断奶应激对仔猪免疫功能的影响

将24头21日龄仔猪分为对照组和试验组,对照组14头(28日龄不断奶),分别于21、27、30、33、36、42、49日龄屠宰,每次宰杀2头,公母各1;试验组10头(28日龄开始断奶),分别于30、33、36、42、49日龄屠宰,每次宰杀2头,公母各1.结果表明:试验组与对照组相比,①仔猪在断奶后第2、5、8天,外周血淋巴细胞百分数分别下降4.6%(P＞0.05)、27.0%(P＜0.05)和22.0%(P＜0.05);中性粒细胞百分数则分别上升10.3%(P＞0.05)、50.0%(P＜0.05)和28.9%(P＞0.05);N/L值分别升高23.4%(P＞0.05)、85.7%(P＜0.01)和58.1%(P＜0.05).②仔猪断奶后第2、5天,血清γ-球蛋白含量分别下降7.9%(P＞0.05)、4.8%(P＞0.05);在断奶后第8、14、21天分别增加2.9%(P＞0.05)、27.2%(P＜0.01)和18.2%(P＜0.05).③在免疫后第7天,仔猪血清SRBC抗体效价低1.61个滴度(P＜0.05);免疫后第14天,低0.5个滴度.④在断奶后第2、5、8、14、21天仔猪胸腺相对重量(脏器重/体重)分别下降54.6%(P＜0.05)、47.6%(P＜0.01)、48.3%(P＜0.05)、39.8%(P＞0.05)和38.8%(P＞0.05);脾脏相对重量分别下降20.4%(P＞0.05)、34.1%(P＜0.05)、34.4%(P＜0.05)、42.3%(P＜0.05)和32.1%(P＞0.05);肾上腺相对重量在断奶后第2、5、8天分别升高41.0%(P＜0.01)、28.2%(P＜0.05)和13.2%(P＞0.05).⑤组织学观察表明,试验组仔猪肾上腺皮质部肥大,整个皮质区有大量被染成空泡的脂肪微粒;同时大量红细胞散布于皮质区的束状带.

Effect of Early Weaning Stress on the Immunological Function of Piglet

Twenty-four crossbred piglets 3-week-old were divided into two groups.The fourteen piglets included in the control group did not wean.And two piglets(one male and one female) once were slaughtered at the 21 th,27 th,30 th,33 th,36 th,42 th and 49 th days,respectively,while ten piglets included in the experiment group weaned at 28 day of age and two piglets(one male and one female)were slaughtered at 30 th,33 th,36 th,42 th and 49 th day at a time,respectively.Compared with the control group,the results showed that At 2,5 and 8 days after weaning the percentage of lymphocyte was decreased by 4.6%(P>0.05),27.0%(P<0.05) and 22.0%(P<0.05),respectively;the percentage of neutrophil was increased by 10.3%(P>0.05),50.0%(P<0.05)and 28.9%(P>0.05) respectively;the value of N/L(percentage of Neutrophil/percentage of Lymphocyte) was increased by 23.4%(P>0.05),85.7%(P<0.01)and 58.1%(P<0.05).At 2 and 5 days after weaning the concentration of gamma globulin in serum was declined by 7.9%(P<0.05),4.8%(P>0.05) respectively;but it was increased by 2.9%(P>0.05),27.2%(P<0.01)and 18.2%(P<0.05)respectively at 8,14 and 21 days after weaning.At 7 and 14 days after immunization the SRBC antibody titers was decreased by 1.61 log2(P<0.05)and 0.50 log2(P>0.05).At 2,5,8,14 and 21days after weaning the relative weight of thymus was lowered by 54.6%(P<0.05),47.6%(P<0.05),48.3%(P<0.05),39.8%(P>0.05)and 38.8%(P>0.05) respectively;the relative weight of spleen was lowered by 20.4%(P>0.05),34.1%(P<0.05),34.4%(P<0.05),42.3%(P<0.05) and 32.1%(P>0.05)respectively;at 2,5,8 days after weaning the relative weight of adrenal gland was increased by 41.0%(P<0.01),28.2%(P<0.05) and 13.2%(P>0.05).The histological observation suggested that EWS caused enlargement of whole adrenal cortex,lipid infiltration of whole adrenal cortex and some haemorrhages in fascicular zone.