Comparative studies on lipid analysis and ultrastructure in porcine and southern minke whale (Balaenoptera bonaerensis) oocytes

The present study was conducted to clarify the difference in the color of the cytoplasm in immature follicular oocytes from prepubertal and adult minke whales. The four lipid contents (triglyceride, total cholesterol, phospholipids and non-esterified fatty acids) in vitrified immature oocytes from prepubertal and adult minke whales, and also in fresh and vitrified immature porcine oocytes, were measured. The lipid contents in vitrified-warmed minke whale oocytes were similarly high compared with those in vitrified-warmed porcine oocytes. In particular, the total cholesterol and phospholipid contents in the vitrified immature oocytes from prepubertal and adult minke whales were significantly (P<0.05) higher than those from prepubertal pigs. Furthermore, the distribution of lipid droplets in fresh and vitrified immature oocytes was observed in transmission electron microscopy. Lipid droplets in the prepubertal minke whale oocytes were distributed throughout the cytoplasm. In contrast, adult minke whales had larger lipid droplets which were distributed mainly in the central portion of the cytoplasm. The lipid droplets of immature oocytes from prepubertal pigs were larger than those in minke whale oocytes. These results indicated that the difference in the distribution of the cytoplasmic lipid droplets may result in the difference in the color tone of both prepubertal and adult whale oocyte cytoplasm.     

Attempt at intracytoplasmic sperm injection of in vitro matured oocytes in common minke whales (Balaenoptera acutorostrata) captured during the Kushiro Coast Survey

The present study was conducted during the Kushiro Coast Survey in an attempt to produce common minke whale embryos. In Experiment 1, we attempted to determine the appropriate culture duration (30 or 40 h) for in vitro maturation (IVM) of immature oocytes using the Well of the Well method. In Experiment 2, and intracytoplasmic sperm injection (ICSI) was applied to matured oocytes from prepubertal and adult common minke whales after IVM culture (40 or 48 h), and then their embryonic development was assessed. In Experiment 1, the maturation rate of oocytes cultured for 40 h (30.4%) was significantly higher than that of oocytes cultured for 30 h (6.8%; P<0.01). In Experiment 2, a total of 35 and 46 immature oocytes derived from adult (n=2) and prepubertal (n=6) minke whales, respectively, were cultured for 40 or 48 h. The maturation rate in the oocytes from the adult whales (34.2%) tended to be higher than that of the oocytes from the prepubertal whales (19.6%), but there was no significant difference. Following ICSI, 3 out of the 10 inseminated and cultured oocytes from the adult whales cleaved (2-, 8-, and 16-cell stages); all of these oocytes had been matured for 40 in culture. However, these oocytes did not develop to further stages. Only one of the 6 oocytes derived from the prepubertal whales, IVM cultured for 40 h and inseminated, developed to the 4-cell stage. The present results indicate that a 40 h IVM culture produces significantly higher rates of in vitro maturation than a 30 h IVM culture for common minke whale oocytes. Following ICSI, some oocytes cleaved to the 16-cell stage, but no further development was observed.     

Pathological and serological evidence of Brucella-infection in baleen whales (Mysticeti) in the western North Pacific

Abnormal testes and uterus were observed in 13 males (33%) and one female (3%) out of 40 common minke whales (Balaenoptera acutorostrata) in the western North Pacific. Similar lesions were found in testis and ovary, respectively, in one male (2%) and female (2%) out of 43 Bryde's whales (Balaenoptera edeni) in the western North Pacific. Grossly, granular lesions with caseation and calcification were main pathological signs, and they were restricted to reproductive organs of mature whales. Chronic purulent or granulomatous orchitis was observed by microscopic analysis. Antibodies to Brucella species were detected in the serum samples of 15/40 (38%) of common minke whales and 4/43 (9%) of Bryde's whales. Neither pathological nor serological change was found in the examined sperm whales (Physeter macrocephalus) in the western North Pacific and Antarctic minke whales (Balaenoptera bonaerensis). These results strongly suggest that Brucella infection was involved in two species of baleen whales (Mysticeti) in the North Pacific.     

