Detection and genetic diversity of porcine rotavirus A,B and C in eastern Australian piggeries

Rotaviruses (RV) have a high prevalence in piggeries worldwide and are one of the major pathogens causing severe diarrhoea in young pigs. RV species A, B, and C have been linked to piglet diarrhoea in Australian pig herds, but their genetic diversity has not been studied in detail. Based on sequencing of the structural viral protein 7 (VP7) RVA G genotypes G3, G4 and G5, and RVC types G1, G3, G5, and G6 have been identified in Australian piggeries in previous studies. Although occurrence of RVB was reported in Australia in 1988, no further genetic analysis has been conducted. To improve health management decisions in Australian pig herds, more information on RV prevalence and genetic diversity is needed. Here, 243 enteric samples collected from 20 pig farms within Eastern Australia were analysed for the presence of RV in different age groups using a novel PCR-based multiplex assay (Pork MultiPath™ enteric panel). RVA, RVB, and RVC were detected in 10, 14, and 14 farms, respectively. Further sequencing of VP7 in selected RV-positive samples revealed G genotypes G2, G5, G9 (RVA), G6, G8, G14, G16, G20 (RVB), and G1, G3, G5, G6 (RVC) present. RVA was only detected in young (<10 weeks old) pigs whereas RVB and RVC were also detected in older animals (>11 weeks old). Interestingly, RVB and RVC G-type occurrence differed between age groups. In conclusion, this study provides new insights on the prevalence and diversity of different RV species in pig herds of Eastern Australia whilst demonstrating the ability of the Pork MultiPath™ technology to accurately differentiate between these RV species.     

新冠肺炎疫情与猪肉价格波动初探

基于2020年3月-2020年10月猪肉价格及新冠肺炎疫情指数,借助VAR模型,定量研究新冠肺炎疫情对于猪肉价格的影响。研究结果表明:新冠肺炎疫情对猪肉价格存在影响,促使猪肉价格上涨,在此基础上文章提出相应措施。     

基于Markov随机场的猪肉糜微结构图像模拟

利用Markov随机场和Gibbs分布理论，建立了猪肉糜微结构图像的随机场模型，然后通过迭代方法，对不同微结构的猪肉糜图像进行了随机模拟，同时对随机模拟图像和原始图像作了对比分析。糜状食品物料微观结构图像的分析和模拟是定研究其微结构模式形态对流变特性影响的关键问题。通过从已知流变特性反演糜状食品物料微结构的几何形态，可以更深入地探讨、研究微结构形成的动力学机制和过程，进而沟通流变特性和微结构形态之间的联系，从而为定量描述糜状食品物料的流变特性提供了条件。     

城市猪肉产品安全供给标识及信息整合技术研究

在探讨中国猪肉供应现状的基础上,提出城市猪肉产品安全供给标识及信息整合技术的应用原理和方法.介绍该技术的使用思路和实施关键,指出了该技术的应用是农业信息化建设中的重要一环.     

添加鸡粪再生饲料猪肉中肌苷酸含量的测定

本文测定了添加不同量鸡粪再生饲料猪肉中肌苷酸的含量。结果表明各组之间差异不显著(P>0.05),适量添加鸡粪再生饲料对猪肉中肌苷酸的含量无影响。     

速冻水饺猪肉馅品质的变化与控制

[目的]研究速冻水饺的肉馅随冻藏时间的延长,其品质变化的情况,以及通过抗氧化剂的添加对延缓其品质下降作用的影响.[方法]通过添加不同抗氧化剂,研究速冻水饺肉馅在冻藏90d过程中肉馅脂肪氧化程度以及对内馅品质的影响.以硫代巴比妥酸值（TBARS）来衡量脂肪氧化程度,通过解冻损失、蒸煮损失以及质构（TPA）的测定,来判断肉馅的品质变化.[结果]试验表明,随着冻藏时间的延长,水饺肉馅的TBARS值不断升高,脂肪氧化不断加深,90d后丙二醛含量超过2 mg/kg,同时肉馅解冻损失、蒸煮损失都有所增加,持水性下降,硬度、弹性、粘聚性、咀嚼性整体上呈下降趋势;添加0.010％的丁基羟基茴香醚（BHA）和0.010％的二丁基羟基甲苯（BHT）,明显降低了TBARS值,分别为0.68和0.75 mg/kg,同时各项品质指标变化程度也变小,且复合添加0.005％ BHA＋0.005％ BHT效果更优,其TBARS值为0.61 mg/kg,其他指标也略优于单独使用.[结论]研究可为提升速冻水饺品质提供一定的参考依据.     

