He Y, Deen J, Shurson G C, Wang L, Chen C, Keisler D H, Li Y Z
J Anim Sci. 2016 May;94(5):2103-16. doi: 10.2527/jas.2015-0005.
Pigs that grow slower than their contemporaries can cause complications for animal welfare and profitability. This study was conducted to investigate factors that may contribute to slow growth of pigs. Pigs ( = 440) farrowed by 65 sows were monitored from birth to market. Pigs were categorized as slow, average, and fast growers based on market weight adjusted to 170 d of age (slow growers were <105 kg, average growers were between 105 and 125 kg, and fast growers were >125 kg). Blood samples were collected from 48 focal pigs at 9 and 21 wk of age and analyzed for hormone and free AA concentrations. Data were analyzed using the Mixed and Logistic procedures of SAS. Slow-growing pigs accounted for 10% of pigs marketed, average growers accounted for 49% of pigs marketed, and fast growers accounted for 41% of pigs marketed. Compared with fast growers, slow growers were lighter at birth ( < 0.01), at weaning ( < 0.01), and at nursery exit ( < 0.01) and had less backfat ( < 0.01) and smaller loin muscle area ( < 0.01) at marketing at 21 wk of age. Slow growers had lower plasma concentrations of IGF-1 ( = 0.03) and insulin ( < 0.001) during the nursery period and lower concentrations of leptin ( < 0.001) and insulin ( < 0.001) during the finishing period compared with average and fast growers. Serum concentrations of several essential, nonessential, and total free AA were less for slow growers during both the nursery and finishing periods compared with average and fast growers. Gilts were more likely to become slow growers than barrows (odds ratio = 2.17, 95% confidence interval = 1.19 to 3.96, = 0.01). Litter size and parity of the pigs' dam were not associated with slow growth. These results suggest that low concentrations of IGF-1, insulin, leptin, and AA may contribute to or be associated with slow growth in pigs.
生长速度比同代猪慢的猪会给动物福利和养殖效益带来问题。本研究旨在调查可能导致猪生长缓慢的因素。对65头母猪所产的440头仔猪从出生到上市进行监测。根据调整到170日龄时的上市体重，将猪分为生长缓慢型、生长平均型和生长快速型（生长缓慢型猪体重<105千克，生长平均型猪体重在105至125千克之间，生长快速型猪体重>125千克）。在9周龄和21周龄时从48头重点仔猪采集血样，分析激素和游离氨基酸浓度。使用SAS的混合模型和逻辑回归程序分析数据。生长缓慢型猪占上市猪的10%，生长平均型猪占上市猪的49%，生长快速型猪占上市猪的41%。与生长快速型猪相比，生长缓慢型猪出生时体重较轻（P<0.01）、断奶时体重较轻（P<0.01）、保育期结束时体重较轻（P<0.01），在21周龄上市时背膘较薄（P<0.01）、腰肌面积较小（P<0.01）。与生长平均型和生长快速型猪相比，生长缓慢型猪在保育期血浆IGF-1浓度较低（P = 0.03）、胰岛素浓度较低（P<0.001），在育肥期瘦素浓度较低（P<0.001）、胰岛素浓度较低（P<0.001）。与生长平均型和生长快速型猪相比，生长缓慢型猪在保育期和育肥期血清中几种必需、非必需和总游离氨基酸浓度均较低。小母猪比阉公猪更有可能成为生长缓慢型猪（优势比 = 2.17，95%置信区间 = 1.19至3.96，P = 0.01）。仔猪窝产仔数和母猪胎次与生长缓慢无关。这些结果表明，IGF-1、胰岛素、瘦素和氨基酸浓度较低可能导致或与猪生长缓慢有关。
