Publisher：Animal Science Journal  

DOI： 10.1111/asj.13327

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Publisher：John Wiley & Sons Australia, Ltd  

Publisher：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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Publisher：Animal Science Journal  

DOI： 10.1111/asj.13291

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Publisher：General and Comparative Endocrinology  

DOI： 10.1016/j.ygcen.2019.113232

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Publisher：Journal of Thermal Biology  

DOI： 10.1016/j.jtherbio.2019.04.016

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Publisher：Animal Science Journal  

DOI： 10.1111/asj.13141

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：日本暖地畜産学会  

Publisher：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

Publisher：Warm Regional Society of Animal Science, Japan  

<p>Sensory evaluation and physical and chemical analyses were performed using loin meats of Kagoshima Berkshire （BB） pigs, domestic three-way cross（ LWD） pigs, and Canadian-imported LWD（ LWDc） pigs. We compared the results of physical and chemical analyses and their correlations with the results of the sensory evaluation. Both BB and LWD pig meat that received a high evaluation score for "favorite scent" in the sensory evaluation was characterized by many odorous substances. BB pig meat received high evaluation scores for "ease of shearing" and "ease of chewing" in the sensory evaluation. BB pig meat had higher water-holding capacity than LWDc pig meats. The relative concentrations of free glutamic acid, which produces umami taste, and those of threonine, proline, and alanine, all of which produce sweet taste, were significantly high in BB pig meat. In the fatty acid composition of backfat, the percentage of polyunsaturated fatty acids was low in BB pig meat. BB pig meat obtained higher score of overall sensory evaluation than LWD and LWDc pig meats. These results demonstrate that BB pig meat is soft and juicy, rich in taste-related amino acids, and low in polyunsaturated fatty acids and has many odorous substances and high water-holding capacity.</p>

DOI： 10.11461/jwaras.62.17

Publisher：General and Comparative Endocrinology  

DOI： 10.1016/j.ygcen.2018.05.028

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Publisher：Journal of Agricultural and Food Chemistry  

DOI： 10.1021/acs.jafc.8b00853

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Publisher：Zootechnical Science Society of Japan  

<p>The aim of this study was to evaluate the effects of delayed feeding for 2 days post hatching period on lipid peroxidation, drip losses, color, and taste of chicken breast meat. Twelve newly hatched chicks (0 day of age) were randomly divided into two groups (control and delayed feeding group). The control group of chicks was fed <i>ad libitum</i> from 0 day of age, while the delayed feeding group of chicks was fed <i>ad libitum</i> from 2 days of age after fasting for 2 days post hatching. When the chicks reached an average body weight of 2.2kg, they were slaughtered. Although delayed feeding prolonged feeding period for 5 days, body weight gain, feed intake, feed conversion ratio, and carcass yield were not significantly different between these 2 groups. The delayed feeding group of broiler chickens showed increases in drip losses and lipid peroxidation accompanied by decreased mRNA expression of antioxidant enzymes and α-tocopherol concentration in their breast muscle. In addition, meat color of breast muscle was affected by delayed feeding, i.e., redness (a*) of the breast muscle of the delayed feeding group of broiler chickens was decreased, while its lightness (L*) was increased compared with those of the control broiler chickens. The metabolomic analysis of the breast muscle of broiler chickens showed that 12 metabolites, including taste components (e.g., glucose, glycine, and hydroxyproline), were different between the two groups. Furthermore, taste sensor evaluation suggested umami taste in the breast muscle of the delayed feeding group of broiler chickens were lower compared with those of control chickens. These results suggest that delayed feeding for 2 days post hatching period affected lipid peroxidation, drip losses, color, and taste component of breast meat of broiler chickens.</p>

DOI： 10.2508/chikusan.89.191

Publisher：Comparative Biochemistry and Physiology -Part A : Molecular and Integrative Physiology  

DOI： 10.1016/j.cbpa.2017.05.013

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Publisher：Comparative Biochemistry and Physiology -Part A : Molecular and Integrative Physiology  

DOI： 10.1016/j.cbpa.2016.12.014

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Publisher：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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Publisher：Bioscience, Biotechnology and Biochemistry  

DOI： 10.1080/09168451.2017.1383846

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Publisher：The Japanese Society of Swine Science  

<p>In a large-scale survey regarding 46,724 Berkshire pig carcasses and 342,787 other pig carcasses conducted at two slaughterhouses in Kagoshima prefecture, the percentage of top-grade Berkshire pig carcasses (52%) was lower than that of other pig carcasses (60%) because of excessive backfat thickness (Berkshire pig, 28%;other pig, 13%). In the first experiment, the effect of sex (barrow and gilt) on the backfat thickness of Kagoshima Berkshire pigs raised under restricted feeding conditions was investigated. The backfat thickness of barrow carcasses was thicker than that of gilt carcasses. In the second experiment, the effects of the feeding method and sex on carcass evaluation were investigated to establish a management method of controlling the backfat thickness of Kagoshima Berkshire pigs in the late fattening stage on pig farms. Ninety pigs were assigned to three dietary treatment groups:intermittent feeding on a 76% total digestible nutrients (TDN76%) diet (I-T76) from 80 kg of body weight, restricted feeding on a TDN76% diet (R-T76) from 70kg of body weight, and restricted feeding on a TDN70% diet (R-T70) from 70kg of body weight. Each dietary treatment group consisted of three subgroups:barrow (n＝10), gilt (n＝10), and mixed (barrow, n＝5 and gilt, n＝5). In the barrow subgroups, the percentages of lower-grade carcasses due to excessive backfat thickness in the I-T76, R-T76, and R-T70 groups were 80%, 76%, and 50%, respectively. On the other hand, in the mixed subgroups, the percentages of lower-grade carcasses in the I-T76, R-T76, and R-T70 groups were 20%, 10%, and 10%, respectively. In the barrow subgroups, the percentages of top-grade carcasses in the I-T76, R-T76, and R-T70 groups were 20%, 33%, and 50%, respectively. On the other hand, in the mixed subgroups, the percentages of top-grade carcasses in the I-T76, R-T76, and R-T70 groups were 80%, 80%, and 70%, respectively. In all dietary treatment groups, the backfat thickness in the barrow subgroups were significantly thicker than those in the gilt subgroups. In the mixed subgroups, however, there were no differences in the backfat thickness between barrow and gilt. These results suggested that the mixed rearing of barrow and gilt, switching feed as early, and lowering TDN content of the feed for the late fattening stag are effective management methods raising the percentage of top-grade carcass of Kagoshima Berkshires pigs by suppressing excessive backfat thickness.</p>

