Can gas exchange measurements be used for calculation of nutrient oxidation in mink (Mustela vison) exposed to short-term changes in energy supply?

Nutrient oxidation was calculated from gas exchange measurements for 6 control and 12 flush fed female mink, measured in six consecutive, one week periods. The energy supply to controls and flushed animals in periods 1 and 6 was ca 850 kJ ME/day, and during restriction and flush feeding, it was ca 450 kg ME/day and ca 1300 kJ ME/day, respectively. Over the total experimental period the energy intake was similar in both groups, but it differed significantly between periods in the flushed group. Protein, fat, and carbohydrate oxidation averaged 39, 38, and 21%, of the total heat production (HP), respectively in the control group. During restriction, protein oxidation was ca 35% of HP in flushed animals, then increasing to 55% of HP during the first period of refeeding. High values for fat oxidation were recorded during restriction because of fat mobilization and values were low when feed supply was ample. It was concluded that the calculation method was a good indicative method, but some short-comings were discussed.