A novel 31-bp indel in the paired box 7 (PAX7) gene is associated with chicken performance traits

1. A novel 31-bp indel polymorphism in intron 3 of the chicken paired box 7 (PAX7) gene was identified and genotyped in an F₂ resource population of Gushi chicken crossed with Anka broiler to analyse its associations with chicken growth, carcass and meat quality traits.

2. Results showed that the 31-bp indel was significantly associated with body weight at 4, 6, 8, 10, 12 weeks of age and body size indices including shank length, shank girth, body slanting length at 8 and 12 weeks of age. Significant associations were found for carcass weight, semi-evisceration weight, evisceration weight, breast muscle fibre diameter, leg muscle fibre diameter, breast muscle fibre density, while no significant association with leg muscle fibre density was observed.

3. It was concluded that the 31-bp indel in intron 3 of the PAX7 gene was associated with chicken growth, carcass and meat quality traits where the 31-bp deletion had a negative effect on chicken growth and carcass traits and positive effect on meat quality traits.     

对分割肉检疫监管的探讨

公众对肉类产品的需求逐渐由白条肉向品牌化、精细化的分割肉方向发展,相关产品的检验、检疫、监管已成为社会关注的热点。本文对三种不同类型肉品分割行为进行了分析,探讨检疫监管存在的问题,并提出明确监管主体、修订相关法律法规、建立追溯平台、强化主体责任的建议,供同仁参考。     

湖北省武汉市某门诊犬细小病毒病病例统计分析

[目的]了解武汉市犬细小病毒病(CPD)的流行情况和特点。[方法]以华中农业大学动物医院门诊为依托,应用胶体金试纸条和PCR检测技术,对2015年9月至2016年9月的犬门诊病例进行调查分析。[结果]共检测门诊犬病例2 728例,检出CPD阳性121例,阳性检出率为4.4%。从时间分布看,该期间大部分月份的阳性检出率在3%~5%之间,2015年10月的最高,2016年6—9月的最低。从群间分布看,阿拉斯加、边牧、哈士奇、比熊、萨摩耶、博美、巴哥等犬种的CPD阳性数量均占该品种就诊犬总数量的10%以上,而拉布拉多、雪纳瑞、德牧、贵宾、金毛犬则在5%以上;雄性犬的CPD阳性检出率明显高于雌性;在阳性病例中,2~4月龄幼犬的占比最高,在40%~60%之间;未免疫或未按规定免疫犬的CPD阳性数量与总阳性数量的占比高达86.7%,而按规定免疫犬仅为13.3%。[结论]CPD的发生与犬的品种、年龄、性别、免疫状况和气候等因素存在一定的关系,尤其是其年龄和免疫状况。本研究有助于了解该病的流行特点,并可为该病的防治提供参考。     

Influence of stewing time on the texture,ultrastructure and in vitro digestibility of meat from the yellow‐feathered chicken breed

This study assessed the influence of stewing (1, 2 or 3 h) on the texture, ultrastructure and in vitro digestibility of meat from the yellow‐feathered chicken, which is a popular broiler chicken in Asia. Results indicated that longer stewing considerably increased cooking loss of the chicken carcass and tenderness of thigh meat. After 3 h of stewing, protein digestibility decreased from 90.5% to 80.3% and fiber diameter decreased by 8.63 μm. The shear force value of breast meat decreased from 32.34 N at 1 h to 10.29 N at 2 h, and then increased to 39.98 N at 3 h. The texture profile of breast meat remarkably decreased during stewing. Moreover, increased stewing time induced longitudinal and transversal shrinkage of muscle fibers and the degradation of the myosin heavy chain. These findings suggested that prolonged stewing (3 h) resulted in decreased meat qualities, based on the changes in cooking loss, digestibility and texture profile, but that stewing for 2 h increased thigh and breast tenderness. Producers could utilize this information to stew yellow‐feathered chicken meat with desirable qualities.     

Effect of chopping time and heating on 1H nuclear magnetic resonance and rheological behavior of meat batter matrix

The effect of chopping time and heating on physicochemical properties of meat batters was investigated by low‐field nuclear magnetic resonance and rheology technology. Cooking loss and L* increased while texture profile analysis index decreased between chopping 5 and 6 min. The relaxation time T₂₁ (bound water) and its peak area ratio decreased, while the ratio of T₂₂ peak area (immobilized water) in raw meat batters gradually increased with the extension of chopping time. However, T₂₂ was opposite after being heated and a new component T₂₃ (free water) appeared (T_2i is the spin – spin relaxation time for the ith component.). The initial damping factor (Tan δ) gradually decreased and there were significant difference between 4 and 5 min of chopping time. There were significantly positive correlations between the ratio of peak area of T₂₂ and chopping time, the storage modulus (G′), cooking loss, and L*, respectively. Continued chopping time could improve the peak area proportion of T₂₂ in raw meat batters. Further, the higher the peak area proportion of T₂₂ in raw meat batters, the cooking loss of heated meat gel was higher. Also, the stronger the mobility of immobilized water in meat batter, the higher the L* of the fresh meat batters. Thus, it is revealed that the physicochemical properties of meat batter are significantly influenced by chopping time which further affects the water holding capacity and the texture of emulsification gel.     

