Hormonal induction of oestrus and pregnancy in anoestrous ferrets (Mustela putorius furo)

Three doses of FSH were tested for their ability to induce oestrus in ferrets. A dose of 0.25 mg, administered twice daily, induced oestrus and breeding in most females within 6-13 days. Addition of 5 i.u. hCG during the final stages of follicular development enhanced the percentage of females with implantation sites (85%), and 23% of the ferrets so treated gave birth to kits, none of which survived for more than 3 days. This may have been due to insufficient prolactin secretion and thus inadequate luteal maintenance and milk production, as these females were maintained on a short-day photoperiod.     

Courtship patterns in induced oestrous and natural oestrous domestic ferrets (Mustela putorius furo)

Ten anoestrous female domestic ferrets (Mustela putorius furo) had estrus artificially induced by injection of porcine follicle stimulating hormone. Pre-copulatory activities were defined, quantitatively analyzed, and compared to the pre-copulatory activities of 10 control females placed with the same male ferrets. Lag sequential analysis was used to prepare the behavioral matrices. Matrices were compared with an equality of proportions test. Courtship patterns between the 2 groups did not differ significantly.     

Urolithiasis in ferrets (Mustela putorius).

Urinary calculi was observed frequently in ferrets which were from a group used for influenza research. They were submitted for necropsy with various clinical signs. The calculi were composed of magnesium ammonium phosphate hexahydrate and were found in the pelvis of the kidney, urinary bladder and urethra. Crystals of undetermined nature occasionally were observed in the kidneys.     

Characterization of transforming growth factors beta1 and 2 in ferrets (Mustela putorius furo)

Unwanted scar tissue after surgical procedures remains a central problem in medicine. Nowhere is this problem more evident than within the pediatric airway, where excess scarring, termed subglottic stenosis, can compromise breathing. Recent advances in molecular biology have focused on ways to decrease scar formation through understanding of the wound repair process. Transforming growth factor beta (TFGbeta) plays a central role in this pathway. Ferrets serve as an ideal model for the pediatric airway, and reproduction of subglottic stenosis in ferrets is possible. However, ferret cytokine profiles have not been established. In this study, we characterized the presence and nucleotide sequence of the TGFbeta1 and 2 genes in ferrets by using total RNA isolated from airways. Amino acid sequence homology between human and ferret was determined to be 96.6% for TGFbeta1 and 99.3% for TGFbeta2. Given the nearly total homology between TGFbetas of ferret and human origin, the ferret may serve as an ideal model for future molecular studies.     

Experimental infection of domestic ferrets (Mustela putorius furo) and Siberian polecats (Mustela eversmanni) with Yersinia pestis

Eight domestic ferrets (Mustela putorius furo) and two Siberian polecats (M. eversmanni) were inoculated subcutaneously with 12 to 1.2 x 10(7) Yersinia pestis originally isolated during an epizootic of plague in white-tailed prairie dogs (Cynomys leucurus) near Meeteetse, Park County, Wyoming (USA) in 1985. None of the ferrets or polecats developed clinical signs of disease which suggested that black-footed ferrets (M. nigripes), a congener, also would be resistant to plague. All animals receiving greater than or equal to 1.2 X 10(3) organisms produced serum antibodies detected by the passive hemagglutination test with titers peaking at 1:1,024 and remaining positive until at least 219 days postinoculation. Sera collected from 12 free-ranging black-footed ferrets near Meeteetse in 1984 and 1985 were negative for antibodies against Y. pestis. Prevalence of antibodies against Y. pestis was high in other carnivores collected from the same area in 1986.     

