首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Histological analysis of the gonadal development of Leporinus copelandii Steindachner, 1875, a rheophilic Characiformes species in the Paraiba do Sul River, South‐eastern Brazil, was described. We expect that this species adapt gonadal development to succeed in this river basin that has its longitudinal profile blocked by several impoundments. Fishes were examined by routine macroscopic and histological techniques. Stages of oocyte and spermatocyte development were described, and gonadal maturation was proposed. Mean oocyte diameter obtained from histological observations increased from the pre‐spawning (4.2–175.5 μm) to spawning (148.5–262.0 μm) phases, followed by a sharp decrease in the post‐spawning (27.0–56.7 μm) phase. Based on occurrence of different oocytes phases and oocyte size distribution, this species has group‐synchronic development of oocytes. Further studies are necessary to clarify the spawning grounds for L. copelandii in the Paraíba do Sul River basin, especially considering that several impoundments obliterate the natural river course and this could limit spawning grounds.  相似文献   

2.
The identification of 163 strains of Mycobacterium bovis by polymerase chain reaction (PCR) and microbiological tests was carried out on 252 tuberculous‐like lesions (TLLs) collected from slaughtered cattle in south‐east Brazil. This study compared the usefulness of three genotyping techniques, IS6110‐restriction fragment length polymorphism (RFLP), polymorphic guanine‐cytosine‐rich sequence (PGRS)‐RFLP and direct repeat (DR)‐spoligotyping, as applied to M. bovis isolates. Based on IS6110‐RFLP genotyping we selected a group of 23 isolates containing more than one IS6110 copy, along with 16 samples containing one IS6110 copy from different geographical areas, evenly distributed among dairy (eight) and beef cattle (eight). These selected isolates were analysed by PGRS‐RFLP and DR‐spoligotyping genotyping. Dairy cattle (17%) display a higher frequency of multiple IS6110 copies than beef cattle (10%). A comparison between the genotype data obtained fails to show a correlation between the main clusters found by the three techniques. However, the clustering of each genotyping procedure revealed that the majority of strains are closely related. The RFLP‐PGRS patterns showed a sizable group (20.5%) containing a 5.5 kb fragment and the predominant spoligotype is similar to that from the BCG vaccine strain. Unexpectedly, four strains (2.4%) showed drug resistance to 0.2 μg/ml isoniazid and 20 μg/ml ethionamide, but none of them was resistant to rifampicin or other antibiotics tested.  相似文献   

3.
Yellowish myotis, Myotis levis, is a seasonal, epididymal sperm‐storing Neotropical vespertilionid. In the dry season, males show simultaneous testis regression and sperm storage in cauda epididymis, enabling them to mate during this season. In this study, we investigated seasonal variations in body mass, diameter and height of seminiferous tubules and nuclei of Leydig cells in a population of southeastern Brazil. We also determined the frequencies of the stages of the seminiferous epithelium cycle (SEC) of mature individuals of this population. Body mass and diameter of Leydig cell nuclei showed no significant differences between dry and rainy seasons and stages of annual reproductive cycle; however, all other morphometric parameters varied significantly. The relative cumulative frequency of pre‐meiotic stages of the SEC (1–3) was 51%, of meiotic stage (4) was 2% and of post‐meiotic stages (5–8) was 47%. We confirmed that the yellowish myotis presents seasonal sperm production as revealed by testis regression and epididymal sperm storage during the dry season.  相似文献   

4.
A biometrical study of female porcine reproductive tracts recovered after slaughter was carried out. Sizes and weights of the various areas from one hundred eighty-seven sow tracts, eighty-one pre-puberal gilts and thirty-two puberal gilts were recorded. A table of abnormalities observed in examination of the sow tracts is also presented.  相似文献   

