出版者・発行元：Animal Science Journal  

DOI： 10.1111/asj.13327

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出版者・発行元：John Wiley & Sons Australia, Ltd  

出版者・発行元：日本家禽学会  

<p>Insulin stimulates protein synthesis in skeletal muscles. Protein synthesis is controlled by the mechanistic target of rapamycin (mTOR) signaling in skeletal muscles. This study was conducted to investigate the effect of insulin on protein synthesis and mTOR signaling in chick myotube cultures. Chick myotubes were incubated with insulin (1 <i>µ</i>g/m<i>l</i>) for 1 h. Protein synthesis, measured using the surface sensing of translation method, was significantly increased by insulin. The phosphorylation of AKT (Thr308 and Ser473), p70 ribosomal S6 kinase 1 (S6K1, Thr389), S6 ribosomal protein (Ser235/236), and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1, Thr37/46) was also significantly increased by insulin. These results suggest that insulin stimulates protein synthesis via mTOR signaling (phosphorylation of AKT, S6K1, S6 ribosomal protein, and 4E-BP1) in chick myotube cultures.</p>

DOI： 10.2141/jpsa.0190082

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出版者・発行元：Animal Science Journal  

DOI： 10.1111/asj.13291

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出版者・発行元：General and Comparative Endocrinology  

DOI： 10.1016/j.ygcen.2019.113232

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出版者・発行元：Journal of Thermal Biology  

DOI： 10.1016/j.jtherbio.2019.04.016

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出版者・発行元：Animal Science Journal  

DOI： 10.1111/asj.13141

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本暖地畜産学会  

出版者・発行元：日本暖地畜産学会  

<p>本研究ではブロイラー用飼料としての加熱乾燥サツマイモ加工残さ（D-SPW）の栄養評価を行った．生のサツマイモ加工残さを加熱真空乾燥（72℃，6 時間，絶対圧 15 kpa）して D-SPW を調製した．14 日齢の雄ブロイラー 16 羽を対照区および D-SPW 区に分け，トウモロコシおよび大豆粕を主原料とする前期飼料（14 〜 28 日齢；CP，20％；ME，13.0 MJ/kg）および後期飼料（29 〜42 日齢；CP，18％；ME，13.0 MJ/kg）を自由摂取させた．D-SPW 区のブロイラーには，前期および後期飼料にそれぞれ 28.4％および 25.5％の D-SPW を配合して与えた．D-SPW 区のブロイラーの栄養素の代謝能力は，脂質を除いて，対照区より低かったが，全期間の成育成績に区間差はなかった．浅胸筋および大腿筋の pH は死後 1 および 48 時間で，D-SPW 区が対照区よりも高い値を示した．浅胸筋，大腿筋および腹腔内脂肪の黄色度は D-SPW 区が対照区より低い値を示し，黄色度が最も D-SPW の影響を受けやすいことが示された．明度および赤色度に対する D-SPW の影響は限定的であった．浅胸筋および大腿筋の脂質含量は，D-SPW 区が対照区より高い値を示した．以上より D-SPW は，トウモロコシの部分的な代替に適したブロイラー用の飼料資材であるが，脂肪含量が高くて黄色度の低い鶏肉が生産されることが示された．</p>

DOI： 10.11461/jwaras.62.107

出版者・発行元：日本暖地畜産学会  

<p>かごしま黒豚（バークシャー種：黒豚），LWD 三元交雑種（白豚），およびカナダ産LWD（輸入豚）の各ロースブロックを用いて，官能評価および理化学検査を行い，得られた結果を比べた．"香りの好ましさ"において，黒豚肉および白豚肉は高い評価を得たが，これらの豚肉からは輸入豚肉より多くの種類の臭気物質が検出された．また黒豚肉は，"噛み切りやすさ"および"咀嚼しやすさ"において高い評価を得ると同時に，輸入豚肉より有意に低い遠心水分遊離率を示した．一方で黒豚肉では，遊離のグルタミン酸（旨味）とトレオニン（甘味）の相対含量が数倍高く，また遊離のプロリン（甘味）とアラニン（甘味）の相対含量も有意に高かったが，"旨味の強さ・好ましさ"は白豚肉および輸入豚肉と同等の評価であった．背脂肪の脂肪酸組成においては，黒豚肉で多価不飽和脂肪の割合が低いことが認められた．総合評価は黒豚肉＞白豚肉＞輸入肉の順となった．</p>

