Urinary and plasma metabolome of farm mink (Neovison vison) after an intervention with raw or cooked poultry offal: a 1H NMR investigation.

The introduction of high amounts of cooked poultry offal in mink feed has been associated with health problems in growing mink. Cooking mink feed is a convenient way of reducing microbiological activity, but it may have a negative effect on raw material quality and animal welfare. This study investigates growth and health of mink fed raw or cooked poultry offal and describes urinary and blood plasma metabolic changes related to the feeding. A total of 65 male mink were divided in three feeding groups, two fed cooked offal and one group fed raw offal, and the plasma and urine samples were collected at 3 time points during the growth. Both bio-fluids and feed samples were measured by 1H NMR spectroscopy and resulted metabolomics data were analysed using univariate and multivariate statistical methods that revealed dominating effect of the mink growth stages and to a less extent the feeding regime. Metabolome differences in relation to low body mass index (BMI) and kidney lesions were observed in plasma. Disease and decrease in BMI was associated with high creatinine and dimethylglycine content in plasma. These molecules were also particularly indicative of the cooked feeds. Moreover, low urinary taurine levels were also associated with disease and low BMI. Individual mink appeared to show negative effects of the cooked feed diet, including impaired growth and gross pathological lesions involving the kidneys. This may be related to the absorption of essential metabolites such as amino acids and fats, necessary for mink growth, that are negatively impacted by the cooking process.

Assessment of the accuracy of quantitative urine collection in mink (Mustela vison) using osmotic pumps for continuous release of p-amino-hippuric acid and inulin.

A method is described to assess the accuracy of quantitative collection of urine in small experimental animals using implanted Alzet osmotic pumps for continuous release of specific urinary markers. The nominal pumping rate (10.00 +/- 0.15 microliters/h; mean +/- SEM) of 10 osmotic pumps was verified (9.96 +/- 0.12 microliters/h) in a 10-day in vitro assay in isotonic saline at 39.0 degrees C. Ten adult female mink (1100 +/- 34 g) had a 2-ml osmotic pump implanted intraperitoneally for 7 days while maintained in metabolic cages on a conventional mink diet. In 5 mink the pumps contained [3H]-labelled p-aminohippuric acid (PAH) only. The remaining 5 animals received a pump containing [3H]-PAH and [14C]-labelled inulin. The experiment was well tolerated by all animals. In fed animals, the amount of urine collected per day was not influenced by the osmotic pumps, whereas 24 h of fasting (water allowed) caused a dramatic fall in urinary volume. In 4 consecutive 24-h collections of urine (n = 10 animals) the recovery of [3H]-PAH was 70.8 +/- 3.6% (range: 52.0-87.2%), and urinary plus faecal water (= total) recovery of [3H]-PAH averaged 77.0 +/- 3.7% (range: 60.3%-94.3%). For [14C]-inulin (n = 5 animals) the urinary and total recoveries were 68.4 +/- 2.2% and 77.2 +/- 2.4%, respectively. In urine the 14C to 3H counts-ratio was almost identical to that of the infusion solution, indicating that metabolic decomposition of the markers was negligible. The results indicate that the daily recovery of suitable urinary markers, released by implanted osmotic pumps, provides a reproducible and valid measure of the accuracy achieved in quantitative collection of urine in mink and probably also in other animal species. Hence, this technique may be useful in future studies on animal nutrition and/or drug disposition.

Bacterial protein meal in diets for pigs and minks: comparative studies on protein turnover rate and urinary excretion of purine base derivatives.

The effect of increasing the dietary content of bacterial protein meal (BPM) on protein turnover rate, and on nucleic acid and creatinine metabolism in growing minks and pigs was investigated in two experiments. In each experiment, 16 animals were allocated to four experimental diets. The diets containing no BPM served as controls, i.e. for minks diet M1, for pigs P1; the experimental diets contained increasing levels of BPM to replace fish meal (minks) or soybean meal (pigs), so that up to 17% (P2), 20% (M2), 35% (P3), 40% (M3), 52% (P4), and 60% (M4) of digestible N was BPM derived. Protein turnover rate was measured by means of the end-product method using [15N]glycine as tracer and urinary nitrogen as end-product. In minks, protein flux, synthesis, and breakdown increased significantly with increasing dietary BPM. In pigs, diet had no observed effect on protein turnover rate. The intake of nucleic acid nitrogen (NAN) increased from 0.15 g/kg W0.75 on M1 to 0.26 g/kg W0.75 on M3 and M4 in the mink experiment, and from 0.08 g/kg W0.75 on P1 to 0.33 g/kg W0.75 on P4 in the pig experiment. Increased NAN intake led, in both experiments, to increased allantoin excretion. Analysis of species effects showed that minks excreted 1.72 mmol/ kg W0.75 of allantoin, significantly more than the 0.95 mmol/kg W0.75 excreted by pigs. In minks, approximately 96% of the excreted purine base derivatives consisted of allantoin, whereas in pigs approximately 93% did. Thus, increasing the dietary content of BPM increased protein turnover rate in minks but not in pigs, and allantoin excretion increased with increasing dietary BPM although it seemed that mink decomposed purine bases to their end-product more completely than pigs did. Collectively these data show that BPM is a suitable protein source for pigs and mink, and recorded differences between species were to a large extent due to differences in protein retention capacity and muscle mass.

