Methyl donors dietary supplementation to gestating sows diet improves the growth rate of offspring and is associating with changes in expression and DNA methylation of insulin‐like growth factor‐1 gene

The study aimed to investigate the effects of maternal dietary methyl donors on the performance of sows and their offspring, and the associated hepatic insulin‐like growth factor‐1 (IGF‐1) expression of the offspring. A total of 24 multiparous sows were randomly fed the control (CON) or the CON diet supplemented with methyl donors (MD) at 3 g/kg betaine, 15 mg/kg folic acid, 400 mg/kg choline and 150 μg/kg VB₁₂, from mating until delivery. After farrowing, sows were fed a common lactation diet through a 28‐days lactation period and six litters per treatment were selected to be fed until at approximately 110 kg BW. Maternal MD supplementation resulted in greater birthweight (p < 0.05) and increased the piglet weights (p < 0.01) and litter weights (p < 0.05) at the age of day 28, compared with that in CON group. The offspring pigs in the MD group had greater ADG (p < 0.05) and tended to lower F:G ratio (p = 0.07) compared with that of CON group from day 28 to 180 of age. The offspring pigs from MD group had greater serum IGF‐1 concentrations and expressions of hepatic IGF‐1 gene and muscular IGF‐1 receptor (IGF‐1r) protein at birth (p < 0.05), and greater hepatic IGF‐1 protein (p = 0.03) and muscular IGF‐1r gene expressions (p < 0.05) at slaughter, than that from the CON group. Moreover, the methylation at the promoter of IGF‐1 gene in the liver of newborn piglets and finishing pigs was greater in the MD group than that of the CON group (p < 0.05). In conclusion, maternal MD supplementation throughout gestation could enhance the birthweight and postnatal growth rate of offspring, associated with an increased expression of the IGF‐1 gene and IGF‐1r, as well as the altered DNA methylation of IGF‐1 gene promotor.     

Differential gene expression of Eph‐ephrin A1 and LEPR‐LEP with high or low number of embryos in pigs during implantation

The objective of this study was to ascertain whether mRNA and protein expressions of implantation‐related genes (erythropoietin‐producing hepatocellular receptor–ligand A1, Eph‐ephrin A1 and leptin receptor–leptin, LEPR‐LEP) differed between pigs with high and low number of embryos, and whether these differences in gene expression might affect embryo implantation. Experimental pig groups (n = 24) for high and low number of embryos were prepared by altering the number of eggs ovulated in pre‐pubertal gilts treated with 1.5 × (High) or 1.0 × (Low) PG600 ([400 IU PMSG + 200 IU hCG]/dose, AKZO‐NOBEL). Gilts expressing oestrus were artificially inseminated twice and maintained in breeding and gestation until the reproductive tract was collected on day 22 of pregnancy. At slaughter, the reproductive tracts from each pregnant gilt from each treatment were immediately processed to collect samples for RNA and protein analysis. Within each gilt, three conceptus points were sampled, one from each horn and then a random conceptus within the tract. At each conceptus point, endometrial attachment site, chorion–allantois and embryo were collected and immediately frozen in liquid nitrogen. Number of corpus luteum (CL) (35.4 vs. 12.6) and total embryo number (18.8 vs. 10.2) were greater in the high‐embryo compared to the low‐embryo group, respectively (p < .05). Real‐time qPCR results showed that Eph‐ephrin A1 mRNA expression was less in the high‐embryo (p < .05) compared to the low‐embryo group. In addition, Western blotting analysis indicated that Eph‐ephrin A1 and LEP protein expression at endometrial attachment site in high‐embryo was less (p < .05) compared to low‐embryo group. It was also noted that mRNA expression of Eph‐ephrin A1 and LEPR‐LEP was greater in pregnant than non‐pregnant gilts (p < .05). Moreover, mRNA expression of Eph‐ephrin A1 (p < .05) and LEPR‐LEP was greatest at endometrial attachment site among all three tissues. There was a positive correlation between expressions of Eph‐ephrin A1, LEPR‐LEP and embryo length with the correlation coefficient 0.31–0.59. For Eph‐ephrin A1, the highest correlation coefficient appeared between Eph A1 expression and normal embryo number, between ephrin A1 expression and embryo length. For LEPR‐LEP, the highest correlation coefficient appeared between LEPR‐LEP expression and ovary weight (0.79 for both, p < .05), followed by embryo length and weight. The results of this study suggest that low expression of Eph‐ephrin A1 and LEPR‐LEP is somehow related to increased embryo number during implantation and that endometrial attachment site might be the main target tissue of these gene products. Yet, the increased expression of Eph‐ephrin A1 and LEPR‐LEP appeared associated with increased embryo growth (length and weight) and ovary weight, Eph‐ephrin A1 and LEPR‐LEP might play roles in the regulation of embryo implantation in pigs.     

