不同营养水平饲粮对妊娠环江香猪体液游离氨基酸浓度的影响

http://dx.doi.org/10.7685/jnau.201911010

文章信息

赵越, 赵蕾, 姬玉娇, 耿梅梅, 孔祥峰

ZHAO Yue, ZHAO Lei, JI Yujiao, GENG Meimei, KONG Xiangfeng

Effects of different dietary nutrient-levels on free amino acid concentration in body fluid of pregnant Huanjiang mini-pigs

南京农业大学学报, 2020, 43(6): 1072-1078

Journal of Nanjing Agricultural University, 2020, 43(6): 1072-1078.

http://dx.doi.org/10.7685/jnau.201911010

文章历史

收稿日期: 2019-11-05

引用本文

赵越, 赵蕾, 姬玉娇, 等. 不同营养水平饲粮对妊娠环江香猪体液游离氨基酸浓度的影响[J]. 南京农业大学学报, 2020, 43(6): 1072-1078.

ZHAO Yue, ZHAO Lei, JI Yujiao, et al. Effects of different dietary nutrient-levels on free amino acid concentration in body fluid of pregnant Huanjiang mini-pigs[J]. Journal of Nanjing Agricultural University, 2020, 43(6): 1072-1078. DOI: 10.7685/jnau.201911010

不同营养水平饲粮对妊娠环江香猪体液游离氨基酸浓度的影响

赵越¹ , 赵蕾^1,2 , 姬玉娇¹ , 耿梅梅¹ , 孔祥峰^1,3

1. 中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室/动物营养生理与代谢过程湖南省重点实验室, 湖南长沙 410125;
2. 湖南农业大学动物科学技术学院, 湖南长沙 410128;
3. 中国科学院环江喀斯特生态试验站香猪研究中心, 广西环江 547100

收稿日期：2019-11-05

基金项目：国家自然科学基金项目（31772613，31572421）；中国科学院STS区域重点项目（KFJ-STS-QYZD-052）；广西科技基地和人才专项（桂科AD17195043）；湖南创新型省份建设专项（2019RS3022）

作者简介：赵越, 硕士研究生

通信作者：孔祥峰, 博士, 研究员, 博导, 研究方向为猪的孕体发育调控, E-mail:nnkxf@isa.ac.cn.

摘要：[目的]本试验旨在研究不同营养水平饲粮对妊娠母猪体液游离氨基酸浓度的影响。[方法]选用妊娠环江香猪48头，随机分为NRC饲粮组和地方猪饲粮组，每组8个重复（栏），每重复3头。分别于妊娠45和75 d，从每重复随机取1头母猪，前腔静脉采血，分离血浆；屠宰后收集每窝中最大体质量、中间体质量和最小体质量胎猪（对应）的羊水和尿囊液，测定游离氨基酸浓度。[结果]与地方猪饲粮组相比，饲喂NRC饲粮可显著提高妊娠45 d母猪血浆Leu、Lys、Gly和总氨基酸（TAA）浓度，显著提高最大体质量胎猪羊水中Leu浓度，以及妊娠75 d母猪血浆必需氨基酸（EAA）浓度（P < 0.05）；显著降低妊娠45 d母猪血浆Met浓度，妊娠75 d母猪非必需氨基酸和TAA浓度，以及妊娠45和75 d最小体质量胎猪羊水中Val和Lys浓度（P < 0.05）。与妊娠45 d相比，妊娠75 d母猪2个饲粮组各体质量胎猪羊水中Met、Lys和Ile浓度以及尿囊液中Cys浓度均显著下降（P < 0.05），尿囊液中Leu和Tau浓度显著升高（P < 0.05），地方猪饲粮组各体质量胎猪羊水中Tau浓度均显著下降（P < 0.05）。[结论]与饲喂地方猪饲粮相比，饲喂NRC饲粮可增加母猪对氨基酸的摄入，有利于胎猪的生长发育。

关键词：妊娠环江香猪营养水平血浆羊水尿囊液游离氨基酸

Effects of different dietary nutrient-levels on free amino acid concentration in body fluid of pregnant Huanjiang mini-pigs

ZHAO Yue¹, ZHAO Lei^1,2, JI Yujiao¹, GENG Meimei¹, KONG Xiangfeng^1,3

1. Key Laboratory for Agro-Ecological Processes in Subtropical Region/Hunan Provincial Key Laboratory of Animal Nutrition Physiology and Metabolism Process, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China;
2. College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China;
3. Research Center of Mini-Pig, Huanjiang Observation and Research Station for Karst Ecosystems, Chinese Academy of Sciences, Huanjiang 547100, China

