Effects of Feeding Diets Containing Different Levels of Shrimp Shell Waste Meal on Growth and Colouration of Koi Carp (<i>Cyprinus rubrofuscus </i>Lacepède, 1803)

Astaxanthin is a xanthophyll carotenoid which is found in various microorganisms and marine animals. The shell of marine shrimp,<i> Aristeus alcocki</i> is a cheap source of astaxanthin. An attempt has been made in the present study to increase the coloration of koi carp (<i>Cyprinus rubrofuscus)</i> by feeding diets with different levels of shrimp shell waste meal (SSWM) prepared from <i>A. alcocki</i>. Four different dietary treatments with varying percentage of SSWM: 0% (F1, control), 5% (F2), 10% (F3) and 20% (F4) were used for the study. The feeding was done for 90 days at the end of which fish were evaluated for growth and colouration. The results indicated that the weight gains in fish fed different levels of SSWM were not significantly different from weight gain in fish fed control diet. The results of the feeding study also demonstrated that feeding diets containing shell waste from <i>Aristeus alcocki</i> enhanced colour of koi carp and increased the carotenoid content in the skin of the fish. It may be concluded that shell waste of <i>A. alcocki </i>could be used as an efficient protein source to replace costly fish meal in the diet of <i>C. rubrofuscus</i>. Moreover, inclusion of shrimp shell waste as a natural carotenoid source in the diet of <i>C. rubrofuscus</i> can ensure appealing skin colour and hence can increase consumer acceptability and market value of the fish.