Papers by Charlotte Rehfeldt
3 Manipulation of Muscle Fibre Number During Prenatal Development Neil C. Stickland, 1Stephanie B... more 3 Manipulation of Muscle Fibre Number During Prenatal Development Neil C. Stickland, 1Stephanie Bayol, 1 Clare Ashton1 and ... TE, Owsley, WF, Rahe, CH and Mulvaney, DR.(1995) Maternal treatment with somatotrophin alters embryonic development and early postnatal ...
British Poultry Science, 1997
1. Male and female broiler chickens (144 in total) were given diets supplemented with clenbuterol... more 1. Male and female broiler chickens (144 in total) were given diets supplemented with clenbuterol (CB) at 0 (control) and at 1 mg/kg between 28 and 49 d of age to study the effect of CB on growth, carcase and skeletal muscle. 2. CB improved growth in males by increasing daily weight gain and final live weight and by lowering food conversion ratio. In females it changed the carcase composition by reducing abdominal fat pad and by increasing the proportion of protein. Consequently, carcase protein gain was increased in both sexes (11% and 16%, respectively). 3. Skeletal muscle weights were enhanced by between 6% and 22%. Muscle fibre diameters were increased in extensor hallucis longus (EHL) but not in gastrocnemius (GAS) muscle. This increase was more pronounced in females. EHL total muscle fibre number remained unchanged. The proportion of fast-twitch glycolytic fibres was increased at the expense of fast-twitch oxidative fibres in males only. Nuclear/cytoplasm and DNA/protein ratios tended to be decreased by CB. 4. From the elevated EHL muscle RNA/DNA, unchanged protein/RNA and translation activity it is suggested that CB stimulated protein synthesis at the pretranslational level. Reduced protein degradation is deduced from decreased neutral calcium-dependent proteolytic activity. 5. It is concluded that broiler chickens respond to long-term CB treatment as has been shown in various mammals. However, the sex-specific response in growth, carcase composition and skeletal muscle cellularity is more clearly apparent in broiler chickens.
Analytical Biochemistry, 1997
The role of estrogens and estrogen-like compounds, such as dietary phytoestrogens, in pig skeleta... more The role of estrogens and estrogen-like compounds, such as dietary phytoestrogens, in pig skeletal muscle growth is largely unknown. The aim of this study was therefore to investigate the in vitro effects of estrogens and isoflavones on porcine muscle satellite cell growth. Myogenic cells were derived from M. semimembranosus of newborn piglets, typified for muscle cell specific proteins (e.g. desmin) and grown in culture. The effects of different concentrations of 17ß-estradiol (0.1 nM; 1 nM; 1µM), estrone (1 nM; 1µM), and of genistein and daidzein (0.1; 1; 10; 100 µM) on DNA synthesis measured as 6 h-(³H)thymidine incorporation were determined in serum-free growth medium. After 7 h (1+6 h) exposure both 17ß-estradiol and estrone slightly decreased DNA synthesis (-4 to -7%). Slight decreases were also observed in response to 1 and 10 µM genistein (-5; -10%) and to 1, 10, and 100 µM daidzein (-3 to -13%), whereas 100 µM genistein (-74%) substantially lowered DNA synthesis. Decreases ...
Isoflavones, which are compounds of soy-based diets, have been reported to be specific inhibitors... more Isoflavones, which are compounds of soy-based diets, have been reported to be specific inhibitors of protein tyrosine kinases that catalyze protein phosphorylation and play an important role in growth factor related signal transduction. Among others, the type 1 insulin-like growth factor receptor (IGF-1-R) and the epidermal growth factor receptor (EGF-R) act as protein tyrosine kinases and therefore could be negatively
Central European Journal of Biology, 2006
A unique set of seven mouse lines, long-term selected for high growth, from different laboratorie... more A unique set of seven mouse lines, long-term selected for high growth, from different laboratories around the world has been comprehensively compared to evaluate these resources for future QTL and gene mapping for growth traits. The heaviest line (DUH) was 40% (males) to 44% (females) heavier than the smallest line (ROH) at birth, and 105% (males) to 114% (females) heavier at 98 d. Body conformation (body length and width, body areas), body composition (dry matter, fat, fatty acid composition, organ weights), and skeletal muscle cellularity also differed substantially. DUH was more than 20% longer (12.3 cm) compared to the shortest line ROH (9.7 cm). DAH (22.5%) had the highest percentage of gonadal fat and the leanest was BEH (7.7%). Line BEH (0.49 g) showed the highest weight for the left M. rectus femoris, which was 2.1 times higher, compared to ROH (0.23 g). These results suggest that different alleles, and possibly different physiological pathways, have contributed to the selection response in the different lines. Therefore these selection lines are an important tool with which to identify the genetic and physiological basis of growth as they may contain many, if not all, growth promoting alleles.