A panel of microsatellite markers for genetic studies of European polecats (Mustela putorius) and ferrets (Mustela furo)

We report a panel of 12 microsatellite markers, including nine novel polymorphic loci isolated in the European polecat and three loci previously developed in closely related species, for genetic studies of polecats and ferrets. We tested the panel at fine geographic scales in polecat and domestic ferret populations of Britain and Portugal and at a broad geographic scale, using 50 polecat samples from across Western Europe. At the fine geographic scales, we recorded one to five alleles per locus and observed and expected heterozygosities ranging from 0 to 0.80 and from 0 to 0.74, respectively. These values increased markedly in the European sample of polecats. No linkage disequilibrium was detected between any pair of loci and all genotypic frequencies complied with Hardy–Weinberg equilibrium expectations. The microsatellite panel allowed the molecular discrimination of polecats and domestic ferrets in Britain, where hybridisation between the two species has been documented. Thus, these loci may be useful not only in genetic studies of polecats and ferrets but also in studies to assess hybridisation between these two mustelid species.     

The ferret, Mustela putorius furo, as a new species in toxicology.

Comprehensive studies on the haematology, urine chemistry, serum chemistry and gross pathology have been carried out and reported. Seasonal weight changes were confirmed and were initiated, together with sexual activity, when ferrets were brought in to a constant temperature (18-19 degrees C) and 14-hour daylight cycle during the winter months. Levels of haemoglobin, erythrocytes and haematocrit were higher than in most common laboratory species. Similarly, serum electrolytes and glucose levels were higher than in Wistar rats or beagle dogs. Ovaries, uteri and testes displayed a seasonal maturation and atrophy. All other parameters were similar to common laboratory species.     

Identification of a tyrosinase (TYR) exon 4 deletion in albino ferrets (Mustela putorius furo)

Albinism is due to a lack of pigmentation in hair, skin and eye, and has been shown to occur in several animal species. Mutations of the tyrosinase (TYR) gene account for albinism in domestic cats, rabbits, cattle, mice and rats. In this study, we demonstrate that a TYR mutation accounts for albinism in the ferret (Mustela putorius furo). The coding sequence of the five exons of TYR was determined in genomic DNA from wild-type pigmented 'sable' coloured and albino ferrets. It was not possible to amplify TYR exon 4 in albino ferrets originating from different breeds. The deletion of exon 4 in albino ferrets was confirmed by Southern blot hybridization of genomic DNA from albino and pigmented ferrets. This is the first report of a deletion of a TYR exon in a non-human mammal.     

Experiments and a model examining learning in the area-restricted search behavior of ferrets (Mustela putorius furo)

Area-restricted searches have been described as important componentsof the foraging behavior of many organisms. It is unclear, however,whether individual foragers can use learning to fine-tune theirsearches, or even whether these searches are efficiently performed.I used a simulation model to make qualitative predictions aboutsearch behavior in a laboratory system. The simulation modelindicates that the sinuosity and path length of searches stronglyaffect search efficiency. The model predicts that, for a rate-maximizingforager, path length should increase and search sinuosity shoulddecrease as prey become less clumped. Foraging animals may thereforebe selected to learn the path length and sinuosity of searchesin response to changing degrees of dumping of prey. These predictionswere tested in a laboratory system involving ferrets (Mustelaputorius furo) foraging for oil-drop "prey items." Search pathschanged in a graded manner to experimental manipulations ofthe dumping of prey. As predicted by the model, ferrets learnedto perform longer and less sinuous search paths as prey becameless clumped. This study provides the first evidence that area-restrictedsearch behavior is learned and can be fine-tuned to efficientlyexploit different spatial distributions of food.     

Dracunculus insignis: experimental infection in the ferret, Mustela putorius furo

The laboratory study of dracunculiasis has suffered from the lack of a suitable, readily available animal model. We have been able to experimentally infect ferrets. Mustela putorius furo, with the North American dracunculid, Dracunculus insignis. Ferrets were inoculated with 75 to 100 infective larvae and were necropsied 90 to 240 days later. Guinea worms were recovered from 10 (56%) of 18 ferrets. A total of 44 worms were recovered, for an average of 4.4 worms per infected ferret. Gravid female worms were recovered as early as 128 days postinoculation. Thirteen (87%) of 15 gravid female worms were recovered from the extremities. Living male worms were recovered at 200 days of age, indicating that not all male worms die shortly after mating. First-stage larvae recovered from gravid females as early as 200 days of age were found to be infective to the copepod, Acanthocyclops vernalis. These observations suggest that the ferret is an excellent laboratory animal for dracunculiasis research.     

