Evolutionary comparison of energy economy between finnish and Japanese raccoon dogs

• 1.1. The paper describes evolutionary differences in energetics between the raccoon dogs originated from islands (Japan) and mainlands (eastern Asia).
• 2.2. The Japanese raccoon dog is specialized to live in a temperate marine climate; it has a stomach of small volume, thin fur coat with low insulation, specialized diet and a poor ability to alter its body energy reserves seasonally.
• 3.3. The raccoon dog living in mainland is more generalized, and thus also well-adapted to survive extreme climate of northern latitudes.
• 4.4. The results confirm the previous conclusions made from chromosomal analyses that the Japanese raccoon dog has evolved from the mainland form.

     

Relationship between seasonal energy economy and thyroid activity in farm-raised raccoon dogs

1. The levels of thyroid hormones (T3, T4), total lipids and urea in blood serum of adult farmed raccoon dogs (Nyctereutes procyonoides Gray 1834) were monitored year-round, and compared with seasonal changes in body weight and feed consumption during intense, maintenance and restricted fasting feeding. 2. Thyroid hormone levels tended to be low during winter whereas during the rest of the year no marked seasonal differences were observed. That thyroid hormone levels were influenced by altering feed intake suggests the hypothesis that the winter hypothyroidism observed was a result of a decreased level of voluntary feed intake. 3. The colder the temperature was during winter, the less the animals consumed the feed supplied. 4. Neither season nor feed intake level affected serum levels of total lipids or urea. 5. Marked seasonal changes in body weight of the animals were found. From maximum values occurring in early winter their body weight generally dropped about 30% reaching the minimum values in mid-summer. This marked seasonal change was mainly the result of changes in subcutaneous fat reserves.     

Heat loss of farmed raccoon dogs and blue foxes as evaluated by infrared thermography and body cooling

Infrared thermographs showed that heat loss of the raccoon dog (Nyctereutes procyonoides Gray 1834) is greatest from the chest, the head, the abdomen and the feet. The blue fox (Alopex lagopus) seems to be somewhat better insulated. Mass-0.75 specific heat transfer coefficients (W/kg 0.75 per degrees C) in both species were similar. The wooden nest was able to decrease it significantly. The results support the conclusion that heat loss, and thus the energy costs, of studied species could be reduced by providing them with either a winter nest or a rest-shelf in the cage.     

Reproductive potential of Echinococcus multilocularis in experimentally infected foxes, dogs, raccoon dogs and cats

A total of 15 red foxes, 15 raccoon dogs, 15 domestic dogs and 15 domestic cats were each infected with 20,000 protoscolices of Echinococcus multilocularis. At 35, 63, and 90 days post inoculation (dpi), five animals from each group were necropsied and the worm burdens determined. The highest worm burdens in foxes (mean of 16,792) and raccoon dogs (mean of 7930) were found at 35 dpi. These declined to a mean of just 331 worms in foxes and 3213 worms in raccoon dogs by day 63 with a further decline to 134 worms in foxes and 67 worms in raccoon dogs by day 90. In dogs, there was no significant difference between worm burdens recovered at days 35 (mean of 2466) and day 90 (mean of 1563), although reduced numbers were recovered on day 63 (mean of 899). In cats, worms were found in four animals 35 dpi (mean of 642), in three at 63 dpi (mean of 28) and in two at 90 dpi (mean of 57). Faecal egg counts were determined at 3 day intervals from 25 dpi. A mathematical model of egg excretion dynamics suggested that the mean biotic potential per infected animal was high in foxes (346,473 eggs); raccoon dogs (335,361 eggs) and dogs (279,910 eggs) but very low for cats (573 eggs). It also indicated that approximately 114, 42 and 27 eggs per worm were excreted in the faeces of dogs, raccoon dogs and foxes, respectively. The fecundity of worms in cats was low with an average of less than one egg per worm. The peak levels of coproantigen were detected earlier in foxes and raccoon dogs than in dogs. Eggs recovered from foxes, raccoon dogs and dogs resulted in massive infections in experimental mice. However, metacestodes did not develop from eggs originating from infected cats. It is concluded that foxes, raccoon dogs and dogs are good hosts of E. multilocularis. In contrast, the low worm establishment, the very few excreted eggs and the lack of infectivity of eggs strongly indicate that cats play an insignificant role in parasite transmission.     