5.
Platelet‐activating factor (PAF) is a potent lipid mediator produced by various cell types of mammals and is involved in an inflammatory‐like process with increased vascular permeability. Platelet‐activating factor exerts its actions through the activation of specific PAF receptors (PAF‐R) found in cells and tissues of the female reproductive tract. The aim of this article was summarized briefly in the current research on the role of PAF in female reproductive functions. Platelet‐activating factor has been implicated in processes of ovulation, implantation and parturition because of its angiogenic and growth factor properties. This factor is influenced by ovarian steroid hormones in bringing about changes in the uterus and is a candidate molecule for initial embryo–maternal dialogue. Tissue concentrations of PAF are regulated by the equilibrium between biosynthesis and degradation by PAF‐acetylhydrolase (PAF‐AH). Antagonists of PAF interfere with ovulation and implantation. Platelet‐activating factor, its receptor, and PAF‐AH activity play an important role in the maintenance of pregnancy.  相似文献   

6.
The Brazilian Amazon is endemic for malaria and natural infections by Plasmodium spp. have been detected in Neotropical primates. Despite the diversity of primate species in the region, studies on infections by these agents are limited. The aim of the present study was to investigate the frequency of infection by Plasmodium vivax and P. falciparum in free‐born primates that were kept in captivity, in the western Amazon, Brazil. Blood samples were collected from 98 Neotropical primates. Detection of P. vivax and P. falciparum DNA was performed using a semi‐nested PCR, and the amplified products were sequenced. Plasmodium spp. DNA was detected in 6.12% (6/98) of the primates. P. vivax, and P. falciparum DNA was detected in 2.04% (2/98) and 4.08% (4/98) of these mammals, respectively. Sequencing and phylogenetic analysis confirmed the results obtained from the semi‐nested PCR. The presence of infected non‐human primates (NHP) can be auxiliary in the maintenance of P. falciparum and P. vivax and may have implications for the malaria surveillance and control in the Brazilian Amazon. It is necessary to structure an efficient surveillance system for the aetiological agents of malaria that infect NHP and humans to reduce the risk of Plasmodium spp. introduction into new areas, to protect all susceptible species.  相似文献   

7.
In this study, the annual cycle of the gonadal steroids testosterone (T), 11‐ketotestosterone (11‐KT), 17β‐oestradiol (E2) and 17α, 20β‐dihydroxy‐4‐pregnen‐3‐one (DHP) was determined using radioimmunoassay and then compared, for XY males (n = 35) and sex‐reversed XX males (n = 27) rainbow trout, to establish possible endocrinology differences. Both in XY males and sex‐reversed XX males, significant correlation was shown between body weight and T (r = 0.5046 and 0.34078, respectively; p < 0.0001) or KT (r = 0.52494 and 0.43545, respectively; p < 0.0001) concentrations. Plasma androgen levels in XY and sex‐reversed XX males were similar and showed an intense seasonal variation. The highest levels for T and 11‐KT were detected from December to April with a peak in January (51.67 ± 5.11 and 61.95 ± 4.25 ng/ml, for XY males and 57.1 ± 5.82 and 59.27 ± 4.84 ng/ml, respectively, for XX males). In addition, there was a positive correlation (p < 0.0001) between T and 11‐KT levels for XY males (r = 0.7533) and sex‐reversed XX males (r = 0.6019). Concentrations of DHP in XY males also showed seasonal variation with a peak in February (25.18 ± 12.99 ng/ml). However, DHP levels in sex‐reversed XX males were undetectable (<0.1 ng/ml) over the year. Levels of E2 were undetectable through the year in both groups of trout. In conclusion, the androgenic and oestrogenic profiles of sex‐reversed XX males were similar to those observed in XY males. The only difference in the annual gonadal steroid cycle between XY and sex‐reversed XX males was in the DHP profile.  相似文献   

8.
9.
10.
11.
Forest destruction has progressively hampered the survival of many species, and this is why it is so important to study of the lives of primates in captivity. This study aimed to describe the morphological aspects of the female reproductive tract of Sapajus apella. We used five animals obtained from the National Primate Center, Ananindeua – PA. The ovaries were paired, compact and symmetrical and had a smooth surface. The uterine tubes were bilateral and convoluted in adult animals and straight in young individuals. The uterus was simple and located in the pelvic region. The vagina was a long structure due to the position of the uterus. The external genitalia were located in the urogenital perineum and consisted of dark pigmented labia majora and labia minora, a vaginal vestibule as long as the vagina and a well‐developed clitoris. The results showed that the genitals of S. apella resemble those of other Neotropical primates.  相似文献   

