1. Five diets containing different amounts of protein (178, 210, 243, 275, 308 g/kg) were fed to broilers reared at 16, 21, 26 and 31 °G from 27, 21, 11 and 1 d of age, respectively.
2. Feeding the diets with increased concentrations of protein apparently does not reduce the growth rate depression of the broiler reared at 26 or 31 °C. 相似文献
1. Male and female broilers from 21 d of age were fed on either a complete diet or given a choice of whole wheat and one of two higher‐protein foods formulated by omitting some or all of the cereal from the complete diet.
2. For males receiving the choice treatments, on average 44.7 and 73.1 % by weight, respectively of the food consumed from 21 d consisted of whole wheat. The corresponding figures for the females were 49.9 and 77.3% respectively.
3. Growth rate from 21 d was significantly lower for the males which received wheat and the cereal‐free higher‐protein food and for the females on either choice treatment. Differences in the treatment means, however, were small. 相似文献
It is well established that reproductive function is metabolically gated. However, the mechanisms whereby energy stores and metabolic cues influence appetite, energy homeostasis and fertility are yet to be completely understood. Adipose tissue is no longer considered as only a depot to store excess energy. Recent findings have identified numerous genes, several neurotrophic factors, interleukins, insulin-like growth factor binding protein-5, ciliary neurotrophic factor and neuropeptide Y (NPY) as being expressed by adipose tissue during pubertal development. These studies demonstrated for the first time the expression of several major adipokines or cytokines in pig adipose tissue which may influence local and central metabolism and growth. Leptin appears to be the primary metabolic signal and is part of the adipose tissue-hypothalamic regulatory loop in the control of appetite, energy homeostasis and luteinizing hormone (LH) secretion. Leptin's actions on appetite regulation are mediated by inhibition of hypothalamic NPY and stimulation of proopiomelanocortin. Its effects on gonadotropin-releasing hormone (GnRH)/LH secretion are mediated by NPY and kisspeptin. Thus, leptin appears to be an important link between metabolic status, the neuroendocrine axis and subsequent fertility in the gilt and sow. 相似文献
Four dogs were treated for acute toxicity following ingestion of the popular garden shrub 'Yesterday, today, tomorrow' (Brunfelsia spp). Clinical signs included vomiting, diarrhoea, muscle tremors, anxiousness, opisthotonus and seizures. All dogs recovered following treatment with any or all of general anaesthetic, gastric lavage, enema, diazepam, phenobarbitone or propofol sedation. Brunfelsia spp toxicity should be considered in young, previously healthy dogs presenting with gastrointestinal signs that rapidly progress to muscle tremors and seizures. Examination of faeces was required for diagnosis in all cases. Owners should also be questioned thoroughly about their dogs' access to such plants. 相似文献
Data from the Global Oscillation Network Group (GONG) project and other helioseismic experiments provide a test for models of stellar interiors and for the thermodynamic and radiative properties, on which the models depend, of matter under the extreme conditions found in the sun. Current models are in agreement with the helioseismic inferences, which suggests, for example, that the disagreement between the predicted and observed fluxes of neutrinos from the sun is not caused by errors in the models. However, the GONG data reveal subtle errors in the models, such as an excess in sound speed just beneath the convection zone. These discrepancies indicate effects that have so far not been correctly accounted for; for example, it is plausible that the sound-speed differences reflect weak mixing in stellar interiors, of potential importance to the overall evolution of stars and ultimately to estimates of the age of the galaxy based on stellar evolution calculations. 相似文献
Atmospheric general circulation models used for climate simulation and weather forecasting require the fluxes of radiation, heat, water vapor, and momentum across the land-atmosphere interface to be specified. These fluxes are calculated by submodels called land surface parameterizations. Over the last 20 years, these parameterizations have evolved from simple, unrealistic schemes into credible representations of the global soil-vegetation-atmosphere transfer system as advances in plant physiological and hydrological research, advances in satellite data interpretation, and the results of large-scale field experiments have been exploited. Some modern schemes incorporate biogeochemical and ecological knowledge and, when coupled with advanced climate and ocean models, will be capable of modeling the biological and physical responses of the Earth system to global change, for example, increasing atmospheric carbon dioxide. 相似文献