Abstract: [Objectives] The present study was conducted to investigate the effects of different dietary nutrient-levels on free amino acid concentration in plasma, amniotic fluid, and allantoic fluid of pregnant sows. [Methods] Forty-eight pregnant Huanjiang mini-pigs were randomly assigned into NRC diet group and local-pig diet group, with eight replicates(pens) per group and three pigs per replicate. At 45 and 75 d of pregnancy, blood samples from one sow per replicate were collected by cranial vena cava to separate plasma. The amniotic fluid and allantoic fluid of fetuses with maximal body weight(BW), middle BW, and minimal BW per litter were collected for determining free amino acid concentration. [Results] Compared with the local-pig diet, NRC diet significantly increased(P < 0.05) the plasma concentration of Leu, Lys, Gly, and total amino acids(TAA), and the Leu concentration in amniotic fluid of fetuses with maximal BW at 45 d of pregnancy, as well as the plasma concentration of essential amino acid(EAA) at 75 d of pregnancy; while significantly decreased(P < 0.05) the plasma Met concentration at 45 d of pregnancy, the plasma concentration of nonessential amino acid and TAA at 75 d of pregnancy, as well as the concentration of Val and Lys in amniotic fluid of fetuses with minimal BW at 45 and 75 d of pregnancy. The concentration of Met, Lys, and Ile in amniotic fluid and Cys in allantoic fluid of fetuses with the same standard BW in both diet groups significantly decreased(P < 0.05) at 75 d of pregnancy, as well as the taurine(Tau) concentration in amniotic fluid of fetuses with various standard BW in local-pig diet group, while the concentration of Leu and Tau in allantoic fluid significantly increased(P < 0.05), when compared with 45 d of pregnancy. [Conclusions] These findings suggested that, compared with the local-pig diet, NRC diet could result in the growth and development of fetuses by increasing the intake of amino acids of Huanjiang mini-sows.

Keywords: pregnant Huanjiang mini-pigs nutrition level plasma amniotic fluid allantoic fluid free amino acid

胚胎损失和宫内生长受限导致母猪窝产活仔数下降、仔猪出生体质量偏低, 是影响养猪生产经济效益的重要因素^[1]。通过改善妊娠母猪的营养水平调控胎盘生长和功能以及子宫内环境, 可提高胚胎和胎儿成活率^[2]。氨基酸作为机体蛋白质、激素和一些生物信号分子的必需前体物质, 在孕体发育过程中扮演着极重要角色, 氨基酸缺乏会严重影响胎儿蛋白质的生物合成^[3]。血浆游离氨基酸可被看作动物机体的动态氨基酸营养库, 其浓度主要受饲粮营养水平、机体生理状况、养殖环境和疾病等因素的影响^[4]。母体血液中的氨基酸等营养物质经胎盘供给胎儿, 用于胎儿的生长发育^[5-6]。羊水来源于母体、胎儿和胎盘组织间的物质循环^[7], 可以为胎儿的生长发育提供氨基酸和其他生物活性分子^[1]。尿囊液中的氨基酸含量与胎儿的生长发育有关^[8]。饲粮添加精氨酸(Arg)、脯氨酸(Pro)或谷氨酸(Glu)对母猪繁殖性能和孕体发育均有一定的促进作用^[9-11]。笔者前期研究发现, 高营养水平饲粮在一定程度上可改善母猪的营养代谢, 促进其生长发育; 妊娠75 d前饲喂NRC(National Research Council, USA)饲粮有利于降低宫内发育迟缓(IUGR)的发生率^[12]。母体摄入高营养水平饲粮, 可改变羊水和尿囊液的生化参数, 促进胎猪的生长发育, 且不同体质量胎猪对蛋白质的利用效率存在差异^[13]。高营养水平饲粮能够提高母体和孕体精氨酸家族氨基酸(AFAA)的浓度, 促进其在母体和胎儿之间的转运^[14]。然而, 饲粮营养水平对妊娠母猪体液中除AFAA外的其他氨基酸浓度的影响目前尚不清楚。本试验研究不同营养水平饲粮对不同妊娠期母猪血浆以及不同体质量胎儿对应羊水和尿囊液中游离氨基酸(除AFAA外)浓度的影响, 为提高环江香猪的繁殖性能提供营养调控依据。

1 材料与方法 1.1 试验动物、分组和饲养管理

试验选用首次妊娠的环江香猪48头, 根据体质量随机分为2组, 每组8个重复(栏), 每个重复3头。试验开始前称量每头母猪的空腹体质量并记录, 统一饲喂环江香猪地方饲粮; 配种后分别饲喂NRC饲粮(参照美国NRC2012推荐需要量配制)和地方猪饲粮(参照2004版中国地方猪饲养标准和环江香猪企业饲喂标准配制)(表 1)。试验期间, 每栏母猪的总采食量为3头母猪总体质量的2.5%(实际生产中常以水拌料为主, 所以喂料量偏大)。每日08:30和17:00各饲喂1次, 自由饮水。所有试验猪按猪场饲养管理计划进行常规免疫和管理。

