Fish waste silage as a functional ingredient for Octopus maya nutrition

Abstract The nutritional composition of fish silage (FS) from Ocyurus chrysurus and blue crab silage (CS) from Callinectes sapidus was evaluated to determine their application in diets for Octopus maya juveniles. The proximal composition, amino acid, and fatty acid profile of silages were evaluated. The experimental diets were fish silage (FSD), crab silage (CSD) containing 15% of FS and CS, respectively, and fish-crab silage (FCSD) containing 7.5% of FS and 7.5% of CS. The WSD (control) contained only crab and squid meal. O. maya juveniles (body weight 0.33 ± 0.02 g) were fed these diets for 37 days. After this period, survival, growth performance, digestive enzymes, glycogen of the digestive gland (DG), and muscle in O. maya were analyzed. Crude protein was the predominant nutrient in both silages: 50.7% for FS and 37.9% for CS (dry matter basis). Among the 16 amino acids identified, glutamate and glycine predominated in both silages. The CS had low lipid content (6.6%) compared to FS (16.6%), and palmitic, oleic, tridecanoic, and stearic acids were the most abundant fatty acids in both silages. No significant differences were found in growth performance and hepatosomatic index. However, the FSD promoted higher survival (90%) compared to the other diets (82 at 84%). The results of glucose, triglycerides, cholesterol, glycogen, and specific activity (acid and alkaline) of the DG indicate that FSD promotes equivalent results as the WSD. In conclusion, FS is a valuable ingredient in the preparation of octopus feed.