Abstract:
This study examined the influence of Astaxanthin added in feed on pigment accumulation in the muscle-skin, as well as resistance to salinity stress and copper toxicity of clownfish (Amphiprion ocellaris). Mean length of fish was 33.05 ± 3.29 mm. Five experiments were performed with synthetic Astaxanthin contents: 0, 50, 100, 150 and 200 mg/kg diets. After 8 weeks of the experiment, the pigment accumulation of Astaxanthin in the muscle-skin of clownfish was the lowest in the control treatment of 2.11 ± 0.13 µg/g, while these treatments of 150 and 200 mg/kg diets were over 10 µg/g. The treatments of 150 and 200 mg Astaxanthin/kg increased the resistance to copper toxicity and salinity stress test of the fish. The resistance of the fish was longer (>50 minutes) compared to the control (42.4 minutes) in an environment with salinity of 0‰ (p<0.05); The mortality was below 68% instead of 100% in the control after 5 and 7 days of culture in the environment 5‰ and 10‰, respectively (p<0.05). The survival rate of fish was over 75%, respectively, significantly higher than the control (54%) when being cultured in the environment of Cu2+ - 96 h (p<0.05). However, there were no significant differences in accumulation of Astaxanthin and resistance to the stress test in two treatments of 150, 200 mg/kg diets (p>0.05). Thus, the optimal content of astaxanthin supplement in fish food was 150 mg/kg diet, which created high pigment accumulation in the muscle-skin; increased resistance to salinity stress and copper toxicity.