Effect of dietary citric acid supplementation and partial replacement of dietary fish meal with soybean meal on calcium and phosphorus of muscle, scute and serum of Beluga, <i>Huso huso</i>

Abstract

Beluga is one of the most important fishes in Caspian Sea. The purpose of this experiment were to evaluate the effect of soybean meal (SBM) as a fishmeal (FM) partial replacement and citric acid (CA) supplement on the calcium (Ca) and phosphorus (P) of muscle, scute and serum of Beluga diets. Three isonitrogenous and isoenergetic experimental diets were formulated, they are SBM₁ (soybean protein (SBP): fish protein (FP) = 1:3), SBM₂ (SBP : FP = 2:3) and SBM₃ (SBP : FP = 1:1). Diets were supplemented with CA at 0 and 3%. The fishes (average weigh 25.1±1.9 g) were fed at 3 to 4% of body weight for four times a day over 8 weeks. At the end of the feeding trial, Ca and P of muscle, scute and serum were determined. Ca and P of muscle and serum were significantly higher in 3% CA. P of scute was also significantly higher in 3% CA; however, dietary CA had no effect on Ca of scute. Although the results of this study showed that partial replacement of fish meal with soybean had no effects on the calcium and phosphorus of muscle, scute and serum in beluga.

Key word: Citric acid, soybean meal, calcium, phosphorus, Huso huso