妊娠早期饲粮中添加N-氨甲酰谷氨酸对母羊早期胚胎存活及相关血液指标的影响

本试验旨在研究妊娠早期饲粮中添加N-氨甲酰谷氨酸（NCG）对母羊胚胎存活及相关血液指标的影响,并对其作用机制进行初步探讨。选择发情正常、健康状况良好的湖羊50只,随机分为2组（对照组和NCG试验组）,每组25只母羊,自配种当天开始给母羊分别饲喂基础饲粮（对照组）和基础饲粮+0.11%NCG（NCG组）,饲喂期38 d。测定妊娠第19和38天母羊血浆游离氨基酸、总一氧化氮合酶（TNOS）、内皮型一氧化氮合酶（eNOS）、诱导型一氧化氮合酶（iNOS）、一氧化氮（NO）、雌二醇、孕酮的浓度;38 d时每组各屠宰7只妊娠母羊,测定妊娠母羊的黄体数和活胎儿数等指标。结果显示,与对照组相比,妊娠第38天时,NCG组每只母羊总胎儿数增加了79.72%（P<0.05）,活胎儿数增加了79.72%（P<0.05）,胎儿形成指数增加了0.26（P<0.05）,胎水体积增加了72.89%（P<0.05）,活胎儿总重提高了71.13% （P<0.05）;NCG组妊娠第19天的甘氨酸、蛋氨酸、赖氨酸、精氨酸、NO、iNOS、eNOS和孕酮的浓度显著高于对照组（P<0.05）,NCG组妊娠第19天的瓜氨酸和脯氨酸极显著高于对照组（P<0.01）;NCG组妊娠第38天的精氨酸、脯氨酸和NO显著高于对照组（P<0.05）,NCG组妊娠第38天的iNOS和eNOS的浓度极显著高于对照组（P<0.01）。由此,妊娠早期饲粮中添加NCG提高了胚胎和胎儿的存活,增加了妊娠母羊第38天的总胎儿数和活胎儿数,改善了母羊的繁殖性能,其作用机制可能是NCG促进了母羊内源性精氨酸的合成,提高了母羊血浆精氨酸、NO和孕酮含量,改善了子宫内环境和营养供给,使之有利于胚胎着床和妊娠维持。     

日粮中添加NCG对妊娠前期鄂尔多斯细毛羊子宫内膜层及胎儿发育的影响

为了研究日粮中添加N-氨甲酰谷氨酸(NCG)对妊娠前期鄂尔多斯细毛羊子宫内膜层及胎儿发育的影响,试验选择受孕鄂尔多斯细毛羊母羊40只,随机分为3组:NCG1组饲喂基础日粮+0.30 g NCG/d(n=13),NCG2组饲喂基础日粮+0.40 g NCG/d(n=13),对照组饲喂基础日粮(n=14),开展妊娠期0 d至90 d的饲喂试验。结果表明:妊娠期第90 d,NCG1组胎儿肺脏重显著高于对照组,NCG2组胎儿肝脏重显著高于对照组(P0.05);妊娠期第17天,NCG1组母羊子宫内膜OPN基因表达量显著高于NCG2组(P0.05)和对照组(P0.01),NCG2组母羊子宫内膜Integrinαvβ3基因表达量显著高于对照组(P0.05);妊娠期第90 d,NCG2组和NCG1组胎儿肾脂肪BMP7(P0.05)和UCP-1基因表达量显著高于对照组(P0.01),而NCG1组(P0.01)胎儿肾脂肪PGC-1α基因表达量显著低于对照组,NCG2组(P0.01)胎儿肾脂肪PRDM16基因表达量显著低于对照组。在本试验条件下,妊娠前期日粮中添加NCG有效促进了鄂尔多斯细毛羊妊娠识别、早期胚胎定植和子宫内膜层发育,保障了胎儿早期程序化健康生长。     