Prevalence of Toxoplasma gondii infection diagnosed by PCR in farmed red foxes, arctic foxes and raccoon dogs

The aim of this study was to compare Toxoplasma gondii infection in three canid species: red fox Vulpes vulpes, arctic fox Vulpes lagopus and raccoon dog Nyctereutesprocyonoides kept at the same farm. Anal swabs were taken from 24 adult and 10 juvenile red foxes, 12 adult arctic foxes, three adult and seven juvenile raccoon dogs. Additionally, muscle samples were taken from 10 juvenile red foxes. PCR was used to detect T. gondii DNA. T. gondii infection was not detected in any of the arctic foxes; 60% ofraccoon dogs were infected; the prevalence of the parasite in material from red fox swabs was intermediate between the prevalence observed in arctic foxes and raccoon dogs. It is possible that susceptibility and immune response to the parasite differ between the three investigated canid species. T. gondii DNA was detected in muscle tissue of five young foxes. The results of this study suggest that T. gondii infection is not rare in farmed canids.     

Voluntary regulation of energy balance in farmed raccoon dogs

1. Seasonal changes in body mass and voluntary feed intake were studied in juvenile raccoon dogs (Nyctereutes procyonoides, Gray 1834) under farm conditions. 2. The body weight maximum was achieved in mid-November. Thereafter, body weight gradually declined towards summer. This pattern was closely connected to voluntary regulation of feed consumption. During autumn, appetite of the animals was good enhancing gradual deposition of excessive fat reserves. 3. Excessive adiposity itself, together with factors like shortening daylength and decreasing air temperature, seemed to play as a trigger for starting of winter rest. 4. The results support the endogenic nature of energy balance regulation.     

从健康狐狸、貉粪中检出犬冠状病毒的两种基因型

取某养殖场健康狐狸 (6 1份 )、貉 (2 4份 )粪样 ,用套式PCR(RT-nPCR)方法检测犬冠状病毒 (CCV)并进行基因型鉴定。结果显示 :狐狸粪样中有 4 3份 (70 . 5 % )为CCVⅡ型阳性 ,2 9份 (47. 5 % )为CCVⅠ型阳性 ,两型混合感染2 5份 ,占 4 1 0 % ,两型总感染率为 77 .0 %。 2 4份貉粪样中 ,2 2份为CCVⅡ型阳性 (91 .7% ) ,其中 16份为CCVⅠ型、Ⅱ型混合感染 (6 6 . 7% )。分别取狐狸和貉粪样中CCVⅠ、Ⅱ型阳性PCR产物各 2份 (共 8份 )进行测序 ,均与CCV的M基因序列相符 ,证实PCR结果非假阳性。序列及系统进化分析表明 ,CCVⅠ型与源于意大利腹泻犬的CCVⅠ型 (AF5 0 2 5 83)同源性最高 (96 . 7%～ 98. 1% ) ;CCVⅠ、Ⅱ两种基因型同源性为 88. 3%～ 89. 7% ,在进化树中处于两个大的分支上 ;同为CCVⅡ型 ,狐狸源与貉源序列也存在多个位点差异。首次在貉粪中检出CCV ,证实在健康狐狸、貉群体中存在CCV流行 ,且CCVⅠ、Ⅱ型并存。     

Helminths of red foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) in Lithuania

