The chickens studied were from a pure line of brown shell egg-type (YAFA) female grandparents of 17-week-old. Plasima very low density lipoprotein (VLDL) concentration was measured with turbidimetric assay. The experi...The chickens studied were from a pure line of brown shell egg-type (YAFA) female grandparents of 17-week-old. Plasima very low density lipoprotein (VLDL) concentration was measured with turbidimetric assay. The experiment results showed that the phenotypic correlations between 29-week or 50-week plasma VLDL concentration and egg production (EP) were positive in the early stage of laying period, but those in the latter stage were negative. Selection for low plasma VLDL concentration will decrease the EP in the early stage of laying period but increase the one in the latter stage. There was a significant negative phenotypic correlation between the age at first egg (AFE) and 18-week body weight (BW). The phenotypic correlation between 29-week plasma VLDL concentration and the AFE was negative. AFE was influenced by BW and body fatness as well. There was significant positive phenotypic correlation between plasima VLDL concentration and body weights (BWs) at the same stage in laying period and the phenotypic correlation was also positive between 29-week plasma VLDL concentration and the BW at middle stage of laying period, indicating that selection for low plasma VLDL concentration would reduce BWs at various stages to different degree.展开更多
Leucocytozoonosis was found in three layer farms in chickens with suspected fatty liver or fatty liver hemorrhagic syndrome in Korea between 2009 and 2011.These layer chicken flocks showed both mortality and decreased...Leucocytozoonosis was found in three layer farms in chickens with suspected fatty liver or fatty liver hemorrhagic syndrome in Korea between 2009 and 2011.These layer chicken flocks showed both mortality and decreased egg production for one or two weeks when they were between 59 and 82 weeks old.At the necropsy,the most prominent gross lesions were found in the liver,which was enlarged,had a fragile texture,exhibited yellowish discolorations,and had various hemorrhagic lesions.Tissue reactions associated with megaloschizonts specific for Leucocytozoon caulleryi were prominent upon microscopic examination of the liver without significant lipidosis.In addition,the ovaries and uterus were the most affected organs for Leucocytozoon caulleryi multiplication,which led to decreased egg productions.Molecular studies with formalin-fixed,paraffin-embedded tissues were performed in search of a partial region of the cytochrome b gene for hemosporidian parasites.Based on these results,the causal agent was determined to be closely related to Leucocytozoon caulleryi reported in Japan and Malaysia.In this study,we describe recently re-occurring leucocytozoonosis in layer chickens,which required histopathology for disease diagnosis.To prevent outbreaks and maintain chicken health and egg production,layer chickens need to be monitored for symptoms of leucocytozoonosis.展开更多
Background:Gut microbiota plays a key role in health,immunity,digestion,and production in layers.Factors such as environment,diet,diseases,stress,and flock management significantly affect gut microbiota;however,it is ...Background:Gut microbiota plays a key role in health,immunity,digestion,and production in layers.Factors such as environment,diet,diseases,stress,and flock management significantly affect gut microbiota;however,it is not known how potential stressors such as intramuscular injections or feed withdrawal alter the composition of gut microbiota that result in increased the shedding level of foodborne pathogens.In the current study,the effects of intramuscular corticosterone injection and feed withdrawal were evaluated to understand their role in Salmonella Typhimurium shedding and changes in the composition of gut microbiota in layers.Results:Salmonella shedding was observed for 8 weeks post-infection.There was a significant increase in Salmonella Typhimurium count after intramuscular injection and feed withdrawal.The Salmonella infected and the negative control groups showed significant differences in the abundance of different genera in gut microbiota at week 1 and up to week 7 post infection.The infected group showed a significant reduction in alpha diversity of gut microbiota.Firmicutes reduced significantly(P<0.05)after intramuscular injection,while the feed withdrawal groups did not cause any significant changes in Proteobacteria-Firmicutes ratio.Furthermore,intramuscular injection resulted in a significant change in alpha diversity of gut microbiota.Conclusions:Exposure of chicks to relatively low dose of Salmonella Typhimurium can lead to persistent shedding in pullets.The Salmonella Typhimurium infection disrupted the gut microbiota composition immediately after infection.The potential stress of intramuscular injection and feed withdrawal significantly increased the Salmonella Typhimurium count in faeces.The intramuscular injection also resulted in a significant alteration of the Proteobacteria-Firmicutes ratio,which could increase the risk of dysbiosis.展开更多
文摘The chickens studied were from a pure line of brown shell egg-type (YAFA) female grandparents of 17-week-old. Plasima very low density lipoprotein (VLDL) concentration was measured with turbidimetric assay. The experiment results showed that the phenotypic correlations between 29-week or 50-week plasma VLDL concentration and egg production (EP) were positive in the early stage of laying period, but those in the latter stage were negative. Selection for low plasma VLDL concentration will decrease the EP in the early stage of laying period but increase the one in the latter stage. There was a significant negative phenotypic correlation between the age at first egg (AFE) and 18-week body weight (BW). The phenotypic correlation between 29-week plasma VLDL concentration and the AFE was negative. AFE was influenced by BW and body fatness as well. There was significant positive phenotypic correlation between plasima VLDL concentration and body weights (BWs) at the same stage in laying period and the phenotypic correlation was also positive between 29-week plasma VLDL concentration and the BW at middle stage of laying period, indicating that selection for low plasma VLDL concentration would reduce BWs at various stages to different degree.