胆酸负荷对妊娠后期绵羊母体和胎儿血浆IGF—2及其代谢物水平的影响

以绵羊及其胎儿为试验对象，研究了胆酸负荷对妊娠后期母体和胎儿血浆胰岛素样生长因子－2(in-sulin-like growth factor-2,IGF-2）及其代谢物水平的影响。将7只确知妊娠时间的绵羊分为试验组5只和对照组2只，试验前装置颈静脉瘘，在妊娠90h和104d2闪给试验组静脉灌注胆酸盐1．1mg/kg，给对照组静脉灌注等量生理盐水，妊娠120d时手术安装胎儿后肢胫前动脉血管瘘。每天采胎儿和母体的血样，分离血浆，测定血浆IGF－2和主要代谢物水平。同时测定胎儿出生时生长发育指标。结果表明：（1）试验组母羊IGF－2水平低于对照组，相反其胎儿IGF－2水平却高于对照组（P＜0．05）；（2）试验组母羊的总蛋白和乳酸水平分别比对照组35．64％；（3）试验组胎儿出生重比对照组小29．00％，胎龄短7．50d。因此认为，胆酸重复灌注可引起妊娠绵羊早产和胎儿出生重降低，而这可能与IGF－2和主要代谢物水平变化有关。     

日粮中添加NCG对妊娠前期鄂尔多斯细毛羊血液、尿囊液和羊水中氨基酸浓度的影响

为了研究日粮中添加NCG(N-氨甲酰谷氨酸)对妊娠前期鄂尔多斯细毛羊血液、尿囊液和羊水中氨基酸浓度的影响,试验选择年龄、胎次和体况相近、平均体重为50.62±0.52 kg的受孕鄂尔多斯细毛羊母羊40只,随机分为3组(NCG1组饲喂基础日粮+0.30 g NCG/d(n=13),NCG2组饲喂基础日粮+0.40 g N...     

节律性日粮对鄂尔多斯细毛羊泌乳性能和血液指标的影响

研究节律性日粮对鄂尔多斯细毛羊母羊泌乳中后期泌乳量、乳成分和血液指标及羔羊生长发育的影响。选择体况良好,平均体重为(39.34±2.58)kg的泌乳中后期鄂尔多斯细毛羊母羊30只,随机分为3组,每组10只,分别为对照组、高-低蛋白组和低-高蛋白组,进行为期60 d的节律性蛋白日粮饲喂试验。结果表明,泌乳期60 d高-低蛋白组试验母羊和90日龄高-低蛋白组羔羊的平均体重显著高于对照组(P0.05),整个试验期高-低蛋白组试验母羊和羔羊的平均日增重均显著高于对照组(P0.05);泌乳期45 d高-低蛋白组试验母羊乳脂肪含量显著高于对照组(P0.05),泌乳期60 d高-低蛋白组试验母羊的平均泌乳量和乳蛋白含量显著高于对照组(P0.05);泌乳期60 d和90 d高-低蛋白组试验母羊血液中葡萄糖浓度显著高于低-高蛋白组和对照组(P0.05)、总蛋白的浓度显著高于对照组(P0.05),泌乳期60 d高-低蛋白组试验母羊血液中胰高血糖素浓度显著高于低-高蛋白组和对照组(P0.05)。在本试验条件下,节律性饲喂不同蛋白浓度日粮不仅可以有效提高细毛羊泌乳中后期母羊体重、日增重、泌乳量、乳脂肪和乳蛋白的含量,而且促进羔羊的快速生长和发育,泌乳中后期鄂尔多斯细毛羊更适合高-低蛋白节律性饲喂方式。     

