牛卵母细胞体外成熟技术研究

从两方面探讨了牛卵母细胞的体外成熟培养效果,即对不同级别和不同卵巢卵泡直径的卵丘卵母细胞复合体（COCs）进行成熟培养,测定其成熟率。COCs级别不同,培养成熟率之间存在很大差异,A级COCs成熟率为63．81％,B级为47．81％,显著高于C级和D级（P〈0．01）。卵母细胞的成熟率与采集COCs时的卵泡直径关系密切。中等卵泡的卵母细胞的成熟率为61．82％,显著高于小卵泡和大卵泡（P〈0．01）。试验结果表明：A级和B级COCs是卵母细胞体外培养的主要资源;在卵母细胞体外培养过程中,宜选择卵泡发育水平基本正常的中等卵泡采集COCs,而不宜选择发育过大或过小的卵泡。     

Population pharmacokinetics of enrofloxacin and its active metabolite ciprofloxacin in ill cows

This study was performed in 105 ill cows to determine the best practical individualized dose of enrofloxacin after i.m. (2.5 mg/kg) single-dose administration. Samples were collected from each cow at random time to ensure the percentage of samples distributed equally in the absorption phase, distribution phase, and elimination phase of the drug. Drug concentrations were determined by high-performance liquid chromatography with fluorometric detector, analyzed by population pharmacokinetic (PPK) modeling with NONMEM. The concentration–time data for enrofloxacin in plasma and ciprofloxacin were fitted to the one-compartment model with first-order absorption and elimination. The final covariate model indicated that body weight and daily milk productions have significant influence on clearance (CL) of enrofloxacin and ciprofloxacin, and the volume ( V ) of distribution of enrofloxacin. The typical PPK parameters were K _a = 3.33 h⁻¹, CL = 1.25 L/h/kg, and V  = 2.98 L/kg of enrofloxacin, and the interindividual variability for CL and V were 20.2% and 24.3%, respectively, the population mean estimates of K _a, CL, and V for ciprofloxacin were 1.12 h⁻¹, 2.36 L/h/kg, 8.20 L/kg, respectively, and their interindividual variability was 36.9%, 15.8% and 14.1%, respectively.     

湖南省一起非洲猪瘟疫情的暴发调查

2018年11月21日,农业农村部通报湖南省怀化市鹤城区排查出非洲猪瘟疫情。为追溯这起非洲猪瘟疫情的来源,怀化市动物疫病预防控制中心开展了流行病学调查,从生猪调运、饲料、泔水、生物安全等风险因素入手,结合流行病学关联养殖场血清以及饲料、泔水、关联屠宰场环境及冻库冷冻猪肉产品等样品的实验室检测,综合分析非洲猪瘟传播的可能途径。调查结果显示:疫情猪场2018年10月曾使用收购的泔水喂养生猪;泔水、冷冻猪肉产品非洲猪瘟病毒(ASFV)核酸阳性检出率分别为0.9%(3/348)、25.6%(10/39),而血清和饲料样品全为阴性;在冻库、餐饮机构和销售终端检出ASFV核酸阳性样品,阳性检出率分别为16.7%、1.8%、7.7%。调查分析显示,该疫情猪场的泔水饲喂时间、发病时间与ASFV自然感染的潜伏期相符,且与泔水有关联的某物流公司冻库猪肉被产品检测出ASFV核酸阳性。综上表明,泔水喂养引起该非洲猪瘟疫情的可能性最大。依据调查结果,采取严格生猪及其产品移动监管,强化落实禁止泔水饲喂政策,加强生物安全管理等一系列防控措施,使疫情得到了有效控制。     

新训犬员"四做到"

新训犬员由于初次带犬,还不能很好的掌握犬的行为特点和生活习性,个别人甚至对犬存在畏惧心理,在操作技能上也是一片空白,有时会觉得无从下手。如何提高新训犬员的基本技能,笔者认为应做到以下四个方面：     

The production of short chain fatty acid and colonic development in weaning piglets

