母猪妊娠末期背膘厚度对产仔性能和胎盘脂质氧化代谢的影响

本试验旨在探讨母猪妊娠末期背膘厚度对产仔性能和胎盘脂质氧化代谢的影响,以探索母猪妊娠期脂肪沉积与繁殖性能的关系。本试验度量了846头经产大白母猪妊娠第109天时的背膘厚度,并分为3组,背膘厚度≤18 mm的为第1组(母猪192头),背膘厚度为19~22 mm的为第2组(母猪265头),背膘厚度≥23 mm的为第3组(母猪389头)。记录母猪分娩后的产仔性能,测定胎盘组织中脂质、氧化产物水平及抗氧化酶活性。结果表明:1)尽管母猪妊娠末期背膘厚度对总产仔数、产活仔数及木乃伊数无显著影响(P0.05),但显著影响了死胎数、初生窝重、初生头重和胎盘效率(P0.05)。其中,第2组的初生头重、初生窝重及胎盘效率显著高于其他2组(P0.05);第2组的死胎数显著低于第1组(P0.05),与第3组差异不显著(P0.05)。值得注意的是,母猪妊娠末期背膘厚度显著影响每窝初生重≤0.9 kg的仔猪数和每窝初生重≤1.0 kg的仔猪数(P0.05),第3组的每窝初生重≤0.9 kg的仔猪数和每窝初生重≤1.0 kg的仔猪数均显著高于其他2组(P0.05)。2)在第3组的胎盘组织中,不仅甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)及游离脂肪酸(FFA)的水平显著高于其他2组(P0.05),而且丙二醛(MDA)和活性氧(ROS)水平也显著高于其他2组(P0.05),同时超氧化物歧化酶(SOD)活性显著低于其他2组(P0.05)。3)妊娠末期母猪胎盘组织中ROS水平与总产仔数、初生窝重及胎盘效率呈显著负相关(P0.05),而MDA水平与总产仔数呈显著负相关(P0.05)。由此可知,母猪妊娠末期背膘厚度与产仔性能密切相关。妊娠末期维持背膘厚度在19~22 mm,母猪可获得较高的产仔性能;背膘厚度≤18 mm时,会增加死胎数;而背膘厚度≥23 mm时,会引起胎盘组织中脂质过度沉积,从而加剧胎盘氧化应激的发生。

Effects of Backfat Thickness of Sows at the End of Gestation on Litter Performance and Placental Lipid Oxidative Metabolism

The present study was conducted to investigate the effects of backfat thickness of sows at the end of gestation on litter performance and placental lipid oxidative metabolism, and thus to explore the relationship be?tween fat deposition and reproductive performance in gestational sows. At day 109 of gestation, the backfat thickness of 846 multiparous Large White sows was measured and the sows were divided into three groups on the basis of the backfat thickness:backfat thickness≤18 mm for the first group ( 192 sows) , backfat thickness was 19 to 22 mm for the second group ( 265 sows) , and backfat thickness≥23 mm for the third group ( 389 sows) . The litter performance of sows was recorded, and the levels of lipids, oxidation products and antioxi?dant enzyme activities in placenta were determined. The results showed as follows:1) although the total num?ber of born, number born alive and mummy number were not significantly affected by the backfat thickness of sows at the end of gestation ( P>0.05) , but the stillbirth number, litter weight at birth, piglet weight at birth and placental efficiency were significantly affected ( P<0.05) . Sows of the second group had significantly high?er litter weight at birth, piglet weight at birth and placental efficiency than those of the other two groups ( P<0.05) , and had significantly lower stillbirth number than that of the first group ( P<0.05) , but with no signifi?cant difference compared with the third group ( P>0.05) . It is noteworthy that the number of piglet with birth weight≤0.9 kg and the number of piglet with birth weight≤1.0 kg were also significantly affected by the back?fat thickness of sows at the end of gestation (P<0.05). The number of piglet with birth weight≤0.9 kg and the number of piglet with birth weight≤1. 0 kg of the third group were significantly higher than those of the other two groups ( P<0.05) . 2) Compared with the first and second groups, there were significant increases in the levels of triglyceride ( TG) , low density lipoprotein cholesterol ( LDL?C) , free fatty acid ( FFA) , malon?dialdehyde ( MDA) and reactive oxygen species ( ROS) in the placenta of the third group ( P<0.05) . Moreo?ver, superoxide dismutase ( SOD) activity in the placenta of the third group was significantly lower than that of the other two groups ( P<0.05) . 3) The level of ROS in the placenta had a significant negative correlation with the total number born, litter weight at birth and placental efficiency ( P<0.05) . Furthermore, a significant neg?ative correlation was detected between the level of MDA in the placenta and total number born (P<0.05). Taken together, backfat thickness of sows at the end of gestation has a significant impact on litter performance. The backfat thickness of sows at the end of gestation is 19 to 22 mm to attain a high litter traits. When the back?fat thickness≤18 mm, the stillbirth number is increased. Nevertheless, the backfat thickness≥22 mm pro?motes excessive placental lipid deposition, exacerbates the oxidative stress in the placenta.