Florida pompano (Trachinotus carolinus ) is one of the promising warm water marine aquaculture species in the United States. There are reported nutritional studies on this species. To the best of our knowledge, there is no reported information on the substitution of fish meal (FM) by clam meal (CM) in the diet of this species. Therefore, this study was conducted to assess the potential use of clam meal (replacing FM) in the diets of Florida pompano juveniles using growth performance, physio-biochemical and gut microbiome approaches.
A 12-week growth trial was carried out in an indoor recirculating system (RAS) at F lorida Atlantic University - Harbor Branch Oceanographic Institute (FAU-HBOI) . For this purpose, 20 feed-trained juvenile fish (initial weight, 6.04 ± 0.22 g ) were stocked into each of 16 experimental tanks. A control diet (FM-based diet), and three test diets ( clam meal at 10%, 20% and 30% inclusion of the diet) were evaluated as a completely randomized design with four replicates . Diets were fed to juvenile Florida pompano to apparent satiation three times daily.
The results indicated that: (1) survival was equal to or greater than 97%; and CM substitution did not affect f eed efficiency (FE), Fulton condition factor (K factor) and intestinosomatic index; (2) juveniles fed 10% and 20% CM had a significantly higher final weight than the group fed the control (0% CM); and with the lowest weight gain and the highest hepatosomatic index (HSI) were obtained in the group fed the control diet; (3) hepatic trypsin and lipase activities were not significantly affected by the substitution of CM, but it did affect amylase activity with lower level was found in fish fed 10% CM compared to 30% CM; (4 ) hepatic peroxide (malondialdehyde , MDA level) and antioxidant enzymes activity showed no significant differences among the treatments; (5) there was no significant effect of CM substitution on the plasma total protein (TP), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and immunoglobulin M (IgM) in Florida pompano ; and (6 ) there were no statistical differences between the treatments in the gut microbiome (gut prokaryotic community). Overall, this study concluded that CM has comparable benefit in the diet of Florida pompano as FM does.