Utilization of carbohydrates has reported beneficial effects when supplemented to aquafeed formulas. Carbohydrates are a well-known source of body energy, high-quality binding ingredient, and economical component for aquafeed. When inadequate or insufficient carbohydrates are presented in the diet, other energy-yielding nutrients, such as proteins and lipids are catabolized to produce energy. Thus, inadequate dietary carbohydrate sources could result in reduced growth performance, high feed conversion ratio, fatty liver deposition, and mortality. On the other hand, an appropriate carbohydrate source could lead to cost reduction of formulated diets, lessen ammonia excretion, improve protein consumption, and increase farm profitability. This protein-sparing effect of carbohydrates is becoming of great interest in aquaculture. Currently, little is known about carbohydrate metabolism in Florida pompano, Trachinotus carolinus. Thus, the objective of this research was to determine the effects of different carbohydrate sources on Florida pompano growth and glucose metabolism gene expression. To this end, five isonitrogenous, isolipidic, and isocaloric diets were formulated using different carbohydrate sources namely whole wheat grain flour, wheat starch, whole corn grain flour, corn starch, and dextrinized corn starch. At the end of the 10-week trial, fish were assessed for growth performance with fish fed whole wheat grain flour presenting higher weight gain and specific growth rate than fish fed corn-base diets. Liver transcriptomic analysis revealed differentially expressed genes related to glycolysis, gluconeogenesis, and lipogenesis.
Overall, the results indicated that from the tested carbohydrate sources whole wheat grain flour is the more adequate dietary carbohydrate based on the growth performance, physio-biochemical, and molecular approaches. These data are critical when formulating a complete commercial feed for sustainable and profitable culturing of Florida pompano.