表 1 基础饲粮组成及营养水平(风干基础) Table 1 Composition and nutrient levels of basal diets(air-dry basis) %

组分 Components	地方猪饲粮组 Local-pig diet group	NRC饲粮组 NRC diet group	营养组成 Nutrient Levels	地方猪饲粮组 Local-pig diet group	NRC饲粮组 NRC diet group
玉米Corn	57.20	58.20	粗蛋白质Crude protein	9.77	13.11
豆粕Soybean meal	0.00	11.00	消化能²⁾ Digestible energy	12.24	14.73
麦麸Wheat bran	11.00	11.50	粗纤维Crude fiber	6.86	4.56
米糠Rice bran	13.00	4.00	粗脂肪Ether extract	5.00	9.34
苜蓿草粉Alfalfa meal	14.00	3.00	钙Ca	0.58	0.62
大豆油Soybean oil	0.00	7.50	总磷Total phosphorus	0.44	0.52
磷酸氢钙CaHPO4	1.15	1.15	赖氨酸Lys	0.83	1.11
石粉Limestone	0.79	0.79	蛋氨酸+半胱氨酸Met+Cys	0.52	0.65
食盐NaCl	0.30	0.30	苏氨酸Thr	0.50	0.65
赖氨酸Lys	0.88	0.88	色氨酸Trp	0.13	0.18
蛋氨酸Met	0.27	0.27	精氨酸Arg	0.27	0.58
苏氨酸Thr	0.33	0.33	组氨酸His	0.15	0.27
色氨酸Try	0.08	0.08	异亮氨酸Ile	0.18	0.36
预混料¹⁾ Premix	1.00	1.00	亮氨酸Leu	0.56	0.87
合计Total	100.00	100.00	苯丙氨酸Phe	0.24	0.45
			缬氨酸Val	0.24	0.42
			天冬氨酸Asp	0.52	0.96
			半胱氨酸Cys	0.16	0.22
			谷氨酸Glu	1.23	1.97
			甘氨酸Gly	0.27	0.43
			脯氨酸Pro	0.38	0.64
注:1)预混料为每千克饲粮提供The premix provided the following per kg of diet:vitamin A(VA)12 040 IU, VD₃ 2 112 IU, VE 29.7 IU, VK₃ 2.8 mg, VB₁ 1.2 mg, VB₂ 7.1 mg, VB₆ 1.3 mg, VB₁₂ 0.03 mg, 烟酸Nicotinic acid 42.9 mg, 泛酸Pantothenic acid 21.6 mg, 叶酸Folic acid 0.44 mg, 生物素Biotin 0.12 mg, 胆碱Choline 320 mg, Fe 80 mg, Cu 40 mg, Zn 140 mg, Mn 52 mg, I 0.56 mg, Co 1.4 mg, Se 0.33 mg。 2)消化能单位为MJ·kg^-1。The unit of digestible energy is MJ·kg^-1.

表选项

1.2 样品采集

分别于妊娠45和75 d, 每栏取1头母猪, 前腔静脉采血, 肝素抗凝, 3 000 r·min^-1离心10 min分离血浆, -20 ℃保存; 将采血母猪颈动脉放血处死, 解剖取出整个子宫, 用注射器分别吸取羊水和尿囊液, 称取每头胎猪的体质量, 选取每窝中最大体质量、中间体质量和最小体质量(3种标准体质量)胎猪对应的羊水和尿囊液, -20 ℃保存。

1.3 样品游离氨基酸浓度测定

样品于4 ℃解冻后取1 mL, 再向其中加入1 mL 8%水杨酸溶液, 充分混匀, 4 ℃过夜, 12 000 r·min^-1离心10 min, 取上清液, 用L-8800型全自动氨基酸分析仪(日立公司)测定游离氨基酸的浓度。

1.4 数据处理与分析

利用SPSS 18.0软件对同一妊娠期、体质量和不同饲粮组, 同一饲粮组和标准体质量、不同妊娠期的数据进行独立样本t检验。数据均以“平均值±标准误(x±SE)”表示。

2 结果与分析 2.1 饲喂不同饲粮妊娠环江香猪血浆游离氨基酸浓度的变化

由表 2可知:与地方猪饲粮组相比, NRC饲粮组妊娠45 d母猪血浆Leu、Lys、Gly和总氨基酸(TAA)的浓度以及妊娠75 d母猪血浆必需氨基酸(EAA)的浓度均显著升高(P < 0.05), 妊娠45 d母猪血浆Met浓度以及妊娠75 d母猪血浆Ala浓度、非必需氨基酸(NEAA)和总氨基酸(TAA)的浓度均显著降低(P < 0.05);相同饲粮组、不同妊娠时间母猪血浆游离氨基酸浓度无显著差异(P>0.05)。

