Effects of Different Sources and Levels of Copper on Growth Performance,Nutrient Digestibility,and Elemental Balance in Young Female Mink (Mustela vison)

An experiment was conducted in a 3?×?3?+?1 factorial experiment based on a completely randomized design to evaluate the effects of different sources of copper on growth performance, nutrient digestibility and elemental balance in young female mink on a corn–fishmeal-based diet. Animals in the control group were fed a basal diet (containing 8.05 mg Cu/kg DM; control), which mainly consisted of corn, fish meal, meat bone meal, and soybean oil, with no copper supplementation. Minks in other nine treatments were fed basal diets supplemented with Cu from reagent-grade copper sulfate, tribasic copper chloride (TBCC) and copper methionate. Cu concentrations of experiment diets were 10, 25, and 40 mg/kg copper. A metabolism trial of 4 days was conducted during the last week of experimental feeding. Final body weight and average daily gain increased (linear and quadratic, P?<?0.05) as Cu increased in the diet; maximal growth was seen in the Cu25 group. Cu supplementation slightly improved the feed conversion rate (P?=?0.095). Apparent fat digestibility was increased by copper level (P?=?0.020). Retention nitrogen was increased by copper level (linear, P?=?0.003). Copper source had a significant effect on copper retention with Cu-Met and copper sulfate treatments retention more than TBCC treatments (P?<?0.05). Our results indicate that mink can efficiently utilize added dietary fat and that Cu plays an important role in the digestion of dietary fat in mink, and mink can efficiently utilize Cu-Met and CuSO₄.     

Effects of Different Sources and Levels of Zinc on Growth Performance,Nutrient Digestibility,and Fur Quality of Growing-Furring Male Mink (<Emphasis Type="Italic">Mustela vison</Emphasis>)

The objective of this study was to investigate the effects of different sources and levels of zinc (Zn) on growth performance, nutrient digestibility, serum biochemical parameters, and fur quality in growing-furring male mink. Animals in the control group were fed a basal diet with no Zn supplementation. Mink in the other nine treatments were fed the basal diet supplemented with Zn from either grade Zn sulfate (ZnSO₄·7H₂O), Zn glycinate (ZnGly), or Zn pectin oligosaccharides (ZnPOS) at concentrations of either 100, 300, or 900 mg Zn/kg dry matter. One hundred and fifty healthy 15-week-old male mink were randomly allocated to ten dietary treatments (n = 15/group) for a 60-day trial from mid-September to pelting in December. Mink in the Zn-POS groups had higher average daily gain than those in the control group (P < 0.05). Zn source slightly improved the feed/gain (P = 0.097). N retention was increased by Zn addition (P < 0.05). Mink supplemented with dietary Zn had higher (P < 0.05) pancreas Zn level than the control group. Fur length was greater (P < 0.05) in ZnGly and ZnPOS groups compared with the control. In addition, fur length and fur density increased (linear, P < 0.05) with Zn supplementation in the diet. In conclusion, our data show that dietary Zn addition improves growth performance by increasing nitrogen retention and fat digestibility in growing-furring mink and Z-POS is equally bioavailable to mink compared to ZnGly.     

Metrical and Non-metrical Skull Variations in Norwegian Wild Mink (Mustela vison Schreber)

Variations in fifteen metrical measurements and six non-metrical traits in 131 mink skulls were investigated. The skulls were subdivided geographically into three samples: Eastern Norway, Western Norway and Trøndelag. Separation into juveniles and adults was in accordance with the criterion that all sutures are closed in adults. This seemed to work well. No age or sex variations were found in the non-metrical traits. Relatively little geographic variation found in either the metrical measurements or the non-metrical traits indicated little genetic variation. Gene-flow is regarded as one of the reasons for this.     

Sexual Dimorphism in the Skull of the Feral American Mink (Mustela vison Schreber)

Sexual dimorphism in the skull of the feral American mink is discussed, based on 15 measurements of 53 adults from southern Norway. The differences in means are highly significant. Variation is found to be greatest in males. Sexual dimorphism is thought to be an adaptation for different reproductive roles of the sexes in a polygynous mating system with lack of male parental care.     