Cell-specific Distribution of Oestrogen Receptor-alpha in the Bovine Ovary

In this study, the expression of estrogen receptor alpha (ERα) in the bovine ovary is described. ERα was visualized by immunohistochemistry on paraffin sections of ovaries obtained from 11 non‐pregnant and 2 pregnant animals. In general, ERα was not observed in cells of primordial, primary and secondary follicles, whereas weak expression was noticed in cells of healthy and arteric tertiary follicles. In corpora lutea cells the expression of ERα was obvious. Intermediate to high ERα expression was present in thecal cells and in cells of the superficial and deep stroma, tunica albuginea and surface epithelium. Furthermore, the expression of ERα in stroma and tunica albuginea cells was in general, highest in cows with the lowest plasma progesterone levels, and lowest in cows with the highest plasma progesterone levels. Remarkably, the ERα expression in pregnant cows was in general, lower than in non‐pregnant cows with similar plasma progesterone levels. The relatively high expression of ERα in thecal and stromal cells in comparison with that in follicle cells suggests an indirect effect of estrogen on the follicular development. However, the exact function of ERα in the bovine ovary together with the cycle‐dependent variations in ERα expression remain to be elucidated.     

Relationship between ovarian weight and follicular population in heifers

The size of the ovary varies substantially among cattle. This variation may influence the potential of the ovary to produce follicles. In the present study, we examined whether a relationship exists between the weight of the ovary and the number of antral follicles >or=1 mm. Paired ovaries were obtained from Holstein x Japanese Black F1 heifers. Follicles were classified into three size categories (small: 1.0-<5.0 mm, medium: 5.0-<8.5 mm and large: >or=8.5 mm), and the number of follicles in each category was recorded. Large variations in the weight of ovaries and the number of follicles were observed among animals. Significant positive correlations (r>or=0.4, P<0.001) were found between the weight of intact ovaries and the number of follicles in all three categories for the ovary contralateral to CL (OCC) and in the small follicles for the ovary ipsilateral to CL (OIC). Significant positive correlations (r>0.4, P<0.0001) were also observed between the weight of ovaries devoid of CL and follicles and the number of small and medium follicles in both OIC and OCC, indicating that the correlation is not due to the increase in ovarian weight associated with the increase in follicular number. Paired ovaries contained a similar number of small and medium follicles, and significant positive correlations were observed between them (r>0.6, P<0.0001). There were significant positive correlations between the weight of OCC and the number of small and medium follicles in paired ovaries (r>0.4, P<0.0001). These results suggest that 1) the weight of an ovary reflects the potential of the ovary to produce antral follicles, and 2) a rough estimation of follicular population might be possible by using the weight of the ovary contralateral to CL in heifers.     

Follicle size-dependent changes in follicular fluid components and oocyte diameter in Antarctic minke whales (Balaenoptera bonaerensis)

The concentrations of various components of follicular fluid were compared among three groups of follicles (small, <5 mm; medium: 5-10 mm; large, >10 mm) with a control that consisted of the components of umbilical serum using seven pregnant Antarctic minke whales. Follicular oocytes recovered from the follicles were also used for measurement of oocyte diameter after removing the cumulus cells. The mean diameter of the ooplasm in the oocytes from the large follicles (143.2 microm) was significantly greater than those from the small (127.1 microm) and medium (131.7 microm) follicles, although there were no significant differences in diameter of the whole oocyte and thickness of the zona pellucida among the three follicular sizes. The osmolarity of the follicular fluid from the small follicles (363.3 mOsmol) was significantly lower than that of the medium follicles (388.9 mOsmol) and tended to be lower than that of large (381.9 mOsmol) follicles, respectively, both of which were similar to that of the umbilical serum (379.5 mOsmol). There was no significant difference in the concentrations of all components of the follicular fluid between the medium and large follicles. As compared with the values of the umbilical serum, the total-protein, glucose, albumin and chlorine concentrations of the follicular fluid from the medium and large follicles were significantly higher, and the total cholesterol and calcium concentrations were significantly lower. The concentrations of lactic acid (85.3-136.0 mg/dl) of the follicular fluid from the three groups of follicles were significantly lower than that of the umbilical serum (360.0 mg/dl). Among the follicles, the follicular fluid from the small follicles (136.0 mg/dl) contained a significantly higher concentration of lactic acid than that from the large follicles (85.3 mg/dl). The progesterone concentrations were not significantly different among the fluid from the three group of follicles and the umbilical serum: however, the estradiol 17-beta concentrations of the follicular fluid increased with the size of the follicle (14.3 and 34.6 ng/ml for small and large follicles, respectively). These results offer new information concerning whale reproductive physiology, especially for improvement of in vitro oocyte maturation and related technologies in whales.     

