報告書番号

U90016

タイトル（和文）

高能率魚類生産のための水質浄化技術の開発４．ヒラメの窒素排泄量について

タイトル（英文）

DEVELOPMENT OF WATER-PURIFICATION TECHNOLOGIES FOR INTENSIVE FISH CUFTURE ESTIMATION OF NITROGES EXCRETION OF JAPANESE FLOUNGER PARALICHTHYS OLIVSCEUS

概要 （図表や脚注は「報告書全文」に掲載しております）

循環濾過養魚システムにおける，濾過槽への汚濁負荷量（魚の排泄物量）を明らかにすることを目的として，ヒラメの窒素排泄量について測定した。１．安静時；（１）アンモニア，尿素排泄量は，それぞれ含窒素性排泄物全体の７０～７５％，１５～２０％を占めた。（２）単位体重あたりのアンモニア，尿素排泄量は体重の増加に伴って低下した。（３）ヒラメの尿量は約２ｍ■／１００ｇ／日であった。また，窒素排泄物全体に占める尿の割合は小さいものと推定された。２．摂餌時；（１）単位時間あたりのアンモニア排泄量は，摂餌直後から安静時の２／５倍程度に上昇し，その値は摂餌率の高いものほど長く続いた。（２）単位時間あたりの尿素排泄量は，摂餌後６～２４時間でピークを示した。（３）１日あたりのアンモニア，尿素および糞の排泄量は摂餌率の上昇に伴って増えた。また，最も多く排泄された窒素はアンモニア態であった。（４）本試験では，摂取した窒

概要 （英文）

IN THIS STUDY,NITROGENOUS EXCRETION,ESPECIALLY AMMONIA-N AND UREA-N,WAS DETERMINED FOR FED AND STARVED JAPANESE FLOUNDER,PARALICHTHYS OLIVACEUS,OF 2 TO 575 G BODY WEIGHT. THE CHARACTERISTICS OF THE URINE AND FECES WERE ALSO ANALYZED. ALL THE EXPERIMENTS WERE CARRIED OUT AT 20DEGREE. THE RESULTS ARE AS FOLLOWS: 1. STARVED EXPERIMENT;(1)THE AMOUNTS OF AMMONIA-N AND UREA-N EXCRETED ACCOUNTED FOR 70%TO 75% AND 15% TO 20% OF THE TOTAL-N EXCRETION,RESPECTIVELY.(2)THE AVERAGE AMMONIA-N EXCRETION RATES OF 2 TO 5 G (JUVENILE),15 TO 49 G (YOUNG),AND 163 TO 575 G (IMMATURE) FLOUNDERS WERE 18.3,5.4,AND 4.8 MG-N/100 G-FISH/DAY,RESPECTIVELY. AVERAGE UREA-N EXCRETION RATES AT THE SAME WEIGHTS WERE 2.1,1.7 AND 1.0 MG-N/100 G-FISH/DAY,RESPECTIVELY.(3)THE AVERAGE URINE AMOUNT FOR 360 TO 751 G BODY WEIGHT WAS 2 M LITRE/100 G-FISH/DDAY TENT OF THE URINE WAS 0.5 MG-N/MLITRE. 2. FED EXPERIMENT;(1)BOTH THE AMMONIA-N AND UREA-N EXCRETION RATES PERUNIT WEIGHT PER DAY INCREASEDWITH INCREASING FEEDING RATES.(2)AFTER FEEDING,THE AMMONIA-N EXCRETIONRATE PER UNIT WEIGHT PER HOUR INCREASED IMMEDIATELY AND WAS 2 TO 5 TIMES HIGHER THAN THAT OF STARVED FISH. HIGH EXCRETION RATES CONTINUED FOR12 TO 24 H FOR JUVENILE AND YOUNG FLOUNDERS,AND 12 TO 48 H FOR IMMATURE FLOUNDERS. THE UREA-N EXCRETION RATE PER UNIT WEIGHT PER HOUR PEAKED AT 6 TO 24 H AFTER FEEDING. THE FECES-N EXCRETION RATE PER UNIT WEIGHT PER DAY INCREASED WITH INCREASING FEEDING RATE. FECES-N EXCRETION ACCOUNTED FOR ABOUT 50% OF THE AMMONIA-N EXCRETION FOR JUVENILE AND YOUNG FLOUNDERS,AND 20% TO 25% FOR IMMATURE FLOUNDERS. 3. NITROGEN BUDGET; 40% TO 50% OF THE CONSUMED NITROGEN WAS EXCRETED BY JUVENILE FLOUNDERS AT AFEEDING RATE OF 3% BODY WEIGHT PER DAY,BY YOUNG FLOUNDERS AT A FEEDINGRATE OF 1.2%,AND ALSO BY IMMATURE FLOUNDERS AT A FEEDING RATE OF 0.5%.

報告者

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