Background The environmental impact of feedlot operations is a growing concern,as cattle excrete a significant portion of feed nutrients as waste.Exogenous feed enzymes(EFE)have gained interest for their potential to ...Background The environmental impact of feedlot operations is a growing concern,as cattle excrete a significant portion of feed nutrients as waste.Exogenous feed enzymes(EFE)have gained interest for their potential to enhance feed efficiency in ruminants by improving nutrient digestion.However,EFE effects on ruminal parameters have shown inconsistencies,with limited research on nitrogen metabolism and rumen microbiome impacts.Moreover,the synergistic effects of combining different EFEs remain unclear.This study aimed to evaluate the effects of individual and combined EFE products in feedlot diets on ruminal fermentation parameters,nitrogen metabolism,and ruminal microbial communities.Ten rumen-cannulated Nellore steers[543±28.6 kg of body weight(BW)]were distributed in a replicated Latin-square design(5×5)in individual pens.Treatments included:control(CON,no EFE supplementation),amylase[AML,0.5 g/kg of diet dry matter(DM)],xylanase(FBL,0.9 g/kg DM),half dose combination(HD,0.25 g of AML+0.45 g of FBL/kg of DM),and full dose combination(FD,0.5 g of AML+0.90 g of FBL/kg of DM).The experimental period lasted 19 d and included total urine and feces collection(d 15 to 18)and rumen fluid sampling(d 19)at 0,4,8,12,and 16 h post-feeding for ammonia,volatile fatty acids(VFA),pH and microbiome analysis.Results EFE supplemented animals exhibited lower ruminal ammonia concentrations(P=0.040),and higher acetate proportions(P<0.001)compared to the control group.EFE supplementation resulted in reduced nitrogen(N)excretion in feces(P=0.049)and urine(P=0.036),contributing to improved N retention and efficiency(P=0.045).Additionally,EFE products induced shifts in various microbial taxa at family and genera levels(P≤0.10),which may be associated with the changes observed in ruminal fermentation.Conclusions Our findings demonstrate that EFE supplementation enhances nitrogen retention,reduces ruminal ammonia,and alters ruminal fermentation profiles and microbial populations in feedlot cattle.While the expected synergism between amylase and xylanase did not significantly impact rumen fermentation parameters,it did induce shifts in the rumen microbiome.These results suggest that EFE supplementation may be a promising strategy for improving nutrient utilization and potentially reducing the environmental impact of feedlot operations.展开更多
The aim of the current study was to investigate the effects of a lactic acid bacteria inoculant（Lactobacillus plantarum, LP）, fibrolytic enzyme（EN）, combination of LP and EN（LP＋EN） on fermentation quality, nutr...The aim of the current study was to investigate the effects of a lactic acid bacteria inoculant（Lactobacillus plantarum, LP）, fibrolytic enzyme（EN）, combination of LP and EN（LP＋EN） on fermentation quality, nutritive characteristics and in vitro digestibility of total mixed ration（TMR） silages containing 0, 7.5 and 15.0%（on dry matter basis） of rape（Brassica campestris L.） straw（RS）（denoted as CTMR, LTMR and MTMR, respectively）. After ensiling for 60 days, TMR silages without additives were well preserved, but MTMR had higher p H than CTMR and LTMR. There were no differences in other parameters of fermentation quality, microbial composition, nutrition and in vitro digestibility between CTMR and LTMR except for yeast and mold number and crude protein（CP） content. CTMR and LTMR silage had higher CP content, in vitro neutral detergent fiber digestibility（IVNDFD） and in vitro acid detergent fiber digestibility（IVADFD）, lower acid detergent fiber（ADF） content than MTMR silage. LP and EN decreased p H and increased dry matter（DM） recovery of TMR silages. LP＋EN improved the fermentation quality, nutritive characteristics and in vitro digestibility of TMR silages, showed by lower p H, ADF content, higher lactic acid content, in vitro dry matter digestibility（IVDMD） and IVNDFD. Therefore, It was suggested that TMR silage contained 7.5% RS on a DM basis and treated with LP＋EN can be as a useful feed for ruminant.展开更多