Developments in biologicals, 2008
Splay leg is a hereditary syndrome observed in highly varying frequency in newborn piglets. Altho... more Splay leg is a hereditary syndrome observed in highly varying frequency in newborn piglets. Although the phenotype indicates a muscular weakness, the etiology is still poorly understood. Only recently, the gene expression of muscle atrophy F-box (MAFbx; FBXO32) was proposed as being of diagnostic value for splay leg in piglet. In this study, total RNA from three healthy and three affected male piglets was isolated. Samples were collected from M. gracilis, Mm. adductores, and M. sartorius. Further samples were taken for histological and biochemical analyses. Expression of MAFbx was analysed by real-time RT-PCR and with the GeneChip" Porcine Genome Array (Affymetrix). No significant differences (p>0.05) were observed in relative MAFbx expression, either between the three muscles or between splay leg and healthy piglets for each muscle. The expression of further atrophy-related genes was unchanged, indicating that splay leg is not characterized by general muscular atrophy in th...
Cell and Tissue Research, 2001
The effects of maternal treatment with somatotropin during early gestation on fetal muscle develo... more The effects of maternal treatment with somatotropin during early gestation on fetal muscle development were determined. Crossbred gilts received daily injections of either 3 ml of a placebo (n=31) or of 6 mg porcine somatotropin (n=31) from day (d) 10 to 27 of gestation and samples were collected from d 28 embryos, d 37 and 62 fetuses, and from neonates.
To study the impact of maternal low and high protein intake on carcass and meat quality of the of... more To study the impact of maternal low and high protein intake on carcass and meat quality of the offspring, 40 pregnant German Landrace gilts were fed iso-energetic diets (11.6 MJ ME/kg DM) with high (HP, 30%; n=14), low (LP, 6%; n=14) or control protein (CP, 12%; n=12) levels throughout gestation. Birth weight was lower in LP and HP compared with
The objective of this study was to deter- mine the effects of maternal treatment with porcine som... more The objective of this study was to deter- mine the effects of maternal treatment with porcine somatotropin (pST) during early gestation on embry- onic survival, fetal development, and internal environ- ment for fetal growth. Sixty-two crossbred gilts received daily injections of either 3 mL of a placebo (control, n = 31) or 6 mg of pST (n = 31) from
Salivary proteins may help to prevent enamel abrasion and adverse chemical effects on teeth of he... more Salivary proteins may help to prevent enamel abrasion and adverse chemical effects on teeth of herbivorous mammals. To detect potential candidates for protecting proteins, bovine and goat whole saliva were incubated with dental enamel and glass powder. Salivary proteins, bound to dental enamel and glass, were analysed by SDS-PAGE. Two distinct salivary proteins were found to adhere to bovine enamel
British Journal of Nutrition, 2012
A high protein-low-carbohydrate diet during pregnancy can cause intra-uterine growth restriction.... more A high protein-low-carbohydrate diet during pregnancy can cause intra-uterine growth restriction. However, its impact during pregnancy on maternal, umbilical and fetal plasma amino acid (AA) profiles is unknown. A maternal high-protein (30 %)-low-carbohydrate (HP-LC) diet was compared with isoenergetic standard (12·1 % crude protein; ST) and low-protein (6·5 %)-high-carbohydrate (LP-HC) diets fed to nulliparous pregnant sows to examine changes in AA concentrations in maternal, venous and arterial umbilical and fetal plasma in mid and late pregnancy. At 64 and 94 days of pregnancy (dp), sows underwent Caesarean section, and maternal, umbilical and fetal plasma samples were collected. The HP-LC diet mainly affected maternal plasma AA concentrations. Plasma concentrations of Ile and Val were increased and those of Ala, Glu and Gly were decreased (P ≤ 0·05) in HP-LC compared with ST sows at 64 and 94 dp. The LP-HC diet decreased fetal plasma Glu concentration compared with the ST diet at 94 dp. Substantial AA catabolism was reflected by increased (P ≤ 0·05) maternal and fetal plasma urea concentrations with the HP-LC compared with the ST and LP-HC diets at 94 dp. Fractional placental extraction of Val was higher whereas those of Ala, Gln and Glu were lower in the HP-LC compared with the ST sows at 64 and 94 dp (P ≤ 0·05). Reduced fetal mass at 94 dp was accompanied by reduced fetal extraction of Lys and Pro in the HP-LC group (P ≤ 0·05). In conclusion, a maternal HP-LC diet during pregnancy altered maternal plasma composition of many AA and modified placental AA extraction to compensate for imbalanced maternal nutrient intake.