Sex Identification in the Mink (Mustela vison Schreber) by Metrical Measurements of the Skull

The dental length and length of the first molar in the upper jaw of mink are characteristics used to estimate a discriminant function for sex identification of Norwegian populations. Reliability of the method is theoretically 93.2%.     

Glucose Metabolism and Regulation in Lactating Mink (Mustela Vison) - Effects of Low Dietary Protein Supply

Eighteen lactating mink raising litters of 6 to 7 kits were fed ad libitum from parturition on diets with 32% of ME derived from protein and decreasing fat:carbohydrate ratios [high fat:low carbohydrate (HFLC): 67:1, medium fat:medium carbohydrate (MFMC): 52:16, low fat:high carbohydrate (LFHC): 37:31]. Four weeks post partum the dams were fitted with a jugular vein catheter, and the experiment started with a 3 hours fasting period, after which the dams were fed 210kJ ME of the experimental diets. Blood samples were collected 10 and 5min before feeding and 30, 60, 90, 120, 150 and 180min postprandially. Two hours postprandially a single dose of 50µCi U-¹⁴C-labelled glucose was administered to each dam and blood samples were collected 5, 10, 20, 30, 45 and 60min after the tracer administration. Plasma concentrations of glucose and insulin 30 to 120min postprandially were higher in dams fed the LFHC diet, than in dams fed the HFLC diet, values for dams fed the MFMC diet being intermediate. Plasma glucagon concentrations were not significantly affected by dietary treatment. The glucagon:insulin ratios decreased postprandially in all dams, the response being significant in dams fed the LFHC diet. Plasma concentrations of urea were not significantly affected by dietary treatment. Plasma FFA concentrations tended to increase postprandially in dams fed the HFLC diet. Glucose turnover rates were approximately 4.0% permin in all dams, irrespective of dietary treatment. However, the daily glucose flux was lower in dams fed the HFLC diet than in dams fed the LFHC diet, and tended to be lower than in dams fed the MFMC diet. In conclusion, a dietary protein supply of 32% of ME simultaneously with a carbohydrate supply of 16% or 31% of ME had no adverse effects on glucose homeostasis or glucose metabolism in lactating mink.     

The Pineal Gland of the Mink, Mustela vison: Light-, Fluorescence- and Electron Microscopical Studies

The pineal gland of normal and experimental female mink has been studied by light-, fluorescence- and electron microscopy. The general structure of the mink pineal is described. Two main cell types are recognized. One, termed pinealocyte, predominates in number. Though slight morphological differences (e.g. electron density of the cytoplasm and content of organelles) were observed, this study indicates that the pineal of mink only contains one single population of pinealocytes. The other, termed glial cell, inserted between the pinealocytes, is characterized by the presence of elongated processes, containing microfilaments. Different treatments (ovariectomy and LH—RH administration) and different endocrine states during the year induced morphological changes in the pinealocytes. A rich network of nerve fibres containing electron-dense granules (40–50 nm) is observed. Microspectrofluorometrically these fibres exhibit the spectral characteristics of cateholamines. All the pinealocytes show a yellow fluorescence. This cellular fluorophor shows the same microspectrofluorometric characteristics as does the fluorophor of serotonin. Occasionally, synaptic ribbons are observed in the perikaryon and the processes of the pinealocytes. A large number of cellular junctions between pinealocytes and endothelial cells is present. Their presumed function(s) are discussed. There is evidence of a blood-brain barrier within the mink pineal gland.     

