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 change of dry matter intake, milk yield and bone turnover in primiparous cows compared to multiparous cows during early lactation

Data from six primiparous and nine multiparous Holstein cows were used to clarify the difference of Ca and P mobilization between primiparous and multiparous cows during early lactation. The dry matter intake (DMI) of primiparous cows was lower (P < 0.01) than those of multiparous cows. Milk yield was lower in primiparous cows at 7, 14, 21 (P < 0.01), and 28 days (P < 0.05) after parturition. There was no significant difference in milk Ca and P concentrations between primiparous and multiparous cows. There were no significant differences in plasma Ca and P concentrations between primiparous and multiparous cows. The plasma P level at 7 days postpartum in primiparous cows was lower (P < 0.05) than 28 days postpartum. The concentration of plasma osteocalcin (OC) measured as bone formation marker of primiparous cows was significantly higher than multiparous cows (P < 0.01) at 21 and 28 days postpartum. The urinary deoxypyridinoline (DPD) as bone resorption marker of primiparous cows tended to be higher (P < 0.10) than multiparous cows at 21 days after parturition and decreased to the same level as that of multiparae toward the peak lactation. These results show that Ca and P mobilization of primiparous cows are more active than multiparous cows.     

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.     

2019年湖南省部分地区鸡、鸭、猪源大肠杆菌耐药性调查

旨在调查2019年湖南省部分地区不同来源的大肠杆菌对抗生素的耐药水平,为养殖合理用药提供参考。从4个市畜禽养殖场采集猪、鸡和鸭粪便285份,使用麦康凯琼脂培养基和伊红美蓝培养基对大肠杆菌筛选,利用基质辅助激光解析电离飞行时间质谱进行鉴定,采用微量肉汤稀释法检测16种抗生素对大肠杆菌的最小抑菌浓度(MIC)。共分离出203株大肠杆菌(鸡源146株、鸭源20株和猪源37株),对四环素和氨苄西林耐药率最高,分别达到89.2%和84.7%;对头孢他啶、奥格门丁、黏菌素耐药率较低,分别为2.5%、2.0%和0.5%;所有菌株均对美罗培南敏感。抗3种及以上抗生素的菌株数目占比为87.7%,而仅5.42%的菌株对所有检测的抗生素敏感。另外,来源于减抗示范养殖场的大肠杆菌对大部分抗生素的耐药率,与来源于非减抗养殖场大肠杆菌相比未见显著差异。上述结果表明,湖南省动物源大肠杆菌的耐药水平仍处在较高水平,重视兽药使用管理并持续开展对大肠杆菌的耐药性监测十分必要。     

Genetically engineered animal models for Marfan syndrome: challenges associated with the generation of pig models for diseases caused by haploinsufficiency

Recent developments in reproductive biology have enabled the generation of genetically engineered pigs as models for inherited human diseases. Although a variety of such models for monogenic diseases are currently available, reproduction of human diseases caused by haploinsufficiency remains a major challenge. The present study compares the phenotypes of mouse and pig models of Marfan syndrome (MFS), with a special focus on the expressivity and penetrance of associated symptoms. Furthermore, investigation of the gene regulation mechanisms associated with haploinsufficiency will be of immense utility in developing faithful MFS pig models.     

猪肺疫的诊断与防治

从病原、流行病学、症状、病理变化、实验室检验、类症鉴别及防治技术等方面,综合阐述了猪肺疫的诊治要点。     

猪活动区域多孔介质模型及其阻力系数的CFD模拟

旨在尝试将躺卧姿势下的猪体简化成不同几何形状以求取其阻力系数,并分析它们的差异性.本研究采用校核过的CFD模型,模拟探究了简化猪模型、半椭球模型、椭球模型和半圆柱模型4种不同躺卧猪模型对猪群区域在X、Y和Z3个垂直方向上阻力系数的影响,分析了4种模型对猪栏内气流以及压力分布的影响.结果 表明,椭球模型的惯性阻力系数相比...