Mobility of the forearm skeleton in the Asiatic black (Ursus thibetanus), brown (U. arctos) and polar (U. maritimus) bears

In several primates and carnivores, pronation/supination angles of the forearm skeleton were examined, and it is thought that a larger angle is useful to acquire dexterous behaviors in feeding and/or life style, including climbing. In this study, the pronation/supination angles in Asiatic black, brown and polar bears were nondestructively examined. These specimens were classified as adult or non-adult. Three or four carcasses of each group of Asiatic black and brown bears were used for CT analysis, whereas only one adult polar bear was used. The forearms were positioned within the gantry of a CT scanner in both maximally supinated and pronated states. Extracted cross-sectional CT images of two positions were superimposed by overlapping the outlines of each ulna. The centroids of the radii were detected, and then the centroid of each radius and the midpoint of a line which connects between both ends of the surface of each radius facing the ulna, were connected by lines to measure the angle of rotation as an index of pronation/supination. In adult brown and polar bears, the angles were smaller as compared with the other groups (Asiatic black and non-adult brown bears). Asiatic black and non-adult brown bears can climb trees, whereas adult brown bears and polar bears cannot. This suggests that the pronation/supination angle is related to arboreal activity in Ursidae.

Histological features of the vomeronasal organ in the giraffe, Giraffa camelopardalis

The vomeronasal organ (VNO) that preferentially detects species-specific substances is diverse among animal species, and its morphological properties seem to reflect the ecological features of animals. This histological study of two female reticulated giraffes (Giraffa camelopardalis reticulata) found that the VNO is developed in giraffes. The lateral and medial regions of the vomeronasal lumen were covered with sensory and nonsensory epithelia, respectively. The vomeronasal glands were positive for periodic acid-Schiff and alcian blue (pH 2.5) stains. The VNO comprises several large veins like others in the order Cetartiodactyla, suggesting that these veins function in a pumping mechanism in this order. In addition, numerous thin-walled vessels located immediately beneath the epithelia covering the lumen entirely surrounded the vomeronasal lumen. This sponge-like structure might function as a specific secondary pump in giraffes.

Accessory corpora lutea formation in pregnant Hokkaido sika deer (Cervus nippon yesoensis) investigated by examination of ovarian dynamics and steroid hormone concentrations

Generally, sika deer conceive a single fetus, but approximately 80% of pregnant females have two corpora lutea (CLs). The function of the accessory CL (ACL) is unknown; moreover, the process of ACL formation is unclear, and understanding this is necessary to know its role. To elucidate the process of ACL formation, the ovarian dynamics of six adult Hokkaido sika deer females were examined ultrasonographically together with peripheral estradiol-17β and progesterone concentrations. ACLs formed in three females that conceived at the first estrus of the breeding season, but not in those females that conceived at the second estrus. After copulation, postconception ovulation of the dominant follicle of the first wave is induced by an increase in estradiol-17β, which leads to formation of an ACL. A relatively low concentration of progesterone after the first estrus of the breeding season is considered to be responsible for the increase in estradiol-17β after copulation.

The effects of frequent electroejaculation on the semen characteristics of a captive Siberian tiger (Panthera tigris altaica)

Artificial insemination (AI) can help to avoid inbreeding and genetic degeneration for sustaining genetically healthy populations of endangered species in captivity. Collection of a sufficient quantity of viable sperm is an essential first step in the AI process. In the present study, we examined the effects of frequent electroejaculation on semen characteristics in a Siberian tiger. We collected semen in all 17 trials during 6 breeding seasons (6 years). The mean number of sperm and the percentage of motile sperm were 294.3 ± 250.2×10⁶/ejaculate and 82.4 ± 11.4%, respectively. The number of motile sperm tended to increase during frequent electroejaculation in the same breeding season. Semen collection by electroejaculation can be performed effectively up to the fourth sequential ejaculate, which contained the most sperm in the study. In conclusion, frequent collection of sperm by electroejaculation from tigers may be effective for collection of a large number of motile sperm.