冷却包装猪肉辐照异味气体成分研究

 【目的】研究冷却真空包装辐照猪肉异味气体主要成分和寻找异味源,为探明异味产生机理及去除方法奠定理论基础。【方法】用真空系统液氮冷却装置收集冷却真空包装猪肉辐照异味气体,用气相色谱质谱联用仪测定收集气体成分,确定异味气体成分并推测异味源。【结果】冷却真空包装猪肉辐照异味气体主要成分是二甲硫、二甲二硫、甲硫醇、乙酸甲硫醇酯;辐照异味气体来源于肉中半胱氨酸、蛋氨酸和维生素B1。异味气体量随辐照剂量增加而增加（0～3 kGy）,随辐照后冷藏时间延长而下降,与包装类型密切相关（P＜0.05）。【结论】冷却真空包装猪肉辐照异味气体主要成分为含硫化合物,来源于含硫氨基酸和维生素B1。     

HPLC-MS法测定猪肉中地西泮等5种禁用药物的残留量

[目的]建立快速、准确、高灵敏度的测定猪肉中地西泮等5种禁用药物残留量的分析方法。[方法]采用高效液相色谱-串联质谱联用法(HPLC-MS),通过不同的离子模式进行猪肉中5种禁用药物残留量的测定,其中地西泮、丙酸睾酮、氯丙嗪采用正离子模式,玉米赤霉醇以及己烯雌酚采用负离子模式,并进行多反应检测(MRM)。[结果]试验显示,该方法的线性范围为:3~100 ng/m L,标准曲线线性良好,其回归方程及相关系数分别为地西泮:Y=27 200X-0.009 31,R=1.000 0;丙酸睾酮:Y=13 800X-0.000 147,R=1.000 0;氯丙嗪:Y=0.095 1X+0.025 7,R=0.999 9;玉米赤霉醇:Y=44 100X-0.006 58,R=1.000 0;己烯雌酚:Y=0.093 4X+0.018 8,R=0.998 9。回收率分别为:地西泮100.50%~111.30%;丙酸睾酮73.30%~84.20%;氯丙嗪70.30%~99.10%;玉米赤霉醇69.90%~75.30%;己烯雌酚84.70%~117.70%。最低检出限分别为:地西泮0.4μg/kg,丙酸睾酮0.6μg/kg,氯丙嗪0.3μg/kg,玉米赤霉醇0.5μg/kg,己烯雌酚0.8μg/kg。[结论]该方法操作简便、快速,是动物源性食品中地西泮等5种禁用药物残留的快速而准确的检测方法。     

Responses in carcass lean pH at 24 hours post-mortem in lines of Large White pigs selected for growth rate on a fixed ration over a set time

A restricted maximum likelihood analysis applied to an animal model showed no significant differences (P > 0.05) in pH value of the longissimus dorsi measured at 24 h post-mortem (pH24) between high and low lines of Large White pigs selected over 4 years for post-weaning growth rate on restricted feeding. Genetic and phenotypic correlations between pH24 and production and carcass traits were estimated using all performance testing records combined with the pH24 measurements (5.05–7.02) on slaughtered animals. The estimate of heritability for pH24 was moderate (0.29 ± 0.18). Genetic correlations between pH24 and production or carcass composition traits, except for ultrasonic backfat (UBF), were not significantly different from zero. UBF had a moderate, positive genetic correlation with pH24 (0.24 ± 0.33). These estimates of genetic correlations affirmed that selection for increased growth rate on restricted feeding is likely to result in limited changes in pH24 and pork quality since the selection does not put a high emphasis on reduced fatness.     

Assessing hygiene proficiency on organic and conventional pig farms regarding pork safety: A pilot study in Finland

A key element in the EU Common Agricultural Policy (CAP) will be a single farm payment system that is linked to compliance with rules on, for instance hygiene standards. However, there are no recommended methods for assessing the hygiene proficiency of pig production farms. The present study was undertaken to develop a method for this purpose. A first implementation was done on pilot scale; with a set of both conventional and organic pig farms (N = 15). Fifty hygiene-related factors were selected, especially with reference to the possible proliferation of enteric pathogens Listeria monocytogenes, Yersinia enterocolitica and Yersinia pseudotuberculosis. The factors were allocated into 8 evaluation categories: (1) general production management, (2) animal density, (3) the outdoor area for pigs, (4) pest and pet animals, (5) general hygiene in the piggery, (6) pen hygiene, (7) feed production hygiene, and (8) feeding hygiene. A farm questionnaire and a supplementary on-site observation form were devised, and one arbitrary scale of hygiene points assigned for each factor. In addition to the mailed questionnaires, one person subsequently visited all the farms, perused the questionnaire with the owners and completed the observation form. The hygiene scores of the farms in each evaluation category were compared both without weighting and with weighting based on expert opinions. The method proved to be feasible and applicable to different types of production.