Artificial burrow preference by the Japanese crayfish Cambaroides japonicus     

Kazuyoshi Nakata  Tatsuo Hamano  Ken-Ichi Hayashi  Tadashi Kawai  Seiji Goshima 《Fisheries Science》2001,67(3):449-455

SUMMARY: Preference for artificial burrows by the endangered Japanese crayfish species Cambaroides japonicus was studied to improve its cultivation. The occupation of artificial burrows, which were made from straight polyvinyl chloride pipes of different internal diameters ( Y , mm), by crayfishes of different total lengths ( X , mm) was significantly ( P < 0.001, n = 56) described by a linear regression: Y = 0.49 X + 3.42 (19.0 ≤ X ≤ 70.2). Among burrows of different lengths [crayfish total length (TL) × 1, × 2, × 3, and × 4], crayfishes significantly preferred burrows that were greater than TL × 3 ( P < 0.001, n = 588).  相似文献   

Discrimination of “grazing milk” using milk fatty acid profile in the grassland dairy area in Hokkaido          下载免费PDF全文

Tomohiro Mitani  Kuniyuki Kobayashi  Koichiro Ueda  Seiji Kondo 《Animal Science Journal》2016,87(2):233-241

Milk produced by the grazing system, referred to as “grazing milk” contains many components required for human health. The milk fatty acid (FA) profile is strongly associated with the diet on the farms. In the present study, based on the FA profile of farmer's bulk milk, we determined how to discriminate between milk produced on grazing and on a confinement system. A field survey was conducted four times (grazing and confinement season) in the Konsen (29 farms) and Okhotsk (25 farms) area in Hokkaido. Farmer's bulk milk samples and details of feeding management were collected and the FA profile of milk was measured. Milk produced during the grazing season contained less C16:0 and cis‐9 C16:0, and more C18:0, cis‐9 C18:1, trans‐11 C18:1, cis‐9,12 C18:2, cis‐9,trans‐11 C18:2 and cis‐9,12,15 C18:3 than milk produced during the confinement season. Discrimination analysis using 16 FA revealed that almost all milk samples were discriminated correctly (confinement season: 90% correct and 10% borderline, grazing season: 88% correct, 9% borderline and 3% incorrect). For farmers that were categorized incorrectly and were considered borderline in the grazing season, the dependency on pasture was low compared with that for farmers correctly discriminated. Therefore, to claim “grazing milk”, a high dependency on pasture is required for grazing dairy farmers.  相似文献   

Relationship of rumen fill and fermentation to diurnal and seasonal variation of herbage intake in dairy cows grazed on perennial ryegrass pasture          下载免费PDF全文

Koichiro Ueda  Tomohiro Mitani  Seiji Kondo 《Animal Science Journal》2016,87(9):1148-1156

To clarify the effect of digesta weight in the reticulorumen on diurnal and seasonal fluctuations in herbage intake, six ruminally cannulated, non‐lactating dairy cows were grazed on perennial ryegrass/white clover pasture during morning and evening sessions in spring and autumn. The digesta weight of fresh matter, dry matter (DM) and fiber in the reticulorumen at the beginning and the end of each grazing session was lower in spring than in autumn (P < 0.01). Although the digesta weight was similar between the sessions at the beginning of grazing, it was greater for the evening than for the morning at the end of grazing (P < 0.01). The large particles proportion in the digesta was lower for the morning than the evening (P < 0.01), and it was lower in spring than in autumn (P < 0.01). The concentrations of volatile fatty acids in rumen fluid were generally higher in spring compared with autumn. The herbage DM intake during the evening was greater compared with the morning in both seasons (P < 0.01). However, there was no difference in herbage DM intake between seasons. The results showed that the rumen digesta fill was not the sole factor explaining diurnal and seasonal variation of herbage intake in grazing dairy cows.  相似文献   

Herbage intake and ruminal digestion of dairy cows grazed on perennial ryegrass pasture either in the morning or evening          下载免费PDF全文

Koichiro Ueda  Tomohiro Mitani  Seiji Kondo 《Animal Science Journal》2016,87(8):997-1004

