【作者】 张浩；

【导师】 王锋；

【作者基本信息】 南京农业大学 ， 动物营养与饲料科学， 2016， 博士

【摘要】 本论文主要围绕肉羊饲养管理中相关营养需要量的确定和宫内发育迟缓(IUGR)的预防两大问题展开研究。首先,本研究制定了杜湖F1代育肥期常量元素和微量元素的营养需要量以及湖羊妊娠期能量和蛋白质的维持需要量;其次,探讨了过瘤胃精氨酸(RP-Arg)和氮-氨甲酰谷氨酸(NCG)对营养限饲妊娠湖羊胎儿、胎盘发育的影响,旨在为湖羊及其杂交F1代的健康养殖,以及胎羊IUGR现象的预防和治疗提供理论依据。试验共分为五大部分,分别为:试验一、杜湖杂交羊-F1代育肥期常量元素营养需要量的研究本研究采取比较屠宰法测定杜湖杂交羊F1代育肥期常量元素(Ca、P、K、Na和Mg)的净维持和生长需要量。试验分为两期:育肥前期(20-35kg公母)和育肥后期( 35-50kg公母)。每期每个性别选择35只羔羊(育肥前期和后期初体重分别为19.2±0.36kg和33.45±0.64kg)用于本试验。每个性别随机选取7只羊,在育肥前期大约20kg或者育肥后期35kg时进行屠宰以测定常量元素体成分的初始值。每个性别另外7只羊随机选择,且饲喂全混合颗粒日粮,自由采食,体重在大约28kg (育肥前期)或者42kg (育肥后期)时进行屠宰。每个性别剩余的21只羔羊随机分为3个组,分别为自由采食组(AL)、70%AL和40%AL,每组7只羊。当自由采食组体重大约为35kg(育肥前期)或者50kg (育肥后期)时,每个性别的这三组将被屠宰。屠宰后,测定空腹体(头+足、皮、内脏+血液和胴体)常量元素含量。本研究结果显示,育肥前期公羔和母羔的常量元素净维持需要量分别为24.01和22.21 mgCa、11.70和11.65 mg P、3.20和3.41mgNa、6.60和6.92mg K、1.20和 1.23mgMg/kgEBW(空腹体重)。育肥前期公羔的净生长需要量分别为 11.55-11.41 gCa、5.82-5.77gP、1.47-1.69gK、0.42-0.44 g Mg和0.98-0.88 g Na /kg EBWG(空腹体增重);母羔的净生长需要量分别为11.93-11.68 gCa、6.12-5.71 gP、1.58-1.63 gK、0.41-0.36 g Mg和 1.34- 1.24 gNa/kg EBWG。育肥后期公羔和母羔的常量元素净维持需要量分别为27.03和22.20 mg Ca、12.53和 13.50mgP、3.72和3.80mgNa、7.10和7.91mg K、1.42和1.10mgMg/kgEBW。育肥后期公羔的净生长需要量分别为11.12-11.43 gCa、5.82-5.93 gP、1.71-1.91 gK、0.46-0.48 g Mg 和 0.96-0.92 gNa/kg EBWG;母羔的净生长需要量分别为 11.79-12.06 gCa、6.04-6.16gP、1.66-1.74gK、0.40-0.42gMg和0.98-0.95 gNa/kgEBWG。杜湖F1代育肥期净常量元素需要量的确定将有助于此生长阶段合理日粮的配制,有利于羔羊生产性能的提高。试验二、杜湖杂交F,代羊育肥期微量元素营养需要量的研究本研究采取比较屠宰法测定杜湖杂交F1代育肥期微量元素(Fe、Mn、Cu和Zn)的净维持和生长需要量。试验分为两期,具体分组和材料方法参照试验一。屠宰后,测定空腹体(头+足、皮、内脏+血液和胴体)微量元素含量。本研究结果显示,育肥前期公羔和母羔的微量元素净维持需要量分别为356.1和164.1 μgFe、4.3和3.4 μgMn、42.0和29.8μgCu、83.5和102.0μgZn/kgEBW。育肥前期公羔Fe、Mn、Cu的净生长需要量逐渐降低,而Zn逐渐升高,分别为65.67-57.27 mg Fe、0.35-0.25 mg Mn、3.45-2.82 mg Cu和26.36-26.65 mg Zn/kgEBWG。母羔Fe、Mn、Cu、Zn的净生长需要量逐渐降低,分别为 30.66-22.14 Fe、0.43-0.32 Mn、2.86-2.18 Cu和27.71-25.83 Znmg/kgEBWG。育肥后期公羔和母羔的微量元素净维持需要量分别为429.3和310.4 μg Fe、5.1和4.4μg Mn、48.8和35.7μgCu、94.6和110.3μgZn/kgEBW。育肥后期公羔Fe和Cu的净生长需要量逐渐降低,而Mn和Zn逐渐升高,分别为70.41-68.40 mg Fe、4.31-4.15 mg Cu、0.86-0.93 Mn和33.46-35.20 mg Zn/ kg EBWG。除Zn外,母羔Fe、Mn和Cu的净生长需要量逐渐降低,分别为41.02-37.05 Fe、0.52-0.49 Mn、3.39-3.10 Cu和34.21-35.80 Zn mg/kgEBWG。本研究表明,杜湖杂交F1代羊育肥期净微量元素需要量可能与其纯种或其他品种有所不同,需进一步补充完善。试验三、湖羊妊娠期能量和蛋白质维持需要量的研究本研究利用碳-氮(C-N )平衡法,同时结合消化代谢和气体代谢试验,测定妊娠时间点和采食水平对能量代谢、C-N平衡和甲烷(CH4)产气量的影响,并制定妊娠期湖羊能量和蛋白质维持需要量。选取怀有双羔的妊娠湖羊21只,随机分配3个试验组(AL; 70% AL; 50% AL),每组7只羊。在湖羊妊娠期40、100和130 d,分别进行消化代谢和气体代谢试验。结果表明,从40到100 d,干物质采食量(DMI)显著升高(P<0.05),到130d时显著降低(P<0.05)。在每个妊娠时间点,C和N的表观消化率都随着采食水平的降低而显著升高(P< 0.05); C表观消化率随着妊娠时间点的增加而显著升高(P< 0.05);在妊娠100dN表观消化率显著高于40和130d(P<0.05)。在每个妊娠时间点,CH4产气量(L/kgDMI; L/kgNDFI)皆随着采食水平的升高而显著降低(P< 0.05);并从妊娠40到100 d显著升高(P< 0.05),但在妊娠130 d显著降低(P< 0.05)。在妊娠期40、100和130 d的维持净能(NEm)分别为295.80、310.09和323.59 kJ/kgW0’75;代谢能维持利用效率(km)分别为0.664、0.644和0.620;净蛋白质维持需要量(NPm)分别为1.99、2.35和2.99 g/kgW0.75。湖羊妊娠期能量和蛋白质维持需要量的制定,将有助于此阶段合理日粮的配制,进而提高生产效率。试验四、RP-Arg和NCG对限饲湖羊胎儿发育和氨基酸代谢的影响IUGR现象是一个缺少有效治疗的严重健康问题。本研究建立妊娠期湖羊IUGR模型,通过日粮中补充RP-Arg和NCG,并进一步验证其对胎儿发育起促进作用的假设。从妊娠35 d开始,妊娠母羊分为四组,每组8只。四组分别为:100%NRC( n=8 )、50%NRC(n=8)、50%NRC基础上添加20g/d RP-Arg (n=8 )和50%NRC基础上添加5 g/d NCG(n=8)。直至110 d时,妊娠母体、胎儿、胎盘组织以及胎儿液采集,并称重。