A comparison of the feeding biology of Mink Mustela vison and otter Lutra lutra

The feeding habits and prey selectivity of Mink Mustela vison and otters Lutra lutra were compared in two localities in Devon: a eutrophic lake and a moorland river, in which both species occurred and had access to the same prey populations. The effects of prey availability on the predators' diets were assessed by comparing prey consumed, as revealed by scat analysis, with estimates of prey abundance and size range. Otters specialized in fish at all times of year but showed seasonal variation in species taken. Selection for slow-moving fish and seasonal changes in behaviour of some fish species were the probable causes of this variation. Otters diversified more into non-fish food in summer, when fish availability was reduced. The main alternative prey in the lacustrine habitat was waterfowl, but in the riverine habitat, rabbits. Mink were more generalized carnivores, taking a variety of fish, waterside and terrestrial prey in all seasons. These three prey categories were taken to an almost equal extent in the lake but terrestrial prey dominated in the riverine habitat. Fish were taken most frequently in winter and birds and mammals in summer. Neither predator showed selection in respect of prey size. In each area, about one third of the otter and Mink diets was common to both species. Fish was the principal group of the shared component, and dietary overlap in respect of them was greatest in autumn and winter. In view of the dietary preferences of each predator, the existence of alternative prey items and limited degree of dietary overlap, it is considered unlikely that the two species competed for food to any extent. Other factors must therefore be responsible for the spread of feral Mink and the decline in otter populations in many parts of Britain.     

Cytodifferentiation in the Pars Distalis of the Pituitary Gland in the Fetal and Juvenile Mink,Mustela vison

Hypophysial tissue of mink (Mustela vison) embryos, newborn young and kits aged 1 day to 27 weeks was examined by light and electron microscopy. Among the embryos five different ontogenetic stages were distinguished. It appears that the primordium of the pituitary gland differentiates in early embryonic life. Several types of glandular cells containing variable amounts of granular material were recognizable by the time of birth. The role of the granular cells and the origin of the lumina in the pars distalis are speculated upon (in the Discussion).     

Effect of aleutian gene on mink (Mustela vison) growth

The correlation between the skin size of Mustela vison mink and the combination of the alleles of aleutian colour gene has been shown. The studied relation can be presented as ppAa > ppAA > ppaa.     

Fine Structure of the Pars Distalis of the Pituitary Gland in the Female Mink,Mustela vison

Pituitary glands of intact and experimental adult females of mink, Mustela vison, were examined by electron microscopy. Conventional methods involving removal of endocrine glands (ovaries and adrenals), administration of radioactive isotope, ¹³¹I, blocking agents (thiouracil and metopirone) and hormones (thyroxine, hydrocortisone, thyrotropin and luteinizing hormone releasing hormones) were employed. Five categories of granular cells were distinguished both by their ultrastructural characteristics and qualitative changes throughout the year and following different treatments. The cell types are described and their functions discussed. From conventional electron microscopical studies it proved difficult to draw any satisfactory conclusions about the gonadotropic cells. Further investigation by means of immunocytochemistry and radioimmunoassay techniques is required to determine, whether the presumptive gonadotropic cell type produces both FSH and ICSH or only one of these hormones. Morphologically two types of agranular cells were identified. Their morphological inter-relationship and function are discussed briefly.     

Ultrasonographic analysis of gestation in mink (Mustela vison)

Mink are seasonal breeders that display an obligate delay preceding implantation and a post implantation gestation of 31 d. The purpose of this study was to evaluate gestational parameters in mink by ultrasonography. A total of 92 female mink were mated twice during the period from March 2 to 20. The mink were scanned once and allowed to whelp (n=55); or scanned at 3 to 5-d intervals until parturition (n=13); or immediately subjected to autopsy (n=24) after scanning. Embryonic age was calculated from the date of parturition or from crown rump length. Uterine swelling diameter and fetal head size were correlated with embryonic age. The gestational sac grew rapidly once implantation had occurred. Uterine swellings of 4 to 5 mm in diameter were found on Days 2 to 4 post implantation and increased through Days 18 to 20, at which time they began to elongate due to the longitudinal growth of the fetus. Fetal cardiac activity could be detected on Days 10 to 12 post implantation in live embryos. The heart frequency was 198 +/- 3.0 beats per minute and did not vary from Days 12 to 30 post implantation. Fetal head diameter of 5 mm was first detected on Day 19 post implantation and grew gradually to 9 to 10 mm at parturition. It was not possible to accurately assess the number of conceptuses in utero. We conclude that ultrasonography can be employed in mink to diagnose pregnancy, to predict the parturition date and to determine the presence of live fetuses.     