妊娠后期营养限饲对蒙古绵羊体贮动员及其胎儿生长发育的影响

本试验旨在研究妊娠后期营养限饲对蒙古绵羊体贮动员及其胎儿生长发育的影响。选择健康的蒙古绵羊35只(经同期发情受孕),在妊娠90 d时选择6只母羊进行屠宰,其余按体重随机分为3组,分别为自由采食组[C组,代谢能(ME)日均采食量为0.670 MJ/(kg W0.75.d),n=8]、限饲1组[R1组,ME日均采食量为0.175 MJ/(kg W0.75.d),n=12]、限饲2组[R2组,ME日均采食量为0.330 MJ/(kg W0.75.d),n=9],试验至妊娠140 d结束,每组再选择6只母羊进行屠宰。结果表明:妊娠140 d,R1组母体净失重,胴体重,肉中干物质、粗脂肪、粗蛋白质、粗灰分含量,血浆葡萄糖(GLU)、总氨基酸(TAA)浓度极显著低于C组(P<0.01),而非酯化脂肪酸(NEFA)、β-羟丁酸(BHBA)浓度极显著高于C组(P<0.01);R2组母羊净失重,胴体重,肉中干物质、粗脂肪含量及血浆GLU、TAA浓度极显著低于C组(P<0.01),而血浆NEFA浓度极显著增加(P<0.01)。母羊失重导致R1组和R2组胎儿重均极显著低于C组(P<0.01),而且R1组体长(P<0.05)、胸围(P<0.05)、腹围(P<0.05)和曲冠臀长(P<0.01)显著或极显著低于C组。总之,妊娠后期随着营养水平的降低,限饲ME日均采食量为0.330 MJ/(kg W0.75.d)时,母体的缓冲保护系统仍对胎儿有一定的作用,而继续限饲至ME日均采食量为0.175 MJ/(kg W0.75.d)时,母体的营养缓冲系统可能已被打破,严重影响到其胎儿的生长发育。     

围产期补喂L-精氨酸对伊犁马母马血液参数、妊娠率、返情率及新生马驹生长的影响

本试验旨在探讨在妊娠期最后21 d和分娩后25 d期间补喂L-精氨酸对伊犁马母马血液参数、新生马驹生长以及母马分娩后配种妊娠率与返情率的影响。试验选择30匹年龄、体重、体高、预产期相近的伊犁马母马,分为2组,分别为对照组(n=15)和L-精氨酸组(n=15)。对照组饲喂基础饲粮,L-精氨酸组在基础饲粮配方的基础上添加0.5%L-精氨酸,使每匹马每天L-精氨酸的补喂量达到60 g。母马分娩后12 h内测定马驹体重、体尺参数并统计分娩后配种妊娠率、返情率,同时于试验第0(补喂试验开始前)、21、45天采集母马静脉血样。结果显示:与对照组相比,L-精氨酸组新生马驹体重、体尺参数、母马分娩后配种妊娠率无显著差异(P0.05),母马分娩后配种返情率显著降低(P0.05)。与对照组相比,L-精氨酸组母马试验第21天血浆总一氧化氮合成酶(TNOS)、内皮型一氧化氮合成酶(eNOS)活性与一氧化氮(NO)含量无显著差异(P0.05);试验第45天血浆TNOS活性显著降低(P0.05),NO含量极显著降低(P0.01),eNOS含量无显著差异(P0.05)。与对照组相比,L-精氨酸组母马试验第21天血浆氨(NH_3)、尿素氮(UN)含量无显著差异(P0.05);试验第45天血浆NH_3含量极显著降低(P0.01),UN含量无显著差异(P0.05)。与对照组相比,L-精氨酸组母马试验第21、45天血浆生长激素(GH)、胰岛素样生长因子-Ⅰ(IGF-Ⅰ)、胰岛素(INS)含量均无显著差异(P0.05)。结果提示,伊犁马母马围产期补喂L-精氨酸可改变母马体循环血浆TNOS活性与NO、NH_3含量,同时降低母马分娩后配种返情率,但对新生马驹体重、体尺参数、分娩后配种妊娠率无显著影响。L-精氨酸可作为营养调控剂,用于母马的妊娠最后期营养补充或分娩后护理以改善母马的繁殖力。     

