Ảnh hưởng của hàm lượng chất màu chiết xuất từ củ dền (Beta vulgaris) bổ sung vào thức ăn lên sinh trưởng và màu sắc của cá khoang cổ nemo (Amphiprion ocellaris Cuvier, 1830)

Abstract

     One-factor experiment was designed in a completely randomized design for a period of 75 days to evaluate the effect of colorant concentration, extracted from red beetroot, supplemented to the feed on the results of clownfish culture. Fingerlings at initial size of 0.81 ± 0.07 g and 3.47 ± 0.05 cm were placed in a recirculating aquaculture system (65 liters/tank) at a density of 15 fish/tank. The growth parameters, survival rate, feed efficiency and color of the fish were evaluated at the end of the experiment. Results showed that the supplementation of colorants extracted from red beetroot to the feed improved the growth parameters of fish. The final length and body weight of fish in the treatment supplemented with 350 mg/kg (4.13 ± 0.02 cm; 1.37 ± 0.02 g) were higher than that of the control (4.04 ± 0.02 cm; 1.28 ± 0.01; P < 0.05). Feed efficiency at the levels of 150 – 450 mg/kg was higher than that of the control (62.6 – 65.1% compared to 55.9%; P < 0.05). The supplement concentration of 350 - 450 mg/kg feed also significantly improved fish skin color (a* index, 9.50 - 10.48) and accumulated carotenoids content (28.14 - 30.60 μg/g skin) compared with other treatments (P < 0.05). However, the supplementation of colorants from red beetroot to the feed did not affect the condition factor (K) and survival rate (SR) of the fish (P > 0.05). This study shows the potential of using natural source of colorants from red beetroot in improving the performance of marine aquarium fish; and the content of 350 mg/kg of feed is recommended to be suitable for false clown anemonefish.