Seasonal variations in proximate composition and metallic elements of three cyprinids from a Central Himalayan river Alaknanda in Garhwal Himalaya, India

Fish is an irreplaceable, highly nutritious aquatic food in a balanced diet. On the contrary, fish can also be a source of metal contamination when ingested in excess through food and water. The aim of the present study was to determine the seasonal variations in the proximate body composition and levels of Na, K, Ca, Fe, Zn, Cu, and Pb in the muscle tissue of three fish species namely, Schizothorax plagiostomus, Schizothorax progastus and Barilius bendelisis dwelling in Central Himalayan river Alaknanda at Srinagar (Garhwal)  in Garhwal Himalaya. The protein (21.01-21.74%) and carbohydrates (2.31-2.69%) were found maximum in summer season in all the studied fishes while lipid was found to be highest during monsoon season in S. plagiostomus (2.73%) and S. progastus (2.70%) and lowest (1.62-1.68%) in the winter season. B. bendelisis showed a different pattern of variation in lipid content being highest (6.32%) during summer and lowest (3.34%) in monsoon season. Significantly (F=5.69, p<0.04) high content of lipid was found in B. bendelisis as compared to S. plagiostomus and S. progastus during the three seasons. Na, Ca, K, and Fe were detected highest during monsoon, Pb, and Cu during summer and Zn during the winter season. However, Pb was not detected in all the fish samples during monsoon season. B. bendelisis was significantly (p<0.001)rich in Na and Ca, S. plagiostomus in K (p<0.01), and S. progastus in Fe (p<0.001) content during all three seasons. Ca was rich among macroelements while Fe among microelements in all the studied fishes. The amount of Zn (1.48-4.55 mg/100g), Cu (0.429-0.869 mg/100g), and Pb (0.117-0.447 mg/100g) were within the permissible limits of International food safety guidelines. The seasonal variations in the parameters are attributed to food availability, temperature changes, fish metabolism, and prevailing environmental conditions. Thus, these cyprinid species were regarded as safe and useful for human consumption.