Partial characterization and ontogenetic development of pancreatic digestive enzymes in Japanese eel Anguilla japonica larvae     

Koji Murashita  Hirofumi Furuita  Hiroyuki Matsunari  Takeshi Yamamoto  Masahiko Awaji  Kazuharu Nomura  Jiro Nagao  Hideki Tanaka 《Fish physiology and biochemistry》2013,39(4):895-905

The pancreatic digestive enzymes, trypsin, chymotrypsin, lipase and amylase were partially characterized, and changes in their activities were examined during the initial ontogeny of Japanese eel Anguilla japonica larvae from 5 to 34 days post-hatching (dph). The pH optima of the eel larval enzymes were narrower than those other fish species; trypsin activity was highest at pH 9, chymotrypsin and amylase activities were highest at pH 7 and 8, and lipase activity was highest at pH 8 and 9. In an analysis of thermal profiles, the larval pancreatic enzymes had a high optimal temperature and high thermal stability, which are typical of fish from the tropics. At 12 and 13 dph, lipase activity and gene expression levels of trypsin (-a and -b), lipase and amylase decreased markedly, suggesting a marked change in larval metabolism at that time. These data could be useful in the development of artificial larval diets in Japanese eel.  相似文献   

Effects of docosahexaenoic acid on growth,survival and swim bladder inflation of larval amberjack ( Seriola dumerili, Risso)     

Hiroyuki Matsunari  Hiroshi Hashimoto  Kentaro Oda  Yoshitsugu Masuda  Hitoshi Imaizumi  Kazuhisa Teruya  Hirofumi Furuita  Takeshi Yamamoto  Kazuhisa Hamada  Keiichi Mushiake 《Aquaculture Research》2013,44(11):1696-1705

The effect of docosahexaenoic acid (DHA) on the growth performance, survival and swim bladder inflation of larval Seriola dumerili during the rotifer feeding period was investigated in two feeding experiments. Amberjack larvae at 3 day post hatching were fed rotifers enriched with (1) freshwater C hlorella (Chlo), (2) a mixture (2:1, v/v) of Chlo and DHA‐enriched C hlorella (DHA‐Chlo), (3) DHA‐Chlo and (4) DHA‐Chlo and commercial DHA emulsion, in triplicate for 7 days. The average DHA contents of the rotifers were 0.0, 0.4, 1.0 and 1.9 mg g^?1 DM respectively. The survival rate was improved by the enrichment of rotifers with DHA‐Chlo alone, and DHA‐Chlo and emulsion. Growth and swim bladder inflation of fish fed rotifers enriched with DHA‐Chlo were significantly (P < 0.05) improved, however, with increased levels of DHA further improvement was not found. DHA content in the larval whole body proportionally increased with the DHA level in the rotifers. These results suggest that DHA enrichment of rotifers is effective to improve the growth, survival rate and swim bladder inflation of amberjack larvae. The DHA requirement of amberjack larvae is estimated to be 1.5 mg g^?1 on a dry matter basis of rotifers.  相似文献   

Growth performance and physiological condition of F1 amago salmon Oncorhynchus masou ishikawae juveniles obtained from broodstock with selective breeding for growth on a low fish-meal diet     

Takeshi Yamamoto  Hiroyuki Okamoto  Hirofumi Furuita  Koji Murashita  Hiroyuki Matsunari  Yasuro Iwashita  Shunji Amano  Nobuhiro Suzuki 《Fisheries Science》2014,80(3):569-579

A 10-week feeding trial was conducted to evaluate the growth and physiological condition of F1 amago salmon Oncorhynchus masou ishikawae juveniles obtained from broodstock that had been selected for growth on a low fish-meal (LFM) diet. F1 juveniles from broodstock showing superior or inferior growth on a LFM diet (LFM-S, LFM-I), and those from broodstock showing intermediate growth on a fish meal-based (FM) diet (FM-M), were fed a LFM diet and a FM diet. In fish fed the LFM diet, growth of LFM-S was significantly better than FM-M at 3 weeks; however, this superiority in growth disappeared at the end of the 10-week trial. Growth of LFM-I was significantly lower than LFM-S throughout the feeding trial. Growth of fish fed the FM diet was not significantly different among groups, and higher than fish fed the LFM diet. Improvements in the blood hemoglobin concentration and morphological conditions of the distal intestine and liver were observed in LFM-S fed the LFM diet. Although the effect of selective breeding was limited in F1 amago salmon, the present results suggest that continuous selection for growth with a LFM diet has potential as a method to adapt to the limited supply of fish meal.  相似文献   