表 2 母猪饲粮和妊娠日龄对妊娠环江香猪血浆游离氨基酸浓度的影响(n=8) Table 2 Effects of sow diets and pregnant ages on concentration of free amino acids of plasma in pregnant Huanjiang mini-pigs nmol·mL^-1

指标 Items	妊娠日龄/d Pregnant age	地方猪饲粮组 Local-pig diet group	NRC饲粮组 NRC diet group
苏氨酸Thr	45	158.84±8.73	133.04±25.88
	75	207.79±38.62	141.63±10.61
缬氨酸Val	45	276.68±17.00	234.17±18.99
	75	239.82±17.75	270.86±25.66
蛋氨酸Met	45	43.99±4.40	30.44±1.94^*
	75	40.79±3.06	33.27±3.42
异亮氨酸Ile	45	98.37±4.74	88.14±9.94
	75	91.85±6.35	102.86±8.54
亮氨酸Leu	45	179.03±12.56	232.82±14.29^*
	75	210.99±20.48	178.42±15.42
苯丙氨酸Phe	45	80.63±6.59	73.78±3.90
	75	71.90±3.48	68.97±4.48
赖氨酸Lys	45	100.09±8.34	145.16±14.51^*
	75	120.19±12.99	124.45±16.36
天冬氨酸Asp	45	17.04±1.45	13.67±1.52
	75	19.51±2.48	13.03±1.74
丝氨酸Ser	45	154.75±15.53	130.78±9.87
	75	152.13±11.96	125.43±8.74
天冬酰胺AspNH2	45	150.01±19.15	162.01±32.99
	75	119.48±7.20	122.79±21.56
甘氨酸Gly	45	921.27±45.38	1 361.01±142.62^*
	75	1 178.09±111.80	1 006.28±57.06
丙氨酸Ala	45	711.64±57.34	660.35±31.11^*
	75	796.76±39.72	658.93±20.97^*
酪氨酸Tyr	45	73.75±6.60	79.15±6.68
	75	54.23±3.68	66.89±4.61
组氨酸His	45	89.65±4.82	81.72±2.46
	75	87.70±4.31	78.61±4.15
牛磺酸Tau	45	120.94±10.35	99.68±5.41
	75	137.49±12.78	114.13±10.83
必需氨基酸EAA	45	1 043.55±18.69	997.20±35.96
	75	918.30±23.72	1 006.44±16.71^*
非必需氨基酸	45	1 914.90±22.11	2 112.84±103.22
NEAA	75	2 204.80±79.42	1 899.38±35.38^*
总氨基酸TAA	45	3 209.25±28.57	3 360.76±49.47^*
	75	3 389.36±90.60	3 157.33±33.72^*
注:1)^表示不同饲粮组间比较差异显著(P < 0.05)。Values with ^ mean significantly differ in different diet groups(P < 0.05).下同。2)EAA:Essental amino acid; NEAA:Nonesseutial amino acid; TAA:Total amino acid. The same below.

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2.2 饲喂不同饲粮妊娠环江香猪羊水游离氨基酸浓度的变化

由表 3可知:与地方猪饲粮组相比, NRC饲粮组妊娠45 d最大体质量胎猪(对应)羊水Leu浓度、最小体质量胎猪羊水天冬酰胺(AspNH₂)浓度, 妊娠75 d最大体质量胎猪羊水His浓度、中间体质量胎猪羊水Phe和Tau浓度、最小体质量胎猪羊水Phe浓度均显著升高(P < 0.05);妊娠45 d最大体质量胎猪羊水Thr、Lys、Ser、Gly、Ala、Cys、Tau和AspNH₂浓度, 中间体质量胎猪羊水Gly和Tau浓度, 最小体质量胎猪羊水Val、Lys、Asp和Tau浓度, 以及妊娠75 d最小体质量胎猪羊水Val、Met、Lys、AspNH₂、Gly、Tyr和Tau浓度均显著降低(P < 0.05)。

表 3 母猪饲粮和妊娠日龄对不同体质量胎猪对应环江香猪羊水游离氨基酸浓度的影响(n=8) Table 3 Effects of sow diets and pregnant ages on amniotic fluid concentration of free amino acids in Huanjiang mini-pigs corresponding to the different fetus body weight(BW) nmol·mL^-1