12.
The leucocytic picture in 90 mature, healthy dromedary-cows, representing the different reproductive phases, as well as, the non-cyclic one, was determined. The non-cyclic camels possess high total leucocytic count (15.5 × 10 3 /cm 3 ) compared with other ruminants. Moreover, neutrophilic domination (58.7%) with increased N / L ratio (1.5) in camels is not typical for other quadrupeds. At oestrus, there was a mild neutrophilia, eosinopenia and lymphopenia (61.1%, 0,4% and 37,4%, respectively versus respective values of 58.7%, 0, 7% and 39, 7% in non-cyclic camels). However, the total number of leucocytes was reduced (13.7 vs. 15.5 × 10 3/ cm 3 ). A steady neutrophilia, eosinophilia and lymphopenia was associated with advancement of gestation in camels. An exceptional transient leucocytosis (P<0.05), with elevation in the lymphocyte proportion, occurred during the 9 th and 10 th month. At the preparturient period, a significant (P < 0.01) leucopenia, with neutrophilia (P < 0.01), lymphopenia (P < 0.05), and eosinopenia were reported. During early puerperium, the dromedary's leucogram revealed a typical moderate hematologic response to stress, manifested by lymphopenia (P < 0.01), eosinopenia (P < 0.05) and neutrophilia (P < 0.01) resulting in leucocytosis (P < 0.05 ).  相似文献   

13.
In recent years, habitat degradation led to the decline of some populations of brown‐throated sloth. The aim of this study was to describe morphological features of the female reproductive system of the species. The oval ovaries were partially surrounded by ovarian bursa. An external cortex and an inner medulla were present. Corpora lutea and corpora albicans together with follicles at various stages of development each with a single oocyte were found in the cortex. Uterine tubes were tortuous, tubular, travelled around the perimeter of the ovary and possessed a folded mucosa with ciliated pseudostratified epithelium. Uterus was simplex, with no horns and divided into three parts: a pear‐shaped cranial segment and a long caudal uterine segment (both forming the body of the uterus) and two cervices. Uterus presented three layers: mucosa, lined by pseudostratified epithelium, muscular and serosa. The cervices connected the uterus to the urogenital sinus, a distensible cavity with longitudinal mucosal folds lined by transitional epithelium that extended from the external urethral orifice and the external uterine ostia to the vulva, which was lined by a keratinized stratified squamous epithelium. Brown‐throated sloth presented a bipartite clitoris with paired crura, bodies and glandes. The presence of a double cervix and a bipartite clitoris was unique features of the species.  相似文献   

14.
15.
16.
17.
The physiological distribution of mast cells (MCs) in the reproductive tract and ovary of 12 Angora goats was determined using light microscopic histochemical techniques. Uterus (corpus uteri and cornu uteri), uterine cervix, uterine tubes (isthmus and ampulla) and ovary samples were obtained by laparatomy from groups of animals during metoestrus, dioestrus and proestrus (days 5, 10 and 16 of the oestrous cycle). Tissues were fixed in Mota's fixative (basic lead acetate) for 48 h and embedded in paraffin. Six-micrometre-thick sections were stained with toluidine blue in 1% aqueous solution at pH 1.0 for 5 min and alcian blue-Safranin at pH 1.0 for 30 min. MCs were generally associated with blood vessels in all reproductive organs. In the uterus, they were concentrated mainly in the close of the uterine gland and deep stroma in the endometrium. Higher MC numbers were observed by toluidine blue staining in the uterus, uterine cervix and uterine tubes on days 10 (corpus uterine: 4.7 ± 3.8 and cornu uterine: 4.9 ± 3.5) and 16 (corpus uterine: 5.9 ± 4.5 and cornu uterine: 5.4 ± 2.4) of the oestrous cycle compared with day 5 (p < 0.05). Mast cells were not observed in the follicles, the corpus luteum and the underside of the surface epithelium of the ovarian cortex, but were observed in the interstitial cortical stroma and the ovarian medulla. In the ovary, MC numbers were significantly higher on day 16 of the oestrous cycle (cortex: 3.4 ± 2.4 and medulla: 5.7 ± 4.5, p < 0.05). Safranin-positive connective tissue MCs were not observed in the uterine tube on any occasion. These results indicate oestrous cycle-related changes in the number and location of MCs in goat reproductive organs.  相似文献   