妊娠母羊体重在50%NRC组显著(P<0.05)低于100%NRC组,且RP-Arg和NCG的添加并未显著提高妊娠母羊体重(P> 0.05)。与50% NRC组相比,RP-Arg和NCG补饲组显著(P<0.05)提高了大多数胎儿器官的重量;RP-Arg和NCG补饲组显著(P<0.05)降低了母体血液中β-羟基丁酸、甘油三脂(TG)和氨气(NH3)的浓度,而对乳酸和生长激素(GH)浓度无显著影响(P > 0.05); RP-Arg和NCG补饲组显著(P< 0.05)提高了母体和胎儿血液中氨基酸浓度(尤其精氨酸家族氨基酸和支链氨基酸)以及羊水和尿囊液中多胺浓度。本试验研究结果表明,RP-Arg和NCG对限饲妊娠母羊补饲在某种程度上通过提高孕体中氨基酸利用的有效性来预防IUGR发生,并为其应用于人类和肉羊生产中IUGR的治疗提供理论依据。试验五、RP-Arg和NCG对限饲妊娠湖羊、胎儿抗氧化性能和胎盘发育的影响本研究目的是在营养限饲妊娠湖羊日粮中添加RP-Arg和NCG将如何影响:(1)母体内分泌状态;(2)母体、胎儿和胎盘抗氧化性能;(3)胎盘发育。从妊娠35至110d,妊娠母羊分为四组,每组8只。四组分别为:100%NRC(n=8)、50%NRC(n=8)、50% NRC基础上添加20g/d RP-Arg (n=8 )和50% NRC基础上添加5 g/d NCG ( n=8 )。研究结果表明,与限饲组相比,RP-Arg和NCG,母体、胎儿血液及胎盘的总抗氧化活性(T-AOC)和超氧化物歧化酶活性(SOD)显著升高(P<0.05),而谷胱甘肽还原酶活性(GSH-Px)和丙二醛活性(MDA)显著降低(P<0.05)。与100% NRC组相比,50% NRC组中胎盘内皮生长因子(VEGF)及其受体(FLT1) mRNA表达量显著升高(P<0.05),而添加RP-Arg和NCG后对其mRNA表达量并无影响。与限饲组相比,添加RP-Arg和NCG显著降低了孕酮、皮质醇和雌二醇的浓度(P< 0.05),显著提高了瘦素、类胰岛素生长因子、三碘甲状腺氨酸(T3)和甲状腺素(T4)的浓度(P<0.05),而对T4/T3无显著影响(P> 0.05)。结果表明,营养限饲妊娠湖羊日粮添加RP-Arg和NCG能够影响母体内分泌状态,提高母体、胎儿和胎盘抗氧化能力,促进胎儿和胎盘的发育。更多还原

【Abstract】 A comparative slaughter trial was conducted to estimate the net macromineral and trace elementrequirements for maintenance and growth of Dorper x Hu lambs; the digestion trial, respirometry trial, and carbon and nitrogen balance trial was conducted to determine energy and protein requirements for maintenance and the effect of feed intake level on energy metabolism, carbon-nitrogen balance, and methane emission of Hu sheep during pregnancy; an ovine intrauterine growth restriction (IUGR) model was established to test the hypothesis that dietary N-carbamylglutamate (NCG) and rumen-protected L-arginine(RP-Arg) supplementation are effective in ameliorating fetal growth restriction in undernourished ewes, and to determine how dietary NCG and RP-Arg supplementation in nutrient restricted pregnant Hu sheep would affect 1) maternal endocrine status; 2) maternal,fetal, and placental anti-oxidation capability 3) placental development. These results for the nutritional requirements may help to formulate more balanced diets for Dorper x Hu lambs in the growing period and Hu ewes during pregnancy. These results also indicate that dietary NCG and RP-Arg supplementation to underfed ewes could influence maternal endocrine status, improve the maternal-fetal-placental anti-oxidation capability and promote fetal and placental development during early to late gestation.1. The net macro mineral requirements for maintenance and growth of Dorper x Hu lambsA comparative slaughter trial was conducted to estimate the net macro mineral requirements for maintenance and growth of Dorper x Hu male and female lambs.Thirty-five lambs from each sex with an initial body weight (BW) of 19.2±0.36 kg (in the early growing period) or 33.45±0.64 kg (in the late growing period), respectively,were used. Seven lambs from each sex were randomly chosen and slaughtered at 20kg (in the early growing period) or 35kg (in the late growing period) BW as the baseline group for measuring initial body composition. Another seven lambs from each sex were also randomly chosen and offered a