指标 Items	妊娠日龄/d Pregnant age	地方猪饲粮组Local-pig diet group			NRC饲粮组NRC diet group
指标 Items	妊娠日龄/d Pregnant age	最大体质量 Maximal BW	中间体质量 Middle BW	最小体质量 Minimal BW	最大体质量 Maximal BW	中间体质量 Middle BW	最小体质量 Minimal BW
苏氨酸Thr	45	70.87±5.46	39.81±3.26	50.77±6.59	42.71±5.00^*	36.28±3.52	45.74±6.34
	75	54.39±5.10	48.18±4.73	51.67±5.32	61.47±8.29	42.85±3.28	48.74±5.85
缬氨酸Val	45	65.65±9.14	62.20±6.02	115.81±8.09^a	60.82±7.96	47.80±6.37	42.77±7.19^*
	75	46.46±4.06	46.45±6.33	48.09±3.47^b	41.19±3.54	54.14±5.32	31.25±4.52^*
蛋氨酸Met	45	30.74±2.54^a	24.55±3.45^a	39.87±4.22^a	25.78±4.83^a	22.43±3.19^a	32.80±5.06^a
	75	15.26±1.59^b	11.61±1.36^b	18.19±2.01^b	12.62±0.92^b	14.17±1.48^b	12.00±0.89^*b
异亮氨酸Ile	45	37.65±2.09^a	35.74±4.39^a	33.58±4.05^a	32.70±4.11^a	25.43±2.58^a	34.83±6.82^a
	75	11.06±0.84^b	9.09±1.55^b	11.83±1.38^b	8.03±1.02^b	7.48±1.01^b	8.58±0.76^b
亮氨酸Leu	45	25.15±2.14	35.60±6.42	54.78±10.07^a	47.26±5.36^*a	36.05±3.23^a	65.57±5.74^a
	75	20.46±1.09	23.65±2.01	21.52±1.73^b	25.01±2.95^b	21.83±1.97^b	28.62±3.33^b
苯丙氨酸Phe	45	15.29±1.60	16.59±1.44^a	23.07±2.07^a	15.58±1.53	16.45±1.62	17.83±1.28
	75	9.50±0.85	8.31±0.45^b	10.81±1.18^b	10.67±1.40	11.10±1.26^*	16.34±1.02^*
赖氨酸Lys	45	233.88±28.57^a	162.41±26.68^a	230.97±35.62^a	155.64±5.90^*a	136.82±15.55^a	103.02±17.6^*a
	75	71.57±8.64^b	66.53±7.52^b	112.09±6.92^b	79.67±6.88^b	83.89±5.70^b	64.58±5.14^*b
天冬氨酸Asp	45	9.78±1.24^b	10.81±0.97	17.22±0.79	8.58±1.27	11.15±1.77	13.34±0.63^*
	75	13.21±1.31^a	12.70±1.39	15.76±1.78	12.60±1.25	10.67±0.73	13.04±0.89
丝氨酸Ser	45	192.91±6.90^a	164.31±11.50^a	217.20±9.53^a	118.34±8.33^*a	160.00±6.65^a	255.98±24.25^a
	75	54.15±5.05^b	57.44±7.05^b	64.60±6.80^b	59.98±5.55^b	73.95±7.18^b	63.97±5.69^b
天冬酰胺AspNH₂	45	135.02±8.13^a	119.59±14.80^a	139.39±10.40^a	71.95±6.55^*	81.68±4.24	188.38±19.05^*a
	75	62.28±6.28^b	55.55±7.11^b	75.36±2.76^b	64.42±4.59	67.90±3.85	52.95±4.99^*b
甘氨酸Gly	45	191.33±11.74	162.40±16.98	354.64±142.61	137.13±7.44^*	101.41±2.97^*	277.36±30.51^a
	75	169.66±10.37	156.21±17.41	194.52±24.60	160.63±17.63	173.19±20.27	129.81±9.98^*b
丙氨酸Ala	45	462.24±44.64	329.41±18.29	616.14±67.32^a	311.91±19.63^*	282.28±28.56	430.61±70.81^a
	75	321.53±26.37	321.55±25.01	254.25±28.71^b	290.00±17.09	328.33±21.47	240.27±12.69^b
酪氨酸Tyr	45	18.10±2.32	15.760±3.55	25.34±6.81	17.56±1.62	23.64±5.30	17.27±5.17
	75	10.82±1.14	10.66±1.41	12.40±1.21	8.47±1.55	9.26±1.49	7.19±1.77^*
半胱氨酸Cys	45	23.40±2.45^a	14.83±2.61	29.56±5.31^a	10.37±0.82^*	11.61±2.33	20.34±3.73
	75	12.84±1.07^b	12.18±0.77	12.18±1.22^b	10.44±0.82	9.77±1.40	9.10±1.31
组氨酸His	45	13.35±2.40	21.16±2.36	27.50±4.81	14.45±2.33	15.11±1.82	17.78±6.34
	75	14.70±1.78	17.59±2.31	14.51±0.92	24.30±2.16^*	20.29±2.77	19.34±2.50
牛磺酸Tau	45	55.99±4.70^a	50.20±2.35^a	62.54±2.77^a	37.67±2.38^*	35.94±1.88^*	27.86±4.57^*
	75	37.25±2.03^b	39.70±2.91^b	38.12±2.37^b	43.54±3.36	51.75±5.44^*	30.96±1.74^*
注:不同小写字母表示不同妊娠日龄间差异显著(P < 0.05)。下同。 Note:Values with different lowercase letters significantly differ at different pregnant age(P < 0.05). The same below.

