| Holstein bulls are an important source of beef in our country.During the fattening process of holstein bulls,castration technology can promote fat deposition,improve beef tenderness,reduce aggression,and facilitate management.However,excessive deposition of adipose tissue in Holstein castrated cattle is likely to cause lipid metabolism disorders,resulting in changes in adipocytokine secretion patterns,and may lead to chronic inflammation of adipose tissue.Therefore,the study of fat metabolism and adipose tissue inflammation of holstein castrated cattle has important theoretical significance and practical value for scientific feeding and life health of fattening cattle.Three 12-month old Holstein fattening bulls(BF16),three 12-month old Holstein castrated bulls(SF16)and three 22-month old Holstein castrated bulls(SF26)were divided into 3 groups.They were fed for 4 months under the same feeding conditions and then slaughtered.Body weight was recorded at 30,60,90 and 120 days of the experiment period,and daily gain was calculated.Blood samples were collected before slaughter,and triglyceride(TG),cholesterol(TC),adiponectin(ADP),leptin(LEP)adipocytokines,interleukin 6(IL-6),Hypersensitive C-reactive protein(HS-CRP),and tumor necrosis factor-α(TNF-α)adipoinflammatory factors were detected by blood biochemistry and ELISA.After slaughter,omental adipose tissue was collected for HE staining sections to observe the morphology and size of adipose cells.RNA extraction and transcriptome sequencing were performed to select biological processes and signal pathways,and genes related to inflammation and immunity were screened for q PCR verification.To analyze the difference of adipose tissue metabolism and adipose tissue inflammation between fattening bulls and castrated bulls at the same age,and the difference of adipose tissue metabolism and adipose tissue inflammation between castrated bulls at different age.The results showed that the slaughter weight of BF16 was higher than that of SF16(P>0.05),and that of SF26 was significantly higher than that of SF16(P<0.01).The average daily gain of BF16 was higher than that of SF16(P>0.05),while that of SF26 was lower than that of SF16(P<0.01).The serum total cholesterol(TC)of BF16 was significantly decreased compared with THAT of SF16(P<0.05),and that of SF26 was decreased compared with that of SF16(P>0.05).Serum triglyceride(TG)of BF16 was significantly decreased compared with THAT of SF16(P<0.05),while that of SF26 was increased compared with that of SF16(P>0.05).ELISA results showed that IL-6 was significantly increased in SF16 compared with BF16(P<0.01),and in SF26 compared with SF16(P<0.01).Compared with BF16,TNF-α in SF16decreased(P>0.05),and TNF-α in SF26 increased significantly(P<0.01).Hs-crp was significantly increased in SF16 compared with BF16(P>0.05),and in SF26 compared with SF16(P<0.05).Compared with BF16,THE ADP of SF16 was significantly increased(P<0.01),the ADP of SF26 was significantly decreased(P<0.01),the LEP of SF16 was significantly increased(P>0.05),and the LEP of SF26 was significantly increased(P<0.01).The adipocytes were stained with HE,and the cell density and diameter were measured.The diameters of SF16 and SF26 cells were about 150 mm,while the diameters of BF16 cells were about 100 mm.The cell density of BF16 was significantly higher than that of SF16(P<0.01),but there was no significant difference between SF16 and SF26.RNA was extracted from adipose tissue of omentum for sequencing,and the sequencing results were verified.The 6 differentially selected genes were verified by q PCR.Ribosomal protein S14(RPS14)was the internal reference gene.The expression of myeloperoxidase(MPO),interleukin 6(IL-6),human galactolectin 3(LGALS3),7-acyl-coenzyme A(ACBD7),cx C-chemokine ligand 3(CXCL3)was up-regulated,while the expression of embryonic antigen 1(DLK1)was down-regulated.The expression trend was consistent with the transcriptome results.Finally,48 non-redundant differential genes significantly related to immunity and inflammation were screened by transcriptome sequencing.In conclusion,fat deposition and serum adiponectin concentration increased in holstein castrated cattle.With the prolongation of fattening time,the transcription levels of inflammatory genes and the concentration of inflammatory factors in serum increased significantly. |