Comparative semen cryopreservation in ferrets (Mustela putorius furo) and pregnancies after laparoscopic intrauterine insemination with frozen-thawed spermatozoa

A study was conducted to determine an optimum technique for semen cryopreservation and the biological competence of frozen-thawed ferret spermatozoa. Fifty-two fresh electroejaculates from 4 males were evaluated for sperm percentage motility, forward progressive motility, motility index (SMI) and acrosomal integrity. To determine the optimum temperature for maintaining sperm motility in vitro and the influence of glycerol on sperm motility, seminal aliquants were diluted in TEST diluent (containing either 0 or 4% glycerol) and maintained at 25 degrees or 37 degrees C. For cryopreservation, semen was diluted in each of 3 cryodiluents (TEST, PDV, BF5F), cooled for 30 min at 5 degrees C and pelleted on solid CO2 or frozen in 0.25 ml straws (20 degrees C/min to -100 degrees C). Following thawing, SMI and acrosomal integrity were determined. Ten females with maximum vulval swelling were given 90 i.u. human chorionic gonadotrophin and laparoscopically inseminated in utero with spermatozoa previously frozen using the optimum diluent and freeze-thaw method. The maintenance temperature of 25 degrees C was superior (P less than 0.05) to 37 degrees C for sustaining sperm motility, and glycerol did not influence (P greater than 0.05) motility for up to 11 h of culture. After thawing, motile spermatozoa were recovered in all treatment groups, but sperm motility and normal acrosomal ratings were highest using the PDV diluent, the pelleting method and thawing at 37 degrees C (P less than 0.05). Seven of the 10 ferrets (70%) inseminated with spermatozoa frozen by this approach became pregnant and produced 31 kits (mean litter size 4.4; range 1-9 kits).(ABSTRACT TRUNCATED AT 250 WORDS)     

Pregnancy toxemia in the European ferret (Mustela putorius furo).

BACKGROUND AND OBJECTIVE: Pregnancy toxemia may lead to appreciable mortality among jills and their offspring. The objective of this report was to increase awareness of the disease, its likely cause, and practical prevention and treatment measures. METHODS: Ten cases of pregnancy toxemia were evaluated. Jills were in late gestation (mean, 38 days; range, 34 to 42 days) and had large litters (mean, 11.5 kits; range, 7 to 15 kits). RESULTS: The most common clinical signs of disease were lethargy, inappetence, dehydration, and excess shedding. Hematologic and clinical biochemical abnormalities included anemia (4 of 8 jills tested), hypoproteinemia (5 of 7), azotemia (7 of 7), hypocalcemia (5 of 6), hyperbilirubinemia (3 of 3), and high liver enzyme activities (6 of 6). Two jills were found dead; two jills were euthanized, six received supportive treatment, and cesarean section was performed on five. The three jills that survived tended to have less pronounced azotemia, hypoproteinemia, and liver enzyme activity increases and were not anemic. Hepatic lipidosis was observed grossly in all jills that died and was confirmed by histologic examination in four jills. CONCLUSIONS: Pregnancy toxemia in ferrets resembles metabolic diseases in several other animal species and requires aggressive treatment, including supportive care, nutritional supplementation, and cesarean section. Maintaining adequate nutrition and avoiding stress late in gestation may prevent the disease.     

Brugia pahangi and Dirofilaria immitis: experimental infections in the ferret, Mustela putorius furo.

