边鸡肌肉生长抑制素基因5′调控区的多态性与生长性状的关联分析

本研究采用PCR-SSCP技术检测边鸡肌肉生长抑制素(MSTN)基因5′调控区的单核苷酸多态性,并与边鸡的生长性状进行关联分析。结果表明:在MSTN基因5′调控区检测到4个突变(C1346T、G1375A、A1473G和G1491A)。在6~18周龄时(10周龄除外),ST基因型个体的体重显著或极显著高于SS型(P<0.05或P<0.01)。在14~18周龄时,TT基因型个体的体重显著或极显著的高于SS型(P<0.05或P<0.01)。研究结果提示,MSTN基因可能是影响边鸡生长性状的一个主要候选基因。     

肌肉生长抑制素基因外显子3的多态性及其与边鸡繁殖性状的关联分析

本研究采用PCR-SSCP技术检测边鸡肌肉生长抑制素(myostatin,MSTN)基因外显子3的单核苷酸多态性,并与边鸡的繁殖性状进行关联分析。结果表明:在外显子3检测到3个突变(C7 552T,C7 638T,T7 661A)。对于MYOE3-2引物,FG基因型的开产日龄极显著的早于FF基因型(P<0.01),FG基因型的300日龄产蛋数极显著高于FF基因型(P<0.01)。对于MYOE3-3引物,HI基因型的开产日龄显著早于HH基因型(P<0.05)。HI基因型的300日龄产蛋数极显著高于HH基因型(P<0.01)。3个SNPs位点共形成4种单倍型组合,单倍型组合分析表明,h1h4型的开产日龄显著早于h1h1型(P<0.05),h1h4型的产蛋数显著高于h1h1型(P<0.05)。研究结果提示,MSTN基因可能是影响边鸡繁殖性状的一个主效基因或是与之存在紧密遗传连锁的一个标记。     

边鸡MSTN基因C.234位点对生长性状的遗传效应分析

采用PCR-RFLP技术检测连续2个世代边鸡群体肌肉生长抑制素基因外显子1的多态性,分析了多态位点对边鸡生长性状的遗传效应。结果表明,边鸡MSTN基因的C.234位点存在多态性,在外显子1编码区的234bp处发生G→A的碱基突变,产生了GG、GA和AA 3种基因型。关联分析表明,无论是一世代还是二世代的边鸡群体,在6~16周龄时,AA和GA基因型边鸡的体质量均显著或极显著的高于GG基因型（P〈0.05或P〈0.01）。结果提示,MSTN基因外显子1的C.234位点突变对边鸡的生长性状具有显著的遗传效应,初步推断该位点可用于边鸡生长性状的标记辅助选择。     

STAT5b基因2个SNPs位点与京海黄鸡生长和繁殖性状的关联分析

采用PCR-SSCP方法检测京海黄鸡、AA鸡、尤溪麻鸡、边鸡4个鸡品种STAT5b基因5′调控区部分序列的多态性,并分析其对京海黄鸡生长和繁殖性状的遗传效应,利用PHASE软件对2个多态位点进行单倍型分析。在5′调控区检测到C-1591T、G-250A 2个SNPs;单倍型分析产生4种单倍型H1(CG)、H2(TG)、H3(CA)、H4(TA),单倍型组合H1H4对初生重有极显著影响(P0.01);单倍型组合H3H4与8、16周龄体重存在正相关(P0.05),单倍型组合H1H2对开产蛋重有极显著影响(P0.01);单倍型组合H3H4的开产体重极显著高于其他单倍型组合(P0.01);在300日龄体重上,单倍型组合H1H1和H1H3显著高于H4H4(P0.05)。京海黄鸡STAT5b基因5′调控区的多态性对其生长和繁殖性状有一定影响,但是否可以作为影响京海黄鸡生产性状的遗传标记需进一步研究。     

