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2. Drying procedure and collection time significantly influenced the determined energy and nitrogen concentrations of the excreta.
3. Drying excreta in an oven at 60 °G proved at least as effective as freeze drying for the majority of amino acids. 相似文献
2. Body weight at 169 d of age varied from, on average, 1409 g (15 °C, ad libitum) to 943 g (30 °C, 70% schedule) for the white strain and 1947 to 1250 g for the same treatments respectively for the brown strain. Sexual maturity was considerably delayed by the 70% feeding schedule, only slightly by rearing at 30 °C.
3. Rearing at 30 °C tended to depress subsequent egg output. The 70% feeding schedule at least maintained egg output compared with birds fed ad libitum in rearing.
4. There was a highly significant effect of temperature treatment during lay on food intake. The reduction in food intake due to the 21–28 °C cycle, however, appeared small. 相似文献
2. The tendency was for the proteolytic activity to be increased and the amylase activity to be decreased in conventional chicks. These differences were statistically significant in the caecum.
3. All of the additional proteolytic activity detectable in the caecum of conventional chicks was inhibited by soyabean trypsin inhibitor. However, the increased activity was not detectable in the small intestine and was, therefore, not due to pancreatic trypsin.
4. Attempts to demonstrate in vitro bacterial production of a trypsin‐like enzyme were unsuccessful. 相似文献
2. Contraction of warm eggs in ice‐cold colloidal iron caused flooding of pore canals and contamination of the underlying shell membranes with this element.
3. Appreciable contamination of the inner shell membrane with iron persisted for 25 d in infertile eggs stored at 37.5 °C. 相似文献
2. Resonances from adenosine triphosphate, phosphocreatine, inorganic phosphate and phosphorous storage protein were observed. These changed in relative intensity as the embryo developed.
3. No ill effects due to exposure to radiofrequency radiation or magnetic fields were observed.
4. It is concluded that topical magnetic resonance can make a useful contribution to the study of embryonic development in avian eggs. 相似文献
2. — The first eggs laid are of low weight and shell porosity but generally by the fifth week of lay both characteristics have increased to the values found in the mature flock.
3. —For mature flocks porosity decreases in the summer and the consequences of this are considered in relation to the observed decrease in hatch‐ability at this time. 相似文献
2. Lauryl sulphate at 2.5 g/kg or more in the diet significantly increased shell breaking strength, shell thickness and shell weight at 24 and 36 weeks. In 48‐week‐old hens only shell breaking strength was increased significantly. Egg production and egg weight were not affected significantly by lauryl sulphate.
3. Lauryl sulphate might increase these measures of quality by increasing shell deposition and/or shell elasticity. 相似文献