Background: Ruminal microbes are vital to the conversion of lignocellulose-rich plant materials into nutrients for ruminants.Although protozoa play a key role in linking ruminal microbial networks,the contribution of ...Background: Ruminal microbes are vital to the conversion of lignocellulose-rich plant materials into nutrients for ruminants.Although protozoa play a key role in linking ruminal microbial networks,the contribution of protozoa to rumen fermentation remains controversial; therefore,this meta-analysis was conducted to quantitatively summarize the temporal dynamics of methanogenesis,ruminal volatile fatty acid(VFA) profiles and dietary fiber digestibility in ruminants following the elimination of protozoa(also termed defaunation).A total of 49 studies from 22 publications were evaluated.Results: The results revealed that defaunation reduced methane production and shifted ruminal VFA profiles to consist of more propionate and less acetate and butyrate,but with a reduced total VFA concentration and decreased dietary fiber digestibility.However,these effects were diminished linearly,at different rates,with time during the first few weeks after defaunation,and eventually reached relative stability.The acetate to propionate ratio and methane production were increased at 7 and 11 wk after defaunation,respectively.Conclusions: Elimination of protozoa initially shifted the rumen fermentation toward the production of more propionate and less methane,but eventually toward the production of less propionate and more methane over time.展开更多
Overhunting of mammals may negatively affect plant populations though indirect impacts on mammal-plant interactions such as herbivory. In this paper, we examined how hunting of terrestrial mammals impacts the survival...Overhunting of mammals may negatively affect plant populations though indirect impacts on mammal-plant interactions such as herbivory. In this paper, we examined how hunting of terrestrial mammals impacts the survival of seedlings and juveniles of the palm Astrocaryum gratum. To determine A. gratum seedling survivorship patterns, an experiment with seedlings in 25 × 250-m plots exclosures and different levels of mammal species presence was conducted: all mammals, only Tayassu peccari potentially a major seedling predator and no animals excluded. More than 50,600 non-adults were measured for 27 months. We replicated these treatments in three forest categories: 1) no hunting, with an intact mammal community, 2) a lightly hunted region and 3) a heavily hunted area. Seedling survivorship under natural non-experimental conditions was highest in the heavily hunted (S(T) = 0.72), lower in moderate and lowest in unhunted forests. Experiments revealed that T. peccari was the main agent of palm seedling mortality and the most important factor determining seedling and juvenile survivorship, for example they caused the 84.61% deaths of the seedlings in unhunted forests. Thus, T. peccari feeding habits can influence forest dynamics and forest structure. T. peccari was also susceptible to hunting pressure and as the main seed and seedling predator in the system, its extinction should affect the survivorship and distribution of A. gratum in forests.展开更多
China harbors a rich variety of forest types and forest-associated biodiversity, linked to both historical and contemporary environmental factors. However, being a country with a large population and rapid economic de...China harbors a rich variety of forest types and forest-associated biodiversity, linked to both historical and contemporary environmental factors. However, being a country with a large population and rapid economic development, its diverse forest is facing unprecedent challenges. The Chinese Forest Biodiversity Network （CForBio） was initiated 12 years ago to study the mainte- nance of biodiversity in China＇s forest ecosystems. In this review, we first summarize research progress in CForBio, and then give suggestions for future research. In the past 12 years, the research based on CForBio mainly focused on local ecological factors, such as environment filtering, biotic interactions and small-scale dispersal limitation. We suggest that future studies in CForBio should （1） continue research on trees, but expand more on insects, birds, mammals, microbes and other organism groups; （2） investigate the effects of widespread defaunation on forest biodiversity, structure and functioning; （3） evaluate the diverse effects of climate change on forest composition,structure and functioning; （4） include new technologies, such as remote sensing, to better monitor and study forest biodiversity change and maintenance.展开更多
3头同时装置永久性瘤胃瘘管和十二指肠双筒 T 形瘘管的成年阉公山羊,在精料型饲粮(以风干物质计,混合精料:青干草=50:50)的条件下,以二辛基磺琥珀酸钠(DSS)去除瘤胃纤毛虫后,瘤胃总脱氢酶活力(TDHA)比未处理前(对照期)增高约一倍(P<0...3头同时装置永久性瘤胃瘘管和十二指肠双筒 T 形瘘管的成年阉公山羊,在精料型饲粮(以风干物质计,混合精料:青干草=50:50)的条件下,以二辛基磺琥珀酸钠(DSS)去除瘤胃纤毛虫后,瘤胃总脱氢酶活力(TDHA)比未处理前(对照期)增高约一倍(P<0.01),瘤胃 NH_3—N、TVFA 和乙酸/丙酸比值显著下降。DSS 期与对照期比较,进入十二指肠食糜的总氮浓度升高(P<0.05),微生物氮则保持恒定,非微生物氮和非氨氮(NAN)均增加(P<0.05),表明在精料型饲粮条件下,去除瘤胃纤毛虫,降低饲料蛋白质在瘤胃中的降解,增加了到达十二指肠内的真蛋白的数量。展开更多
