| Erhualian and Shawutou pig are excellent local varieties in China.Yorkshire is the largest populated purebred pig breeds.Landrace-Yorkshire hybrid(LY)pig is the largest populated commodity production sows.In order to investigate the effect of different locations in variety of sows on daily gain,diarrhea rate of piglets and colostrum protein,to preliminarily explore protein gene expression related influencing factors.A total of 15 Erhualian sows(Erhualian preservation farm in Changshu),19 Shawutou and 9 LY sows(Jiangsu Agriculture and Animal husbandry science and Technology Development Co.,Ltd.),9 LY and 6 Yorkshire sows(Haimen Pengxiang ecological agriculture park)and their piglets were selected.The experimental sows were fed ad libitum but given twice daily and watered freely.The study is composed of the following three parts:Experiment 1:Effects of sow breeds and suckling location on early daily gain and diarrhea rate of pigletsErhualian,Shawutou and LY sows,piglets were weighed and numbered on ear.Totaling 585 pigletswere included in the experiment.Weight of the piglets was weighed every two days until the 9th day of age,suckling locationof the pigletswas observed and recorded one by one.Erhualian piglets were weighed after born and once every two days until the 21st day.Results showed that the number of nipples in different breeds was significantly different,decreased from Erhualian,Shawutou to LY(P<0.001).The correlation between the number of nipples and the daily gain of piglets was not significant.There was a significant correlation between daily gain and birth weight(R = 0.640,P<0.001).There was no significant difference on the daily gain of Erhualian or Shawutou piglets suckled different mammary location.There was a significant difference on weight gain of LY piglets suckled in different mammary locations(P = 0.038)and the daily gain of the anterior piglets was higher than that of the middle and posterior piglets.In this study,Erhualian pigs were used as experimental animals to observe the diarrhea situation of piglets,as well as the differences of piglets in different sucklinglocations.Results showed that there was no significant difference in birth weight between healthy piglets and diarrhea piglets,but there was a significant difference in body weight on day 21 between them(P = 0.011).There was no significant difference in diarrhea rate and diarrhea frequency amongsucklinglocations.Diarrhea rate of piglets gradually increased before day 12,reached the highest on day 12(20.94%),and decreased gradually after day 12.It was suggested that the incidence of diarrhea was not correlated with the sucklinglocations,the occurrence of piglet diarrhea has a phased feature.Experiment 2:Analysis of concentration of 8 proteins in colostrum among different mammary areas in different sow breedsAfter the first piglet was born,20 mL of colostrum was collected from anterior,middle,posterior mammary gland in 2 hours.Centrifuge to remove fat and casein and the levels of ALB,PIGR,Ig M,Ig A,Ig G,Lectin,HP,λ-Ig LC in colostrum were analyzed by ELISA.Results showed that there was no difference among anterior,middle and posterior in fourvarieties about concentration of the 8 proteins.However,HP and PIGR showed a significant difference(P = 0.047,P = 0.036)between Shawutouand LY sows from the same farm,and λ-IgLC showed a highly significant difference(P = 0.004)between Shawutou and LY sows from the same farm.In addition,there were significant differences on concentration ofthe 8 colostrum proteins of LYs between the two different farms.Results showed that the location of mammary area had no effect on the above 8 proteins concentration in colostrum,but the variety and farm had a significant influence on some colostrum protein indexes.Experiment 3:Analysis of gene structure variation mechanism in different concentration of colostrum protein in different breedsThe results of Experiment 2 showed that there were differences in concentrations of PIGR,HP and λ-Ig LC in the colostrum between Shawutou and LY sows from the same farm,suggesting that the difference may be due to the mutation of the relevant protein coding gene,leading to transcription and protein level expression difference.In this study,we investigated the gene structure of PIGR and HP differential proteins.Fifteen Shawutou and 12 LY pregnancy sows with asimilar expected date of confinement were selected from the same farm,the DNA was extracted.The primers were designed according to the PIGR and HP gene sequences.The 5’ UTR and 3’ UTR region,and sequenced.Seventeen SNP loci were found,where the Fst values of the three SNPs were greater than 0.5,including 73897277 and 73897544 of the PIGR-3’ UTR(the two mutations were completely linked)and the HP2-5’ UTR02 14645066,indicating that these SNPs have been significantly differentiated between Shawutou and LY sows.By estimating the binding efficiency of SNP and miRNA,it was found that the different genotypes of these three SNPs could affect the binding efficiency of two genes and multiple miRNAs,leading to differences in gene transcription and protein expression.In conclusion,there was no differences on early growth performance of piglets among different suckling locations of Chinese Erhualian and Shawutou sows,but there was a difference among different suckling locations of LY piglets.There was no difference in diarrhea rate of Erhualian piglets among different suckling locations.There was no difference of the concentration of 8 proteins in colostrum among mammary glands of sows,but there were differences among species as well as between different farms.There were three SNPs with different allele frequencies in the 5’ UTR and 3’ UTR regions of the PIGR and HP gene promoters,and the different genotypes of the three SNPs could affect the binding efficiency of PIGR and HP genes with multiple miRNAs. |
