Introduction: The aim of this study was to determine the effect of deoxynivalenol (DON), given alone or with bentonite (which eliminates mycotoxicity) in the diet of mink dams throughout mating, pregnancy, and lactation period to pelt harvesting, on the mechanical properties and geometry of their long bones.

Since April 2020, when the first SARS-CoV-2 infection was reported in mink and subsequently in mink farm workers in the Netherlands, it has been confirmed that human-to-mink and mink-to-human transmission can occur. Later, SARS-CoV-2 infections in mink were reported in many European and North American countries.

Many countries have reported severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infections in mink, and transmission back to humans has raised the concern of novel variants emerging in these animals. The monitoring system on Polish mink farms detected SARS-CoV-2 infection first in January 2021 and has been kept in place since then.

Since April 2020, when the first SARS-CoV-2 infection was reported in mink and subsequently in mink farm workers in the Netherlands, it has been confirmed that human-to-mink and mink-to-human transmission can occur. Later, SARS-CoV-2 infections in mink were reported in many European and North American countries. Samples from 590 mink from a total of 28 farms were tested by real-time RT-PCR. Whole genome sequences from one positive farm were generated and genetic relatedness was established. SARS-CoV-2 RNA was detected on a breeder farm with stock of 5,850 mink. Active viraemia was confirmed in individually tested samples with Ct values respectively between 19.4 and 29.6 for E and N gene fragments. Further testing of samples from culled animals revealed 70% positivity in throat swabs and 30% seropositivity in blood samples. Phylogenetic analysis of full-length nucleotide sequences of two SARS-CoV-2 isolates revealed that they belong to the 20B Nextstrain clade. Several nucleotide mutations were found in analysed samples compared to the reference Wuhan HU-1 strain and some of them were nonsynonymous. We report the infection of mink with SARS-CoV-2 on one farm in Poland and the results of subsequent analysis of virus sequences from two isolates. These data can be useful for assessment of the epidemiological situation of SARS-CoV-2 in Poland and how it endangers public health.

Introduction: Farm mink (Neovison vison) can be naturally exposed to T. canis and T. leonina pathogens on the farm. If mink were hosts, it would imply some veterinary public health as well as animal welfare issues. For this reason, the aim of the study was to determine whether mink might be definitive or paratenic hosts of these parasites. Material and Methods: Four groups of mink were infected with both parasite species using larvated eggs or feed containing mouse tissue previously infected with the parasites. Following inoculation, the infections were monitored in vivo by faecal examination for 14 weeks p.i., and then western blotting and ELISA were performed. Results: Coprology did not reveal any canine roundworm eggs, neither were nematodes found in mink intestines during post mortem examination. The specific IgG antibodies recognising excretory/secretory (ES) antigens of both parasite species were identified in mink sera. Single T. leonina tissue larvae were found in digested organs. Conclusions: Our results confirm that farm mink may contribute both T. canis and T. leonina infections. It was proved that farm mink were not their definitive hosts, and therefore mink faeces need not be considered a source of canine roundworm eggs in any soil it fertilises. Nonetheless, as farm mink may be a paratenic host for both parasite species, this may have some impact on the health and welfare of infected animals.

Introduction: The aim of the study was to investigate the mechanical and geometric properties as well as bone tissue and mineral density of long bones in mink dams exposed to deoxynivalenol (DON) since one day after mating, throughout gestation (ca. 46 d) and lactation to pelt harvesting. Material and Methods: Thirty clinically healthy multiparous minks (Neovison vison) of the standard dark brown type were used. After the mating, the minks were randomly assigned into two equal groups: nontreated control group and DON group fed wheat contaminated naturally with DON at a concentration of 1.1 mg·kg⁻¹ of feed. Results: The final body weight and weight and length of the femur did not differ between the groups. However, DON contamination decreased mechanical endurance of the femur. Furthermore, DON reduced the mean relative wall thickness and vertical wall thickness of the femur, while vertical cortical index, midshaft volume, and cross-sectional moment of inertia increased. Finally, DON contamination did not alter bone tissue density, bone mineral density, or bone mineral content, but decreased the values of all investigated structural and material properties. Conclusion: DON at applied concentration probably intensified the process of endosteal resorption, which was the main reason for bone wall thinning and the weakening of the whole bone.

Nursing sickness, the largest single cause of mortality in adult female mink (Mustela vison), is an example of a metabolic disorder, which develops when the demands for lactation require extensive mobilization of body energy reserves. The condition is characterized by progressive weight loss, emaciation, and dehydration with high concentrations of glucose and insulin in the blood. Morbidity due to nursing sickness can be as high as 15% with mortality around 8%, but the incidence is known to vary from year to year. Stress has been shown to trigger the onset of the disease and old females and females with large litters are most often affected. Increasing demand for gluconeogenesis from amino acids due to heavy milk production may be a predisposing factor. Glucose metabolism is inextricably linked to that of protein and fats. In obesity (or lipodystrophy), the ability of adipose tissue to buffer the daily influx of nutrients is overwhelmed (or absent), interfering with insulin-mediated glucose disposal and leading to insulin resistance. Polyunsaturated fatty acids of the n-3 family play an important role in modulating insulin signalling and glucose uptake by peripheral tissue. The increasing demand on these fatty acids for milk fat synthesis towards late lactation may result in deficiency in the lactating female, thus impairing glucose disposal. It is suggested that the underlying cause of mink nursing sickness is the development of acquired insulin resistance with 3 contributing key elements: obesity (or lipodystrophy), n-3 fatty acid deficiency, and high protein oxidation rate. It is recommended that mink breeder females be kept in moderate body condition during fall and winter to avoid fattening or emaciation. A dietary n-3 fatty acid supplement during the lactation period may be beneficial for improved glycemic control. Lowering of dietary protein reduces (oxidative) stress and improves water balance in the nursing females and may, therefore, prevent the development and help in the management of nursing sickness. It is also surmised that other, thus far unexplained, metabolic disorders seen in male and female mink may be related to acquired insulin resistance.

