半滑舌鳎源美人鱼发光杆菌美人鱼亚种的分离鉴定

2016年5月河北省秦皇岛市昌黎县某海水养殖基地半滑舌鳎突发大批死亡,为了确定引起死亡的病原菌,无菌采集心血进行病原菌分离鉴定,16S rDNA基因序列分析与GenBank中公布的美人鱼发光杆菌参考株序列同源性为99.6%,被鉴定为美人鱼发光杆菌;进一步通过生化特性分析,被确认为美人鱼发光杆菌美人鱼亚种。动物回归试验结果表明,其对舌鳎鱼具有很强的致病性,其LD_(50)为3.1×10~4CFU/mL,且对哺乳动物具有致病性。药敏试验结果显示,分离菌对诺氟沙星、恩诺沙星、环丙沙星,乙酰甲喹高度敏感;对多西环素、阿米卡星中敏感;对庆大霉素、头孢曲松、替米考星等不敏感。     

UHPLC-Q/TOF MS结合HPLC-DAD定性和定量分析硫酸黏菌素可溶性粉中的未知添加物

定性和定量分析一批兽药硫酸黏菌素可溶性粉中的未知添加物。照《中国兽药典》2010年版一部对该批检品用微生物检定法进行含量测定时,发现该样品的抑菌圈为虚圈,用薄层色谱鉴别该样品,未显示与标准品溶液一致的主斑点,怀疑该样品中有处方外非法添加物。采用超高效液相色谱-四级杆-飞行时间质谱(UHPLC-Q/TOF MS)对该样品进行筛查,发现疑似添加物,并使用液相色谱-二极管阵列检测(HPLC-DAD)法进行了双重确证和含量测定。该样品中非法添加物确证为磺胺氯达嗪和甲氧苄啶,添加量分别为58.5 mg/g和13.4 mg/g。本研究通过建立筛查方法为监管部门提供技术支撑,通过分析非法添加物的可能原因为打击兽药处方外非法添加提供了思路。     

开食料中不同NDF水平对犊牛生长性能、瘤胃内环境及血清生化指标的影响

为探索开食料中不同NDF水平对犊牛生长、瘤胃发酵参数以及血清生化指标的影响,选用初生重相近(42±2.5) kg、饲喂足量初乳的中国荷斯坦犊牛60头,其中公犊牛36头,母犊牛24头。随机分为A、B、C和D 4个处理组,每个处理15头,其中9头公犊牛+6头母犊牛,试验犊牛于犊牛岛(1.5 m×3.4 m)单独饲养。15日龄开始分别饲喂NDF水平不同的4种开食料,分别为:A处理10%,B处理15%,C处理20%和D处理25%,70日龄断奶,试验期112 d。结果表明:1)0~42日龄和70~112日龄,B组日增重均高于A、C和D组(P<0.05),分别高出45.69、39.79、117.13 g·d^-1和35.33、153.29、 145.93 g·d^-1。70~112日龄,B、C和D组开食料采食量显著高于A组(P<0.05),分别高出255.20、252.48和392.27 g·d^-1。A(0.61)和B(0.60)组犊牛的饲料转化率显著高于C(0.55)和D(0.54)组(P<0.05);2)犊牛瘤胃pH在35和70日龄时,C组显著高于其他3组(P<0.05),112日龄时,A和B组显著高于C和D组(P<0.05);3)瘤胃NH₃-N含量在90日龄前差异不显著(P>0.05),但在112日龄时, B、C和D组较A组显著降低16.72%、44.19%和52.10%(P<0.05);4)C和D组乙酸比例显著高于A和B组(P<0.05);B组丙酸比例较A、C和D组高出4.24%、3.18%和6.43% (P<0.05),乙酸/丙酸显著低于A、C和D组(P<0.05);5)各处理组间血清总蛋白、葡萄糖和尿素氮含量无显著差异(P>0.05)。1~3月龄犊牛开食料中NDF适宜水平为15%有利于提高断奶后日增重,促进饲料利用效率,改善瘤胃内环境,且对犊牛血清生化指标无不利影响。     

