Nitrogen-15 Determination in Tissues of Laying Hens Fed on Different Levels of N-Chlorocholine Chloride (N-CCC) Diets

An experiment was conducted to determine the distribution of nitrogen-15 in tissues of laying hens receiving different levels of N-CCC in diets. Twenty brown laying hens were divided into four groups and randomly assigned into one of four dietary treatment groups consisting of 0, 5, 50 and 100 ppm N-CCC inclusion. The hens were individually fed with the N-CCC diets in battery cages for 11 days and then all hens restored to feeding on the control diet for 7 days. After eleven days, eight hens were slaughtered, and the others were slaughtered seven days after N-CCC diets withdrawal. Samples of blood, liver, heart and meat were collected and their N contents were determined. The δN excess (δN-ex) and atom percentage excess in N were calculated. The δN-ex and atom percentage excess N increased significantly (p<0.05) with increasing levels of N-CCC in diets in all tissues after feeding N-CCC diets for eleven days. The highest concentration of δN-ex and atom percentage excess N were detected in blood, followed in order by liver, heart and thigh meat. The concentrations reduced significantly (p<0.05) after N-CCC diets were withdrawn. Comparison between treatment groups showed that δN-ex and atom percentage excess N were still higher in hens that had been fed diets with higher levels of N-CCC. This study showed that nitrogen-15 was distributed in blood, liver, heart and meat of laying hens. (