Studies On The Dynamic Changes Of Gut-brain Peptides And Antioxidant Enzymes In SPF Chickens Infected With IBV

Based on neuro-immune-endocrine net theory, using immunohistochemistry , enzyme chemistry and immuno-electromicroscopy methods, the location and content of two important gut-brain peptides (SP, VIP) in trachea , lung ,and kidney tissues of the chickens infected with IBV were observed. The dynamic changes of SOD, GSH-PX, MDA ,N0 and NOS in the serum of chickens infected with IBV were also checked. The results showed:1.The content of serum SOD in experiment group decreased, especially on the day 5 post infection(PI) and the day 7 PI, the serum SOD content in experiment group was lower than that in control group (P<0.05). The content of serum GSH-PX decreased from the day 7 PI to the day 15 PI, but there was no significant difference between the experiment and control group (P>0.05 ) . The content of serum MDA in experiment group increased from the day 3 PI to the day 15 PI, while only on the day 5 PI, there was significant difference between the experiment group and control group (P<0.05).2. The content of serum NOS increased from the day 3 PI to the day 15 PI, but the difference between the experiment and control group was not significant (P>0. 05). From the day 3 PI, the content of serum NO began increase. And on the day 5 , 7 and 11 PI, the content of serum NO in the experiment group was respectively higher than that in control group (P<0. 05).3. The content of Substance P (SP) in trachea tissue in experiment group started to increase from the day 5 PI and on the day 5 and 7 PI, the content of SP in experiment group was significantly higher than that in control group (P<0. 05). The content of vasoactive intestinal peptide ( VIP) in trachea tissue of experiment group was higher than that in control group, especially on the day 7 and 11 PI, the content of VIP in the trachea of experiment group was significantly higher than that in control group (P <0.05) . The content of SP in kidney tissue of experiment group was higher than that of control group, especially on the day 5,7 and 11 PI, it was significantly higher than that of control group (P<0.05) . The content of VIP in kidney tissue of experiment group increased too, especially on the day 7 and11 PI, it was significantly higher than that of control group (P<0.05) . The re was no significant difference between the contents of SP and VIP of lung tissue in experiment group and those in control group.4. Ultrastructurally, after infected with IBV, lots of grume were observed on the surface of trachea tissue and the cilia of the trachea were massed. The immunohistochemistry positive reactive products of SP and VIP were significantly increased.All the results showed that the activity of SOD and GSH-PX in the chickens infected with IBV decreased. So chickens' function of clearing the free radioal descended and the balance of the neuro-immune-endorcrine system could be affected by the unnormal expression of gut-brain peptides (SP,VIP) and inflammation factor (NO) .The protection of the trachea with normal modality was also changed by the inoculation of IBV. All these factors may concurrently regulate the occurrence and development of IB. This study richered the data for the immuno-neuro-endocrine network theory and provided some new knowledge for reference of making new strategy to control IB.