The supplementation of exogenous fibrolytic enzymes(EFE) to dairy cows diets could be a strategy to improve fiber degradation in the rumen which is especially important for the early lactating cows characterized by a ...The supplementation of exogenous fibrolytic enzymes(EFE) to dairy cows diets could be a strategy to improve fiber degradation in the rumen which is especially important for the early lactating cows characterized by a high milk energy output and an insufficient energy intake. The objective of this study was to examine the effects of a fibrolytic enzyme product(Roxazyme G2 Liquid, 3.8 and 3.9 mL/kg total mixed ration [TMR] DM) supplemented to a TMR on production performance and blood parameters of dairy cows during early(trial 1) and mid-lactation(trail 2). In addition, rumination activity was measured in trial 2. The nutrient digestibility of the experimental TMR was obtained by using wethers. In the digestibility trial, EFE was supplemented at a rate of 4.4 m L/kg Roxazyme G2 Liquid TMR-DM. The TMR contained 60% forage and 40% concentrate(DM basis). Twenty eight 50 ± 16 days in milk(DIM)and twenty six 136 ± 26 DIM Holstein cows were used in two 8-wk completely randomized trails,stratified by parity and milk yield level. One milliliter of the enzyme product contained primarily cellulase and xylanase activities(8,000 units endo-1,4-? glucanase, 18,000 units endo-1,3(4)-? glucanase and 26,000 units 1,4-? xylanase). No differences in digestibility of DM, OM, CP, NDF and ADF were observed(P >0.05) between the control and the EFE supplemented TMR. Addition of EFE to the TMR fed to early(trial 1) and mid-lactation cows(trial 2) did not affect daily dry matter intake(DMI), milk yield,4% fat-corrected milk, energy-corrected milk(ECM), concentration of milk fat, protein, fat-protein-quotients, somatic cell score, energy balance, and gross feed efficiency of early and mid-lactation cows(P >0.05). Mid-lactation cows(trial 2) fed with TMR enzyme showed a tendency of a slightly higher ECM yield(P = 0.09). The tested blood parameters were not affected by treatment in trials 1 and 2(P >0.05).Exogenous fibrolytic enzymes supplementation did not alter daily time spent ruminating in trial 2(P =0.44). In conclusion, under the conditions of this study, no positive effects of enzyme supplementation on dairy performance and health status of dairy cows during early and mid-lactation were observed.展开更多
基金supported by the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo(FAPESP,Sao Paulo,SP,BRAZIL)for the scholarship of the first authors(2019/24820-3 and 2022/00989-1)and the PDIP grant(2017/50339-5).
文摘Background The environmental impact of feedlot operations is a growing concern,as cattle excrete a significant portion of feed nutrients as waste.Exogenous feed enzymes(EFE)have gained interest for their potential to enhance feed efficiency in ruminants by improving nutrient digestion.However,EFE effects on ruminal parameters have shown inconsistencies,with limited research on nitrogen metabolism and rumen microbiome impacts.Moreover,the synergistic effects of combining different EFEs remain unclear.This study aimed to evaluate the effects of individual and combined EFE products in feedlot diets on ruminal fermentation parameters,nitrogen metabolism,and ruminal microbial communities.Ten rumen-cannulated Nellore steers[543±28.6 kg of body weight(BW)]were distributed in a replicated Latin-square design(5×5)in individual pens.Treatments included:control(CON,no EFE supplementation),amylase[AML,0.5 g/kg of diet dry matter(DM)],xylanase(FBL,0.9 g/kg DM),half dose combination(HD,0.25 g of AML+0.45 g of FBL/kg of DM),and full dose combination(FD,0.5 g of AML+0.90 g of FBL/kg of DM).The experimental period lasted 19 d and included total urine and feces collection(d 15 to 18)and rumen fluid sampling(d 19)at 0,4,8,12,and 16 h post-feeding for ammonia,volatile fatty acids(VFA),pH and microbiome analysis.Results EFE supplemented animals exhibited lower ruminal ammonia concentrations(P=0.040),and higher acetate proportions(P<0.001)compared to the control group.EFE supplementation resulted in reduced nitrogen(N)excretion in feces(P=0.049)and urine(P=0.036),contributing to improved N retention and efficiency(P=0.045).Additionally,EFE products induced shifts in various microbial taxa at family and genera levels(P≤0.10),which may be associated with the changes observed in ruminal fermentation.Conclusions Our findings demonstrate that EFE supplementation enhances nitrogen retention,reduces ruminal ammonia,and alters ruminal fermentation profiles and microbial populations in feedlot cattle.While the expected synergism between amylase and xylanase did not significantly impact rumen fermentation parameters,it did induce shifts in the rumen microbiome.These results suggest that EFE supplementation may be a promising strategy for improving nutrient utilization and potentially reducing the environmental impact of feedlot operations.
