INFLUENCE OF NATURAL AND ARTIFICIAL COLOUR ENHANCERS IN THE COLOUR ENHANCEMENT OF ADULT GOLDFISH CARASSIUSAURATUS (LINNAEUS, 1758)

摘要

Color plays a major role in the overall preference and acceptability of ornamental fishes. In the present study the feeding trials were conducted in adult goldfish to assess the effect of two natural (spirulina and shrimp head meal) and two artificialcolour enhancers ((3-carotene and astaxanthin) on the growth and colour enhancement. The experiment was carried out for a period of 60 days. The fish were fed with experimental feed twice a day at the rate of 5 percent of their body weight. A threefoldincrease in growth was observed in the fishes fed with 4% spirulina incorporated feed when compared to control. There is an increase in mean weight gain corresponding to the increase in the shrimp head meal inclusion level. The maximum mean weight gain was recorded in the fishes fed with 0.03 % level of P-carotene compared to the control. The astaxanthin fed fishes gained threefold increase in the mean weight gain at 0.004% level. The highest carotenoid content was observed in the P-carotene fed fishesat 0.02% level when compared to other diet and control. This study confirmed that, the artificial source of carotenoid is better for the colour enhancement, of adult goldfish rather than natural source.