Weaning process widely affects the small intestinal structure and function in piglets, while the responses of large intestine to weaning stress are still obscure. The purpose of this study was to determine the developmental changes (i.e., short chain fatty acids (SCFAs) concentrations, growth parameters, crypt‐related indices and antioxidant capacity) in colon of piglet during weaning. Forty piglets were weaned at day 21 and euthanized to collect colonic tissues and digesta samples on day 0, 1, 3, 7 and 14 post‐weaning (n = 8). Piglet growth performance was improved (p < .001) on day 7 and 14 post‐weaning. The concentrations of acetate, propionate, butyrate, valerate, isobutyrate, isovalerate and total SCFAs were higher (p < .001) during the late post‐weaning period. The mRNA abundances of SCFAs transporters were greater (p < .001) on day 7 and 14. The absolute and relative weights, absolute length and perimeter of colon were greater (p < .001) on day 7 and 14. Similarly, post‐weaning increases (p < .001) in colonic crypt depth and Ki67 positive cells numbers per crypt were observed during the same period. Colonic crypt fission indices decreased (p < .01), while total crypt numbers increased (p < .001) on day 14 after weaning. Moreover, total SCFAs concentration was significantly associated with colonic growth parameters and Ki67 cells/crypt (p < .001). In addition, catalase content was decreased on day 3, 7, and 14, whereas, the concentrations of total superoxide dismutase (T‐SOD) and manganese‐containing superoxide dismutase (MnSOD) were higher (p < .05) on day 1 and 3 post‐weaning. These results showed that weaning process has a significant effect on colonic growth and development, which might be associated with the change of SCFAs concentrations in colon.     

Effect of chicken egg yolk immunoglobulins on serum biochemical profiles and intestinal bacterial populations in early‐weaned piglets

This study was conducted to test the hypothesis that dietary supplementation with anti‐E. coli, chicken egg yolk immunoglobulins (IgY), may affect early weaned piglet (EWP) intestinal functions and enteric micro‐organisms. One hundred and forty‐eight ([Landrace × Yorkshire] × Duroc) piglets, weaned at age day 21, were randomly assigned to receive one of three diets for 14 days. Treatment group one (control group) was fed the base diet. Treatment group two (antibiotics group) was fed the base diet which was supplemented with 100 ppm colistin sulphate and 15 ppm enramycin; treatment group three (IgY group) was fed the base diet which was supplemented with 500 mg/kg anti‐E. coli IgY. The study evaluated the effects on EWPs of IgY on growth, serum biochemical, inflammatory profiles and also digestion content intestinal bacterial populations. Results showed no significant difference in diarrhoea rates between IgY‐fed EWPs and antibiotic‐treated EWPs. Serum biochemical analysis showed that EWPs fed an IgY‐containing diet had both lower (p < 0.05) cholesterol and low‐density lipoprotein compared to antibiotic‐treated EWPs. Escherichia coli populations measured in IgY‐fed EWP ileal contents, compared to the control group, were significantly reduced (p < 0.05). Enterococcus, Lactobacillus, Clostridium and Bifidobacterium populations were unaffected by the IgY treatment. Larger (p < 0.05) Enterococcus populations and lower (p < 0.05) expression levels of heat‐stable enterotoxin b (STb) were observed in IgY‐fed EWP caecal digesta compared to the control group. Enteric Lactobacillus significantly decreased (p < 0.05) in EWPs fed antibiotics while it was unaffected by IgY treatment. Dietary supplementation with anti‐E. coli IgY has the potential to suppress enteric E. coli growth, but not Lactobacillus, Clostridium and Bifidobacterium. This promotes and maintains a healthy EWP intestinal environment. These findings suggest that IgY may be used as an alternative to antibiotics in EWP diets.     

Combined microRNAome and transcriptome analysis of follicular phase and luteal phase in porcine ovaries

The aim of this study was to explore the expression difference of miRNAs and mRNAs between the follicular phase (FP) and luteal phase (LP) in porcine ovaries and provide a theoretical basis for the research on mammalian reproductive regulation. RNA‐Seq and miRNA‐Seq were used to identify differentially expressed genes (DEGs) and miRNAs (DEMs) between the FP and LP in ovaries of six sows (3‐year‐old Yorkshire pigs with similar weights and same parities). Bioinformatic analysis was used to screen potential genes and miRNAs related to porcine ovarian function. Real‐time qualitative PCR was used to validate the sequencing results. RNA‐Seq results showed that 3,078 genes were up‐regulated, and 1,444 genes were down‐regulated in the LP compared with the FP, and DEGs were significantly enriched in 242 Gene Ontology (GO) terms and 33 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. miRNA‐Seq identified 112 DEMs, of which 25 were up‐regulated and 87 were down‐regulated in the LP compared with the FP. We obtained 186 intersection genes (IGs) between the 4,522 DEGs and 2,444 target genes predicted from the 112 DEMs. After constructing a miRNA‐gene‐pathway network, we identified key miRNAs and genes including miR‐17‐3p, miR‐214, miR‐221‐5p, miR‐125b, FGF1, YWHAG, YWHAZ, FDFT1 and DHCR24, which are enriched in Hippo and PI3K‐Akt signalling pathways, and various metabolic pathways. These results indicate that these key genes and miRNAs may play important roles in the developmental transition from FP to LP in porcine ovaries and represent candidate targets for further study.     

