不同氮能比饲粮对妊娠环江香猪羊水和尿囊液生化参数的影响

本试验旨在研究不同氮能比饲粮对妊娠环江香猪羊水和尿囊液生化参数的影响。选用首次妊娠环江香猪48头,随机分为2组,每组8个重复(栏),每个重复3头。配种后2组母猪分别饲喂高氮能比饲粮(消化能为14.73 MJ/kg,粗蛋白质含量为13.11%,氮能比为0.89)和低氮能比饲粮(消化能为12.24 MJ/kg,粗蛋白质含量为9.77%,氮能比为0.80),于妊娠第45、75和110天每栏取1头母猪屠宰,收集每窝中最大体重、中间体重和最小体重胎猪对应的羊水和尿囊液,测定生化参数。结果表明:在相同妊娠时间和相同标准体重条件下,与饲喂低氮能比饲粮相比,饲喂高氮能比饲粮可显著增加尿囊液中妊娠75 d最小体重胎猪碱性磷酸酶活性(P0.05),显著降低妊娠75 d中间、最小体重胎猪和妊娠110 d最小体重胎猪谷草转氨酶活性,妊娠45、75 d最大体重胎猪尿酸含量,妊娠45 d中间、最小体重胎猪和妊娠75 d最大体重胎猪肌酸激酶活性(P0.05)。与最小体重胎猪相比,高氮能比饲粮组妊娠45和75 d以及低氮能比饲粮组妊娠45和110 d时最大体重胎猪羊水中白蛋白含量显著增加(P0.05)。随着妊娠时间的延长,2个饲粮组胎猪羊水中尿素和尿酸含量以及尿囊液中尿酸含量逐渐增加。由上可见,高氮能比饲粮可通过调节羊水和尿囊液生化参数促进胎猪的生长发育;与中间和最小体重胎猪相比,最大体重胎猪对蛋白质的利用效率更高。     

高、低营养水平饲粮对妊娠环江香猪繁殖性能、体成分和血浆生化参数的影响

本试验旨在研究高、低营养水平饲粮对妊娠母猪繁殖性能和体成分的影响,并探讨其生化机制。选用首次妊娠的环江香猪48头,根据体重随机分为2组,每组8个重复(栏),每重复3头。配种后分别饲喂NRC饲粮[消化能(DE)为14.73 MJ/kg,粗蛋白质(CP)含量为13.11%]和地方猪饲粮(DE为12.24 M J/kg,CP含量为9.77%)。分别于配种后45、75和110 d称取母猪体重,每栏选取1头母猪,前腔静脉采血用于生化参数分析,放血处死后解剖,记录胎猪头数,称取胎猪个体重,并测定母体成分。结果表明:与地方猪饲粮组相比,NRC饲粮组母猪的繁殖性能和体成分指标差异均不显著(P0.05),妊娠45和75 d时血浆谷丙转氨酶以及妊娠75 d时谷草转氨酶活性均显著降低(P0.05),妊娠45 d时低密度脂蛋白-胆固醇浓度,妊娠75 d时碱性磷酸酶活性、高密度脂蛋白-胆固醇和总胆固醇浓度以及整个妊娠期甘油三酯浓度均显著升高(P0.05);在不同妊娠期,2种饲粮对各测定指标的影响有一定差异。由此可见,2种饲粮对环江香猪的繁殖性能和体成分均无显著影响;NRC饲粮在一定程度上改善了机体代谢,促进了生长发育,但同时增加了脂肪沉积。     

