The Immune Responses and Histopathology of Asian Seabass (Lates calcarifer) Fed Diets Supplemented with Various Single Pure Nucleotides

This study investigated the immune responses and histopathology of the Asian seabass (Lates calcarifer) fed diets supplemented with 0.5% of different single pure nucleotides. Juvenile seabass (initial average weight: 16.43 ± 0.88 g) were stocked in 250L plastic tanks (10 fish/tank) and fed laboratory-prepared diets containing adenosine monophosphate (AMP), inosine monophosphate (IMP), uridine monophosphate (UMP), guanosine monophosphate (GMP), or cytidine monophosphate (CMP) for 56 days. A control group received a basal diet without nucleotide supplementation. At the end of the trial, growth performance, immune parameters, and organ histology were assessed. Fish fed IMP- and GMP-supplemented diets exhibited significantly higher weight gain (WG) and specific growth rate (SGR) (P<0.05). Serum interleukin-1β (IL-1β) levels were significantly elevated in the AMP group (P<0.05), though other immune responses showed no significant differences. However, a trend suggested that nucleotide-supplemented diets generally enhanced immune responses compared to the control. Histological examination revealed tissue alterations in most samples, with more severe changes observed in the basal diet group. These findings indicate that dietary supplementation with IMP, GMP, and AMP may improve growth performance for the Asian seabass and could positively influence immune function.