The impact of dietary sodium on the incidence of nursing sickness in mink dams and on the average litter biomass of 28 and 42 day old kits was studied. One group (n = 115 including 12 barren females) was given a standard feed mixture with a natural content of 0.53 g NaCl/MJ and another group (n = 115 including 8 barren females) was given the same feed mixture supplemented with NaCl to a final content of 1.00 g/MJ. The average dam weight at weaning was significantly lower (P < 0.001) and the incidence of nursing sickness during the last part of the lactation period 3 times higher in the nonsupplemented group. The average litter biomass at weaning did not differ between the 2 experimental groups. A number of biochemical markers of preclinical nursing sickness, e.g. plasma aldosterone and osmolality, Na+ and Cl concentrations in plasma and urine, were studied during the last part of the lactation period and at weaning in 20 dams of the nonsupplemented group, in 10 dams of the salt supplemented group and, for comparison, in 5 + 5 barren females on the day corresponding to day 34 after parturition in nursing mink. The nonsupplemented group had significantly lower concentrations of sodium and chloride in plasma and urine and a significantly higher concentration of plasma aldosterone as compared to the salt supplemented group. Distinct signs of relative salt deficiency and preclinical nursing sickness thus characterized the nonsupplemented group throughout this period, while more blurred hints of electrolyte imbalances were noticed in the sodium chloride supplemented group at weaning. A beneficial effect of salt supplementation on the incidence of nursing sickness was shown; however, it remains unclear whether salt deficiency can cause nursing sickness or whether salt acts as an appetite stimulant preventing inanition and the development of the disorder.

Pododermatitis is a disease of concern for mink breeders in Canada and worldwide, as it causes discomfort and lowers the breeding rates on farms affected by the disease. Unfortunately, the etiology and pathogenesis of pododermatitis are still unknown. In this study, we compared Staphylococcus spp. and Streptococcus canis isolates from healthy mink with isolates from animals with pododermatitis on 2 farms in Ontario. Almost all hemolytic Staphylococcus spp. isolated were shown to be Staphylococcus delphini Group A by 16S ribosomal ribonucleic acid (rRNA) sequence analysis and polymerase chain reaction (PCR). Pulsed-field gel electrophoresis (PFGE) did not reveal any S. delphini or S. canis clonal lineages specifically associated with pododermatitis, which suggests that these bacteria do not act as primary pathogens, but does not dismiss their potential roles as opportunistic pathogens. While S. delphini and S. canis were the most prevalent bacterial pathogens in mink pododermatitis, they were also present in samples from healthy mink. Arcanobacterium phocae is occasionally isolated from pododermatitis cases, but is difficult to recover with conventional culture methods due to its slow growth. A quantitative real-time PCR was developed for the detection of A. phocae and was tested on 138 samples of footpad tissues from 14 farms. The bacterium was detected only in pododermatitis-endemic farms in Canada and was at higher concentrations in tissues from infected footpads than in healthy tissues. This finding suggests that A. phocae is involved in the pathogenesis of pododermatitis.

Hemorrhagic pneumonia in mink is a fatal disease caused by Pseudomonas aeruginosa. Very little is known about P. aeruginosa in relation to genotype and the mechanisms underlying antimicrobial resistance in mink. A total of 110 P. aeruginosa samples were collected from mink from Chinese mink farms between 2007 and 2015. Samples underwent molecular genotyping using pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST), antimicrobial susceptibility and its mechanism were investigated at the molecular level. The PFGE identified 73 unique types and 15 clusters, while MLST identified 43 (7 new) sequence types (ST) and 12 sequence type clonal complexes (STCC). Sequence types and PFGE showed persistence of endemic clones in cities Wendeng (Shandong, China) and Dalian (Liaoning, China), even in different timelines. The MLST also revealed the gene correlation of the mink P. aeruginosa across different time and place. The ST1058 (n = 14), ST882 (n = 11), and ST2442 (n = 10) were the predominant types, among which ST1058 was the only one found both in Shandong province and Dalian (Liaoning, China). The MLST for P. aeruginosa infection in mink was highly associated with that in humans and other animals, implying possible transmission events. A small proportion of mink exhibited drug resistance to P. aeruginosa (9/69, 13%) with resistance predominantly to fluoroquinolone, aminoglycoside, and β-lactamase. Eight strains had mutations in the quinolone-resistance determining regions (QRDR). High proportions (65%; 72/110) of the fosA gene and 2 types of glpt deletion for fosmycin were detected. Furthermore, in the whole genome sequence of one multidrug resistant strain, we identified 27 genes that conferred resistance to 14 types of drugs.