Effect Of Transportation Stress On Immune-Related Factors Of Crossbred Piglets

In recent years, with the improvement of pig farming industry, the long distance transport of pigs becomes more and more common. But at the same time, the transportation, as a kind of stress, brings more and more negative effects on the swine, such as the sudden death during the transportation. Many studies had showed that the pig deaths in transport process were directly associated with transport stress due to the suppression of the immune function. Stress can affect the immune function of animals by neuron-endocrine-immunity network. In this paper, effect of transport stress on the immune function and its control measures in pigs will be explored from the perspective of cytokines.Nine pigs castrated F2offspring of Landrace and Yorkshire parents and kept at the same environment were randomly divided into2groups, Group A (transport group, n=6) and Group B (control group, n=3). In the transportation trial, Group A was transported from KangLe pig farm in Changzhou city to Nanjing Agriculture University on the highway for2hours (outdoor temperature was18-25℃, there was no drinking water and feeding during transport stress). At the completion of specific transport stress, the pigs were taken blood and serum samples for biochemical detection and the quantitative detection of cytokines. Liver, spleen, kidney, mesenteric lymph nodes and inguinal lymph nodes were quickly removed after transport and used to investigate mRNA expression of immune-related proteins in these organs in the transport-stressed pigs.In order to investigate the changes of serum biochemical indexes in pigs during2hours transport, we determined TP, ALB, GLB, ALT, AST, ALP, Urea, GLU, TG, CHOL and LDH level. The results showed:there were no significant differences in TP, ALB, GLB, GLU, TG and CHOL level during2hours transport; the level of ALT and ALP were significantly increased30minutes after transport compared with before transport (P<0.05); the level of Urea, LDH and AST were significantly increased during transporting and30 minutes after transport (P<0.01).In order to examine antibody and cytokine levels of pigs under transport stress, we determined the IL-1β, IL-2, IL-4, IL-6, IL-10, IFN-y levels in sera and the blocking rate of CSFV antibody ELISA. The results showed:IL-1β level was significantly decreased when the pigs were transported for1h,2h and30min before end of transport (P<0.01); the IL-2level went down with the duration of transportation, and went down to the lowest point when transported for1h, and then increased again. The IL-2level at30minutes after transport was significantly higher than that at transport for1h (P<0.05); the level of IFN-y was significantly increased when transport for1h and30min after transport compared with before transport (P<0.01); There were no significant differences in IL-4, IL-6and IL-10levels, and the blocking rate of CSFV antibody ELISA during2h transport (P>0.05).In order to understand the change of immune function of transport-stressed pigs, using real-time fluorescence quantitative RT-PCR technology, the HSP90in liver and the TLR2in mesenteric lymph nodes and its corresponding receptor mRNAs transcription levels were determined. The results showed:after2h transport stress, the expression of HSP90in liver was significantly decreased compared with control group (P<0.05); The TLR2in mesenteric lymph nodes and its corresponding receptor mRNAs transcription level was decreased compared with control group, but there was no significant differences (P>0.05).The above results demonstrated that the immune function of piglets was enhanced under1h transport stress. The concentration of HSP70mRNA might be a hallmark to determine stress.