精氨酸对左旋硝基精氨酸甲酯诱导猪宫内生长受限的缓解作用

Alleviation Effects of L-arginine on Intrauterine Growth Retardation of Fetal Pigs Induced by NG-nitro-L-arginine Methyl Ester Challenge

本研究旨在探讨L-精氨酸(L-Arg)对左旋硝基精氨酸甲酯(L-NAME)诱导的猪宫内生长受限的缓解作用。试验选取40头预产期相近、2～4胎次的长白×大约克夏妊娠母猪,随机分为4个处理:处理Ⅰ(正对照)、处理Ⅱ(负对照,注射L-NAME)、处理Ⅲ(L-NAME+1.0%L-Arg)和处理Ⅳ(1.0%L-Arg),每个处理10个重复,每个重复1头母猪。孕85～105d,处理Ⅱ、Ⅲ母猪连续21d于颈背部皮下多点注射2.5mL的L-NAME溶液以诱导宫内生长受限(IUGR),剂量为15.0mg/kgBW。处理Ⅰ和Ⅳ母猪则以相同方式注射等体积的生理盐水。于妊娠第85天、第105天耳静脉采血,分娩时取胎盘血液以测定一氧化氮(NO)、总一氧化氮合酶(TNOS)含量。记录窝产仔数、窝活仔数、窝仔重、窝活仔重、仔猪初生重及活仔初生重,计算IUGR发生率。结果表明:1)在妊娠后期母猪饲粮中添加1.0%精氨酸,窝产活仔数由11.20头显著提高到12.60头(P<0.05),窝活仔重由16.21kg提高至18.26kg(P<0.05),仔猪IUGR发生率由17.49%降低至6.35%(P<0.05);2)注射L-NAME的母猪窝产活仔数降低了19.64%(P<0.05),窝活仔重降低了27.14%(P<0.01),而仔猪IUGR发生率则显著提高至34.49%(P<0.01)。但在注射L-NAME的同时给母猪补充1.0%精氨酸后,窝产活仔数、窝活仔重达正常水平,仔猪IU-GR发生率与正对照组差异不显著(P>0.05);3)给妊娠母猪注射L-NAME,胎盘血清NO、TNOS合成量显著降低(P<0.01),但饲粮中补充1.0%精氨酸后,胎盘血清NO、TNOS合成量恢复至正常水平。由此可知,给妊娠期母猪饲粮中添加1.0%精氨酸后抵消或逆转了由L-NAME诱导的胎盘血清TNOS、NO合成量降低及胎猪生长受限作用,促进了胎猪在宫内的生长发育,并有效地预防了IUGR的发生。

This trial was conducted to study the alleviation effects of L-arginine on intrauterine growth retardation（IUGR）of fetal pigs induced by NG-nitro-L-arginine methyl ester（L-NAME）challenge.Forty Landrace×Large Yorkshire pregnant sows ranged from the second to the forth parity and with similar expected date of delivery were randomly divided into 4 treatments（treatments Ⅰ,Ⅱ,Ⅲ and Ⅳ）with 10 replicates per treatment and 1 sow per replicate,representing positive control,negative control,L-NAME＋1.0% L-arginine and 1.0% L-arginine,respectively.From d 85 to d 105 of gestation,gilts in treatments Ⅱ（negative control）and Ⅲ were subcutaneously injected with 2.5 mL L-NAME（15.0 mg/kg BW）in the neck and back every day in order to induce IUGR,and the gilts in treatments Ⅰ（positive control）and Ⅳ were injected the same volume of physiological saline with the same method.The serum from auricular vein at d 85 and 105 of gestation and from blood vessels of placenta of sows after farrowing were collected,and nitrogen monoxide（NO）and total nitric oxide synthase（TNOS）was then determined.The total piglets born per litter,total piglets born alive per litter,birth weight of all piglets born,birth weight of all piglets born alive,litter birth weight of all piglets born,as well as litter birth weight of all piglets born alive were recorded after farrowing,and the IUGR incidence was then counted.The results showed as follows：1）the total piglets born alive per litter（12.60 vs.11.20,P0.05）and the litter birth weight of all piglets born alive（18.26 vs.16.21,P0.05）were greater for the 1.0% L-arginine group compared with the positive control,and the IUGR incidence decreased from 17.49% to 6.35%（P0.05）.2）Compared with the control group,the total piglets born alive per litter and the litter birth weight of all piglets born alive of sows injected with L-NAME（treatment Ⅱ）were reduced by 19.64%（P0.05）and 27.14%（P0.01）,respectively.Meanwhile,the IUGR incidence was increased to 34.49%（P0.01）.However,1.0% L-arginine recovered the total piglets born alive per litter and the litter birth weight of all piglets born alive for sows injected with L-NAME to the normal level,and no significant difference in IUGR incidence was observed between the positive control group and the L-NAME＋1.0% L-arginine group（P0.05）.3）Yields of NO and TNOS in blood vessels of placenta were significantly reduced after injection with L-NAME（P0.01）.However,yields of NO and TNOS were recovered to the normal level when 1.0% L-arginine was supplemented to the diets.In conclusion,1.0% L-arginine supplemented to the diets of pregnant gilts could counteract intrauterine growth retardation induced by L-NAME challenge,enhance the growth and development of fetal pigs,and decrease the IUGR incidence.