Biomedical subjects

K H Myung

Publications and source records attributed to K H Myung.

4 recordsLinked to original sources

PubMed2006

Effects of 25-hydroxyvitamin D3 and manipulated dietary cation-anion difference on the tenderness of beef from cull native Korean cows.

In this study, we characterized the effects of 25-hydroxyvitamin D3 (25-OH D3) and manipulated dietary cation-anion difference (DCAD) on the performance, urine pH, serum constituents, carcass traits, tissue residual vitamin D and its metabolites, beef tenderness, and mRNA and protein concentrations of Ca-dependent proteinases in LM using 24 cull native Korean cows. The cows were divided into 3 groups of 8: control, 25-OH D3 supplemented (25-OH D3), and manipulated DCAD plus 25-OH D3 supplemented (DCAD+25-OH D3). Cows receiving 25-OH D3 or DCAD+25-OH D3 were dosed with 125 mg of 25-OH D3 6 d before slaughter. The manipulated DCAD (-10 mEq/100 g of DM) diet was fed from 20 to 6 d (14 d) before slaughter. The DCAD+25-OH D3 treatment decreased urine pH and increased serum Ca concentrations. Although the vitamin D concentrations in LM, liver, and kidney were not affected by 25-OH D3 or DCAD+25-OH D3, muscle tissue 25-OH D3 concentrations were increased by both regimens. Serum 25-OH D3 concentrations were increased by 25-OH D3 supplementation, and the increase was even greater for DCAD+25-OH D3. The same pattern was observed for serum 1,25- (OH)2 D3. However, the LM concentration of 1,25-(OH)2 D3 was less for DCAD+25-OH D3 than for control. Although Ca concentrations of LM increased numerically in response to 25-OH D3 supplementation, no statistical differences in Warner-Bratzler shear force or sensory traits of LM were detected. The LM of cows receiving 25-OH D3 with or without manipulated DCAD had greater concentrations of mu-calpain and m-calpain mRNA, whereas the reverse was observed for calpastatin mRNA. Expression of mu-calpain protein was increased relative to control by DCAD+25-OH D3. The amount of 25-OH D3 and manipulated DCAD administered to cull native Korean cows was insufficient to improve tenderness of beef by increasing muscle Ca concentration. However, DCAD+25-OH D3 induced greater expressions of mu-calpain protein as well as mRNA.

Animal Feed↗

PubMed2005

Effects of propylene glycol on carcass traits and its related gene expression in Korean native steers.

The effects of propylene glycol (PEG) on performance, ruminal fermentation, blood glucose and insulin, carcass traits, and abundance of IGF-1 mRNA in LM and leptin mRNA in adipose tissue were examined in 20 Korean native steers, with 10 each in control and PEG-fed groups, respectively. Propylene glycol mixed with concentrate diet was provided daily at a rate of 2.5 mL/kg BW(0.75). Experimental animals were fed a concentrate diet to 1.8% of BW twice daily plus rice straw ad libitum during the 4-mo period before marketing. Daily DMI and ADG did not differ between control and PEG-fed steers. Steers receiving PEG displayed an increase (P = 0.044) in propionate concentration, whereas acetate concentration decreased (P = 0.032). Although blood glucose was not affected, serum insulin was increased (P = 0.047) by PEG feeding. Propylene glycol did not affect carcass weight, 13th-rib fat depth, marbling score, or lipid content of LM. The backfat of PEG-fed steers did not differ in leptin mRNA from control steers, whereas increased leptin mRNA was found in i.m. fat with PEG feeding. There was no treatment effect on the level of IGF-1 mRNA in the LM of the tested steers. These results indicate that the amount of PEG fed to steers was not sufficient to improve marbling score through enhanced ruminal propionate and insulin. The role of increased i.m. leptin mRNA level in PEG-fed steers remains to be further elucidated.

Adipose Tissue↗

PubMed1997

Compensatory growth in dairy heifers: the effect of a compensatory growth pattern on growth rate and lactation performance.

The objective of this study was to improve the efficiency of growth and lactation performance of dairy heifers fed for a stair-step growth pattern. Twenty-four young Holstein heifers were randomly assigned to either control or test groups. The test group was fed according to a schedule of 3, 2, 4, 2, 5 and 2 mo in which feed intake was alternately 20% below or 25% above requirements. Heifers that were subjected to the stair-step growth pattern gained more body weight and consumed less dry matter, resulting in improved efficiency of growth compared with that of controls (7.8% vs. 8.3%). First estrus, first conception, gestation period, services per conception, and calving difficulty (dystocia) were not affected by stair-step growth. Concentration of growth hormone in blood serum was elevated during feed restriction for the test heifers; however, during refeeding, growth hormone was decreased compared with that in the blood serum of control heifers. Mammary tissues obtained by biopsy from heifers in middle and late pregnancy were used for chemical composition analysis. Stair-step growth increased DNA, RNA, protein, the ratio of RNA to DNA, and the ratio of protein to DNA. Lipid decreased in the mammary tissue of test heifers in late pregnancy (9.5 mo). Heifers in the test group yielded approximately 9% more milk than did heifers in the control group. These results indicate that compensatory growth can contribute to the improvement of growth efficiency and lactation performance.

Animal Nutritional Physiological Phenomena↗

PubMed1984

The innominate line.

High-resolution CT scan is used to clearly identify the components of the innominate line. Fourteen patients with abnormal innominate lines are then examined and used to illustrate the three pathological processes affecting the innominate line, namely, destruction, hyperostosis and expansion.

Humans↗