鸡GH基因内含子1 MspⅠ位点多态性及其与生长及繁殖性状的相关性

以泰和乌骨鸡等6个江西地方鸡种和罗曼蛋鸡等2个商业鸡种为试验材料，采用PCR—RFLP技术，对鸡生长激素基因内含子1MspⅠ位点多态性及其与生长、繁殖性状的相关性开展研究。结果表明：（1）产蛋性能较高的品种中以C基因为主，生长较快的品种中A基因频率和C基因频率较接近，其它品种则以A基因为主；地方鸡种均以A基因为主，而外来鸡种均以C基因为主。（2）泰和乌骨鸡和万载康乐黄鸡均表现为杂合型个体有较迟的开产日龄（P〈0．05），产蛋数问均表现为差异不显著；在万载康乐黄鸡中，各基因型间开产蛋重表现为极显著差异（P〈0．01）。（3）与体重的相关分析结果显示，在宁都三黄鸡中，该位点仅对其母鸡1月龄体重影响差异极显著（P〈0．01），对公鸡及母鸡的其它各阶段影响均不显著（P〉0．05）；在万载康乐黄鸡中，8周龄体重表现为差异不显著（P〉0．05），12、18周龄时表现为差异极显著（P〈0．01）。（4）AA和BB型有较早的开产日龄，但在开产较早的鸡中并不是频率最大的基因型；在万载康乐黄鸡中，AB型有较大体重趋势，在宁都三黄鸡种中，以AA型有体重最大趋势，在生长较快的品种中它们也并不是频率最高的基因型。     

边鸡胰岛素生长因子结合蛋白-3基因外显子2MspⅠ位点对繁殖性状的遗传效应分析

本研究采用PCR-RFLP技术检测边鸡类胰岛素生长因子结合蛋白-3(insulin-like growth factor binding proteins-3,IGFBP-3)基因外显子2 MspⅠ位点的单核苷酸多态性,并与边鸡的繁殖性状进行相关分析。结果表明,在边鸡IGFBP-3基因的1087 bp处检测到1个C→T的突变,显示3种基因型(CC、CT和TT),C等位基因为优势等位基因。最小二乘分析结果表明,CT基因型的开产体重显著高于CC基因型(P<0.05)。不同基因型对其余4个繁殖性状(开产日龄、开产蛋重、300日龄产蛋数及300日龄蛋重)均无显著影响(P>0.05)。     

淮南麻黄鸡生长曲线拟合及开产性状相关分析

采用Gompertz、Logistic和von Bertalanffy 3种模型对淮南麻黄鸡1～16周龄生长曲线进行了拟合研究,同时对20周龄体重、开产日龄以及开产蛋重等性状进行了相关分析。结果表明,在3种生长曲线模型中,von Bertalanffy模型在拟合度和预测淮南麻黄鸡1～16周龄体重效果相对较好,公、母鸡的拟合度(R2)分别为0.994和0.996,极限体重分别为2 200 g和1 333 g。淮南麻黄鸡20周龄体重、开产日龄与开产蛋重均呈正相关(P<0.01)。     