妊娠母羊饲粮添加叶酸对不同出生类型新生羔羊脐带血管生成相关基因表达的影响

试验旨在研究妊娠母羊饲粮添加叶酸对不同出生类型新生羔羊脐带血管生成相关基因表达的影响。选用体重相近、年龄一致的经产湖羊母羊120只,人工授精后随机分为3组,分别单栏饲喂补充0、16和32 mg/kg DM叶酸的全混合日粮。母羊分娩时,每组随机采集出生类型为双羔和三羔的胎盘与脐带样品各3个,共18个样品用于测定胎盘相关指标,胎儿脐带样品利用实时荧光定量PCR法检测血管生成相关基因——血管内皮生长因子A(VEGFA)、转换生长因子-β3(TGF-β3)、血管生成素-1(ANGPT-1)、血管内皮生长因子受体-1(FLT-1)和血管内皮生长因子受体-2(KDR)基因的相对表达水平。结果表明:妊娠母羊饲粮添加叶酸对胎盘重、子叶数、胎盘效率无显著影响(P>0.05),对新生羔羊脐带TGF-β3、ANGPT-1、FLT-1、KDR基因的相对表达水平无显著影响(P>0.05),但能显著提高VEGFA基因的相对表达水平(P<0.05)。而出生类型对胎盘重、子叶数、胎盘效率和新生羔羊脐带VEGFA、TGF-β3、FLT-1、KDR基因的相对表达水平无显著影响(P>0.05),但是三羔脐带ANGPT-1基因的相对表达水平显著高于双羔(P<0.05)。由此可见,妊娠母羊饲粮添加叶酸对胎盘发育没有显著影响,但是显著提高了新生羔羊脐带VEGFA基因的相对表达水平,有利于新生羔羊脐带血管生成。同时,新生羔羊三羔脐带ANGPT-1基因的相对表达水平显著高于双羔,有利于多羔脐带血管生成。     

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。     

Effects of Dietary Arginine and Alanine on Meat Quality, Amino Acid Composition and Antioxidant Function in Huanjiang Mini-Pigs

本试验旨在研究饲粮精氨酸与丙氨酸对环江香猪肉质、氨基酸组成及抗氧化功能的影响,选用体重为28～33 kg的环江香猪16头(公母各占1/2),按体重相近原则随机分为2组,每组4个重复,每个重复2头猪.丙氨酸组在基础饲粮中外源添加1.71％的L-丙氨酸(等氮对照),精氨酸组在基础饲粮中外源添加0.83％的L-精氨酸和0.88％的米糠.试验期为45 d.结果表明:与丙氨酸组相比,精氨酸组瘦肉率显著提高(P＜0.05),脂肪率和背最长肌中粗脂肪含量显著降低(P＜0.05);肝脏丝氨酸、缬氨酸、亮氨酸和异亮氨酸含量显著提高(P＜0.05);血浆过氧化氢酶活性显著提高(P＜0.05),丙二醛含量显著降低(P＜0.05).上述结果提示,饲粮中适宜水平的精氨酸可提高环江香猪瘦肉率,降低脂肪率,增强机体抗氧化功能,从而改善部分肉品质指标.     

N-氨甲酰谷氨酸对环江香猪生长性能、营养物质消化率及血浆游离氨基酸含量的影响

为了探讨N-氨甲酰谷氨酸(N-carbamylglutamate,NCG)对环江香猪生长性能、营养物质消化率及血浆游离氨基酸含量的影响,试验选用平均体重为(12.6±1.7) kg的环江香猪10头,随机分为2组,每组5个重复,每个重复l头猪,单笼饲养,分别饲喂基础饲粮和添加0.1％ NCG的试验饲粮,试验期为10 d....     

外源精胺对断奶仔猪小肠黏膜成纤维细胞因子-2蛋白质表达量及小肠发育的影响

本试验旨在研究外源精胺对断奶仔猪小肠黏膜成纤维细胞因子-2( FGF2)蛋白质表达量及小肠发育的影响。将9窝胎次和初生体重相近的7日龄“杜×长×大”哺乳仔猪随机分配到0、12和15 mg/kg外源精胺组,每组3窝。仔猪从7日龄起补饲相应的饲粮,21日龄断奶后继续补饲断奶前饲粮至28日龄结束。从每窝选2头接近平均体重的仔猪屠宰,采集小肠及黏膜样品,测定FGF2蛋白质表达量和小肠的发育状况。结果表明：1)12 mg/kg外源精胺组仔猪小肠黏膜FGF2蛋白质表达量分别高于0和15 mg/kg外源精胺组,但3个外源精胺组仔猪小肠黏膜FGF2蛋白质表达量之间无显著差异(P>0.05)。2)12和15 mg/kg外源精胺组仔猪小肠绒毛高度和宽度分别极显著大于0 mg/kg外源精胺组( P<0.01),而12 mg/kg外源精胺组仔猪十二指肠和空肠黏膜绒毛高度与隐窝深度比值( V/C )分别极显著高于0 mg/kg外源精胺组( P<0.01)。3)28日龄仔猪小肠黏膜蔗糖酶和麦芽糖酶活性随外源精胺添加量的增加而升高。由此可见,给7~28日龄仔猪连续补饲外源精胺能提高28日龄仔猪小肠黏膜FGF2蛋白质表达量、V/C和二糖酶活性。     

