Dietary Supplementation with Shrimp Processing Waste Extracts in Astaxanthin-Containing Diets Improves Pigmentation of Blood Parrot Cichlids (Vieja melanurus × Amphilophus citrinellus)

Red coloring determines the commercial value of blood parrot cichlids (Vieja melanurus × Amphilophus citrinellus). While synthetic astaxanthin (SA) is commonly used to improve hue, its expensive cost has prompted the quest for more sustainable alternatives. This 60-day study looked at shrimp waste extract (SWE) as a dietary supplement for color improvement. Fish were assigned to five diets: basal control (G1, 0 mg/kg SA: 0 mg/kg SWE), SWE alone (G2, 0 mg/kg SA: 7.7 mg/kg SWE), high SA (G3, 90 mg/kg SA: 0 mg/kg SWE), moderate SA (G4, 45 mg/kg SA: 0 mg/kg SWE), and mixed SA with SWE (G5, 45 mg/kg SA: 7.7 mg/kg SWE). Growth and CIELAB skin pigmentation were evaluated. Growth performance was consistent across all treatments. Colorimetric study found that while the SWE alone (G2) significantly improved pigmentation compared to the control, it was less effective than the high-SA diet. However, incorporating SWE into the moderate-SA diet (G5) resulted in a promising complementary response. Despite having half the SA concentration, G5 achieved pigmentation that was comparable or superior to the G3 diet by the end of the feeding trial. These data revealed that, while SWE has lower independent activity, it is an effective complementary additive for shortening the feeding period required to achieve a similar redness. Finally, SWE enables the partial substitution of synthetic astaxanthin, providing a cost-effective and environmentally sustainable nutritional strategy for the ornamental aquaculture business.