基金supported by the Natural Science Foundation of the Jiangsu Province for Young Scholars,China(BK20130694)the Specialized Research Fund for the Doctoral Program of Higher Education,China(20130097120053)+1 种基金the National Natural Science Foundation of China(31502014)the Project of Jiangsu Independent Innovation,China(CX(15)1003)
文摘The aim of the current study was to investigate the effects of a lactic acid bacteria inoculant（Lactobacillus plantarum, LP）, fibrolytic enzyme（EN）, combination of LP and EN（LP＋EN） on fermentation quality, nutritive characteristics and in vitro digestibility of total mixed ration（TMR） silages containing 0, 7.5 and 15.0%（on dry matter basis） of rape（Brassica campestris L.） straw（RS）（denoted as CTMR, LTMR and MTMR, respectively）. After ensiling for 60 days, TMR silages without additives were well preserved, but MTMR had higher p H than CTMR and LTMR. There were no differences in other parameters of fermentation quality, microbial composition, nutrition and in vitro digestibility between CTMR and LTMR except for yeast and mold number and crude protein（CP） content. CTMR and LTMR silage had higher CP content, in vitro neutral detergent fiber digestibility（IVNDFD） and in vitro acid detergent fiber digestibility（IVADFD）, lower acid detergent fiber（ADF） content than MTMR silage. LP and EN decreased p H and increased dry matter（DM） recovery of TMR silages. LP＋EN improved the fermentation quality, nutritive characteristics and in vitro digestibility of TMR silages, showed by lower p H, ADF content, higher lactic acid content, in vitro dry matter digestibility（IVDMD） and IVNDFD. Therefore, It was suggested that TMR silage contained 7.5% RS on a DM basis and treated with LP＋EN can be as a useful feed for ruminant.
文摘The supplementation of exogenous fibrolytic enzymes(EFE) to dairy cows diets could be a strategy to improve fiber degradation in the rumen which is especially important for the early lactating cows characterized by a high milk energy output and an insufficient energy intake. The objective of this study was to examine the effects of a fibrolytic enzyme product(Roxazyme G2 Liquid, 3.8 and 3.9 mL/kg total mixed ration [TMR] DM) supplemented to a TMR on production performance and blood parameters of dairy cows during early(trial 1) and mid-lactation(trail 2). In addition, rumination activity was measured in trial 2. The nutrient digestibility of the experimental TMR was obtained by using wethers. In the digestibility trial, EFE was supplemented at a rate of 4.4 m L/kg Roxazyme G2 Liquid TMR-DM. The TMR contained 60% forage and 40% concentrate(DM basis). Twenty eight 50 ± 16 days in milk(DIM)and twenty six 136 ± 26 DIM Holstein cows were used in two 8-wk completely randomized trails,stratified by parity and milk yield level. One milliliter of the enzyme product contained primarily cellulase and xylanase activities(8,000 units endo-1,4-? glucanase, 18,000 units endo-1,3(4)-? glucanase and 26,000 units 1,4-? xylanase). No differences in digestibility of DM, OM, CP, NDF and ADF were observed(P >0.05) between the control and the EFE supplemented TMR. Addition of EFE to the TMR fed to early(trial 1) and mid-lactation cows(trial 2) did not affect daily dry matter intake(DMI), milk yield,4% fat-corrected milk, energy-corrected milk(ECM), concentration of milk fat, protein, fat-protein-quotients, somatic cell score, energy balance, and gross feed efficiency of early and mid-lactation cows(P >0.05). Mid-lactation cows(trial 2) fed with TMR enzyme showed a tendency of a slightly higher ECM yield(P = 0.09). The tested blood parameters were not affected by treatment in trials 1 and 2(P >0.05).Exogenous fibrolytic enzymes supplementation did not alter daily time spent ruminating in trial 2(P =0.44). In conclusion, under the conditions of this study, no positive effects of enzyme supplementation on dairy performance and health status of dairy cows during early and mid-lactation were observed.