18.
本试验旨在研究不同脂肪水平饲粮对雌性水貂营养物质消化率、氮代谢及繁殖性能的影响。选择健康、体重相近的初产水貂120只,随机分成4组,每组3个重复,每个重复10只水貂。4组水貂分别饲喂蛋白质水平为45%,脂肪水平分别为10%(F10组)、14%(F14组)、18%(F18组)和22%(F22组)的试验饲粮。试验期为配种至产仔。结果表明:饲粮脂肪水平对水貂干物质和蛋白质消化率的影响不显著(P0.05),随着饲粮脂肪水平的升高,脂肪消化率呈上升趋势,其中F18、F22组显著高于F10组(P0.05)。饲粮脂肪水平对水貂日采食量和日食入氮量有极显著影响(P0.01),随着饲粮脂肪水平的升高,日采食量和日食入氮量均呈下降趋势。饲粮脂肪水平显著影响日粪氮和尿氮排出量及日氮沉积量、氮生物学效价(P0.05)。其中,F18组日粪氮和尿氮排出量最低,氮生物学效价最高。F14和F18组配种率、产仔率、窝产活仔数差异不显著(P0.05),但显著优于其他组(P0.05)。综合各项指标得出,在本试验条件下,水貂妊娠期饲粮蛋白质水平为45%时,饲粮的适宜脂肪水平为14%~18%,并且适宜饲粮脂肪水平能够提高水貂对蛋白质的利用率。  相似文献   

19.
Survival and movement are important demographic variables influencing the dynamics of large herbivores with implications for management and evolution of life‐history strategies. Management practices such as spatial confinement and harvest regulation attempt to control survival and movement for the sustainability of harvested deer populations, but a paucity of long‐term data exists on these management practices. We examined annual survival and site fidelity of free‐ranging white‐tailed deer (Odocoileus virginianus) over 10 years (1983–1992) to compare demographic parameters after spatial confinement (1993–2005). We used capture records (n = 174; 104 females, 70 males), marked deer recaptures (n = 42), and dead recoveries (n = 68) to estimate sex‐specific, age‐specific and time‐specific parameters. We found that annual female survival was 50% from 1983–1987 during a period of intense harvest, but increased to 93.7% after intense harvesting was eliminated. Prior to spatial confinement, annual survival of marked male deer averaged 36.7%–42.5%. After spatial confinement, annual survival increased on average for males (58%–99%) and females (77%–98%). Females showed high levels of site fidelity (>99%) prior to spatial confinement, whereas males showed much less site fidelity (≤4.5% for the 2 top‐ranking models). During spatial confinement, the semi‐impermeable fence effectively increased site fidelity of males (≥56%). These results stem from long‐term study (23 years) of a large herbivore experiencing changes to life‐history, resulting from changes in management that were applied to the population and aimed at altering population demographics, for sustainability of a harvestable population of deer.  相似文献   

20.
We investigated the reproductive biology of Knodus moenkhausii, an abundant small‐sized characin fish with broad occurrence in the Paraná River basin, Brazil. Specimens were collected monthly to determine fecundity, length at first maturity, reproductive period and spawning type. Gonads were macroscopically classified according to their form, size and texture in three different stages (immature, maturing or mature). Histological procedures were conducted to confirm gonadal developmental stages, and it was possible to notice that maturing females actually presented atretic oocytes, and all males that were macroscopically classified as immature, maturing and mature actually presented abundant spermatozoa in their gonads. Because of these discrepancies, a reclassification of gonadal maturations stages was needed after histological analysis, reinforcing its importance to studies on the reproduction of small characins. Reproduction occurred throughout the year though with two peaks. The length of the smallest mature individuals was 13 mm SL for males and 24 mm SL for females. Despite presenting relatively small batch fecundity, some life history traits such as early reproduction, multiple spawning throughout the year, in association with known opportunistic feeding habits, explain the high abundance of this species in locations where it occurs.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号