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1.
用简化寇氏法对球敌的LD50进行了测定。以1:0.8的组间剂量比测得球敌对小鼠和雏鸡口服的LD50分别为5 746mg/kg和6 088mg/kg,95%可信限分别为6 525~5 061mg/kg和6 894~5 374mg/kg,符合微毒(实际无毒)标准。  相似文献   

2.
近年来,随着我国奶牛养殖数量和规模的不断扩大,大量的粪尿作为肥料被广泛的施用在农田里,奶牛正常的生理活动产生的大量气体(CO2和CH4)也被排放到了空气中,但是反刍动物生产中排放的这些废物却对土壤、空气和水造成了日益严重的污染,其中粪、尿和气体中的碳、氮、磷、钾元素引起的环境污染问题更是不容忽视。本文就以上存在的问题综述了奶牛生产中碳、氮、磷和钾对环境的污染,并从营养和饲养管理上提出相应的减排技术措施。  相似文献   

3.
The time periods and the behavioural pattern of mink euthanized with carbon dioxide (CO2), 100% and 70%, carbon monoxide (CO), 4%, and nitrogen (N2), 100%, are described. The time between the placement of the animal in a glass box and the first symptoms of incoordination (phase I), the period of loss of consciousness (phase II), and, finally, the coma phase until cessation of respiration (phase III) using three groups each of 10 pastel male mink each were recorded. Phase I times ranged from 14 s for CO2, 31 s for N2, and 49 s for CO. In phase II, the difference was even more pronounced, being 5 s for CO2, 15 s for CO, and 45 s for N2. In phase III, the time was 58 s for N2, 134 s and 151 s for CO2 and CO respectively. Hence, the critical period from the time when the animals were placed in the glass box till unconsciousness occurred (phase I and II) was 19 s for CO2, 64 s for CO, and 76 s for N2. The total course of euthanasia was 153 s for CO2, 215 s for CO, and 134 s for N2. The following minimum times will be required before it can be judged to be safe to remove the animals: CO2 and N2: 5 min, and for CO: 6.5 min. In a supplementary experiment, involving a mixture of 70% CO2 and 30% atmospheric air, it was not possible within the allotted time to kill adult male mink.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

4.
近年来,随着我国奶牛养殖数量和规模的不断扩大,大量的粪尿作为肥料被广泛地施用在农田里,奶牛正常的生理活动产生的大量气体(CO2和CH4)也被排放到了空气中,但是反刍动物生产中排放的这些废物却对土壤、空气和水造成了日益严重的污染,其中粪、尿和气体中的碳、氮、磷、钾元素引起的环境污染问题更是不容忽视。笔者就以上存在的问题综述了奶牛生产中碳、氮、磷和钾对环境的污染,并从营养和饲养管理上提出相应的减排技术措施。  相似文献   

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6.
近年来,随着我国奶牛养殖数量和规模的不断扩大,大量的粪尿作为肥料被广泛地施用在农田里,奶牛正常的生理活动产生的大量气体(CO2和CH4)也被排放到了空气中,但是反刍动物生产中排放的这些废物却对土壤、空气和水造成了日益严重的污染,其中粪、尿和气体中的碳、氮、磷、钾元素引起的环境污染问题更是不客忽视.笔者就以上存在的问题综述了奶牛生产中碳、氮、磷和钾对环境的污染,并从营养和饲养管理上提出相应的减排技术措施.  相似文献   

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9.
A single comb Partridge Wyandotte bantam male was mated with two Indian Game bantam females to produce a double heterozygote of the linked eumelanin extension (Ml) and pea comb (P) genes. Four females so produced were mated with their sire to provide a backcross to the double recessive. Forty crossovers occurred among the 86 progeny suggesting linkage of approximately 46 units between Ml and P. The eumelanin restrictor gene (Db) had previously been shown to be linked with P, Ml and Pg by approximately 28, 10 and 17 units respectively and, furthermore, the locus of Ml had been shown to lie between the loci of Db and Pg. The locus of Db appears therefore to lie between the loci of P and Ml and hence the relative positions of the loci of the 4 genes is P, Db, Ml, Pg.  相似文献   