欣华鸡DRD2基因多态性及其与蛋用性状的关联分析

试验旨在研究多巴胺受体D2(dopamine receptor D2,DRD2)基因多态性及其与欣华鸡蛋用性状的相关性,寻找可用于欣华鸡蛋用性状选育的分子遗传标记。应用Primer Premier 5.0软件设计4对引物,利用PCR-RFLP技术对欣华E系鸡群的473个个体进行基因型鉴定,使用SPSS 19.0软件将欣华鸡的蛋用性状与DRD2基因多态性进行关联分析。群体多态性分析结果表明,存在4个SNPs位点:A-16105G(SNP1)、G-12510T(SNP2)、G+3360A(SNP3)和T+5042C(SNP4),其中SNP1和SNP2位点符合哈代-温伯格平衡(P>0.05),且杂合度较低,但SNP3和SNP4位点显著偏离哈代-温伯格平衡(P<0.05)。关联分析表明,DRD2基因4个SNPs位点与欣华E系鸡群体蛋用性状存在关联,其中与产蛋性状关联结果:SNP1与开产日龄显著关联(P<0.05),SNP2与33周龄产蛋数、300日龄产蛋总数极显著关联(P<0.01),SNP3与开产体重(P<0.05)、300日龄产蛋总数(P<0.01)、平均连产(P<0.01)和最长连产(P<0.05)关联,SNP4与开产日龄极显著关联(P<0.01);与蛋品质关联结果:SNP1与蛋形指数(P<0.01)、蛋黄颜色(P<0.01)和哈氏单位(P<0.05)关联,SNP2与蛋黄重显著关联(P<0.05),SNP3与蛋壳强度极显著关联(P<0.01),SNP4与蛋黄重、蛋清重和哈氏单位显著关联(P<0.05)。单倍型分析发现,DRD2基因4个SNPs位点的不同单倍型组合与欣华鸡的最长连产长度呈极显著相关(P<0.01),与哈氏单位呈显著相关(P<0.05)。组织表达谱分析发现,DRD2基因主要在欣华E系鸡垂体中表达,在58周龄鸡胸肌中有较高表达,在36周龄鸡脑中有少量表达。结果表明,DRD2基因可作为候选基因辅助用于欣华E系鸡群体蛋用性状的遗传改良。     

京海黄鸡LYZ基因SNPs检测及其与生长、产蛋性能的联系

旨在探讨溶菌酶(lysozyme,LYZ)基因与生长和产蛋性能的关系。本研究以京海黄鸡育种场培育的慢速J+和常速J-两个品系F2代育种群为试验材料,对鸡LYZ基因外显子进行了SNP检测,分析了LYZ基因与生长和产蛋性能的关系。结果,在京海黄鸡LYZ基因外显子1和2上发现了3个突变位点(G111A、T1426C、C1492T);统计分析表明,AA基因型个体12、16周龄体质量显著高于GG和GA基因型个体,开产日龄小于GG和GA基因型个体(P0.05);TT基因型个体4、8周龄体质量和开产体质量显著低于其他基因型个体,而TN基因型个体4、8周龄体质量和开产体质量显著高于其他基因型个体(P0.05);不同单倍型在4～16周龄体质量和开产体质量差异显著(P0.05);群体遗传学分析表明,3个突变位点的基因型在两品系间差异显著(P≤0.05)。初步推断鸡LYZ基因可能是控制京海黄鸡生长发育的主基因或与主基因紧密连锁。     

MSTN基因外显子3的多态性及其与边鸡生长性状的关联分析

采用PCR-SSCP技术检测边鸡及2个对照鸡群体(京海黄鸡和尤溪麻鸡)肌肉生长抑制素(myostatin,MSTN)基因外显子3的单核苷酸多态性,并与边鸡的生长性状进行相关性分析。结果表明,在MSTN基因外显子3的8527—8528 bp处检测到一个TC的插入。在边鸡和京海黄鸡中只检测到2种基因型(AA和AB基因型),在尤溪麻鸡中检测到3种基因型(AA、AB和BB基因型)。在3个鸡品种中都以A等位基因为优势等位基因。最小二乘分析结果表明,边鸡2种基因型个体的6~16周龄体重均无显著差异(P>0.05)。     

Salmonella in pork cuttings in supermarkets and butchers' shops in Denmark in 2002 and 2006

The prevalence of Salmonella in fresh pork cuttings in Denmark in the years 2002 and 2006 was investigated at retail and compared with the retail supply pattern. A total of 1025 and 3473 samples were taken in 2002 from butcher's shops and supermarkets, respectively. The corresponding numbers in 2006 were 259 from butchers' shops and 628 from supermarkets. In 2002, 1.2% of all samples were positive for Salmonella; butchers' shops and supermarkets had 1.8% and 1.0% positive samples, respectively. The overall prevalence in 2006 was 4.2%, with prevalence of 8.1% and 2.6% for butchers' shops and supermarkets, respectively. Hence, increases around 3- to 5-fold were found. There was neither observed any parallel increase in Salmonella positive carcasses in Danish slaughterhouses during the study period, nor were any changes in supply routes towards slaughterhouses with higher prevalence observed, which could explain the apparent increase. We hypothesize that hygiene levels and ability to avoid cross-contamination and prevent growth of the organism, in the meat processing chain after slaughter were the most likely responsible factors. Results from this study indicate that the hygiene performance, particularly at retail, has a significant impact on the occurrence of Salmonella. This implies that there is no direct link between slaughterhouse Salmonella surveillance data and the level of Salmonella contamination at retail. To improve risk assessment of Salmonella in fresh pork meat, this study underlines the need for comprehensive retail data.     

