Production performance of Pacific bluefin tuna Thunnus orientalis larvae and juveniles fed commercial diets and effects of switching diets
2016
Cho, J. (Tokyo University of Marine Science and Technology, Minato, Tokyo (Japan). Graduate School of Marine Science and Technology) | Haga, Y. | Kamimura, Y. | Akazawa, A. | Itoh, A. | Satoh, S.
Survival rate of PBT from hatch to juvenile is less than 2%. One reason of lower survival could be due to limited supply of prey fish such as Spangled emperor Lethrinus nebulosus and Japanese parrotfish Oplegnathus fasciatus. In order to solve this problem, this study aimed to determine suitable formulated commercial diet to replace prey fish. We evaluated the dietary utility of CM1, CM2 and CM3, commercially available, and control prey Spangled emperor fish larvae to Pacific bluefin tuna larvae and juveniles. PBT larvae at 21 days post-hatch with mean total length of 20.2 mm were fed prey fish larvae and the CM1 diet during the first four days of the feeding trial and weaned onto each diet to examine the effect of switching diets on feed acceptance. Survival and growth were compared after day 11 of the feeding trial. Among the test diet groups, the highest survival occurred for CM1, followed by CM2 and CM3. Of the groups, the CM3 group had significantly greater total length and body weight. These results suggest that PBT larvae and juveniles can readily acclimate to formulated commercial diets once they are successfully weaned onto a suitable formulated diet such as CM1.
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