DOI： 10.11461/jwaras.62.17

出版者・発行元：General and Comparative Endocrinology  

DOI： 10.1016/j.ygcen.2018.05.028

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出版者・発行元：Journal of Agricultural and Food Chemistry  

DOI： 10.1021/acs.jafc.8b00853

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出版者・発行元：公益社団法人 日本畜産学会  

<p>本研究では，ブロイラー初生ヒナに対する飼料給与の開始日齢が出荷時の肉質に及ぼす影響を調べた．0日齢ブロイラー（チャンキー系ROSS308オス）12羽を2区に分け，飼料給与を0日齢から開始した対照区と2日齢から開始した遅延区とした．両区ともに平均体重が2.2kgに達した時点で屠殺・解体した．平均体重が2.2kgに達した日齢は，対照区が55日であったのに対して，遅延区では60日であった．遅延区のムネ肉は，抗酸化酵素の遺伝子発現量およびα-トコフェロール含量に低下がみられ，脂質過酸化度が増加した．48時間保蔵後のドリップロスは遅延区で増加し，遅延区のムネ肉の色値は，明度が高く，赤色度が低かった．さらに，ムネ肉スープの呈味成分の分析を行った結果，遅延区のムネ肉は，対照区と比較して旨味および旨味コクが低い値を示した．以上より，飼料給与の開始日齢は，ブロイラーのムネ肉の脂質過酸化度やドリップ量，肉色，呈味成分に影響することが示唆された．</p>

DOI： 10.2508/chikusan.89.191

出版者・発行元：Comparative Biochemistry and Physiology -Part A : Molecular and Integrative Physiology  

DOI： 10.1016/j.cbpa.2017.05.013

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出版者・発行元：Comparative Biochemistry and Physiology -Part A : Molecular and Integrative Physiology  

DOI： 10.1016/j.cbpa.2016.12.014

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出版者・発行元：日本家禽学会  

<p>The expression of atrogin-1/MAFbx, a muscle-specific E3 ubiquitin ligase, is increased in catabolic conditions that result in muscle atrophy. The expression of atrogin-1/MAFbx mRNA is also decreased by the insulin-like growth factor-I (IGF-I) in mammalian skeletal muscle cell cultures. This study investigated the effect of IGF-I on the expression of atrogin-1/MAFbx in chicken skeletal muscle cell cultures. Chick myotubes were incubated with IGF-I for 1, 6, or 24 h. Protein content was increased by IGF-I (100 ng/m<i>l</i>) and incubated for 24 h in chick myotubes. The expression of atrogin-1/MAFbx mRNA decreased in the presence of IGF-I (1, 10, and 100 ng/m<i>l</i>) for 6 h in chick myotubes. The expression of the m-calpain large subunit and cathepsin B mRNA was not decreased by IGF-I. Phosphorylation of Akt and FOXO1 increased in the presence of IGF-I (100 ng/m<i>l</i>) for 1 h in chick myotubes. These results indicate that IGF-I suppresses atrogin-1/MAFbx mRNA expression by phosphorylation of Akt and FOXO1, resulting in an increase in muscle growth in chick myotube cultures.</p>

DOI： 10.2141/jpsa.0160141

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出版者・発行元：Bioscience, Biotechnology and Biochemistry  

