The Developmental Patterns of Somatostatin Gene Expression in Gastric Tissue of Erhualian and Large White Pigs

In present study, the developmental patterns of somatostatin (SS) gene expression in gastric tissue were compared between Erhualian and Large White pigs. A semi-quantitative RT-PCR was applied to determine the levels of SS mRNA. The results indicated that: (1) The gastric SS mRNA expression was high at birth, followed by a significant decrease (P<0. 05) at 3 days of age in both breeds of pigs; (2) From 3 to 30 days of age, the expression of SS mRNA in gastric tissue exhibited remarkable up-regulation in both breeds, after which a strain difference in the developmental pattern was observed. In Erhualian pigs, SS mRNA expression reached a peak at 90 days of age, declined thereafter towards 180 days of age. In Large White pigs, however, the expression of SS mRNA remained constant from 30 days of age onwards; (3) In general, Erhualian pigs expressed higher levels of SS mRNA in gastric tissue compared with Large White pigs at the same age. The strain difference was significant from birth to 90 days of age, but vanished at 120 and 180 days of age. The results suggest that the gastric expression of SS in the pig is regulated following an instinct timetable in a strain-specific manner, its relationship with the development of gastric function as well as its interactions with environmental factors are to be elucidated.

Association of polymorphisms of Nramp1 gene with immune function and production performance of large white pig

The present research was designed to study the association of polymorphism of natural resistance-associated macrophage proteinl （Nrampl） with some immune function and the production performance in Large White pig. The PCR-RFLP technique was applied to analyze the correlation between the polymorphisms of Nrampl gene and immune function [value of Polymorphonuclear Leukocytes （PMN） obtained by Nitroblue Tetrazolium （NBT） Reduction and effect of Cytotoxin in Monocyte] and production performance in 165 Large White pigs. The results showed that there was one Nde I restriction locus in Large White pig, and both values of PMN by NBT Reduction and effect of Cytotoxin in Monocyte in genotype BB were higher than those in genotype AB （P〈0.05）. Simultaneously, the weight of 180-day-old pigs with genotype BB was higher than that with genotype AB （P〈0.05）. The results indicated that there was a significant correlation between different genotypes of Nrampl gene and Immune function and production performance, and it can be regarded as a candidate gene of disease resistance. All these results provide valuable reference to further studies of pig disease resistance.

Cloning,Expression and Functional Analysis of Osteopontin Gene in Large White Pig

The full-length cDNA of 909 bp of the osteopontin gene(OPN) was isolated from of Large White Pig and analyzed with bioinformatics methods.The results showed high proportions of Asp,Glu and Ser and verified presence of the special sequence Arg-Gly-Asp(RGD) in the primary structure of OPN.There were high proportions of alpha helices and strong hydrophilicity in the secondary structure. The signature sequence of OPN([KQ]-x-[TA]-x(2)-[GA]-S-S-E-E-K) was located in the first region of high homology.Two phylogenetic trees were constructed,based on the entire OPN protein sequence and the conserved signature sequence,and showed that the relationship between pig and cow was the closest, but farthest between pig and chicken.OPN mRNA was expressed in many tissues of the pig:higher in the stomach,kidney,lung,small intestine and ovary,and lower in the heart,spleen and large intestine.The OPN protein size differed in different tissues:70 kDa in liver and muscle,70 and 45 kDa in stomach,small intestines and kidney,70,45 and 24 kDa in lung,heart and uterus.

Higher Tolerance of Min Pigs Under Cold Stress:An Assessment from Reproduction Perspective

Raising Min pigs(MPs)in northern China is challenging,because of harsh environmental conditions in winter.There is a hypothesis that MPs can tolerate cold stress better than Large White pigs(LWPs)and their oocyte competence is particularly protected.Over a period of 3 years,multiple cohorts of MPs and LWPs under different environmental conditions were studied in this paper.Follistatin(FST)serum level was used as a marker for swine oocyte competence.Oocytes were collected from the swine and their maturation rate,cleavage rate and blastocyst rate were measured.Lastly,mRNA expression in ovary and longissimus dorsi for the genes FST,luteinizing hormone receptor(LHR)and cold-inducible RNA-binding protein(CIRP)was measured.Under cold stress,serum follistatin concentrations of both LWPs and MPs were markedly increased,and they were more in LWPs than in MPs.However,oocyte competence was found to be unaffected by cold stress in MPs.It was found that in a separate group of LWPs,oocyte competence was lower in samples collected in winter than that in other seasons.Interestingly,follistatin levels in the follicular fluid of MPs showed no change with cold stress,and serum follistatin levels were increased in sows.Gene expression analysis showed a significant reduction in FST,LHR and CIRP expressions under cold stress in longissimus dorsi,but not in the ovaries.It was found that MPs were better able to maintain oocyte competence under cold stress,which might be due to improved regulation of follistatin in follicular fluid,and MPs appeared likely an adaptation to the harsh conditions that they faced under domestication in northern China.