EFFECTS OF DIETARY CATFISH AND MENHADEN OILS ON HYBRID STRIPED BASS PRODUCTION

Hybrids of female striped bass Morone saxatilis and male white bass M. chrysops were stocked at 14,000 fish/ha in earthen ponds and fed an e xperimental diet supplementally sprayed (2.5% by weight) with either c atfish oil (GO) or menhaden oil (MO). The sprayed diet contained n-3 h ighly unsaturated fatty acids (HUFA, with four or more double bonds) a t 1.10% and 1.54% of diet for CO and MO, respectively. Fish were fed t o apparent satiation twice daily for 212 d in three replicate 0.05-ha ponds per diet. There were no significant differences (P less than or equal to 0.05) between CO and MO diets in mean total weight of fish at harvest (590 and 585 g, respectively), percent weight gain (584% and 576%), survival (87% and 91%), or feed conversion (weight of feed as f ed/fish weight gain; 2.50 and 2.31). Mean intraperitoneal fat (IPF) to body weight ratios of fish were not different (4.8% for CO and 4.4% f or MO). Females had a significantly higher IPF ratio (5.2%) than males (4.7%) across both diets. There were no significant differences in pr oximate composition of whole body or fillet tissue nor in total lipid or glycogen in liver between fish fed either diet. There also were no significant differences in the fatty acid composition of liver tissue. However, the IPF of fish fed the MO-supplemented diet had significant ly higher levels of total polyunsaturated fatty acids and n-3 HUFA. To tal monoenes in IPF were significantly higher for fish fed the diet sp rayed with CO. Based on these results, supplementation of practical di ets with either CO or MO resulted in acceptable performance of hybrid striped bass, but the fatty acid composition of the IPF differed betwe en the two diets.