Energy utilization of retrograded starch by sows

A total metabolism trial was conducted in eight adult sows to compare the energetic utilization, nitrogen balance, and passage rate of retrograded starch (RGS) with that of pregelatinized wheat starch (PWS). The starch was added at levels of 12 and 24 g/kg W-0.75 to a basal ration that covered the maintenance requirement. Each animal received all four treatment combinations in a change-over design. At the start and end of the trial all sows were fed the basal ration alone. Feeding took place twice daily. During each 3-week metabolism period a complete balance measurement was performed for all animals, with 6 daily collections of feces and urine and a 48-h gas exchange measurement in a respiration chamber. The sows' heat production and energy retention were calculated by the carbon-nitrogen balance method and the RQ method.