DOI： 10.1080/09168451.2017.1383846

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出版者・発行元：日本養豚学会  

<p>かごしま黒豚の背脂肪厚改善による上物率向上の検討を行うために，まず鹿児島県内の2カ所の食肉処理場における枝肉成績に関する調査を行い，バークシャー種（黒豚，調査対象46,724頭）はバークシャー種以外（白豚，調査対象342,787頭）に比べ，背脂肪厚（厚脂）による格落割合が高く（黒豚28%，白豚13%），上物率は低い（黒豚52%，白豚60%）ことを明らかにした。次に，かごしま黒豚の去勢雄と雌を，単飼−制限給餌下で肥育した場合，あるいは雌雄別群飼−間欠給餌下で肥育した場合でも，去勢雄の方が雌より背脂肪が厚くなることを確認した。次に，肥育後期のかごしま黒豚の背脂肪厚を改善する飼養管理方法の確立を目的とした実証試験を生産農場において行った。TDN76%の黒豚用肥育後期用飼料を体重80kgから間欠給餌した間欠区，同飼料を体重70kgから制限給餌したT76区，TDN70%の黒豚用肥育後期用飼料を体重70kgから制限給餌したT70区の3つの飼養区（30頭/区）を設け，さらに各飼養区にそれぞれ去勢雄群（10頭），雌群（10頭），混飼群（去勢雄5頭＋雌5頭）を設けて肥育試験を行った。その結果，厚脂による格落率は去勢雄群で間欠区，T76区，T70区でそれぞれ80%，67%，50%であったが，混飼群では20%，10%，10%となった。上物率も，去勢雄群で間欠区，T76区，T70区でそれぞれ20%，33%，50%であったが，混飼群では80%，80%，70%となった。また，全飼養区において，雌雄別飼条件では去勢雄群が雌群よりも背脂肪が厚かったが（P<0.05），混飼条件では有意差はなかった。これらの結果から，かごしま黒豚の去勢雄は雌よりも背脂肪厚による格落ちが多いが，雌雄混飼にすること，後期用飼料への切替時期を早めること，後期用飼料のTDNを低減させることで，背脂肪厚を改善して上物率を向上させることができる可能性が示された。</p>

DOI： 10.5938/youton.54.4_168

出版者・発行元：Animal Science Journal  

DOI： 10.1111/asj.12541

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出版者・発行元：Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology  

DOI： 10.1007/s00360-015-0957-x

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出版者・発行元：Animal Science Journal  

DOI： 10.1111/asj.12437

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出版者・発行元：Bioscience, Biotechnology and Biochemistry  

DOI： 10.1080/09168451.2016.1162088

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出版者・発行元：日本家禽学会  

<p>The objective of the present study was to examine the effects of nano-selenium on growth performance, antioxidative status, and immune function in broiler chickens reared under thermoneutral (22±1°C) or high ambient temperature (35±1°C) conditions. Thirty-six broiler chicks at 15d old were randomly divided into 6 treatments in a 3×2 factorial design. The main factors included the dietary supplementation (basal diet without Se supplementation [control], basal diet with 0.3 mg of nano-elemental Se per kilogram of diet [nano-Se], and basal diet with 0.3 mg of sodium selenite per kilogram of diet [SSe]) and the ambient temperature challenge (22±1°C or 35±1°C). The birds were given the experimental diets from 15 to 30 d of age. High ambient temperature significantly depressed body weight gain, feed intake, feed conversion ratio, breast muscle weight, and abdominal fat weight, while feeding nano-Se clearly alleviated these negative effects of high ambient temperature. In addition, feeding nano-Se increased glutathione peroxidase mRNA expression in liver and alleviated the negative effects of high ambient temperature via reducing the malondialdehyde content in liver and breast muscle. Furthermore, feeding nano-Se increased mRNA expression of cytokine genes (interleukins 2 and 6) under both thermoneutral and high ambient temperature conditions. Under both thermoneutral and high-temperature conditions, broiler chickens fed nano-Se had higher Se and vitamin E concentrations in breast muscle than broiler chickens fed the control diet. In contrast, feeding SSe at the same dose as nano-Se did not alleviate the negative effects of high ambient temperature on broiler chickens. In conclusion, dietary supplementation with nano-Se at 0.3 mg/kg diet might enhance growth performance by improving antioxidative or immune properties in broilers reared under high ambient temperature.</p>

DOI： 10.2141/jpsa.0150133

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出版者・発行元：Bioscience, Biotechnology and Biochemistry  

DOI： 10.1080/09168451.2016.1158629

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出版者・発行元：Animal Science Journal  

DOI： 10.1111/asj.12281

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出版者・発行元：General and Comparative Endocrinology  

DOI： 10.1016/j.ygcen.2014.12.002

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出版者・発行元：Bioscience, Biotechnology and Biochemistry  

DOI： 10.1080/09168451.2015.1032883

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出版者・発行元：World's Poultry Science Journal  

DOI： 10.1017/S0043933914000907

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出版者・発行元：General and Comparative Endocrinology  

DOI： 10.1016/j.ygcen.2014.07.023

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

出版者・発行元：Veterinarni Medicina  

DOI： 10.17221/7818-VETMED

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出版者・発行元：Egyptian Journal of Neurology, Psychiatry and Neurosurgery  

