Effects Of Cold Stress On Lipid Energy Metabolism Pathway And Immune Function In Altay Lamb And Hybrids

Concent: Cold stimulation is detrimental to the health and welfare of animals,and further brings economic losses to the animal husbandry.The Altay region of Xinjiang has a severe winter and a long snow period,which brings great difficulties to sheep farming.Object: In order to explore the effects of cold stimulation on the lipid energy metabolism and immune function of Altay Lamb and Altay hybrid lambs.At the same time,the changes of cold resistance of hybrid lambs after the reduction of fat in the tail of it were compared,which provides a theoretical basis for sheep cold-resistant breeding.Carry out the following study:Methods: In this experiment,4 months old Altay and hybrid male lambs were selected as research objects,and selected-20? ~-10? and-30? ~-20? for the test conditions,lambs were stimulated coldly over time.Constructed a model of cold stress in lambs;lambs were sampled,and the distribution of TH was determined by immunohistochemistry;the content of hormone,IgG and Cortisol in serum was determined by ELISA,and the content of antioxidant factor was determined;Amplified the ADRB3,UCP1,and HSL genes and sequence them to analyze their homology with different species;the changes of transcription and translation levels of three genes in different tissues of lambs were determined by qPCR and Western Blot;HE staining and toluidine blue staining were used to observe the changes of microscopic structure of lamb small intestine and the changes of the number of goblet cells,epithelial lymphocytes and mast cells;qPCR was used to detect the expression of cytokine mRNA in peripheral blood leukocytes and spleen of lambs,and the immune function of lambs was observed.Results: 1.There are TH positive cells and fiber distribution in the cerebellum and hypothalamic paraventricular nucleus,and the positive expression increased after cold stress;The content of E by cold stress was upward trend;The NE content of Altay lambs first increased and then decreased,while the NE content of hybrid lambs continued to rise;The GC content of lambs was decreased first and then increased after weak cold stress,and then increased first and then decreased after strong cold stress;The INS content of Altay lambs first decreased and then increased,while the hybrid lambs were reversed;the LEP content of lambs decreased first and then increased.After cold stress,the SOD content in the serum of lambs was increased first and then decreased,and the MDA content was increased.2.The ADRB3,UCP1 and HSL genes have higher homology with the existed sheep sequences than 99%;The mRNA and protein expression of UCP1 and HSL in each tissue changed dynamically after cold stimulation,but compared with the normal temperature group was increased;The expression of ADRB3 mRNA in the interscapular fat was lower than that in the normal temperature group,and the expression level in the hypothalamus was different after strong and weak cold stimulation.3.After cold stress,the serum IgG content of lambs was lower than that of the normal temperature group,and the cortisol content was higher than that of the normal temperature group;Observing the microstructure of the small intestine of the lamb,the intensity of the small intestine was significantly shortened and thickened after long-term cold stimulation,and the number of goblet cells and mast cells in the small intestine increased,while the number of epithelial lymphocytes decreased.At the same time,the mRNA expression levels of IL-2,IL-4,IL-10,IL-12 and IFN-? in peripheral blood leukocytes and spleen were more variable in different time periods after cold stress,but the overall expression was higher than that in normal temperature group.Conclusions: In summary,with the increase of cold stimulation time and intensity,it will cause certain damage to the lamb;at the same time,the tail fat deposition of the lamb after hybridization will decrease,which may have an effect on the heat-producing ability,antioxidant capacity and immune function of lambs under cold stress,but it will not be lost.It indicates that the environment of Altay lamb is relatively stable,but after cold stress,it may still need to dynamically regulate the expression of related genes,constantly adjust energy metabolism,and adapt to temperature changes.The research results lay a certain theoretical foundation for the cold-resistant breeding of sheep in Xinjiang.