妊娠早期饲粮添加不同水平N-氨甲酰谷氨酸改善母羊产羔性能的研究

旨在研究妊娠早期饲喂不同水平N-氨甲酰谷氨酸(N-carbamylglutamate,NCG)对母羊产羔性能及相关血液指标的影响。选用2～3胎次湖羊160只,随机分为4组,每组40只母羊,自配种当天(记为妊娠第0天)开始,分别饲喂基础饲粮(对照组)、基础饲粮+0.05%NCG、基础饲粮+0.08%NCG、基础饲粮+0.11%NCG,40 d后均饲喂基础饲粮。测定母羊产羔性能和妊娠第0、20、40天母羊血浆中游离氨基酸、总一氧化氮合酶(TNOS)、诱导型一氧化氮合酶(iNOS)、一氧化氮(NO)、生长激素、雌二醇、孕酮、尿素和氨浓度。结果显示,0.08%和0.11%NCG组产羔性能显著提高,两组的窝产羔数和窝产活羔数较对照组显著增加(P0.05),但活羔初生个体重显著降低(P0.05);各NCG组妊娠第40天NO浓度显著升高(P0.05),0.11%NCG组妊娠第40天iNOS浓度和妊娠第20天孕酮浓度较对照组显著升高(P0.05);0.08%和0.11%NCG组妊娠第20天氨浓度显著低于对照组和0.05%NCG组(P0.05),0.11%NCG组妊娠第40天氨浓度显著低于对照组(P0.05)。综上,妊娠早期母羊饲粮添加NCG可提高母羊体循环iNOS、NO和孕酮浓度,改善胎盘营养与妊娠维持状态;降低血浆氨浓度,提高胎儿发育环境安全性,改善母羊产羔性能,提高母羊窝产羔数和窝产活羔数。     

5-羟色胺对围产期母羊生产性能及血浆和乳中钙转运相关生化指标的影响

本试验旨在研究5-羟色胺(5-HT)对围产期母羊生产性能及血浆和乳中钙转运相关生化指标的影响。试验选用30只巴美肉羊母羊,按体重随机分为3组,分别为对照组、5-羟基色胺酸(5-HTP)组(灌注5-HTP)和色氨酸(Trp)组(灌注Trp),每组10只。在母羊围产期产前第7天至产后第0天,进行颈静脉灌注,5-HTP和Trp的灌注剂量均为0.178 mg/kg BW,浓度为0.1 mg/mL;对照组灌注同等剂量的生理盐水。试验期为产前第7天至产后第30天。结果表明:1)各组间母羊体重无显著差异(P>0.05)。产后第5、9和15天,Trp组母羊泌乳量均低于对照组(P>0.05);产后第9和15天,5-HTP组母羊泌乳量均高于对照组(P>0.05)。产后第16~30天,5-HTP组羔羊平均日增重显著高于对照组(P<0.05)。2)产后第15天,Trp组血浆和乳中钙浓度显著高于对照组(P<0.05);产后第3、6和15天,5-HTP组血浆和乳中钙浓度显著高于对照组(P<0.05)。产后第6天,Trp组血浆5-HT浓度显著高于对照组(P<0.05);产后第30天,Trp组乳中5-HT浓度显著高于对照组(P<0.05);产后第6、9和30天,5-HTP组血浆和乳中5-HT浓度显著高于对照组(P<0.05)。产后第3、6和15天,Trp组和5-HTP组血浆甲状旁腺素相关蛋白(PTHrP)浓度均显著高于对照组(P<0.05)。由此可见,灌注5-HTP可以促进母羊泌乳,提高羊羔平均日增重;灌注5-HTP和Trp可以增加血浆和乳中钙、5-HT浓度及血浆PTHrP浓度。     

5-羟色胺前体物对围产期母羊泌乳性能及血浆生化指标的影响

本试验旨在研究5-羟色胺(5-HT)前体物对围产期母羊泌乳性能及血浆生化指标的影响。选择体况良好、体重(64.52±4.11) kg、处于同一围产期的30只巴美肉羊母羊,按体重随机分为3组,即对照组(灌注生理盐水)、5-羟基色胺酸(5-HTP)组(灌注5-HTP)和色氨酸(Trp)组(灌注Trp),每组10只。在母羊围产期产前第7天至产后当天(第0天),进行颈静脉灌注,5-HTP和Trp的灌注剂量均为0.178 mg/kg BW,浓度为0.1 mg/mL;对照组灌注同等剂量的生理盐水。试验期为产前第7天至产后第30天。结果表明:1) 5-HTP和Trp对母羊泌乳量及乳蛋白含量无显著影响(P 0. 05),但使母羊产后第3天乳脂和乳中非脂固体含量显著降低(P 0.05)。2) 5-HTP和Trp可以显著提高母羊产前第0天及产后第3、6、9天的血浆5-HT浓度(P0.05)。3) 5-HTP和Trp可以显著提高母羊产前第0天及产后第3、6、9天的血浆葡萄糖浓度(P0.05),显著降低母羊羊产前第0天及产后第3、9天的血浆非酯化脂肪酸(NEFA)浓度(P0.05),显著降低母羊羊产前第0天及产后第3、6天的血浆胰岛素(INS)浓度(P0.05)。由此可见,灌注5-HT前体物可以影响围产期母羊乳脂和乳中非脂固体含量,提高血浆葡萄糖浓度,降低血浆NEFA和INS浓度     

