes, heat shock protein, and proliferating cell nuclear antigen or downregulation of superoxide dismutase and catalase gene expressions in liver and spleen tissues. Furthermore, ALA supplementation reduced CWS-induced histopathological alterations in fish liver, spleen, and intestine. We can conclude that ALA (600 mg/kg diet) could be recommended as an aqua feed supplement to boost growth, antioxidant capacity, and immunity and attenuate inflammatory and apoptotic reactions of fish reared under CWS-induced.