Surveillance for an outbreak of Encephalitozoon cuniculi infection in rabbits housed at a zoo and biosecurity countermeasures

An outbreak of encephalitozoonosis occurred in a rabbit colony at a zoo in Japan. Throughout the two years after the onset, all 42 rabbits were investigated clinically, pathologically and serologically for prevention and control of the disease. Eleven rabbits (11/42, 26.2%) showed clinical symptoms. Of 38 rabbits examined to detect specific antibodies against Encephalitozoon cuniculi, 71.1% (n=27) were found seropositive; 20 out of 30 clinically healthy rabbits (except for 8 clinical cases) were seropositive. The infection rate was 76.2% (32/42), including 5 pathologically diagnosed cases. The results of serological survey revealed that asymptomatic infection was widespread, even among clinically healthy rabbits. However, encephalitozoonosis was not found by pathological examination in any other species of animals kept in the same area within the zoo. Isolation and elimination of the rabbits with suspected infection based on the results of serological examination were carried out immediately; however, encephalitozoonosis continued to occur sporadically. Therefore, all the remaining rabbits were finally slaughtered. Then, the facility was closed, and all the equipment was disinfected. After a two-month interval, founder rabbits were introduced from encephalitozoonosis-free rabbitries for new colony formation. Since then, encephalitozoonosis has not been seen in any animals at the zoo. In this study, biosecurity countermeasures including staff education, epidemiological surveillance and application of an "all-out and all-in" system for rabbit colony establishment based on serological examination were successfully accomplished with regard to animal hygiene and public health for the eradication of E. cuniculi.

Metabolic alkalosis due to feeding chicks in breeding Adélie penguins Pygoscelis adeliae under natural conditions

Prolonged abnormal vomiting causes metabolic alkalosis. Many seabirds are known to feed their chicks by regurgitation. We hypothesized that metabolic alkalosis occurs in seabirds even under natural conditions during the breeding season. Adélie penguins Pygoscelis adeliae feed their chicks by regurgitating food for 50-60 d until the chicks fledge. In this study, the concentrations of Cl(-), HCO(3)(-), Na+, K+, pH, and PCO2 in the blood of breeding Adélie penguins were measured throughout the chick-rearing season. The pH of penguin venous blood shifted from 7.54 in the guarding period to 7.47 in the crèche period. Decreasing Cl(-) and increasing HCO(3)(-) blood concentrations in parents were associated with increasing mass of their brood in the guarding period, the early phase of the rearing season, indicating that regurgitating to feed chicks causes loss of gastric acid and results in relative metabolic alkalosis. The inverse trend was observed during the crèche period, the latter phase of the rearing season, when parents spent more time at sea and have fewer opportunities for gastric acid loss. This was assumed to be the recovery phase. These results indicate that regurgitation might cause metabolic alkalosis in breeding Adélie penguins. To our knowledge, this is the first report to indicate that seabirds exhibit metabolic alkalosis due to regurgitation to feed chicks under natural conditions.

Adenosquamous carcinoma with cilium formation, mucin production and keratinization in the nasal cavity of a red fox (Vulpes vulpes schrencki)

A diagnosis of adenosquamous carcinoma was made in an 11-year-old red fox. The animal showed emaciation and purulent nasal discharge. Necropsy revealed diffuse thickening of the nasal mucosa and tumours on the soft palate, and there was an oronasal fistula contiguous with the tumours. The nasal and oral lesions were composed of adenocarcinomatous cells and squamous cells, the latter predominating in the oral lesions. The marrow of the palatine bone also contained neoplastic tissue, which consisted of cysts and keratin masses surrounded by well-differentiated squamous cells. Although inconspicuous in the oral cavity and marrow, ciliated cells with or without mucin were observed in the adenocarcinomatous and cystic elements. Neoplastic basal cells and less-differentiated adenocarcinoma cells, which were identifiable by immunolabelling for cytokeratin 5 (CK5) and CK18, were considered to be pluripotential. These cells, which lined tubular structures, were distinct from intermediate cells in mucoepidermoid carcinoma, which can differentiate into squamous and mucin-producing cells but have a nondescript appearance.