Winter-feeding systems for gestating sheep I. Effects on pre- and postpartum ewe performance and lamb progeny preweaning performance

Mature pregnant crossbred ewes (n = 90) were used in a randomized complete block design and assigned to 1 of 3 winter-feeding systems differing in primary feed source: haylage (HL), limit-fed corn (CN), or limit-fed dried distillers grains (DDGS). Effects of these winter-feeding strategies on ewe and lamb performance were determined. Diets were formulated to meet or exceed NRC (1985) nutrient requirements during gestation and were fed from about d 60 of gestation until parturition. All ewes were fed a common diet postpartum. Every 2 wk during gestation, BW and BCS were collected and diets were adjusted to maintain similar BW gain for ewes fed CN and DDGS vs. HL. At 80 and 122 d of gestation, jugular blood samples were collected at 0, 3, 6, and 9 h postfeeding to measure plasma glucose, insulin, NEFA, and blood urea nitrogen concentrations. At birth, 6 lambs per treatment were killed to measure body composition. At 28 ± 2 d postpartum, milk yield was measured. Lambs were weaned at 61 ± 4 d of age. During mid gestation (d 60 to 115), BW gain of ewes was similar among treatments; however, at d 115 of gestation ewes fed HL had a smaller (P = 0.04) BCS than ewes fed DDGS or CN. Plasma glucose concentrations were greater (P ≤ 0.004) in ewes fed CN than in those fed HL or DDGS just before feeding on d 80 and 122 of gestation, whereas ewes fed DDGS vs. CN or HL had greater (P ≤ 0.04) plasma insulin concentrations at 3 h postfeeding. At parturition, ewe BW was greatest for DDGS, least for HL, and intermediate for CN (P ≤ 0.003). Ewes fed CN and DDGS had greater BCS at parturition than those fed HL, but by weaning, ewes fed DDGS had greater BCS (P ≤ 0.05) than those fed CN or HL. Birth BW tended (P = 0.09) to be heavier for lambs from ewes fed CN and DDGS than from those fed HL prepartum, but there was no difference (P = 0.19) due to ewe gestation diet on lamb BW at weaning. At birth, lamb muscle, bone, organ, and fat measures were not affected (P > 0.13) by treatment. Ewe milk production and lamb preweaning ADG were also similar (P > 0.44) among treatments. Prepartum dam winter feed source did not have detrimental effects on pre- or postpartum ewe performance, but altered prepartum maternal nutrient supply during gestation, which affected birth weight but not preweaning growth or mortality.     

半胱胺对藏绵羊羔羊初生重及断奶重的影响

试验研究了半胱胺（Cs）对藏绵羊羔羊初生重及断奶重的影响。将20只妊娠（125±5）d的母羊随机分为2组（试验组和对照组）,在试验组日粮精料中添加300 mg/（kg·BW）的Cs,隔日添加1次,试验期90 d。于分娩后及时将初生羔羊称重,哺乳2个月强制断奶并称重。试验结果表明,试验组精料中添加Cs使藏绵羊羔羊初生重提高8.33%,2月龄断奶重提高13.73%。     

Plasma concentrations of key metabolites and insulin in late-pregnant ewes carrying 1 to 5 fetuses

