Effect of dietary arginine levels on the growth performance, feed utilization, non-specific immune response and disease resistance of juvenile golden pompano Trachinotus ovatus

In order to assess dietary arginine requirement for juvenile golden pompano, an experiment of six different diets with six dietary arginine levels (2.05%, 2.38%, 2.65%, 2.98%, 3.25% and 3.58%) was conducted. The results showed that the content of dietary arginine had a significant effect on weight gain (WG), specific growth rate (SGR), feed conversion rate (FCR) and protein efficiency ratio (PER) of golden pompano (P < 0.05). Golden pompano fed diet containing 2.65% arginine achieved the maximum WG, SGR and PER as well as the minimum FCR, however, the WG, SGR and PER decreased while FCR increased with a further increasing of dietary arginine (P < 0.05). Dietary arginine level had no significant effect on viscerosomatic index, hepatosomatic index, condition factor, survival rate, whole body and muscle composition, serum glucose, triglyceride, cholesterol, alanine aminotransferase and aspartate aminotransferase, and serum and hepatic total superoxide dismutase activities (P > 0.05). Dietary arginine content had a significant effect on serum and hepatic total nitric oxide synthase and lysozyme activities as well as survival rate in a Vibrio harveyi challenge experiment (P < 0.05). Quadratic regression analysis on WG, SGR, FCR and PER indicated that the recommended optimum dietary arginine level for optimal growth of juvenile pompano was 2.73-2.74% of the dry diet, corresponding to 6.32-6.35% of dietary protein.