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出版者・発行元：日本家禽学会  

This study was conducted to evaluate the effects of dietary supplementation with <i>Aspergillus awamori </i>on the growth performance and antioxidative status in male broiler chickens exposed to high ambient temperatures. Twenty-four 15-d-old male broiler chickens were randomly divided into 2 dietary groups fed a corn-soybean meal-based diet supplemented without or with 0.05% of <i>Asp. awamori</i>. Six birds of each dietary group were kept under a thermoneutral condition (22°C), and 6 birds were exposed to heat stress (35°C, 9 h/d) for 15 d. Dietary <i>Asp. awamori </i>decreased feed intake and improved the feed conversion ratio in chickens kept at 22°C. Body weight gain and feed intake were decreased in chickens exposed to heat stress. There was no beneficial effect of dietary <i>Asp. awamori </i>on growth performance under the heat stress condition. However, the malondialdehyde content in skeletal muscle, as an index of lipid peroxidation, was decreased by dietary <i>Asp. awamori </i>in chickens kept at 22°C. Although the malondialdehyde content increased under the heat stress condition, dietary <i>Asp. awamori </i>alleviated the increased malondialdehyde. In addition, the <i>α</i>-tocopherol content in skeletal muscle was negatively affected by the exposure to heat stress, and dietary <i>Asp. awamori </i>recovered the reduction in the <i>α</i>-tocopherol content. Moreover, mRNA expression of glutathione peroxidase in liver was increased by dietary <i>Asp. awamori </i>under both of the thermal conditions. In conclusion, this study shows that dietary <i>Asp. awamori </i>improves the diminished antioxidative status under the heat stress condition partially because of its effect on the expression of hepatic antioxidant enzymes in broilers.

DOI： 10.2141/jpsa.0130154

記述言語：英語   掲載種別：研究論文（学術雑誌）  

出版者・発行元：日本家禽学会  

This study was conducted to examine the effects of a combined in-feed supplementation of <i>Aspergillus awamori </i>and <i>Saccharomyces cerevisiae </i>on growth and muscle protein metabolism and fatty acid profiles in broilers. Chicks (15 d old) were fed a basal diet as control, diets supplemented with 0.05% <i>A. awamori</i>, 0.10% <i>S. cerevisiae, </i>or a combination of both (7 birds/group) for 12 days. Growth of the birds was promoted by all treatments. Synergistic effects of <i>A. awamori </i>and <i>S. cerevisiae </i>were observed on body weight gain and feed conversion, breast muscle weight, and digestibility of dietary protein. Plasma 3-methylhistidine concentrations were decreased by <i>A. awamori </i>and <i>S. cerevisiae</i>, and synergistically by the combination. Gene expressions of proteolysis-related factors in muscle were reduced by all treatments. Conversely, mRNA expressions of myosin and actin were synergistically increased by the combination. Abdominal fat and plasma triglycerides were decreased by <i>A. awamori </i>and the combination, but not by <i>S. cerevisiae</i>, while muscle fat content was increased by all treatments. Interestingly, there was a decrease in saturated fatty acids and an increase in unsaturated fatty acids in muscle in all treatment groups. This change in fatty acid profile was partially related to mRNA expression of delta-6 fatty acid desaturase in the muscle. In conclusion, the combined supplementation of <i>A. awamori </i>and <i>S. cerevisiae </i>synergistically improves growth performance by promoting muscle protein metabolism. In addition, <i>A. awamori </i>and <i>S. cerevisiae </i>modify the muscle fatty acid profile.

DOI： 10.2141/jpsa.0120153

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出版者・発行元：BioMed Research International  

DOI： 10.1155/2013/594393

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

出版者・発行元：General and Comparative Endocrinology  

DOI： 10.1016/j.ygcen.2013.03.007

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

出版者・発行元：日本家禽学会  

In this study, the effect of β₂-agonist clenbuterol administration was investigated in chicks (<i>Gallus gallus domesticus</i>) at 6 days of age. Chicks were given single subcutaneous administration of clenbuterol dissolved in saline at a concentration of 1 mg/kg body weight. Twenty-four hours after clenbuterol administration, the ratio of skeletal muscle weight to body weight was increased in chicks treated with clenbuterol, while their body and heart weight were not affected. Although expressions of IGF-I and myostatin mRNA were not changed, the expression of atrogin-1/MAFbx mRNA was significantly decreased by clenbuterol administration. This observation suggested that administration of clenbuterol to neonatal chicks might increase the proportion of muscle mass to body mass. And the decreased expression of atrogin-1/MAFbx might be involved in the growth of skeletal muscle of chicks treated with clenbuterol.

