• PNF and Movement
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• 제6권2호
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• pp.51-57
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• 2008

Purpose : Mechanical stress activates signaling cascades and leading to a specific response of a network of signaling pathways. The purpose of this study is to review the effect of mechanical stress-induced adaptation in skeletal muscle involves a biological mechanisms. Methods : This is literature study with Pubmed, Medline and books. Results : Skeletal muscle tissue demonstrates a malleability and may adjust its metabilic response, vascularization and neuromuscular characteristic makeup in response to alteration in functional demands. The adaptation in skeletal muscle involoves a multitude of signalling mechanisms related with insuline-like growth factor, vascular endothelial growth factor, neurotrophins. Conclusions : The identification of the basic relationships underlying the malleability of skeletal muscle tissue is likely to be of relevance for our understanding with PNF technique.

• Asian-Australasian Journal of Animal Sciences
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• 제22권7호
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• pp.937-942
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• 2009

The aim of this study was to analyze the effects on growth and muscle development during the growing period of the sex-linked dwarf gene in the background of a Taiwan Country chicken strain, L2, selected for egg production. Eight crossbred males, heterozygous for the DW*DW mutation, were each backcrossed to six females of the L2 strain to produce two genotypes of BC females, either normal (DW*N+/-) or dwarf (DW*DW/-). The experiment included 251 normal and 207 dwarf pullets. The effect of the dwarf gene on body weight and shank length was highly significant from 2 weeks of age. The reduction of body weight by the dwarf gene reached 34.8% and 37.4% as compared to normal sibs at 16 and 20 weeks of age, respectively. Parameters of the growth curve were estimated: the age at inflection (TI) was higher in normal pullets (66.9 days) than in dwarf pullets (61.2 days). A significant effect of the dwarf gene on single muscle fiber cross-section area was found from 12 weeks of age onwards, whereas the dwarf gene had no effect on the total number of muscle fibers. Comparing the effect of the dwarf gene on shank length at different ages revealed an earlier effect on skeleton growth, observed from 2 weeks of age, than on muscle development, which was affected from 8 to 12 weeks of age.

• Asian-Australasian Journal of Animal Sciences
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• 제29권9호
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• pp.1331-1337
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• 2016

The aim of this study was to compare the growth performance, fiber characteristics of the pectoralis major muscle, and meat quality characteristics in the heavy weight (HW) and random bred control (RBC) quail lines and genders. The HW male exhibited more than two times greater body (245.7 vs 96.1 g, p<0.05) and pectoralis major muscle (PMW; 37.1 vs 11.1 g, p<0.05) weights compared to the RBC female. This growth performance in the HW line was associated with a greater muscle fiber area (1,502 vs $663.0{\mu}m^2$, p<0.001) compared to the RBC line. Greater muscle mass of the HW male was accompanied by a higher percentage of type IIB fiber compared to the HW female (64.0% vs 51.0%, p<0.05). However, muscle fiber hyperplasia (increase in fiber number) has had a somewhat limited effect on PMW between the two lines. On the other hand, the HW line harboring a higher proportion of type IIB fiber showed rapid pH decline at the early postmortem period (6.23 vs 6.41, p<0.05) and lighter meat surface (53.5 vs 47.3, p<0.05) compared to the RBC line harboring a lower proportion of type IIB fiber. There were no significant differences observed in the measurement of water-holding capacity including drip loss (2.74% vs 3.07%, p>0.05) and cooking loss (21.9% vs 20.4%, p>0.05) between the HW and RBC lines. Therefore, the HW quail line developed by selection from the RBC quail, was slightly different in the meat quality characteristics compared to the RBC line, and a marked difference was found in growth performance between the two quail lines.

• 한국가금학회지
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• 제48권4호
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• pp.255-265
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• 2021

지구 온난화와 여름철 고온 환경은 육계의 성장 능력뿐만 아니라 동물복지에도 큰 영향을 미친다. 성장과 근육발달 중심으로 선발된 육계는 열 스트레스를 완화시키는 심장과 폐와 같은 핵심 장기들은 비례적으로 성장하지 못하여 급격한 환경 온도 변화에 대처하기가 어렵다. 환경 온도의 변화는 배아 발달 기간 및 부화 초기까지 근육생성에 큰 영향을 준다. 위성세포 또한 고온 스트레스에 매우 민감하다. 고온스트레스는 위성세포의 증식 및 분화 활동에 영향을 주고, 위성세포의 운명뿐만 아니라, 근육 성장 및 구조에 영향을 미친다. 부화 기간의 정교한 온도조절과 부화 초기 사육 환경 온도의 관리는 육계의 성장과 근육 발달, 그리고 동물복지를 결정하는 데 가장 중요한 핵심 요소이다.

