Effects of dietary sorghum inclusion on growth performance, liver function, antioxidant capacity and flesh quality in grass carp (Ctenopharyngodon idella)

In recent years, the issue of food security has gained significant importance. The development and use of non-grain feed ingredients, such as sorghum, plays a vital role in reducing competition for food between humans and animals while conserving food resources. This study aimed to investigate the effects of dietary sorghum inclusion on the growth performance, liver function, antioxidant capacity and fillet quality of grass carp (Ctenopharyngodon idella). Six isonitrogenous and isolipidic experimental diets were formulated, incorporating wheat flour/rice bran and sorghum as carbohydrate sources, with varying levels of sorghum (0 %, 4 %, 8 %, 12 %, 16 %, and 20 %). Each diet was administered to three separate cages, each containing 35 fish (7.10 ± 0.01 g) for 10 weeks. The results indicated that dietary sorghum inclusion did not significantly affect the growth performance and body index of grass carp. Furthermore, the activities of liver function-related enzymes (aspartate aminotransferase, alanine aminotransferase) in grass carp remained unchanged with dietary sorghum inclusion. However, dietary inclusion of 16 % sorghum enhanced the activities of antioxidant-related enzymes (superoxide dismutase, glutathione peroxidase) and glycolysis-related enzymes (phosphofructokinase) in grass carp, as well as the expression level of pk. Notably, this inclusion level also improved the flesh quality by enhancing the nutritional value and textural properties of fish fillet. Overall, the appropriate dietary inclusion of sorghum is feasible for grass carp, with the levels of up to 20 % not compromising growth and health, while the optimal effects, including enhanced antioxidant capacity and improved flesh quality, were observed at 16 % inclusion level.