We evaluated the effects of neutral detergent soluble fiber （NDSF） and sucrose supplementation on ruminal fermentation, microbial synthesis, and populations of ruminal cellulolytic bacteria using the rumen simulatio...We evaluated the effects of neutral detergent soluble fiber （NDSF） and sucrose supplementation on ruminal fermentation, microbial synthesis, and populations of ruminal cellulolytic bacteria using the rumen simulation technique （RUSITEC）. The experiment had a 2x2 factorial design with two dosages of sucrose, low （ca. 0.26 g d-1, low-sucrose） and high （ca. 1.01 g d-1, high-sucrose）, and two dosages of supplied NDSF, low （1.95 g d-1, Iow-NDSF） and high （2.70 g d-1, high-NDSF）. Interactions between NDSF and sucrose were detected for xylanase activity from solid fraction and apparent disappearance of neutral detergent fiber （NDF） and hemicellulose, with the lowest values observed for high-NDSF and high-sucrose treatment. Supplemental NDSF appeared to increase the molar proportion of acetate and reduce that of butyrate; however, the effects of supplemental sucrose on VFA profiles depended upon NDSF amount. There was a NDSFxsucrose interaction for the production of methane. High-NDSF fermenters had lower ammonia-N production, greater daily N flow of solid- associated microbial pellets and total microorganisms, and greater microbial synthesis efficiency compared with low- NDSF fermenters. Supplementation with NDSF resulted in an increase in 16S rDNA copies of Ruminococcusflavefaciens and a reduction in copies of Ruminococcus albus. Supplementation with sucrose tended to increase the 16S rDNA copies ofR. albus from liquid fraction, but did not affect daily total microbial N flow and cellulolytic bacterium populations from solid fraction. These data indicate that the effects of the interaction between NDSF and sugars on ruminal fermentation and fiber digestion should be taken into account in diet formulation. Ruminal fermentation and metabolism of sugars warrant further investigation.展开更多
Background: Brewers' spent grain(BSG) typically contains 20% – 29% crude protein(CP) with high concentrations of glutamine, proline and hydrophobic and non-polar amino acid, making it an ideal material for produc...Background: Brewers' spent grain(BSG) typically contains 20% – 29% crude protein(CP) with high concentrations of glutamine, proline and hydrophobic and non-polar amino acid, making it an ideal material for producing valueadded products like bioactive peptides which have antioxidant properties. For this study, protein was extracted from BSG, hydrolyzed with 1% alcalase and flavourzyme, with the generated protein hydrolysates(AlcH and FlaH)showing antioxidant activities. This study evaluated the effects of AlcH and FlaH on gas production, ruminal fermentation characteristics, nutrient disappearance, microbial protein synthesis and microbial community using an artificial rumen system(RUSITEC) fed a high-grain diet.Results: As compared to the control of grain only, supplementation of FlaH decreased(P < 0.01) disappearances of dry matter(DM), organic matter(OM), CP and starch, without affecting fibre disappearances;while AlcH had no effect on nutrient disappearance. Neither AlcH nor FlaH affected gas production or VFA profiles, however they increased(P < 0.01) NH_3-N and decreased(P < 0.01) H_2 production. Supplementation of FlaH decreased(P < 0.01)the percentage of CH_4 in total gas and dissolved-CH_4(dCH_4) in dissolved gas. Addition of monensin reduced(P < 0.01) disappearance of nutrients, improved fermentation efficiency and reduced CH_4 and H_2 emissions.Total microbial nitrogen production was decreased(P < 0.05) but the proportion of feed particle associated(FPA) bacteria was increased with FlaH and monensin supplementation. Numbers of OTUs and Shannon diversity indices of FPA microbial community were unaffected by AlcH and FlaH;whereas both indices were reduced(P < 0.05) by monensin. Taxonomic analysis revealed no effect of AlcH and FlaH on the relative abundance(RA) of bacteria at phylum level, whereas monensin reduced(P < 0.05) the RA of Firmicutes and Bacteroidetes and enhanced Proteobacteria. Supplementation of FlaH enhanced(P < 0.05) the RA of genus Prevotella, reduced Selenomonas, Shuttleworthia, Bifidobacterium and Dialister as compared to control;monensin reduced(P < 0.05) RA of genus Prevotella but enhaced Succinivibrio.Conclusions: The supplementation of FlaH in high-grain diets may potentially protect CP and starch from ruminal degradation, without adversely affecting fibre degradation and VFA profiles. It also showed promising effects on reducing CH_4 production by suppressing H_2 production. Protein enzymatic hydrolysates from BSG using flavourzyme showed potential application to high value-added bio-products.展开更多