• Asian-Australasian Journal of Animal Sciences
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• 제18권10호
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• pp.1492-1497
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• 2005

The goal of the trial was to evaluate the effects of ractopamine (20 ppm in the ration) given pregnant sows during three different pregnancy stages (T1: 25 to 50 d; T2: 50 to 80 d; T3: 25 to 80 d of gestation, and T4: control-no ractopamine) on fetal muscle development (through counts of the number of fibers of the semitendinosus muscle), on the growth and carcass characteristics of the progeny. Forty eight weaned piglets (12 per treatment) were assessed for number of muscle fibers, while performance and carcass characteristics were evaluated on a separate 48 animals (12 per treatment) grown to 100 kg. Animals produced by sows treated from 25 to 50 d of pregnancy (T1) resulted in non-significant increase of 6.85% in the number of muscle fibers in the semitendinosus muscle when compared to animals from the control group. Performance results were significantly different (p<0.05), and animals produced by sows from the T1 group gained more weight during the growth I stage (25 to 50 kg) and during the total period (6 to 100 kg) (991 vs. 903 grams, and 844 vs. 772 grams, respectively) when compared to controls. For carcass characteristics, results showed that animals produced by the T1 group of sows were heavier at slaughter (p<0.05) when compared to the controls (T4) (100.17 vs. 93.09 kg). There was a positive correlation between number of muscle fibers and bodyweights, carcass weights, Longissimus dorsi muscle depth and dressing out (0.80, 0.86, 0.67, and 0.50, respectively). Sows treated with ractopamine between 25 to 50 d of pregnancy produced piglets that performed better and had superior carcass characteristics than those produced by untreated sows. The ractopamine used for pregnancy sows (25 to 50 d) can be indicated as a device to increase the progeny performance.

• 한국식품영양과학회지
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• 제42권6호
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• pp.904-910
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• 2013

본 연구는 젊은 성인을 대상으로 운동 목적에 따른 영양섭취 실태를 조사하고자 수행되었다. 규칙적으로 운동하고 있는 20~30대 남녀를 대상으로 운동 목적에 따라 근육증가군 107명과 체중감소군 107명을 나누어 비교 분석하였다. 그룹별 성별구성을 분석한 결과, 근육증가군은 주로 남성(75.2%)이 많은 반면 체중감소군은 여성(74.3%)이 많이 분포하고 있었다. BMI 판정결과 두 그룹간의 유의적인 차이는 없었으며, 체중감소군의 절반 이상(56%)이 저체중 또는 정상체중으로 나타났다. 근육증가군의 하루 운동시간 및 규칙적으로 운동한 기간이 체중감소군에 비하여 유의적으로 많았다(p<0.01). 영양지식의 상태는 근육증가군의 점수가 체중 감소군에 비하여 유의적으로 높은 것으로 나타났다(p<0.05). 식행동 또한 근육량 증가군의 점수가 체중감소군에 비하여 유의적으로 높았다(p<0.05). 영양섭취 상태를 살펴보면, 한국인영양섭취기준과 비교하였을 때 근육증가군의 에너지 섭취비율이 에너지필요추정량의 83.72%로 체중감소군의 74.53%에 비하여 유의적로 높았다(p<0.01). 권장섭취량에 대한 단백질 섭취비율은 근육증가군이 199.62%, 체중감소군은 136.36%로 나타났으며 근육증가군이 체중감소군에 비해 유의적으로 매우 많은 양을 섭취하고 있었다(p<0.001). 권장섭취량에 대한 칼슘 섭취비율은 근육증가군이 67.75%, 체중감소군은 68.64%로 조사되었으며, 두 군 모두 권장섭취량과 비교하여 매우 부족한 수준으로 나타났다. 이와 같이 본 연구에서는 근육증가를 목적으로 운동하는 경우 과량의 단백질을 섭취하고 있었으며, 체중감소를 목적으로 운동하는 경우 필요량에 미치지 못하는 에너지 섭취를 하는 것으로 나타났다.

