Optimizing the Supplementation of Calcium and Phosphorus in the Diets of Asian Seabass (Lates calcarifer) in Freshwater based Recirculating Aquaculture System

Background: Calcium and phosphorus are important mineral nutrients for all energy-producing cellular and metabolic pathways. Fish obtain Ca and P from their feed because of the low level of calcium and phosphorus in the freshwater especially in the RAS system. This study was investigated to evaluate the growth characteristics, survival rate, calcium and phosphorus composition and haematological and biochemical parameters of Asian Seabass (Lates calcarifer) under the influence of varied combinations of calcium and phosphorus in the formulated sinking feed. Methods: The experiment was carried out with Asian Seabass fingerlings, each with an initial average weight of 2.00±0.15 g which were randomly distributed in 54 Nos. of PE tanks with a volume of 500 Litres @ 30 Nos./tank. The experiment duration was 60 days and was carried out in a 6×3 factorial design. The fishes were fed with a sinking pellet diet containing calcium Ca 0.0, Ca 0.5% and Ca 1.0% and phosphorus P 0.0, P 0.5%, P 1.0%, P 1.5%, P 2.0% and P 2.5% and all the possible combinations of above percentages of calcium and phosphorus in the experimental diets. Result: The growth characteristics and survival rates were significantly higher in 1% of calcium and phosphorus-contained feed, the calcium and phosphorus composition and haematological and biochemical parameters also confirmed the experimental results. Our study outcome was useful for formulating a calcium and phosphorus-incorporated sinking feed to Asian Seabass for better growth in the recirculating aquaculture system.