表选项

与同一标准体质量的妊娠45 d胎猪相比, 妊娠75 d时地方猪饲粮组最大体质量胎猪羊水Asp浓度显著升高(P < 0.05);最大体质量胎猪羊水Met、Ile、Lys、Ser、AspNH₂、Cys和Tau浓度, 中间体质量胎猪羊水Met、Ile、Phe、Lys、Ser、AspNH₂和Tau浓度, 最小体质量胎猪羊水Val、Met、Ile、Leu、Phe、Lys、Ser、AspNH₂、Ala、Cys和Tau浓度均显著降低(P < 0.05)。妊娠75 d时NRC饲粮组最大体质量胎猪羊水Leu、Met、Ile、Lys和Ser浓度, 中间体质量胎猪羊水Met、Ile、Leu、Lys和Ser浓度, 最小体质量胎猪羊水Met、Ile、Leu、Lys、Ser、AspNH₂、Gly和Ala浓度均显著降低(P < 0.05)。

2.3 饲喂不同饲粮妊娠环江香猪尿囊液游离氨基酸浓度的变化

由表 4可知:与地方猪饲粮组相比, NRC饲粮组妊娠45 d最大体质量胎猪尿囊液Leu浓度、中间体质量胎猪尿囊液Leu和His浓度以及最小体质量胎猪尿囊液Lys、Asp、Ser、AspNH₂和Tau浓度, 妊娠75 d最大体质量胎猪尿囊液Thr、Val、Met、Ile、Leu、Phe、Lys、Asp、Ser、AspNH₂、Ala、Cys和His浓度, 中间体质量胎猪尿囊液Thr、Ile、Lys、Cys和His浓度以及最小体质量胎猪尿囊液Thr、Val、Met和Asp浓度均显著升高(P < 0.05);妊娠45 d最大体质量胎猪尿囊液Met浓度, 中间体质量胎猪尿囊液Val、Met、Phe、Ala、Tyr和Tau浓度, 最小体质量胎猪尿囊液Ile、Leu、Phe、Ala和Cys浓度, 以及妊娠75 d中间体质量胎猪尿囊液Met、Leu和Phe浓度, 最小体质量胎猪尿囊液Ile、Phe、Cys、Tyr和His浓度均显著降低(P < 0.05)。

表 4 母猪饲粮和妊娠日龄对不同体质量胎猪对应环江香猪尿囊液游离氨基酸浓度的影响(n=8) Table 4 Effects of sow diets and pregnant ages on allantoic fluid concentration of free amino acids in Huanjiang mini-pigs corresponding to the different fetus body weight(BW) nmol·mL^-1