• Asian-Australasian Journal of Animal Sciences
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• 제14권12호
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• pp.1794-1802
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• 2001

Biotechnology will play critical role in improving animal productivity. Animal growth rate and muscle deposition potential can be greatly improved by the application of biotechnology and biotechnological products. Administration of recombinant somatotropin (ST) or other compounds such as IGF-1 and growth hormone-releasing peptides (GHRPs) can enhance growth rate and carcass lean percentage. Gene transfer offers a powerful approach to manipulate endocrine system and metabolic pathways toward faster growth and better feed efficiency. Biotechnology is also extensively used for improving metabolism and activity of gut microorganisms for better nutrient digestibility. Knockout of growth-inhibiting genes such as myostatin results in considerable acceleration of body weight and muscle growth. Animal growth can also be improved by the use of gene therapy. Immunomodulation is another approach for efficient growth through controlling the activity of endogenous anabolic hormones. All the above aspects will be discussed in this review.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권1호
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• pp.44-47
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• 2000

Cell growth and DNA synthesis were studied from a cultured early- and late- pas- sage mouse aorta smooth muscle cell (MASMC) because the proliferation of vascular smooth muscle cell (VSMC) is a key factor in development of atherosclerosis. In this study, the cells were cultured in fetal bovine serum (FBS) and stimulated by growth factors such as thrombin and platelet-derived growth factor-BB (PDGF-BB). Compared to the number of early-passage MASMC (passage 3 to 9) the number of late-passage MASMC (passage 30 to 40) in a normal serum state was increased 2 fold at Day 1, 3 and 6 in culture, respectively. Incorporation of $[^3H]$ thymidine into DNA induced by serum, PDGF and thrombin in late-passage MASMC was greater than those in early-passage MASMC. We also examined whether intracellular zinc levels would be an aging factor or not. The intracellular zinc level in early- and late-passage MASMC was monitored by using the zinc probe dye N-(6-methoxy-8-quinolyl)-p-toluenesulfonamide. It is interested that late-passage MASMC increased the intracellular fluorescence level of zinc, more than the early passage MASMC did. The alterations of intracellular zinc level occur concurrently with changes in MASMC proliferation rate during aging. This data suggest that the age-associated changes in zinc concentrations may provide a new in vitro model for the study of smooth muscle cell differentiation.

• Molecules and Cells
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• 제28권5호
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• pp.495-499
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• 2009

Although insulin-like growth factor-I (IGF-I) and androgen receptor (AR) are well known effectors of skeletal muscle, the molecular mechanism by which signaling pathways integrating AR and IGF-I in skeletal muscle cells has not been previously examined. In this study, the role of PI3K/Akt on IGF-I-induced gene expression and activation of AR in skeletal muscle cells was investigated. C2C12 cells were treated with IGF-I in the absence or presence of inhibitors of PI3K/Akt pathway (LY294002 and Wortmannin). Inhibition of the PI3K/Akt pathway with LY294002 or Wortmannin led to a significant decrease in IGF-I-induced AR phosphorylation and total AR protein expression. Furthermore, IGF-I-induced AR mRNA and skeletal ${\alpha}-actin$ mRNA were blocked by LY294002 or Wortmannin. Confocal images showed that IGF-I-induced AR translocation from cytosol to nucleus was inhibited significantly in response to treatment with LY294002 or Wortmannin. The present results suggest that modulating effect of IGF-I on AR gene expression and activation in C2C12 mouse skeletal muscle cells is mediated at least in part by the PI3K/Akt pathway.

• Archives of Pharmacal Research
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• 제27권3호
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• pp.324-333
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• 2004

To determine whether Insulin-like growth factor (IGF-I) treatment represents a potential means of enhancing the survival of cardiac muscle cells from adriamycin (ADR)-induced cell death, the present study examined the ability of IGF-I to prevent cell death. The study was performed utilising the embryonic, rat, cardiac muscle cell line, H9C2. Incubating cardiac muscle cells in the presence of adriamycin increased cell death, as determined by MTT assay and annexin V-positive cell number. The addition of 100 ng/mL IGF-I, in the presence of adriamycin, decreased apoptosis. The effect of IGF-I on phosphorylation of PI, a substrate of phosphatidylinositol 3-kinase (PI 3-kinase) or protein kinase B (AKT), was also examined in H9C2 cardiac muscle cells. IGF-I increased the phosphorylation of ERK 1 and 2 and $PKC{\;}{\zeta}{\;}kinase$. The use of inhibitors of PI 3-kinase (LY 294002), in the cell death assay, demonstrated partial abrogation of the protective effect of IGF-I. The MEK1 inhibitor-PD098059 and the PKC inhibitor-chelerythrine exhibited no effect on IGF-1-induced cell protection. In the regulatory subunit of PI3K-p85- dominant, negative plasmid-transfected cells, the IGF-1-induced protective effect was reversed. This data demonstrates that IGF-I protects cardiac muscle cells from ADR-induced cell death. Although IGF-I activates several signaling pathways that contribute to its protective effect in other cell types, only activation of PI 3-kinase contributes to this effect in H9C2 cardiac muscle cells.