Performance, incidence of metabolic disturbances and endocrine variables of food-restricted male broiler chickens

1. This experiment was carried out to evaluate the productive and physiological consequences of a slight but long term food restriction of male broiler chickens from 2 commercial strains.2. Cobb-500 and Ross chickens were submitted to a 20% food restriction from 8 to 21 d of age. Strain, food programme and their interactive effects were analysed in terms of consequences upon performance, mortality, incidence of sudden death syndrome (SDS) and ascites syndrome (AS), index of right cardiac hypertrophy and plasma concentrations of hormones related to metabolism and growth (T-3, T-4, T-3:T-4 ratio, IGF-I and GH).3. Although some catch-up growth was observed by refeeding previously restricted birds after 22 d of rearing, food restriction decreased (P less than or equal to 0.05) body weight at market age (42 d) irrespective of the strain, but improved (P less than or equal to 0.05) food conversion.4. The incidence of mortality was not high in non-restricted birds but SDS and AS caused more than 50% of deaths. Hypertrophic cardiac index was observed in chickens of both strains after 4 weeks of age and was higher in ad libitum fed birds.5. During the period of food restriction, plasma T-3 and IGF-I concentrations decreased whereas plasma T-4 and GH concentrations increased compared to those of the age-matched ad libitum fed counterparts. During the subsequent ad libitum feeding period, few differences in circulating hormone concentrations were observed, except for the higher mean CH litres in previously food-restricted chickens at 35 d of age.6. These results indicate that even a non-severe food restriction negatively affects body weight of 42-d-old male broilers but these are benefits with improved food efficiency and diminished mortality from metabolic disturbances. The hormone results suggest that the degree of food restriction applied was not severe because there was a very fast adaptive response with small and transient alterations in T-3, T-4 and GH plasma concentrations during the period of compensatory growth.

Age-related changes in muscle fiber type frequencies and cross-sectional areas in straightbred and crossbred rabbits

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Targeted Nucleotide Exchange in Bovine Myostatin Gene

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Morphological and histochemical study of the myotomal muscle in pacu (Piaractus mesopotamicus Holmberg, 1887) during the initial growth phases

Morphological and histochemical methods were used to evaluate the myotomal muscle characteristics of pacu (Piaractus mesopotamicus) from hatching to 40 days old. During the larval period, the musculature consisted predominantly of white muscle. White and red muscle mass increased at 10, 20, 30 and 40 days after hatching. The larvae had round muscle fibers with a moderate degree of maturation and central nuclei. In subsequent phases, small and immature fibers were visible near larger and more differentiated fibers. Undifferentiated cells or presumptive myoblasts located in embryogenic zones were visible in the dorsal and ventral regions, and were more evident at 30 and 40 days. The red muscle fibers located in the subdermal region, had oxidative metabolism and slow contraction, whereas the more predominant white muscle fibers had glycolytic metabolism and fast contraction. Our findings indicate that during the initial phases, myotomal muscle growth in pacu occurs by both, muscle fiber hypertrophy and hyperplasia. The analysis of frequency of red and white muscle fibers shows that hyperplastic growth is intense in this period. As the growth rate in adult fish is related to the number of muscle fibers in young fish, extrinsic factors could change the muscle fiber phenotype and influence their ultimate size.

Growth characteristics of skeletal muscle tissue in Oreochromis niloticus larvae fed on a lysine supplemented diet

The effect of lysine amino acid supplementation on the growth characteristics and morphological pattern of skeletal muscle tissue in Nile tilapia Oreochromis niloticus larvae was evaluated. There were four treatments (T) with increasing levels of lysine supplement (T1 = 0.0%: T2 =1.1%; T3 = 1.7%; T4 = 4.0%) and one treatment with a commercial diet (T5). In all treatments, morphological and histochemical muscle tissue analyses were similar. Two distinct layers were identified: a superficial red layer, more developed in the lateral line region, formed by fibres with intense to moderate NADH-TR reaction and strong acid-stable mATPase activity, and a deep white one, most of the Muscle mass, formed by fibres with weak NADH-TR reaction and strong alkali-stable mATPase activity. There was an intermediate layer between these two layers with fibres exhibiting either weak acid-stable or acid-labile mATPase activity. Body mass increase was significantly higher in T5 than in the lysine treatments (T1-T4). There was no difference in number and diameters of muscle fibres between lysine treatments. In T5, muscle fibre diameter and number were higher. The frequency of red fibres with diameters <= 8 mu m was higher in the lysine treatments, and with diameters between 16 and 24 mu m, was higher in T5. Most white fibre diameters in T5 were significantly larger than 24 mu m and in T1-T4 were between 8 and 16 mu m. Cell proliferation was higher in the lysine treatments and muscle growth in T5 was mainly by fibre hypertrophy. (c) 2005 the Fisheries Society of the British

MyoD, myogenin and proliferating cell nuclear antigen expression in growing Nile tilapia (Oreochromis niloticus L.)

