| Background: The importance of immune system' s regulation on nutrition metabolism has come to our researchers' mind. High immune activity leads to more nutrients waste in animals and human caused by infections and abnormal immune responses, while the influence of immunosuppression is so far unknown. According to this situation, we conducted this research work to interpret the relationship between immunosuppression and nutrition metabolism.Methods: The first work is to construct the inner competitor used in quantitative competitive PCR (Q-C-PCR) for chicken cytokines mRNA.Sequences of cytokines (IL-1beta, IL-2, IFN-gamma) were obtained form Genebank and the gene structures were analyzed in order to get proper primers and target amplified segments with restrict enzyme sites. Total RNA abstracted form broiler spleen, bursa and thymus with Trizol was reverse transcripted to cDNA and then amplified with primers respectively. The target segments were inserted into vectors. Then inserts in the constructed plasmids were digested with restrict enzymes and ligated again. The standard competitors within new plasmids were shorter than original segments from 50-80 bases which is easy to separate by electrophoresis. The sequences results of competitors confirmed the proper construction. Twenty-day-old Arbor Acres (AA) broilers were injected with cyclophosphamide (CTX) in the morning which is a known immunosuppressant in the whole research. Celiac injection with lOmg/kgBW at a time in this research was once applied and the same dosage of saline solution was used as control for injection stress. The samples used in Test 2 and Test 3 were collected from the killed animals in the first (21D), third (23D), fifth (25D), eighth (28D) and thirteenth (33D) day after injection. The analysis of the sample was conducted, including immuneorgan weight, proliferation of peripheral blood lymph cells induced by LPS and ConA respectively, quantification for 3-methyl- histidine in blood by HLPC with one-spot way, radioimmuninoassay for glucocortcoid, T3,T4, insulin and leptin and quantitative competitive PCR used for IL-lbeta, IL-2 and IFN-gamma mRNA quantifications. Apparent metabolism in Test four was studied with ninety broilers, with the same day old as previous study and each treat was replicated with five broilers, to examine the influence of immunosuppression on feed intake, body weight and feed efficiency for one week. The feed intake were recorded and fence was collected regularly everyday. Feed and fence were analyzed according to National Feed Industry Standard Rule (1994). All data was analyzed with SAS software.Results: The weight of bursa and proliferation of B cell were significant depressed by CTX (P<0.05), but there is no effect on spleen weight and T cell. CTX decreased IL-lbeta and TNF-gamma mRNA level in the bursa and spleen but not in thymus and did not affect IL-2 mRNA. Broiler serum GC (P<0. 05) and T4 were decreased and insulin (P<0. 05) and T3 were increased by CTX treated. However, leptin was not detected by human leptin RIA kit. Both body weight (P<0. 05) and feed intake were higher than other group, but feed apparent efficiency was reduced. In addition, 3-methylhistidine in the blood were higher in the CTX treated group probably due to its strong cytotoxicity.Conclusion: Depressed activity of immune system results in body weight gain, while higher food intake and lower GC level contribute to this action. IL-lbeta, TNF-gamma and GC may play critical roles in the regulation of immune system on nutrition metabolism.
|
PDF Full Text Request