猪胚胎死亡的影响因素及其预防措施

猪胚胎死亡直接影响着母猪的产仔数，并进而影响着养猪生产的经济效益。因此，在深入研究猪胚胎死亡规律及其影响因素的基础上，通过有效的措施降低胚胎死亡率，对提高母猪窝产仔数和经济效益具有十分重要的意义。本文综述了影响猪胚胎死亡的遗传、环境、营养和疾病等因素，并对生产实践中如何通过综合预防措施降低猪胚胎死亡率进行了初步探讨。     

乳猪体内糖类的消化和吸收研究

乳猪小肠内葡萄糖的分布状况既与饲料的碳水化合物种类和数量相关，也与小肠的不同部位相关，十二指肠段和空肠段分别是乳糖、淀粉类碳水化合物分解和葡萄糖吸收的主要部位血糖浓度离肝脏越远含量越低，而与饲料中糖类含量的多少无关。     

The effect of maternal obesity on fatty acid transporter expression and lipid metabolism in the full‐term placenta of lean breed swine

This study was conducted to evaluate the influence of back‐fat thickness (BF), at mating of sows, on the maternal and newborn circulating lipids, expression of placental fatty acids (FA) transporters and lipid accumulation in placenta. Full‐term placentas were obtained by vaginal delivery from BFI (9–14 mm; n = 37), BFII (15–19 mm; n = 43) and BFIII (20–27 mm; n = 38) sows according to BF at mating, and frozen placental sections were analysed for fat accumulation. Blood samples were collected from the sows of day 105 pregnancy and from cord blood at delivery. mRNA and protein expression levels were evaluated with real‐time RT‐PCR and Western blotting. Our results demonstrated that BFII females had significantly increased litter weight and placental efficiency, decreased maternal triglyceride (TG) and non‐esterified fatty acids (NEFA) levels, decreased maternal IL‐6, TNFα and leptin levels compared to BFIII females (p < .05). BFIII sows were associated with significantly decreased newborn TG levels, increased newborn glucose, IL‐6 and TNFα levels compared to BFI or BFII sows (p < .05). BFI and BFII females had significantly decreased placental TG, NEFA and cholesterol (CHOL) contents compared to BFIII females (p < .05). Moreover, decreased CD36, FATP1, FABP4, and FABP1 mRNA and protein and FATP4 protein expression, and increased LPL activity were also observed in BFIII group compared with BFII group (p < .05). PPARγ mRNA and protein and lipogenic genes such as SREBP‐1c, ACSL1, ACCα, FAS and SCD mRNA expression were downregulated or upregulated, respectively, in the placentas of BFIII sows compared to BFI or BFII sows (p < .05). Overall, this study demonstrated that there is no advantage, in terms of litter live size, litter weight and placental FA transport and metabolism, in performing the mating of sows with BF>19 mm.     

Effects of a DHA‐rich unextracted microalgae as a dietary supplement on performance,carcass traits and meat fatty acid profile in growing‐finishing pigs

Two 125‐day experiments of the same design were conducted to evaluate the effects of a heterotrophically grown microalgae (AURA) containing docosahexaenoic acid (DHA) on pig performance, carcass traits and the fatty acid composition of lean and adipose tissue. In each experiment, 144 Hypor pigs were blocked by sex, allocated to three treatment groups, and fed 0, 0.25% or 0.50% AURA in isonutritive, isocaloric diets. Pigs were weighed on days 0, 28, 56, 84 and 112. Feed and water intakes were measured every 28 days. Pigs were slaughtered on day 125. Data from the two studies were analysed as a single data set. Performance and carcass traits did not differ between treatments. Both microalgae treatment levels enriched (p < .05) Longissimus lumborum (LL) and backfat in DHA and improved (p < .05) their ratios of n‐6 to n‐3 fatty acids.     

百宜黑羽鸡外貌特征及生长发育研究

从选育中的1,2世代百宜黑羽鸡的外貌特征、生长性能两个方面对百宜黑羽鸡的部分特征特性进行了研究,结果表明:百宜黑羽鸡具有全黑羽带墨绿色(脚、胫、喙、耳毛为黑色),体形中等,肤白色。2周龄时公母均出现日增重率先升后降,分别由0.048%和0.48%上升到41.72%和37.79%,接着又下降到5.69%和5.06%。百宜母鸡的生长曲线从10周龄开始与公鸡的生长曲线分离,17周龄后母鸡的生长速度明显慢于公鸡。     

