Korean Native Pig (KNP) has a uniform black coat color, excellent meat quality, white colored fat, solid fat structure and good marbling. However, its growth performance is low, while the western origin Yorkshire pig has high growth performance. To take advantage of the unique performance of the two pig breeds, we raised crossbreeds (KNP × Yorkshire to make use of the heterotic effect. We then analyzed the liver transcriptome as it plays an important role in fat metabolism. We sampled at two stages: 10 weeks and at 26 weeks. The stages were chosen to correspond to the change in feeding system. A total of 16 pigs (8 from each stage) were sampled and RNA sequencing was performed. The reads were mapped to the reference genome and differential expression analysis was performed with edgeR package. A total of 324 genes were found to be significantly differentially expressed (|log2FC| > 1 & q < 0.01), out of which 180 genes were up-regulated and 144 genes were down-regulated. Principal Component Analysis (PCA) showed that the samples clustered according to stages. Functional annotation of significant DEGs (differentially expressed genes) showed that GO terms such as DNA replication, cell division, protein phosphorylation, regulation of signal transduction by p53 class mediator, ribosome, focal adhesion, DNA helicase activity, protein kinase activity etc. were enriched. KEGG pathway analysis showed that the DEGs functioned in cell cycle, Ras signaling pathway, p53 signaling pathway, MAPK signaling pathway etc. Twenty-nine transcripts were also part of the DEGs, these were predominantly Cys2His2-like fold group (C2H2) family of zinc fingers. A protein-protein interaction (PPI) network analysis showed that there were three highly interconnected clusters, suggesting an enrichment of genes with similar biological function. This study presents the first report of liver tissue specific gene regulation in a cross-bred Korean pig.

본 연구는 교잡돈의 출하일령은 약 200일 이고, 175두의 돼지를 도축하여 3개의 그룹(59 ~ 95kg, 96 ~ 110kg, 111 ~ 148kg)으로 나누어, 등심, 상완세갈래근, 대퇴두갈래근, 반막모양근의 육질 특성을 조사하였다. 콜라겐과 지방함량은 반막모양근, 대퇴두갈래근이 111 ~ 148kg 그룹에서 다름 그룹에 비 해 낮은 함량을 나타내었으며(p<0.05), 단백질함량은 반막모양근, 대퇴두갈래근과 상완세갈래근이 111 ~ 148kg 그룹에서 다른 그룹에 비해 높은 함량을 나타내었다(p<0.05). 등심과 반막모양근의 명도는 111 ~ 148kg 그룹에서 높게 나타내었으며(p<0.05), 적색도와 황색도는 유의적인 차이가 나타나지 않았 다(p>0.05). pH는 등심에서 체중이 증가함에 따라 낮은 값을 나타냈었다(p<0.05). 가열감량은 등심, 반 막모양근, 대퇴두갈래근, 상완세갈래근이 111 ~ 148kg 그룹에서 보다 59 ~ 95kg 그룹에서 낮게 나타 났으며(p<0.05), 보수력은 반막모양근과 대퇴두갈래근에서 체중이 증가할수록 높게 나타났다(p<0.05). 전단력은 등심과 상완세갈래근에서 체중이 증가할수록 낮게 나타났다(p<0.05). 등심의 지방산 분석 결 과는 96 ~ 110kg 그룹에서 oleic acid, MUFA, MUFA/SFA가 높았고(p<0.05), 111 ~ 148kg 그룹에서 trans-vaccenic acid와 SFA가 높았지만(p<0.05), UFA는 낮았다(p<0.05).등심의 관능평가는 연도와 다 즙성이 96 ~ 110kg 그룹에서 높은 점수를 받았다(p<0.05).

The aim of this study was to develop the production of crossbred pigs suitable to the Korean consumers’demand. Crossbred (Jeju native pig × Landrace) pigs (n=175) at the age of 200 days, approximately classified into three slaughter weight groups (59~95 kg, 96~110 kg and 111~148 kg) were used to investigate the carcass traits and retail cuts characteristics. We have chosen longissimus dorsi, triceps brachii, biceps femoris, semimembranosus muscles, shoulder butt, thoracic vertebra (5-11th) and last thoracic vertebra for investigations of aforementioned parameters. The results showed that the 111~148 kg group had larger loin area, higher scores for meat color, quality and carcass grade than the other remaining groups (p<0.05). Weights of shoulder butt, rib, picnic shoulder, loin, belly, tenderloin, ham retail cuts, lean meat, fat and bone increased with increasing carcass weight (p<0.05). Ratios of shoulder butt, picnic shoulder, tenderloin, ham, lean meat, skin and bone in the 59~95 kg group were higher than that of the other groups (p<0.05). Ratios of belly in the 96~110 kg group were higher than that in the 59~95 kg group (p<0.05) but similar to the ratios of the 111~148 kg group. Total length, longest length and shortest length of belly increased with increasing carcass weight (p<0.05). Additionally, the longest width and shortest width of belly in 59~95 kg group were lower (p<0.05) than that in the other remaining groups. Length of shoulder butt increased with increasing carcass weight (p<0.05) whereas, the width of shoulder butt showed no differences between the groups. Weights of triceps brachii of picnic shoulder, biceps femoris and semimembranosus muscles of ham increased with increasing carcass weight (p<0.05). Overall, the crossbred pigs of 111~148 kg group possessed better quality and carcass grade however, the yield of belly in 96~110 kg group was higher than the other groups. Based on the consumption preference of Korean consumers therefore, the slaughter weight of crossbred pigs at ≥96 kg could produce higher economic benefit.