The regime of disturbance with natural or anthropogenic origin can lead to the destabilization or even to a mass mortality of benthic communities. Due to the heterogeneity of the disturbance there is a formation of pa...The regime of disturbance with natural or anthropogenic origin can lead to the destabilization or even to a mass mortality of benthic communities. Due to the heterogeneity of the disturbance there is a formation of patches in different stages of ecological succession. The aim of this study is to follow and describe the resilience in artificial disturbed sediment in a polluted bay in Rio de Janeiro. The sediment was collected, sterilized and placed inside corers (10 cmdiameter ×15 cmheight) in the same place where it was collected. We allocated the samples in two structures, the difference between them was that one was placed closed to the bottom and the other was placed50 cmheight. We found 2352 organisms distributed in 14 taxons. The class Polychaeta and the order Amphipoda showed the highest density in all the survey and treatments. We identified the factors influencing the scenarium: different mechanisms of dispersal, the position of the structures and life history of each group. Disturbance can be the main cause of the patch’s diversity found in estuaries and coastal areas. Because of this, monitoring of selected areas becomes an important tool to understand the regime of disturbance as a key factor structuring benthic communities in soft sediment, also suggesting a metapopulation dynamics.展开更多
The effect of tea saponins (TS) on rumen fermentation and methane emission was examined using an in vitro gas production technique named Reading Pressure Technique. Three levels of TS addition (0, 0.2, 0.4 mg/ml) were...The effect of tea saponins (TS) on rumen fermentation and methane emission was examined using an in vitro gas production technique named Reading Pressure Technique. Three levels of TS addition (0, 0.2, 0.4 mg/ml) were evaluated in the faunated and defaunated rumen fluid. Compared to the control, TS addition decreased the 24 h gas production in the faunated rumen fluid, but had a minor effect on gas yield in the defaunated rumen fluid. The TS significantly reduced methane production in vitro. In the faunated rumen fluid, 0.2 or 0.4 mg/ml TS decreased the 24 h methane emission by 12.7% or 14.0%, respectively. Rumen fluid pH value was affected neither by TS addition nor by defaunation. The TS addition had only minor effects on volatile fatty acids, but the yield and pattern of volatile fatty acids were greatly affected by defaunation. While the molar proportion of acetate was not affected by defaunation, the propionate was significantly increased and the butyrate significantly decreased. Ammonia-N concentration and microbial protein yield were influenced by TS inclusion and defaunation. Inclusion of 0.4 mg/ml TS increased the microbial protein mass by 18.4% and 13.8% and decreased the ammonia-N concentration by 8.3% and 19.6% in the faunated and defaunated rumen fluid, respectively. Protozoa counts were significantly reduced by TS inclusion. The current study demonstrated the beneficial effect of TS on methane production and rumen fermentation, and indicated that this may be due to the effect of the associated depression on protozoa counts.展开更多
基金supported by the National Key Research and Development Program of China(grant number:2017YFD0500500)
文摘Background: Ruminal microbes are vital to the conversion of lignocellulose-rich plant materials into nutrients for ruminants.Although protozoa play a key role in linking ruminal microbial networks,the contribution of protozoa to rumen fermentation remains controversial; therefore,this meta-analysis was conducted to quantitatively summarize the temporal dynamics of methanogenesis,ruminal volatile fatty acid(VFA) profiles and dietary fiber digestibility in ruminants following the elimination of protozoa(also termed defaunation).A total of 49 studies from 22 publications were evaluated.Results: The results revealed that defaunation reduced methane production and shifted ruminal VFA profiles to consist of more propionate and less acetate and butyrate,but with a reduced total VFA concentration and decreased dietary fiber digestibility.However,these effects were diminished linearly,at different rates,with time during the first few weeks after defaunation,and eventually reached relative stability.The acetate to propionate ratio and methane production were increased at 7 and 11 wk after defaunation,respectively.Conclusions: Elimination of protozoa initially shifted the rumen fermentation toward the production of more propionate and less methane,but eventually toward the production of less propionate and more methane over time.
