Effects of spirulina carotenoid on carotenoid deposition and immunity in sex-reversed red tilapia

A study was conducted in 235-l glass tanks filled with 180-l water using closed recirculation water system of 1.2 l/min flow rate to determine the effects of spirulina carotenoid on its accumulation and immune in sex-reversed red tilapia. Feeding trial comprised 8 treatments with 3 replications each. Twenty fish of 21 g initial weight were stocked in each tanks into which feed were given in 2 rations daily over an 8 weeks period of study with completely randomized design. All feeds tested contained 30% protein, 6% lipid and 3,400 Kcal digestible energy/kg feed. Formula 1 feed was control, i.e., without fortified carotenoid; formulae 2, 3 and 4 were with 200 mg/kg feed of fortified synthetic carotenoids, i.e., astaxanthin, zeaxanthin and bata-carotene, respectively. Dried spirulina were incorporated in feed formulae 5 to 8 to obtain carotenoid concentration 50, 100, 150 and 200 mg/kg feed, respectively. Results showed that neither synthetic nor spirulina carotenoid produced an effect on fish growth or survival. Analysis of total carotenoid showed both sources of carotenoid elevated carotenoid content and color index in proportional to carotenoid level fortification. Highest accumulated carotenoid content was noted in feed with zeaxanthin in the feed though not different from that with 150 mg/kg spirulina carotenoid. Antibody against Streptococcus agalactiae was enhanced with carotenoid fortification in all formulae except that with beta-carotene. Carotenoid in the feed has no effect on total hemoglobin and hematocrit, though it increases red blood cell and white blood cell (p