影响肉猪生长肥育的因素

1品种和类型的影响猪的品种和类型对肥育的影响很大,不同品种的猪,由于其培育条件、选择程度和生产方向不同,形成了遗传差异,即使在相同的条件下,其生长速度和生产效率也不同。一般优良早熟品种化晚熟品种增重快、省饲料、屠宰率高。品种和类型不同,胴体品质也有差异,对饲养条件要求也不同。2经济杂交的影响猪的品种和品系采用经济杂交,利用杂种优势,是提高肥育效果很有成效的措施之一。杂交效果决定于品种的配合力,由于配合力不同,各种杂交组合的杂种优势存在着很大的差异,因此为避免盲目杂交,须经配合力测定试验,筛选出最优秀的杂交组合,…     

犬细小病毒CPV-JL19株分离鉴定及遗传进化分析

为探究吉林地区犬细小病毒(CPV)的生物学特性及当前CPV流行株的遗传变异,采集吉林省长春市某动物医院疑似感染CPV病犬的肛拭子,经PCR鉴定为CPV阳性.利用F81细胞进行病毒培养,通过电镜形态学观察、血清学、分子生物学及攻毒试验等方法进行验证.结果 表明,成功分离鉴定出1株CPV,命名为CPV-JL19株;电镜下病...     

脑心肌炎增强型绿色荧光蛋白嵌合病毒的构建

携带增强型绿色荧光蛋白(Enhanced green fluorescent protein, EGFP)的脑心肌炎(Encephalomyocarditis virus, EMCV)嵌合病毒是研究该病毒体内外生物学特性的有力工具。因此,本研究基于前期构建的巨细胞病毒(Cytomegalovirus, CMV)感染性克隆,在EMCV基因组2A蛋白序列之后插入EGFP基因片段,并将重组质粒转染BHK-21细胞,获得携带EGFP的嵌合病毒。通过荧光定量PCR(real-time PCR)、间接免疫荧光(Indirect immunofluorescence assay, IFA)及半数组织细胞感染量测定(Median tissue culture infective dose, TCID₅₀)等方法对拯救病毒的基因组复制、蛋白表达及病毒粒子的感染性进行测定,结果证实嵌合病毒能够在BHK-21细胞上成功表达EGFP并产生完整的病毒粒子。然而,相较于野生型亲本拯救病毒,嵌合病毒在BHK-21细胞上的复制能力降低,并且在连续传代后逐渐失去绿色荧光信号,表明嵌合病毒中EGFP...     

以有机高粱推进高粱产业发展的对策探讨

四川省泸州市强力推进"中国白酒金三角"建设,通过大力发展有机高粱,促进了高粱产业的快速发展,助推泸州酒业发展。以有机高粱基地建设为抓手,促进新农村建设发展、促进农民增收,积极扩大高粱种植面积,增加高粱总产,提高产业效益,现就有机高粱促进高粱产业发展的现状和存在的主要问题做一简要分析,促进产业发展。     

2015—2016年度12个小麦新品系在淮北地区的生态适应性试验

为了鉴定西北农林科技大学农学院选育的12个小麦新品系在淮北地区的生态适应性,加快小麦育种进程,于2015—2016年在安徽淮北生态区域进行了12个小麦新品系的适应性及抗逆性鉴定试验.结果表明:12个小麦新品种中,有6个品种(品系)比当地对照品种济麦22增产,参试品系产量变幅在7453.5~9046.5kg/hm2,平均产量为8308.5kg/hm2;西农120、西农511表现出抗病性较好,产量三要素协调,综合表现较好.     

发酵玉米蛋白粉对育肥羊生长性能、屠宰性能及瘤胃发酵的影响

试验旨在研究添加发酵玉米蛋白粉（FCGM）替代豆粕对育肥羊生长性能、屠宰性能及瘤胃发酵的影响。选取48只体重（33.81±0.46）kg的健康小尾寒羊×澳洲白绵羊F1代雄性杂交绵羊。随机分为4组，每组12只。对照组饲喂基础日粮，试验组分别用FCGM替代试验饲粮中25%、50%、75%的豆粕。饲养全期饲粮精粗比为7:3。试验期70 d，其中预试期10 d，正试期60 d。结果表明：1～60 d,25%组平均日增重（ADG）高于对照组（P<0.05）；各试验组全期耗料增重比（F/G）均低于对照组；25%组胴体重和屠宰率最高（P<0.05）;75%组瘤胃液pH高于其他各组（P<0.05）,25%组和50%组瘤胃液氨态氮高于75%组（P<0.05）,50%和75%组丁酸浓度低于25%组和对照组（P<0.05）。可见，FCGM替代日粮中的豆粕可以提高育肥羊的生长性能和屠宰性能，促进瘤胃发酵，用25%替代量效果最佳。     

