Effect of dietary taurine and methionine on blood serum lipids, glucose and proteins levels in Persian sturgeon (Acipenser persicus, Borodin, 1897) fed plant-based diets

Application of plant protein resource rather than animal protein in fish diet can help to suppress the feed costs and to eliminate the limitation of animal protein availability. However, the effect of plant protein should be investigated on fish to determine any effect on whole physiology. The effect of dietary taurine and methionine was investigated in Persian sturgeon (Acipenser persicus) fed high plant (soybean meal, wheat gluten) diets. Two separate experiments were conducted. In the experiment 1, the fish were fed diets with constant methionine but 0.05-1.6 % taurine levels. In the experiment 2, the fish were fed with diets containing different methionine (optimal and sub-optimal) and taurine (low and high) levels. After six week feeding, serum glucose, cholesterol, triglyceride, total protein, albumin and globulin levels were determined. The results showed that taurine caused decrease in serum cholesterol and triglyceride levels in the fish. Also, shortage of either taurine or methionine resulted in increase in serum glucose. There was a significant effect of taurine and methionine on serum total protein, albumin and globulin levels (P<0.05). It is concluded that taurine and methionine had interaction effect on serum biochemical characteristics in Persian sturgeon. The possible mechanisms involving in the observed changes were discussed.