猪链球菌(Streptococcus suis,SS)是一种重要的人畜共患病原体,猪链球菌2型(Streptococcus suis type 2,SS2)1954年首次在英国分离鉴定,在我国和其他养猪业发达的国家已多次流行,已成为危害我国养猪业和公共卫生安全的一个重要传染病。...猪链球菌(Streptococcus suis,SS)是一种重要的人畜共患病原体,猪链球菌2型(Streptococcus suis type 2,SS2)1954年首次在英国分离鉴定,在我国和其他养猪业发达的国家已多次流行,已成为危害我国养猪业和公共卫生安全的一个重要传染病。本研究用SS2-ZY05719株按10^(9)、10^(8)、10^(6)CFU腹腔注射途径人工感染健康的新西兰兔,3种剂量均可引起发病并死亡,新西兰兔临床症状明显,感染组平均体温升高1℃~2℃。同时分析了SS2在兔体各组织中的分布,结果显示,高剂量感染组出现明显的临床症状且快速死亡,感染剂量与发病程度有正相关性,对各试验组新西兰兔内脏组织进行检测发现,SS2主要集中在心脏、肝脏、脾脏、肺脏、肾脏和脑等组织中,不同组织器官中的细菌载量也存在着一定的差异,本文研究了SS2感染新西兰兔后的临床症状和各组织载菌量,为猪链球菌的防治及致病机理研究提供参考。展开更多
The effects of dietary lysine on production performance,serum concentrations of metabolites,growth hormone （GH）,insulin-like growth factor-I （IGF-I） and IGF-I mRNA expression in growing rabbits were examined.One h...The effects of dietary lysine on production performance,serum concentrations of metabolites,growth hormone （GH）,insulin-like growth factor-I （IGF-I） and IGF-I mRNA expression in growing rabbits were examined.One hundred weaned New Zealand rabbits were allocated to individual cages and randomly offered a diet containing 5.5 （L1）,6.5 （L2）,7.5 （L3）,8.5 （L4）,or 9.5 g （L5） lysine per kg diet.The results showed that the average daily gain （ADG） of the rabbits from L3,L4 or L5 was higher than those from L1 or L2 （P 〈 0.05）.The feed gain ratio （F/G） in the rabbits from L4 or L5 was lower than those from L1 or L2 （P 〈 0.05）.Dietary lysine did not affect serum concentrations of total protein （TP）,glucose,insulin （INS）,and growth hormone （GH） （P 〉 0.05）.The quadratic effects of lysine on the serum urea nitrogen （SUN） concentration was detected （P = 0.035）.Serum IGF-I concentrations had a trend to increase quadratically with the increasing dietary lysine （P = 0.07）.A significant correlation was found between serum IGF-I concentrations （x,ng mL-1） and ADG （y,g kg-1）： y = -0.017x2 ＋ 1.984x ＋ 20.87 （R2 = 0.8982,P = 0.003）.The relative abundance of hepatic and muscular IGF-I mRNA tended to increase with increasing dietary lysine levels （P = 0.053 and 0.082,respectively）.Providing the diets mainly consisted of corn,wheat bran and peanut vine,the most appropriate dietary lysine level for growing meat rabbits from weaning to 70 d old was found to be 8.5 g kg-1,and IGF-I may be an important factor controlling growth of weaned rabbits.展开更多
A common problem in rabbit production is the occurrence of digestive disorders just after weaning, and fiber is well known to be bcncficiai for rabbit gastrointestinal health. In order to test the hypothesis that w...A common problem in rabbit production is the occurrence of digestive disorders just after weaning, and fiber is well known to be bcncficiai for rabbit gastrointestinal health. In order to test the hypothesis that whether the good points of fiber increases with its dietary content, three isoenergetic and isonitrogenous diets and ninety mixed-sex New Zealand rabbits weaned 35-d-old were used. The results can be concluded as following： （1） Average daily feed intake （ADFI） tended to increase （i〉=0.058） while average daily gain （ADG） （p=0.001） and feed conversion ratio （FCR） （p〈0.001） deteriorated with increasing dietary ADF content. The highest morbidity was observed in the rabbits fed the highest dietary ADF concentration. （2）A decreasing coefficient of total tract apparent digestibility （CTTAD） of dry matter （DM） and crude protein （CP） was obtained with the increase of dietary fiber level （p〈0.001 and =0.003）. （3） A significant negative effect of treatments on sucrase and maltase activities in the jejunum was observed （p=0.001 and 0.003）. （4） The volatile fatty acid （VFA） concentration （p=0.011） and butyric acid （% total VFA） （P=0.001） dropped while the NH3-N concentration （P〈0.001）, pH （P=0.004） and acetic acid （% total VFA） （P〈0.001） increased with increasing dietary ADF. It was concluded that high fiber level was unfavorable to the rabbits in the first two weeks after weaning.展开更多
Objective:To explore the feasibility of establishing an animal model of chronic radiationinduced lung injury.Methods:Twenty-eight New Zealand white rabbits were randomly divided into 3 groups(the right lung irradiatio...Objective:To explore the feasibility of establishing an animal model of chronic radiationinduced lung injury.Methods:Twenty-eight New Zealand white rabbits were randomly divided into 3 groups(the right lung irradiation group,the whole lung irradiation group and the control group).Animal model of radiation-induced lung injury was established b) highdoes radiotherapy in the irradiation groups,then all rabbits underwent CT and pathological examinations at 1.2.4.8.12.16 weeks,respectively after radiation.Results:Within 4 weeks of irradiation,some rabbits in the right lung irradiation group and whole lung irradiation group died. CT and pathological examinations all showed acute radiation pneumonitis.At 8-12 weeks after irradiation,CT scanning showed ground glass samples signs,patchy shadows and fibrotic stripes. Pathological examination showed the fibrosis pulmonary alveolar wall thickened obviously. Conclusions:The clinical animal model of chronic radiation-induced lung injury which corresponds to practical conditions in clinic can be successfully established.展开更多