10.
抗CP型、NCP型牛病毒性腹泻病毒高免卵黄抗体的制备   总被引:1,自引:0,他引:1  
本研究采用致细胞病变(cytopathic,CP)型牛病毒性腹泻病毒(bovine viral diarrhea virus,BVDV)标准毒和非致细胞病变(noncytopathic,NCP)型新疆优势毒株免疫产蛋鸡,用改良PEG法提取卵黄抗体(IgY),并对提取的IgY采用SDS-PAGE检测纯度,间接ELISA检测免疫后每隔7 d的抗体效价,并测定所得抗体对NCP型BVDV的中和效价。结果表明,用该法提取的IgY纯度较高;间接ELISA结果证明,经过4次免疫后,抗CP型BVDV的效价达到1∶32000,抗NCP型BVDV的效价达到1∶40000,3个月后再次检测,卵黄抗体效价未见明显下降。最后一次免疫14 d的抗体对NCP型BVDV的中和效价达到1×10-3。  相似文献   

11.
Roper (2020) conducted a critique of the Larson et al. (2019) study of the accuracy and confidence of data collected using systematic and random sampling designs.   Roper (2020) did not provide a data set but speculated that the Larson et al. (2019) conclusions likely reflected differences in the number of plants evaluated at each plot and the low number of independent observers rather than the sample design.  Our random sampling design employed multiple randomly located quadrat locations and measured multiple plants (> 5) that were averaged within the plot to represent plot characteristics.  Data collected in this fashion fulfilled assumptions intrinsic to and necessary for statistical analysis using plot data as observations.  Thus, the statistical observations reported in the original paper are valid.  相似文献   

12.
利用鸭胚从吉林省某鸡场表现产蛋量下降,产畸形蛋,血凝抑制试验诊断为产蛋下降综合征(EDS_(76))的病鸡输卵管、子宫中分离到两株病毒(CH—1和CH—2),经血凝试验、血凝抑制试验及电镜观察,证实为鸡产蛋下降综合征病毒.  相似文献   

13.
以新城疫病毒(NDV)LaSota株为免疫原研制了3株针对NDVHN蛋白的单抗,分别命名为1E5、C3-B7和E6-F11。3株单抗与NDV不同毒株在血凝抑制试验(HI)、ELISA和病毒中和试验中的反应性不同,而同一株单抗与同一个NDV毒株在HI、ELISA以及病毒中和试验中的反应性一致。其中,单抗1E5与NDV标准株(LaSota、F48E8)、8个NDV分离株反应阳性,而与9个NDV分离株反应阴性;单抗C3-B7、E6-F11与所有NDV毒株反应均为阳性。结果表明,3株单抗均是针对HN蛋白上的中和位点,国内部分NDV流行株的HN抗原至少有1个抗原位点发生了变异。  相似文献   

14.
The population density of horn flies was evaluated in the year 1998 in the municipality of Ara?atuba, S?o Paulo Brazil, in relation to temperature and rainfall conditions. Two lots of 30 Nellore steers (Bos indicus) were used which had no insecticidal treatment and were naturally infested with horn flies. The infestations were assessed by two counting methods, i.e., the traditional estimate method and the filming method. The highest fly frequencies were recorded in spring, summer, autumn and the lowest frequencies were recorded in winter. The increase in fly number was positively correlated (P<0.05) with rainfall.  相似文献   

15.
Cryptophilharmostes mahunkai n.gen., n.sp., a remarkable Ceratocanthidae (Coleoptera: Scarabaeoidea) from the Usambara Mountains (Tanzania), is described. The morphology of the clypeus and mesoepisternum is discussed, also with reference to other Ceratocanthidae. The affinities of the genus are discussed, and within the Afrotropical fauna a group of genera formed by Philharmostes Kolbe and its allies is recognized.  相似文献   

16.
Porcine teschovirus (PTV), Porcine sapelovirus (PSV) and Enterovirus G (EV-G) have been associated with enteric, respiratory, reproductive and neurological disorders. Although Brazil is the world’s fourth largest producer and exporter of pork, no information on the occurrence of PTV, PSV and EV-G infections is available for Brazilian pig herds. This study aimed to investigate the occurrence of Porcine enteric picornavirus infections in pig farms located in three distinct geographical regions of Brazil. Forty randomly selected diarrhoeic and normal consistency faeces of suckling (n?=?22) and nursery (n?=?18) pigs from farms located in 21 distinct cities of the Southern, Southeast, and Midwest regions of Brazil were evaluated by nested-RT-PCR assays. Suckling piglets presented the expected amplicon size for PTV (158 bp) and EV-G (313 bp) in single and mixed infections in 40.9 % (9/22) of the faecal samples. PSV amplicon (212 bp) was not detected in this age group. For nursery pigs, Porcine enteric picornaviruses amplicons were present in 77.8 % (14/18) of the faecal samples. PTV and EV-G were detected in single and mixed infections, while PSV was detected only in two samples in co-infection with PTV and EV-G in this age group. The Brazilian regions evaluated presented at least two of the tested viruses. Sequencing analysis revealed high similarities to the related viruses (95.3 to 99.2 % for PTV, 94.2 to 98.5 % for PSV and 86 to 100 % for EV-G). For the first time PTV, PSV and EV-G have been molecularly detected and characterised in pig faecal samples in Brazil.  相似文献   

