| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1988: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1987: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
Whole-body protein turnover rates were measured in chicks fed control, histidine-free (-His), and methionine plus cystine-free (-Met, Cys) diets. In chicks fed the amino acid-devoid diets, the fractional synthesis rates of protein (FSR, percent per day) were significantly lower than those in control chicks, whereas fractional degradation rates of protein (percent per day) sere constant for all dietary treatments. The FSR in -Met, Cys chicks was lower than that in -His chicks and the lower FSR in -Met, Cys chicks seemed to result in more body protein loss. The RNA/protein ratio of chicks was almost the same in all treatments, but the protein synthesized per unit RNA varied depending on the dietary treatments. The lower amount of protein synthesized per unit RNA in -Met, Cys chicks was postulated to result from inhibition of protein synthesis by a shortage of available methionine associated with a higher degradation rate of methionine itself. These results indicated that different growth responses between -His and -Met, Cys chicks were primarily caused by the difference in the rate of protein synthesis. Metabolic fate of histidine and methionine was investigated in -His, -Met, Cys and control chicks. Histidine was essentially subjected to slower degradation compared with methionine, and its degradation was further depressed by histidine deficiency and thus spared more in the body, but in the methionine plus cystine deficiency, methionine was degraded at a similar rate as the control. The effect of dietary deficiency of methionine or lysine on protein synthesis was investigated in laying hens. Whole body protein synthesis of laying hens fed amino acid deficient diets was significantly lower than that of control hens. Protein synthesis in the liver, magnum and remainder oviduct was remarkably decreased by dietary deficiency ot these amino acids with larger rate of decrease than those in the whole body.
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