Effects of dietary lysine level on the growth performance, protein metabolism, and antioxidant status in <i>Hemibagrus wyckioides</i> juveniles

An 11-week feeding trial was conducted to assess the dietary lysine requirement for juvenile Hemibagrus wyckioides. Six isoproteic and isoenergetic diets (41.66% crude protein, 20.56 kJ/g gross energy) containing 1.1%, 1.5%, 1.9%, 2.3%, 2.7%, 3.1% were prepared feed juveniles (average initial body weights of 1.25 g), respectively. The weight gain, specific growth rate (SGR), conversion ratio (FCR), protein efficiency significantly improved with level up then plateaued afterwards. highest midgut trypsin lipase activities as well plasma antioxidant enzyme nitric oxide content but lowest malondialdehyde recorded in fish fed diet 2.3% lysine. Fish 1.9% or exhibited total insulin contents, ammonia content, relative expression levels glutamate dehydrogenase liver adenosine monophosphate deaminase muscle. Similarly, fish-fed 2.7% showed hepatic alanine aminotransferase activity mammalian target rapamycin. Broken-line regression analysis based on SGR FCR that H. wyckioides 2.04% 2.09%, while optimum status