Characterization and ontogenetic development of digestive enzymes in Pacific bluefin tuna Thunnus orientalis larvae     

Koji Murashita  Hiroyuki Matsunari  Kazunori Kumon  Yosuke Tanaka  Satoshi Shiozawa  Hirofumi Furuita  Hiromi Oku  Takeshi Yamamoto 《Fish physiology and biochemistry》2014,40(6):1741-1755

The major digestive enzymes in Pacific bluefin tuna Thunnus orientalis larvae were characterized, and the physiological characteristics of the enzymes during early ontogeny were clarified using biochemical and molecular approaches. The maximum activity of trypsin (Try), chymotrypsin (Ct) and amylase (Amy) was observed at pH 6–11, 8–11 and 6–9, respectively. Maximum activity of Try, Ct and Amy occurred at 50 °C, that of lipase (Lip) was at 60 °C and that of pepsin (Pep) was at 40–50 °C. These pH and thermal profiles were similar to those for other fish species but differed from those previously reported for adult bluefin tuna. Enzyme activity for all enzymes assayed was found to decrease at high temperatures (Try, Ct, Amy and Pep: 50 °C; Lip: 40 °C), which is similar to findings for other fish species with one marked exception—increased Try activity was observed at 40 °C. Lip activity appeared to be dependent on bile salts under our assay conditions, resulting in a significant increase in activity in the presence of bile salts. Ontogenetic changes in pancreatic digestive enzymes showed similar gene expression patterns to those of other fish species, whereas marked temporal increases in enzyme activities were observed at 10–12 days post hatching (dph), coinciding with previously reported timing of the development of the pyloric caeca in bluefin tuna larvae. However, complete development of digestive function was indicated by the high pep gene expression from 19 dph, which contradicts the profile of Pep activity and previously reported development timing of the gastric gland. These findings contribute to the general knowledge of bluefin tuna larval digestive system development.  相似文献   

Disparities in activity levels and learning ability between Djungarian hamster (Phodopus sungorus) and Roborovskii hamster (Phodopus roborovskii)          下载免费PDF全文

Hiromi Ikeda  Mao Nagasawa  Takeshi Yamaguchi  Kimie Minaminaka  Ryosei Goda  Vishwajit S. Chowdhury  Shinobu Yasuo  Mitsuhiro Furuse 《Animal Science Journal》2017,88(3):533-545

The Djungarian hamster and the Roborovskii hamster belong to the same genus of Phodopus. However, the Djungarian hamster is tame and shows sedative behavior, while Roborovskii hamster is not tame and shows high levels of locomotor activity. Hyperactivity occurs in animals with tameless behavior. Tameness or tamelessness behavior is very important because tameness helps for breeding and controlling as well as it enables a strong human‐animal bond. In the present study, we examined the relationships between activity levels and cognitive function in Djungarian and Roborovskii hamsters. Three types of behavioral tests were performed to analyze their activity levels, memory and leaning ability. The levels of L‐ and D‐amino acids and monoamines in the brain were then determined. Roborovskii hamsters showed significantly higher locomotor activity than Djungarian hamsters. Memory ability was not significantly different between the two hamsters, but Roborovskii hamsters showed lower learning ability. Brain levels of D‐serine which is related to enhancement in memory and learning ability, were significantly higher in Djungarian hamsters, but the reverse was true for brain dopamine and serotonin levels. These results suggest that these differences in brain metabolism may be related to the behavioral differences between the two hamsters.  相似文献   

Improved porcine model for Shiga toxin‐producing Escherichia coli infection by deprivation of colostrum feeding in newborn piglets          下载免费PDF全文

Toshio Sato  Takashi Hamabata  Eiji Takita  Takeshi Matsui  Kazutoshi Sawada  Taishi Imaoka  Nobuo Nakanishi  Keizo Nakayama  Takamitsu Tsukahara 《Animal Science Journal》2017,88(5):826-831

