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

Abstract

An experiment was conducted to determine the distribution of nitrogen-15 in tissues of laying hens receiving different levels of 15 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 15 N-CCC inclusion. The hens were individually fed with the 15 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 15 N-CCC diets withdrawal. Samples of blood, liver, heart and meat were collected and their 15 N contents were determined. The δ 15 N excess (δ 15 N-ex) and atom percentage excess in 15 N were calculated. The δ 15 N-ex and atom percentage excess 15 N increased significantly (p<0.05) with increasing levels of 15 N-CCC in diets in all tissues after feeding 15 N-CCC diets for eleven days. The highest concentration of δ 15 N-ex and atom percentage excess 15 N were detected in blood, followed in order by liver, heart and thigh meat. The concentrations reduced significantly (p<0.05) after 15 N-CCC diets were withdrawn. Comparison between treatment groups showed that δ 15 N-ex and atom percentage excess 15 N were still higher in hens that had been fed diets with higher levels of 15 N-CCC. This study showed that nitrogen-15 was distributed in blood, liver, heart and meat of laying hens.