| The expreriment of this thesis was conducted to study the effects of conjugated linoleic acids(CLA)on meat quality and related gene expression in Rongchang pigs.In addition,the effects of CLA on the expression of miRNAs in skeletal muscle were analyzed by high throughput sequencing.These results would provide an theoretical and experimental basis for the wide application of CLA in animal production.A total of 50 healthy Rongchang piglets with similar body weight,were randomly allocatedto control group and CLA group.Each group consisted of 5 replicates with 5 piglets per replicate(There was no significant difference between groups).The weaned piglets of CLA group were fed the diet with 1.5% CLA,which equivalent to replace soybean oil.The nutrition level of diets were same between two groups.When the average weight of pigs reached about 85 kg,each pig was randomly selected from each replicates to weigh and slaughter.Carcass traits and meat qualities were assessed after slaughter.Then,the longissimus dorsi muscles were collected for the determination of the expressions of genes related to meat quality and miRNAs high throughput sequencing.The results were as follows: 1.Effects of dietary CLA on meat quality and expression of related gene in Rongchang pigs(1)Compared with the control group,dietary CLA reduced the mean fat thickness by 7.55%;increased intramuscular fat content by 24.71%(P<0.1);increased pork color score by 9.3%(P<0.1);decreased pork color b values by 22.7%(P<0.05);increased density of muscle fiber by 23.47%;increased T-AOC activity in muscle(P<0.05);decreased MDA content in muscle(P<0.01).(2)Compared with the control group,the expressions of PPARγ,PGC-1α,FABP4 and FAS were significantly increased(P<0.05)in CLA group,the expression of C/EBPα and FATP1 were significantly increased(P<0.01);the expression of MyHC1 was significantly increased(P<0.05),the expression of MyHC2 a was significantly increased(P<0.01).2.Effects of dietary CLA on muscle miRNAs of Rongchang pigs(1)First,small RNA libraries of control group and CLA group was constructed.Then,libraries were sequenced by Solexa,and screened by database to get clean reads.In addition,compared clean reads to the mi RBase21.0 database and the swine genome database.A total of 556 miRNAs were identified in two libraries,which 472 miRNAs were co-expressed.Compared with the control group,the expression of 96 miRNAs were significantly down-regulated in the CLA group(P<0.01),and the expression of 156 miRNAs was significantly up-regulated in the CLA group(P<0.01).(2)Compared with the control group,the 13 miRNAs was up-regulated more than 1.5 times or was down regulated less than 0.6 times,copy number was more than 500,the expression was significantly changed by CLA(P<0.01).7 miRNAs(miR-1,miR-206,miR-335,miR-486,miR-133 b,miR-186,miR-374a-3p)involved in muscle growth and development,3 miRNAs(miR-30 e,miR-21,miR-199a-5p)involved in fat metabolism,3 miRNAs(miR-19 b,miR-127,miR-7)related to the occurrence and development of cancer in 13 miRNAs.(3)A total of 2815 target genes were predicted for 10 mi RNAs which involved in muscle growth,development and fat metabolism.target genes mainly enriched in the pathways of metabolic(P<0.01)and AMPK signaling and so on(P<0.01).PPARγ,PGC-1α and FAS were in the downstream of AMPK signaling pathway,that pointed out CLA might act on the AMPK signaling pathways,regulate of downstream fat metabolism genes vis mi RNAs,thereby affecting muscle fat metabolism and meat quality traits in pigsIn summary,dietary supplementation of appropriate CLA could improve pork quality and significantly change the expression of genes related to meat quality and muscle mi RNAs,but the detailed mechanism of CLA improved pork quality through miRNAs,that still needs further study. |
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