pelleted mixed diet for ad libitum intake and slaughtered at 28 kg (in the early growing period) or 42 kg (in the late growing period) BW. For each sex,the remaining lambs (n = 21) were allocated randomly on d 0 to 3 treatment intake levels(treatments were ad libitum or restricted to 70 or 40% of the ad libitum intake) within 7 slaughter groups. A slaughter group contained 1 lamb from each treatment, and lambs were slaughtered when the ad libitum treatment lamb reached approximately 35 kg (in the early growing period) or 50 kg (in the late growing period) BW. Empty bodies of the lambs (head+ feet, hide, internal organs + blood, and carcass) were weighed, ground, mixed, and subsampled for chemical analyses. In the early growing period, the net macromineral requirements for maintenance were 24.01 mg Ca, 11.70 mg P, 3.20 mg Na, 6.60 mg K, and 1.20 mg Mg/kg of empty BW (EBW) for males. The net macromineral requirements for maintenance were 22.21 mg Ca, 11.65 mg P, 3.41 mg Na, 6.92 mg K, and 1.23 mg Mg/kg EBW for females. The daily net requirements for growth ranged from 11.55 to 11.41 g Ca,5.82 to 5.77 g P, 1.47 to 1.69 g K, 0.42 to 0.44 g Mg, and 0.98 to 0.88 g Na /kg of EBW gain (EBWG) for males. The daily net requirements for growth ranged from 11.93 to 11.68 g Ca, 6.12 to 5.71 g P, 1.58 to 1.63 g K, 0.41 to 0.36 g Mg, and 1.34 to 1.24 g Na /kg of EBWG for females; In the late growing period, the net macromineral requirements for maintenance were 27.03 mg Ca, 12.53 mg P, 3.72 mg Na, 7.10 mg K, and 1.42 mg Mg/kg of empty BW (EBW) for males. The net macromineral requirements for maintenance were 20.20 mg Ca, 13.50 mg P, 3.80 mg Na, 7.91 mg K, and 1.10 mg Mg/kg EBW for females.The daily net requirements for growth ranged from 11.12 to 11.43 g Ca, 5.82 to 5.93 g P,1.71 to 1.91 g K, 0.46 to 0.48 g Mg, and 0.96 to 0.92 g Na /kg of EBW gain (EBWG) for males. The daily net requirements for growth ranged from 11.79 to 12.06 g Ca, 6.04 to 6.16 g P, 1.66 to 1.74 g K, 0.40 to 0.42 g Mg, and 0.98 to 0.95 g Na /kg of EBWG for females.These results for the nutritional requirements of macro-minerals may help to formulate more balanced diets for Dorper x Hu lambs in the growth phase of 20 to 50 kg BW.2. The net trace element requirements for maintenance and growth of Dorper x Hu lambsA comparative slaughter trial was conducted to estimate the net trace element requirements for maintenance and growth of Dorper × Hu male and female lambs. The design was in accordance with the experiment 1. In the early growing period, for males and females, the daily net trace element requirements for maintenance were 356.1 and 164.1 Fe,4.3 and 3.4 Mn, 42.0 and 29.8 Cu, and 83.5 and 102.0 Zn μg/kg EBW, respectively. Net requirements for growth decreased from 65.67 to 57.27 Fe, 0.35 to 0.25 Mn, and 3.45 to 2.82 Cu and increased from 26.36 to 26.65 Zn mg/kg EBW gain (EBWG) for males. Net requirements for growth decreased from 30.66 to 22.14 Fe, 0.43 to 0.32 Mn, 2.86 to 2.18 Cu, and 27.71 to 25.83 Zn mg/kg EBWG for females; In the late growing period, for