改善猪肉品质的营养调控研究进展

猪肉是人们的主要的蛋白来源,随着经济水平的提高,人们对猪肉品质提出了更高的要求。而猪肉品质的好坏除受到本身的遗传因素影响外,营养调控因素影响着猪肉品质的好坏,包括蛋白质和氨基酸水平、能量水平、维生素和矿物质水平以及饲料添加剂等因素,笔者就近几年国内外对影响猪肉品质的营养调控因素的研究加以综述,阐明营养调控因素对猪肉品质的影响,旨在为生产优质商品肉猪提供理论依据和思路。     

几种环保型饲料添加剂对欧洲鳗鲡消化酶活性的影响

选取健康均匀的欧洲鳗苗1000尾,分为5组,每组2个重复,分别在基础料中添加4种环保型饲料添加剂,分析了4种环保型饲料添加剂对欧洲鳗鲡消化酶活性的影响。结果表明,1号饲料添加剂对于提高欧洲鳗鲡消化酶整体效果最好,对中草药原料的配伍进行选择优化,适当添加半胱胺,能显著提高欧洲鳗鲡幼鱼消化酶活性。     

龙头企业与农户利益联结机制的比较研究——根据对四川省畜禽产业链的调查

根据对四川省畜禽龙头企业、合作社及养殖户的实地调研,发现不同的产品特点和产业发展阶段形成不同利益联结机制,这些机制具有不同的约束和激励效果,企业和农户的风险分担和利益分配关系也不同,并决定企业对原料产品质量安全水平的不同控制力。     

Body composition and tissue accretion rates of barrows fed corn-soybean meal diets or low-protein, amino acid-supplemented diets at different feeding levels

Two experiments, each with 39 high-lean-gain potential barrows, were conducted to evaluate the organ weights, body chemical composition, and tissue accretion rates of pigs fed corn-soybean meal diets (CONTROL) and low-protein diets supplemented with crystalline lysine, threonine, tryptophan, and methionine either on an ideal protein basis (IDEAL) or in a pattern similar to that of the control diet (AACON). Amino acids were added on a true ileally digestible basis. The initial and final BW were, respectively, 31.5 and 82.3 kg in Exp. 1 and 32.7 and 57.1 kg in Exp. 2, and pigs were fed for 55 and 27 d in Exp. 1 and 2, respectively. In Exp. 1, the CONTROL and IDEAL diets were offered on an ad libitum basis, or by feeding 90 or 80% of ad libitum intake. In Exp. 2, the CONTROL, IDEAL, and AACON diets were offered on an ad libitum basis, or by feeding 80% of the ad libitum intake. Three pigs were killed at the start of the experiments and three from each treatment were killed at the end of each experiment to determine body chemical composition. In both trials, the whole-body protein concentration (g/kg) and the accretion rates of protein (g/d) were greater (P < 0.05) for pigs fed the CONTROL than for pigs fed the IDEAL and AACON diets. In Exp. 1, pigs fed the CONTROL diet had a trend (P < 0.10) for greater water and lower lipid concentration and had greater (P < 0.05) water and ash accretion rates. Whole-body protein concentration was greatest (P < 0.05) in pigs fed at 80% of ad libitum, but protein, water, and ash accretion rates were greatest (P < 0.05) in pigs allowed ad libitum access to feed. In summary, pigs fed the IDEAL and the AACON diets had less protein in the body and lower protein accretion rates than pigs fed the CONTROL diet. It seems that reductions in protein deposition in pigs fed the IDEAL and AACON diets may have been due to a deficiency of one or more essential amino acids or possibly to increases in the NE for metabolic processes leading to increases in adipose tissue deposition.     

春季实行多批次滚动养蚕的情况总结

随着全球气侯的变暖,桑树生产期延长,产叶量增加;加之农村大量劳动力外出,在家养蚕的劳动力越来越少,养蚕劳动强度又大,存在着有桑不养蚕的现象.     

