The aim of this work was to study the effect of condensed tannins （CT） on the kinetic of gas production in vitro, on the three main species of Azorean pasture： Trifolium repens, Lotus corniculatus and Lolium perenn...The aim of this work was to study the effect of condensed tannins （CT） on the kinetic of gas production in vitro, on the three main species of Azorean pasture： Trifolium repens, Lotus corniculatus and Lolium perenne, using Quebracho extract as the source of CT, and also to calculate total tannins and condensed tannins on the species studied. Lotus corniculatus, Lolium perenne and Trifolium repens were tested in vitro with the inclusion of Quebracho extract in doses of 0%, 2.5% and 5% DM. The total content in tannins was determined in the 3 species. We have found, in comparison with standard tannic acid, that tannins exist in the flower of T. repens （0.81 equivalents of tannic acid） and in L .corniculatus （1.07 equivalents of tannic acid） but not in L .perenne （0 equivalents of tannic acid）. The concentration of condensed tannins in the 3 species was： 0.34 mg/mL for T. repens; 0.83 mg/mL for L. corniculatus and 0 mg/ml for L. perenne. We verified that a significant reduction （P 〈 0.05） of gas production happened for doses of 5% of CT in comparison with the other two concentrations： 0% and 2.5% of CT. The results of this study express a reduction of the fermentation rate, which implies a reduction of gas production, so, a reduction of methane emission to the atmosphere and an increase of exploitation of the protein by ruminants.展开更多
Background:Winter climate change including frequent freeze-thaw episodes and shallow snow cover will have major impacts on the spring regrowth of perennial crops.Non-bloating perennial forage legume species including ...Background:Winter climate change including frequent freeze-thaw episodes and shallow snow cover will have major impacts on the spring regrowth of perennial crops.Non-bloating perennial forage legume species including sainfoin,birdsfoot trefoil,red clover,and alsike clover have been bred for their adaptation to harsh winter conditions.In parallel,the selection of cold-tolerant rhizobial strains could allow earlier symbiotic nitrogen(N)fixation to hasten spring regrowth of legumes.Methods:To identify strains forming nodules rapidly and showing high N-fixing potential,60 rhizobial strains in association with four temperate legume species were evaluated over 11 weeks under spring soil temperatures for kinetics of nodule formation,nitrogenase activity,and host yield.Results:Strains differed in their capacity to form efficient nodules on legume hosts over time.Strains showing higher nitrogenase activity were arctic strain N10 with sainfoin and strain L2 with birdsfoot trefoil.For clovers,nitrogenase activity was similar for control and inoculated plants,likely due to formation of effective nodules in controls by endophyte rhizobia present in seeds.Conclusions:Selection based on nodulation kinetics at low temperature,nitrogenase activity,and yield was effective to identify performant rhizobial strains for legume crops.The use of cold-tolerant strains could help mitigate winter climatic changes.展开更多
文摘The aim of this work was to study the effect of condensed tannins （CT） on the kinetic of gas production in vitro, on the three main species of Azorean pasture： Trifolium repens, Lotus corniculatus and Lolium perenne, using Quebracho extract as the source of CT, and also to calculate total tannins and condensed tannins on the species studied. Lotus corniculatus, Lolium perenne and Trifolium repens were tested in vitro with the inclusion of Quebracho extract in doses of 0%, 2.5% and 5% DM. The total content in tannins was determined in the 3 species. We have found, in comparison with standard tannic acid, that tannins exist in the flower of T. repens （0.81 equivalents of tannic acid） and in L .corniculatus （1.07 equivalents of tannic acid） but not in L .perenne （0 equivalents of tannic acid）. The concentration of condensed tannins in the 3 species was： 0.34 mg/mL for T. repens; 0.83 mg/mL for L. corniculatus and 0 mg/ml for L. perenne. We verified that a significant reduction （P 〈 0.05） of gas production happened for doses of 5% of CT in comparison with the other two concentrations： 0% and 2.5% of CT. The results of this study express a reduction of the fermentation rate, which implies a reduction of gas production, so, a reduction of methane emission to the atmosphere and an increase of exploitation of the protein by ruminants.
文摘Background:Winter climate change including frequent freeze-thaw episodes and shallow snow cover will have major impacts on the spring regrowth of perennial crops.Non-bloating perennial forage legume species including sainfoin,birdsfoot trefoil,red clover,and alsike clover have been bred for their adaptation to harsh winter conditions.In parallel,the selection of cold-tolerant rhizobial strains could allow earlier symbiotic nitrogen(N)fixation to hasten spring regrowth of legumes.Methods:To identify strains forming nodules rapidly and showing high N-fixing potential,60 rhizobial strains in association with four temperate legume species were evaluated over 11 weeks under spring soil temperatures for kinetics of nodule formation,nitrogenase activity,and host yield.Results:Strains differed in their capacity to form efficient nodules on legume hosts over time.Strains showing higher nitrogenase activity were arctic strain N10 with sainfoin and strain L2 with birdsfoot trefoil.For clovers,nitrogenase activity was similar for control and inoculated plants,likely due to formation of effective nodules in controls by endophyte rhizobia present in seeds.Conclusions:Selection based on nodulation kinetics at low temperature,nitrogenase activity,and yield was effective to identify performant rhizobial strains for legume crops.The use of cold-tolerant strains could help mitigate winter climatic changes.