Ewes bearing more than 1 fetus are more susceptible to pregnancy toxemia than those with a single fetus. Crossbreeding programs in Israel increased the occurrences of ewes bearing more than 2 fetuses; therefore, the aim was to assess the exacerbation in the metabolic status of ewes pregnant with several fetuses. Fifty ewes, genetically developed to achieve multiple-fetus pregnancies, were monitored, on average, from d 115 of pregnancy until lambing for plasma concentrations of several key metabolites and insulin. The numbers of fetuses were examined by ultrasonography at 35 d of pregnancy. Blood samples were collected weekly, and concentrations of glucose, β-hydroxybutyrate (BHBA), NEFA, triglycerides, cholesterol, total calcium, and insulin were determined. The average litter size was 2.75 (±1.1), and 1 (1F), 2 (2F), 3 (3F), and 4 or more (4F) fetuses were conceived, respectively, by 6 (12%), 17 (34%), 14 (28%), and 13 (26%) ewes. Total birth weights of lambs were 6.1, 9.5, 12.7, and 15.0 kg for 1F, 2F, 3F, and 4F, respectively (P < 0.001). Plasma glucose concentrations in 1F were greater than those in 3F and 4F (P < 0.05) and were similar among 2F, 3F, and 4F. Trends toward increasing plasma concentrations of BHBA and NEFA were observed as the number of fetuses increased and also as lambing approached. Plasma concentrations of BHBA and NEFA were, respectively, 3.7 (P < 0.002) and 2.1 (P < 0.001) times as great in 4F ewes as in 1F ewes. Trends toward decreased concentrations of triglycerides and cholesterol were observed as litter size increased. Insulin concentrations in blood decreased considerably as the numbers of fetuses increased and, on average, they were less by a factor of 5 in the 4F ewes than in the 1F ewes (P < 0.001). Moreover, insulin concentrations during the week before lambing were extremely low (e.g., 0.54 μIU/mL in the 4F ewes). Insulin concentrations were reduced in ewes bearing >3 fetuses, even 5 wk before lambing; this decline apparently began earlier than the last month of gestation. Therefore, it seems that insulin has a pivotal role in the etiology of pregnancy ketonemia in ewes carrying multiple fetuses. The present findings may suggest that the decline in insulin concentrations that apparently occurs in the earlier stages of pregnancy represents a homeorhetic control to spare glucose for the brains and fetoplacental units of the dams. The results clearly demonstrate the increased susceptibility to pregnancy toxemia of ewes carrying multiple fetuses. Appropriate nutritional strategies should be developed for ewes that conceive >3 fetuses, to meet the increased nutritional requirements of the fetoplacental unit.     

Impacts of maternal selenium and nutritional level on growth, adiposity, and glucose tolerance in female offspring in sheep

To examine effects of maternal nutrition and Se intake on adiposity and insulin sensitivity in female offspring, treatments were imposed during gestation on 82 pregnant primiparous Rambouillet ewe lambs (52.2 ± 0.8 kg) allotted randomly to 1 of 6 treatments in a 2 × 3 factorial arrangement. Factors were adequate (9.5 μg Se·kg BW(-1)·d(-1); ASe) or high (81.8 μg Se·kg BW(-1)·d(-1); HSe) levels of dietary Se (Se-enriched yeast) and maternal nutritional intake (100% of metabolizable energy [ME] requirement [MOD], 60% of MOD [LOW], and 140% of MOD [HIGH]). Selenium treatments were initiated at breeding and global nutritional treatments at day 50 of gestation. At parturition, lambs were removed from ewes before nursing and managed similarly. Glucose tolerance tests were performed at 107 and 148 d of age. Necropsies were performed at 180 d of age. Although there was no effect of Se on maternal body condition or weight during gestation, both maternal nutritional intake and selenium treatment influenced (P ≤ 0.04) offspring growth and response to a glucose tolerance test. Female lambs from HSe ewes were heavier (P = 0.04) at birth. There were nutritional intake and Se interactions (P ≤ 0.05) on the growth rate of the lambs and their insulin response to a glucose bolus at 2 different times during growth. By 180 d, ewe lambs from HSe ewes had more (P ≤ 0.07) internal fat stores than lambs from ASe ewes. It appears that both maternal nutritional level and Se intake can influence insulin sensitivity, and maternal Se intake alone can enhance fat deposition in female offspring.     