实施兽药GMP的现状分析及思考与对策

现状农业部规定2005年12月31日之前各兽药企业必须通过GMP认证,没通过的将被淘汰,各兽药企业纷纷积极响应。截至今年11月,全国2700多家兽药企业中共有92家企业或其部分车间通过兽药GMP验收,其中91家企业的100个GMP证书在有效期内。通过验收的企业数以每年翻番的速度增长,其中,2001年验收数相当于2000年以前的总和,2002年比2001年验收数增长了78%,2003年11月止比2002年增长了319%。具体兽药GMP企业年度递增表如图1所示。由上图可以看出,我国兽药GMP呈直线递增的良好趋势,为什么会出现上述情况?原因如下:政策推动:农业部颁布了《兽药生…     

Inhibition of porcine circovirus type 1 and type 2 production in PK-15 cells by small interfering RNAs targeting the Rep gene

Porcine circovirus type 1 (PCV1) and type 2 (PCV2) are two genotypes of porcine circovirus. Both of them are presumed to be widespread in the swine population. Currently, there is no specific treatment for their infections. RNA interference (RNAi) is a sequence-specific RNA degradation mechanism mediated by small interfering RNA (siRNA), which represents a possible therapeutic application for the treatment of viral infections. In this study, three siRNA expression plasmids (pS-RepA, pS-RepB and pS-RepC) were generated to target three different coding regions of the Rep protein (Rep) of PCV. These siRNAs were used to inhibit PCV production in a porcine kidney cell line, PK-15 cells. Our results revealed that Rep gene expression was inhibited by pS-RepA, pS-RepB and pS-RepC to different degrees. Moreover, our study also showed that the production of PCV1 and PCV2 was reduced by these siRNAs. pS-RepC, which targets the middle region of Rep gene, proved to be the most efficient siRNA for inhibition of Rep expression and viral production. Taken together, our data suggest that RNAi could be investigated as a potential treatment for PCV infection.     

不同投喂方式对革胡子鲶消化酶的影响

在（25±1）℃水温、自然光照条件下,设3种投喂方式饲养革胡子鲶（clarias leath-er）：第1种连续投喂整个试验期间不间断,第2和3种分别连续投喂3、7 d 后饥饿1 d,3种方式分别以R0（对照组）、R1/3、R1/7表示,试验周期共45 d。结果显示：R0、R1/3和R1/7组胃、后肠和肝脏中蛋白酶活性影响差异不显著,但前肠和中肠内蛋白酶活性影响存在差异(P<0.05)。R0、R1/3、R1/7组的胃、前肠、中肠、后肠和肝脏中淀粉酶影响不显著,R0、R1/3、R1/7的胃、前肠和肝脏内脂肪酶活性影响差异显著(P<0.05),而R0、R1/3、R1/7组中肠和后肠中脂肪酶活性影响差异不显著(P>0.05)。     

关于生物安全隔离区建设试点的几点思考

动物疫病区划管理是当前国际通行的动物疫病管理措施,目的是实现动物疫病控制或净化,提高动物卫生水平,促进动物、动物产品的国际贸易。2003年,世界动物卫生组织(OIE)提出了动物疫病区域化管理新模式--生物安全隔离区划,即在同一生物安全管理系统下,通过采取监测、控制和生物安全管理措施,建立并维持无一种或多种特定动物疫病状态的无疫生物安全隔离区。虽然该概念提出时间较短,但已引起了全世界范围的广泛关注,欧盟和澳大利亚、泰国等一些畜牧业发达国家都在进行积极地研究和探索。我国也在无疫示范区建设基础上,根据OIE有关标准和建议,研究制定生物安全隔离区建设和评价标准,并着手开展试点工作。     

胸膜莫肺炎放线杆菌APXIV部分基因片段的表达及纯化

参照GenBank中已发表的ApxIV基因序列,以自行分离的App DNA为模板,利用PCR方法扩增出ApxIV3'端,大小为552bp的保守基因序列.将PCR产物克隆到pMD18-T Simple Vector中,获得重组质粒pMD-ApxIV,对其重组质粒pMD-ApxIV进行BamHI、HindIII双酶切,并将酶切产物克隆到原核表达载体pET-32a(+)中,构建了重组表达质粒pET-ApxIV.将表达质粒转化至大肠杆菌BL21中,用IPTG诱导表达,通过SDS-PAGE和Western blot分析,结果表明pET-ApxIV在BL21中成功表达,并能被App阳性血清所识别,具有良好的免疫原性.表达蛋白的分子质量约为39.5KDa.利用HiTrap FF crude columns将表达的蛋白进行了纯化.