Endocrine status and development of porcine testicular tissues in host mice     

Kaneko H  Kikuchi K  Nakai M  Noguchi J 《The Journal of reproduction and development》2008,54(6):480-485

Clarification of the endocrine status of host mice provides us with basic knowledge with which we can manipulate the growth and function of xenografted testicular tissues. We investigated the hormonal profiles of castrated mice grafted with porcine immature testicular tissues from 30 to 210 or more days after grafting (day 0=castration and grafting). The serum follicle stimulating hormone (FSH) concentrations of the host mice declined (P<0.05) from day 60 compared with those of the castrated, ungrafted mice. The serum inhibin and testosterone levels were higher (P<0.05) than those in the castrated, ungrafted mice from days 30 and 90 days, respectively. The inhibin levels further increased (P<0.05) from day 90, during which time the levels were higher (P<0.05) than those in the intact male mice. In the grafts, formation of lumens occurred in the seminiferous cords on day 90 and spermatozoa appeared in the lumens from day 120. However, spermatogenesis in the grafts did not reach the qualitatively normal levels observed in adult boars. The intensity of the immune reaction to inhibin alpha subunits in the Sertoli cells of the grafts decreased with differentiation of the seminiferous tubules. The present findings indicate that a feedback loop was established between the mouse hypothalamo-pituitary axis and the grafted porcine tissues from 60 days post-grafting. The results also indicate that the serum inhibin levels in the host mice remained high even after the appearance of lumens in the seminiferous tubules of the grafted tissues; this is strikingly different to the situation in normal male animals, in which the serum inhibin levels decline at around the time of tubular differentiation. The lack of efferent ducts in the tubules of the grafted tissues probably caused the accumulation of inhibin to be released into the lumens, resulting in high concentrations of circulating inhibin. These high levels of inhibin may directly affect spermatogenic activity and suppress FSH secretion.  相似文献   

Relationships among age, body weight, scrotal circumference, semen quality and peripheral testosterone and estradiol concentrations in pubertal and postpubertal Holstein bulls     

Devkota B  Koseki T  Matsui M  Sasaki M  Kaneko E  Miyamoto A  Amaya Montoya C  Miyake Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2008,70(1):119-121

In the present study, the correlations among age, body weight, scrotal circumference (SC), semen quality and peripheral testosterone and estradiol-17beta (E(2)) concentrations were investigated in pubertal (n=5) and postpubertal (n=7) groups of Holstein bulls over a 6 week period. There were significant positive correlations (P<0.01) among age, body weight and SC in both groups, and similar significant correlations between sperm motility and SC in pubertal bulls (P<0.01) and between sperm concentration and SC in postpubertal bulls (P<0.05). The sperm motility after collection (P<0.05) and after freezing and thawing (P<0.01) of the postpubertal bulls correlated positively with the E(2) concentration. Estrogen may be important for the function of postpubertal bull testes, in which it may regulate spermatozoa motility in vivo.  相似文献   

Selected Aspects of Advanced Porcine Reproductive Technology     

K Kikuchi  N Kashiwazaki  T Nagai  M Nakai  T Somfai  J Noguchi  H Kaneko 《Reproduction in domestic animals》2008,43(S2):401-406

In vitro fertilization (IVF) of in vitro matured (IVM) oocytes in pigs has become the most popular method of studying gametogenesis and embryogenesis in this species. Furthermore, because of recent advances in in vitro culture (IVC) of IVM–IVF embryos, in vitro production (IVP) of embryos now enables us to generate viable embryos as successfully as for in vivo -derived embryos and with less cost and in less time. These technologies contribute not only to developments in reproductive physiology and agriculture but also to the conservation of porcine genetic resources and the production of cloned or genetically modified pigs. However, in IVP, there still remains the problem of abnormal ploidy, which is caused by performing procedures under non-physiological conditions. In recent years, unique technologies such as intracytoplasmic sperm injection (ICSI) or xenografting of gonadal tissue into immunodeficient experimental animals have been developed to help conserve gamete resources. These technologies combined with IVP are expected to be useful for the conservation of gametes from important genetic resources. Here, we discuss the developmental ability and normality of porcine IVP embryos and also the utilization of ICSI and xenografting in advancing biotechnology in pigs.  相似文献   

Sucrose assists selection of high‐quality oocytes in pigs          下载免费PDF全文

Thanh Quang Dang‐Nguyen  Hiep Thi Nguyen  Tamas Somfai  David Wells  Nguyen Thi Men  Nguyen Viet‐Linh  Junko Noguchi  Hiroyuki Kaneko  Kazuhiro Kikuchi  Takashi Nagai 《Animal Science Journal》2018,89(6):880-887

We investigated whether high‐quality in vitro matured (IVM) oocytes can be distinguished from poor ones based on the morphological changes after treatment with hyperosmotic medium containing 0.2 mol/L sucrose in pigs. We hypothesize that IVM oocytes maintaining round shape have higher quality than mis‐shapened oocytes following dehydration. Oocyte quality was verified by determining embryonic developmental competence using in vitro fertilization, nuclear transfer and parthenogenetic activation. In all cases, the round oocytes had greater (p < .05) developmental competence than that of mis‐shapened oocytes in terms of blastocyst rate and total cell number in blastocysts obtained after 6 days of in vitro culture. We also confirm that round aged oocytes are higher in quality than mis‐shapened aged oocytes. In an attempt to find out why high‐quality oocytes maintain a round shape whereas poorer oocytes become mis‐shapened following sucrose treatment, we examined the arrangement of actin microfilaments and microtubules. Abnormal organization of these cytoskeletal components was higher (p < .05) in mis‐shapened oocytes compared to round oocytes after 52 hr of IVM. In conclusion, sucrose treatment helps selection of high‐quality oocytes, including aged oocytes, in pigs. Abnormal cytoskeleton arrangements partly explain for low developmental competence of mis‐shapened oocytes.  相似文献   

Simultaneous evaluation of spatial working memory and motivation by the allocentric place discrimination task in the water maze in rats.     

