title: Effects of L-tryptophan, Fructan, and Casein on Reducing Ammonia, Hydrogen Sulfide, and Skatole in Fermented Swine Manure.
abstract: The effects of daily dietary Bacillus subtilis (Bs), and adding L-tryptophan, fructan, or casein to fecal fermentation broths were investigated as means to reduce the production of noxious gas during manure fermentation caused by ammonia, hydrogen sulfide (H2S), and 3-methylindole (skatole). Eighty swine (50.0±0.5 kg) were equally apportioned to an experimental group given Bs in daily feed, or a control group without Bs. After 6 weeks, fresh manure was collected from both groups for fermentation studies using a 3×3 orthogonal array, in which tryptophan, casein, and fructan were added at various concentrations. After fermentation, the ammonia, H2S, L-tryptophan, skatole, and microflora were measured. In both groups, L-tryptophan was the principle additive increasing skatole production, with significant correlation (r = 0.9992). L-tryptophan had no effect on the production of ammonia, H2S, or skatole in animals fed Bs. In both groups, fructan was the principle additive that reduced H2S production (r = 0.9981). Fructan and Bs significantly interacted in H2S production (p = 0.014). Casein was the principle additive affecting the concentration of ammonia, only in the control group. Casein and Bs significantly interacted in ammonia production (p = 0.039). The predominant bacteria were Bacillus spp. CWBI B1434 (26%) in the control group, and Streptococcus alactolyticus AF201899 (36%) in the experimental group. In summary, daily dietary Bs reduced ammonia production during fecal fermentation. Lessening L-tryptophan and increasing fructan in the fermentation broth reduced skatole and H2S.
authors.affiliation: Institute of Animal Science and Veterinary Medicine, Shandong Provincial Academy of Agricultural Sciences, Jinan 250100, China ; Shandong Provincial Key Laboratory of Animal Disease Control and Breeding, Jinan 250100, China .
authors.forename: Q K
authors.initials: QK
authors.lastname: Sheng
authors.affiliation: Shandong Meishida Agriculture and Husbandry Technology, Jinan 251400, China .
authors.forename: Z J
authors.initials: ZJ
authors.lastname: Yang
authors.affiliation: Institute of Animal Science and Veterinary Medicine, Shandong Provincial Academy of Agricultural Sciences, Jinan 250100, China.
authors.forename: H B
authors.initials: HB
authors.lastname: Zhao
authors.affiliation: Institute of Animal Science and Veterinary Medicine, Shandong Provincial Academy of Agricultural Sciences, Jinan 250100, China.
authors.forename: X L
authors.initials: XL
authors.lastname: Wang
authors.affiliation: Institute of Animal Science and Veterinary Medicine, Shandong Provincial Academy of Agricultural Sciences, Jinan 250100, China.
authors.forename: J F
authors.initials: JF
authors.lastname: Guo
keywords: Ammonia; B. subtilis; Casein; Fructan; H2S; L-tryptophan; Skatole; Swine Manure