高原牦牛睾丸组织VEGF及其受体的增龄性分布特点

探索VEGF及其受体(VEGFR2)在不同年龄牦牛睾丸的分布特点。应用免疫组织化学SP法检测VEGF及其受体(VEGFR2)分布特征并通过IPP图像分析软件进行定量统计。免疫组织化学显示,不同年龄段牦牛睾丸中,VEGF表达于各级生精细胞以及Sertoli细胞和Leydig细胞,强表达于长形精子,小血管内皮细胞见强阳性表达,肌样细胞未见表达;其受体VEGFR2表达于各级生精细胞及Sertoli细胞,且Leydig细胞内强表达,小血管弱表达;牦牛幼龄期至性成熟期,睾丸中VEGF表达量呈明显上升趋势(P0.05),性成熟期达到最高水平,进入老龄期后表达量明显下降(P0.05);其受体VEGFR2表达量性成熟前期最高,进入老龄期下降不明显。因此,牦牛睾丸中VEGF及其受体随年龄增加存在差异性表达,幼龄期随增加明显,性成熟期趋于稳定,老龄后下降显著,提示其可能参与调节牦牛生后睾丸发育的各个阶段,且与高原牦牛睾丸血管发育,生精及其低氧适应具有一定的关系。     

饲粮蛋白质水平对妊娠期云南半细毛羊氮平衡和养分排放的影响

本试验旨在研究饲粮蛋白质水平对妊娠期云南半细毛羊氮平衡和氮、磷、钙排放的影响.选取50只体况良好、体重[(46.52±4.58)kg]相近、年龄一致、配种日期相同的经产2胎妊娠期云南半细毛羊,随机分为5组,每组10个重复,每个重复1只羊.5组试验羊在妊娠前期和中期饲喂蛋白质水平分别为6.65％(Ⅰ组)、9.02％(Ⅱ组...     

精准营养下低排饲粮对生长猪生长性能、骨骼特性及氮平衡的影响

试验旨在研究基于理想氨基酸模型,精准营养下低排饲粮对生长猪生长性能、骨骼特性及氮平衡的影响,为指导低排饲粮的推广应用提供依据。试验选取体重相近、健康的约20 kg杜×长×大三元杂交生长猪72头,随机分为2组,即对照组和试验组,每组6个重复,每个重复6头,分别饲喂基础饲粮和低排饲粮,试验期36 d。结果表明:相比对照组,低排饲粮对生长猪的生长性能无显著影响(P>0.05);低排饲粮对生长猪的骨骼发育无显著影响(P>0.05);低排饲料显著降低总氮摄入量、粪氮、尿氮和总氮排放量(P<0.05),显著提高氮沉积率和氮消化率(P<0.05)。在氨基酸平衡条件下,低排饲料对生长猪的生长性能和骨骼发育无显著影响,但能够降低氮排放,提高蛋白质的利用率。     

Influence of Carnichrome on the energy balance of gestating sows

Twelve multiparous sows with an average initial weight of 182 kg were used in a randomized complete block design to determine the effects of feeding Carnichrome (50 mg of carnitine and 200 microg of chromium picolinate per kilogram of feed, as fed) on energy and nitrogen utilization in early, mid-, and late gestation. All sows were fed a diet with or without Carnichrome for the preceding 28-d lactation, the weaning-to-estrus period, and for the duration of gestation. Daily feeding allowances over pregnancy were based on calculated energy and nutrient requirements to achieve a target sow maternal weight gain of 20 kg and remained constant throughout gestation. Heat production (HP) and its partitioning (activity, thermic effect of feeding short term [TEFst], basal) were determined in early (wk 5 or 6), mid- (wk 9 or 10), and late (wk 14 or 15) pregnancy using indirect calorimetry. Net maternal weight gain and total number of fetuses averaged 21.6 kg and 16.4, respectively. Organic matter and energy digestibility for the Carnichrome diet was greater (P < 0.05), which resulted in greater DE and ME contents (0.6%, P < 0.05) compared with the control diet. The digestibility coefficient of energy in the current experiment for a typical corn and soybean meal diet (92%) was greater than that predicted from DE values of corn and soybean meal in feeding tables (88%). Carnichrome had no effect on total HP, energy retained as protein or lipid, and maternal energy retention in early, mid-, or late gestation. Heat production in late gestation increased linearly (4.0 kJ/[kg BW0.75 x d]) for each additional day from d 90 to 110, despite the reduction of ME intake per unit of BW0.75. Metabolizable energy requirement for maintenance was 405 kJ/(kg BW0.75 x d). On average, activity HP was 116 kJ/(kg BW0.75 x d), which was equivalent to 20% of ME intake; however, this value ranged from 11 to 37% between sows, which corresponds to duration of standing ranging from 210 to 490 min/d. Energy cost of standing activity averaged 0.30 kJ/(kg BW0.75 x min). In conclusion, Carnichrome had no effect on the components of heat production and maternal weight gain during gestation, although it improved energy and organic matter digestibility of the diet.     