Red foxes and raccoon dogs are hosts for a wide range of parasites including important zoonotic helminths. The raccoon dog has recently invaded into Europe from the east. The contribution of this exotic species to the epidemiology of parasitic diseases, particularly parasitic zoonoses is unknown. The helminth fauna and the abundance of helminth infections were determined in 310 carcasses of hunted red foxes and 99 of raccoon dogs from Lithuania. Both species were highly infected with Alaria alata (94·8% and 96·5% respectively) and Trichinella spp. (46·6% and 29·3%). High and significantly different prevalences in foxes and raccoon dogs were found for Eucoleus aerophilus (97·1% and 30·2% respectively), Crenosoma vulpis (53·8% and 15·1%), Capillaria plica (93·3% and 11·3%), C. putorii (29·4% and 51·5%), Toxocara canis (40·5% and 17·6%) and Uncinaria stenocephala (76·9% and 98·8%). The prevalences of the rodent-transmitted cestodes Echinococcus multilocularis, Taenia polyacantha, T. crassiceps and Mesocestoides spp. were significantly higher in foxes than in raccoon dogs. The abundances of E. multilocularis, Mesocestoides, Taenia, C. plica and E. aerophilus were higher in foxes than those in raccoon dogs. A. alata, U. stenocephala, C. putorii and Echinostomatidae had higher abundances in raccoon dogs. The difference in prevalence and abundance of helminths in both animals may reflect differences in host ecology and susceptibility. The data are consistent with red foxes playing a more important role than raccoon dogs in the transmission of E. multilocularis in Lithuania.     

Asymmetrical intraguild interactions with coyotes,red foxes,and domestic dogs may contribute to competitive exclusion of declining gray foxes

Species coexistence is governed by availability of resources and intraguild interactions including strategies to reduce ecological overlap. Gray foxes are dietary generalist mesopredators expected to benefit from anthropogenic disturbance, but populations have declined across the midwestern USA, including severe local extirpation rates coinciding with high coyote and domestic dog occurrence and low red fox occurrence. We used data from a large‐scale camera trap survey in southern Illinois, USA to quantify intraguild spatial and temporal interactions among the canid guild including domestic dogs. We used a two‐species co‐occurrence model to make pairwise assessments of conditional occupancy and detection rates. We also estimated temporal activity overlap among species and fit a fixed‐effects hierarchical community occupancy model with the four canid species. We partitioned the posterior distributions to compare gray fox occupancy probabilities conditional on estimated state of combinations of other species to assess support for hypothesized interactions. We found no evidence of broadscale avoidance among native canids and conclude that spatial and temporal segregation were limited by ubiquitous human disturbance. Mean guild richness was two canid species at a site and gray fox occupancy was greater when any combination of sympatric canids was also present, setting the stage for competitive exclusion over time. Domestic dogs may amplify competitive interactions by increasing canid guild size to the detriment of gray foxes. Our results suggest that while human activities can benefit some mesopredators, other species such as gray foxes may serve as bellwethers for habitat degradation with trophic downgrading and continued anthropogenic homogenization.     

Hepatic biotransformation in farmed blue fox and raccoon dog

In farmed raccoon dogs and blue foxes, the hepatic content of cytochrome P-450 and the activity of polysubstrate mono-oxygenase with benzo(a)pyrene and 7-ethoxycoumarin as substrates, as well as activity of UDP glucuronosyltransferase were of the same order of magnitude as those in the laboratory rat. The amount of reduced glutathione tended to be higher in canids. There existed differences in the biotransformation activities between raccoon dogs from different farms. These cannot, however, be systematically related to the quality of food, body composition and succinate dehydrogenase activity.     

Fragile sites, telomeric DNA sequences, B chromosomes, and DNA content in raccoon dogs, Nyctereutes procyonoides, with comparative notes on foxes, coyote, wolf, and raccoon

Earlier studies of the genus Nyctereutes disclosed two subspecies of differing chromosome numbers accompanied by B chromosomes. To further define the relationship of these subspecies to each other, and to other carnivores, and to learn more about the structure and function of their chromosomes, we characterized and compared the genomes in terms of DNA content by flow cytometry, fragile sites induced by aphidicolin, and telomere sequences using biotinylated DNA probes detected with fluorescence. We also characterized the B chromosomes of these two subspecies.     