Uterine environment as a regulator of birth weight and body dimensions of newborn lambs

Pure-bred embryos were transferred within and reciprocally between large (Suffolk) and small (Cheviot) breeds of sheep to establish 4 treatment groups: SinS (Suffolk embryos in Suffolk dams), SinC (Suffolk embryos in Cheviot dams), CinS (Cheviot embryos in Suffolk dams), and CinC (Cheviot embryos in Cheviot dams). The recipient ewes carried single fetuses to term. The maternal plasma concentrations of ovine placental lactogen (oPL), progesterone, IGF-1, FFA, and glucose were measured on d 50, 90, 120, and 140 of pregnancy. Birth weight, body dimensions, and placental characteristics of lambs were recorded at birth. There was a recipient ewe breed × lamb breed × time interaction for the concentration of oPL (P = 0.03), but no such interaction was observed for progesterone (P = 0.42), IGF-1 (P = 0.57), glucose (P = 0.36), or FFA (P = 0.72). There were no differences in oPL (P = 0.28) and progesterone (P = 0.34) concentrations between SinC and SinS ewes. The concentrations of FFA on d 140 (P = 0.008), and those of glucose on d 50 (P = 0.02) and 120 (P = 0.01), were greater in SinC ewes than in SinS ewes. The ewes in CinS had less FFA concentration (P = 0.002) at all time points than CinC ewes. The concentrations of IGF-1 on d 90 were greater (P = 0.004) in CinS ewes than CinC ewes, but did not differ (P = 0.16) on d 50, 120, and 140. The concentrations of glucose on d 50 (P = 0.001), 90 (P = 0.03), and 140 (P = 0.03) were less in CinS ewes compared with CinC ewes. The birth weight of SinC lambs (5.04 ± 0.20 kg) was lighter (P = 0.001) than SinS lambs (5.94 ± 0.19 kg), and body dimensions of SinC lambs were smaller (P = 0.01) than SinS lambs. Neither birth weight nor the body dimensions of CinS lambs differed (P = 0.24) from CinC lambs. Cotyledon number was reduced (P = 0.04) in the CinS (57.5 ± 6.3) compared with the SinS group (74.2 ± 5.9), whereas mean cotyledon weight in CinS (2.42 ± 0.20 g) was greater (P = 0.02) than SinS (1.74 ± 0.21 g). It was concluded that the large genotype lambs were lighter and smaller when born to small genotype dams; however, the birth weight or body dimensions of small genotype lambs did not differ when born to large genotype dams. This study suggests that plasma oPL, progesterone, IGF-1, FFA, and glucose concentrations at different times throughout pregnancy reflect the regulatory effect of the uterine environment on the development of the fetus.     

Pharmacokinetics of ivermectin in pregnant and nonpregnant sheep

The plasma kinetic profile of ivermectin during the last trimester of pregnancy was studied in ewes after a single subcutaneous administration of 0.2 mg/kg body weight (BW). Sheep were randomly distributed into two groups. Ewes in group 1 (control, n=6) were left unmated, whereas in group 2 (pregnant, n=6) ewes were estrus-synchronized and mated with rams. Both groups were housed under similar conditions of management and feeding. At 120 days of pregnancy, both groups were given a subcutaneous injection of 0.2 mg/kg BW of ivermectin. Blood samples were taken by jugular puncture according to a fixed protocol between 1 h and 40 days post-treatment. After plasma extraction and derivatization, samples were analyzed by high performance liquid chromatography with fluorescence detection. A computerized pharmacokinetic analysis was performed, and the data were compared by means of the Student t-test. The results showed that plasma concentrations of ivermectin remained longer in the pregnant than in the control group. The mean values of pharmacokinetic parameters C(max), t(max), and area under the concentration-time curve (AUC) were similar for both groups of sheep. The mean residence time (MRT) values for the pregnant group (8.8+/-1.4 days) were higher (P<0.05) than those observed in the control group (5.3+/-1.9 days). It can be concluded that pregnancy increases the residence time of ivermectin in the plasma of pregnant sheep when it is administered subcutaneously.     

