Development of nutrigenomic based precision management model for Hanwoo steers.

Focusing high marble deposition, Hanwoo feedlot system uses high-energy diet over the prolonged fattening period. However, due to the individual genetic variation, around 40% of them are graded into inferior quality grades (QG), despite they utilized the same resources. Therefore, focusing on development of a nutrigenomic based precision management model, this study was to evaluated the response to the divergent selection on genetic merit for marbling score (MS), under different dietary total digestible nutrient (TDN) levels. Total of 111 calves were genotyped and initially grouped according to estimated breeding value (high and low) for marbling score (MS-EBV). Subsequently, managed under two levels of feed TDN%, over the calf period, early, middle, and final fattening periods following 2 × 2 factorial arrangement. Carcasses were evaluated for MS, Back fat thickness (BFT) and Korean beef quality grading standard. As the direct response to the selection was significant, the results confirmed the importance of initial genetic grouping of Hanwoo steers for MS-EBV. However, dietary TDN level did not show an effect (p > 0.05) on the MS. Furthermore, no genetic-by-nutrition interaction for MS (p > 0.05) was also observed. The present results showed no correlation response on BFT (p > 0.05), which indicates that the selection based on MS-EBV can be used to enhance the MS without undesirable effect on BFT. Ultimate turnover of the Hanwoo feedlot operation is primarily determined by the QGs. The present model shows that the initial grouping for MS-EBV increased the proportion of carcasses graded for higher QGs (QG1++ and QG1+) by approximately 20%. Moreover, there appear to be a potential to increase the proportion of QG 1++ animals among the high-genetic group by further increasing the dietary energy content. Overall, this precision management strategy suggests the importance of adopting an MS based initial genetic grouping system for Hanwoo steers with a subsequent divergent management based on dietary energy level.

Assessment of carcass and meat quality of longissimus thoracis and semimembranosus muscles of Hanwoo with Korean beef grading standards.

The carcass traits, meat quality traits, and fatty acid profile of two muscles, longissimus thoracis (LT) and semimembranosus (SM), in Hanwoo steers were investigated against the Korean beef quality grade (QG) and yield grade (YG) standards. Back fat thickness and carcass weight most affect the YGs, while the marbling score is the primary determinant of the QGs. The muscle type greatly influenced the meat qualities, sensory properties, and fatty acid profiles of Hanwoo meat. In terms of sensory aspects, the muscle type affected the QG for tenderness and juiciness, with the LT being more desirable than the SM for all the sensory attributes. SM meat is potentially beneficial for human health because it has a lower amount of unhealthy saturated fatty acids and a greater amount of healthier polyunsaturated fatty acids, especially essential fatty acids, than the LT. The present study indicates that carcass based common grading system does not reflect the real value of SM meat.

Genetic diversity and population structure of the Sapsaree, a native Korean dog breed.

BACKGROUND: The Sapsaree is a breed of dog (Canis familiaris) native to Korea, which became perilously close to extinction in the mid-1980s. However, with systematic genetic conservation and restoration efforts, this breed was rescued from extinction and population sizes have been gradually increasing over the past few decades. The aim of this study was to ascertain novel information about the genetic diversity, population structure, and demographic history of the Sapsaree breed using genome-wide single nucleotide polymorphism data. We characterized the genetic profile of the Sapsaree breed by comparison with seven foreign dog breeds with similar morphologies to estimate genetic differentiation within and among these breeds. RESULTS: The results suggest that Sapsarees have higher genetic variance compared with the other breeds analyzed. The majority of the Sapsarees in this study share a discrete genetic pattern, although some individuals were slightly different, possibly as a consequence of the recent restoration process. Concordant results from analyses of linkage disequilibrium, effective population size, genetic diversity, and population structural analyses illustrate a relationship among the Sapsaree and the Tibetan breeds Tibetan terrier and Lhasa Apso, and a small genetic introgression from European breeds. The effective population size of the Sapsaree has contracted dramatically over the past generations, and is currently insufficient to maintain long-term viability of the breed's genetic diversity. CONCLUSIONS: This study provides novel insights regarding the genetic diversity and population structure of the native Korean dog breed Sapsaree. Our results suggest the importance of a strategic and systematic approach to ensure the genetic diversity and the authenticity of the Sapsaree breed.