Effect of grape pomace on fermentation quality and aerobic stability of sweet sorghum silage

The objective of this study was to evaluate the effect of grape pomace (GP) with different adding levels (0%, 5%, 10% and 15%, fresh matter basis), alone (GP‐LAB) or in combine with an inoculant LAB (GP+LAB), on the fermentation quality and aerobic stability of sweet sorghum silage. After 90 days of ensiling in vacuumized mini‐silos, silages were subject to a 7‐day aerobic stability test, in which chemical, microbial and polyphenol composition were measured. In the GP‐LAB group, adding GP decreased (P < 0.05) concentrations of water‐soluble carbohydrate (WSC) and butyric acid in silage. In the GP+LAB group, adding GP increased (P < 0.05) concentrations of lactic acid, WSC and crude protein, decreased (P < 0.05) final pH value, NH₃‐N ratio and butyric acid concentration in silage. Polyphenol level was reduced (P < 0.05) after silage fermentation. During aerobic exposure, the fungi count, pH value and silage temperature increased (P < 0.05), the levels of lactic acid, acetic acid and polyphenols (quercetin 3‐O‐glucoside and quercetin 3‐O‐glucuronid) decreased (P < 0.05) in silage. GP+LAB treated silage had a lag phase for aerobic spoilage. When the fermentation products, microbial counts, chemical and polyphenol composition were considered, the use of 10% GP+LAB at ensiling could provide a valuable source for improved fermentation quality and aerobic stability of sweet sorghum silage.     

Effects of exogenous enzymes and dietary energy on performance and digestive physiology of broilers

The study was conducted to compare the effects of XG with AG and BM at different metabolizable energy diets on growth performance, digestive physiology and energy utilization of broilers fed with corn-SBM diet. A 2 × 4 factorial design was used with two basal diets (the positive control group, PC; negative control with ME reduction 100 kcal/kg, NC) and with or without the addition of three exogenous enzymes (0.02% BM; 0.01% AG; 0.05% XG) respectively. 1,200 one-day-old broilers were randomly allocated to 8 treatments with 10 pens of 15 broilers. There was no significant difference on BW, BWG, and FI at 0-21d, 21-42d or 0-42d for diet, enzymes or their interactions, but FI at 22-42d and 0-42d were tend to be decreased with the addition of enzymes. The F/G was significantly improved by the addition of enzymes especially in NC diet. The dietary AME and TME in PC or NC diet were significantly increased by XG or AG in NC diet. The villus length and V/C of ileum were significantly increased by the addition of BM or XG. XG improved the activities of trypsin, chymotrypsin and amylase, BM improved the activity of trypsin at 21d, and AG improved the activity of chymotrypsin at 21d. Comparing to PC diet, the addition of enzymes in PC or NC diet decreased feed cost per kg body weight gain especially in NC diet (except AG in PC diet) with the highest profits for XG in NC diet. In conclusion, supplementation of 0.02% BM or 0.01% AG or 0.05% XG could improve feed conversion of broilers in corn-soybean meal diet by improving energy utilization and digestive physiology, and also supplementation of 0.05% XG had a preferable efficacy in low energy diet.     

褐马鸡非损伤性取样、微量取样DNA提取的初步研究

褐马鸡是中国特有的国家Ⅰ级保护濒危鸟类,为了解决野生褐马鸡分子生物学研究中存在的取样局限性,采用非伤害性取样和非损伤性取样,对褐马鸡微量血液、皮、脚垫、指甲、羽毛、陈旧标本的皮以及粪便的DNA提取进行了初步研究。结果表明,从褐马鸡微量血液（10μL）中可以提取到浓度和纯度高的基因组DNA（41.85μg）;从褐马鸡的皮、脚垫、指甲、羽毛中可以提取出基因组DNA并扩增出目标片断;陈旧标本的皮能够提取到基因组DNA。该研究将拓宽褐马鸡分子生物学研究的采样范围,并可以提高野外非损伤性取样在保护遗传学中的应用。     

猪链球菌2型四川分离株毒力基因的检测及其序列分析

根据猪链球菌2型的MRP、EPF和SLY基因设计合成了四对引物,对我们分离鉴定的2005四川分离株进行毒力因子检测,并对阳性产物测序比较。结果以分离株为模板,获得了与预期结果一致的867bp(MRP)、572bp(EF)的2个片段,以及SLY的长度为1502bp目的片段(外引物)和1443bp的目的片段(内引物)。说明分离株SSsc0501为MRP+EF+SLY+,属于具有3种主要毒力因子的强毒株。经对PCR阳性产物测序及序列分析,结果其与P1/7株的核苷酸序列完全一致,与1933株的同源性达99.7%,仅在128位、217位、744位、1380位、1386位的5个核苷酸发生突变。在氨基酸水平上SSsc0501株与1933株的同源性达99.6%,有2个氨基酸发生替代。     

丁酸钠在动物生产中的应用研究进展

丁酸钠具有促进动物生长,提高饲料转化效率,抑制肠道病原茵繁殖和提高机体免疫能力等作用.本文就丁酸钠的理化性质、吸收代谢、生物学效应及其在畜禽养殖上的应用等作一阐述.