The effect of repeated follicular puncture on ovarian function in dairy heifers

Three dairy heifers were examined during three consecutive oestrous cycles (control period, CP). Subsequently, the animals were subjected to 4 and then 5 weeks of twice-weekly ovum pick-up (OPU) (FPP1 and FPP2, respectively) with a recovery period (RP) of two consecutive oestrous cycles between FPP1 and FPP2. After FPP2, the animals were slaughtered and the ovaries were macroscopically examined. Throughout, ovarian activity was monitored by transrectal ultrasonography and concentrations of plasma progesterone. During CP, all the heifers showed normal cyclicity. During FPPs, the heifers occasionally presented oestrous activity. Corpus luteum (CL)-like structures developed from punctured follicles with diameters and life-spans varying from smaller and shorter than those in the CP (P > 0.05) to equal to those in the CP. There was a tendency for a lower number of emerging and punctured follicles in the presence of a CL-like structure. Subsequently to FPP1, all heifers regained normal cyclicity. A thickening of the ovarian tunica albuginea and a slight hardening of the ovaries were found postmortem. In conclusion, dairy heifers can occasionally show cyclic activity and form CL-like structures during twice-weekly OPU. Further, OPU did not seem to cause any major negative effects on ovarian structure and subsequent ovarian function.     

卵巢大小及发育状况与牛腔前卵泡采集数量的关系

用简单机械分离法处理了 12 7枚成年牛卵巢。结果显示 ,在外观正常的卵巢中 ,腔前卵泡的采集数量与卵巢的大小成正相关关系 ,而有无黄体与腔前卵泡的采集数量无明显关系 ;卵巢上不同大小的可见卵泡的数量和分布与腔前卵泡的采集量有关。卵巢上可见卵泡分布均衡 ,大、中、小卵泡均有分布 ,小卵泡不过多以及无大卵泡 ,但中、小卵泡较多的 ,无论是否有黄体存在 ,均可获得较多腔前卵泡。而卵巢表面脂肪化、卵巢充血、有弥散性片状黄体及幼稚卵巢的 ,则腔前卵泡分离很少或几乎分离不到     

The Anatomy of the Male Genital System of the Beluga Whale, Delphinapterus leucas, with Special Reference to the Penis

The genital organs of four male adult beluga whales and one newborn animal were dissected and the main characteristics are described. As in other species of cetaceans, the testes and the greatest part of the penis are located inside the abdominal cavity. The penis has a sigmoid flexure and belongs to the fibroelastic type with a thick tunica albuginea and a small amount of vascular spaces in the erectile tissue. The prostate gland, found in other cetaceans, was not seen macroscopically, but only small prostate rudiments could be identified histologically. The os penis and the other accessory glands are absent as in other whales.     

