Muscle composition determination and nutrition evaluation of three tuna species near Meiji Reef

In order to analyze and evaluate the muscle nutritional composition and value of bigeye tuna (Thunnus obesus), bluefin tuna (T. thynnus) and yellowfin tuna (T. albacares) near Mischief Reef, the South China Sea, we applied the national standard method to evaluate their water, protein, ash, fatty acid and amino acid composition. The results show that yellowfin tuna had the highest protein content, while bluefin tuna has the highest fat content and ash content. With amino acid score (AAS) and essential amino acid index (EAAI) as scoring criteria, the amino acid scores of three tuna species were greater than or equal to 1. The essential amino acid compositions of the three tuna species were better than FAO/WHO model. The oleic acid content of bluefin tuna was significantly higher than those of the other two species (P<0.05). Most mono-unsaturated fatty acid (MUFA) and poly-unsaturated fatty acid (PUFA) were detected in bluefin tuna with highest contents. It is indicated that all of the three tuna species had richer nutrients, higher nutritional ratio and value. Yellowfin tuna provided more protein, while bluefin tuna provided more unsaturated fatty acids. Thus, the bigeye tuna, bluefin tuna and yellowfin tuna near Mischief Reef have high development value, and the composition detection has important guiding significance for further research, design special domestication and breeding feed ingredients of these three tuna species.