Flushing of mink (Mustela vison): effects on energy metabolism and some blood metabolites

Abstract

Link to this article: http://journals.cambridge.org/abstract_S1357729800009061How to cite this article: R. Fink and A.-H. Tauson (1998). Flushing of mink ( Mustela vison): effects on energy metabolism and some blood metabolites. AbstractEnergy metabolism during flushing of mink (Mustela vison) in relation to a control group was studied by means of combining pooled data from balance and respiration experiments carried out in 1993 (experiment I) and 1994 (experiment II) and some blood metabolites from experiment II. The experiments, which were divided into six 1-week balance periods, started on 7 February and continued until 22 March. Flushing was performed by restricted feeding in periods 2 and 3 and refeeding in periods 4 and 5. Each balance period included a 24-h measurement of heat production by means of indirect calorimetry in open-air circuit respiration chambers. In experiment II blood samples were taken at weekly intervals and analysed for total triiodothyronine, total thyroxine, free thyroxine, glucose, insulin and fructosamine. Generally, intake of digestible nutrients and energy metabolism measurements within the flushed group were strongly influenced by period (energy supply), whereas they remained stable in the control group and differences between treatment groups over the total experiment were non-significant. The fluctuation in energy status induced by flushing did not involve major changes in body weight. Blood metabolites reflected the food intake by being fairly stable in the control group and decreasing during restriction and increasing during refeeding in the flushed group (P < 0-05). As an effect of flushing the number of corpora lutea increased significantly (P < 0-05).

LH release in mink (Mustela vison). Pattern of the LH surge and effect of metabolic status

“…Period effects were significant for thyroid hormones and IGF-1 and with insulin there was only a tendency for them; concentrations decreased during restriction and increased during refeeding. These results were in good agreement with [17,18].…”

“…Moreover, limited data have indicated that flush feeding may result in a more synchronised LH release and in more distinct peaks [42], but here, sampling frequency was too limited to allow for an un-ambiguous description of the LH release pattern. Also metabolic traits such as plasma concentrations of insulin and thyroid hormones [17] as well as IGF-1 [18] have been shown to be affected by energy supply prior to the breeding season, but the response has not been related to reproductive endocrinology.…”

Influence of different planes of energy supply prior to the breeding season on blood metabolites in female mink (Mustela vison)

“…The decrease and increase in animal live weights in the FLUSH group indicated that the food intake was less than required for maintenance during restriction, while the energy intake during the refeeding exceeded the requirement. These results were in agreement with calculations on substrate oxidation in animals exposed to a similar feeding regime [31] which showed a high level of fat oxidation during periods of restriction, whereas protein oxidation provided the major contribution to the total heat production when the food supply was ample, and with results by Fink and Tauson [17] showing negative values for retained energy [22] showing direct proportionality between insulin and level of food intake, and own previous results in mink [17]. [17], pig [16] and sheep [27] showing that [10], which probably was caused by the handling in connection with blood sampling (mink: B o rsting and Damgaard [ 10] and rat: Gdrtner et al [19]).…”

“…Previous studies with sheep [22] and mink [17] [34] and pigs [5]. Blood glucose is the primary energy substrate used at the cellular level, and reduced concentrations may influence body composition [26].…”

“…Results by Tauson [30] indicated that, as in for instance the red deer [24], thyroid hormones may be involved in the seasonal regulation of food intake also in the mink, and that plasma concentration of triiodothyronine (T 3 ) and thyroxine (T 4 ) [17] [8] and fructosamine was analysed by measuring formazane at 550 nm [4]. The between assay coefficients of variation were 1.6 and 3 %, respectively.…”