Prevalence of antibody to hepatitis E virus among wild sika deer, Cervus nippon, in Japan

We examined 976 sika deer serum samples, 159 liver tissue samples and 88 stool samples collected from 16 prefectures in Japan, and performed ELISA and RT-PCR assays to detect antibodies to HEV and HEV RNA, respectively. Although 25 (2.6%) of 976 samples were positive for anti-HEV IgG, the antibody titers were very low. The OD values ranged between 0.018 and 0.486, forming a single distribution rather than a bimodal distribution, suggesting that the antibody detected in this study was not induced by HEV infection, or that deer have low sensitivity to HEV. HEV RNA was not detected in these samples, also suggesting that deer may not play a role as an HEV reservoir.

Malignant melanoma of the eyelid in a red squirrel (Sciurus vulgaris orientis)

A 6-year-old male red squirrel (Sciurus vulgaris orientis) developed bilateral tumors of upper and lower eyelids. The tumors in the left lid recurred despite surgical removal. Necropsy revealed metastasis to the lung. The neoplastic cells were epithelioid and highly pleomorphic, and only a few cells contained melanin granules. Occasionally melanoma cells were immunoreactive for S100, neuron-specific enolase and vimentin, and a small number of cells for cytokeratin. Ultrastructurally, the presence of premelanosomes was confirmed in the cytoplasm. Possible presence of cytokeratin-positive neoplastic melanocytes should be taken into account when differentiating a nonpigmented epithelioid melanoma from other tumors such as anaplastic carcinomas.

Isolation of Encephalitozoon cuniculi using primary tissue culture techniques from a rabbit in a colony showing encephalitozoonosis

Encephalitozoon spores were isolated in a primary tissue culture of the kidneys from an encephalitozoonosis-suspected rabbit in a municipal zoo in Hokkaido. The isolated spores were morphologically characteristic of microsporidial ones in chromotrope stain, and proven to be E. cuniculi by a polymerase chain reaction (PCR) with a species-specific primer set and by direct DNA sequencing of the PCR products.

Intestinal adenocarcinoma with neuroendocrine cells in a clouded leopard (Neofelis nebulosa)

Adenocarcinoma of the small intestine was found in a 6-year-old clouded leopard. This tumour was characterized by the presence of goblet and neuroendocrine cells. The latter were labelled positively for either serotonin, somatostatin, neurotensin, gastrin or secretin. These neuroendocrine cells were reduced in number in most of the metastatic lesions, including those of the mesentery, diaphragmatic pleura, lungs, liver and heart, and squamous metaplasia was detected in some metastatic sites.

Alveolar hydatidosis in a gorilla and a ring-tailed lemur in Japan

Alveolar hydatidosis by Echinococcus multilocularis (Em) infection occurred on a 22-year-old (approx.) male gorilla (Gorilla gorilla) and a 4-year-old female ring-tailed lemur (Lemur catta) in a zoo, in Hokkaido, Japan. Case 1: The gorilla presented neurologic signs in course of nine months and died. Pathologically, alveolar hydatid lesions were found in the liver, the liver-associated lymph nodes, the cerebrum, and the lungs. A protoscolex was found only in one hepatic cyst. Case 2: In the lemur, large masses of hydatide cysts were found on the liver and at the lung-associated lymph nodes. Cysts contained numerous calcareous corpuscles and protoscolices. The lemur appears a favorable intermediate-host for Em. The identification of Em in both cases were confirmed by PCR.

Molecular phylogenetic status of the iriomote cat Felis iriomotensis, inferred from mitochondrial DNA sequence analysis

To investigate the molecular phylogenetic status of the Iriomote cat Felis iriomotensis, partial sequences of the mitochondrial 12S rRNA gene (373 bases) and the cytochrome b gene (402 bases) were determined by using the polymerase chain reaction-product direct sequencing technique and then compared with those of seven other feline species. Six Iriomote cats examined in this study showed no intraspecific variation for both genes. The sequence comparisons and the molecular phylogenetic trees indicated that the Iriomote cat is very closely related to the leopard cat Felis bengalensis, which is a widespread species throughout southern and eastern Asia, and that it is reasonable for these two felines to be classified to the same genus. Based on sequence data, the Iriomote cat was estimated to have diverged from the leopard cat arround or less than 0.2 million years ago, and this concurs with the previously reported geological isolation date of the Ryukyu Arc from the Chinese continent. Our results suggest that the geographic barrier has led the fixation of some unique morphological characters into the Iriomote cat population while both the Iriomote cat and the leopard cat still retain very close genetic characters.