Background During the transition period,the insufficient dry matter intake and a sharply increased in energy consumption to produce large quantities of milk,high yielding cows would enter a negative energy balance(NEB...Background During the transition period,the insufficient dry matter intake and a sharply increased in energy consumption to produce large quantities of milk,high yielding cows would enter a negative energy balance(NEB)that causes an increase in ketone bodies(KBs)and decrease in reproduction efficiency.The excess concentrations of circulating KBs,represented byβ-hydroxybutyric acid(BHBA),could lead to oxidative damage,which potentially cause injury to follicular granulosa cells(fGCs)and delayed follicular development.Sirtuin 3(Sirt3)regulates mitochondria reactive oxygen species(mitoROS)homeostasis in a beneficial manner;however,the molecular mechanisms underlying its involvement in the BHBA-induced injury of fGCs is poorly understood.The aim of this study was to explore the protection effects and underlying mechanisms of Sirt3 against BHBA overload-induced damage of fGCs.Results Our findings demonstrated that 2.4 mmol/L of BHBA stress increased the levels of mitoROS in bovine fGCs.Further investigations identified the subsequent mitochondrial dysfunction,including an increased abnormal rate of mitochondrial architecture,mitochondrial permeability transition pore(MPTP)opening,reductions in mitochondrial membrane potential(MMP)and Ca^(2+)release;these dysfunctions then triggered the caspase cascade reaction of apoptosis in fGCs.Notably,the overexpression of Sirt3 prior to treatment enhanced mitochondrial autophagy by increasing the expression levels of Beclin-1,thus preventing BHBA-induced mitochondrial oxidative stress and mitochondrial dysfunction in fGCs.Furthermore,our data suggested that the AMPK-mTOR-Beclin-1 pathway may be involved in the protective mechanism of Sirt3 against cellular injury triggered by BHBA stimulation.Conclusions These findings indicate that Sirt3 protects fGCs from BHBA-triggered injury by enhancing autophagy,attenuating oxidative stress and mitochondrial damage.This study provides new strategies to mitigate the fGCs injury caused by excessive BHBA stress in dairy cows with ketosis.展开更多
Profiles of energy metabolites and haptoglobin (Hp) in dairy cows that are transitioned from conventional to organic management in various Alberta farms were compared with those of dairy cows managed conventionally at...Profiles of energy metabolites and haptoglobin (Hp) in dairy cows that are transitioned from conventional to organic management in various Alberta farms were compared with those of dairy cows managed conventionally at the University of Alberta dairy farm. Blood samples were collected during the following periods: Dry, 0 - 30, 30 - 60, and 60 - 90 days in milk (DIM, n = 7 cows). Concentrations of metabolites were evaluated by enzymatic colorimetric methods. Concentrations of Hp were determined by bovine ELISA kits. Data were analyzed by the mixed procedures of SAS. Concentrations of NEFA and BHBA in blood were elevated (P < 0.001) 0 to 30 d, intermediate 30 to 60, and 60 to 90 d, and lower in the dry period. In addition, BHBA was higher (P < 0.0001) at all stages of lactation in conventional than organic cows (e.g. 1289.4 ± 88.6 vs. 883.6 ± 47.5 μmol/L in conventional and organic cows at 0 - 30 d, respectively). Serum concentrations of cholesterol increased with increasing DIM and returned to nadir levels during dry period and was higher (P < 0.0001) in conventional than organic cows. Low glucose concentrations were observed 0 to 30 d, levels were intermediate 30 to 60 and 60 to 90 d, and peaked during the dry period (P < 0.54) between conventional and organic cows. Lactate did not (P < 0.24) vary with DIM or day × farm type but was higher (P < 0.0001) in organic cows than in conventional cows. Serum concentrations of Hp were elevated during dry period;reached peak levels 0 to 30 d and decreased gradually with increasing days postpartum and were much higher at all periods in conventional than organic cows. Overall, concentrations of Hp were 528.1 ± 45.2 μg/mL in conventional cows vs. 261.1 ± 16.9 μg/mL in organic cows (P < 0.0001). Taken together, these data indicate that metabolic changes associated with initiation of lactation are preceded by an acute phase response in dairy cows, and that cows in organic systems seem to be healthier than cows under conventional systems. These differences might be due to differences in nutritional management in the two systems.展开更多
The objective of this study was to assess the occurrence of metabolic disorders in periparturient low milk production （〈 15 kg/d） dairy cows. Data were collected between April 2009 and April 2010 from randomly sele...The objective of this study was to assess the occurrence of metabolic disorders in periparturient low milk production （〈 15 kg/d） dairy cows. Data were collected between April 2009 and April 2010 from randomly selected Holstein crossed breed dairy cow and heifer （30 cows ＇,and 10 heifers） on faculty farm of faculty of Natural Resources Rajamangala University of Technology Isan, Skon-nakon Campus. Blood samples were collected weekly from each cow, starting 2 weeks before expected calving until 4 weeks postpartum. Serum was analyzed for NEFA and BHBA. The critical threshold for [NEFA] was defined as： 〉 0.4 mmol/L when 〈 -7 to 0 DIM, and 〉 0.7 mmol/L when 3 DIM. Postpartum sub-clinical ketosis （SK） was defined using [BHBA] 〉 14.4 mg/dl. The prevalence of elevated NEFA was 82.5%, 27.5%, 27.5% 7.5% and 7.5% in the dry period, 1st, 2nd 3rd and 5th weeks of lactation, respectively. The prevalence of SK was 12.5% at 2nd weeks of lactation. High prevalence of elevated NEFA during dry period through first 2 weeks of postpartum indicated that periparturient dairy cows suffered some degree of negative energy balance （NEB）. These resulted indicated that though, milk yield of these cows were not that high, NEB and ketosis are still major nutrient-related problems.展开更多