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Food restriction impairs myocardial inotropic response to calcium and beta-adrenergic stimulation in spontaneously hypertensive rats

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Differential expression of myogenic regulatory factor MyoD in pacu skeletal muscle (Piaractus mesopotamicus Holmberg 1887: Serrasalminae, Characidae, Teleostei) during juvenile and adult growth phases

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Differential nutritional, endocrine, and cardiovascular effects in obesity-prone and obesity-resistant rats fed standard and hypercaloric diets

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Quantitative expression of myogenic regulatory factors MyoD and myogenin in pacu (Piaractus mesopotamicus) skeletal muscle during growth

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cardiac remodeling in a rat model of diet-induced obesity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Growth hormone attenuates skeletal muscle changes in experimental chronic heart failure

Objective: This study evaluated the effects of growth hormone (GH) on morphology and myogenic regulatory factors (MRF) gene expression in skeletal muscle of rats with ascending aortic stenosis (AAS) induced chronic heart failure.Design: Male 90-100 g Wistar rats were subjected to thoracotomy. AAS was created by placing a stainless-steel clip on the ascending aorta. Twenty five weeks after surgery, rats were treated with daily subcutaneous injections of recombinant human GH (2 mg/kg/day; AAS-GH group) or saline (AAS group) for 14 days. Sham-operated animals served as controls. Left ventricular (LV) function was assessed before and after treatment. IGF-1 serum levels were measured by ELISA. After anesthesia, soleus muscle was frozen in liquid nitrogen. Histological sections were stained with HE and picrosirius red to calculate muscle fiber cross-sectional area and collagen fractional area, respectively. MRF myogenin and MyoD expression was analyzed by reverse transcription PCR.Results: Body weight was similar between groups. AAS and AAS-GH groups presented dilated left atrium, left ventricular (LV) hypertrophy (LV mass index: Control 1.90 +/- 0.15; AAS 3.11 +/- 0.44; AAS-GH 2.94 +/- 0.47 g/kg; p < 0.05 AAS and AAS-GH vs. Control), and reduced LV posterior wall shortening velocity. Soleus muscle fiber area was significantly lower in AAS than in Control and AAS-GH groups; there was no difference between AAS-GH and Control groups. Collagen fractional area was significantly higher in MS than Control; AAS-GH did not differ from both Control and AAS groups. Serum IGF-1 levels decreased in AAS compared to Control. MyoD mRNA was significantly higher in AAS-GH than AAS; there was no difference between AAS-GH and Control groups. Myogenin mRNA levels were similar between groups.Conclusion: In rats with aortic stenosis-induced heart failure, growth hormone administration increases MyoD gene expression above non-treated animal levels, preserves muscular trophism and attenuates interstitial fibrosis. These results suggest that growth hormone may have a potential role as an adjuvant therapy for chronic heart failure. (C) 2009 Elsevier Ltd. All rights reserved.

Anatomia de ápices radiculares de feijão cv. carioca submetidos a níveis de boro em solução nutritiva

Foram estudadas as alterações anatômicas em ápices radiculares do feijoeiro (Phaseolus vulgaris L. cv. Carioca), quando submetidos a diferentes níveis de boro em solução nutritiva. Através de um experimento inteiramente casualizado, foram realizados três tratamentos como se segue: T1 0,50 mg L-1 de boro (testemunha); T2 0,25 mg L-1 de boro (nível intermediário); T0 omisso em boro; sendo feitas amostragens em três estágios sucessivos de desenvolvimento da planta, no decorrer de seu ciclo. As alterações foram avaliadas efetuando-se secções longitudinais de ápices radiculares, sendo analisados comparativamente por meio de estudo cito-histológico com o emprego de microscópio de luz. Considerando como testemunha as plantas submetidas ao nível de 0,50 mg L-1 de boro na solução nutritiva, pôde-se verificar que a omissão desse micronutriente, na solução nutritiva, provocou inibição da divisão e alongamento celular, hipertrofia de células, desorganização de elementos vasculares em raiz, impedindo que a planta completasse seu ciclo, morrendo ao redor do 55o. dia após o transplante. O nível de 0,25 mg L-1 de boro, na solução nutritiva, embora tenha provocado desorganização no ápice radicular, não impediu o desenvolvimento da planta.

Alterações anatômicas induzidas por Meloidogyne enterolobii (=M. mayaguensis) e Meloidogyne javanica em tomateiros resistentes a meloidoginose

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Influence of different doses of retinoic acid on cardiac remodeling

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)