In order to understand the occurrence and development of Semanotus bifasciatus （Motschulsky）, a borer insect of Platycladus orientalis in parts of northern and eastern China and to improve its prediction, the develo...In order to understand the occurrence and development of Semanotus bifasciatus （Motschulsky）, a borer insect of Platycladus orientalis in parts of northern and eastern China and to improve its prediction, the developmental threshold temperature （C1） and effective accumulated temperature （K） of S. bifasciatus were determined under conditions of constant and variable temperatures. The results show that under constant temperatures the value of C1 has a range of 8.90±1.77℃and the value of K lies between 95.19±13.14 degree-day for eggs; the values for larvae are C1= 13.26±3.06℃ and the number of degree-day is K 2,885.07±187.87 degree-day; for pupae the ranges are C1 = 8.93±2.49℃ and K= 131.20±25.63 degree-day. Under the condition of ambient temperatures, the values for eggs are C1= 17.33±1.24℃ and K= 70.79±8.99 degree-day. It is suggested that S. bifasciatus adults over-winter in a state of dormancy, not at a diapause. Warm winter may accelerate the life cycle ofS. bifasciatus. Equations can be used to predict an early occurrence ofS. bifasciatus.展开更多
[ Objective] To study the effects of yeast chromium combined with probiotics on laying performance, intestinal microflora and digestive enzyme activities of laying hens. [ Method] A total of 432 healthy 40-week-old Ro...[ Objective] To study the effects of yeast chromium combined with probiotics on laying performance, intestinal microflora and digestive enzyme activities of laying hens. [ Method] A total of 432 healthy 40-week-old Roman brown laying hens were randomly divided into nine groups. Laying hens in control group were fed with basal diet, laying hens in test groups were fed with basal diet combining with different levels of yeast chromium （0,400,600 μg/kg） or probiotics （0,400,800 mg/kg）. [ Result] Yeast chromium, probiotics or yeast chromium combined with probiotics adding into feeds could significantly increased the laying rate （ P 〈 0.05 ） and significantly reduced feed-egg rate （ P 〈 0.05 ）. Joint use of yeast chromium and probiotics had significant interaction effects on laying rate and feed conversion rate（P 〈 0. 05）. Adding of yeast chromium combined with probiotics in diets could significantly increased the amount of Lactobacillus and Bifidobacterium （P 〈0.05 ） in ileum and cecum of laying hens, and significantly reduced the amount of Escherichia coli and Salmonella （P 〈0.05 ） , in addition, the activity of total protease, lipase and amylase in duodenal contents were significantly increased （ P 〈 0.05 ）. Joint use of yeast chromium and probioties had sig- nificant interaction effects on the activity of total protease, lipase and amylase in laying hens duodenal contents （ P 〈 0.05 ）. [ Conclusion ] Joint adding of 600μg/kg yeast chromium and 800 mg/kg probiotics in diets in summer had best effects on laying performance, intestinal microflora and digestive enzyme activities of laying hens.展开更多
[ Objectives ] To study the pathogenicity of rotavirns causing piglet diarrhea in Beijing area. [ Methods ] Six newborn piglets were randomly divided into two groups ： three piglets in test group and three in control...[ Objectives ] To study the pathogenicity of rotavirns causing piglet diarrhea in Beijing area. [ Methods ] Six newborn piglets were randomly divided into two groups ： three piglets in test group and three in control group. A total of 3 mL three-generation cell virus were evenly assigned to the three test piglets by both oral mode and subcutaneous injection, and the detoxification was observed. Anal swabs were collected at the 24^th, 48^th, 72^th and 96^th hours before and after the infection respectively, virus antigens were detected by RT-PCR, detoxlllcation was observed; small intestine, liver, spleen and other tissues of the 5-d-infected piglets were collected to observe the pathological changes. [ Results ] Anal swab detection showed that rotavirus could be detected in piglets at the 12^th after being in- fected, and the situation could continue to the 5^th d. Observation on tissue sections showed that piglet small intestinal epithelial cells and surrounding villi degenerated, epithelial cells became rounded, swollen; and enlarged nuclei and irregular cell margins could be observed. Degenerated cells fell off from matrix to lumen, at- rcphy villi was covered by flat epithelial cells, a small amount of cell debris could be observed in lamina propria. [ Conclusions ] The infection severity of porcine rotavirus depends on the atrophy degree and distribution of small intestinal villi. In addition, host, environment and other relevant factors also played an important role in the pathogenesis of porcine rotavirus.展开更多
文摘In order to understand the occurrence and development of Semanotus bifasciatus （Motschulsky）, a borer insect of Platycladus orientalis in parts of northern and eastern China and to improve its prediction, the developmental threshold temperature （C1） and effective accumulated temperature （K） of S. bifasciatus were determined under conditions of constant and variable temperatures. The results show that under constant temperatures the value of C1 has a range of 8.90±1.77℃and the value of K lies between 95.19±13.14 degree-day for eggs; the values for larvae are C1= 13.26±3.06℃ and the number of degree-day is K 2,885.07±187.87 degree-day; for pupae the ranges are C1 = 8.93±2.49℃ and K= 131.20±25.63 degree-day. Under the condition of ambient temperatures, the values for eggs are C1= 17.33±1.24℃ and K= 70.79±8.99 degree-day. It is suggested that S. bifasciatus adults over-winter in a state of dormancy, not at a diapause. Warm winter may accelerate the life cycle ofS. bifasciatus. Equations can be used to predict an early occurrence ofS. bifasciatus.