Seroprevalence of antibodies to Neospora caninum in dogs and raccoon dogs in Korea

Neospora caninum is an important cause of abortion in cattle, and dogs are its only known definitive host. Its seroprevalence among domestic urban and rural dogs and feral raccoon dogs (Nyctereutes procyonoides koreensis) in Korea was studied by indirect fluorescent antibody test (IFAT) and by the neospora agglutination test (NAT), respectively. Antibodies to N. caninum were found in 8.3% of urban dogs and in 21.6% of dogs at dairy farms. Antibody titers ranged from 1:50 to 1:400. Antibodies to N. caninum were found in six (23%) of 26 raccoon dogs. However, the potential role of raccoon dogs as a source of horizontal transmission of bovine neosporosis needs further investigation. The results of this study suggest that there is a close relationship between N. caninum infection among dairy farm dogs and cattle in Korea. This study reports for the first time upon the seroprevalence of N. caninum infection in raccoon dogs in Korea.     

Experimental infection of Dirofilaria immitis in raccoon dogs

Canine heartworm (Dirofilaria immitis) is a nematode that naturally parasitizes in the pulmonary arteries and the right ventricle of domestic dogs (Canis familiaris) as final hosts. Japanese raccoon dogs (Nyctereutes procyonoides viverrinus) also are known to be susceptible to infection by the parasite. However, prevalence of this infection among free-ranging raccoon dogs is low and so is the worm burden. To examine the susceptibility of the raccoon dog to D. immitis infection, 3 raccoon dogs and 2 beagles were inoculated 4 times with 25 third-stage larvae (L3s) of D. immitis at 3-wk intervals. Worms were recovered from 2 raccoon dogs and both domestic dogs. The average percentage of recovery (2.3%) of the raccoon dogs was almost 10 times lower (24.5%) than that of the domestic dogs, but there was no significant difference in the body length of worms recovered from 2 types of hosts. To examine microfilaremia, 2 raccoon dogs were infected with 100 L3s. Microfilaremia was observed for 180 days postinoculation (PI) but disappeared at about 300 days PI. The raccoon dog was mildly susceptible to infection with D. immitis, but surviving worms developed and matured normally.     

Diet of raccoon dogs in summer in the Finnish archipelago

The diet of raccoon dogs in summer was examined in the Finnish archipelago and compared with their diet on the mainland. Faeces were collected from latrines in the outer archipelago and the inhabited islands in May-July 1998 and 1999. Remains of waterfowl, especially those of female cider, occurred frequently in the faeces of raccoon dogs on the uninhabited islands, but less frequently on the inhabited islands and only occasionally on the mainland. Since many female eider died of disease during the summer in 1998 and 1999. and white-tailed eagles arc known to prey on brooding eider, it is probable that raccoon dogs did not themselves kill all the eider they consumed. Even if they did, they would only take a few percent of female eider population each year. It is thus improbable that raccoon dogs affect the size of the eider population in the Finnish archipelago. Frogs, reptiles, shrews and carrion occurred frequently in the diet on the mainland, but only occasionally in the outer archipelago. It is possible that raccoon dogs have decimated frog populations on small islands, as they are easy prey and occur frequently in the diet of raccoon dogs on the mainland. Small rodents are important prey for raccoon dogs on the mainland and on inhabited islands, but less important in the outer archipelago in early summer.     

Prevalence of dirofilarial infection in raccoon dogs in Japan.

The raccoon dog (Nyctereutes procyonoides viverrinus) is known to acquire canine heartworm (Dirofilaria immitis) infection. We surveyed the prevalence of heartworm infection in free-ranging raccoon dogs in the Nishi-Tama (Tokyo) and Kanagawa areas of Japan. A total of 75 raccoon dog carcasses, including 29 animals from the Nishi-Tama area and 46 from the Kanagawa area, were necropsied between 1992 and 1993. Eight out of 75 raccoon dogs were found to be infected (overall 10.7%). The prevalence of infection was 6 and 16% in Nishi-Tama and Kanagawa, respectively. Microfilarial production was observed in the uterus of one female adult dog.     