17.
In order to establish data and reference values for the thickness of the myocardium and the length of the left and the right ventricle of the avian heart, the hearts of 14 budgerigars (Melopsittacus undulatus), five Alisterus parrots (Alisterus s scapularis) (also known as Australian king parrot) and 10 common buzzards (Buteo buteo) of both sexes were examined according to a standard protocol. In order to compare the results of birds of different sizes all data were related to the size of the bird's body (length of the sternum) and the results of the measurements of the myocardial thickness in relation to the length of the heart. Results of different zones were compared by means of statistical methods within one species. Besides that a comparison between the different species was performed. Only minor significant differences were noted.  相似文献   

18.
In this study we investigated the effect of kefir on the levels of glutathione (GSH), malondialdehyde (MDA), nitric oxide (NO) in the liver, stomach, spleen and colon of mice with colonic aberrant crypts formed by azoxymethane (AOM). Thirty 12 weeks old Swiss Albino mice averaging 31.5 g weight were used as experimental animals. The mice were separated into 3 groups. The first group was the control group, second group was the AOM and third group was the AOM+kefir group. We applied AOM to the second and third groups. Mice were fed ad libitum by laboratory rodent chow during the experiment period. Water was given to the first and second groups and third group received only kefir diluted with water (50%). AOM was injected subcutaneously to the second and third groups for 7 weeks (two times a week, 5 mg/kg). Six weeks after the final AOM treatment the animals were sacrificed and liver, stomach, spleen and colon samples were collected from all the groups. MDA level demonstrated an increase only in stomach for the third group (p < 0.001), while an elevation was observed for all of the four organs for the second group (spleen p < 0.001, liver p < 0.001, colon p < 0.01). GSH level showed an increase in the second group at stomach (p < 0.01) and colon (p < 0.001), while in the third group, a small increase was determined only at the colon (p < 0.05). NO level increased at all of the organs in the second group (spleen, liver, colon p < 0.001, stomach p < 0.05), but only at liver and colon in the third group 3 (p < 0.001). In conclusion these results showed that kefir plays an antioxidant role.  相似文献   

19.
依据GenBank中登录的坏死梭杆菌外膜蛋白(outer membrane protein,OMP)基因序列,设计1对引物进行PCR扩增OMP片段并克隆至pET-28a中,构建原核表达重组质粒pET-28a-OMP。将pET-28a-OMP转化到大肠杆菌BL21(DE3)感受态中,表达含2个His的重组蛋白。SDS-PAGE和Western blotting分析结果表明,该重组蛋白分子质量为93 ku,为包涵体表达,具有反应原性。本试验结果为坏死梭杆菌OMP免疫机制的研究提供了基础数据。  相似文献   

20.
Three field trials were conducted over 12 months to assess the pathogenicity of Metarhizium anisopliae to parasitic stages of Rhipicephalus (Boophilus) microplus on dairy heifers under different environmental conditions. Two isolates were selected based on their high optimal growth temperature (30 degrees C), good spore production characteristics and ability to quickly kill adult engorged ticks in the laboratory. Spores were formulated in an oil emulsion and applied using a motor driven spray unit. Surface temperatures of selected animals were monitored, as were the ambient temperature and relative humidity. Unengorged ticks sampled from each animal immediately after treatment were incubated in the laboratory to assess the efficacy of the formulation and application. Egg production by engorged ticks collected in the first 3 days after treatment was monitored. Side counts of standard adult female ticks were conducted daily, before and after treatment to assess the performance of the fungus against all tick stages on the animals. In each trial the formulation rapidly caused 100% mortality in unengorged ticks that were removed from cattle and cultured in the laboratory. A significant reduction in egg production was recorded for engorged ticks collected in the 3 days post-treatment. However, there was little effect of the formulation on the survival of ticks on cattle, indicating that there is an interaction between the environment of the ticks on the cattle and the biopesticide, which reduces its efficacy against ticks.  相似文献   

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