猪附红细胞体生物学特性的研究

采取新鲜血液压片相衬观察和末梢血液涂片染色镜检法,对河南省新乡地区3000头猪附红细胞体病发病情况进行了调查;并且对体温升高、镜检附红细胞体感染强度为 病猪的血液,分别用光学显微镜、扫描电子显微镜进行形态观察和血液生化指标检测.结果表明:猪附红细胞体病的发病率为46.33%,死亡率为13.88%,隐性感染率为55.93%(755/1350).在光学显微镜下观察,红细胞呈现菠萝样;染色血片观察附红体在红细胞表面及边缘呈各种形式排列,可见强折光性发亮的圆形小体;扫描电子显微镜观察.附红体寄生的红细胞凹陷区,有大、小球体,有的小球体与大球体相连.血清胆红素、白蛋白、尿素氮、谷丙转氨酶、谷草转氨酶增加,血糖、血清总蛋白、超氧化物歧化酶活性下降.     

高坡猪GH基因不同基因型对其部分生产性能的影响

采用PCR-RFLP-ApaⅠ方法检测高坡猪GH基因-119~ 486 bp片段的多态性,探讨了不同基因型对其部分生产性能的影响。结果表明:产生2个等位基因A(449 bp)和B(316 133 bp),其频率分别为0.54和0.46;3种基因型:AA、AB和BB,其频率分别为0.26、0.56和0.18;除6月龄腹围和背膘厚外,其余指标值均以BB基因型最高,AA基因型的6月龄腹围和瘦肉率与BB基因型相比差异显著(P<0.05),其他指标在各基因型间差异均不显著(P>0.05)。表明,A可能是小型猪的有利等位基因,B则可能是大型猪的有利等位基因。     

长期不同施氮量下黑土团聚体稳定性及有机碳含量的变化

为测定不同氮肥施用量对黑土团聚体组成及稳定性、有机碳含量及团聚体有机碳分布的影响,阐明黑土有机碳稳定性对不同施氮水平的响应机制,本研究在吉林省梨树县不同施氮水平长期定位试验田进行取样,以施氮水平不同设置5个处理,分别为T1(0)、T2(160 kg·hm^-2)、T3(240 kg·hm^-2)、T4(280 kg·hm^-2)、T5(320 kg·hm^-2),分析长期不同施氮量下水稳性团聚体组成、团聚体结构特征、土壤总有机碳含量及团聚体有机碳分布的变化,探究酸化黑土有机碳含量影响特征。结果表明：随氮肥施用水平的升高,土壤碱解氮(AN)和全氮(TN)含量先增后减,T3处理含量最高,AN和TN分别比T1处理高24.90%、10.28%;土壤速效磷(AP)的含量呈下降趋势。随氮肥用量的提高,土壤团聚体呈现大粒径团聚体向小粒径团聚体转变的趋势,>2 mm粒径团聚体下降14.55%。土壤有机碳总量随施氮水平的提高呈先增后减的趋势,施氮量为280 kg·hm^-2有机碳含量最高;>2...     

LC-MS/MS法分析生猪异位发酵床垫料中5大类兽用抗菌药物残留及蓄积趋势

建立了生猪异位发酵床垫料中四环素类、喹诺酮类、磺胺类、酰胺醇类和大环内酯类共54种抗菌药物残留量的LC-MS/MS检测方法.经超低温冷冻粉碎后的垫料样本,费休氏-库仑滴定法测定水分,Mcllvaine-Na2 EDTA缓冲液和乙腈提取,亲水亲脂平衡固相萃取小柱净化,LC-MS/MS法测定抗菌药物残留量,最终结果以折水后...     

攀西黑山羊群体的AFLP遗传多样性研究

 研究采用随机片段长度多态性分析了攀西地区的5个黑山羊品种（类群）的遗传多样性。结果表明：15对引物共扩增出1003条多态条带,多态频率平均为99.01%,5个黑山羊群体的遗传多样性指数变异范围为0.0136~0.2131,其中建昌黑山羊平均遗传多样性指数最高（0.1346）,攀枝花黑山羊次之（0.1329）,乐至黑山羊最低（0.1101）。5个群体遗传距离范围为0.0062~0.0281,攀枝花黑山羊与建昌黑山羊之间的遗传距离最小（DR=0.0062）,云岭黑山羊与攀枝花黑山羊之间的遗传距离次之（DR=0.0128）,乐至黑山羊与金堂黑山羊间遗传距离最大（DR=0.0281）,金堂黑山羊与其它4个类群遗传距离较大（DR=0.0173-0.0281）,说明攀枝花黑山羊与建昌黑山羊的亲缘关系最近,与云岭黑山羊的亲缘关系较近,乐至黑山羊与金堂黑山羊的亲缘关系最远,金堂黑山羊与其它4个类群遗传距离均比较远。聚类结果与群体地理分布、生态条件差异情况基本一致。