Blood flow and steroid and nutrient uptake of the gravid uterus and fetus of sows

Uterine and umbilical blood samples and blood flow (BF) measurements were obtained from one uterine horn and a single fetus of sows at d 70, 90 and 110 of gestation. Concentrations of O2 in blood and of estrogen (E), progesterone (P), glucose, alpha-amino nitrogen (N) and urea N in plasma were determined. Fetal weights were .267 +/- .018, .633 +/- .019 and 1.208 +/- .073 kg on d 70, 90 and 110, respectively. Uterine and umbilical BF remained constant with day of gestation, averaging 1.51 +/- .06 and .31 +/- .02 liters/min. Uptake of P by a uterine horn and fetus remained constant, but secretion of E by a uterine horn and uptake of E by a fetus increased (P less than .05) with stage of gestation. Uterine and fetal uptake of O2, glucose and alpha-amino N did not change and uptake of O2, glucose and alpha-amino N per kg fetus decreased (P less than .01) as gestation advanced. Secretion of urea N from the uterus was observed, with a concentration gradient from the fetal to the uterine circulations. Uterine and fetal respiratory quotients for glucose were .79 and .38, respectively. Thus, although glucose potentially served as a major energy source, a large portion of the energy requirements of the fetal pig were met by catabolism of other substrates. The decrease in umbilical BF and uptake of nutrients per kg fetus with day of gestation suggested that porcine fetal metabolism declined as pregnancy advanced.     

Expression of the Vascular Endothelial Growth Factor (VEGF‐A) and its Receptors in the Umbilical Cord in the Course of Pregnancy in the Pig

The umbilical cord (UC) and the placenta are important organs through which respiratory gases, nutrients, wastes and biologically active substances are exchanged between the maternal and the foetal system. A rapid placental vascularization observed in the second half of pig pregnancy is positively correlated with the mRNA expression of the vascular endothelial growth factor (VEGF). Based on these findings, we hypothesized that VEGF may have a stimulatory effect in the dynamically growing UC. To further understand the role of the VEGF–VEGFR system during UC development, mRNA and protein expression as well as the cellular localization of VEGF‐A, VEGFR‐1 and VEGFR‐2 in UC were examined on days 40, 60, 75 and 90 of pregnancy and after physiological delivery in the pig (day 114 of pregnancy). Real Time RT‐PCR analysis showed an increase in the mRNA levels of VEGF120 and VEGF164 from day 90 of pregnancy. VEGFR‐1 mRNA expression was significantly increased on day 75 of pregnancy. No significant changes in VEGFR‐2 mRNA expression were detected. In turn, western blot analysis revealed an increase in VEGF‐A protein expression on day 40, compared to the later days of pregnancy. A rapid increase in the VEGFR‐1 protein level was noted on day 75 and 90 of gestation. No significant changes in VEGFR‐2 protein expression were detected on any of the analysed days of pregnancy. Immunohistochemical staining enabled detection of VEGF–VEGFR system, in endothelial and tunica media cells of the umbilical vessels and in allantoic duct and amniotic epithelium on all analysed days of pregnancy. Positive reactions for VEGF‐A and VEGFR‐1, but not VEGFR‐2, were also observed in myofibroblasts. In conclusion, this data shows that members of the VEGF–VEGFR system are temporally and spatially well localized for playing key roles during umbilical cord formation and its intensive growth observed after day 75 of pregnancy.     

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.     

