EFFECTS OF DIFFERENT TAURINE LEVELS ON GROWTH PERFORMANCE AND FEED UTILIZATION OF JUVENILE Totoaba macdonaldi

Totoaba is a carnivorous marine species with great potential for commercial aquaculture in Mexico. The use of plant protein in aquaculture feeds, especially for carnivorous fish, is limited by its lack of taurine. It is an essential nutrient for various marine species, which can be vital in metabolic pathways needed for maintenance and growth. The objective of this study was to investigate the effect of dietary taurine supplementation on growth performance and biological parameters of 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%). Totoaba juveniles (10 g) were stocked in 100L tanks (20 fish/tank) supported by a recirculating system with three replicates per treatment. The fish were fed twice daily to apparent satiation.

After 10 weeks of feeding trial, no significant differences (P>0.05) were found in weight gain, feed intake and feed conversion rate among totoaba fed the different taurine diet. However for biological indices, significant effects were attributed to taurine supplementation, with fish fed unsupplemented taurine diet (0.05%) having lower Gallbladdersomatic index than fish fed the remaining dietary treatments (P<0.001). Green liver was observed in this control treatment possibly related to taurine deficiency. These results indicate that juvenile totoaba require taurine around 0.3% in diets containing fish meal as the only protein source.