males and females, the daily net trace element requirements for maintenance were 429.3 and 310.4 Fe, 5.1 and 4.4 Mn, 48.8 and 35.7 Cu, and 94.6 and 110.3 Zn μg/kg EBW,respectively. Net requirements for growth decreased from 70.41 to 68.40 Fe and 4.31 to 4.15 mg Cu, and increased from 0.86-0.93 Mn and 33.46 to 35.20 Zn mg/kg EBW gain(EBWG) for males. Net requirements for growth decreased from 41.02 to 37.05 Fe,0.52-0.49 Mn, 3.39 to 3.10 Cu, and increased from 34.21 to 35.80 Zn mg/kg EBWG for females. This study indicated that the net trace element requirements for Dorper × Hu crossbred lambs may be different from those of purebred or other genotypes, and more data are needed for sheep in general.3. Energy and protein requirements for maintenance of Hu sheep during pregnancyThis 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 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 trialat d 40, 100, and 130 of gestation,respectively. Three groups were fed a mixed diet (Diet 1 was fed in the early gestation; Diet 2 was fed in the late gestation) either for ad libitum intake,70% or 50 % of the ad libitum intake for the duration of their gestation period. The results showed that the DMI (kg/d)increased (P < 0.05) from d 40 to 100 of gestation but then declined (P < 0.05) to d 130 of gestation. Methane energy, DE, MEI, DE/GE, ME/GE, and ME/DE were increased (P <0.05) as feeding levels increased at each stage of gestation. The methane emission rate(CH4 energy/GE) was decreased as feeding levels increased, and the CH4 energy/GE was greatest at d 100 of gestation (P < 0.05). The apparent digestibility of C and N were increased as feeding levels decreased at each stage of gestation. Apparent C digestibility was increased (P < 0.001) as days of gestation increased. Apparent N digestibility was greater (P < 0.001) at d 100 than d 40 and 130 of gestation. The methane emission (L/kg of DMI and L/kg of NDFI) was decreased as feeding levels increased at each stage of gestation (P< 0.01), and increased from d 40 to d 100 of gestation but then decreased to d 130 of gestation (P< 0.001). The CO2 to CH4 ratio was higher in 70% group than in AL and 50% groups at each stage of gestation, except for d 130 of gestation (P< 0.01), and decreased from d 40 to d 100 of gestation but then increased to d 130 of gestation (P<0.001). The daily NEm were 295.80, 310.09, and 323.59 kJ/kg0.75 of BW with a partial efficiency of ME 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/kg0 75 of BW 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.4. Dietary N-carbamylglutamate and rumen-protected L-arginine supplementation ameliorate fetal growth restriction in undernourished ewesThis study was conducted with an IUGR model to test the hypothesis that dietary NCG and RP-Arg supplementation are effective in ameliorating fetal growth restriction in undernourished ewes. Beginning on d 35 of gestation, ewes were fed a diet providing 100%of NRC-recommended nutrient requirements, 50% of NRC-recommendations, 50% of NRC recommendations supplemented with 