Histochemical studies of muscle development in decapitated and hypophysectomized pig fetuses: blood vessel development

In Exp. 1, fetuses were decapitated in utero on d 45 of gestation and examined at 110 d of gestation; in Exp. 2, fetuses were hypophysectomized (hypox) in utero with a cauterizing needle at d 70 of gestation and examined at 110 d of gestation. Semitendinosus muscles were sampled and transverse cryostat sections were cut from the medial portion of the muscle. Quantitative analysis of lectin-stained sections showed that capillary:fiber ratios (C/F) were lower (P less than .01) for sections from decapitated and hypox fetuses than for sections from control fetuses. The superficial and deep aspects of muscle sections from control fetuses had markedly different C/F ratios (deep region, 24.1 +/- 2; superficial region, 11.2 +/- .5). Fetal decapitation and hypophysectomy abolished differences in C/F ratios between deep and superficial regions of muscle sections (hypox fetuses; deep region, 6.9 +/- 1; superficial region, 6.4 +/- .6). Capillaries in sections from control fetuses were reactive for several enzymes, whereas capillaries in sections from experimental fetuses (decapitated and hypox) were not reactive for these enzymes. The number of small arterioles was reduced in sections from experimental fetuses (decapitated and hypox) compared with sections from control fetuses. These studies demonstrate that lowering the levels of pituitary hormones in the fetus retards the development of blood vessels in muscle tissue both quantitatively and qualitatively.     

饲粮添加脯氨酸对妊娠环江香猪繁殖性能和血浆生化参数的影响

本试验旨在研究脯氨酸代谢对妊娠环江香猪繁殖性能的影响,并探讨其可能的生理生化机制。选取48头后备环江母猪,配种15 d后随机分成3组,每组8个重复,每个重复2头猪。各组分别饲喂添加0.77%L-丙氨酸(丙氨酸组)、1%L-脯氨酸(脯氨酸组)、0.77%L-丙氨酸+0.016 7%二氟甲基鸟氨酸(DFMO)(DFMO组)的试验饲粮。分别于配种第45和70天,每重复随机取1头母猪,放血处死,收集血液,用于生化参数分析;解剖母猪,记录黄体数、胎儿数和胎儿重。结果表明:妊娠第70天时,脯氨酸组窝重显著高于丙氨酸组(P0.05);妊娠第45天时,脯氨酸组血浆谷丙转氨酶活性以及白蛋白浓度均显著低于丙氨酸组(P0.05)。妊娠第70天与第45天相比,脯氨酸组血浆总胆固醇浓度、DFMO组血浆高密度脂蛋白和白蛋白浓度均显著降低(P0.05)。其余指标各组间均无显著差异(P0.05)。由此可见,饲粮添加脯氨酸可能通过改善机体氮代谢和脂肪代谢而促进妊娠环江香猪胎儿的生长发育。     

饲粮能氨水平对不同品种猪肉质性状及相关基因表达的影响

本试验旨在研究饲粮能氮水平对不同品种猪肉质性状以及肌纤维类型和细胞因子相关基因表达的影响.选取巴马香猪和长白猪共96头(48头/品种),随机分为4组(每组24头猪),分别为长白猪饲喂NRC饲粮组、长白猪饲喂我国地方猪标准(GB)饲粮组、巴马香猪饲喂NRC饲粮组、巴马香猪饲喂GB饲粮组.试验从5周龄开始,至出栏时结束.分别于保育期、生长期和肥育期末,每组选择8头体况相近猪只屠宰,采集肌肉样品分析.结果表明:生长阶段显著影响了试验猪背最长肌熟肉率和肌球蛋白重链(MyHC)Ⅱx、MyHCⅡ易及白细胞介素-15(IL-15)mRNA表达水平(P<0.05),且随生长阶段呈增加趋势;与长白猪相比,巴马香猪的背最长肌熟肉率、MyHC Ⅰ mRNA表达水平显著升高(P<0.05),而滴水损失显著降低(P<0.05);与NRC饲粮相比,GB饲粮显著提高了生长期长白猪和巴马香猪的pH45 min(P<0.05),显著上调了保育期和肥育期猪背最长肌MyHC Ⅰ mRNA表达水平(P<0.05);与GB饲粮相比,NRC饲粮显著上调了生长期猪背最长肌MyHC Ⅰ mRNA表达水平(P<0.05).由此可见,品种和生长阶段均可显著影响肉质性状及相关基因的表达,饲粮能氮水平则主要通过与生长阶段产生互作效应影响肉质性状及肌纤维类型相关基因的表达.