T Kikusui  T Tonohiro  T Kaneko 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1999,61(6):673-681

In order to evaluate learning and memory deficits separately from and simultaneously with motivational, motor and sensory impairments in identical animals, we developed the allocentric place discrimination task test using a water maze in rats. For this assessment task, two similar, visible platforms, one was fixed and the other was floating, were simultaneously present in a pool, and the working memory of the allocentric place discrimination task was evaluated. After training, the task accuracy was high about 85% correct and animals were used repeatedly. The accuracy decreased significantly when the pool was surrounded with a black curtain. Muscarinic receptor antagonist scopolamine 0.5 mg/kg selectively impaired the accuracy. Muscle relaxant dantrolene 10 mg/kg selectively decreased swimming speed. Under low motivational condition (warm water), still time increased and swimming speed decreased, but the accuracy was not affected. Similar to warm water, opioid receptor agonist morphine 15 mg/kg increased still time and decreased swimming speed. These results suggest that the allocentric place discrimination task is useful in evaluating spatial working memory ability independently of and concurrently with also visual, motor ability and motivation in identical animals.  相似文献   

Prevalence and persistence of Salmonella in broiler chicken flocks.   总被引：2，自引：0，他引：2  

S Limawongpranee  H Hayashidani  A T Okatani  K Ono  C Hirota  K Kaneko  M Ogawa 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1999,61(3):255-259

Cecal contents of 2,345 broiler chickens consisting of 28 flocks originated from 12 farms were examined for the prevalence of Salmonella to know the actual status of infection with Salmonella in the chicken flocks. Salmonella was isolated from 336 (14.3%) samples. From these isolates, eight serovars were identified. Of the 336 Salmonella isolates, 242 (72.0%) were serotyped as S. Blockley, 60 (17.9%) S. Hadar, 15 (4.5%) S. Bredeney, nine (2.7%) S. Schwarzengrund, four (1.2%) S. Anatum, three (0.9%) S. Enteritidis, two (0.6%) S. Ohio, and one (0.3%) S. Livingstone. The same serovars of Salmonella were repeatedly found in the chickens from the same farms. S. Typhimurium and S. Enteritidis were detected in pooled broken eggshell samples collected from the hatchery. Analysis of plasmid profiles revealed 11 patterns of S. Blockley and seven patterns of S. Hadar. Strains of the same plasmid profiles of S. Blockley were isolated repeatedly from the same farm over one year after the first isolation.  相似文献   

Effects of photoperiod on survival and growth of the marine pejerrey Odontesthes argentinensis larvae     

Luciano Siqueira Freitas  Ricardo Vieira Rodrigues  Marcelo Hideo Okamoto  Luiz Roberto Louzada  & Luís André Sampaio 《Aquaculture Research》2009,40(2):252-255

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Reduced sensitivity to fenarimol in Japanese field strains of Venturia nashicola     

Yasunori Tomita  Hideo Ishii 《Pest management science》1998,54(2):150-156

Monoconidial strains of Venturia nashicola Tanaka et Yamamoto were isolated from Japanese or Chinese white pear trees which had never been treated with sterol demethylation inhibitors (DMIs) and their baseline sensitivities to fenarimol were determined by mycelial growth tests on fungicide-amended culture media. Strains were also obtained from Japanese pear orchards, which had been intensively treated with DMIs for several years and monitored for the shifts of fenarimol sensitivity in comparison with the baseline sensitivity. Results suggested slight shifts to lower fenarimol sensitivity in strains isolated from DMI-treated Japanese pear orchards. However, in inoculation tests on pear seedlings, fenarimol still provided adequate control of V. nashicola strains with reduced sensitivity to fenarimol in vitro, suggesting that the performance of this fungicide will still be maintained in the field. © 1998 Society of Chemical Industry  相似文献   

Assessing sexual maturity of feminized Japanese eel Anguilla japonica by measuring eye size     

Akihiro Okamura  Hideo P. Oka  Noriyuki Horie  Tomoko Utoh  Yoshiaki Yamada  Naomi Mikawa  Satoru Tanaka  Katsumi Tsukamoto 《Aquaculture International》2009,17(1):91-99

For efficient production of Japanese eel Anguilla japonica eggs, knowledge of the status of the sexual maturity of potential broodstock females is important because this status directly influences the time required to produce mature eggs by successive hormone doses. Here we apply an eye index (relative eye size) to evaluate the gonadal status of feminized A. japonica, which were induced by administration of estradiol-17β. Examination of gonad somatic and eye indexes of 267 feminized eels, cultivated for 12–56 months, revealed a significant correlation between these two indexes. Artificial maturation of 35 feminized eels showed that the number of hormone injections administered before ovulation was significantly lower as the eye index score increased, indicating availability of this noninvasive method of predicting sexual maturity of feminized eel. There was no correlation between eye index and fertilization rate, hatching rate, or larval survival rate, suggesting that sexual maturity before hormonal treatment does not affect egg quality.  相似文献   

Ontogenetic changes of feeding habits of larval jack mackerel <Emphasis Type="Italic">Trachurus japonicus</Emphasis> in the Kuroshio frontal area of the southern East China Sea     

Yuuichi Hirota  Hitoshi Honda  Hideo Sakaji  Shinji Uehara  Tadafumi Ichikawa 《Fisheries Science》2016,82(4):573-583

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