Maternal selenium supplementation and timing of nutrient restriction in pregnant sheep: Impacts on nutrient availability to the fetus

To determine the effects of maternal Se intake and plane of nutrition during mid or late gestation or both on AA concentrations and metabolite concentrations in the dam and fetus, pregnant ewe lambs (n = 64) were assigned to 1 of 8 treatments arranged in a 2 × 2 × 2 factorial array: Se level [initiated at breeding; adequate (ASe; 3.05 μg/kg of BW) or high (HSe; 70.4 μg/kg of BW)] and nutritional level [100% (control; CON) or 60% (restricted; RES) of NRC recommendations] fed at different times of gestation [d 50 to 90 (mid) or d 91 to 132 (late)]. A blood sample was obtained from each ewe and fetus on d 132 of gestation and used to measure circulating concentrations of glucose, NEFA, blood urea N, and AA. The late RES ewes and their fetuses had less (P ≤ 0.03) circulating glucose compared with late CON ewes and fetuses at d 132; however, no effect (P ≥ 0.14) of diet on the fetal:maternal glucose concentration ratio was observed. Late RES ewes had a smaller (P = 0.01) fetal:maternal NEFA ratio compared with late CON ewes. Ewes fed ASe had a greater (P = 0.01) fetal:maternal blood urea N ratio compared with HSe ewes. Fetal:maternal ratios of total circulating AA, total essential AA, and total nonessential AA were each affected (P ≤ 0.03) by the combination of Se treatment and late gestation nutritional level.     

Pregnancy stage and number of fetuses may influence maternal plasma leptin in ewes

Maternal plasma leptin is elevated in ewes during pregnancy. The authors studied whether there was any relation between maternal plasma leptin and insulin concentrations, the number of fetuses and the circulating and faecal levels of gestagens. At the end of the breeding season in January the ovarian activity of Prolific Merino ewes was induced/synchronised with gestagen + eCG treatment. Ewes were inseminated artificially (AI) by laparoscopy. Blood and faecal samples were collected before AI (day 0) and again 41, 81 and 101 days later. The plasma levels of leptin (pL), insulin and progesterone (pP4), and the faecal P4 metabolite (P4-met) content were determined. The day 0 level of pL was significantly higher in pregnant (n = 24) than in non-pregnant ewes (n = 32). By day 41 the pL of pregnant animals had doubled, it showed a further moderate increase on day 81, and decreased slightly thereafter. During pregnancy pP4 and faecal P4-met rose continuously and were positively correlated at all stages. The mean levels of pL and pP4 and the faecal content of P4-met were lower in ewes bearing single (n = 12) than in those with 2 (n = 6) or 3-5 fetuses (n = 6). Analysis of variance demonstrated significant differences according to the number of fetuses in the pL and pP4, but not in P4-met (p = 0.042, 0.044, and 0.051, respectively). Leptin showed positive correlation with insulin before the AI but not during pregnancy. On days 41 and 81 pL showed a slight positive correlation with P4 and P4-met, which decreased slightly by day 101. This study shows that although leptinaemia is affected by the number of fetuses and the level of P4, pregnancy stage is a more important regulator than these additional factors.     

钼对镉胁迫下山羊肝线粒体自由基代谢及肝Cyt-c基因mRNA表达的影响

选用27头健康波尔山羊随机分成3组,每组9头,选用钼酸铵[（NH4）6Mo7O24·4H2O]、氯化镉（CdCl2）作为试验钼源、镉源。对照组（试验Ⅰ组）口服相应剂量去离子水,试验Ⅱ、Ⅲ组灌服1mg Cd·kg^-1·BW,同时分别灌服15、45mg Mo·kg^-1·BW。试验50d,于0、25、50d每组剖杀3头山羊取肝组织样进行相关试验,观察钼镉对山羊肝线粒体自由基代谢及Cyt-c基因表达的影响。结果显示,与对照组比较,试验Ⅱ、Ⅲ组T-AOC、SOD活性下降（P〈0.05）,MDA、NO、NOS活性或含量及Cyt-c基因mRNA表达量上升（P〈0.05）,且随着试验时间的延长,T-AOC、SOD呈下降趋势（P〈0.05）;MDA、NO、NOS活性或含量及Cyt-c基因mRNA表达量呈上升趋势,试验钼镉组比较：当镉剂量一定时,试验钼镉组随着灌服钼剂量的升高,T-AOC活性呈下降趋势,MDA、NO、NOS活性或含量及Cyt-c基因mRNA表达量呈上升趋势。结果表明,钼可导致镉胁迫下山羊肝线粒体自由代谢紊乱,造成线粒体损伤同时诱导细胞凋亡相关基因Cyt-c表达上升,钼与镉呈协同效应。