Dietary plant extracts improve immune responses and growth efficiency of pigs experimentally infected with porcine reproductive and respiratory syndrome virus
Dietary plant extracts improve immune responses and growth efficiency of pigs experimentally infected with porcine reproductive and respiratory syndrome virus
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DOI：
10.2527/jas.2013-6495
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发表时间：
2013-12-01
影响因子：
3.3
通讯作者：
Pettigrew, J. E.
中科院分区：
文献类型：
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作者：
Liu, Y.;Che, T. M.;Pettigrew, J. E.
本试验研究了3种不同植物提取物对猪繁殖与呼吸综合征病毒（PRRSV）感染断奶仔猪生长性能和免疫应答的影响。采用随机完全区组设计，采用2 × 4因子设计，将64头无PRRSV的断奶仔猪（体重7.8±0.3 kg）随机分为8个处理中的1个。猪被初始体重阻断。性别和血统在不同的治疗中是平等的。第一个因素是是否有PRRSV攻击（鼻内剂量；10(5)50%组织培养感染剂量）。第二个因素采用4种饲粮：苗期基础饲粮（CON）、10 mg/kg辣椒油树脂（CAP）、大蒜植物油树脂（GAR）或姜黄油树脂（TUR）。猪在疾病收容室内饲养28 d[接种前后14 d (d 0)]。分别于第0、7、14天采血，测定总白细胞和白细胞分化数（WBC）；采集血清，采用定量PCR、PRRSV抗体滴度、肿瘤坏死因子- α (tnf - α)、白细胞介素-1 β、c反应蛋白（CRP）、酶联免疫吸附试验（ELISA）测定病毒载量。在未攻毒组，所有仔猪在接种后的整个时期均为PRRSV阴性。所有数据采用SAS的PROC mix进行分析。从第0 ~ 14天PRRSV攻毒降低了ADG、ADFI和G: F （P < 0.01）。饲喂TUR可改善prrsv感染猪0 ~ 14 d的G: F。PRRSV在第7天降低了白细胞和中性粒细胞的数量（P < 0.05），在第14天升高了白细胞和中性粒细胞的数量（P < 0.05），说明PRRSV感染猪处于弱免疫应答阶段。与con相比，GAR使PRRSV感染猪的B细胞和CD8+ T细胞增加（P < 0.05）， PRRSV攻毒使第7天的血清病毒载量、tnf - α和IL-1 β升高（P < 0.05），使第14天的血清病毒载量、CRP和Hp升高（P < 0.05），而植物提取物使PRRSV感染猪的这种增加趋势逆转（P < 0.05）。感染PRRSV的猪在第7、9、11天的直肠温度升高（P < 0.05），但喂食植物提取物的PRRSV感染猪的直肠温度低于喂食CON的猪（P < 0.05），说明饲喂植物提取物延缓了PRRSV感染引起的发热。综上所述，添加植物提取物可通过提高猪的免疫应答来减轻PRRSV的不良影响，且3种植物提取物的效果不同。添加TUR可提高PRRSV攻毒猪的饲料效率。
A study was conducted to evaluate the effects of 3 different plant extracts on growth performance and immune responses of weaned pigs experimentally infected with porcine reproductive and respiratory syndrome virus (PRRSV). A total of 64 weaned pigs (7.8 +/- 0.3 kg BW), free of PRRSV, were randomly allotted to 1 of 8 treatments in a 2 x 4 factorial arrangement with a randomized complete block design. Pigs were blocked by initial BW. Sex and ancestry were equalized across treatments. The first factor was with or without PRRSV challenge (intranasal dose; 10(5) 50% tissue culture infective dose). The second factor was represented by 4 diets: a nursery basal diet (CON), 10 mg/kg capsicum oleoresin (CAP), garlic botanical (GAR), or turmeric oleoresin (TUR). Pigs were housed in disease containment chambers for 28 d [14 d before and after the inoculation (d 0)]. Blood was collected on d 0, 7, and 14 to measure the total and differential white blood cells (WBC), and serum was collected to measure viral load by quantitative PCR, PRRSV antibody titer, tumor necrosis factor-alpha (TNF-alpha), IL-1 beta, C-reactive protein (CRP), and haptoglobin (Hp) by ELISA. In the unchallenged group, all piglets were PRRSV negative during the overall period postinoculation. All data were analyzed using PROC MIXED of SAS. The PRRSV challenge decreased (P < 0.01) ADG, ADFI, and G: F from d 0 to 14. Feeding TUR improved G: F of the PRRSV-infected pigs from d 0 to 14. The numbers of WBC and neutrophils were decreased (P < 0.05) by PRRSV on d 7 but increased (P < 0.05) by PRRSV on d 14, indicating the PRRSV-infected pigs undergo a stage of weak immune responses. Feeding GAR increased (P < 0.05) B cells and CD8+ T cells of PRRSV-infected pigs compared with the CON. Furthermore, the PRRSV challenge increased (P < 0.05) serum viral load, TNF-alpha, and IL-1 beta on d 7 and serum viral load, CRP, and Hp on d 14, but feeding plant extracts to PRRSV-infected pigs reversed (P < 0.05) this increase. Infection with PRRSV increased (P < 0.05) rectal temperature of pigs on d 7, 9, and 11, but PRRSV-infected pigs fed plant extracts had lower rectal temperature (P < 0.05) than pigs fed the CON, indicating feeding plant extracts delayed the fever caused by PRRSV infection. In conclusion, results indicate that supplementation with plant extracts reduces the adverse effects of PRRSV by improving the immune responses of pigs, and the 3 plant extracts tested here show different effects. Supplementation with TUR improved feed efficiency of pigs challenged with PRRSV.