Effects of different and ratios on nutrient digestibility, fecal microflora, and gas emissions of growing pigs.

The objective of this study was to evaluate the effects of different mixing ratios of and in diets on nutrient digestibility, fecal microflora, and odor gas emissions of growing pigs. A total of four crossbred ([Landrace × Yorkshire] × Duroc) barrows with average body weight (BW) of 41.2 ± 0.7 kg were randomly allotted four diets over four periods in a 4 × 4 Latin square design. Treatments were as follows: Control (CON, basal diet), CON + 0.2% probiotic complex (L4S6, and at a 4:6 ratio), CON + 0.2% probiotic complex (L5S5, and at a 5:5 ratio), CON + 0.2% probiotic complex (L6S4, and at a 6:4 ratio). Dietary probiotic supplementation showed higher crude protein (CP) digestibility values and lower counts in fecal samples than the CON group ( < 0.05). There was no significant difference in NH or HS emission until day 3. The positive effect of HS and NH emissions was detected earlier with the L4S6 and L5S5 compared to the L6S4, which had a lower ratio of . Both the L4S6 and L5S5 probiotic complexes significantly decreased the fecal HS and NH emission in days 4 and 6 ( < 0.05). On day 7, all probiotic complexes decreased ( < 0.05) HS and NH emissions than the CON group. Our results agreed that the dietary supplementation of and complexes in growing pigs can significantly improve CP digestibility and reduce fecal counts, NH and HS emissions. Notably, the higher mixing ratio of in probiotic supplementation is more effective in reducing the odor of manure.