Application of the CI component to enrich marketable eggs with iodine

The composition of iodized milk proteins containing iodotyrosines has iodine covalently bonded to the carbon atom. The authors proposed a term “CI” for it, which denotes a promising source of safe “organic” iodine in feedstuff for poultry. The aim of using this component is production of a functional product enriched with bonded iodine, namely, marketable eggs. The paper presents investigations of an effect of bonded iodine (CI component) included in the feedstuff for laying hens on the content of total iodine and iodotyrosines in eggs as well as on the balance of intake and accumulation of iodine in eggs. The experiment was carried out for eight weeks on laying hens of Lohman-lsl-classic cross. Birds of the control group received combined feed containing iodine in the form of calcium iodate on the basis of 1 mg/kg feed during the whole experiment. The hens of the experimental group received the CI component in addition to the basic diet. From the 1st to the 28th day, an amount of iodine added to the feedstuff of the birds of the experimental group in the composition of iodized milk proteins (IMP) was 0.5 mg/kg feed, and from the 29th to the 56th day it was 0.7 mg/kg feed. The content of total iodine was determined in egg yolk and white by inductively coupled plasma mass spectrometry, amounts of mono- and di-iodotyrosines by highperformance liquid chromatography with mass spectrometry detection. It has been found that inclusion of IMP containing the CI component into the diet of laying hens allows obtaining eggs with a high content (50–74 µg/egg) of iodine, which was significantly higher than the values in the control (14.99 µg/egg). Iodine in eggs was mainly (75%) in bonded, “organic” form as mono- and di-iodotyrosines. A level of iodine assimilation upon its entry into the bird’s body in a form of iodotyrosines was 25–32%, which is significantly higher than this indicator when the inorganic iodine form was used (11%). An absence of side effects for birds and improvement of their health, first of all, the reproduction system was noticed. The experiment on laying hen watering using water enriched with mono- and di-iodotyrosines also showed a positive effect in terms of accumulation of iodine in eggs. The experiment on assessment of preservation of mono- and di-iodotyrosines in eggs after heat treatment supported their high stability to an effect of high temperatures. A degree of preservation was 91%.