Relationship between serum sex hormone concentrations and histology of seminiferous tubules of captured baleen whales in the Western North Pacific during the feeding season

The present study was conducted to obtain new information on relationships among serum testosterone (T), estradiol-17 beta (E(2)), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) concentrations and histology of seminiferous tubules in captured common minke and Bryde's whales during the feeding season. Blood samples and testes were collected from common minke (n=39 for blood samples, n=15 for testes) and Bryde's (n=14 for blood samples, n=7 for testes) whales captured from May 2001 to August 2001 in the Western North Pacific. Serum T concentrations, in 35.9% of the common minke and 57.1% of Bryde's whales, were below the detection limit (< 2.5 pg/ml). There were no significant differences in the serum concentrations of E(2), FSH, and LH among immature, mature common minke and Bryde's whales except that LH levels of immature Bryde's whales was higher than those of common minke whales. In most seminiferous tubules of mature whales, only a single-layer of spermatogonia was observed. However, spermatozoa were observed in seminiferous tubules in 2/13 of mature common minke and 4/4 of mature Bryde's whales with the low or undetectable T levels. These results indicate that the low serum T concentrations reflect the inactivity of spermatogenesis in both baleen whales, and that it is not possible to assess gonadal activity in either common minke or Bryde's whales using serum sex hormone concentrations during the feeding season.     

Ultrasonographic findings of an ovarian abscess in a cow

Ultrasonographic examination was carried out in a cow with an ovarian abscess. Real time ultrasound scanning using a 7.5 MHz linear probe per rectum revealed an active left ovary with follicles of up to 11 mm in diameter and an enlarged right ovary measuring 6 x 6 cm, with a mass of 4 x 3 cm. The mass had varied echotexture, a thick hyperechoic boundary and a hypoechoic centre with echoic foci. It was tentatively diagnosed as an ovarian tumour or abscess. After ovariectomy, grossly the right ovary measured 6 x 6 x 5 cm and on cutting cheesy pus oozed out. The abscess was completely localised within the ovary, 4 cm in diameter and encapsulated thickly. On bacteriological examination Staphylococcus spp. was isolated. This is a rare case of ovarian abscess.     

Structure and Steroidogenesis of the Placenta in the Antarctic Minke Whale (Balaenoptera bonaerensis)

There are few reports describing the structure and function of the whale placenta with the advance of pregnancy. In this study, therefore, the placenta and nonpregnant uterus of the Antarctic minke whale were observed morphologically and immunohistochemically. Placentas and nonpregnant uteri were collected from the 15th, 16th and 18th Japanese Whale Research Programme with Special Permit in the Antarctic (JARPA) and 1st JARPA II organized by the Institute of Cetacean Research in Tokyo, Japan. In the macro- and microscopic observations, the placenta of the Antarctic minke whale was a diffuse and epitheliochorial placenta. The chorion was interdigitated to the endometrium by primary, secondary and tertiary villi, which contained no specialized trophoblast cells such as binucleate cells, and the interdigitation became complicated with the progress of gestation. Furthermore, fetal and maternal blood vessels indented deeply into the trophoblast cells and endometrial epithelium respectively with fetal growth. The minke whale placenta showed a fold-like shape as opposed to a finger-like shape. In both nonpregnant and pregnant uteri, many uterine glands were distributed. The uterine glands in the superficial layer of the pregnant endometrium had a wide lumen and large epithelial cells as compared with those in the deep layer. On the other hand, in the nonpregnant endometrium, the uterine glands had a narrower lumen and smaller epithelial cells than in the pregnant endometrium. In immunohistochemical detection, immunoreactivity for P450scc was detected in most trophoblast cells, but not in nonpregnant uteri, suggesting that trophoblast epithelial cells synthesized and secreted the sex steroid hormones and/or their precursors to maintain the pregnancy in the Antarctic minke whale.     