微型植物工厂环境控制参数优化试验研究

为了提高微型植物工厂内部温度分布均匀性和作物净光合速率,提出采用试验研究和CFD仿真相结合的方法对其环境控制参数进行优化设计。以生菜为例,通过多因素耦合试验,探索了温度、湿度和循环风速3种因素对生菜净光合速率和蒸腾速率的影响,并对不同风速控制策略下植物工厂内气流场和温度场进行了CFD数值仿真分析。试验结果表明:风速对生菜的净光合速率和蒸腾速率均有显著影响;微型植物工厂内采用上层低循环风速、下层高循环风速模式,有利于保证内部温度的均匀性,生菜的净光合速率也处于较高水平,有利于其生长。     

西藏推广保护性耕作面临诸多难题

正保护性耕作作为对传统耕作的一种颠覆性新技术,在全国乃至世界各地得到大面积的推广和应用,西藏实施保护性耕作技术既有其迫切性,又面临诸多技术难题。一、必要性分析西藏推行保护性耕作技术是由特定的农业生产条件和环境因素决定的。1.受冬春季节气候干燥,蒸发量较大和多大风天气的影响,西藏地表裸露,土壤风蚀很大,土壤贫瘠且沙化严重,产量低而不稳。2.西藏多年来使用大水漫灌的提灌和自流灌溉方式,和逐年加大化肥使用量的施肥方式,出现     

Effects of Lactic Acid Bacteria and Fructooligosaccharides on Growth Performance,Nutrient Digestibility and Serum Biochemical Indices of Arctic Foxes (Alopex lagopus) during Early Growth Period北大核心CSCD

This experiment was conducted to study the effects of dietary lactic acid bacteria (LAB) and fructooligosaccharides (FOS) on growth performance, nutrient digestibility and serum biochemical indices of Arctic foxes (Alopex lagopus) during early growth period. Sixty male post-litter Arctic foxes with the average body weight of (1.16±0.15) kg and at the age of (45±3) days were randomly assigned to 4 groups with 3 replicates per group and 5 foxes per replicate. The foxes were fed the following diets, respectively: basal diet (control group), basal diet+3×109 CFU / kg LAB (LAB group), basal diet+5 g / kg FOS (FOS group) and basal diet+3×109 CFU / kg LAB+5 g / kg FOS (LAB+FOS group). The experiment lasted for 30 days. The results showed as follows: 1) on the days 1 to 15, the diarrhea rate of foxes in the LAB group and LAB+FOS group was significantly lower than that in the control group and FOS group (P<0.05). On the days 16 to 30, the average daily gain of foxes in the LAB+FOS group was significantly higher than that in the control group and FOS group (P<0.05), but had no significant difference with LAB group (P>0.05); the diarrhea rate of foxes in the LAB+FOS group was significantly lower than that in the control group and FOS group (P<0.05), but had no significant difference with LAB group (P>0.05); compared with the FOS group, the feed to gain ratio of foxes in the LAB+FOS group was significantly decreased (P<0.05). 2) The dry matter digestibility of foxes in the LAB + FOS group was significantly higher than that in the control group and FOS group (P < 0.05), but had no significant difference with LAB group (P>0.05). There were no significant differences in nitrogen intake, fecal nitrogen, urine nitrogen, nitrogen deposition, net protein utilization and protein biological value among all groups (P>0.05). 3) Serum total protein (TP) content of foxes in the LAB+FOS group was significantly higher than that in the FOS group (P<0.05), but had no significant difference with control group and LAB group (P>0.05). Serum albumin (ALB) content of foxes in the LAB group was significantly higher than that in the control group and FOS group (P<0.05), but had no significant difference with LAB+ FOS group (P>0.05). Serum urea nitrogen (UN) content of foxes in the LAB+FOS group was significantly decreased compared with the control group (P < 0. 05). In conclusion, the combined supplementation of 3 × 109 CFU / kg LAB and 5 g / kg FOS in the diet is beneficial to reduce diarrhea rate, improve dry matter digestibility, improve body immune level, and promote the growth of Arctic foxes during early growth period. © 2023 Chinese Journal of Urology. All rights reserved.     

建立农业机械质量调查制度的探讨

随着我国农业机械保有量的不断增加,农业机械质量已经日益成为人们关注的热点问题.为此,依据<中华人民共和国农业机械化促进法>,以我国现阶段农业机械质量状况分析为基础,对农业机械质量调查工作和成果进行综述,从而进一步分析质量调查活动的特点以及优势,为农业机械质量调查方法研究提供必要性支持和理论依据.