Quality Characteristics and Composition of the Longissimus Muscle from Entire and Castrate Elk in Korea.

The objective of the research was to determine the chemical composition as well as the physicochemical properties of the longissimus muscle from Korean entire and castrate elk. Twelve elk stags were raised and fed on concentrate with ad libitum hay. All animals were equally divided into castrated and non-castrated (entire) males, and slaughtered at 5 year of age. It was found that entire elk, in comparison with castrate elk, had higher content of moisture and lower content of fat (p<0.05). Compared with entire males, the castrates had lower pH and shear force values (p<0.05). However, castrates had higher L*, a*, and b* values compared with entires (p<0.05). An analysis of the fatty acid profile revealed that the muscles of entire and castrate elk had the most abundant concentrations of the following fatty acids: palmitic acid (C16:0) of the saturated fatty acid, and oleic acid (C18:1n-9) of the unsaturated fatty acid. The entire elk contains higher proportions of linoleic acid (C18:3n6), eicosenoic acid (C20:1n9), and arachidonic acid (C20:4n6) (p<0.05). Cholesterol content in elk was not affected by castration. The predominant free amino acid was glutamic acid related to umami taste. It is apparent that the castrate animals carried higher content of histidine, isoleucine, and leucine than those of the entire group (p<0.05). In this study, it was concluded that venison quality of elk is affected by castration and these results can provide fundamental information for venison production.

A genome-wide scan for signatures of directional selection in domesticated pigs.

BACKGROUND: Animal domestication involved drastic phenotypic changes driven by strong artificial selection and also resulted in new populations of breeds, established by humans. This study aims to identify genes that show evidence of recent artificial selection during pig domestication. RESULTS: Whole-genome resequencing of 30 individual pigs from domesticated breeds, Landrace and Yorkshire, and 10 Asian wild boars at ~16-fold coverage was performed resulting in over 4.3 million SNPs for 19,990 genes. We constructed a comprehensive genome map of directional selection by detecting selective sweeps using an F ST-based approach that detects directional selection in lineages leading to the domesticated breeds and using a haplotype-based test that detects ongoing selective sweeps within the breeds. We show that candidate genes under selection are significantly enriched for loci implicated in quantitative traits important to pig reproduction and production. The candidate gene with the strongest signals of directional selection belongs to group III of the metabolomics glutamate receptors, known to affect brain functions associated with eating behavior, suggesting that loci under strong selection include loci involved in behaviorial traits in domesticated pigs including tameness. CONCLUSIONS: We show that a significant proportion of selection signatures coincide with loci that were previously inferred to affect phenotypic variation in pigs. We further identify functional enrichment related to behavior, such as signal transduction and neuronal activities, for those targets of selection during domestication in pigs.

mtDNA Diversity and Phylogenetic State of Korean Cattle Breed, Chikso.

In order to analyze the genetic diversity and phylogenetic status of the Korean Chikso breed, we determined sequences of mtDNA cytochrome b (cyt b) gene and performed phylogenetic analysis using 239 individuals from 5 Chikso populations. Five non-synonymous mutations of a total of 15 polymorphic sites were identified among 239 cyt b coding sequences. Thirteen haplotypes were defined, and haplotype diversity was 0.4709 ranging from 0.2577 to 0.6114. Thirty-five haplotypes (C1-C35) were classified among 9 Asia and 3 European breeds. C2 was a major haplotype that contained 206 sequences (64.6%) from all breeds used. C3-C13 haplotypes were Chikso-specific haplotypes. C1 and C2 haplotypes contained 80.5% of cyt b sequences of Hanwoo, Yanbian, Zaosheng and JB breeds. In phylogenetic analyses, the Chikso breed was contained into B. taurus lineage and was genetically more closely related to two Chinese breeds than to Korean brown cattle, Hanwoo. These results suggest that Chikso and Hanwoo have a genetic difference based on the mtDNA cyt b gene as well as their coat color, sufficient for classification as a separate breed.

Comparisons of longissimus muscle metabolic enzymes and muscle fiber types in Korean and western pig breeds.

We compared differentially expressed genes and muscle fiber types in the longissimus muscles of Korean native pigs (KNP) and the western meat-producing breeds Landrace and Yorkshire. The KNP breed exhibited a higher muscle fat content and more red meat color as determined by the a(∗) (redness) value (P<0.01) and b(∗) (yellowness) value (P<0.05) compared to the western breeds. Using differential display RT-PCR, we detected two genes that were differentially expressed in skeletal muscle among the pig breeds. These genes were identified as NADH dehydrogenase subunit 1 and ATPase subunit 6 by cloning and sequencing analysis. Both of these genes are involved oxidative phosphorylation and therefore energy metabolism. The genes were more highly expressed in the KNP breed than in the other breeds, indicating that KNPs exhibit more oxidative metabolism than do the western breeds. We also analyzed the mRNA levels of myosin heavy-chain isoforms such as type I (oxidative), type IIb (glycolytic), and types IIa and IIx (intermediate) fibers using real-time RT-PCR. The mRNA levels of oxidative and intermediate fibers were elevated in the KNP breed, whereas the glycolytic fibers were more highly expressed in the Landrace and Yorkshire pigs. These results suggest that the elevated expression of the oxidation-related metabolism genes NADH dehydrogenase and ATPase is related to meat quality as indicated by a higher content of oxidative fibers and muscle fat, as well as redder meat color.

The effect of castration time on growth and carcass production of elk bulls.

The effects of castration time on growth and carcass traits of elk bulls were investigated. Twelve bulls at 5 years old were raised and fed on concentrate with ad libitum hay. All animals were allocated randomly to each of four treatment groups (3 heads/group). Groups of each treatment were castrated surgically in March, April or June and managed together with non-castration (entire) treatment. All elk bulls in the trial were slaughtered at same time. Growth parameters, carcass yield and composition were recorded. The total gain and average daily gain was higher when castrated in April (p < 0.05). The entire elk produced heaviest and highest in saddle and brisket portions (p < 0.05). It is apparent that the castrate animals carried more total fat weight and percentages than the entire males (p < 0.05). It was found that loin muscles from non-castrated elk, in comparison with those from castrated one, had higher content of moisture and lower content of fat (p < 0.05). In this study, growth parameters, carcass yields and chemical composition were greatly affected by castration time.