基金Supported by Beijing Agricultural Vocational College Project(XY-BS-12-03)Beijing Agricultural Science and Technology Project(20120108)Beijing Agricultural Vocational College Technology R&D and Demonstration Fund(XY-YF-13-18)
文摘[ Objective] To study the effects of yeast chromium combined with probiotics on laying performance, intestinal microflora and digestive enzyme activities of laying hens. [ Method] A total of 432 healthy 40-week-old Roman brown laying hens were randomly divided into nine groups. Laying hens in control group were fed with basal diet, laying hens in test groups were fed with basal diet combining with different levels of yeast chromium （0,400,600 μg/kg） or probiotics （0,400,800 mg/kg）. [ Result] Yeast chromium, probiotics or yeast chromium combined with probiotics adding into feeds could significantly increased the laying rate （ P 〈 0.05 ） and significantly reduced feed-egg rate （ P 〈 0.05 ）. Joint use of yeast chromium and probiotics had significant interaction effects on laying rate and feed conversion rate（P 〈 0. 05）. Adding of yeast chromium combined with probiotics in diets could significantly increased the amount of Lactobacillus and Bifidobacterium （P 〈0.05 ） in ileum and cecum of laying hens, and significantly reduced the amount of Escherichia coli and Salmonella （P 〈0.05 ） , in addition, the activity of total protease, lipase and amylase in duodenal contents were significantly increased （ P 〈 0.05 ）. Joint use of yeast chromium and probioties had sig- nificant interaction effects on the activity of total protease, lipase and amylase in laying hens duodenal contents （ P 〈 0.05 ）. [ Conclusion ] Joint adding of 600μg/kg yeast chromium and 800 mg/kg probiotics in diets in summer had best effects on laying performance, intestinal microflora and digestive enzyme activities of laying hens.
基金Supported by Beijing"Vegetable Basket"Science and Technology ability upgrading project&Beijing Agricultural Vocational College Project(XY-YF-16-24)
文摘[ Objectives ] To study the pathogenicity of rotavirns causing piglet diarrhea in Beijing area. [ Methods ] Six newborn piglets were randomly divided into two groups ： three piglets in test group and three in control group. A total of 3 mL three-generation cell virus were evenly assigned to the three test piglets by both oral mode and subcutaneous injection, and the detoxification was observed. Anal swabs were collected at the 24^th, 48^th, 72^th and 96^th hours before and after the infection respectively, virus antigens were detected by RT-PCR, detoxlllcation was observed; small intestine, liver, spleen and other tissues of the 5-d-infected piglets were collected to observe the pathological changes. [ Results ] Anal swab detection showed that rotavirus could be detected in piglets at the 12^th after being in- fected, and the situation could continue to the 5^th d. Observation on tissue sections showed that piglet small intestinal epithelial cells and surrounding villi degenerated, epithelial cells became rounded, swollen; and enlarged nuclei and irregular cell margins could be observed. Degenerated cells fell off from matrix to lumen, at- rcphy villi was covered by flat epithelial cells, a small amount of cell debris could be observed in lamina propria. [ Conclusions ] The infection severity of porcine rotavirus depends on the atrophy degree and distribution of small intestinal villi. In addition, host, environment and other relevant factors also played an important role in the pathogenesis of porcine rotavirus.
