Energy and protein requirements for maintenance of Hu sheep during pregnancy

This study aimed to determine the effect of stage and level of feed intake on energy metabolism,carbon-nitrogen(C-N)balance,and methane emission to determine energy and protein requirements for maintenance of maternal body including pregnancy tissues during pregnancy using the method of C-N balance.Twenty-one ewes carrying twin fetuses were randomly divided into three groups of seven ewes each in the digestion and respirometry trial at d 40,100,and 130 of gestation,respectively.Three groups were fed a mixed diet either for ad libitum intake,70 or 50%of the ad libitum intake during pregnancy.The results showed that the apparent digestibility of C and N were increased as feeding levels decreased at each stage of gestation.The daily net energy requirements for maintenance(NE_m)were 295.80,310.09,and 323.59 k J kg~(–1)BW~(0.75)(metabolic body weight)with a partial efficiency of metabolisable energy utilization for maintenance of 0.664,0.644,and 0.620 at d 40,100,and 130 of gestation,respectively.The daily net protein requirements for maintenance were 1.99,2.35,and 2.99 g kg~(–1 )BW~(0.75) at d 40,100,and 130 of gestation,respectively.These results for the nutritional requirements of the net energy and protein may help to formulate more balanced diets for Hu sheep during pregnancy.     

薄型子宫内膜的中西医研究进展

目的 探究薄型子宫内膜的病因机制，分析临床现行的处理策略，加深对薄型子宫内膜的认识，更好地指导临床工作。方法 整理、分析最新薄型子宫内膜的中西医研究文献成果。结果 当代医学对薄型子宫内膜病因机制阐述颇多，处理策略多样，但均存在一定局限性，还未形成统一的治疗原则。中医治疗多以补肾活血为大法，显示出较好的优势。结论 学者对薄型子宫内膜病因的认知尚未形成共识，发病机制仍不明确，治疗效果各异。中西医治疗各有优势，较西医治疗，中药、针灸具有多靶点整合，整体网络调节等优点，成效显著，值得临床推广应用。     

Different origins of two corpora lutea recovered from a pregnant African elephant (Loxodonta africana)

Elephant ovaries contain multiple corpora lutea (CLs) throughout pregnancy. Two CLs (P‐1 and P‐2) collected from a pregnant African elephant were used to investigate their origin and physiological state in this study. The mRNA expressions of prolactin receptor, CYP11A and inhibin betaB subunit were higher in P‐2 than in P‐1, while LHCGR and inhibin betaA subunit mRNA were higher in P‐1 than in P‐2. Protein expression of cleaved caspase‐3 was detected in P‐1 but not in P‐2. These results suggest different origins for the two CLs in this one pregnant elephant, and we also demonstrated the production of bioactive prolactin by the elephant placenta.     

奶牛早孕因子重组蛋白的原核表达、纯化及多克隆抗体的制备

本研究旨在表达、纯化奶牛早孕因子重组蛋白及制备多克隆抗体。本试验构建奶牛早孕因子重组蛋白原核表达载体pET32a-EPF,转化至大肠杆菌BL21(DE3)内进行诱导表达,SDS-PAGE切胶纯化的早孕因子重组蛋白免疫BALB/c小鼠制备多克隆抗体,并用Western blotting和ELISA对重组蛋白及抗体进行检测。结果显示,成功表达并纯化了奶牛早孕因子重组蛋白,重组蛋白分子质量约37ku,表达量约占菌体总蛋白的48.6%,纯化后目的蛋白纯度可达93%,重组蛋白可与所制备的多克隆抗体结合,ELISA测定的抗体效价为1∶12 800。结果表明,本研究成功表达并纯化了奶牛早孕因子重组蛋白,为研究奶牛早孕诊断奠定基础。     

Fertility of Holstein cows and heifers submitted to timed artificial insemination and receiving one or two doses (12 h apart) of semen