Ferrets were inoculated with 160 third-stage larvae of the filarial nematode Brugia pahangi, followed 23 days later by 15 larvae of another filarial nematode, Dirofilaria immitis. Other ferrets received only one of these species. Microfilaremia developed in some ferrets with single infections of each species and in some ferrets with dual infections. The nature of the experiment did not permit a thorough study of microfilaremia, but B. pahangi microfilariae were found in numbers as high as 15,650/ml. At necropsy, approximately 8 months after inoculation, adult B. pahangi were recovered from the lymphatic vessels of all 8 ferrets inoculated only with that species, the recovery rate (based on 6 animals only) varying from 2 to 50% of the inoculum (mean 25%). Adult D. immitis were recovered from the heart of all three ferrets inoculated only with that species, the recovery rate being 7, 47, and 60% (mean 38%) of the inoculum. All 5 ferrets inoculated with both species yielded both adult B. pahangi (6 to 23%, mean 16% of inoculum) and adult D. immitis (13 to 67%, mean 37% of inoculum). It is concluded that the ferret is highly susceptible to both species and that concurrent infections with both species may readily be established.     

Transcervical artificial insemination in the domestic ferret (Mustela putorius furo)

The research was undertaken to develop a successful nonsurgical procedure for artificially inseminating ferrets. A fiberoptic endoscope used in conjunction with a specially designed speculum and catheter permitted cervical catheterization and intrauterine insemination. Sperm were collected from the cauda epididymides of 10 discarded breeder males; the number of sperm in diluted samples used for insemination ranged from 4.4–13.6 × 10⁶/100 μl with progressive motility of sperm ranging from 40 to 60%. Sperm collected from each male were diluted with an egg-yolk extender (TEST) and used to inseminate 8–12 females, with deposition of sperm intravaginally or transcervically into the uterine body 0 or 24 hr after an ovulatory injection of human chorionic gonadotropin (hCG). The vaginal inseminations were used as a control, and no pregnancies resulted after insemination of 26 females. Intrauterine inseminations resulted in 4/24 (17%) of the ferrets pregnant when hCG administration was coincident with insemination, and 19/24 (79%) of the ferrets were pregnant when inseminations were done 24 hr after hCG administration. All inseminated females were euthanized on day 20 after insemination to count fetuses. The mean number of fetuses was 3.1 (range, 1–8). The number (millions) of motile sperm inseminated (X) had a significant effect on the percentage of fetuses (Y). Regression analysis indicated a linear relationship between the two variables, with an R² value of 0.99 and a line of best fit described by the equation Y = 0.029 + 0.034 X. This paper is the first report of transcervical artificial insemination in the domestic ferret (Mustela putorius furo). The method can serve as a model for application to ferrets and other mammals, particularly endangered species. Zoo Biol 17:393–404, 1998. © 1998 Wiley-Liss, Inc.     

Activation of two types of fibres in ferret,Mustela putorius furo,cremaster muscle

Summary Some contractile, histochemical, morphological and electrophysiological properties of ferret, Mustela putorius furo, cremaster muscle have been estimated. Histochemical fibre typing revealed the presence of two types of fibres (type I 66.2%, type II 33.8%). Morphometry performed on ATPase-stained transverse sections showed that type I was composed of a large amount (40%) of small(<400 m²) cells. In mammalian Ringer two groups of fibres could be recognized on the basis of the values of resting potential (-69.7 mV and-59.1 mV) and intracellular sodium activity (8.3 mmol·l^-1 and 14.1 mmol·l^-1, respectively). In experiments on fibre bundles, the elevation of extracellular potassium concentration to 15–200 mmol·l^-1 produced contractures that consisted of a well-defined transient or phasic tension followed by a sustained or tonic tension. Properties of activation and inactivation of the tension analysed in small bundles of cut fibres (lengths 0.5–1.0 cm) were of fast- and slow-twitch type for phasic and tonic phase, respectively. In contrast to the phasic component of K contractures, the tonic phase was abolished by Ca²⁺ withdrawal and inhibited by Ni²⁺, Cd²⁺, Co²⁺, Gd³⁺ and gallopamil (D600). In Ca²⁺-free medium the sustained tension was restored by adding Sr²⁺. It is concluded that in ferret cremaster muscle the presence of slow-twitch fibres would give rise to the tonic component of the K contracture in which an extracellular source of activator Ca²⁺ is involved. The ability of these fibres to contract with a maintained tension for prolonged periods of time might participate in the temperature regulation of the testes.Abbreviations a _i ^Na intracellular sodium activity - ATPase myosin adenosine triphosphatase - D600 gallopamil - E _m membrane potential - E _r resting potential - EDL muscle, extensor digitorum longus muscle - HEPES N-2-hydroxyethylpiperazine-N-2-ethanesulphonic acid - e.c. excitation-contraction - SDHase succinate dehydrogenase - NADHase nicotinamide adenine, dinucleotide hydrogen-diaphorase - SOL muscle, soleus muscle - T time constant of relaxation - TEACI tetraethylammonium chloride - [Ca]_o, [K]_o, [Na]_o extracellular calcium, potassium, sodium concentration     

