Value of Menhaden Oil in Diets of Florida Pompano

Florida pompano (Trachinotus carolinus) juveniles were fed to satiation twice daily on one of four experimental diets containing 12, 8, 4, or 0% menhaden fish oil for 48 days in flowing-water tanks at 28 C (82 F). Basalingredients of the diets were lipid-extracted menhaden fish meal (50%), lipid-extracted, dehulled soybean meal (20%), dextrin (8.9%), cellulose (variable with fish oil) and vitamin and mineral supplements. Fish fed the 8% oil diet gained more weight than those fed the 0 to 12% fish oil diet. Fish fed the diet containing no fish oil gained less weight than those fed any of the diets containing fish oil and had deformed gill opercula and filaments. The gill anomalies are presumed to have been caused by essential lipid deficiencies in the diet. Energy deficiency could also have been responsible for poor growth by the fish fed the diet without fish oil. Energy excess could have caused the fish fed the highest level of fish oil to consume less diet and, therefore, been responsible for their reduced weight gain. Digestibility studies showed that ratio of digestible energy to digestible protein in the most productive diets, 4 and 8% fish oil, was 7.4 to 8.1 kcal/g.