Enhanced Body Pigmentation in Leopard Coral Grouper (Plectropomus leopardus) in Response to Environmental Background and Feed Additives

Abstract Groupers are among the most popular fish commodities worldwide owing to their palatability and appearance. However, their body pigmentation considerably affects their consumer acceptability and pricing, making their culture challenging. The present study aimed to improve the body pigmentation of the leopard coral grouper ( Plectropomus leopardus ) by investigating the effects of tank color, shading, and feed additives over 28 days. The fish were reared in tanks of different colors (white, black, red, and green), and their net cages were shaded at 0%, 50%, and 80%. The fish reared in the black and green tanks or under 80% shading exhibited the most vibrant skin coloration. Skin color enhancement was tested in feeding trials, during which the fish were fed different concentrations of additives: astaxanthin (0 (control), 1000, 2000, and 3000 mg), vitamin E (1000, 2000, and 3000 mg), and plant extracts (250, 500, and 750 mg) kg -1 of diet. Fish fed the 3,000 mg of astaxanthin kg -1 diet displayed the best pigment enhancement, whereas those fed with vitamin E and plant extracts showed reduced pigmentation. Feeding with different ratios (0%, 10%, 20%, and 30%) of krill meal in the diet showed that body pigmentation was best enhanced by 20–30% krill meal. In conclusion, our results imply that black- and green-colored rearing tanks under 80% shading and a diet with 20–30% krill meal and 3,000 mg astaxanthin kg -1 constitute ideal conditions to enhance the body pigmentation of P. leopardus .