This study aimed to clarify diurnal fluctuations of herbage intake, ruminal fermentation of herbage carbohydrates and proteins, and digesta particulate weight in the rumen of grazing dairy cows. Six ruminally cannulated, non‐lactating dairy cows were grazed on perennial ryegrass/white clover pasture either in the morning (04.00 to 08.00 hours) or the evening (16.00 to 20.00 hours). Cows grazed in the evening spent more time (P < 0.01) and consumed more herbage (P < 0.01) compared with cows grazed in the morning. Higher (P < 0.05) daily mean concentrations of total volatile fatty acid, propionate and n‐butyrate in rumen fluid were observed for cows grazed in the evening compared with cows grazed in the morning. Although cows grazed in the evening ingested more crude protein compared with cows grazed in the morning, no significant difference in NH₃‐N concentration in rumen fluid was observed between them. The ratio of purine‐derivative concentration to creatinine concentrations was higher (P < 0.01) in the urine of cows grazed in the evening than in cows grazed in the morning. These results clearly indicated that evening grazing was advantageous for dairy cows compared with morning grazing, in terms of ruminal fermentable energy intake and nitrogen utilization efficiency.  相似文献   

Clinical pharmacokinetics of oseltamivir and its active metabolite oseltamivir carboxylate after oral administration in horses     

Yamanaka T  Yamada M  Tsujimura K  Kondo T  Nagata S  Hobo S  Kurosawa M  Matsumura T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2007,69(3):293-296

The aim of this study was to investigate the pharmacokinetics of oseltamivir carboxylate (OC) in horses (n=6) after oral administration of its prodrug oseltamivir. The binding rate of OC to horse plasma proteins was negligible (<1%). Oral administration of oseltamivir of 2 mg/kg body weight of oseltamivir to horses provided a plasma concentration of OC (mean maximum concentration: 257.9 ng/ml) above the inhibitory concentrations against equine influenza A viruses determined in vitro. However, because OC is rapidly eliminated from horse plasma (mean elimination half-life: 2.5 hr), administration intervals should be less than 10 hr to retain a suitable concentration when using a single dose of 2 mg/kg oseltamivir.  相似文献   

Relationship between soak time and number of enmeshed animals in experimentally lost gill nets     

Seiji Akiyama  Eriko Saito  Toshihiro Watanabe 《Fisheries Science》2007,73(4):881-888

In order to determine the effects of ghost fishing by lost gill nets, the relationship was examined between soak time and number of enmeshed animals in experimentally lost gill nets by using diving observations. Two experimental gill nets were set at 13 m depth in Tateyama Bay, Chiba Prefecture, Japan for approximately 200 days. One gill net was deployed in a small trough surrounded by artificial reefs, and the other was deployed on an adjacent open sandy bed. Twelve species of crustaceans, six species of gastropods, and five species of bony fish were enmeshed in the experimental gill nets. The number of enmeshed animals in the artificial reef gill net was substantially larger than that in the sandy bed gill net. The number of enmeshed animals in the experimental gill nets increased rapidly within one month after deployment, and then declined gradually showing fluctuations caused by the decrease in newly enmeshed animals, and the drop off from gill nets caused by the decomposition of dead animals. The decrease in the number of enmeshed animals was expressed by logarithmic equations, and based on these equations, the duration of capture function for the lost gill nets was calculated to be 284–561 days in the artificial reef gill net and 200 days in the sandy bed gill net. The duration of capture function for the lost gill nets for non-commercial by-catch species such as small crustaceans and gastropods was longer than for commercial species such as Japanese spiny lobster and bony fish.  相似文献   

Species identification method for <Emphasis Type="Italic">Scombrops boops</Emphasis> and <Emphasis Type="Italic">Scombrops gilberti</Emphasis> based on polymerase chain reaction-restriction fragment length polymorphism analysis of mitochondrial DNA     

Shiro Itoi  Noriyuki Takai  Satomi Naya  Keitaro Dairiki  Akira Yamada  Seiji Akimoto  Kiyoshi Yoshihara  Haruo Sugita 《Fisheries Science》2008,74(3):503-510