指标 Items	妊娠日龄/d Pregnant age	地方猪饲粮组Local-pig diet group			NRC饲粮组NRC diet group
指标 Items	妊娠日龄/d Pregnant age	最大体质量 Maximal BW	中间体质量 Middle BW	最小体质量 Minimal BW	最大体质量 Maximal BW	中间体质量 Middle BW	最小体质量 Minimal BW
苏氨酸Thr	45	168.87±7.97^a	175.53±14.56^a	283.10±19.58^a	256.23±50.92^a	319.41±52.87^a	220.26±49.12
	75	67.35±6.97^b	63.08±4.03^b	106.05±7.83^b	162.46±15.00^*b	105.94±16.96^*b	139.93±14.44^*
缬氨酸Val	45	28.35±1.74	172.57±16.51^a	29.60±0.80^a	49.07±6.17^*	58.50±4.24^*	72.38±2.25
	75	37.32±3.04	38.04±2.92^b	12.04±0.74^b	57.10±4.69^*	41.90±5.27	55.08±5.20^*
蛋氨酸Met	45	22.59±4.20^a	43.86±3.28^a	6.26±0.81	11.81±1.01^*	11.00±0.63^*	12.95±1.85
	75	12.18±1.22^b	16.34±2.01^b	8.89±1.10	21.98±1.78^*	10.47±1.49^*	24.65±3.15^*
异亮氨酸Ile	45	15.81±2.46^a	19.94±2.39^a	28.26±2.46^b	17.41±1.61	25.10±1.57	18.96±3.21^*
	75	7.47±0.65^b	8.62±0.64^b	70.58±7.93^a	17.66±1.17^*	24.60±1.12^*	22.57±1.80^*
亮氨酸Leu	45	17.71±1.34^b	23.34±1.23^b	36.70±16.83^b	29.08±1.59^*b	28.05±1.23^*b	22.47±3.35^*b
	75	38.97±2.70^a	67.33±7.35^a	40.19±15.53^a	70.68±3.60^*a	49.55±3.58^*a	52.08±4.88^a
苯丙氨酸Phe	45	7.01±0.88	16.37±1.31	25.62±1.73	5.74±0.83	5.67±0.51^*	5.75±0.59^*
	75	6.74±0.72	18.85±2.15	39.47±1.34	10.31±0.70^*	10.42±0.85^*	15.19±1.08^*
赖氨酸Lys	45	727.96±38.47^a	917.78±47.69^a	648.87±65.47^a	968.45±85.25^*	1077.86±101.21	743.12±18.88^*a
	75	394.68±32.11^b	352.41±13.12^b	42.53±2.27^b	942.57±25.02^*	965.65±22.73^*	421.01±12.38^b
天冬氨酸Asp	45	58.48±2.97	65.85±5.21^a	17.35±0.91	60.35±2.51^b	71.19±3.27	56.91±5.39^*b
	75	50.79±5.08	43.85±3.36^b	13.20±2.30	100.92±16.58^*a	45.63±6.28	79.71±16.39^*a
丝氨酸Ser	45	214.44±20.25	258.98±44.41	79.52±4.93^a	233.89±36.37	286.06±40.03	161.19±15.41^*
	75	170.77±18.05	177.27±16.54	15.95±2.69^b	279.59±32.08^*	156.68±14.10	232.03±33.60
天冬酰胺AspNH₂	45	234.74±8.10^a	222.03±26.28^a	40.74±3.63	326.73±55.16^a	249.40±22.25^a	182.45±21.52^*
	75	97.62±11.01^b	155.14±23.98^b	47.88±10.68	176.74±26.52^*b	181.31±17.70^b	145.38±11.26
丙氨酸Ala	45	116.66±9.52	284.86±29.94^a	234.62±3.95	231.25±23.53^*b	147.50±13.62^*	146.52±20.32^*
	75	145.18±10.47	202.29±22.40^b	266.92±8.31	402.77±51.00^*a	159.62±16.20	192.41±34.84
半胱氨酸Cys	45	30.75±3.42^a	37.10±4.23^a	173.12±9.01^a	63.55±5.28^*a	49.04±2.59^a	39.93±4.91^*a
	75	13.81±1.18^b	17.39±1.97^b	60.77±5.77^b	26.82±4.04^*b	27.46±1.52^*b	19.26±1.22^*b
酪氨酸Tyr	45	22.84±3.09	41.07±2.14^a	12.06±0.70	27.86±1.95	28.18±1.52^*	28.64±1.82
	75	14.85±0.91	21.10±3.02^b	21.53±7.06	17.14±1.55	21.89±0.90	18.71±2.50^*
组氨酸His	45	53.86±4.73^a	90.38±4.48^a	237.53±16.35^a	90.22±8.00^*	116.55±4.11^*a	167.46±14.07^a
	75	27.02±1.89^b	27.86±1.28^b	103.84±3.87^b	63.45±5.38^*	55.97±2.43^*b	52.17±2.92^*b
牛磺酸Tau	45	168.08±21.80^b	237.57±17.60^b	119.60±9.07^b	200.48±32.90^b	136.74±19.97^*b	143.14±16.56^*b
	75	349.41±66.21^a	312.31±54.89^a	333.35±29.81^a	800.59±199.49^a	351.65±81.03^a	305.41±66.36^a

表选项

与同一标准体质量的妊娠45 d胎猪相比, 妊娠75 d时地方猪饲粮组最大体质量胎猪尿囊液Leu和Tau浓度, 中间体质量胎猪尿囊液Leu和Tau浓度, 最小体质量胎猪尿囊液Ile、Leu和Tau浓度均显著升高(P < 0.05);最大体质量胎猪尿囊液Thr、Met、Ile、Lys、AspNH₂、Cys和His浓度, 中间体质量胎猪尿囊液Thr、Val、Met、Ile、Lys、Asp、AspNH₂、Ala、Cys、Tyr和His浓度, 以及最小体质量胎猪尿囊液Thr、Val、Lys、Ser、Cys和His浓度均显著降低(P < 0.05)。妊娠75 d时NRC饲粮组最大体质量胎猪尿囊液Leu、Asp、Ala和Tau浓度, 中间体质量胎猪尿囊液Leu和Tau浓度, 最小体质量胎猪尿囊液Leu、Asp和Tau浓度均显著升高(P < 0.05);最大体质量胎猪尿囊液Thr、AspNH₂和Cys浓度, 中间体质量胎猪尿囊液Thr、AspNH₂、Cys和His浓度, 最小体质量胎猪尿囊液Lys、Cys和His浓度均显著降低(P < 0.05)。

