報告書番号

U00021

タイトル（和文）

イソゴカイによるヒラメ糞処理速度の解明

タイトル（英文）

Biodegradation of the feces of Japanese flounder by a polychaete, Perineris nuntia vallata.

概要 （図表や脚注は「報告書全文」に掲載しております）

水産生物を用いた養殖残渣処理技術を開発するため、干出状態においたイソゴカイにヒラメ糞を与え、イソゴカイのヒラメ糞摂餌速度などについて検討した。6時間の干出の間にイソゴカイは、ヒラメ糞を1.8～2.2mg/個体/h(20～25℃、乾燥重量)で摂餌して増重し、ヒラメ糞はイソゴカイの飼料となることが明らかになった。6時間の間にヒラメ糞を摂餌したイソゴカイの糞排泄量は2.7mg/個体/日であり、摂餌量に対する糞排泄重量は平均22.4%であった。また、イソゴカイのアンモニア排泄量は0.06mg-N/個体/日であった。以上の結果より、ヒラメ糞を摂餌したイソゴカイは、摂取窒素の約19%を糞、約14%をアンモニアとして排泄し、摂取窒素の約66%がイソゴカイの成長に用いられると推定した。

概要 （英文）

Biodegradation of the feces of Japanese flounder fed on commercial pellets by a polychaete, Perineris nuntia vallata, was evaluated. The feed intake rate of the polychaete fed on the feces of Japanese flounder under the low tide level of minus 0.5 cm for 6 h were 0.6 to 0.7 mg/individual/h(dry weight) at 15℃, 1.8 to 1.9 mg/individual/h at 20℃ and 1.8 to 2.2 mg/individual/6h at 25℃. The polychaete were reared with commercial pellets for Japanese flounder, commercial diet for polychaete and feces of Japanese flounder. Although the weight increment rates and feed conversion efficiencies were 2 to 3 times higher in the polychaete fed on commercial pellets and diet than the polychaete fed on the feces of the flounder, the protein efficiency ratio showed same value between three groups. It was estimated that the feces of Japanese flounder has about 50% dietary value of commercial pellet and diet for the polychaete. Daily feces excretion of the polychaete was 2.7mg/individual/day, and it was 22.4% of weight of Japanese flounder feces ingested. Ammonia excretion was 0.06mg/individual/day. Individual polychaete ingested feces of the flounder as feed-N at the rate of 0.4 mg-N during 6h low tide, excreted the feces-N of the polychaete at the rate of 0.08 mg-N/day. It also excreted ammonia-N at the rate of 0.06mg/day. Therefore about 66% of nitrogen in the feces of Japanese flounder was reduced through this process.

報告者

キーワード