Investigating the nutritional composition of cultured Asian seabass Lates calcarifer in Bangladesh's Khulna-Satkhira region: A focus on fatty acids and amino acids

Lates calcarifer , known as Asian seabass, is a brackish-water teleost species within the order Carangiformes , native to the Indo-Pacific region. In Bangladesh, this species is found in natural habitats and cultivated on a small scale in the southern coastal region, particularly in the Khulna-Satkhira area. This study analyzed the nutritional composition of cultured Asian seabass in two different size categories, 512.06 ± 14.5 g and 1003.5 ± 36.64 g, collected from this region. Our findings revealed significant differences in the proximate compositions of the two size groups, except ash content (independent t-test, p < 0.05). The smaller size group had a notably higher moisture content (74.96 ± 0.04%), whereas the larger fish exhibited significantly greater protein and fat contents (20.48 ± 0.1% and 5.34 ± 0.18%, respectively). Fatty acid analysis showed distinct differences as well; the larger size group contained higher concentrations of saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs), while the smaller fish was richer in polyunsaturated fatty acids (PUFAs). Among the SFAs and omega-3 PUFAs, undecanoic acid and α-linolenic acid were the most prevalent in both groups. However, MUFA profiles differed: palmitoleic acid was dominant in the smaller size group, while oleic acid was more abundant in the larger size group. All essential amino acids (EAAs), except tryptophan, were detected in both groups, with lysine being the most prominent, measuring 5.53±0.44 ^{g/100 g dry weight in smaller size group and 3.91±0.32 g/100 g dry weight in larger size group. Notably, the smaller size group demonstrated a significantly higher overall concentration of EAAs. Overall, this study highlights the nutritional richness of cultured Asian seabass, particularly in terms of fatty acid and amino acid profiles. The superior concentrations of essential amino acids, a higher EPA/DHA ratio, and a more favorable n-3/n-6 ratio in the smaller fish suggest it as a nutritionally superior and well-balanced fish option.}