The food of feral mink (Mustela vison) in Scotland

Feral American mink ( Mustela vison ) thrive in Scotland. The potential impact of the mink on the native fauna was investigated through its food. Fifty-five stomachs and 33 scats were analysed by identifying the indigestible remains. Fish formed the main prey (49% occurrence) and birds and mammals 28% and 23% respectively. Most of the fish eaten were Salmonidae (brown trout and salmon). No remains of eels were found.
Mink may compete with otters for food, but the smaller prey taken by the mink and its greater use of land separates it from the otter. Mink seem to be occupying a vacant feeding niche in Scotland.     

Mapping of 53 loci in American mink (Mustela vison)

Fifty-three genes were mapped in the American mink genome using polymerase chain reaction (PCR)-based analysis of a Chinese hamster-American mink somatic cell hybrid panel. Heterologous primers designed for cat gene mapping were used in this study. Forty-nine of these loci were localized into expected chromosome regions according to Zoo-FISH data, whereas four loci--ALPL, CDC20, ERF-2, and Fc(Mv)23617--were mapped out of expected conserved regions. PCR products amplified with primers corresponding to these four markers were partly sequenced and verified using BLAST. The results showed the homology to be more than 90% between mink and human or cat counterparts. At present, the gene map of American mink has expanded to 127 loci.     

Effects of Dietary Iodine and Selenium on Nutrient Digestibility,Serum Thyroid Hormones,and Antioxidant Status of Liaoning Cashmere Goats

Forty-eight 2-year-old Liaoning Cashmere goats (body weight = 38.0 ± 2.94 kg) were used to investigate the effects of dietary iodine (I) and selenium (Se) supplementation on nutrient digestibility, serum thyroid hormones, and antioxidant status during the cashmere telogen period to learn more about the effects of dietary I and Se on nutrition or health status of Cashmere goats. The goats were equally divided into six groups of eight animals each that were treated with 0, 2, or 4 mg of supplemental I/kg dry matter (DM) and 0 or 1 mg of supplemental Se/kg DM in a 2 × 3 factorial arrangement of treatments. The six treatments were I₀Se₀, I₂Se₀, I₄Se₀, I₀Se₁, I₂Se₁, and I₄Se₁. The concentrations of I and Se in the basal diet were 0.67 and 0.09 mg/kg DM, respectively. The study started in March and proceeded for 45 days. Supplemental I or Se alone had no effect on nutrient digestibility and nitrogen metabolism. However, the interaction between I and Se was significant regarding the digestibility of acid detergent fiber (ADF; P < 0.05), and compared with group I₄Se₁, the digestibility of ADF was significantly increased in group I₄Se₀ (P < 0.05). Selenium supplementation did not affect serum triiodothyronine (T₃) or thyroxine (T₄) concentrations. However, the concentration of serum T₄ but not that of T₃ was significantly increased with I supplementation (P < 0.05). In addition, serum superoxide dismutase (SOD) activity was not affected (P > 0.05), but serum glutathione peroxidase (GSH-Px) activity was significantly decreased by I supplementation (P < 0.05). The antioxidant status was improved by Se supplementation, and the activities of SOD and GSH-Px were significantly increased (P < 0.05).     

The first linkage map of the American mink (Mustela vison)

Described herein, the first microsatellite linkage map for the American mink consists of 85 microsatellite markers resolved into 17 linkage groups. The map was constructed using 92 F(1) progeny from five sire families created by crossing mink with different colour types. The linkage groups ranged from 0 to 137 cM. These linkage groups were assigned to 12 of the 14 mink autosomes using a somatic cell hybrid panel. The total map covered 690 sex-averaged Kosambi units with an average marker spacing of 8 cM. This map will facilitate further genetic mapping of monogenic characters and QTL.     

The feeding ecology of mink (Mustela vison) in coastal habitat

The diet of a coast-living population of mink was investigated from the scats collected over a three-year period, and compared with information on the availability of principal prey species. Lagomorphs were the single most important prey, and predation upon them matched the abundance of rabbits as determined by monthly counts. Aquatic foraging was particularly important, with rockpool-inhabiting fish accounting for 29–1% occurrence of food items. Fish predation was more pronounced during winter months when lagomorph prey was less available. Crustacean prey, particularly the shore crab, Carcinus maenas , occurred frequently in the diet. Seabirds figured regularly in the diet; these were either taken as carrion from the strand-line or through predation on breeding colonies during the summer months.