| Abstract: | Culture of hybrid striped bass has been expanding in the United States and further growth has been predicted, however, several problem areas exist, including a lack of nutritional information. This series of studies offered reciprocal cross juvenile hybrids several of the commercially available feeds and several different types of purified experimental diets. Weight gain and feed efficiency of fish fed the commercially available feeds formulated to meet the general requirements of salmonids were better than fish fed feeds formulated to meet the nutritional requirements of catfish. Experimental diets containing casein as the primary protein source were unpalatable regardless of the level of fish oil added (6 or 12%) but were accepted if 10% menhaden fish meal was added. Addition of lower levels of fish meal resulted in decreasing degrees of acceptance. Thus, the minimum level of fish meal that elicited a feeding response appeared to be between 510% of the dry diet. A crystalline amino acid test diet was palatable, and weight gain of fish fed that diet was 65–91% of the weight gain recorded for fish fed the positive control diets. Addition of L-arginine, L-methionine or L-cystine to a purified diet containing casein did not result in dietary acceptance. Whole-body proximate composition offish revealed a general trend toward increased lipid levels with increasing levels of dietary lipid. All fish exhibited microvessicular hepatopathy, regardless of diet fed. Hepatocytes contained both glycogen and lipid in the cytoplasm. |