DOI： 10.5938/youton.54.4_168

Publisher：Animal Science Journal  

DOI： 10.1111/asj.12541

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Publisher：Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology  

DOI： 10.1007/s00360-015-0957-x

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Publisher：Animal Science Journal  

DOI： 10.1111/asj.12437

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Publisher：Bioscience, Biotechnology and Biochemistry  

DOI： 10.1080/09168451.2016.1162088

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Publisher：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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Publisher：Bioscience, Biotechnology and Biochemistry  

DOI： 10.1080/09168451.2016.1158629

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Publisher：Animal Science Journal  

DOI： 10.1111/asj.12281

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Publisher：General and Comparative Endocrinology  

DOI： 10.1016/j.ygcen.2014.12.002

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Publisher：Bioscience, Biotechnology and Biochemistry  

DOI： 10.1080/09168451.2015.1032883

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Publisher：World's Poultry Science Journal  

DOI： 10.1017/S0043933914000907

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Publisher：General and Comparative Endocrinology  

DOI： 10.1016/j.ygcen.2014.07.023

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Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Publisher：Veterinarni Medicina  

DOI： 10.17221/7818-VETMED

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Publisher：Egyptian Journal of Neurology, Psychiatry and Neurosurgery  

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Publisher：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

Language：English   Publishing type：Research paper (scientific journal)  

Publisher：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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Publisher：BioMed Research International  

DOI： 10.1155/2013/594393

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Language：English   Publishing type：Research paper (scientific journal)  

Publisher：General and Comparative Endocrinology  

DOI： 10.1016/j.ygcen.2013.03.007

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Language：Japanese   Publishing type：Research paper (scientific journal)  

Publisher：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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Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publisher：Japan Poultry Science Association  

Language：English   Publishing type：Research paper (scientific journal)  

Publisher：British Journal of Nutrition  

DOI： 10.1017/S0007114511007069

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Publisher：Animal Science Journal  

DOI： 10.1111/j.1740-0929.2011.00999.x

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Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publisher：Japan Poultry Science Association  

Publisher：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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Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Publisher：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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Publisher：Japan Poultry Science Association  

Publisher：Poultry Science  

DOI： 10.3382/ps.2007-00340

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Publisher：Japan Poultry Science Association  

Language：English   Publishing type：Research paper (scientific journal)  

Publisher：Japan Poultry Science Association  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publisher：Animal Science Journal  

DOI： 10.1111/j.1740-0929.2005.00304.x

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Publisher：British Poultry Science  

DOI： 10.1080/00071660500255661

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Publisher：Animal Science Journal  

DOI： 10.1111/j.1740-0929.2005.00293.x

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Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publisher：American Journal of Physiology - Endocrinology and Metabolism  

DOI： 10.1152/ajpendo.00073.2004

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Publisher：Japan Poultry Science Association  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publisher：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

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Publisher：Japan Poultry Science Association  

Publisher：British Poultry Science  

DOI： 10.1080/0007166031000085427

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Publisher：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

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Publisher：Animal Science Journal  

DOI： 10.1046/j.1344-3941.2003.00082.x

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Publisher：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

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Publisher：Japan Poultry Science Association  

Publisher：Japan Poultry Science Association  

Publisher：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

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Publisher：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

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Publisher：British Journal of Nutrition  

DOI： 10.1017/s0007114500002087

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Publisher：日本畜産学会  

Publisher：Biochemical and Biophysical Research Communications  

DOI： 10.1006/bbrc.1998.9483

Scopus

Publisher：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

Publisher：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

Publisher：Journal of Nutritional Science and Vitaminology  

DOI： 10.3177/jnsv.44.237

Scopus

Publisher：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

Event date： 2010.11

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国内学会

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国際学会

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国内学会

Event date： 2009.5

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Venue：長崎県（長崎ブリックホール他）  

国内学会

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国内学会

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国内学会

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国内学会

Event date： 2005.11

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国内学会

Event date： 2005.11

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Venue：長崎シーボルト大学  

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Event date： 2005.11

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Venue：長崎シーボルト大学  

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Event date： 2005.5

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Venue：東京世田谷  

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Event date： 2005.5

Language：Japanese  

Venue：東京世田谷  

国内学会

Event date： 2005.5

Language：Japanese  

Venue：東京世田谷  

国内学会

Event date： 2004.5

Language：Japanese  

Venue：仙台  

国内学会