The open reading frame （ORF） of hAPOA1 was inserted into the prokaryotic expression vector pGEX-4T-1 to construct the recombinant plasmid pGEX- 4T-I-hAPOA1, which was then transformed into Escherichia coil strain BL...The open reading frame （ORF） of hAPOA1 was inserted into the prokaryotic expression vector pGEX-4T-1 to construct the recombinant plasmid pGEX- 4T-I-hAPOA1, which was then transformed into Escherichia coil strain BL21. The expression of target fusion protein was induced with isopropyl β-D-l-thiogalacto- pyranoside （IPTG）. The purified fusion protein in inclusion bodies was used to immunize New Zealand white rabbits to prepare hAPOA1 antiserum and the antibody titer was detected with indirect enzyme-linked immunosorbent assay （ID-EL1SA）. ID-ELISA and Western Blot proved that rabbit polyclonal antibody with a high titer of 1 ： 40 000 was produced, which may bring considerable economic benefits.展开更多
In this (modest) study, we developed artificial neural network (ANN) models for predicting body weight using various independent (input) variables in eight-week old New Zealand white purebred and crossbred rabbits. Fr...In this (modest) study, we developed artificial neural network (ANN) models for predicting body weight using various independent (input) variables in eight-week old New Zealand white purebred and crossbred rabbits. From the whole data sets of similar age groups, 75 percent were used to train the neural network model and 25 percent were used to test the effectiveness of the model. Five predictor variables were used viz, breed, sex, heart girth, body length and height at wither as input variables and body weight was considered as dependent variable from the model. The ANN used was multilayer feed forward network with back propagation of error for efficient learning. Our ANN models (with R2 = 0.68 at ten thousand iterations, and R2 = 0.71 one million iterations) performed better than traditional multivariate linear regression (MLR) models (R2 = 0.66) indicating that the ANN models were able to more accurately capture how the variations in input variables explained the variations in body weight. It is concluded that ANN models are more powerful than MLR models in predicting animals’ body weight. Nonetheless, we recognize that fitting an ANN model requires more computation resources than fitting a tradition MLR model but the benefits of its accuracy outweigh any demerit from the associated computation overhead.展开更多
文摘猪链球菌(Streptococcus suis,SS)是一种重要的人畜共患病原体,猪链球菌2型(Streptococcus suis type 2,SS2)1954年首次在英国分离鉴定,在我国和其他养猪业发达的国家已多次流行,已成为危害我国养猪业和公共卫生安全的一个重要传染病。本研究用SS2-ZY05719株按10^(9)、10^(8)、10^(6)CFU腹腔注射途径人工感染健康的新西兰兔,3种剂量均可引起发病并死亡,新西兰兔临床症状明显,感染组平均体温升高1℃~2℃。同时分析了SS2在兔体各组织中的分布,结果显示,高剂量感染组出现明显的临床症状且快速死亡,感染剂量与发病程度有正相关性,对各试验组新西兰兔内脏组织进行检测发现,SS2主要集中在心脏、肝脏、脾脏、肺脏、肾脏和脑等组织中,不同组织器官中的细菌载量也存在着一定的差异,本文研究了SS2感染新西兰兔后的临床症状和各组织载菌量,为猪链球菌的防治及致病机理研究提供参考。
基金supported by the Agriculture Profession Item (3-52)by the earmarked fund for Modern Agro-Industry Technology Research System of the Ministry of Agriculture of the P.R.China (nycytx-44)
文摘The effects of dietary lysine on production performance,serum concentrations of metabolites,growth hormone （GH）,insulin-like growth factor-I （IGF-I） and IGF-I mRNA expression in growing rabbits were examined.One hundred weaned New Zealand rabbits were allocated to individual cages and randomly offered a diet containing 5.5 （L1）,6.5 （L2）,7.5 （L3）,8.5 （L4）,or 9.5 g （L5） lysine per kg diet.The results showed that the average daily gain （ADG） of the rabbits from L3,L4 or L5 was higher than those from L1 or L2 （P 〈 0.05）.The feed gain ratio （F/G） in the rabbits from L4 or L5 was lower than those from L1 or L2 （P 〈 0.05）.Dietary lysine did not affect serum concentrations of total protein （TP）,glucose,insulin （INS）,and growth hormone （GH） （P 〉 0.05）.The quadratic effects of lysine on the serum urea nitrogen （SUN） concentration was detected （P = 0.035）.Serum IGF-I concentrations had a trend to increase quadratically with the increasing dietary lysine （P = 0.07）.A significant correlation was found between serum IGF-I concentrations （x,ng mL-1） and ADG （y,g kg-1）： y = -0.017x2 ＋ 1.984x ＋ 20.87 （R2 = 0.8982,P = 0.003）.The relative abundance of hepatic and muscular IGF-I mRNA tended to increase with increasing dietary lysine levels （P = 0.053 and 0.082,respectively）.Providing the diets mainly consisted of corn,wheat bran and peanut vine,the most appropriate dietary lysine level for growing meat rabbits from weaning to 70 d old was found to be 8.5 g kg-1,and IGF-I may be an important factor controlling growth of weaned rabbits.