본 연구는 농촌진흥청 국립축산과학원에서 사육중인 제주재래돼지와 랜드레이스의 상호교차교배를 통해 생산된 417두의 F2집단을 대상으로 성장형질(생시체중, 3주령 체중, 10주령 체중, 20주령 체중)을 측정하고, 개체별 혈액으로부터 Illumina Porcine SNP 60k BeadChip을 이용하여 유전자형 분석을 실시하여 성장형질과 유전체 전장의 단일염기다형의 유전자형 간에 연관성을 알아보았다. 단일연기다형의 유전자형 분석은 돼지의 성염색체를 제외한 18개의 상염색체 내에 나타난 52,574개의 SNP표지인자 중다형성이 나타나지 않은 7,564개의 표지인자, 모든 개체에서 이형으로 나타난 47개 표지인자 및 결측률이 10 % 이상인 1,830개의 표지인자가 나타나 분석에 앞서 사전 제거를 실시하였으며, 남은 44,133개의 표지인자를 체중형질과 표지인자간 연관성 분석하는데 이용하였다. 체중에 영향하는 고정효과에 대해 일반선형모형을 설정하여 사전 보정을 실시하였으며, 여기서 얻어진 잔차값을 이용하여 표지인자와 월령별 체중간의 연관성 분석을 실시하였다. 분석결과 전장의 유전체 정보 중 통계적 판단의 오류를 고려하여 연관성이 강한(p <10-6)표지인자가 생시(BWB), 3주령(BW3), 10주령(BW10) 및 20주령(BW20) 체중에서 각각 657개, 846개, 49개, 122개로 추정되었다. 생시와 3주령 체중에 공통으로 유의적 영향을 하는 표지인자가 286개로 나타났으며, BWB와 BW10에서 5개, BWB와 BW20에서 8개, BW3와 BW10에서 13개, BW3과 BW20에서 11개, BW10과 BW20에서 1개로 나타났다. 또한 염색체별 성장형질에 영향하는 표지인자의 분포를 조사한 결과, 주령별 체중에 영향하는 표지인자는 전장의 유전체에 고르게 분포하는 것으로 조사되었으며, 특히 생시 및 3주령 체중에 영향하는 표지인자는 특정 염색체(SSC9)에서 고도의 통계적 유의차(p <10-15)를 나타내는 유전자 좌위가 있는 것으로 추정되었다.

This study was conducted to compare the carcass characteristics of native type black pigs (Black pigs) with those of commercial cross bred pigs (Commercial pigs) with the data collected from pig farms. 8364 and 33786 records were collected from Black pigs and the Commercial pigs, respectively. The Commercial pigs were mainly from three breed crosses of Yorkshire, Landrace and Duroc. Commercial pig data was subdivided into manual and machine sub data set on the judging method. Black pigs showed lower carcass weight (CWT) and thinner back fat thickness (BFT) than Commercial pigs. However, the ratio of BFT to CWT (BFT/CWT ratio) was higher in Black pigs than Commercial pigs. The carcass grades of Commercial pigs were mostly in A and B, C, and D in descending order, while the grades D or E were observed in most carcass of Black pigs. Barrow tended to be thicker in BFT and higher in BFT/CWT ratio than gilt both in Commercial and Black pigs, and gilt were higher in loin depth (LD) and Estimated Lean Yield Percentage (ELP) which were available only in the data by machine evaluation of Commercial pigs. Residual correlation coefficient (+0.496) between carcass weight and back fat thickness in Black pigs did not differ from those in Commercial pigs which were +0.434 and +0.414 in the data by manual and machine evaluation, respectively. The linear regression coefficients of back fat thickness on carcass weight were +0.364 mm in Black pigs, and +0.257 mm (manual evaluation) and +0.236 (machine evaluation) in Commercial pigs, which suggests relative accumulation rate of BFT to the growth of weight was faster in Black pigs than Commercial pigs.