Effects of supplementary iodine on the performance and egg traits of laying hens

Abstract

1. This experiment was carried out to determine the effects of dietary iodine supplementation on the performance and egg traits of laying hens. A total of 600 SHSY type brown layers aged 21 weeks of age were chosen at random from a large flock. They were randomly distributed into 30 pens at 20 hens per pen. Each treatment comprised 6 replicates of 20 layers in groups of 5 birds. The diets were supplemented with 0, 3, 6, 12 and 24 mg/kg iodine as calcium iodate. The experimental period lasted 30 weeks. 2. There were no significant differences among the groups in body weight, food consumption, egg production, food consumption per kg eggs, eggshell index, eggshell breaking strength, shell thickness or egg yolk index. 3. Supplementation of the diet with 12 mg/kg iodine increased food consumption per dozen eggs compared to the groups fed on diets supplemented with 0 and 6 mg/kg iodine. 4. Egg weight was less in groups fed on diets supplemented with 12 and 24 mg/kg iodine than in the group receiving no iodine supplementation. 5. Iodine supplementation to provide 12 and 24 mg/kg reduced egg albumen index and egg Haugh units. 6. There were no significant differences among the groups in egg cholesterol and egg yolk cholesterol contents. 7. The iodine concentrations in egg yolk, egg albumen and whole egg increased with increased iodine supplementation. 8. As a result, the 3 and 6 mg/kg iodine supplementation of diet could be used to enrich the eggs with iodine without any adverse effect on performance and egg traits.

The effects of dietary calcium iodate on productive performance, egg quality and iodine accumulation in eggs of laying hens

“…In agreement with the present study, some researchers reported that I supplementation to layer hens diets had no significant effects on egg production, egg mass production, egg weight, feed intake, FCR, un‐normal eggs and body weight changes (Lichovnikova & Zeman, ; Opaliński et al., ; Yalçin, Kahraman, Yalcin, Yalcin, & Dedeoglu, ).…”

The effects of iodine level and source on iodine carry-over in eggs and body tissues of laying hens

“…The tested concentrations showed no significant impact on hen performance (Tables 3 and 5), which confirmed other studies (Richter 1995;Yalc¸in et al 2004). However, potential long-term effects, as found by and Lichovnikova et al (2003), were not tested in the present study.…”

Opinion of the Scientific Panel on additives and products or substances used in animal feed (FEEDAP) on the use of iodine in feedingstuffs

“…Iodine contents of 0.8, 2.9, 5.2, 11.1 and 21.5 mg kg -1 layer diet resulted in 48, 107, 180, 290 and 511 µg iodine kg -1 egg albumen, and 443,664,1122,1953 and 3352 µg iodine kg -1 egg yolk, respectively (Yalçin et al, 2004).…”

“…Iodine from eggs is calculated based on the data of Yalçin et al (2004). For layer diets containing 10 mg iodine kg -1 , the experimental data obtained with 11.1 mg iodine kg -1 are used, for 5 mg iodine kg -1 , the data obtained at 5.2 mg iodine kg -1 .…”

“…Peterson (1997) described fertility disturbances in laying hens receiving a diet containing 40 mg iodine kg -1 . A recent study (Yalçin et al, 2004) conducted to examine the effects of iodine supplementation of layer diets on production parameters, egg quality and egg iodine content can be considered as tolerance study. 120 laying hens (6 replicates with 20 hens each) were fed balanced diets with 0, 3, 6, 12 and 24 mg iodine as calcium iodate kg -1 diet for 30 weeks, respectively.…”