EVALUATION OF DIETARY TAURINE ON BLOOD PARAMETERS, SOMATIC INDICES AND LIVER STATUS OF Totoaba macdonaldi  

Taurine has been reported as an indispensable nutrient for larvae and juvenile of various marine species, which can be vital in metabolic pathways needed for maintenance and growth. Totoaba, an endemic species from Gulf of California, is an important candidate for commercial aquaculture in Mexico. Therefore, a 10 weeks of feeding trial was conducted to evaluate the effect of dietary taurine on blood parameters, somatic indices and liver status of juvenile totoaba. Eight isoproteic (50%) and isolipidic (12%) experimental diets were formulated to contain graded levels of taurine (0.05% (control diet), 0.3%, 0.6%, 0.9%, 1.2%, 1.5%, 1.8%, 2.1%). Triplicate groups of 20 fish (10 g) were randomly stocked in 100L tanks in a recirculating system and fed to satiation twice daily.

No significant differences (P>0.05) were observed for survival, growth performance and feed intake, however fish fed taurine 0.3% showed highest weight gain. Dietary taurine affected blood lipid metabolism (cholesterol and triglycerides), bilirubin, hepatosomatic index, viscerosomatic index and gallbladdersomatic index of totoaba. The lowest gallbladdersomatic index, plasma cholesterol and triglycerides were observed in fish fed unsuplemented taurine diet (0.05%). Also, green liver was observed in this control diet, indicating abnormal physiological condition due to dietary taurine deficiency. There were no differences (P>0.05) in hematocrit, liver lipid and glycogen between all diets. Results indicated that dietary taurine supplementation affected lipid metabolism in juvenile totoaba. Digestibility, lipase activity and metabolic enzymes will be determined and discussed.