Improvement in spotted rose snapper growth and skin coloration after incorporation of shrimp head meal in diet

Abstract

Four isonitrogenous (45% crude protein) and isoenergetic (20.29 – 20.47 kJ/g) experimental diets were formulated by replacing 0%, 10%, 20% and 30% of fish meal (FM) with shrimp head meal (SHM) as a source of protein and tested the rearing performance and skin coloration of spotted rose snapper Lutjanus guttatus. The SHM had a high content of protein and pigments (i.e., carotenes and xanthophylls), but also chitin which eventually could be an anti-nutritional constituent in the diet for some fish species. A total of 240 fish (initial average weight of 77 ± 0.5 g) were distributed in 12 fiberglass tanks (3000 L) (20 fish/tank) and were fed twice a day for 70 days. The fish feed diets containing SHM showed the highest growth rates (weight gained, WG; 82.8–88.2 g) and lowest feed conversion ratio values (FCR; 1.3 – 1.4) compared to the D-Control diet (WG; 62.1 g and FCR; 1.5). The chitinolytic enzymatic activity (CEA) significantly increased in the stomach of fish fed diets containing SHM. The fish fed diets containing 20% and 30% of SHM, showed higher redness and more reddish-orange tones than the fish fed with the D-Control diet. The FM replacement had improvements in final growth, chitinolytic enzymatic activity, and skin coloration of spotted rose snapper. Thus, the use of up to 30% SHM protein in practical diets for spotted rose snapper should be a good alternative to develop more efficient aquafeed production for these species, however, further research could be suggested to determine the effectiveness of SHM as a substitute for FM in diets for spotted rose snapper rearing at a commercial scale conditions.