IgG4 response to fur animal allergens among fur workers.

OBJECTIVE: The aim of this study was to determine whether IgG(4) antibodies to allergens in urine extracts from fur animals associated with positive prick tests to the same allergens and with the occurrence of respiratory symptoms among fur workers, especially among highly exposed fur farmers. METHODS: Among the fur workers and among their referents, IgG(4) antibodies to mink and silver fox urine were analysed in three groups; all workers with a positive skin prick test to any fur animal allergen (n=50), all workers who had reported shortness of breath or rhinitis or eye symptoms (n=159), and to a random sample of asymptomatic persons (n=178). In the two last groups none of the workers had a positive skin test to any fur animal allergen. RESULTS: The fur farmers had higher level of IgG(4) values than other groups and also had positive IgG(4) antibodies to urine extract more frequently than the other groups. Among the exposed subjects, there was a distinct overlapping of a positive skin prick test to fur urine allergens and positive IgG(4) antibodies to responding allergens. Among the fur farmers the IgG(4) levels were associated with symptoms. CONCLUSIONS: IgG(4) antibodies were shown to be a good indicator of exposure. Because of an overlapping of positive skin prick tests and IgG(4) response to the same allergens, and an association between symptoms and IgG(4) response, it is recommended that the potential role of IgG(4) antibodies as an indicator of alternative sensitisation should be further examined in prospective studies.

Diurnal variations of urinary 6-sulphatoxymelatonin in male intact or ganglionectomized mink.

The existence of the major urinary metabolite of melatonin, 6-sulphatoxymelatonin (aMT6s), was validated for mink and the 24 hr urinary excretion pattern was determined in intact and superior cervical ganglionectomized animals under different photoperiodic conditions. Within- and between-assay variations, parallelism between serially mid-night pooled urine dilutions and standard curves in aMT6s free urine of mink at 1:125 dilution and recovery of aMT6s in mid-day pooled urine at 1:125 dilution provided a good validation for the mink urinary a MT6s assay. In natural photoperiods (January, LD 9:15; April, LD 13:11) the diurnal rhythm was characterized by low aMT6s values during the day and high values at night. There were no differences in the nocturnal values measured under long- (April, 4.11 +/- 0.40 ng/hr) or short-day (January, 4.74 +/- 0.36 ng/hr) conditions. In an experimental long photoperiod (LD 15:9), the same result was obtained on the 24 hr rhythm in intact animals, but in ganglionectomized mink the nocturnal rise in aMT6s was abolished and the nocturnal values were always low (0.88 +/- 0.09 ng/hr). Our results agree with those obtained in other species concerning plasma melatonin rhythm and urinary aMT6s excretion; we thus conclude that this is an effective assay for measuring pineal activity in mink.

Comparative biochemical profiles in blood and urine of two strains of mink and changes associated with the incidence of wet belly disease.

The blood and urine biochemical profiles of two color strains of mink, Demi-Buff and Pastel, were studied. Changes associated with the incidence of wet belly disease in some of them were determined by comparison with unaffected animals. Chloride and potassium were the only blood parameters significantly different between these two strains of mink. In blood, PO2 was the only significant difference detected between wet belly affected and unaffected mink. Pastel mink excreted significantly more potassium and nitrogen in the daily urine excretion than did the Demi-Buff strain. The most significant findings were observed in the urine of mink affected with wet belly disease when compared with unaffected animals. Twenty-four hour urine excretion volume was significantly reduced in mink with wet belly disease. Chloride, ammonia, and net acid were significantly higher than normal in the urine of mink with wet belly disease.

Effects of supplemental dietary sodium chloride and restricted drinking water on mink.

Thirty-six male mink were fed diets that contained 0, 1, 2 or 4% supplemental salt (sodium chloride) and were given drinking water ad libitum for 7 d. Three mink on each diet were then placed on ad libitum, 50% ad libitum or 25% ad libitum drinking water for the next 14 d. Ad libitum water consumption was directly proportional to the salt content of the diets. Feed consumption was inversely related to the level of dietary salt, although water restriction had a greater effect in reducing feed consumption than did the supplemental salt. The clinical signs of salt toxicity-water restriction observed were increased thirst, mild dehydration, decreased feed consumption, decreased body weight, rough coat, crusty nose and eyes, irritability in the early stage, and lethargy in the later stages. In general, serum and urinary sodium and chloride ion concentrations increased with increasing dietary salt concentrations. Expressed as a percent of brain weight, liver, spleen, kidney and heart weights of mink fed supplemental salt were less than the control weights. Adrenal gland weights increased in response to water restriction. Brain sodium concentrations were not affected by salt supplementation when drinking water was provided ad libitum. However, restricting drinking water generally resulted in increased brain sodium concentrations. Mild to moderate micro- or macrovesicular vacuolar changes were observed in the livers of some mink fed each level of dietary salt, but were especially prominent in the mink restricted in drinking water.