Yield and composition of milk and weight gain of nursing pigs from sows fed diets containing fructose or dextrose.

Yield and composition of milk and growth of nursing pigs in response to dietary treatment were estimated from 25 lactating sows during a 22-d period. Eight sows were fed 6 kg/d of a corn-soybean control diet (C sows). Nine were fed the control diet in which approximately 6.5 g X kg body weight (BW-1) X d-1 of carbohydrate was supplied by fructose corn syrup (F sows) and eight were fed the control diet containing equivalent carbohydrate supplied by powdered dextrose (D sows). Blood samples collected via jugular cannulae were analyzed for plasma concentrations of fructose, glucose and insulin. Concentrations of fructose and glucose from F sows were significantly higher throughout the study than that from D and C sows, while insulin concentration was approximately 2.5-fold lower. Milk yield from F sows on d 14 and 21 was significantly higher and pigs weaned on d 21 were heavier than those from D and C sows. Sows fed the diet containing fructose experienced significant BW loss during lactation. Coefficients of gross correlation across treatments showed milk yield and litter weight gain to be negatively associated with percentages of protein, lipids and total solids in milk, but positively associated with concentrations of lactose and gross energy. Nursing pig weight gain at weaning was more responsive to total yields of milk and milk nutrients than to composition. These data support the hypothesis that source of metabolizable energy (ME) affects milk yield, composition and efficiency at which the sow converts dietary nutrients into milk.