SALTED SARDINE RESIDUE TO FEED COBIA: ZOOTECHNIC ADVANTAGES AND HISTOLOGICAL RESPONSES

Abstract

Industrial fish processing generates a significant amount of wastes, which are high-value nutritional by product. Therefore, the use of fish residues could be a sustainable practice for fattening marine finfishes. In the present study, we have evaluated the benefits of feeding cobia juveniles with three different diets based on residues of salted sardine: (i) formulated with acid silage of salted sardine residue; (ii) formulated with salted residue combined with an acidity regulator; and (iii) pure salted sardine residue. Fishes that were feed with pure salted sardine residue had significant body weight gain and also expressed a lower feed conversion rate. Fishes feed with the other two diets presented a similarly lower zootechnic performance. Also, no significant changes indicating a harmful effect of salted sardine residue for cobia feed were observed in the digestive tract of any the fishes. However, the diet based only on salted sardine residue showed higher organosomatic indexes. That can be attributed to the rich lipid and fatty acid contents of pure residue and it can be an indicative that silage processing was unable to provide the same amount of fatty acids, as pure residue diet did. In conclusion, our results indicate that pure salted sardine residue was the best choice of feed for the cobia. The use of salted sardine residue as diet complementation should be further evaluated, since its use can improve aquaculture development as an instrument of fishery resources conservation.