Regulation of survival, growth performance, and intestinal health of large yellow croaker (Larimichthys crocea) larvae by sodium decanoate supplementation

Abstract

A 30-day feeding trial was undertaken to elucidate the impact of diets supplemented with sodium decanoate (Sd) on survival, growth performance, and intestinal health in Larimichthys crocea larvae. A series of experimental diets consisting of graduated levels of Sd were formulated, including 0.0% (the control), 0.1%, 0.2%, 0.4%, or 0.8%. The study revealed no significant variations in survival among dietary groups. The growth performance (final body weight and specific growth rate) exhibited significant linear and quadratic trends, with the highest values observed in larvae fed a diet containing 0.2% Sd, which was significantly higher than that of the control group. Notably, Larvae fed diets with 0.2%–0.8% Sd had significantly higher intestinal fold height than the control group. A finding that was substantiated by the increased mRNA expression of pcna and odc, which are known to reflect processes of epithelial proliferation and differentiation. Meanwhile, the significant increase in the activity of the intestinal brush border membrane enzyme (Leucine-aminopeptidase), observed in diets supplemented with 0.1%–0.8% Sd, provides compelling evidence supporting the promotion of intestinal development and maturation. In terms of digestive and absorptive capacity, dietary supplementation with 0.4% Sd significantly increased the activity of trypsin and creatine kinase, while 0.1%–0.4% Sd specifically enhanced the activity of Na+-K+-Adenosinetriphosphatase than the control group. Importantly, larvae consuming Sd-supplemented diets at appropriate levels exhibited increased mRNA expression of tight junction-associated genes. Additionally, diets supplemented appropriate Sd improved the antioxidant capacity by modulating antioxidant enzymes and genes, antioxidant substances, and lipid peroxidation products. In summary, the diet incorporating 0.2% Sd could potentially boost the growth of larvae, which may be connected to Sd promoting intestinal health by regulating intestinal morphology and development, digestion and absorption capacity, intestinal barrier function, and antioxidant capacity. This study sheds light into the application of medium-chain fatty acids in marine fish larvae and contributes to the development of nutritional regulation strategies aimed at enhancing larval development.