49B-21 |
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A. Bezerra and A. M. MARTIN. Dept. of Biochemistry, Memorial Univ. of Newfoundland, 300 Prince Philip Dr., Saint John's, NF A1B 3X9, Canada There is interest in some areas of Latin America in the expansion of aquaculture operations, and the development of a low–priced, locally produced protein source for the feeds for the cultivated fish is needed. The objective of this work was to study the utilization of diets based on acid hydrolysates of fish wastes fed to cultivated tambaqui fish (Colossoma macropomun). Discards from fisheries operations were mixed with 3% (w/w) formic acid (85%), and 1% of potassium sorbate to prevent mould growth. The resulting liquid hydrolysates were incorporated into the diet of cultivated tambaqui. The experiments used fifteen tanks with 15 fish each, fed twice a day for 90 days. The fish were weighed regularly to calculate their growth parameters. A paired sample test was used to compare the means of initial and final weight for the fish fed with the diet prepared with the hydrolysate, to those of the control experiments using fish meal. The growth response of cultivated tambaqui fed with acid fish hydrolysate was good, and no mortality occurred during the growth trial. The paired sample correlation coefficient showed that all fish grew proportionally to their original weight, and the variations in the weight gain for fish grown under different diets were small. The specific growth rate (SGR) was 1.37 ± 0.31 %/day, very close to the value of 1.50 ± 0.39 %/day found for the control diet. A feed conversion ratio (FCR) value of 2.13 ± 0.88 was obtained with the hydrolysate feeding trial, which was higher than the corresponding value of 1.98 ± 0.28 for the fish meal. The excellent feed utilization and growth response achieved with the acid hydrolysate-based diet that was tested confirm that formic acid fish hydrolysates can be used as an alternative protein source in aquaculture feed production.
Session 49B, Aquatic Food Products: General
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