Pediatric Research, 2008
Soy-based formulas are consumed by growing numbers of infants and used as regular food supplement... more Soy-based formulas are consumed by growing numbers of infants and used as regular food supplements in livestock production. Moreover, constituent dietary phytoestrogens may compete with endogenous estrogens and affect individual growth. This study aimed to investigate the in vitro effects of isoflavones in comparison with estrogens on the proliferation of porcine satellite cells derived from neonatal muscle. After 7 h of exposure in serumfree medium, 17-estradiol (1 nM, 1 M), estrone (1 M), and daidzein (1, 100 M) slightly decreased whereas 100 M genistein substantially lowered DNA synthesis. Declines in DNA amount were observed with genistein (1, 100 M) and daidzein (100 M). After 26 h of exposure, 100 M genistein reduced DNA synthesis, whereas it was increased by 10 M genistein and 10 and 100 M daidzein. In the case of 10 M genistein and 100 M daidzein, these increases apparently resulted from the repair of damaged DNA. Genistein and daidzein (100 M) reduced protein synthesis, caused a G 2 /M phase block, and decreased DNA amount in association with higher rates of cell death partially resulting from apoptosis. Conclusively, isoflavones at concentrations of greater than 1 M act as inhibitors of porcine skeletal muscle cell proliferation. (Pediatr Res 63: 39-45,
Livestock Science, 2008
This study was conducted to investigate the impact of domestication of the pig on various cellula... more This study was conducted to investigate the impact of domestication of the pig on various cellular properties of skeletal muscle. For this purpose, samples of semitendinosus (ST), psoas major (PM), and longissimus (LD) muscles of 24 European wild boars (WB; Sus scrofa scrofa) and of 28 domestic pigs (Sus scrofa domestica) of German Landrace (DP) were taken at birth, and
Livestock Production Science, 2004
The effects of maternal treatment with porcine somatotropin (pST) during early gestation on offsp... more The effects of maternal treatment with porcine somatotropin (pST) during early gestation on offspring growth, carcass quality, and immunological characteristics were determined. Thirty-two sows received daily injections of either a placebo (n=16) or 6 mg of pST (n=16) from day 10 to 27 of gestation with gradual withdrawal until day 37. In neonatal piglets, a birth weight group (BWG) by
Livestock Production Science, 2000
The major component of a given muscle is the constituent muscle fibres. Lean growth and ultimate ... more The major component of a given muscle is the constituent muscle fibres. Lean growth and ultimate muscle mass are therefore largely determined by the number of muscle fibres and the size of those fibres. During myogenesis, myoblasts develop from mesenchymal precursor cells by proliferation and myogenic commitment. Myoblasts subsequently fuse to form multinucleated myofibres. Postnatal growth of skeletal muscle is
Livestock Production Science, 2004
In Charolais (CH) as beef and German Holstein (H) as dairy cattle, differences in concentrations ... more In Charolais (CH) as beef and German Holstein (H) as dairy cattle, differences in concentrations of hormones regulating partitioning of nutrients, are expected. Charolais (n = 13) and Holstein (n = 12) bulls 9 months of age were fed every 4 h. Blood samples were taken every 20 min over 6 h. The average plasma concentration of growth hormone (GH) did not differ, but differences in pulse frequency (CH 4.7 pulses/6 h, S.D. 0.9; H 3.5 pulses/6 h, S.D. 1.2, P = 0.011) and amplitude were observed (CH 6.3 ng/ml, S.D. 2.8; H 10.1 ng/ml, S.D. 4.7, P = 0.026). Plasma concentrations of insulin, glucagon, and leptin also differed (insulin: CH 18.7 AU/ml, S.E. 1.7; H 28.1 AU/ml, S.E. 1.7, P < 0.001; glucagon: CH 82.3 pg/ml, S.E. 7.5; H 120.8 pg/ml, S.E. 7.8, P = 0.002; leptin: CH 2.4 ng/ml, S.E. 0.2; H 3.0 ng/ml, S.E. 0.2, P = 0.008). Insulin and glucagon data were fitted to sinusoidal curves to analyse ultradian rhythm. Differences in amplitude, but not in period, were found. The results suggest that different utilization of nutrients leads to pronounced protein synthesis in CH and elevated fat synthesis in H to meet the episodic energetic demands during lactation in this breed. The results are confirmed by the analysis of selected metabolites. D
Journal of Muscle Research and Cell Motility, 2007
