Objective To determine the reproductive physiology and blood physiological and biochemical characteristics of SPF Yorkshire and Landrace swine.Methods Ten reproductive physiology parameters,19 blood physiological parameters and 18 blood biochemical parameters in SPF Yorkshire and Landrace swine were measured using conventional methods and the differences between population,between age groups and between both sexes were analyzed.Results There were no significant differences(P>0.05) in reproductive physiology parameters and most blood physiological and biochemical parameters of the SPF Yorkshire and Landrace swine.A few of parameters,such as blood physiological indices GRAN,HGB,RDW,PLT,PCT,and blood biochemical indices ALKP,CHOL,TBIL,BUN,showed significant difference(P<0.05) between populations,between age groups and between both sexes,however,the values of difference were rather small,deviated from the normal range.Conclusion The physiological and biochemical characteristics of SPF Yorkshire and Landrace swine are basically stable and there is no significant difference compared with other laboratory miniature pigs.This study will provide valuable basic data for raising velvet yield,establishment of animal models and evaluating the genetic quality of closed colony.

Objective To understand the genetic background of the specific pathogen-free Yorkshire and Landrace pigs, imported from Canada by Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences.Methods The population genetics were investigated by using 19 pairs of microsatellite primers.Results In the Yorkshire pigs and Landrace pigs, 84 and 89 alleles, respectively, were detected at 19 microsatellites loci.The average polymorphic informa-tion content and mean heterozygosity in the Yorkshire pigs were 0.5271 and 0.5877, and in the Landrace population were 0.5652 and 0.6066, respectively.Because of the significant ( P<0.01) differences of alleles in different loci such as S0155,S0143,S0178,Sw857 and Sw936, it made them possible to be used to identify Yorkshire and Landrace pigs′breed. F-statistics showed that the differentiation within the population was small and genetic structure was stable.Conclusions Compare with the domestic pedigree large White and Landrace pigs, the SPF pedigree pigs imported from Canada are more stable in genetic structure, and can be used as laboratory animal models in animal science research.

Objective The aim of this study was to investigate the polymorphism of SLA class II genes in Canadian SPF Yorkshire and Landrace pigs.Methods Blood samples were obtained from 15 SPF Yorkshire and 22 Landrace pigs for isolation of peripheral blood mononuclear cells respectively, and the DQB1, DRB1 and DQA genes were amplified by PCR after reverse transcription.SLA class II genes were obtained by analyzing the direct and cloning result.The polymorphism of alleles was analyzed using the DNAsp 5.0 software.Results A total of 25 alleles were identified at three genes, including eight DQB1, ten DRB1 and seven DQA, and three alleles were submitted the complete sequences for the first time.The official allele names were assigned as SLA-DQB1*0212 (KU754590), SLA-DQB1*0203 (KU754591) and DRB1*06:07(KU754601) by the SLA Nomenclature Committee.Three novel DQA alleles were discovered.Five of the 15 amino acids, one of the 16 amino acids and 11 of the 19 amino acids, which bind processing antigens, showed well conserved among the alleles of DQB1, DRB1 and DQA genes in the SPF Yorkshire and Landrace pigs, respectively.Neighbor-joining tree showed that the three genes were divided into two clusters, respectively.There was a close relationship between SPF Yorkshire and Landrace pigs and foreign Yucatan miniature pigs, and it showed no obvious genetic distance with other pigs.Conclusions A total of 25 SLA class II alleles have been identified successfully in this study, and there are more abundant polymorphism for them.There is a widely distribution for SLA class II alleles identified in this study in other pig breeds.It is critical for the eventual future use of SPF Yorkshire and Landrace pigs as classical laboratory animal models.

Objective To investigate the influence of vitamin D deficiency on nonalcoholic steatohepatitis (NASH). Methods The patients with NASH who were hospitalized in Department of Infectious Diseases, The First Hospital of Changsha, from January 2020 to October 2021 were enrolled, and according to the serum level of 1, 25(OH) 2 D 3 , they were divided into group A with 1, 25(OH) 2 D 3 deficiency (< 20 ng/mL), group B with 1, 25(OH) 2 D 3 insufficiency (20-30 ng/mL), and group C with sufficient 1, 25(OH) 2 D 3 (> 30 ng/mL). The three groups were compared in terms of the serum levels of 1, 25(OH) 2 D 3 , alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBil), total cholesterol (TC), triglyceride (TG), interleukin-18 (IL-18), and interleukin-37 (IL-37) and liver pathological grade, and fibrosis-4 (FIB-4) index was calculated. A one-way analysis of variance was used for comparison of continuous data between multiple groups, and the least significant difference t -test was used for further comparison between two groups; the chi-square test was used for comparison of categorical data between groups. A Pearson correlation analysis was also performed. Results A total of 120 NASH patients were enrolled, with 40 patients in each group. Compared with group A, groups B and C had significant increases in the levels of 1, 25(OH) 2 D 3 and IL-37 and significant reductions in FIB-4 index and the levels of ALT, AST, TBil, TC, TG, and IL-18 (all P < 0.05). Compared with group B, group C had significant increases in the levels of 1, 25(OH) 2 D 3 and IL-37 and significant reductions in FIB-4 index and the levels of ALT, AST, TC, TG, and IL-18 (all P < 0.05). The correlation analysis showed that 1, 25(OH) 2 D 3 was negatively correlated with ALT ( r =-0.84, P < 0.001), AST ( r =-0.77, P < 0.001), TBil ( r =-0.32, P < 0.001), TC ( r =-0.45, P < 0.001), TG ( r =-0.42, P < 0.001), IL-18 ( r =-0.40, P < 0.001), and FIB-4 index ( r =-0.62, P < 0.001), and it was positively correlated with IL-37 ( r =0.59, P < 0.001). Compared with group A, groups B and C had significant reductions in the proportion of patients with severe steatosis ( χ 2 =51.46, P < 0.001), bridging fibrosis and early liver cirrhosis ( χ 2 =36.59, P < 0.001), or bridging necrosis and large-scale necrosis ( χ 2 =37.28, P < 0.001). Light microscopy showed that group A had extensive ballooning degeneration of hepatocytes, a large number of lipid droplets (mainly macrovesicular lipid droplets), disordered arrangement of the liver plate, lymphocyte infiltration, and focal bridging fibrosis; group B mainly had spotted focal necrosis, periportal fibrosis, lipid droplets with various sizes, a small amount of neutrophil infiltration, and ballooning degeneration of some hepatocytes; group C had ballooning degeneration of a small number of hepatocytes, focal perisinusoidal fibrosis, a small number of lesions with spotted focal necrosis, and a small number of lipid droplets in the cytoplasm of hepatocytes. Conclusion The degree of liver injury and fibrosis increases with the reduction in vitamin D level, and vitamin D measurement helps to evaluate the progression of NASH.

Intestinal microbiota plays an important role in maintaining liver metabolic homeostasis and affects the development and progression of hepatocellular carcinoma by participating in bile acid metabolism. Gut-liver axis plays an important role in the pathogenesis of liver diseases， and it might be one of the effective methods to prevent the progression of hepatocellular carcinoma by correcting intestinal ecological imbalance to restore normal bile acid level. This article summarizes the mechanism of bile acid receptor affecting hepatocellular carcinoma and the latest therapeutic targets， in order to provide a reference for the early prevention and treatment of hepatocellular carcinoma.