| Cold stress is an important factor restricting the development of animal husbandry.In modern breeding,it is essential to enhance the resistance and heat production capacity of animals besides cold prevention measures.The organism consumes energy to maintain body temperature,and brown fat is the main site of heat production.In the mechanism of brown fat thermogenesis,adrenaline stimulation is a key thermogenesis pathway.Tyrosine is a precursor of catecholamines.Studies have shown that oral tyrosine can supplement catecholamines in the body and protect the body from immune decline caused by excessive consumption of adrenaline in cold environment.The phenomenon of white fat browning is the body’s response to protect itself under cold stress,and the beige fat has the same heat-producing function as brown fat.Formononetin has been shown to affect the Browning of white fat by modulating PPARγ.However,the effect of the addition of tyrosine in combination with the Chinese herbal monomer,formononetin,on lipid metabolism is still unclear,and there are few relevant studies.Therefore,to further understand whether amino acids combined with Monomer of Traditional Chinese medicine can also promote heat production,and to understand the effects of amino acids combined with formononetin on lipid metabolism in the body under normal temperature and cold stress conditions respectively,providing new ideas for improving cold resistance of the body.In order to understand the effects of tyrosine combined with cysteine and formononetin on lipid metabolism in mice,we conducted a two-stage experiment.In the first stage,to understand the effects of tyrosine combined with cysteine on lipid metabolism in mice,we selected3-week-old male C57BL/6J mice as experimental subjects.They were randomly divided into 8groups with 6 rats in each group,including control group and 1%,3% and 5% tyrosine combined cysteine groups,respectively,under room temperature and 4 cold environment.In ℃order to understand the effects of tyrosine combined with cysteine and formononetin on lipid metabolism in mice,3-week-old male C57BL/6J mice were randomly divided into 6 groups with 6 mice in each group at room temperature and 4℃.The three groups were control group and formononetin group at 8mg/kg/d and 16mg/kg/d,respectively.Different concentrations of tyrosine combined with cysteine were fed for 28 days.After feeding,the animals in each group grew well,and the body weight of the mice was weighed every 7 days.After feeding for 28 days,blood was collected,and serum was separated.Four biochemical indexes in serum of mice in each experimental group were detected by enzyme colorimetry.Morphological changes of fat were observed by HE staining.Western Blot was used to detect the expression of p38,P-P38,PRDM16,PGC1α,PPARα,PPARγ and UCP1 in brown fat differentiation and lipid metabolism related signaling pathways.Immunohistochemical method was used to detect the expression of UCP1 and PGC1α proteins.The results showed that compared with the control group,the body weight of 3% tyrosine and cysteine mice increased significantly at room temperature,and the contents of TG,TC,HDL-C and LDL-C in blood biochemical indexes increased.HE staining results showed that lipid droplets became larger,and the expression of UCP1 and PGC1α in shoulder scapula,epididymitis and subcutaneous decreased.On the contrary,the body weight gain of cold exposure mice with tyrosine and cysteine supplementation was significantly reduced compared with the control group,and the contents of TG,TC,HDL-C and LDL-C in blood biochemical indexes were decreased.HE staining results showed that lipid droplets became smaller,and the expression of UCP1 and PGC1α in shoulder scapula,epididymites and subcutis were increased.Immunohistochemical results showed that UCP1 and PGC1α proteins were significantly upregulated by cold exposure in subcutaneous fat of 3% tyrosine combined with cysteine.Formononetin at different concentrations was administered intragastric for 28 days.After intragastric administration,the animals in each group grew well,and the body weight of the mice was weighed every 7 days.After feeding for 28 days,blood was collected and serum was separated.Four biochemical indexes in serum of mice in each experimental group were detected by enzyme colorimetry.Morphological changes of fat were observed by HE staining.Western blotting was used to detect the expression of brown fat differentiation and lipid metabolism-related nuclear transcription proteins P38,P-P38,PRDM16,PGC1α,PPARα,PPARγ,UCP1.The results showed that there was no significant difference in body weight gain in the group of tyrosine and cysteine combined with 8mg/kg/d formononetin compared with the control group at room temperature,and the contents of TG,TC,HDL-C and LDL-C in blood biochemical indexes increased.HE staining showed that lipid drops decreased,and the expression of UCP1 and PGC1α in shoulder scapula,epididymis and subcutis increased.Compared with the control group,the cold exposure group supplemented with tyrosine,cysteine and 8mg/kg/d of formononetin significantly increased body weight,decreased the contents of TG,TC,HDL-C and LDL-C in blood biochemical indexes,and HE staining results showed that lipid drops became smaller,and the expression of UCP1 and PGC1α in shoulder scapula,epididymis and subcutis increased.These results indicate that when amino acids are added to diets at room temperature,tyrosine is mainly involved in the synthesis of sugars,proteins,fats and other nutrients in the body through protein metabolism,thus resulting in weight gain.When cold stress occurs,tyrosine focuses on the synthesis of catecholamines and promotes catabolism in the body.The PPARγ signaling pathway of thyroxine regulates the synthesis of UCP1,promotes fat Browning,and consumes stored TG to enhance thermogenesis.Tyrosine and cysteine combined with formononetin promotes the expression of PPARγ and browns the white fat in the epididymis and subcutaneous to strengthen fat metabolism and promote lipid decomposition. |
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