Effects of three kinds of protease on growth performance, apparent digestibility of nutrients and caecal microbial counts in weanling pigs

摘要

This experiment investigated the effects of three single kinds of protease on performance, serum parameters, apparent digestibility of nutrients and caecal microorganisms in weanling pigs. One hundred and ninety-two White x Landrace x Duroc hybrid pigs (7.51 +/- 0.81 kg) were allotted to 1 of 4 treatments for 28 days. No protease was added to the control diet and the three experimental diets were supplemented with the same proportion of 10 IU/kg of alkaline, acidic and neutral protease, respectively. The supplementation of alkaline protease increased average daily gain and reduced serum concentrations of cholesterol and triglyceride compared with the control group (P < 0.05). The three single kinds of protease supplementation decreased the levels of serum urea nitrogen and increased the serum concentration of aspartate aminotransferase (P < 0.05). The apparent digestibility of crude protein was increased by the dietary supplementation of alkaline or acidic protease compared with that of pigs in the control group (P < 0.05). Results indicate that the alkaline protease supplementation improved the performance and apparent digestibility of crude protein in weanling pigs.