Effects of different Bacillus licheniformis and Bacillus subtilis ratios on nutrient digestibility, fecal microflora, and gas emissions of growing pigs

Abstract

The objective of this study was to evaluate the effects of different mixing ratios of Bacillus licheniformis and Bacillus subtilis 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, B. licheniformis and B. subtilis at a 4:6 ratio), CON + 0.2% probiotic complex (L5S5, B. licheniformis and B. subtilis at a 5:5 ratio), CON + 0.2% probiotic complex (L6S4, B. licheniformis and B. subtilis at a 6:4 ratio). Dietary probiotic supplementation showed higher crude protein (CP) digestibility values and lower Escherichia coli counts in fecal samples than the CON group ( p < 0.05). There was no significant difference in NH 3 or H 2 S emission until day 3. The positive effect of H 2 S and NH 3 emissions was detected earlier with the L4S6 and L5S5 compared to the L6S4, which had a lower ratio of B. subtilis . Both the L4S6 and L5S5 probiotic complexes significantly decreased the fecal H 2 S and NH 3 emission in days 4 and 6 ( p < 0.05). On day 7, all probiotic complexes decreased ( p < 0.05) H 2 S and NH 3 emissions than the CON group. Our results agreed that the dietary supplementation of Bacillus licheniformis and Bacillus subtilis complexes in growing pigs can significantly improve CP digestibility and reduce fecal E. coli counts, NH 3 and H 2 S emissions. Notably, the higher mixing ratio of Bacillus subtilis in probiotic supplementation is more effective in reducing the odor of manure.

Effect of dietary Achyranthes japonica extract on growth performance of growing pigs and absorption rate of quercetin in blood

“…In the pig industry, the major air pollutants are NH3, H2S, and total mercaptan. Ferket et al [30] found that the emission of noxious gases from animal fecal is related to intestinal microbiota, especially harmful Escherichia coli populations [30,31]. Yan et al [32] found that pigs' higher food digestibility could lower fecal noxious gas.…”

Effects of different levels of dietary crude protein on growth performance, blood profiles, diarrhea incidence, nutrient digestibility, and odor emission in weaning pigs

“…For the odor gas estimation, 500 g of fresh feces and 400 g of urine were mixed following the methods of Kim [17]. Mixtures of fecal and urine were fermented at room temperature of 35 °C for 72 hours.…”

Investigation of supplementation with a combination of fermented bean dregs and wheat bran for improving the growth performance of the sow

“…Wheat bran also contains a moderate quantity of starch that can contribute to the fermentation of the mixed product. Fermentation by Bacillus subtilis or Aspergillus oryzae can significantly enhance the relative content of crude protein [11,12]. It can degrade antigenic proteins and trypsin inhibitors in soybean protein [13].…”