ABSTRACT:   Gnomefish Scombrops boops and Scombrops gilberti are commercially important fishes in Japan, but these species are often confused in the markets because of their morphological similarity. To identify these two species, we performed nucleotide sequencing and restriction fragment length polymorphism (RFLP) analysis on 16S ribosomal RNA (rRNA) gene and the control region in mitochondrial DNA. Five and 12 nucleotide substitutions were observed between species in the 777-bp 16S rRNA gene and 471-bp control region, respectively. Diagnostic restriction sites for discriminating between S. boops and S. gilberti were found in the 16S rRNA gene, but not in the control region. Polymerase chain reaction (PCR)–RFLP analysis using two enzymes, Eco NI and Mva I, clearly discriminated between S. boops and S. gilberti identified by meristic characters. The PCR–RFLP analysis identified most of the 168 Scombrops young caught in the coastal waters of the Izu and Miura peninsulas as S. boops , suggesting that S. gilberti juveniles are rare in this area.  相似文献   

Improvement in recruitment of Japanese sardine with delays of the spring phytoplankton bloom in the Sea of Japan          下载免费PDF全文

Taketoshi Kodama  Taku Wagawa  Seiji Ohshimo  Haruyuki Morimoto  Naoki Iguchi  Ken‐Ichi Fukudome  Tsuneo Goto  Motomitsu Takahashi  Tohya Yasuda 《Fisheries Oceanography》2018,27(4):289-301

To evaluate the impact of temporal variation of primary productivity on the recruitment of Japanese sardine (Sardinops melanostictus) in the Sea of Japan, the phenology of sea surface phytoplankton abundance was estimated from 8 day multiple satellite (SeaWiFS, MODIS‐Aqua, MERIS, and VIIRS) derived sea surface chlorophyll (SSChl) a concentrations from January 1998 to December 2015. Because relationships between SSChl a and in situ chlorophyll a concentrations were significantly different among periods based on the satellite combinations used, maximum and minimum SSChl a concentrations of 1 year were relativized as 1 and 0, respectively. Spatio‐temporal variation of relativized SSChl a concentrations was determined by using empirical orthogonal function (EOF) analysis. Scores in the first EOF mode denoted the basin‐scale variations of SSChl a concentrations in the Sea of Japan, and the major peak from the end of February to the end of May displayed the spring bloom. The logarithm of recruitment per spawner (LNRPS) for sardine was positively affected by delays in the start and end dates of the spring phytoplankton bloom. The delay of the date of the lowest sea surface temperature contributed to the delay of the end of the spring bloom during the period 1998–2015 and elevated the LNRPS during the period 1982–2015. Sardine spawns in the southern Sea of Japan from April to May, hence, delays of the spring bloom prolonged its overlap with sardine larval periods, and thus improved the recruitment of Japanese sardine in the Sea of Japan.  相似文献   

Risk assessment of nitrate pollution in groundwater based on the environmental nitrogen-assimilation capacity of agricultural lands in Hokkaido     

Takehiko MATSUMOTO  Seiji TOU 《Soil Science and Plant Nutrition》2006,52(2):251-252

(pp. 17–24)
A trial calculation was performed of the environmental nitrogen-assimilation capacity and the amount of nitrogen input based on various statistical data, which were compiled from each city, town and village in Hokkaido prefecture. The relationship between the excess quantity of nitrogen, after nitrogen input, and the environmental nitrogen-assimilation capacity and the nitrate-nitrogen concentration of the groundwater was considered.
Environmental nitrogen-assimilation capacity = nitrogen output by the crops + acceptable level of residual nitrate in the soil profile.*
^*It is calculated by the amount of nitrate precipitation evapotranspiration ×10 mg L⁻¹.

• 1) 

  The average value of the environmental nitrogen-assimilation capacity in Hokkaido Prefecture was observed to be 183 kg ha⁻¹. The maximum and minimum values of the environmental nitrogen-assimilation capacity were 308 kg ha⁻¹ and 94 kg ha⁻¹, respectively. When the average value of the environmental nitrogen-assimilation capacity with respect to main agricultural land use was compared across municipalities, it was largely in the following order · grassland (218 kg ha⁻¹), upland (169 kg ha⁻¹), and paddy land (157 kg ha⁻¹).

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