Porcine edema disease (ED) is a toxemia caused by enteric infection with Shiga toxin 2e (Stx2e)‐producing Escherichia coli (STEC). ED occurs most frequently during the weaning period and is manifested as emaciation associated with high mortality. In our experimental infection with a specific STEC strain, we failed to cause the suppression of weight gain in piglets, which is a typical symptom of ED, in two consecutive experiments. Therefore, we examined the effects of deprivation of colostrum on the sensitivity of newborn piglets to STEC infection. Neonatal pigs were categorized into two groups: one fed artificial milk instead of colostrum in the first 24 h after birth and then returned to the care of their mother, the other breastfed by a surrogate mother until weaning. The oral challenge with 10¹¹ colony‐forming units of virulent STEC strain on days 25, 26 and 27 caused suppression of weight gain and other ED symptoms in both groups, suggesting that colostrum deprivation from piglets was effective in enhancing susceptibility to STEC. Two successive STEC infection experiments using colostrum‐deprived piglets reproduced this result, leading us to conclude that this improved ED piglet model is more sensitive to STEC infection than the previously established models.  相似文献   

Bacterial community incorporating carbon derived from plant residue in an anoxic non-rhizosphere soil estimated by DNA-SIP analysis     

Chol Gyu Lee  Takeshi Watanabe  Susumu Asakawa 《Journal of Soils and Sediments》2017,17(4):1084-1091

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Erratum to: Emulating natural disturbances: the role of silviculture in creating even-aged and complex structures in the black spruce boreal forest of eastern North America     

Takeshi Tange 《Journal of Forest Research》2010,15(1):81-81

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The smell and odorous components of dried shiitake mushroom, Lentinula edodes VI: increase in odorous compounds of dried shiitake mushroom cultivated on bed logs     

Masakazu Hiraide  Tadakazu Nakashima  Takeshi Fujiwara 《Journal of Wood Science》2010,56(6):483-487

Odor is one of the most important characteristics affecting consumer preference for dried shiitake mushrooms [Lentinula edodes (Berk.) Pegler]. In our previous studies, we found that the odor content of commercial dried products was too weak for most people, and that the odorous compound content could be increased by adding amino acids to sawdust media. Currently, however, bed-log cultivation is used to produce fruiting bodies for dried products. The purpose of this study was to fi nd a method to increase the content of odorous compounds in dried products cultivated on bed logs. Pressure injection of amino acids from the side of the bed log was the most effi cient method, but it had some problems. Hence, a simpler and less troublesome method was developed, i.e., injecting amino acid solution from small bottles set in deep holes bored in the sides of the bed logs. In fruiting bodies cultivated on bed logs injected with amino acid solution by the improved method, the mean contents of lentinic acid, a precursor of the odorous compound lenthionine, approximately doubled compared to that in the untreated logs, although the infi ltration area of the solution injected by the improved method was smaller than that by the former method.  相似文献   

Comparing the carbon sequestration capacity of temperate deciduous forests between urban and rural landscapes in central Japan     

M.A. Awal  Takeshi Ohta  Kazuho Matsumoto  Tae Toba  Kenichi Daikoku  Shigeaki Hattori  Tetsuya Hiyama  Hotaek Park 《Urban Forestry & Urban Greening》2010,9(3):261-270

Urbanisation is increasing tremendously in some parts of the world. Consequently, many rural forests may become depleted, although many opportunities exist for urban forests to increase. However, few studies have quantified the carbon (C) sequestration capacities of urban and rural forests in specific climatic zones. The present study compared carbon sequestration in two temperate deciduous forests located in Nagoya and Toyota, central Japan. The Nagoya University forest represented an urban forest, and a site in Toyota represented a rural forest. The urban forest at Nagoya University had comparatively smaller areas of green space and larger areas of buildings and roads. Land uses for building and road, which are typical of urban areas, result in smaller diurnal temperature ranges but higher air temperature, vapour pressure deficit, and atmospheric carbon dioxide (CO₂) concentration. The urban forest in this study exhibited higher gross ecosystem exchange (GEE), especially in the active growing season from May to September, suggesting the possible effect of CO₂ fertilisation. However, higher air temperatures caused comparatively smaller net ecosystem exchange (NEE) because of higher ecosystem respiration (RE). Although both forests functioned as CO₂ sinks at annual time scales, the rural Toyota forest site (5.43 t C ha^–1 yr^–1) had 36% higher net ecosystem production (NEP=–NEE; the negative sign indicates uptake by the forest ecosystem from the atmosphere) than that at the urban forest. The higher normalised respiration (i.e., RE/GPP ratio; GPP=–GEE where GPP represents gross primary production) at the Nagoya University forest might be attributable to factors associated with the degree of urbanisation. Thus, in temperate forests, factors associated with urbanisation may reduce the atmospheric carbon sink function by accelerating respiration. This is an issue of global interest, as many countries are experiencing rapid urbanisation.  相似文献