DOI： 10.2141/jpsa.0120120

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

出版者・発行元：Japan Poultry Science Association  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

出版者・発行元：British Journal of Nutrition  

DOI： 10.1017/S0007114511007069

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出版者・発行元：Animal Science Journal  

DOI： 10.1111/j.1740-0929.2011.00999.x

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

出版者・発行元：Japan Poultry Science Association  

出版者・発行元：日本家禽学会  

A relationship between skeletal muscle proteolysis and mRNA expression of atrogin-1/MAFbx, a muscle-specific ubiquitin ligase, was examined in food-deprived broiler chickens. In response to food deprivation for 24 and 48h, body and muscle weights decreased in a time-dependent manner. Muscle free N<SUP>&tau;</SUP>-methylhistidine content, an index of myofibrillar proteolysis, was 1.8-fold and 2.5-fold greater than that of fed controls following 24 and 48h of food deprivation, respectively. Gene expression of atrogin-1/MAFbx drastically increased in response to food deprivation in a time-dependent manner. At 48h of food deprivation, the induction of atrogin-1/MAFbx mRNA expression level elevated up to 20-fold greater than that of fed controls. By contrast, mRNA expression levels of 20S proteasome C1 and C2 subunits tended to decrease with time. No significant difference was seen in the change of ubiquitin mRNA expression. A highly significant linear negative relationship (r<SUP>2</SUP>=0.754, <I>P</I><0.001) was found between atrogin-1/MAFbx expression and muscle mass, while a highly significant linear positive relationship (r<SUP>2</SUP>=0.784, <I>P</I><0.001) was found between atrogin-1/MAFbx expression and muscle free N<SUP>&tau;</SUP>-methylhistidine content. These results indicate that atrogin-1/MAFbx plays a critical role in the development of muscle proteolysis and its gene expression is a reliable index of muscle proteolysis in broiler chickens.

DOI： 10.2141/jpsa.010093

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

出版者・発行元：公益社団法人 日本農芸化学会  

We have found that shochu distillery by-product (SDBP) contains a growth promoting factor that can be extracted with ether. In the present study, we administered hexane-extracts of SDBP (HSDBP) to broiler chickens and observed changes in skeletal muscle protein degradation in order to clarify the mechanism of growth promotion due to SDBP feeding. The pectoralis superficial muscle weight was significantly increased by HSDBP feeding. Plasma <I>N</I><SUP>&tau;</SUP>-methylhistidine concentration was significantly decreased by HSDBP, showing that the rate of muscle protein degradation decreased. It was also found that the expression of mRNA of ubiquitin-proteasome system and calpain was decreased by HSDBP. These results indicate that growth promotion due to SDBP is caused by suppression of skeletal muscle protein degradation, which is related to the ubiquitin-ptoteasome system and calpain.

DOI： 10.1271/bbb.90587

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出版者・発行元：Japan Poultry Science Association  

出版者・発行元：Poultry Science  

DOI： 10.3382/ps.2007-00340

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出版者・発行元：Japan Poultry Science Association  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

出版者・発行元：Japan Poultry Science Association  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

出版者・発行元：Animal Science Journal  

DOI： 10.1111/j.1740-0929.2005.00304.x

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出版者・発行元：British Poultry Science  

DOI： 10.1080/00071660500255661

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出版者・発行元：Animal Science Journal  

DOI： 10.1111/j.1740-0929.2005.00293.x

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

出版者・発行元：American Journal of Physiology - Endocrinology and Metabolism  

DOI： 10.1152/ajpendo.00073.2004

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出版者・発行元：Japan Poultry Science Association  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

出版者・発行元：社団法人日本農芸化学会  

&nbsp;&nbsp;These experiments were done to clarify that the differential effects of thyroxine (T₄) and triiodothyronine (T₃) on skeletal muscle protein turnover are caused by their roles on ATP production. Primary cultured chick muscle cells were treated with a physiological level of T₄ (60 ng/ml), T₃ (12 ng/ml), or ATP (0.5 m<small>M</small>) for 6 days and the protein content, ATP production, proteasome activity, and myofibrillar protein breakdown were measured. The protein content measured as an index of cell growth was not affected by T₄, T₃, or ATP. The cellular ATP level was increased by T₃ and ATP, but not by T₄. Proteasome activity and <i>N</i>^τ-methylhistidine (MeHis) release measured as an index of myofiblillar protein breakdown was also increased by T₃ and ATP, but not by T₄. These results indicate that T₃ but not T₄ increases ATP production followed by an increase in proteasome activity, and thus stimulates myofibrillar proteolysis.<br>

