| Lower temperature environment has an important impact on the health of animals in the northern alpine and cold regions.Taurine,as a food additive,has the functions of antioxidation,immune regulation,detoxification,osmotic regulation and nerve regulation.It not only enhances the index of immune organs,but also enhances the activity of lymphocyte and promotes its proliferation,at the same time,it has no side effects on animal body.In this experiment,the effect of taurine on the immune function of broilers under lower temperature environment was studied.240 AA broilers were randomly divided into three groups at the age of 14 days: control group(22-24 ?),lower temperature group(8-11 ?,1-2 ? every day from 14 days,stable at 11 ? until 21 days),taurine lower temperature group(8-11 ?,1% taurine added to drinking water),each group of broilers free to eat and drink water.At the beginning of 7 days,14 days,21 days and 28 days under lower temperature,the body was weighed.Collect venous blood to separate plasma and serum,detection of serum total protein content by BCA microplate method;detection of serum albumin content by microplate method;detection of lysozyme content by turbidimetry;determination of acid phosphatase by enzyme labeling;detection of Ig G and Ig M in plasma by ELISA;extraction of 28 days peripheral white blood cells' s RNA from anticoagulant;preparation of blood smears for leucocyte count;spleen,thymus and bursa of fabricius were separated and weighed,stored at-80 ?;extraction of spleen,thymus and bursa of fabricius tissues for 14 days and 28 days,The expression of IL-2,IFN-?,IL-4,IL-6,IL-10,IL-12? and IL-12? m RNA in spleen,thymus,bursa of fabricius and peripheral white blood cells was determined by q RT-PCR.The results are as follows:1.Compared with the control group,under the lower temperature's broiler,the spleen index at 21 days and 28 days,the thymus index at 7 days,14 days,28 days,the bursa of fabricius index at 21 days,were decreased significantly(P < 0.01),spleen index was significantly increase at 7 days under lower temperature(P < 0.01).At 7 days,the spleen index of broilers was decreased significantly after adding taurine under lower temperature(P < 0.01)and the bursa index of broilers were increased significantly after adding taurine at 28 days under lower temperature(P < 0.01).2.Under the lower temperature,the total serum protein of broilers was increased significantly at 28 days(P < 0.01),with the increase of age,the total serum protein of broilers were increased at 7 days and 21 days(P < 0.05)and was increased significantly at 28 days(P < 0.01).The total protein content was increased significantly at 28 days(P < 0.05)and albumin was increased significantly at 21 days and 28 days after adding tuarine(P < 0.05,P < 0.01).3.Under lower temperature,the plasma Ig G of content were increased at 21 days and 28 days(P < 0.01)and Ig M content was decreased(P > 0.01)at 14 days.The serum Ig G content was decreased significantly(P < 0.01)and Ig M was increased significantly(P < 0.01)after adding taurine at 21 days under lower temperature.4.Under lower temperature,acid phosphatase activity in blood were increased at 7days and 14 days(P < 0.05),and lysozyme activity were decreased at 14 days and 28 days(P < 0.01).The addition of taurine decreased the activity of acid phosphatase in the blood at 7days and 14days(P < 0.01,P < 0.05),and increased the activity of lysozyme at 7days and 14days(P < 0.01).5.At 14 days under lower temperature in spleen,compared with the control group that the expression of IL-2 was extremely significant decreased(P<0.01),the expression of IL-12? and IL-12? were significant increased(P<0.01,P<0.05).The expression of IL-6 and IL-12? were significant decreased(P<0.05,P<0.01)in spleen and expression of IFN-? and IL-10 were significant increased(P<0.01,P<0.05)after adding taurine under lower temperature.At 28 days under lower temperature,compared with the control group,the expression of IFN-? and IL-10 were extremely significant decreased(P < 0.01),but there was no significant difference in the addition of taurine(P > 0.05).6.At 14 days under lower temperature in bursa of fabricius,the expression of IFN-?,IL-12? and IL-12? were decreased significantly(P < 0.01,P < 0.01,P < 0.05);the expression of IL-4 and IL-10 in bursa of fabricius of broilers were extremely significant decreased(P < 0.01)while adding taurine under lower temperature.At 28 days under lower temperature in bursa of aabricius,the expression of IL-2,IFN-?,IL-4,IL-6,IL-10,IL-12? and IL-12? m RNA were extremely significant decreased(P < 0.01),but there was no significant difference between the taurine group and low temperature group(P > 0.05).7.At 14 days under lower temperature in thymus,the expression levels of IL-2,IFN-?,IL-6,IL-10 and IL-12? were extremely significant increased(P < 0.01);the expression of IL-4 was extremely significant increased(P < 0.01)and IL-10 was extremely significant decreased(P < 0.01)after taurine treatment.At 28 days under lower temperature,the expression of IL-2,IL-6 and IL-12? m RNA were significant increased(P < 0.05),IL-12? m RNA was extremely significant increased(P < 0.01),IFN-? and IL-10 m RNA were extremely significant decreased(P < 0.01);taurine had no significant effect on the expression of the above genes(P > 0.05).8.At 28 days under lower temperature,the expression of IFN-? m RNA in peripheral white blood cells was significant decreased(P < 0.05),the expressions of IL-12? and IL-10 m RNA were extremely significant decreased(P < 0.01),the expression of IL-4 and IL-6 m RNA was extremely significantly increased(P < 0.01);After adding taurine,the expression of IL-12? m RNA in peripheral blood leukocytes was extremely significant increased(P < 0.01),the expression of IL-4 m RNA was significant decreased(P < 0.05),the expression of IL-6 m RNA was extremely significant decreased(P < 0.01).9.At 7 days under lower temperature,the proliferation of the ratio of atypical cells to lymphocytes was promoted(P < 0.01),and the proliferation of the ratio of atypical cells to lymphocytes was inhibited by adding taurine.In conclusion,taurine can maintain spleen index under lower temperature at 7 days,increase bursa index of broilers at 28 days under lower temperature,promoting the growth and development of bursa of fabricius is helpful to improve the immunity of broilers;Increase the levels of 28 days total protein,21 days and 28 days albumin in the body's blood to increase protein synthesis to maintain self-growth requirements under lower temperature;Inhibiting the elevation of 21 days Ig G and promoting the elevation of 21 days Ig M to improve the body's immunity,Inhibition of acid phosphatase activity for 7 days and 14 days resulted in normal phagocytic activity of macrophages,increasing lysozyme activity for 7 days and 14 days enhances nonspecific immunity;At 14 days under lower temperature,the expression of anti-inflammatory cytokine(IL-10)in spleen was increased,so that inhibiting the production of pro-inflammatory cytokines(IL-12?),expression of anti-inflammatory cytokine(IL-10)in bursa of fabricius and thymus was decreased;At 28 days,the expression of IL-12? in peripheral blood leukocytes was increased and the expression of IL-4 and IL-6 were decreased,it enhances the cellular immunity level and inhibits the humoral immunity level;the ratio of heterophil cells to lymphocyte proliferated after 7 days was reduced,which was close to the level of control group.Thus,the immune function of broilers under lower temperature environment was enhanced. |
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