日粮中添加牛至油对河西绒山羊育肥性能的影响研究

牛至精油对家畜生产性能和免疫力的提高有重要的影响。通过在日粮中添加牛至精油育肥河西绒山羊,研究其对河西绒山羊生长性能、屠宰性能及胴体品质的影响。对照组饲喂基础日粮,试验组在饲喂的基础日粮中分别添加4和7 g宜生饲宝(含牛至精油的添加剂),4和7 g宜生饲宝中牛至精油的含量分别为52和91 mg。对照组和试验组均为同月龄、同体重的河西绒山羊羯羊,试验组和对照组均设3个重复,每个重复5只羊。育肥期为90 d,每30 d为1个阶段。试验结果表明:育肥全期,对照组、4 g组和7 g组河西绒山羊平均日增重分别为96.30、172.22和169.82 g·d^-1,4 g组和7 g组分别显著高于对照组(P<0.05),4 g组和7 g组无显著差异(P>0.05);屠宰性状,胴体重对照组、4 g组和7 g组分别为20.24、24.18和23.90 kg,无显著差异(P>0.05),屠宰率对照组、4 g组和7 g组分别为48.86%、51.21%和51.56%,4 g组和7 g组分别显著高于对照组(P<0.05),4 g组和7 g组无显著差异(P>0.05),胴体净肉重对照组、4 g组和7 g组分别为12.90、16.27和15.99 kg,4 g组和7 g组分别显著高于对照组(P<0.05),4 g组和7 g组无显著差异(P>0.05);肉质性状,大理石纹4 g组和7 g组分别显著高于对照组(P<0.05),4 g组和7 g组无显著差异(P>0.05),pH、熟肉率、失水率、嫩度、蒸煮损失对照组、4 g组、7 g组间均无显著差异(P>0.05)。日粮中添加牛至油可以显著提高河西绒山羊的育肥性能,本试验日粮中添加4 g宜生饲宝(含牛至精油52 mg)效果最佳。     

中国荷斯坦牛部分乳房结构特性对泌乳性能的影响

本研究对规模化场奶牛乳房结构部分性状进行评价和测定,旨在分析其影响因素及其与泌乳性能的关系。现场评价和测定我国北方6个规模化奶牛场荷斯坦牛的乳房均衡(2 030条)、乳头长度(1 551条)和乳头位置评分(分前、后乳头,2 839条),使用SAS 9.2 GLM过程采用固定效应模型分析影响上述3个乳房性状的因素,同时分析3个单项性状对校正日产奶量和体细胞评分的影响。结果表明:场和胎次对3个乳房性状影响极显著(P0.01);前、后乳头位置和后乳头长度对校正日产奶量有显著影响(P0.05),校正日产奶量与前乳头位置评分值呈正比,与后乳头位置评分值呈反比;前乳头位置和长度对体细胞评分有显著影响(P0.05),体细胞评分随前乳头位置评分的增大而减小;5~5.5 cm的乳头长度对于校正日产奶量和体细胞评分都最佳。本研究结果为通过乳房性状选择、淘汰并提高奶牛的生产性能、乳房健康提供了参考。     

Effect on Rendement Napole genotype on metabolic markers in Ossabaw pigs fed different levels of fat

We investigated effects of Rendement Napole (RN ) genotype on metabolic markers in Ossabaw pigs fed diets with different levels of dietary fat. Thirty‐two pigs, belonging to either the wild‐type (WT , rn⁺/rn⁺) or carrier (CAR , RN ^?/rn⁺) genotypes (n  = 16/genotype), were divided into two dietary groups, (high fat [HF ] or low fat [LF ]) diets, for 12 weeks (n  = 8 pigs/genotype/diet) after which pigs were killed for gene expression analysis by RT ‐PCR . Feeding HF diet caused increased daily gain (ADG , p  <  .05) and final body weight (BW ) (p  <  .05) in comparison with the LF diet (p  <  .05). Feed efficiency (gain:feed) was higher (p  <  .05) in pigs on the HF and was higher (p  <  .05) in CAR pigs compared to WT . There was genotype × diet interaction (p  =  .05) on final BW such that CAR animals on LF diet had the same final BW as animals of both genotypes on HF diet. Carrier pigs on LF diet had higher (p  <  .05) average daily gain and gain:feed than WT pigs. There was a trend (p  <  .08) for a higher feed consumption in pigs on the LF diet. Backfat thickness was higher (p  <  .01) in pigs on the HF diet. Serum triglyceride was higher (0.62 vs. 0.33 mg/dl, p  <  .01) in pigs on HF diet. Serum insulin was higher (p  <  .05) in CAR versus WT pigs (0.40 vs. 0.015 μg/ml). Pigs on the HF diet had a higher (p  <  .05) serum insulin compared to those on the LF diet (0.032 vs. 0.023 μg/ml). Carnitine palmitoyl transferase 1‐alpha was higher (p  <  .05) in the longissimus dorsi and semitendinosus muscles of pigs on HF diet. Acyl‐CoA oxidase I was elevated (p  <  .05) in the liver of pigs on HF diet. Fatty acid synthase was lower in the longissimus dorsi muscle, liver and mesenteric fat (p  <  .05) of carrier pigs. The RN gene regulates specific metabolic markers in the Ossabaw pigs.     

