Diel and ontogenetic body density change in Pacific bluefin tuna, Thunnus orientalis (Temminck and Schlegel), larvae     

Toshinori Takashi  Hirotoshi Kohno  Wataru Sakamoto  Shigeru Miyashita  Osamu Murata  & Yoshifumi Sawada 《Aquaculture Research》2006,37(12):1172-1179

Diel and ontogenetic changes in larval body density related to swim bladder volume were investigated in Pacific bluefin tuna, Thunnus orientalis, to determine the causality of larval mortality – adhesion to the water surface and contact with the tank bottom during seedling production. The density of larvae with deflated swim bladders increased with total length and days post hatch. Diel density change was observed after day 2 post hatch; owing to daytime deflation and night‐time inflation of the swim bladder, the density was relatively higher during the daytime. Increased swim bladder volumes clearly reduced larval density during the night‐time after day 9 post hatch. However, the density of larvae with inflated swim bladders was greater than rearing water density (Δρ>0.0099). The small density difference between larvae and rearing water (Δρ=0.0022?0.0100) until day 4 post hatch may have caused larval mortality by adhesion to the water surface because larvae can be easily transported to the water surface by aeration‐driven upwelling in rearing tanks. Density increased noticeably from day 5 to day 9 post hatch. The increased density difference (Δρ=0.0065?0.0209) in larvae and rearing water possibly induced mortality by contact with the tank bottom because larvae sink particularly during the night‐time on ceasing swimming.  相似文献   

The Presence of Disease-Associated Prion Protein in Skeletal Muscle of Cattle Infected with Classical Bovine Spongiform Encephalopathy     

Hiroyuki OKADA  Kohtaro MIYAZAWA  Shigeo FUKUDA  Yoshifumi IWAMARU  Morikazu IMAMURA  Kentaro MASUJIN  Yuichi MATSUURA  Takashi FUJII  Kei FUJII  Soichi KAGEYAMA  Miyako YOSHIOKA  Yuichi MURAYAMA  Takashi YOKOYAMA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2014,76(1):103-107

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Heterogeneity of Abnormal Prion Protein (PrPSc) in Murine Scrapie Prions Determined by PrPSc-Specific Monoclonal Antibodies     

Yuko USHIKI-KAKU  Yoshihisa SHIMIZU  Naoko TABETA  Yoshifumi IWAMARU  Kiyoko OGAWA-GOTO  Shunji HATTORI  Takashi YOKOYAMA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2014,76(2):285-288

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Prevalence and Dynamics of Antibodies against NcSAG1 and NcGRA7 Antigens of Neospora caninum in Cattle during the Gestation Period     

Yasuhiro TAKASHIMA  Masaki TAKASU  Isao YANAGIMOTO  Naoki HATTORI  Tatiana BATANOVA  Yoshifumi NISHIKAWA  Katsuya KITOH 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2013,75(11):1413-1418

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Positive phototaxis as the cause of jaw malformations in larval greater amberjack,Seriola dumerili (Risso, 1810): Mitigation by rearing in tanks with low‐brightness walls     

Yoshifumi Sawada  Tsukasa Sasaki  Keisuke Nishio  Michio Kurata  Tomoki Honryo  Yasuo Agawa 《Aquaculture Research》2020,51(6):2261-2274

Jaw malformations are a serious problem in fingerlings of the greater amberjack, Seriola dumerili. To establish a countermeasure against these malformations, we conducted a larval behavioural test to identify their root cause, and we investigated the ability of low‐brightness rearing tank walls to control their occurrence. Larval distribution was examined in a horizontally illuminated rectangular transparent aquarium (20 cm × 100 cm × 25 cm), and their distribution was biased towards the light source after this lighting was provided from 3 to 13 days post hatching (dph), indicating positive phototaxis; this response disappeared on 22 dph (there are no data between 13 and 22 dph). Larvae were observed to swim phototactically towards the light source and repeatedly collided with the tank wall (walling behaviour). To investigate the ability of wall brightness to control the incidence of jaw malformations, we compared their incidence in a rearing trial with different Munsell colour values for the tank walls: 2.11 (black), 5.85 (grey) and 9.52 (white). The incidence rate of jaw malformations at 25 dph was significantly lower in the tanks with lower‐brightness walls, that is, 5.8%, 22.5% and 26.8% for black, grey and white respectively. Larval walling behaviour was most intense for white, followed in order by grey and black. These results indicate that positive phototaxis elicits larval walling behaviour, causing jaw malformations, and that low‐brightness tank walls control this process.  相似文献   

Optimal period for the effective promotion of initial swim bladder inflation in yellowfin tuna,Thunnus albacares (Temminck and Schlegel), larvae          下载免费PDF全文

Tomoki Honryo  Michio Kurata  Angel Guillen  Yoshiki Tamura  Amado Cano  Maria S Stein  Daniel Margulies  Vernon P Scholey  Yoshifumi Sawada 《Aquaculture Research》2017,48(10):5443-5446

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