Seasonal variation in proximate, fatty acid and amino acid profile of freshwater mud eel, Monopterus cuchia (Hamilton, 1822)

Abstract

Throughout the year, fish are subjected to considerable environmental changes and fluctuations in availability and compositions of feed that will affect their proximate, fatty acids and amino acids composition. The purpose of this study was to clarify the seasonal variation in proximate, amino acid and fatty acid profile of freshwater mud eel, Monopterus cuchia. The proximate compositions, total amino acid and fatty acid profile were determined by AOAC, HPLC and GC respectively. Results indicated that proximate (Moisture, Protein and Lipid), amino acid and fatty acid profile varied significantly (p<0.05) among these three seasons (pre-monsoon, monsoon and post-monsoon). However, ash content showed no significant variation among seasons. The amount of protein was higher in monsoon than in pre-monsoon and post-monsoon season. The fat and fatty acid as well as protein and amino acid contents of the investigated fish species showed a significant (p<0.05) seasonal dependency. Among the 14 recorded amino acids (Essential Amino Acid-6, Nonessential Amino Acid-8), the major amino acids in the total crude protein were lysine, glutamic acid, arginine, aspartic acid, leucine and methionine. The ratio of EAA/NEAA was higher in post-monsoon season than pre-monsoon and monsoon season. The findings of the present study also showed that unsaturated fatty acids represented 44.2142%, 57.2339%% and 66.0548% of the total fatty acids, whereas saturated fatty acids accounted for 55.7858%, 42.7661% and 33.9452% in pre-monsoon, monsoon and post-monsoon seasons. The major fatty acids in muscle ofM. cuchia were oleic acid (18:1), palmitic acid (16:0), linoleic acid (18:0),palmitoleic acid (16:1) and lauric acid (C12:0). Fatty acid profile resulted that some fatty acid: tridecanoic acid (C13:0), pentadecenoic acid (C15:1), eicosenoic acid (C20:1), eicosadienoic acid (C20:2), eicosapentaenoic acid (C20:5) and docosapentaenoic acid (C22:5) were not detected in pre-monsoon experimental fish. Most nutritionally important Docosahexaenoic Acid (DHA, C22:6 n-3) was dominant fatty acid in monsoon than post-monsoon. Linoleic acid was the most abundant Poly Unsaturated Fatty Acid (PUFA) in M. cuchia. Fatty acid composition and n-3/n-6 is higher in monsoon than pre-monsoon and post-monsoon season which indicates fishes caught in monsoon season arenutritionally rich, thus advantageous for human health. Therefore, a comprehensive study on Monopterus cuchia (Cuchia) is required for the further confirmation of the result of present study.