基金supported by the National Key Technologies R&D Program of China(2012BAD12B02)the Program of International S&T Cooperation of China(2010DFB34230)the Scientific&Technological Innovation Project of Shaanxi,China(2011KTCQ02-02)
文摘We evaluated the effects of neutral detergent soluble fiber （NDSF） and sucrose supplementation on ruminal fermentation, microbial synthesis, and populations of ruminal cellulolytic bacteria using the rumen simulation technique （RUSITEC）. The experiment had a 2x2 factorial design with two dosages of sucrose, low （ca. 0.26 g d-1, low-sucrose） and high （ca. 1.01 g d-1, high-sucrose）, and two dosages of supplied NDSF, low （1.95 g d-1, Iow-NDSF） and high （2.70 g d-1, high-NDSF）. Interactions between NDSF and sucrose were detected for xylanase activity from solid fraction and apparent disappearance of neutral detergent fiber （NDF） and hemicellulose, with the lowest values observed for high-NDSF and high-sucrose treatment. Supplemental NDSF appeared to increase the molar proportion of acetate and reduce that of butyrate; however, the effects of supplemental sucrose on VFA profiles depended upon NDSF amount. There was a NDSFxsucrose interaction for the production of methane. High-NDSF fermenters had lower ammonia-N production, greater daily N flow of solid- associated microbial pellets and total microorganisms, and greater microbial synthesis efficiency compared with low- NDSF fermenters. Supplementation with NDSF resulted in an increase in 16S rDNA copies of Ruminococcusflavefaciens and a reduction in copies of Ruminococcus albus. Supplementation with sucrose tended to increase the 16S rDNA copies ofR. albus from liquid fraction, but did not affect daily total microbial N flow and cellulolytic bacterium populations from solid fraction. These data indicate that the effects of the interaction between NDSF and sugars on ruminal fermentation and fiber digestion should be taken into account in diet formulation. Ruminal fermentation and metabolism of sugars warrant further investigation.
基金financially supported by the Agriculture and Agri-Food Canada(AAFC) Growing forward program (GF2#1542)。
文摘Background: Brewers' spent grain(BSG) typically contains 20% – 29% crude protein(CP) with high concentrations of glutamine, proline and hydrophobic and non-polar amino acid, making it an ideal material for producing valueadded products like bioactive peptides which have antioxidant properties. For this study, protein was extracted from BSG, hydrolyzed with 1% alcalase and flavourzyme, with the generated protein hydrolysates(AlcH and FlaH)showing antioxidant activities. This study evaluated the effects of AlcH and FlaH on gas production, ruminal fermentation characteristics, nutrient disappearance, microbial protein synthesis and microbial community using an artificial rumen system(RUSITEC) fed a high-grain diet.Results: As compared to the control of grain only, supplementation of FlaH decreased(P < 0.01) disappearances of dry matter(DM), organic matter(OM), CP and starch, without affecting fibre disappearances;while AlcH had no effect on nutrient disappearance. Neither AlcH nor FlaH affected gas production or VFA profiles, however they increased(P < 0.01) NH_3-N and decreased(P < 0.01) H_2 production. Supplementation of FlaH decreased(P < 0.01)the percentage of CH_4 in total gas and dissolved-CH_4(dCH_4) in dissolved gas. Addition of monensin reduced(P < 0.01) disappearance of nutrients, improved fermentation efficiency and reduced CH_4 and H_2 emissions.Total microbial nitrogen production was decreased(P < 0.05) but the proportion of feed particle associated(FPA) bacteria was increased with FlaH and monensin supplementation. Numbers of OTUs and Shannon diversity indices of FPA microbial community were unaffected by AlcH and FlaH;whereas both indices were reduced(P < 0.05) by monensin. Taxonomic analysis revealed no effect of AlcH and FlaH on the relative abundance(RA) of bacteria at phylum level, whereas monensin reduced(P < 0.05) the RA of Firmicutes and Bacteroidetes and enhanced Proteobacteria. Supplementation of FlaH enhanced(P < 0.05) the RA of genus Prevotella, reduced Selenomonas, Shuttleworthia, Bifidobacterium and Dialister as compared to control;monensin reduced(P < 0.05) RA of genus Prevotella but enhaced Succinivibrio.Conclusions: The supplementation of FlaH in high-grain diets may potentially protect CP and starch from ruminal degradation, without adversely affecting fibre degradation and VFA profiles. It also showed promising effects on reducing CH_4 production by suppressing H_2 production. Protein enzymatic hydrolysates from BSG using flavourzyme showed potential application to high value-added bio-products.
