The effects of various sources and levels of iodine, as well as type of diet were studied on the performance of young laying hens, iodine accumulation in eggs, egg characteristics and morphotic and biochemical indices in blood by scientists at Wroclaw University of Environmental and Life Sciences in Poland.

Reporting their study in Poultry Science, first-named author, Maja Slupczynska and colleagues explain that over a period of 150 days, young hens were fed with two of diets including corn and soybean meal or corn, soybean and rapeseed meal.

Diets were enriched with potassium iodide (KI) or potassium iodate (KIO3) as an iodine source in amounts equal to 1, 3 or 5mg of supplemented iodine per kg of feed.

Hen performance, egg quality, haematological and morphotic indices in blood, hepatic enzyme activity, lipid indices in blood serum as well as iodine accumulation in wet egg content were determined.

Introduction of double-zero rapeseed meal into the diet improved the laying rate and feed conversion (P<0.05); however, better egg weight was noted by feeding the hens with a diet without rapeseed meal.

Use of KI as the iodine source enhanced the egg weight.

Increased iodine level in the diet had an equivocal influence on egg weight, improved the feed conversion per kilo of eggs and decreased the proportion of damaged eggs.

The use of corn, soybean and rapeseed meal in hen diets significantly improved yolk colour; similar results were noted after an increase in iodine levels in the diets after three months of feeding.

Haematological indices of hen blood demonstrated significantly higher red blood cells numbers and hemoglobin concentrations with the use of KI.

The use of a diet containing rapeseed meal led to an enhancement of hepatic enzyme activity, especially of alkaline phosphatase (P=0.007).

Lipid metabolism indices were not influenced by the kind of diet or the iodine source or level.

The accumulation of iodine in wet egg content was negatively influenced by the use of a diet containing rapeseed meal (P=0.000). The application of KI as an iodine source enhanced (P=0.003) the accretion of iodine in eggs after five months of treatment.

Enhanced iodine supply significantly increased accumulation of iodine in eggs (P=0.000) after three and five months of the experiment from 260 and 310 to 1,011 and 1,256µg per kg of wet egg content, respectively.

Reference

Slupczynska M., D. Jamroz, J. Orda and A. Wiliczkiewicz. 2014. Effect of various sources and levels of iodine, as well as the kind of diet, on the performance of young laying hens, iodine accumulation in eggs, egg characteristics, and morphotic and biochemical indices in blood. Poultry Science. 93(10):2536-2547. doi: 10.3382/ps.2014-03959

October 2014