The asymmetric distribution of ovarian functional structures in cattle

The results of continually repeated transrectal palpations, performed in 168 post partum periods, 383 estrous cycles and 178 early pregnancies, were used to describe and to discuss the left-right distribution of ovarian functional structures. In cycling as well as in pregnant cattle, anovulatory interestral follicles and estrous follicles or corpora lutea in the mean were all distributed at 41% and 59% on the left and right ovaries respectively. No signs were found indicating that the position of functional structures would be influenced by local interactions between follicles and corpora lutea. At least for cyclic ovarian activity, and in early pregnancy, the interrelationship observed between the locations of these structures could be put down to the normally increased activity of the right ovary. After delivery, the first follicles preferentially became discernible on the ovary opposite to the previously pregnant uterine horn. But, as from the 4th follicle p.p. onward, the distribution of new ovarian structures again agreed with the one of the ensuing reproductive stages. After calving, probably the position of new follicles is temporally influenced by direct signals from the uterine horns affected differently by pregnancy. Several observations indicate that the factors causing asymmetrical ovarian activity could exert a selective effect on the recruitment of the dominant and solitary interestral follicles from the pool of their minor and less differentiated precursors.     

The effect of ovarian status and follicular diameter on maturational ability of domestic cat oocytes

The objective of this study was to clarify the effect of ovarian status and follicular size on morphological normality and maturational ability of cat oocytes. Ovarian status was classified into inactive, follicular, luteal and prepubertal, and follicles were classified into three groups according to their diameter (400-800, 800-1200 and 1200-2000 μm). In each ovarian status, the number of follicles decreased but the percentage of morphologically normal oocytes increased with the growth of follicles (p<0.05). Only a single follicle that was 1200-2000 μm in diameter was observed in two of the five prepubertal cats. In follicles that were 800-1200 μm in diameter, the percentage of normal oocytes and maturation rate were higher in prepubertal cats than in mature cats (p<0.05). Oocyte diameter tended to increase with the growth of follicles. After oocytes were cultured individually in droplets of maturation medium, the oocyte maturation rate increased with the growth of follicles in each ovarian status (p<0.05). In conclusion, oocytes collected from larger follicles possess higher maturational ability in vitro in sexually mature cats. In prepubertal cats, a higher maturation rate can be obtained from oocytes derived from small follicles compared with in mature cats.     

Relationship between two morphological types of ovaries and their follicular microscopic population before puberty and their ensuing follicular development and ovulation rates at puberty in gilts

A population of ovarian follicles was studied in 32 gilts with two morphological types at four physiological stages. Left ovaries were serially sectioned (10 microns), and follicles (greater than .19 mm) were counted and measured by histological technique. In Exp. 1, prepuberal gilts that maintained the grape-type (GT) or other-type (OT) of ovaries at 140 and 160 d of age as determined by laparoscopy had their population of follicles studied at 165 d of age and compared with that on d 3 of the first puberal estrus in gilts that maintained the same ovarian type (GT or OT) at 140, 160 and 180 d of age. In Exp. 2, gilts that maintained the same ovarian types at 140, 160 and 180 d of age were compared at d 19 and 3 of the first and second puberal estrus, respectively. At 165 d of age, OT ovaries contained a greater number of classes 3 (.63 to 1.12 mm) and 4 (1.13 to 2.00 mm) nonatretic (less than 4 pycnotic bodies) follicles than GT (P less than .01), whereas at d 3 of the first puberal estrus, their mean number became comparable between the two ovarian types (P greater than .1) and similar to 165-d GT ovaries. At 165 d of age, atretic follicles formed 19.6% and 10.7% of the population of antral follicles in OT and GT ovaries (P less than .05) whereas at puberty 17.5% and 19.6% atresia was observed in the same two groups, respectively (P greater than .10).(ABSTRACT TRUNCATED AT 250 WORDS)     

Ovarian morphological conditions and the effect of injection of human chorionic gonadotropin on ovulation rates in prepuberal gilts with two morphologically different ovarian types

