PSVI-13 - Effects of raw soybeans and beta-mannanase (Hemicell™ HT) on growth performance and carcass characteristics of growing-finishing pigs

Abstract: The study objective was to evaluate the effects of using raw soybeans with or without a beta-mannanase (Hemicell™ HT, Elanco Animal Health, Greenfield, IN) on growth performance of finishing pigs. A total of 2,232 crossbred barrows and gilts were used in a 68-day study using a randomized complete block design (blocking factor = initial pen weight; avg. 69.4 kg). There were 72 pens of 31 pigs for 18 replicates per treatment, pigs were allocated to one of four treatments: 1) Control, 2) 10% raw soybeans, 3) 10% raw soybeans + 0.02% Hemicell™ HT, 4) 10% raw soybeans + 0.04% Hemicell™ HT. Pigs were offered ad libitum access to feed and water and were weighed on days 0, 14, 28, 49 (d 46 in Room 1, d 52 in Room 2), 61.5 (d 60 in Room 1, d 63 in Room 2), and 66.5 (d 65 in Room 1, d 68 in Room 2) of the study. Pigs were harvested on d 49 (heaviest 6-9 pigs per pen), d 61.5 (next heaviest 8-9 pigs per pen), and d 66.5 (remaining 12-14 pigs per pen). Trypsin inhibitor (TI) levels were lower (P < 0.0001; 1.28 vs. 3.54, 3.46, 3.87 TIU/mg) for Control vs. other treatments. Body weights on d 49, 61.5, and 66.5 were higher (P < 0.05; 120.1 vs. 116.7, 117.8, 117.6 kg, on day 49) for Control pigs compared to all other treatments. Average daily gain (ADG; 1,037 vs. 965, 982, 983 g/d, on d 49) and gain:feed (G:F; 0.360 vs. 0.325, 0.331, 0.327, on d 49) were higher (P < 0.001) for Control pigs during the first 49 days of the study (prior to first marketing event) and for the overall study duration (66.5 d) compared to all other treatments. Average daily feed intake (ADFI) was lower (P = 0.001; 2.98 vs. 3.09, 3.11, 3.13 kg/d) for Control pigs for the overall study duration compared to all other treatments. The inclusion of Hemicell™ HT tended to improve ADG (P = 0.06) in diets containing raw soybeans on d 49 and for the overall study duration (P = 0.07) by approx. 18 g/d. These results suggest that Hemicell™ HT may help ameliorate the effects of raw soybeans fed to pigs, but dose and duration may need to be adjusted based on age/weight of the pig and the inclusion of raw/under-processed soybeans.