DOI： 10.1271/bbb.67.2451

Scopus

PubMed

出版者・発行元：Japan Poultry Science Association  

出版者・発行元：British Poultry Science  

DOI： 10.1080/0007166031000085427

Scopus

出版者・発行元：社団法人日本農芸化学会  

&nbsp;&nbsp;This study was done to examine the effects of corticosterone, a glucocorticoid, on Ca²⁺ uptake, proteolysis, and Ca²⁺ channels in primary cultures of chick muscle cells, to clarify the mechanism of glucocorticoid action on muscle proteolysis. Chick muscle cells were incubated for 24 h in a medium containing corticosterone (30 ng/ml) when the cells were confluent (6 days). To examine the contribution of Ca²⁺ channels, nifedipine, a Ca²⁺ channels antagonist, was used. Ca²⁺ uptake measured with ⁴⁵CaCl₂ was increased three-fold by corticosterone, with a peak at 12 h after the treatment started. The growth of the cells estimated from the protein content and creatine kinase activity was not affected by corticosterone. Proteolysis, evaluated with [³H]tyrosine as a label of the protein and N^&tau;-methylhistidine release, was unchanged by corticosterone. However, the amount of easily releasable myofilament as a measure of myofibrillar disassembly in the muscle cells was increased by corticosterone, and prevented by nifedipine. These results show that corticosterone increases Ca²⁺ uptake and starts myofibrillar protein breakdown.<br>

DOI： 10.1271/bbb.67.244

Scopus

PubMed

出版者・発行元：Animal Science Journal  

DOI： 10.1046/j.1344-3941.2003.00082.x

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出版者・発行元：一般財団法人 学会誌刊行センター  

The actions of the thyroid hormone (T₃) are modified by other hormones. Therefore, in the normal cell culture system, with serum as a medium ingredient, it is difficult to eliminate the influences of other hormones derived from the serum. In the present study, two experiments were conducted to clarify the effects of T₃ on differentiation, growth and proteolysis (experiment 1), and concerted effects of T3 and insulin (experiment 2) in a serum-free culture with the use of muscle cells originated from chick embryo. Protein content and creatine kinase (CK) activity were examined as indices of growth and differentia-tion of the muscle cells, respectively, and Nz-methylhistidine (MeHis) release was examined as an index of myofibrillar proteolysis. It was observed that T₃ suppressed both the muscle differentiation and proteolysis in the serum-free medium (experiment 1), though in our previous experiment they were enhanced by T₃ in the serum-supplemented normal medium. On the other hand, T₃ increased myofibrillar proteolysis and had no effect on muscle differentiation when insulin was included in the serum-free medium (experiment 2). These results clearly show that the effects of thyroid hormones on muscle differentiation and proteolysis are apparently different when serum is deprived from the medium, and these differential effects of thyroid hormone could be partially explained by an interaction with insulin, one of the growth factors in the serum.

DOI： 10.3177/jnsv.48.265

Scopus

PubMed

出版者・発行元：Japan Poultry Science Association  

出版者・発行元：Japan Poultry Science Association  

出版者・発行元：一般財団法人 学会誌刊行センター  

The present experiment was conducted to study the effects of dietary vitamin E on plasma corticosterone (CTC) concentration and adrenal steroid syntheses in chickens treated with adrenocorticotropic hormone (ACTH). Chickens were divided into ACTH (-) and ACTH (+) groups, and each group was further divided into three subgroups adminis-tered with vitamin E (500 or 5, 000 mg/kg diet) and without the vitamin. Vitamin E (DL-&alpha;-tocopheryl acetate) was mixed with the basal diet at levels of 500 and 5, 000 mg/kg and fed for 6 d. ACTH (20 IU/kg body weight) was given daily by intraperitoneal injection for 5 d. &alpha;-Tocopherol levels in the plasma and adrenal gland were markedly elevated by vitamin E feeding, and the level of adrenal free cholesterol (CHOL), which is used for steroid synthesis, was significantly decreased by vitamin E feeding in a dose-dependent manner. However, the level of adrenal CHOL ester was unchanged by any treatment. The elevations of preg-nenolone, progesterone and CTC levels in the adrenal gland of chickens with ACTH treat-ment were decreased by vitamin E administration. The elevation of plasma CTC concentra-tion in the ACTH (+) group was dramatically decreased by vitamin E administration, while that concentration was not influenced by the vitamin administration in the ACTH (-) group. These findings indicate that vitamin E suppresses the elevation of the plasma CTC concentration due to ACTH in chickens, possibly by inhibiting the conversion of CHOL ester to free CHOL in the adrenal gland.