Arthrostoma miyazakiense (Nematoda: Ancylostomatidae) infection in raccoon dogs of Korea and experimental transmission to dogs

Arthrostoma miyazakiense (Nematoda: Ancylostomatidae) is a hookworm species reported from the small intestines of raccoon dogs (Nyctereutes procyonoides) in Japan. Five Korean raccoon dogs (N. procyonoides koreensis) caught from 2002 to 2005 in Jeollanam-do (Province), a southeastern area of South Korea, contained helminth eggs belonging to 4 genera (roundworm, hookworm, whipworm, and Capillaria spp.) and cysts of Giardia sp. in their feces. Necropsy findings of 1 raccoon dog revealed a large number of adult hookworms in the duodenum. These hookworms were identified as Arthrostoma miyazakiense based on the 10 articulated plates observed in the buccal capsule and the presence of right-sided prevulval papillae. Eggs of A. miyazakiense were 60-65 x 35-40 micrometer (av. 62.5 x 35 micrometer), and were morphologically indistinguishable from those of Ancylostoma caninum. The eggs were cultured to infective 2nd stage larvae via charcoal culture, and 100 infective larvae were used to experimentally infect each of 3 mixed-bred puppies. All puppies harbored hookworm eggs in their feces on the 12th day after infection. This is the first report thus far concerning A. miyazakiense infections in raccoon dogs in Korea, and the first such report outside of Japan.     

Evaluation of genetic biodiversity in farm-bred and wild raccoon dogs in Poland

The aim of the study was to analyze the intra- and inter-group diversity in farm-raised and wild raccoon dogs with the use of molecular markers. Genetic differences between the particular raccoon dog groups were observed, accompanied by a relatively high intra-group genetic variation. It was noted that the wild raccoon dogs were characterized by the highest genetic diversity, compared to the three study groups of farm-bred raccoon dogs. Wild raccoon dogs and farm-bred raccoon dogs constitute separate phylogenetic groups. The results obtained suggest that farm breeding may lead to differentiation into a different phylogenetic lineage than that of the wild raccoon dogs. In each case, the genetic distance between the animals bred on the individual farms was lower than the distances between the farm-raised and wild animals. Since the Polish farm breeding is based entirely on phenotype ranking, the genotype of "native" animals is still closely related to that of wild animals.     

Influence of prenatal stress on steroidogenesis in gonads of blue foxes

Handling is a source of stress for farm bred blue foxes. The influence of handling during the late gestational period was investigated in 10-day-old male and female blue foxes. Testosterone and estradiol were measured by RIA in the plasma, gonadal homogenates andin vitro incubates, from blue foxes of both sexes. The gonads were incubatedin vitro without or with human chorionic gonadotropin. In cubs of both sexes, the gonad weights and ovarian estradiol production were decreased by stress. The testicular testosterone and ovarian estradiol contents were increased in prenatally stressed cubs as compared to the controls. The testicular content and baselinein vitro production of testosterone were not affected by prenatal stress, but the testicular response to human chorionic gonadotropin was higher in the stressed group. This study suggests that prenatal stress induced by handling pregnant vixens may influence gonadal steroidogenesis and that this effect was more pronounced in female cubs.     

Ammonia levels in the whelping nests of farmed raccoon dogs and polecats

Ammonia concentrations were measured in the nests of farmed raccoon dogs (Nyctereutes-procyonoides Gray, 1834) and polecats (Mustela putorius) at weaning time. Ammonia levels in the nests of raccoon dogs and polecats varied from 1 to 43 ppm and from 0 to 5 ppm, respectively. In the raccoon dog, with increasing litter size, the ammonia concentrations tended to increase exponentially. In the polecat, no marked relationship between litter size and ammonia levels were found. The results show that no special adaptations are required in farm life because even the highest ammonia concentrations measured were below the harmful level.