Effects of five cryoprotectants on proliferation and differentiation‐related gene expression of frozen‐thawed bovine calf testicular tissue

The cryopreservation of testicular tissue is a potential method for preserving male fertility. However, the effect of cryopreservation on bovine calf testicular tissue is scarce. This study investigated the effect of different cryoprotectants on bovine calf testicular tissue at the molecular level. Testicular tissue from ten immature bovine calves (6 months) was collected after slaughter and cryopreserved in an extender containing different concentrations of the following five cryopreservation solutions (CP): bovine serum albumin (BSA) with 5% dimethyl sulfoxide (DMSO), trehalose with 5% DMSO, DMSO and glycerol and ethylene glycol (EG). After 7‐day cryopreservation, the expression levels of three spermatogonial stem cell (SSC)‐related genes, octamer‐4 (OCT4), KIT ligand (MGF/SCF) and kit oncogene (C‐KIT), were investigated by quantitative PCR (qPCR). The cell viability was highest for the tissues preserved with 30 mg/ml BSA (77.82% ± 1.22) and 40 mg/ml trehalose (74.23% ± 1.16) compared with other groups (p < 0.05), and the level of expression of the three genes was highest with 30 mg/ml BSA (p < 0.05). Compared with other CPs, the 30 mg/ml BSA and 40 mg/ml trehalose have the better cryopreserve protection. The 30 mg/ml BSA is the most viable media for the cryopreservation of testicular tissue from cattle.     

紫茎泽兰对萨能奶山羊血常规及重要脏器病理学的影响

紫茎泽兰(Eupatorium adenophorum)在中国作为入侵物种,可造成食草动物中毒死亡,并给畜牧业带巨大的损失。为研究反刍动物采食紫茎泽兰后的中毒机理,本研究探讨了日粮中添加不同剂量的紫茎泽兰对萨能奶山羊(Saanen goat)血常规及肝、脾、肾的病理学影响。选择16只5~6月龄健康萨能奶山羊,随机分成对照组(日粮中未添加紫茎泽兰)和试验Ⅰ、Ⅱ、Ⅲ组(日粮配比中分别添加紫茎泽兰40%、60%和80%),每组4只。试验Ⅰ、Ⅱ、Ⅲ组分别饲喂含40%、60%和80%紫茎泽兰的混合日粮3个月,每两周检测一次血常规,试验末屠宰奶山羊,并观察其肝、肾、脾的病理学变化。结果表明,与对照组相比,各试验组血液中的白细胞(white blood cell,)和中性粒细胞(neutrophil,NEUT)均显著升高(P0.05),试验后期极显著高于对照组(P0.01);而各试验组血液中淋巴细胞(lymphocyte,LY)与血红蛋白(hemoglobin,HGB)均呈下降趋势,试验后期均极显著低于对照组(P0.01)。肝和脾肿大,肝组织出现淤血,肝细胞发生水泡变性及脂肪变性等,肾组织伴有出血、坏死、颗粒变性及水泡样变性的现象。因此,本研究结果说明紫茎泽兰对萨能奶山羊血液指标有显著影响,且长期摄入紫茎泽兰可引起动物肝、肾、脾等主要实质器官不同程度的损伤。     

