The Effects Of Probiotics And β-dextran On Physiological And Biochemical Indexes, Immunity And Expression Of HSP70in Royal Chickens Undergoing Cold Stress

Cold stress is a problem occurring commonly in farms of high latitude region for breeding; particularly it could severely harm newborn animals born in the early spring brood. The royal chicken is a kind of precious poultry, have a good breeding prospect, but no information on effects of the cold stress on the physiological and biochemical and immune function index has been reported in details. In this paper, health royal chickens were chosen to study dynamic change in physiological and biochemical indexes including growth, blood parameters and serum biochemical indexs under condition of cold stress with lowering10℃than normal temperature, and dynamic changes in leukocyte differential count, mast cell number and IL-2mRNA and Hsp70mRNA expression in some immune organs; meanwhile to observe the effect of probiotics and beta dextran treatment on these indicators. This paper also disclose whether new type of feed additives probiotics and glucan with function of immune regulation could resist to cold stress. The experiment results were as following:(1)The probiotics and glucan treatment significantly affect physiological and chemical indicators the royal chicks undergoing cold stress. At4h after acute cold stress, spleen index of chicks was increased significantly, and it was markedly decreased by probiotics treatment, and Harderian gland index increased significantly by probiotics treatment. Glucan adding for3d significantly increased the spleen index of chicks undergoing cold stress. Acute cold stress can obviously cause chicks fluctuations of hematology parameters such as hemoglobin, the red and white blood cells amount, probiotics processing have obvious role of two ways adjustment, make it tend to balance. Cold stress result in significant fluctuations change of serum y-glutamyl transpeptidase (r-GT), lactate dehydrogenase (LDH) and creatine kinase (CK) activity, and adding probiotics and glucan have obvious feedback function. At4hours after acute stress, treatment of probiotics increased superoxide dismutase (SOD) activity, declined glutamic-pyruvic transaminase (GPT) activity, this suggests that probiotics can increase chicks the ability of antioxidition and liver aid.(2)The probiotics and glucan treatment significantly affect changes in leukocyte differential count, mast cell number and IL-2mRNA expression in some immune organs of the royal chicks undergoing cold stress. White blood cells classification results showed that during the acute cold stress, leukocyte differential count had significant fluctuations change, the number of basophilic granulocyte and neutrophil/lymphocyte (H/L) ratio were increased obviously. After cold adaptation lymphocyte number was significantly increased, neutrophil and H/L ratio significantly decreased.mast cells histologic dyeing count results showed that, the acute stress cold caused the increase of mast cells in Harderian glands, and probiotics and glucan adding could bidirectional regulate mast cells quantity; Cold stress reduced the number of mast cells within the thymus, probiotics treatment coordinated the number of it; probiotic bacteria and glucan adding can up-regulate the number of mast cells in bursa of Fabricius and spleen. RT-PCR results showed that IL-2mRNA expression in the spleen had a smarked change within24h post-cold stress, firstly dropping then rising, probiotics treatment had no obvious effect, and its expression level increased significantly after15d of adding glucan, this showed that glucan could adjust immune function of spleen in chick. IL-2mRNA expression in the thymus increased significantly at12to24h after stress, and obviously decreased at chronic stress and cold adapt stage. Probioticsand glucan adding play an role of up-regulation. IL-2mRNA expression changes in bursa of Fabricius was similar to that in thymus. These results suggest that cold stress obviously influenced the cellular immune function in chick, and probiotics and glucan can enhance chickens the ability of resistance to cold stress, improve the cellular immune function in chick undergoing cold stress.(3) The probiotics and glucan treatment significantly affected changes in HSP70mRNA expression in spleen, thymus and bursa of Fabricius in royal chicken under cold stress state.RT-PCR results showed that at4h post-cold stress, HSP70mRNA expression level in bursa of Fabricius was rose sharply; the HSP70mRNA expression in the thymus gland was dropped significantly at4h post-cold stress, and increased dramatically after3d of cold stress; and in the spleen HSP70mRNA expression did not change significantly. This suggests that cold stress have different influence on HSP70mRNA expression in different organs. Probiotics adding effectively reduced HSP70mRNA expression in the spleen and in bursa of Fabricius, these results show that probiotics treatment can improve royal chicks to resist to cold stress. Glucan adding rose sharply HSP70mRNA expression in bursa of Fabricius, it is obviously that glucan have different adjustment of HSP70mRNA expression in different organs.