20 g/d RP-Arg (providing 10 g/d of Arg), and 50% of NRC recommendations supplemented with 5 g/d NCG product (providing 2.5 g/d of NCG).On d 110, maternal, fetal, and placental tissues and fluids were collected and weighed. Ewe weights were lower (P< 0.05) in nutrient-restricted ewes compared with adequately fed ewes. Maternal RP-Arg or NCG supplementation did not alter (P = 0.26) maternal BW in nutrient restricted ewes. Weights of most fetal organs were increased (P<0.05) in RP-Arg-treated and NCG-treated underfed ewes compared with 50% NRC-fed ewes.Supplementation of RP-Arg or NCG reduced (P<0.05) concentrations of β-hydroxybutyrate,triglycerides,and ammonia in serum of underfed ewes but had no effect on concentrations of lactate and growth hormone.Maternal RP-Arg or NCG supplementationmarkedly improved (P<0.05) concentrations of AA (particularly arginine-family AA and branched-chain AA) and polyamines in maternal and fetal plasma and in fetal allantoic and amniotic fluidswithin nutrient restricted ewes.These novel results indicate that dietary NCG and RP-Arg supplementation to underfed ewes ameliorated fetal growth restriction, at least in part, by increasing the availability of AA in the conceptus and provide support for its clinical use to ameliorate IUGR in humans and sheep industry production.5. N-carbamylglutamate or L-arginine improved maternal and placental development in underfed ewesThe objectives were to determine how dietary NCG and RP-Arg supplementation in nutrient restricted pregnant Hu sheep would affect 1) maternal endocrine status; 2) maternal,fetal, and placental anti-oxidation capability 3) placental development. From d 35 to 110 of gestation, thirty-two Hu ewes carrying twin fetuses were allocated at random into 4 groups:100% of NRC-recommended nutrient requirements, 50% of NRC-recommendations, 50%of NRC recommendations supplemented with 20 g/d RP-Arg, and 50% of NRC recommendations supplemented with 5 g/d NCG product. The results showed that in maternal and fetal plasma and placentomes, the activities of total antioxidant capacity and superoxide dismutase were increased (P<0.05), but the activity of glutathione peroxidase and the concentration of maleic dialdehyde were decreased (P<0.05) in both NCG and RP-Arg-treated underfed ewes.The mRNA expression of vascular endothelial growth factor and Fms like tyrosine kinase 1 was increased (P < 0.05) in 50% NRC ewes than in 100%NRC ewes, and had no effect (P>0.05) in both NCG and RP-Arg-treated underfed ewes;A supplement of RP-Arg and NCG reduced (P< 0.05) concentrations of progesterone, cortisol,and estradiol 17β,had no effect on T4/T3, and improved (P< 0.05) concentrations of leptin,insulin-like growth factorl, triiodothyronine (T3),and Thyroxine (T4) in serum from underfed ewes. These results indicate that dietary NCG and RP-Arg supplementation to underfed ewes could influence maternal endocrine status, improve the maternal-fetal-placental anti-oxidation capability and promote fetal and placental development during early to late gestation.更多还原