Effects of in ovo feeding of L‐arginine on the development of digestive organs,intestinal function and post‐hatch performance of broiler embryos and hatchlings

This study was to investigate the effects of in ovo feeding (IOF) L‐arginine (Arg) solution on the development of digestive organs, the duodenal mucosa of broiler embryos and hatchlings, and the growth performance of chicks during the first week post‐hatch. A total of 720 fertilized eggs with similar weight were randomly allocated to three groups, consisting of eight replicates of 30 eggs each. Three treatments were arranged as non‐injected control, diluent‐injected (0.75% NaCl solution) group and Arg solution‐injected group containing 1% Arg, dissolved in diluent. At 17.5 days of incubation, 0.6 ml of IOF solution was injected into amniotic fluid of each egg of injected groups. Results showed IOF of Arg solution increased (p < .05) the chick embryo weight at 19 days of incubation; the body weight gain of post‐hatch broilers during 1–7 days; the weights of liver, pancreas, proventriculus and gizzard; the concentrations of duodenal ghrelin, vasoactive intestinal peptide and glucagon‐like peptide 2; and the duodenum mucosal enzyme activities of alkaline phosphatase, maltase, sucrase and inducible nitric oxide synthase of 7‐day‐old post‐hatch broilers compared with other groups. The IOF of Arg solution also increased (p < .05) the villus height (VH) and the ratio of VH to crypt depth (CD) and decreased (p < .05) the CD in duodenum of broiler embryos and post‐hatch hatchlings, except for the CD at 19 days of incubation. In conclusion, IOF of 1% Arg solution into the amnion at 17.5 days of incubation could improve the development of digestive organs, the duodenal morphology, the releasing of gastrointestinal hormones and mucosal enzyme activities of broiler embryos and hatchlings and finally the growth performance of chicks during the first week post‐hatch. Therefore, IOF of appropriate Arg solution could be an effective technology for regulating early nutrition supply and subsequent growth development in poultry industry.     

Effects of milk thistle meal on performance,ileal bacterial enumeration,jejunal morphology and blood lipid peroxidation in laying hens fed diets with different levels of metabolizable energy

This study was conducted to evaluate the effects of different levels of milk thistle meal on performance, blood biochemical indices, ileal bacterial counts and intestinal histology in laying hens fed diets containing different levels of metabolizable energy. A total number of 200 Leghorn laying hens (Hy‐Line W‐36) were randomly assigned to eight experimental treatments with five cage replicates of five birds each. Dietary treatments consisted of four levels of milk thistle meal (0%, 15%, 30% and 60%) and two levels of AME_n (11.09 and 12.34 MJ/kg) fed over a period of 80 days. In vitro studies revealed that the total phenolic component of milk thistle meal was 470.64 mg gallic acid equivalent/g of the sample, and its antioxidant activity for inhibiting the 2‐2‐diphenyl‐1‐picrichydrazyl free radical and reducing ferric ions was about 21% higher than that of butylated hydroxyltoluene (p < .05). Diets containing high level of AME_n led to improved egg production (p < .05), egg weight (p < .05), egg mass (p < .01) and feed conversion ratio (p < .01). In addition, offering diets containing high energy significantly enhanced (p < .01) serum triglyceride and malondialdehyde (MDA) concentrations as well as jejunal villus height. Dietary supplementation of 3% milk thistle meal resulted in the best feed conversion ratio (p < .05), reduction of ileal Escherichia coli enumeration (p < .01) and an enhancement in the villus height‐to‐crypt depth ratio (p < .05). Furthermore, feeding incremental levels of this meal led to remarkable decrease in serum cholesterol, triglyceride and MDA (p < .01) concentrations while significant increase in blood high‐density lipoprotein content and goblet cell numbers (p < .05). The present findings indicate that milk thistle meal with high antioxidant and antibacterial properties in laying hen diets may improve health indices and productive performance.