鳢肠对棉铃虫生长发育的影响

通过饲料混毒法测定鳢肠对棉铃虫生长发育的影响。结果表明,随饲料中鳢肠比例的加大和棉铃虫幼虫取食时间的延长,鳢肠对棉铃虫幼虫的生长发育具有明显的抑制作用。幼虫取食鳢肠比例高的饲料后,棉铃虫蛹质量显著降低,但羽化率和单雌日均产卵量与对照处理差异不显著;给棉铃虫幼虫饲喂鳢肠明显延长了幼虫和成虫历期,但对蛹历期的影响较小。     

TFSQ型高效环保组合式粮食杂质清理筛的研制

通过对振动筛理、垂直风选、旋风分离与沉降系统的研究,研制出集振动筛理、风选、旋风分离沉降、含尘气流循环再利用为一体的TFSQ型高效环保组合式粮食杂质清理筛。经应用测试和专家鉴定:该设备具有清理效率高、清理过程粉尘污染小,使用维护方便、可靠性强等优点,具有广阔的市场推广前景。     

Increasing selenium supply during the close-up dry period improves nutrient metabolism and attenuates inflammatory response after calving in dairy cows

The objective of this study was to investigate whether feeding selenium (Se)-replete cows a Se-yeast supplement in late pregnancy affects nutrient metabolism and inflammatory response during the periparturient period. Twenty cows were randomly assigned to two groups with 10 cows each. Cows in one group received Se-yeast at 0.3 mg Se/kg DM during the last 4 weeks before calving in addition to fed a TMR containing supplemented sodium selenite at 0.3 mg Se/kg DM (Se-yeast), while cows in another group were only fed a TMR containing supplemented sodium selenite at 0.3 mg Se/kg DM (Control). Blood samples were collected and analyzed for nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), glucose, insulin, tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, serum amyloid A (SAA), haptoglobin (Hp), and albumin. In control cows, plasma NEFA, IL-1β, IL-6, SAA, and Hp levels increased after calving, but glucose, insulin, and albumin levels decreased after parturition. Se-yeast supplemental cows had lower postpartum concentrations of NEFA, TNF-α, IL-1β, IL-6, SAA, and Hp, and higher postpartum levels of glucose, insulin, and albumin compared with control cows. The results indicate that feeding Se-replete cows a Se-yeast supplement in late pregnancy improves nutrient metabolism and attenuates the inflammatory response after calving.     

产碳青霉烯酶肠杆菌科细菌检测方法研究进展

抗生素的不合理使用使得细菌耐药性快速产生及传播，细菌耐药性已然成为重大公共卫生问题。碳青霉烯类抗生素在临床治疗中表现良好，常作为治疗多重耐药菌感染的最后一道防线，碳青霉烯耐药菌的出现对公共卫生安全产生了极大的威胁。产碳青霉烯酶是碳青霉烯耐药菌耐药的主要机制，因此，对产碳青霉烯酶肠杆菌科细菌的检测至关重要。目前，对于碳青霉烯酶的检测手段以表型检测和分子生物学检测方法为主。表型检测一般易于操作，成本低廉，便于在临床进行，但在检测效率和检测用时方面差强人意。分子生物学及其他新型技术在保持高特异性和敏感性的基础上能做到快速、高通量检测，但试验检测的成本高，需专业设备和人员，部分技术在碳青霉烯酶检测领域仍有待开发。当前，多种碳青霉烯酶的检测方法可针对不同的需求和目的，并没有一项检测能满足所有情况。进行检测时，试验所需时间、操作难度、经济成本等都需列入考量，应根据实际情况选择合适的检测方法。笔者通过结合当前背景，归纳总结产碳青霉烯酶肠杆菌科细菌的检测方法，从试验特异性与敏感性、可操作性、检测时间、试验成本等方面分析比较各个方法特点，以期为之后新的检测方法的开发及现有方法的改良研究提供切入点，为临床监测与检测方案的制定和实行提供思路。