Precocious development of the digestive system in relation to early appearance of piscivory in striped bonito Sarda orientalis larvae |
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| Authors: | TATSUYA KAJI MASAAKI KODAMA HIROSHI ARAI MASATOMO TAGAWA AND MASARU TANAKA |
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| Institution: | Laboratory of Marine Stock-Enhancement Biology, Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, Kyoto 606-8502 and; Tokyo Sea Life Park, Edogawa, Tokyo 134-8587, Japan |
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| Abstract: | ABSTRACT: Striped bonito Sarda orientalis larvae and juveniles were reared in a laboratory from hatching to 14 days post hatching, and the development of their digestive system was investigated histologically. On day 2 (first feeding day), the larval-type digestive system was differentiated. On day 3, a blind sac with densely distributed gastric glands developed and pyloric ceca appeared, suggesting that the digestive system was attaining adult-type structure. The yolk was completely absorbed on day 4. Bonito larvae preyed on rotifers and/or Artemia nauplii on day 2, but almost the whole gut was occupied by fish larvae from day 4. In the striped bonito, the adult-type digestive system was established right after first feeding, and this precocious development was well synchronized with the appearance of piscivory. |
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| Keywords: | development digestive system gastric gland larva piscivory scombrids striped bonito |
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