ANALYSIS OF CAROTENOIDS IN THE PIGMENTATION OF THE SNAPPER SPOTTED ROSE Lutjanus guttatus (STEINDACHNER, 1869) GROWN IN CIRCULAR FLOATING CAGES

The spotted rose snapper Lutjanus guttatus , is the second most important snapper of a commercial in the Mexican Pacific Ocean. Natural stocks have pigmentation problems when they are taken to captivity, which are transferred to larvae that lose commercial value due to the low skin color. The bioassays were designed to provide the following diets: 1. Commercial diet + shrimp head (triplicate), 2.- Commercial diet (triplicate) and 3.- Fish fed with natural foods. Temperature, salinity, pH, dissolved oxygen, nitrites, nitrates, ammonium and phosphate were monitored. Biometric analyzes were performed every 10 days to calculate the supply of food rations. In 180 days of cultivation the daily growth (2.02 gr) and  survival (73%). The shrimp feed/head trea tment was the one that showed a better performance in the culture as well as in the pigmentation of the skin with carotenoids, at the beginning of the culture (2.44 ± 1.01) and, at the end of the culture (17 , 31 ± 6.57) vs without a shrimp head starting the culture (3.60 ± 1.53) and at the end the culture (7.49 ± 3.26). The results indicate that adding by-products such as shrimp head to red-skinned fish such as snapper  L. guttatus increases skin pigmentation.