DOI： 10.3177/jnsv.47.40

Scopus

出版者・発行元：社団法人日本農芸化学会  

&nbsp;&nbsp;We examined the effects of a glucocorticoid, corticosterone, on calpain activity, connectin content and protein breakdown in rat muscle. The results indicated that calpain activity was increased by corticosterone and thus breakdown of connectin was stimulated followed by increased breakdown of skeletal muscle protein.<br>

DOI： 10.1271/bbb.64.2686

Scopus

出版者・発行元：British Journal of Nutrition  

DOI： 10.1017/s0007114500002087

Scopus

出版者・発行元：日本畜産学会  

出版者・発行元：Biochemical and Biophysical Research Communications  

DOI： 10.1006/bbrc.1998.9483

Scopus

出版者・発行元：社団法人日本農芸化学会  

&nbsp;&nbsp;Six-day-old chick skeletal muscle (extensor digitorum longus) was incubated in the presence of corticosterone (CTC; 0, 3, 30, and 300 ng/ml) for 2 h at 37&deg;C. Tyrosine and N^&tau;-methylhistidine releases, as indices of total muscle and myofibrillar proteolysis, were increased by CTC but with different dose responses, indicating an independent regulation of myofibrillar and non-myofibrillar protein degradation.<br>

DOI： 10.1271/bbb.62.1781

Scopus

出版者・発行元：一般財団法人 学会誌刊行センター  

The purpose of this study was to investigate the effect of vitamin E on oxidative stress in the skeletal muscle of glucocorticoid-treated rats. Male Sprague-Dawley rats (5 weeks of age) were fed a basal diet or a diet supplemented with vitamin E (5, 000 mg DL-&alpha;-tocopheryl acetate/kg diet) for 10 d. The rats of both diet groups received subcutaneous injections of corticosterone (CTC) (0, 25, and 100mg/kg body weight/d) during the final 4d. Weights of the extensor digitorum longus and gastrocnemius (CAST) muscles were dose-dependently reduced by CTC. However, the muscle weight losses in rats fed the vitamin E diet were smaller than those in rats fed the basal diet. Protein carbonyl content in the GAST muscle, which was determined as an index of oxidatively modified protein, was increased by 100mg of CTC, and the increment was significantly (<i>p</i><0.01) reduced by vitamin E supplement. Hypergly-cemia was induced by 100mg of CTC, but it was not affected by vitamin E. Lipid peroxide (TBARS) in plasma and in GAST muscle was elevated by 100mg of CTC, and vitamin E significantly (<i>p</i><0.001) suppressed the formation of TBARS in the muscle. The change in TBARS paralleled that in protein carbonyl. These results show that CTC leads to oxidative stress in rat skeletal muscles and that vitamin E has roles in reducing the oxidative stress which causes muscle atrophy.

DOI： 10.3177/jnsv.44.779

Scopus

出版者・発行元：Journal of Nutritional Science and Vitaminology  

DOI： 10.3177/jnsv.44.237

Scopus

出版者・発行元：一般財団法人 学会誌刊行センター  

The effects of thyroxine (T₄) and triiodothyronine (T₃) on growth, muscle protein degradation, and proteases activities in cultured chick muscle cells were studied. The cells were treated with a physiological level of T₄ (60ng/mL) or T₃ (12ng/mL) for 6d. Calpain, cathepsins, and proteasome activities and <i>N</i>^&tau;-methylhistidine release were measured as indexes of myofibrillar protein breakdown. Creatine kinase activity was also measured as an index of myotube formation. Calpain activity was increased by T₄ and T₃. Cathepsin D and proteasome activities and <i>N</i>^&tau;-methylhistidine release were increased by T₃, but not by T₄. Neither were cathepsin B and B+L activities affected by T₃ or T₄. Creatine kinase activity was increased by T₄ and T₃. The results suggest that myotube formation is accelerated by T₄ and T₃, whereas myofibrillar protein degradation is accelerated by T₃, but not by T₄.

DOI： 10.3177/jnsv.44.799

Scopus

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