LARGEMOUTH BASS MICROPTERUS SALMOIDES
F. Kubitza, L.L. Lovshin, R.T. Lovell-1997
Aquaculture, 148: 191-200
Abstract:
Three trials were performed to identify feed enhancers for largemouth bass. Fish trained on dry pellets were stocked into 45 1 aquaria. Trial I evaluated the palatability of diets in which fish meal (FM) was replaced with 0, 20, 40, and 60% soybean meal (SM-OO, SM-20, SM-40 and SM-60). Feed intake declined as dietary concentration of soybean meal increased (P < 0.01). SM-60 was used as the control and basal diet in trials 2 and 3. Trial 2 tested the following mixture of substances: (1) amino acids: alanine, glycine, proline, serine, leucine, valine, histidine, and tryptophan; (2) nucleotides: inosine and inosine-5-monophosphate (IMP-5'); (3) betaine. Dietary concentrations of chemicals were kept in the same molar ratio as in aqueous krill (Euphasia pacifica) extract. Chemical groups were tested alone or in all possible combinations. Nucleotides alone enhanced feed intake of fish by 46% compared with the control diet (P < 0.05), while amino acids and betaine were ineffective ( P > 0.05). No additive effects among chemical groups were observed (P > 0.05). In trial 3, inosine and IMP-5' were tested alone at 1400, 2800, and 5600 mg/kg of feed or together, each at 2800 mg/kg of feed. A diet with 10% fish meal (FM-IO) was also evaluated. Effective dietary concentration of IMP-5' seems to be about 2800 mg/kg of feed which gave a feed intake 23% higher than the control diet (P<0.05). Dietary IMP-5' level of 5600 mg/kg of feed failed to further increase feed intake (P > 0.05). Inosine was not an effective feed enhancer at the dietary levels tested (P > 0.10). No significant additive effect of inosine in a diet flavored with IMP-5' at 2800 mg/kg of feed was found (P > 0.10). Feed intake was highest for fish fed FM-IO (P < 0.01), about 58% superior than feed intake for the control diet. This study showed that IMP-5' and fish meal were effective feed enhancers, while increasing dietary concentration of soybean meal depressed feed intake of largemouth bass.
(ESALQ-USP/DZ. Av. Pádua Dias. 11, Piracicaba, SP. 13418-900, Brazil)
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