The purpose of this experiment was to determine the ovulation rate after treatment with human chorionic gonadotropin (hCG) in two groups of gilts characterized by different ovarian morphology: grape-type (GT; n = 11) and honeycomb-type (HT; n = 7). At 170 d of age (d 0), gilts were examined by laparoscopy and ovarian type was determined by the distribution of macroscopic follicles present on the ovarian surface. Five to ten minutes after surgery, each gilt received a single injection (i.m.) of 750 IU of hCG. At d 0, GT ovaries had a greater number of large follicles (greater than or equal to 6 mm) than HT ovaries (10.0 +/- .5 vs 2.6 +/- .3; P less than .05), whereas HT ovaries had more small follicles (1 to 3 mm; HT: 42.3 +/- .8 vs GT: 26.7 +/- .9; P less than .05) and total follicles (HT: 59.4 +/- 2.3 vs GT: 52.2 +/- 1.5; P less than .05), although numbers of medium follicles (4 to 5 mm) were similar (GT: 15.6 +/- .8 vs HT: 14.6 +/- 1.7; P greater than .10). Number of induced corpora lutea (CL) per ovary was greater (P less than .05) in gilts with GT ovaries (10.59 +/- 2.9 CL) than in gilts with HT ovaries (5.21 +/- .66 CL). Total weight of luteal tissue (LT) per ovary and serum progesterone concentrations 8 d after induction of ovulation were greater in GT gilts than in HT gilts (GT: 6.37 +/- 1.09 g vs HT: 3.31 +/- .49 g for LT, P less than .05; GT: 21.08 +/- 4.76 ng/ml vs HT: 13.40 +/- 2.05 ng/ml for progesterone, P less than .07).(ABSTRACT TRUNCATED AT 250 WORDS)     

双峰驼卵巢的组织结构

应用组织学方法对双峰驼卵巢的形态结构进行了显微与亚显微观察。结果显示 ,双峰驼卵巢表面被覆单层立方至单层扁平的生殖上皮 ,无排卵窝 ,上皮下为致密结缔组织白膜 ,卵巢实质由外周的皮质和中央的髓质构成。皮质中原始卵泡和初级卵胞数量稀少 ,其分布位置更靠近皮质中层 ,偶见同一卵泡内含 2个卵母细胞。体积大小和发育阶段不同的次级卵泡与三级卵泡闭锁时 ,所发生的形态变化不一致 ,可出现实心和囊状 2种闭锁卵泡。黄体中以粒性黄体细胞占优势 ,其细胞质中含大量脂质泡而呈海绵样。卵巢髓质中除含大量血管外 ,还见卵巢网分布     

Comparative histological study of the reproductive system of the female llama (Lama guanicoe glama). I. Ovary]

In the present study a cytological, histological and morphometrical comparison between the ovaries of the llama, the cow and the sheep is presented, at two phases of the ovarian cycle. There were found differences in the amount of primordial and primary follicles, the size of secondary follicles and follicular cells, and type and distribution of the connective tissue inside the stroma of the ovary. It would be necessary to study the fine structure of the ovary and the so-called "embryological remnants", for its permanent appearance in most (50%) of the ovaries.     

Description and Analysis of the use of Cold Harpoons in the Norwegian Minke Whale Hunt in the 1981,1982 and 1983 Hunting Seasons

Until 1984, cold harpoons, i.e. harpoons with no detonating device, were used to hunt minke whales in Norway. To investigate the effectiveness of such harpoons and compare them with alternatives, data on kills using cold harpoons were collected as part of a project dealing with alternative killing techniques for whales. Data on 353 whale kills were collected in 1981–83. The criteria used to determine the time of death were cessation of flipper movement, that the mandible relaxed, or that the whale hung immobile from the harpoon line. These criteria do not take into account any movements caused by spinal reflexes. About 17% of the animals died instantaneously (≤10 s). The median survival time was 570 s. Animals died most rapidly if hit in the brain, heart or major blood vessels. If only the lungs were injured, minke whales died less rapidly than terrestrial mammals. For whales that did not die immediately, shooting range, animal size and the angle of the shot all influenced the time to death. The efficiency of cold harpoons could be improved, but their use was no longer considered acceptable, and they were replaced by harpoons with penthrite grenades in 1984.