The objective of this retrospective study was to assess the effect of receiving a single (n = 50,285) or double (n = 4392) artificial insemination (AI), 12 h apart, within a timed artificial insemination protocol on pregnancy per AI (P/AI) in nulliparous heifers (inseminated with either sex-sorted or conventional semen) and pluriparous Holstein cows in a commercial dairy herd. Also, this study aimed to investigate the relationship between temperature-humidity index (THI) and time of the first AI and fertility. Fertility of cows receiving two AI with normothermia (THI <68) was higher (p < .05) than cows receiving a single AI (42.9% vs. 36.4%). P/AI of cows receiving two AI with severe heat stress (THI >85) was higher (p < .05) than cows receiving a single AI (21.0% vs. 12.6%). Regardless of heat stress conditions, applying the first AI in the morning increased (p < .05) P/AI in cows with double AI than in cows whose first AI occurred in the afternoon (38.4 vs. 33.3%). With moderate heat stress, and sexed-sorted semen, P/AI to timed AI was higher (65.0 vs. 51.9%; p < .05) in heifers receiving double AI than those serviced once. It was concluded that double AI, 12 h apart, enhanced fertility at timed AI than herd mates with a single AI, particularly with heat stress at breeding.     

Current knowledge about the processes of luteolysis and maternal recognition of pregnancy in camelids

Camelids have many unique reproductive features that considerably differ from those of other domestic species. Females are induced ovulators with subsequent development of a corpus luteum (CL) with a short lifespan. Plasma progesterone concentration starts to increase on day 4, peaks on day 8–9 and, in non-pregnant animals, basal concentration is reached around day 10–11 post-induction of ovulation. Luteolytic pulses of prostaglandin F_2α (PGF_2α) are firstly detected on day 7 or 8 (approximately on day 5–6 after ovulation), with maximal luteolytic peaks observed between days 9 and 11 post-mating, in coincidence with a high endometrial expression of cyclooxygenase 2, a limiting enzyme in prostaglandins synthesis. Unlike other species, oxytocin seems not to be involved in the luteolytic process in these species. The CL is the main source of progesterone secretion, and its function is required to support pregnancy. Despite constant research efforts, aspects of reproduction and maternal recognition of pregnancy in camelids remain not fully understood. A transient decrease and subsequent recovery in plasma progesterone concentration are observed after day 9 post-mating in pregnant animals in association with a pulsatile release of PGF_2α and a transitory decrease in CL vascularization. Thus, embryo recognition should occur between days 8 and 12 post-mating. In camels, conceptus tissues exhibit aromatizing activity with the capacity to synthesize large amounts of oestradiol. Similarly, llama blastocysts secrete oestradiol-17β during the preimplantation stage, with a higher production during the elongation period. An increase in the endometrial expression of oestrogen receptor α is also observed on day 12 post-mating. All these evidences suggest that oestrogen could be the signal released by the embryo at the time of its recognition in camelids. Besides, nearly 98% of pregnancies are carried out in the left horn. A decrease in the endometrial expression of mucin 1 and 16 genes has been reported, suggesting that these changes are crucial for successful embryo implantation; however, no differences have been observed between horns. Thus, maternal recognition of pregnancy in camelids is a particularly complex process that must occur in a concise time to allow the rescue of the CL and embryo survival.     

