Exploring fatty acid connections between estuarine fish Chelon planiceps and its diatom diet as taste and nutraceutical property influencing factor

Abstract

Chelon planiceps is a widespread commercial fish of Indian Sundarbans with appreciable taste. Taste of fish is primarily influenced by polyunsaturated fatty acids, and since precursors of PUFA in fish cannot be generated de-novo, they are majorly obtained from phytoplankton diet. In the present study, C. planiceps (N = 10) were analysed for fat content in different body parts, and diatoms present in the gut were compared with diatoms found in habitats of the sampled fish. Significant difference in t-test (p ≤ 0.01) was found for lipid content compared between neck, abdomen and tail regions. The gut analysis revealed highest species richness of Coscinodiscus spp. Four species, namely C. radiatus, C. jonesianus, C. oculus-iridis and C. wailesii, were found to be abundant. Other diatoms too were found in the gut (N = 15) and in the habitat (N = 37). Present study focussed on implications of the most abundant Coscinodiscus. The total lipid content and FA profiles revealed 31FAs, with 12SFAs, 11MUFAs and 8 PUFAs together in both the diatom and fish. Coscinodiscus showed a profile of 28FAs of which 19FAs had a minimum representation of >1 % and C. planiceps showed a profile of 9FAs, all showing minimum representation of >1 %. Comparison of the two FA profiles showed Coscinodiscus to be richer in terms of total SFA (47.34 %) and MUFA (33.03 %) whereas, C. planiceps was richer in terms of PUFA (22.17 %). Pearson's correlation coefficient of (−)0.144 indicated a negative correlation between C. planiceps and Coscinodiscus and though this was expected to be a direct impactor the −ve correlation is attributable to the fish's FA metabolism that affects the dietary FA profile that lowers the similarity between the two profiles to a large extent. The nutraceutical significance of the FAs of the fish and its diet highlights the aquaculture implication of the study.