基金provided by the project of National Institute of Environment Research(No.2015080777)
文摘Leucocytozoonosis was found in three layer farms in chickens with suspected fatty liver or fatty liver hemorrhagic syndrome in Korea between 2009 and 2011.These layer chicken flocks showed both mortality and decreased egg production for one or two weeks when they were between 59 and 82 weeks old.At the necropsy,the most prominent gross lesions were found in the liver,which was enlarged,had a fragile texture,exhibited yellowish discolorations,and had various hemorrhagic lesions.Tissue reactions associated with megaloschizonts specific for Leucocytozoon caulleryi were prominent upon microscopic examination of the liver without significant lipidosis.In addition,the ovaries and uterus were the most affected organs for Leucocytozoon caulleryi multiplication,which led to decreased egg productions.Molecular studies with formalin-fixed,paraffin-embedded tissues were performed in search of a partial region of the cytochrome b gene for hemosporidian parasites.Based on these results,the causal agent was determined to be closely related to Leucocytozoon caulleryi reported in Japan and Malaysia.In this study,we describe recently re-occurring leucocytozoonosis in layer chickens,which required histopathology for disease diagnosis.To prevent outbreaks and maintain chicken health and egg production,layer chickens need to be monitored for symptoms of leucocytozoonosis.
基金post graduate research scholarships from the Australian Eggs and the University of Adelaide。
文摘Background:Gut microbiota plays a key role in health,immunity,digestion,and production in layers.Factors such as environment,diet,diseases,stress,and flock management significantly affect gut microbiota;however,it is not known how potential stressors such as intramuscular injections or feed withdrawal alter the composition of gut microbiota that result in increased the shedding level of foodborne pathogens.In the current study,the effects of intramuscular corticosterone injection and feed withdrawal were evaluated to understand their role in Salmonella Typhimurium shedding and changes in the composition of gut microbiota in layers.Results:Salmonella shedding was observed for 8 weeks post-infection.There was a significant increase in Salmonella Typhimurium count after intramuscular injection and feed withdrawal.The Salmonella infected and the negative control groups showed significant differences in the abundance of different genera in gut microbiota at week 1 and up to week 7 post infection.The infected group showed a significant reduction in alpha diversity of gut microbiota.Firmicutes reduced significantly(P<0.05)after intramuscular injection,while the feed withdrawal groups did not cause any significant changes in Proteobacteria-Firmicutes ratio.Furthermore,intramuscular injection resulted in a significant change in alpha diversity of gut microbiota.Conclusions:Exposure of chicks to relatively low dose of Salmonella Typhimurium can lead to persistent shedding in pullets.The Salmonella Typhimurium infection disrupted the gut microbiota composition immediately after infection.The potential stress of intramuscular injection and feed withdrawal significantly increased the Salmonella Typhimurium count in faeces.The intramuscular injection also resulted in a significant alteration of the Proteobacteria-Firmicutes ratio,which could increase the risk of dysbiosis.