Striated muscles exhibit a wide range of metabolic activity levels. Heart and diaphragm are muscl... more Striated muscles exhibit a wide range of metabolic activity levels. Heart and diaphragm are muscles with continuous contractile performance, which requires life-long function. In contrast, skeletal muscles like longissimus muscle can adapt metabolism from resting to different stages of exercise. The aim of this study was to compare the morphological features of these three muscles and the expression of genes that are important for energy metabolism. Therefore, histochemical studies were performed for determination of muscle fibre type composition. Oxidative and glycolytic capacity was assessed by measuring isocitrate dehydrogenase (ICDH) and lactate dehydrogenase (LDH) activities. The mRNA expression of glucose transporter 4 (GLUT 4), growth hormone receptor (GHR) and AMP-activated kinase (AMPK) alpha(1) and alpha(2) subunits was studied by semiquantitative Northern blotting. Heart, and to a slightly lesser extent diaphragm were highly oxidative muscles characterised by high expression of oxidative muscle fibres and ICDH activity. Longissimus muscle exhibited the highest percentage of glycolytic fibres and LDH activity. GLUT 4 mRNA was lowest in heart reflecting the dependency of heart muscle on fatty acids as major energy source. Higher expression of GLUT 4 in diaphragm indicated that glucose is an important energy substrate in this oxidative muscle. Highest GLUT 4 expression in longissimus should be essential for the refilling of glycogen stores after exercise. AMPK subunits, which are important stimulators of GLUT 4 protein insertion into the sarcolemma, are also highest expressed in longissimus muscle indicating the strong capacity to adapt energy metabolism to large changes in energy demand. Interestingly, AMPK alpha(1) subunit expression on protein level is strongly restricted to muscle fibres containing type I myosin in this muscle. GHR mRNA expression was also highest in longissimus muscle indicating that an enhanced effect of growth hormone, which is described to be diabetogenic, could be involved in the lower insulin sensitivity of glycolytic muscles.
Journal of Muscle Research and Cell Motility, 2005
The murine myostatin mutation Mstn(Cmpt-dl1Abc) (Compact; C) was introduced into an inbred mouse ... more The murine myostatin mutation Mstn(Cmpt-dl1Abc) (Compact; C) was introduced into an inbred mouse line with extreme growth (DUHi) by marker-assisted introgression. To study the allelic effects on muscle fibre hyperplasia and hypertrophy, myonuclear proliferation, protein accretion, capillary density, and muscle fibre metabolism, samples from M. rectus femoris (RF) and M. longissimus dorsi (LD) muscles of animals wild-type (+/+), heterozygous (C/+), and homozygous (C/C) for the Mstn(Cmpt-dl1Abc) allele were examined by histological and biochemical analyses. Homozygous C/C mice exhibited lower body (-12%) but higher muscle weights (+38%) than ++ mice. Total muscle fibre number was increased (+24%), whereas fibre size was not significantly affected. Protein and DNA concentrations and DNA:protein ratios as well as specific CK activity remained unchanged for higher mass muscle implying increases in the total contents of DNA and muscle specific protein. Fibre type distribution was markedly shifted to the white glycolytic muscle fibres (+16-17% units) at the expense of red oxidative fibres. Capillary density was substantially lower in C/C than in ++ mice as seen by lower number of capillaries per fibre (-35%) and larger fibre area per capillary (+77%). However, the Mstn(Cmpt-dl1Abc) allele was partially recessive in heterozygous C/+ mice for both fibre type frequencies and capillary density. The results show that hypermuscularity caused by mutations in the myostatin gene results from muscle fibre hyperplasia rather than hypertrophy, and from balanced increases in myonuclear proliferation and protein accretion. However, capillary supply is adversely affected and muscle metabolism shifted towards glycolysis, which could have negative consequences for physical fitness.
Journal of Muscle Research and Cell Motility, 2000
Myogenic cells were derived from mice long-term selected over 70 generations for high 6-weeks bod... more Myogenic cells were derived from mice long-term selected over 70 generations for high 6-weeks body weight (DU-6) and from unselected control mice (DU-Ks). The cells were grown in medium with 10% foetal bovine serum (FBS) for 8 days or transferred to low serum conditions (1% FBS) at days 4 and 6 of cultivation, respectively, and maintained for two further days. In both cell lines, serum reduction induced decreases in DNA and protein contents, and in DNA synthesis rate. It also triggered apoptotic cell death as demonstrated by increased DNA strand breaks and expression of active caspase-3. Concomitantly, the anti-apoptotic protein bcl-2 was enhanced. The basal frequency of apoptotic cells decreased with time of cultivation in both lines and was lower in DU-6 than in DU-Ks cells. However, the increase in apoptosis induced by serum reduction was more pronounced in DU-6 than in DU-Ks cells and did not differ between the time points of serum reduction. The results suggest that growth selection decreases the basal apoptosis frequency of muscle satellite cells under normal supply, but enhances the intrinsic susceptibility to growth factor withdrawal by serum deprivation as a severe apoptotic stimulus. Furthermore, the apoptotic response to growth factor withdrawal seems to be largely independent of the stage of myogenic development.
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Papers by Charlotte Rehfeldt