基金supported by the National Natural Science Foundation of China(32102549)the National Key R&D Program of Ningxia(2021BEF02023)+2 种基金the earmarked fund for CARS(CARS-36)the Agricultural Science and Technology Innovation Program(ASTIP-IAS06)the National Key R&D Program of Gansu(21YF5NJ196)。
文摘Background During the transition period,the insufficient dry matter intake and a sharply increased in energy consumption to produce large quantities of milk,high yielding cows would enter a negative energy balance(NEB)that causes an increase in ketone bodies(KBs)and decrease in reproduction efficiency.The excess concentrations of circulating KBs,represented byβ-hydroxybutyric acid(BHBA),could lead to oxidative damage,which potentially cause injury to follicular granulosa cells(fGCs)and delayed follicular development.Sirtuin 3(Sirt3)regulates mitochondria reactive oxygen species(mitoROS)homeostasis in a beneficial manner;however,the molecular mechanisms underlying its involvement in the BHBA-induced injury of fGCs is poorly understood.The aim of this study was to explore the protection effects and underlying mechanisms of Sirt3 against BHBA overload-induced damage of fGCs.Results Our findings demonstrated that 2.4 mmol/L of BHBA stress increased the levels of mitoROS in bovine fGCs.Further investigations identified the subsequent mitochondrial dysfunction,including an increased abnormal rate of mitochondrial architecture,mitochondrial permeability transition pore(MPTP)opening,reductions in mitochondrial membrane potential(MMP)and Ca^(2+)release;these dysfunctions then triggered the caspase cascade reaction of apoptosis in fGCs.Notably,the overexpression of Sirt3 prior to treatment enhanced mitochondrial autophagy by increasing the expression levels of Beclin-1,thus preventing BHBA-induced mitochondrial oxidative stress and mitochondrial dysfunction in fGCs.Furthermore,our data suggested that the AMPK-mTOR-Beclin-1 pathway may be involved in the protective mechanism of Sirt3 against cellular injury triggered by BHBA stimulation.Conclusions These findings indicate that Sirt3 protects fGCs from BHBA-triggered injury by enhancing autophagy,attenuating oxidative stress and mitochondrial damage.This study provides new strategies to mitigate the fGCs injury caused by excessive BHBA stress in dairy cows with ketosis.
文摘Profiles of energy metabolites and haptoglobin (Hp) in dairy cows that are transitioned from conventional to organic management in various Alberta farms were compared with those of dairy cows managed conventionally at the University of Alberta dairy farm. Blood samples were collected during the following periods: Dry, 0 - 30, 30 - 60, and 60 - 90 days in milk (DIM, n = 7 cows). Concentrations of metabolites were evaluated by enzymatic colorimetric methods. Concentrations of Hp were determined by bovine ELISA kits. Data were analyzed by the mixed procedures of SAS. Concentrations of NEFA and BHBA in blood were elevated (P < 0.001) 0 to 30 d, intermediate 30 to 60, and 60 to 90 d, and lower in the dry period. In addition, BHBA was higher (P < 0.0001) at all stages of lactation in conventional than organic cows (e.g. 1289.4 ± 88.6 vs. 883.6 ± 47.5 μmol/L in conventional and organic cows at 0 - 30 d, respectively). Serum concentrations of cholesterol increased with increasing DIM and returned to nadir levels during dry period and was higher (P < 0.0001) in conventional than organic cows. Low glucose concentrations were observed 0 to 30 d, levels were intermediate 30 to 60 and 60 to 90 d, and peaked during the dry period (P < 0.54) between conventional and organic cows. Lactate did not (P < 0.24) vary with DIM or day × farm type but was higher (P < 0.0001) in organic cows than in conventional cows. Serum concentrations of Hp were elevated during dry period;reached peak levels 0 to 30 d and decreased gradually with increasing days postpartum and were much higher at all periods in conventional than organic cows. Overall, concentrations of Hp were 528.1 ± 45.2 μg/mL in conventional cows vs. 261.1 ± 16.9 μg/mL in organic cows (P < 0.0001). Taken together, these data indicate that metabolic changes associated with initiation of lactation are preceded by an acute phase response in dairy cows, and that cows in organic systems seem to be healthier than cows under conventional systems. These differences might be due to differences in nutritional management in the two systems.
文摘The objective of this study was to assess the occurrence of metabolic disorders in periparturient low milk production （〈 15 kg/d） dairy cows. Data were collected between April 2009 and April 2010 from randomly selected Holstein crossed breed dairy cow and heifer （30 cows ＇,and 10 heifers） on faculty farm of faculty of Natural Resources Rajamangala University of Technology Isan, Skon-nakon Campus. Blood samples were collected weekly from each cow, starting 2 weeks before expected calving until 4 weeks postpartum. Serum was analyzed for NEFA and BHBA. The critical threshold for [NEFA] was defined as： 〉 0.4 mmol/L when 〈 -7 to 0 DIM, and 〉 0.7 mmol/L when 3 DIM. Postpartum sub-clinical ketosis （SK） was defined using [BHBA] 〉 14.4 mg/dl. The prevalence of elevated NEFA was 82.5%, 27.5%, 27.5% 7.5% and 7.5% in the dry period, 1st, 2nd 3rd and 5th weeks of lactation, respectively. The prevalence of SK was 12.5% at 2nd weeks of lactation. High prevalence of elevated NEFA during dry period through first 2 weeks of postpartum indicated that periparturient dairy cows suffered some degree of negative energy balance （NEB）. These resulted indicated that though, milk yield of these cows were not that high, NEB and ketosis are still major nutrient-related problems.
