Effect of Starter Diet and Length of Feeding Regimen on Performance and Digestive Enzyme Activity of 2-week Old Weaned Pigs

Two experiments were conducted with 2-week-old weanling pigs (avèrage initial weight 4.1 kg) to evaluate the effects of various milk product-containing diets on digestive enzyme activity and pig performance. In the first experiment, a 20% protein corn-soybean meal-rolled oats diet was compared over a 28-day period with diets containing either 25% dried whey or 15% dried skim milk. Both milk product diets, but particularly that containing dried whey, enhanced pig performance. Amylase and protease enzyme activities in the pancreas, small and large intestine contents and in the small intestine mucosa were highest for pigs fed dried whey; these enzyme activities appeared to be influenced by the higher feed consumption and gains of the pigs in this treatment group. Total lactase activity in the small intestinal mucosa and both the small and the large intestine contents was higher when either milk product diet was provided. Most of the increase in lactase activity occurred in the large intestine contents. In the second experiment, 25% dried whey and 15% dried skim milk were evaluated alone or in combination with 5% hydrolyzed corn starch and(or) 4% dried fish solubles over a 2-or a 4-week feeding period. Performance was similar with the diets containing dried whey alone or in combination with the other ingredients, and superior to performance obtained when dried skim milk was the only milk product added to the diet. Hydrolyzed corn starch or dried fish solubles had no additional effect on pig performance. When the treatment diets were fed for a second 2-week period, pigs given the diets containing milk products had greater gains than those transferred to the cereal grain diet, but gains and feed performance for the 42-day trial were similar for all groups. Initial pig weaning weight had a curvilinear effect on average daily gain during the 42-day trial. The effect of initial weight on average daily gain decreased progressively as weaning weight increased.