文摘Overhunting of mammals may negatively affect plant populations though indirect impacts on mammal-plant interactions such as herbivory. In this paper, we examined how hunting of terrestrial mammals impacts the survival of seedlings and juveniles of the palm Astrocaryum gratum. To determine A. gratum seedling survivorship patterns, an experiment with seedlings in 25 × 250-m plots exclosures and different levels of mammal species presence was conducted: all mammals, only Tayassu peccari potentially a major seedling predator and no animals excluded. More than 50,600 non-adults were measured for 27 months. We replicated these treatments in three forest categories: 1) no hunting, with an intact mammal community, 2) a lightly hunted region and 3) a heavily hunted area. Seedling survivorship under natural non-experimental conditions was highest in the heavily hunted (S(T) = 0.72), lower in moderate and lowest in unhunted forests. Experiments revealed that T. peccari was the main agent of palm seedling mortality and the most important factor determining seedling and juvenile survivorship, for example they caused the 84.61% deaths of the seedlings in unhunted forests. Thus, T. peccari feeding habits can influence forest dynamics and forest structure. T. peccari was also susceptible to hunting pressure and as the main seed and seedling predator in the system, its extinction should affect the survivorship and distribution of A. gratum in forests.
文摘China harbors a rich variety of forest types and forest-associated biodiversity, linked to both historical and contemporary environmental factors. However, being a country with a large population and rapid economic development, its diverse forest is facing unprecedent challenges. The Chinese Forest Biodiversity Network （CForBio） was initiated 12 years ago to study the mainte- nance of biodiversity in China＇s forest ecosystems. In this review, we first summarize research progress in CForBio, and then give suggestions for future research. In the past 12 years, the research based on CForBio mainly focused on local ecological factors, such as environment filtering, biotic interactions and small-scale dispersal limitation. We suggest that future studies in CForBio should （1） continue research on trees, but expand more on insects, birds, mammals, microbes and other organism groups; （2） investigate the effects of widespread defaunation on forest biodiversity, structure and functioning; （3） evaluate the diverse effects of climate change on forest composition,structure and functioning; （4） include new technologies, such as remote sensing, to better monitor and study forest biodiversity change and maintenance.
文摘The regime of disturbance with natural or anthropogenic origin can lead to the destabilization or even to a mass mortality of benthic communities. Due to the heterogeneity of the disturbance there is a formation of patches in different stages of ecological succession. The aim of this study is to follow and describe the resilience in artificial disturbed sediment in a polluted bay in Rio de Janeiro. The sediment was collected, sterilized and placed inside corers (10 cmdiameter ×15 cmheight) in the same place where it was collected. We allocated the samples in two structures, the difference between them was that one was placed closed to the bottom and the other was placed50 cmheight. We found 2352 organisms distributed in 14 taxons. The class Polychaeta and the order Amphipoda showed the highest density in all the survey and treatments. We identified the factors influencing the scenarium: different mechanisms of dispersal, the position of the structures and life history of each group. Disturbance can be the main cause of the patch’s diversity found in estuaries and coastal areas. Because of this, monitoring of selected areas becomes an important tool to understand the regime of disturbance as a key factor structuring benthic communities in soft sediment, also suggesting a metapopulation dynamics.
基金Project (No. 12665/R0) supported partly by Co-ordinated ResearchProjects from Joint FAO/IAEA Division, IAEA
文摘The effect of tea saponins (TS) on rumen fermentation and methane emission was examined using an in vitro gas production technique named Reading Pressure Technique. Three levels of TS addition (0, 0.2, 0.4 mg/ml) were evaluated in the faunated and defaunated rumen fluid. Compared to the control, TS addition decreased the 24 h gas production in the faunated rumen fluid, but had a minor effect on gas yield in the defaunated rumen fluid. The TS significantly reduced methane production in vitro. In the faunated rumen fluid, 0.2 or 0.4 mg/ml TS decreased the 24 h methane emission by 12.7% or 14.0%, respectively. Rumen fluid pH value was affected neither by TS addition nor by defaunation. The TS addition had only minor effects on volatile fatty acids, but the yield and pattern of volatile fatty acids were greatly affected by defaunation. While the molar proportion of acetate was not affected by defaunation, the propionate was significantly increased and the butyrate significantly decreased. Ammonia-N concentration and microbial protein yield were influenced by TS inclusion and defaunation. Inclusion of 0.4 mg/ml TS increased the microbial protein mass by 18.4% and 13.8% and decreased the ammonia-N concentration by 8.3% and 19.6% in the faunated and defaunated rumen fluid, respectively. Protozoa counts were significantly reduced by TS inclusion. The current study demonstrated the beneficial effect of TS on methane production and rumen fermentation, and indicated that this may be due to the effect of the associated depression on protozoa counts.