3 讨论

Leu可以通过增强翻译起始复合物(mRNA-tRNA-elF-核糖体)的形成^[15]和激活mTOR的磷酸化^[16-17]促进蛋白质的表达, 还可通过其代谢产物β-羟基-β-甲基丁酸(β-hydroxy-β-methylbutyrate, HMB)发挥作用, 防止肌肉蛋白质降解^[18]。近期研究发现^[19], 在育肥猪饲粮中添加质量分数为1%的Leu显著提高了育肥猪股二头肌质量, 且其质量与Leu浓度呈正相关。本研究中, 与地方猪饲粮组相比, NRC饲粮可显著提高妊娠45 d母猪血浆和最大体质量胎猪羊水Leu浓度, 可能是因为NRC饲粮中Leu浓度比地方饲粮高55.36%, 提示NRC饲粮能为妊娠早期胎猪提供充足的Leu用于骨骼肌蛋白质的合成, 使胎儿窝重和个体体质量显著增加^[10], 这与上述研究结果一致。Met作为猪饲粮的第2或第3限制性氨基酸, 在生长猪饲粮中额外添加Met可显著改善其蛋白质沉积和生长性能, 降低养殖成本^[20]。本研究中, NRC饲粮组母猪妊娠45 d血浆Met浓度显著高于地方猪饲粮组, 表明NRC饲粮可在妊娠前期为胚胎发育和胎盘生长提供充足的Met; 2个饲粮组妊娠75 d各标准体质量胎猪对应羊水中Met浓度均显著低于妊娠45 d, 提示妊娠后期胎儿对Met的需求增加。另外, 饲喂NRC饲粮母猪妊娠45 d时血浆Lys和Gly浓度显著升高, 本试验使用的NRC饲粮中Lys和Gly含量分别比地方猪饲粮高33.73%和59.26%, 提示血浆与饲粮中Lys和Gly水平呈显著正相关, 这与高春起等^[21]的报道相似。

EAA对于维持动物机体氮平衡和保证孕期胎儿的正常生长发育尤为重要, 且EAA仅能从食物中直接获取。本研究中, 与地方饲粮组相比, NRC饲粮显著提高了妊娠75 d母猪血浆EAA浓度, 提示NRC饲粮能为妊娠后期蛋白质合成和胎儿的生长发育提供更充足的EAA。同时, NRC饲粮显著提高了妊娠45 d母猪血浆TAA的浓度, 表明NRC饲粮也更利于妊娠前期胎儿组织器官的分化和发育。然而, 本研究中, NRC饲粮显著降低了妊娠75 d母猪血浆TAA的浓度, 这可能与该时期NEAA浓度的显著降低有关, 猜测两者浓度的降低可能与妊娠后期胎猪的快速生长及其体内NEAA的代谢机制相关, 具体原因还有待进一步研究。

另有研究表明, 妊娠后期胎儿体质量和蛋白质含量分别比妊娠前期提高了5和18倍, 提示妊娠后期母体对氨基酸的需要量显著增加^[22]。本试验中, 妊娠后期2个饲粮组各标准体质量胎猪对应尿囊液中Leu浓度均显著升高, 提示胎儿对Leu的需要主要在妊娠前期; 羊水中Met、Lys和Ile以及尿囊液中Cys浓度均显著下降, 提示妊娠后期快速生长的胎儿对这几种氨基酸的需求量增加, 这与Soenke等^[22]的报道相似。Tau是人和动物的一种条件性必需氨基酸, 能够预防IUGR(胎儿宫内生长迟缓)的发生^[23]。本研究结果显示, 妊娠后期地方猪饲粮组各标准体质量胎猪羊水中Tau浓度显著下降, 而NRC饲粮组无显著变化, 猜测妊娠后期胎儿对Tau的需要量增加, 而地方猪饲粮组母猪血浆中Tau水平不能满足胎儿生长发育的需要; 2个饲粮组各标准体质量胎儿尿囊液中Tau浓度均显著升高, 提示妊娠75 d胎猪蛋白质降解速率增加, 产生较多的Tau排放至尿囊液中。综上所述, 与饲喂地方猪饲粮相比, 饲喂NRC饲粮可提高环江香猪母猪对氨基酸的摄入, 有利于胎猪的生长发育。

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