The Effects Of Endotoxin On Immune Activation And The Synthesis Of Milk Fat And Milk Protein And Their Control In The Mammary Tissue Of Dairy Cows

This test is designed to study the impact of endotoxin on immune status, lactation performance and their control in dairy mammary tissue. In vitro tests 1, the main objective was to study the effect of LPS on mammary tissue, the synthesis of milk fat,casein and cytokines (IL-1β, IL-6, IL-8) and tumor necrosis factor-α (TNF-α), the expression of milk fat and milk protein synthesis-related genes and cytokines (IL-1β, IL-6, IL-8,TNF-α) and signaling pathway(PPARy, TLR4, NF-κBp65).In vitro tests 2, the main objective was to study the effect of vitamin E, ethyl pyruvate and glutamine on the synthesis of milk fat,casein and cytokines (IL-1β, IL-6, IL-8) and tumor necrosis factor -α (TNF-α), the expression of milk fat and milk protein synthesis-related genes and cytokines (IL-1β,IL-6, IL-8, TNF-α) and signaling pathway (PPARy,TLR4,NF-κBp65), to provide experimental basis to reduce the impact of endotoxin on lactation performance.Experiment 1:The test is divided into 5 treatment (0 ng/mL; 1 ng/mL; 10 ng/mL; 100 ng/mL:1000 ng/mL). Holstein cow mammary tissue is blocked as a model within these medium separately cultivated at 72 h to evaluate the effect of LPS on mammary tissues. It contains casein, triglycerides, cytokines (IL-1β, IL-6, IL-8) and tumor necrosis factor-a (TNF-a) synthesis; Toll-like receptors, nuclear factor-κBp65 (NF-κBp65), cytokines (IL-1β, IL-6, IL-8 and TNF-α), PPARy and milk protein and milk fat synthase gene expression of mRNA; the threshold of endotoxin which causes immune activation and decreases the synthesis of milk fat and milk protein in mammary tissue. Bovine mammary tissue were incubated in the growth medium with 0, 1,10,100,1000 ng/mL at 72 h, collected the bovine mammary tissue and measured related indicators. The results showed that:(1)1 ng/mL LPS can extremely significantly increase gene expression of TNF-α (P<0.01), significantly increase gene expression of IL-6 (P<0.05), extremely significantly reduce gene expression of ACACA, FACS, ACSL1, CSN1S1, CSN2 (P<0.01), but had no effect on TLR4, NF-κBp65, IL-1β,IL-8, PPARγ and CSN3 genes expression level. (2) 10 ng/mL LPS can significantly increase the gene expression of NF-κBp65 (P<0.05), extremely significantly increase gene expression of TNF-α, IL-6 and IL-8 (P<0.01); has a trendency to increase the gene expression of IL-1β (P>0.05); extremely significantly reduce the gene expression of milk fat (ACACA, FASN, ACSL3) and milk protein (CSN1S1, CSN2) (P<0.01), significantly reduce the gene expression of CSN3 (P<0.05) but had no effect on TLR4 and PPARy genes expression level. (3)10,100,1000 ng/mL LPS had no significant difference on the gene expression of TLR4, PPARr, NF-κBp65, TNF-α, IL-6, IL-8, IL-1β,ACACA, FASN, ACSL3,CSN1S1, CSN2 and CSN3 (P>0.05). (4) 1 ng/mL LPS can significantly increase the synthesis of IL-1β (P<0.05), had a tendency to increase the synthesis of IL-6, IL-8 and TNF-α; the synthesis of triglyceride and casein trend to be lower (P>0.05). (5) 10 ng/mL LPS can extremely significantly increase the synthesis of IL-1β, IL-6 and TNF-α (P<0.01); significantly increased the synthesis of IL-8 (P<0.05); the synthesis of triglycerides tends to decreased (P>0.05); extremely significantly decrease the synthesis of casein (P<0.01). (6) 10,100,1000 ng/mL LPS had no significant difference on the synthesis of IL-1β, IL-6, TNF-α, IL-8,triglycerides and casein (P>0.05).Experiment 2:The test is divided into 4 treatment (10 ng/mL of LPS; 10 ng/mL of LPS+4 IU of vitamin E; 10 ng/mL of LPS+1 mmol/L of ethyl pyruvate; 10 ng/mL of LPS+1 mmol/L glutamine). Holstein cow mammary tissue is blocked as a model within these medium separately cultivated at 72 h to detect the synthesis of casein, triglycerides, cytokine (IL-1β, IL-6, IL-8) and tumor necrosis factor-a (TNF-α) and the gene mRNA expression of TLR4, NF-κBp65, cytokines (IL-1β, IL-6, IL-8 and TNF-α), PPARγ and the synthase gene mRNA expression of casein and fat, and compare the effects of these three substances. These results showed that:(1) vitamin E significantly reduced the mRNA gene expression of NF-κBp65, IL-1β, IL-8 (P<0.05) and had a tendency to decrease the synthase gene mRNA expression of IL-6 (P>0.05), but had no effect on TNF-α, TLR4 and PPARγ genes expression level (P>0.05); glutamine significantly reduces the mRNA gene expression of TLR4, IL-8 (P<0.05), but had no effect on TNF-α, NF-κBp65, IL-1β, IL-6 and PPARγ genes expression level (P>0.05); ethyl pyruvate significantly reduced the mRNAγ gene expression of IL-1β, IL-8 (P<0.05), but the effect is not as good as vitamin E, and had no effect on TNF-α, NF-κBp65, TLR4, IL-6 and PPARγ genes expression level (P>0.05). (2) Vitamin E significantly increased the mRNA gene expression of ACACA (P<0.05), but had no effect on milk fat synthesis-related genes FASN and ACSL3 genes expression level (P>0.05); glutamine significantly increased the mRNA gene expression of FASN (P<0.05), but had no effect on milk fat synthesis-related genes ACACA and ACSL3 genes expression level (P>0.05); ethyl pyruvate extremely significantly improved the mRNA gene expression of ACSL3 (P<0.01), the mRNA gene expression of ACACA and FASN tends to be increased (P>0.05). (3) Vitamin E extremely significantly increased the mRNA gene expression of milk proteins in breast tissue CSN1S1, CSN2, CSN3 (P<0.01); glutamine and pyruvate extremely significantly improves the gene expression of the CSN2, CSN3 (P<0.01) but had no effect on casein related genes CSN1 gene expression level (P>0.05). (4) vitamin E tends to decrease the synthesis of IL-1β (P>0.05), significantly decreased the synthesis of IL-6 (P<0.05), extremely significantly reduce the synthesis of IL-8 (P<0.01), and extremely significantly increased the synthesis of casein (P<0.01), had no effect on milk fat, IL-1β and TNF-α synthesis (P>0.05); glutamine extremely significantly reduced synthesis of IL-8 (P<0.01), extremely significantly increased synthesis of casein (P<0.01), had no effect on milk fat, IL-1β,IL-6 and TNF-α synthesis (P>0.05); ethyl pyruvate tends to reduced the synthesis of IL-1β and TNF-α (P>0.05), extremely significantly increased the synthesis of triglyceride (P<0.01), tends to improve the synthesis of casein (P>0.05), but had no effect on the synthesis of IL-6 and IL-8 (P>0.05).