饲粮添加脯氨酸对妊娠环江香猪体成分的影响

本试验旨在研究饲粮添加脯氨酸对妊娠环江香猪体成分的影响。选取32头妊娠15 d的环江香猪,随机分为2组,每组8个重复,每个重复2头猪。2组试验猪分别饲喂在基础饲粮中添加0.77%L-丙氨酸(等氮对照组)和1.00%L-脯氨酸(脯氨酸组)的饲粮。分别于妊娠第45和70天时,每个重复选择1头母猪屠宰,测定其体成分。结果表明:与等氮对照组相比,妊娠第45天时脯氨酸组环江香猪的脂肪率显著降低(P0.05),皮肤率呈增加趋势(0.05≤P0.10);妊娠第70天时脯氨酸组的脂肪率显著增加(P0.05),皮肤率呈降低趋势(0.05≤P0.10),背最长肌中脯氨酸的含量显著增加(P0.05),精氨酸和丙氨酸的含量呈增加趋势(0.05≤P0.10)。与妊娠第45天时相比,妊娠第70天时脯氨酸组的脂肪率显著增加(P0.05),瘦肉率与皮肤率显著降低(P0.05)。由此可见,饲粮添加脯氨酸可增加妊娠环江香猪机体脂肪和精氨酸的沉积量,妊娠中期的机体脂肪沉积量比妊娠前期有所增加,从而有利于胎儿的生长发育。     

羊超声波早期妊娠诊断技术的研究

结合生产实践,采用超声波仪对羊进行了早期妊娠诊断技术的应用研究试验。结果表明：发情配种后35 d以上的母羊可以采用超声波仪确定其是否怀孕,准确率接近于100%。这种方法不仅可以及时将妊娠母羊隔离饲养,而且能够对未妊娠母羊及时补配或淘汰,降低饲养成本。     

壳寡糖对妊娠后期母猪免疫功能和仔猪初生重的影响

[目的]研究饲粮中添加壳寡糖对妊娠后期母猪免疫功能和仔猪初生重的影响,并探讨壳寡糖的适宜添加量。[方法]选择健康的、体重和预产期相近的四胎次"长×大"母猪35头,随机分为5组,每组7个重复,每个重复1头母猪。对照组饲喂基础饲粮(不添加壳寡糖),试验组Ⅰ、Ⅱ、Ⅲ、Ⅳ在基础饲粮中分别添加壳寡糖30、90、270和810 g/t。试验从母猪妊娠85 d开始,至产仔结束。[结果]饲粮中添加壳寡糖对仔猪初生重、母猪血清白介素2(IL-2)浓度和补体C3蛋白浓度均无显著影响(P0.05)。饲粮添加不同水平的壳寡糖显著提高母猪血清中溶菌酶的浓度(P0.05)。饲粮中添加不同水平的壳寡糖显著提高母猪血清猪瘟抗体sIgA的浓度(P0.05),而试验组Ⅰ和Ⅱ初乳中猪瘟抗体sIgA浓度无显著差异(P0.05),试验组Ⅲ和Ⅳ初乳母源猪瘟抗体sIgA浓度显著提高(P0.05)。[结论]妊娠后期母猪饲粮中壳寡糖的适宜添加量为270 g/t。     

Birth of puppies of predetermined sex after artificial insemination with a low number of sex‐sorted,frozen–thawed spermatozoa in field conditions

The aim of this study was to evaluate fertility and sex ratios after artificial insemination in dogs under field conditions. Semen was cryopreserved as unsorted (control) or was separated into X‐ and Y‐chromosome‐bearing sperm using a cell sorter. Sixty female dogs were inseminated with frozen–thawed spermatozoa of 100 × 10⁶ unsorted (a dose in practice) and 4 × 10⁶ sorted (X and Y group, respectively). A total of 20 dogs became pregnant and 126 puppies were born from the three groups. The percentage of parturition was similar for the X (5/20; 25.0%) and Y (4/20; 20.0%) group (P > 0.05), but lower than controls (11/20; 55.0%) (P < 0.05). Ultimately 28 out of the 32 puppies produced from X group were female (87.5%) and 19/22 (86.4%) puppies of Y group were male. In contrast, sex ratio (51.4% to 48.6%) in the control was significantly different from the X, Y group (P < 0.05). However, male and female puppies in the control had similar birth weights and weaning weights to those from the X and Y groups. This preliminary information indicated that normal puppies of predicted sex can be produced with low numbers of sorted cryopreserved dog spermatozoa at a farm level, making sperm‐sexing technology potentially applicable for elite breeding units.