Effect of dietary lysine level on the plasma free lysine concentration of laying hens
Narita, T.; Kondo, F.
Journal of the Faculty of Agriculture Iwate University 13(1): 129-136
The effect of dietary lysine level on the plasma free lysine (PFL) concentration of laying hens was investigated. PFL concentration was measured by a modified Albanese's method using circular filter paper chromatography. After 16 h fasting, the laying hens were fed commercial ration for 1h ad lib. Immediately before (T0) and 1 (T1), 2 (T2), 3 (T3) and 4 (T4) h after feeding, PFL concentration was measured, and .DELTA.PFL was calculated. .DELTA.PFL at T1 was highest and was decreased thereafter. PFL at T1 of laying hens after 24 h fasting was larger than that of laying hens after 16 h fasting. .DELTA.PFL at T1 was good correlated with dietary lysine level. From the regression line obtained, the dietary lysine level at .DELTA.PFL = 0 was estimated as 0.38%. These results suggested that the method described above may be useful to estimate the lysine requirement of laying hens.