Use of a gonadotropin releasing hormone agonist implant as an alternative for surgical castration in male ferrets (Mustela putorius furo)

Surgical castration in ferrets has been implicated as an etiological factor in the development of hyperadrenocorticism in this species due to a castration-related increase in plasma gonadotropins. In search for a suitable alternative, the effect of treatment with the depot GnRH-agonist implant, deslorelin, on plasma testosterone concentrations and concurrent testes size, spermatogenesis, and the typical musky odor of intact male ferrets was investigated. Twenty-one male ferrets, equally divided into three groups, were either surgically castrated, received a slow release deslorelin implant or received a placebo implant. Plasma FSH and testosterone concentrations, testis size and spermatogenesis were all suppressed after the use of the deslorelin implant. The musky odor in the ferrets which had received a deslorelin implant was less compared to the ferrets which were either surgically castrated or had received a placebo implant. These results indicate that the deslorelin implant effectively prevents reproduction and the musky odor of intact male ferrets and is therefore considered a suitable alternative for surgical castration in these animals.     

Dirofilaria immitis: experimental infections in the ferret (Mustela putorius furo)

The ferret, Mustela putorius furo, was found to be susceptible to Dirofilaria immitis infection when exposed to low (14) or high (280-420) numbers of infective larvae harvested from Aedes aegypti. Eight ferrets (half of them cortisonized) were inoculated subcutaneously with 14 larvae each. All of them were subsequently found to harbor D. immitis in the heart, and all but one of them had worms of both sexes. Six of these ferrets were examined for microfilaremia at 31 to 35 weeks after inoculation; 3 were positive (one observed only at postmortem examination) and there was evidence that fertilization of female worms had occurred in one other. Females up to 25.5 cm and males up to 16.0 cm were recovered. There was no evidence that the cortisonization of some ferrets had affected the infections. Both male and female ferrets became infected. Four cortisonized ferrets were inoculated with 280 or 420 larvae of D. immitis (divided equally between subcutaneous and intraperitoneal routes). All of them died 16 to 18 weeks after inoculation, yielding 102 to 125 immature D. immitis. In these lethal infections, worms were recovered from the heart and adjoining vessels, and also from vascular and extravascular sites throughout the body.     

Comparison of black-footed ferret (Mustela nigripes) and domestic ferret (M. putorius furo) courtship activity

Because of the scarcity of the endangered black-footed ferret (Mustela nigripes) and the amount of knowledge necessary for their conservation, surrogate research can play an important role in recovery. In this paper, we investigate surrogate behavioral research potential by comparing courtship behavior of the black-footed ferret to the congeneric domestic ferret (M. putorius furo). Ten female domestic ferrets were bred to five male domestic ferrets and eight female black-footed ferrets were bred to five black-footed ferret males. Courtship activities were defined, analyzed, and quantitatively compared between both groups. Lag sequential analysis of was used to prepare the behavioral matrices, and matrix cells were compared between groups with an equality of proportions test. Courtship patterns did not differ significantly between the two closely related species, and the domestic ferret would probably be an adequate surrogate for reproductive behavior research on the black-footed ferret.