Helminth and protozoan parasites in dogs and cats in Belgium

This study investigates the level of helminthic and protozoal infestation over the last 10 years in strays, well-cared-for dogs and cats. Determination of the prevalence of infections was based either on faecal examination or on worm counts at necropsy. Of 2324 faecal flotations (NaCl sp.gr. 1.20) of stray dogs, 34.2% had eggs or proglottids of one or more worm species consisting of Toxocara canis (17.4%), Toxascaris leonina (10.1%), Uncinaria stenocephala (11.4%), Trichuris vulpis (7.0%) and cestodes (2.1%). Isospora oocysts were observed in 5.2% of the dogs. The data on the distribution of the various worm species in the positive dogs indicate that T. canis eggs were by far the most common (50.9%). Necropsy data from 212 infected dogs indicate that 38.9% were infected with T. canis and 33.7% with T. leonina. The overall prevalence of worm infestation of 246 well-cared-for kennel dogs, based on worm egg counts by the McMaster technique, was 36.1%. Of 30 feline faecal samples examined by flotation, 83.3% were positive for parasites, including Toxocara cati (60%), Ancylostoma tubaeformae (36.6%), Taenia (Hydatigera) taeniaeformis (20%) and coccidia (30%). Toxocara cati was the most frequently found worm species at the necropsy of 25 cats (52%). Toxoplasma was not observed.     

Sanguinarine metabolism and pharmacokinetics study in vitro and in vivo

Sanguinarine (SA) is a benzo[c] phenanthridine alkaloid which has a variety of pharmacological properties. However, very little was known about the pharmacokinetics of SA and its metabolite dihydrosanguinarine (DHSA) in pigs. The purpose of this work was to study the intestinal metabolism of SA in vitro and in vivo. Reductive metabolite DHSA was detected during incubation of SA with intestinal mucosa microsomes, cytosol, and gut flora. After oral (p.o.) administration of SA, the result showed SA might be reduced to DHSA in pig intestine. After i.m. administration, SA and DHSA rapidly increased to reach their peak concentrations (C_max, 30.16 ± 5.85, 5.61 ± 0.73 ng/ml, respectively) at 0.25 hr. Both compounds were completely eliminated from the plasma after 24 hr. After single oral administration, SA and DHSA rapidly increased to reach their C_max (3.41 ± 0.36, 2.41 ± 0.24 ng/ml, respectively) at 2.75 ± 0.27 hr. The half-life (T_1/2) values were 2.33 ± 0.11 hr and 2.20 ± 0.12 hr for SA and DHSA, respectively. After multiple oral administration, the average steady-state concentrations (C_ss) of SA and DHSA were 3.03 ± 0.39 and 1.42 ± 0.20 ng/ml. The accumulation indexes for SA and DHSA were 1.21 and 1.11. The work reported here provides important information on the metabolism sites and pharmacokinetic character of SA. It explains the reasons for low toxicity of SA, which is useful for the evaluation of its performance.     

