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Effects of Dietary Protease on Nutrient Digestibility of Weaned Pigs
Effects of Dietary Protease on Nutrient Digestibility of Weaned Pigs
Sunday, July 9, 2017
Exhibit Hall (Baltimore Convention Center)
This study was conducted to investigate effects of dietary protease on nutrient digestibility of weaned pigs. A total of 75 weaned pigs (initial BW = 7.06 ± 0.18 kg; 28 d old) were randomly assigned to 3 dietary treatments (5 pigs/pen; 5 replicates/treatment) in a randomized complete block design (block = BW). The dietary treatments were 1) a diet based on corn and soybean meal to meet or exceed the requirement of crude protein as a positive control (PC; CP = 24.17%), 2) a low protein diet as a negative control (NC; CP = 23.51%), and 3) NC + 0.02% protease (PRO). The protease used in this experiment was a commercial product (Ronozyme® ProAct, DSM nutrition products, Kaiseraugst, Switzerland) containing 75,000 protease units/g derived from Bacillus licheniformis. The dietary treatments did not include spray dried plasma, fishmeal, zinc oxide, and antibiotics to avoid their antibacterial or physiological effects. Pigs were fed each treatment for 6 weeks. For the last week of the experimental period, pigs were fed respective dietary treatments containing 0.2% chromic oxide as an indigestible marker. Fecal samples from 1 randomly selected pig per replicate were collected daily by rectal palpation for the last 3 days after the 4-day adjustment period. One randomly selected pig per replicate was euthanized to collect ileal digesta at the end of the experiment. Measurements were apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of dry matter, crude protein, and energy by an index method. Data were analyzed using the PROC GLM procedure of SAS. The statistical model for every measurement included dietary effect and BW as a covariate. Pigs fed PRO and PC had higher (P < 0.05) AID of dry matter (74.36 and 74.88 vs. 68.59%), crude protein (74.71 and 73.71 vs. 68.86%), and energy (77.04 and 76.64 vs. 70.72%) than those fed NC. In addition, pigs fed PRO and PC had higher (P < 0.05) ATTD of dry matter (85.12 and 85.64 vs. 83.77%) and crude protein (79.63 and 79.90 vs. 75.34%) than pigs fed NC, but there was also no difference on ATTD of energy among dietary treatments. In conclusion, the addition of protease in nursery diets with low protein level improved nutrient digestibility of weaned pigs.