文摘A common problem in rabbit production is the occurrence of digestive disorders just after weaning, and fiber is well known to be bcncficiai for rabbit gastrointestinal health. In order to test the hypothesis that whether the good points of fiber increases with its dietary content, three isoenergetic and isonitrogenous diets and ninety mixed-sex New Zealand rabbits weaned 35-d-old were used. The results can be concluded as following： （1） Average daily feed intake （ADFI） tended to increase （i〉=0.058） while average daily gain （ADG） （p=0.001） and feed conversion ratio （FCR） （p〈0.001） deteriorated with increasing dietary ADF content. The highest morbidity was observed in the rabbits fed the highest dietary ADF concentration. （2）A decreasing coefficient of total tract apparent digestibility （CTTAD） of dry matter （DM） and crude protein （CP） was obtained with the increase of dietary fiber level （p〈0.001 and =0.003）. （3） A significant negative effect of treatments on sucrase and maltase activities in the jejunum was observed （p=0.001 and 0.003）. （4） The volatile fatty acid （VFA） concentration （p=0.011） and butyric acid （% total VFA） （P=0.001） dropped while the NH3-N concentration （P〈0.001）, pH （P=0.004） and acetic acid （% total VFA） （P〈0.001） increased with increasing dietary ADF. It was concluded that high fiber level was unfavorable to the rabbits in the first two weeks after weaning.
文摘Objective:To explore the feasibility of establishing an animal model of chronic radiationinduced lung injury.Methods:Twenty-eight New Zealand white rabbits were randomly divided into 3 groups(the right lung irradiation group,the whole lung irradiation group and the control group).Animal model of radiation-induced lung injury was established b) highdoes radiotherapy in the irradiation groups,then all rabbits underwent CT and pathological examinations at 1.2.4.8.12.16 weeks,respectively after radiation.Results:Within 4 weeks of irradiation,some rabbits in the right lung irradiation group and whole lung irradiation group died. CT and pathological examinations all showed acute radiation pneumonitis.At 8-12 weeks after irradiation,CT scanning showed ground glass samples signs,patchy shadows and fibrotic stripes. Pathological examination showed the fibrosis pulmonary alveolar wall thickened obviously. Conclusions:The clinical animal model of chronic radiation-induced lung injury which corresponds to practical conditions in clinic can be successfully established.
基金Supported by the Agricultural Science Independent Innovation Fund Jiangsu Province[CX(16)1326]
文摘The open reading frame （ORF） of hAPOA1 was inserted into the prokaryotic expression vector pGEX-4T-1 to construct the recombinant plasmid pGEX- 4T-I-hAPOA1, which was then transformed into Escherichia coil strain BL21. The expression of target fusion protein was induced with isopropyl β-D-l-thiogalacto- pyranoside （IPTG）. The purified fusion protein in inclusion bodies was used to immunize New Zealand white rabbits to prepare hAPOA1 antiserum and the antibody titer was detected with indirect enzyme-linked immunosorbent assay （ID-EL1SA）. ID-ELISA and Western Blot proved that rabbit polyclonal antibody with a high titer of 1 ： 40 000 was produced, which may bring considerable economic benefits.
文摘In this (modest) study, we developed artificial neural network (ANN) models for predicting body weight using various independent (input) variables in eight-week old New Zealand white purebred and crossbred rabbits. From the whole data sets of similar age groups, 75 percent were used to train the neural network model and 25 percent were used to test the effectiveness of the model. Five predictor variables were used viz, breed, sex, heart girth, body length and height at wither as input variables and body weight was considered as dependent variable from the model. The ANN used was multilayer feed forward network with back propagation of error for efficient learning. Our ANN models (with R2 = 0.68 at ten thousand iterations, and R2 = 0.71 one million iterations) performed better than traditional multivariate linear regression (MLR) models (R2 = 0.66) indicating that the ANN models were able to more accurately capture how the variations in input variables explained the variations in body weight. It is concluded that ANN models are more powerful than MLR models in predicting animals’ body weight. Nonetheless, we recognize that fitting an ANN model requires more computation resources than fitting a tradition MLR model but the benefits of its accuracy outweigh any demerit from the associated computation overhead.