Chlortetracycline in swine-bioavailability and pharmacokinetics in fasted and fed pigs

Chlortetracycline hydrochloride was administered intra-arterially (11 mg/kg) and as an oral drench (33 mg/kg) to ten 21.0-31.5-kg pigs. Five of the pigs were fasted 18 h prior to dosing and five of the pigs were fed ad libitum prior to dosing. The mean volume of distribution determined by area-under-the-curve calculations for the fasted pigs (0.967 +/- 0.210 l/kg) was significantly less (P less than 0.05) than the mean volume of distribution for the fed pigs (1.39 +/- 0.31 l/kg). Mean total body clearance of the drug was also significantly less (P less than 0.05) in the fasted pigs (0.165 +/- 0.055 l/kg/h) as compared to the fed pigs (0.307 +/- 0.053 l/kg/h). The elimination constants (beta) were not found to be statistically different (P less than 0.05): 0.1811 +/- 0.0057 for the fasted pigs; 0.2260 +/- 0.0461 for the fed pigs. The bioavailability for both groups was similar; 19.12 +/- 8.3% for the fasted pigs and 17.88 +/- 5.3% for the fed pigs. In a second experiment three groups of six pigs which weighed 34.5-44.1 kg were fed a corn-soy diet ad libitum. The rations were fortified with chlortetracycline at 100, 400 or 1000 mg chlortetracycline hydrochloride/kg feed. Chlortetracycline concentrations were determined in plasma samples collected over a 6-day period. Plasma chlortetracycline concentrations reach a plateau within 24 h after initial access to the trial diets and were highly correlated with the dose of the drug consumed (r2 = 0.97).     

2005年国内蛋、肉鸡市场分析回顾及2006年走势预测

2005年如果没有年底的禽流感疫情,对于我国蛋鸡、肉鸡生产来说应该是一个非常完美的丰收年,是哪些因素导致了2005年蛋鸡市场如此好的行情?2006年我国家禽市场又将走向何方?……作者对以上热点问题进行了深入分析研究,供读者参考。     

Pharmacokinetics of penicillin-G in ewes and cows in late pregnancy and in early lactation

Concentrations of penicillin-G in serum were determined after single intravenous doses of potassium penicillin-G (10 mg/kg body wt) to ewes and cows in late pregnancy and in early lactation. Penicillin-G in serum was analysed by a microbiological method and pharmacokinetic parameters were calculated by model-independent methods. Serum concentrations were lower in early lactation than in late pregnancy in both ewes and cows. The differences were statistically significant at most sampling times in ewes but only during the first hour in cows.
Weight corrected values of clearance and volume of distribution were significantly higher in early lactation than in late pregnancy in both ewes and cows. Mean residence time and elimination-half life were shorter in lactating than in pregnant ewes, however for the latter parameter the difference was not statistically significant. Neither of these parameters changed in cows.
It is concluded that in both ewes and cows pharmacokinetic parameters of penicillin-G are altered from late pregnancy to early lactation but that these changes have little practical impact and do not call for a revised dosage regime of the studied drug.     

Mycobiota and aflatoxins in raw materials and pet food in Brazil

Commercial feedstuffs are a basic element in modern pet husbandry in the world. In dogs, the effect of mycotoxins is severe and can lead to death. Few reports on the influence of dietary mycotoxins were found in the scientific literature. The aims of this work were to isolate and identify the mycoflora and to determine the aflatoxins (AFs) natural occurrence in raw materials and ready dry pet food. Therefore, the aflatoxigenic capacity of Aspergillus flavus species was investigated. Aspergillus was the prevalent genera (65-89%) followed by Penicillium and Fusarium spp. Aspergillus flavus was the most prevalent species, followed by Aspergillus sydowii, Aspergillus fumigatus and Aspergillus versicolor. Aspergillus flavus frequencies ranged from 58% to 86% except in sorghum meal. All samples assayed (except corn grains and ready pet food) showed Fusarium spp. contamination. Corn meal and corn meal and gluten samples had 100% Fusarium verticillioides. Fusarium graminearum was isolated from sorghum meal. Aspergillus flavus strains (75%) isolated from raw materials and 57% from pet food were able to produce AFs. All samples showed AFs contamination percentages over 70%; corn and sorghum meal obtained the highest AFs levels. Ready pet food did not show quantitative levels of the tested toxins. This is the first report of the aflatoxigenic capacity by A. flavus from Brazilian pet food.