铜对意大利蜜蜂工蜂生理机能的影响

本研究旨在探索意大利蜜蜂工蜂成蜂饲粮中铜的添加水平对蜜蜂生长发育、生理生化及抗氧化性能的影响。从蜂群中随机取3000只刚出房的蜜蜂,随机平均分成6组,分别命名为A、B、C、D、E、F,每组5个重复,每个重复100只蜜蜂;6组工蜂幼虫分别饲喂铜的添加水平为0.00、2.00、4.00、6.00、8.00、10.00μg/g的糖水,饲养至全部死亡。分别取成蜂测定体成分、血淋巴生化指标、抗氧化指标、相关基因表达量、制作中肠切片,并测定寿命。结果表明:(1)铜对蜜蜂寿命的影响显著,从蜜蜂存活率曲线图来看,当饲粮中铜的添加水平为2.00μg/g时对蜜蜂中肠食膜的结构最为有利。(2)与对照组相比,铜的添加水平为2.00~10.00μg/g组9日龄蜜蜂体组织铜含量显著升高(P<0.05),蜜蜂血淋巴中总蛋白(TP)和总胆固醇(TCHO)含量显著降低(P<0.05)。(3)9日龄蜜蜂蜂体超氧化物歧化酶(Cu/Zn-SOD)活性随着铜添加水平的提高出现先升高后降低的趋势,在2.00μg/g时活性最高(P<0.05)。(4)当饲粮中铜的添加水平在0.00~10.00μg/g的范围内不断升高时,CAT、Ctr1基因相对表达量显著增加(P<0.05)。由此得出饲粮中铜的添加水平对蜜蜂的生理机能影响显著。     

响应面法优化鸡α干扰素工程菌发酵培养基

本研究采用单因素试验和响应面法相结合的方式优化毕赤酵母重组菌的发酵培养基,以提高毕赤酵母发酵液的生物量。首先,通过单因素试验确定最优碳、氮源分别为甘油和NH4H2PO4;然后,采用Plackett-Burman试验、最陡爬坡试验及Box-Behnken响应面分析并结合Design Expert统计分析软件构建响应方程。利用该方程预测得到最佳培养基配方:甘油46g/L,NH4H2PO414g/L,K2SO418g/L,MgSO415g/L,CaSO41.0g/L,KH2PO45g/L,KOH1.5g/L,初始pH6.96,PTM1盐4.4mL/L。此条件下毕赤酵母发酵后湿重具有最高值为175.54g/L,生物量比优化前提高了50%,并且培养基成本低廉,成分简单,方便调控,适合大规模发酵生产。     

青稞替代玉米对育肥牦牛生产性能和肉品质的影响

本试验旨在研究青稞替代玉米对育肥牦牛生产性能、屠宰性能、养分表观消化率及肉品质的影响。采用2×3交叉设计,以日粮类型(玉米、60%青稞+40%玉米)和不同精粗比(30∶70、40∶60和50∶50)为两因素,选取36头年龄4周岁左右、体重为(144±21.0)kg的麦洼公牦牛,随机分为6组,每组6个重复,每个重复1头牛。预饲期15d,正试期180d。结果表明:1)日粮类型及精粗比对牦牛生产性能无显著影响(P>0.05)。2)青稞-玉米组的净肉率显著高于玉米组(P<0.05),但屠宰率和眼肌面积无显著差异(P>0.05);精粗比对屠宰性能无显著影响(P>0.05);日粮类型和精粗比二因素对眼肌面积的互作影响显著(P<0.05),以青稞-玉米(40∶60)组效果最优。3)日粮类型对养分表观消化率无显著影响(P>0.05);与30∶70相比,40∶60和50∶50极显著提高了有机物(OM)和总能(GE)的表观消化率(P<0.01)、显著提高了粗蛋白(CP)的表观消化率(P<0.05);日粮类型和精粗比二因素对GE、OM和粗脂肪(EE)的表观消化率有显著的互作影响(P<0.05),以玉米(40∶60)组效果最佳。4)青稞-玉米组和玉米组背最长肌亮度值(L*)、红度值(a*)、pH值均无显著差异(P>0.05),但青稞-玉米组的黄度值(b*)和滴水损失显著低于玉米组(P<0.05)、蒸煮损失极显著低于玉米组(P<0.01);随着精粗比的升高,蒸煮损失有逐渐降低的趋势(P=0.075)。5)日粮类型对背最长肌的嫩度无显著影响(P>0.05);随着精粗比的升高,剪切力逐渐减小(P>0.05),肌纤维直径有减小的趋势(P=0.059),肌纤维密度显著增加(P<0.05),肌纤维面积显著减小(P<0.05)。综上所述,以青稞替代日粮中60%的玉米能够提高育肥牦牛的屠宰性能,改善牦牛肉的品质;日粮精粗比为40∶60时饲喂效果最佳。