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

Abstract

The aim of this study was to examine the effects of various levels of supplemental calcium iodate (CI) on productive performance, egg quality, blood indices and iodine (I) accumulation in the eggs in commercial laying hens. A total of 240 White Leghorn layers (Hy-line W36) were divided through a completely randomized design into six treatments with five replicates and eight hens per each at 32 weeks of age. This experiment lasted for 12 weeks. Concentrations of I in the mash diets were 0.74, 3.13, 5.57, 8.11, 10.65 and 12.94 mg I/kg of feed in treatments 1-6 respectively. The added doses of CI were included 0.0 (control), 2.5, 5.0, 7.5, 10.0 and 12.5 mg/kg of diet for treatments 1-6 respectively. There were no significant differences in productive performance among the treatments. The highest eggshell strength was observed in group fed diet containing 3.13 mg I/kg (p = .014). The highest percentage of calcium and lowest percentage of phosphorus in eggshell were observed in group fed diet containing 12.94 mg I/kg (p = .0001). Feeding hens with diet containing 12.94 mg I/kg increased serum triiodothyronine-to-thyroxine ratio (p = .0001). Serum alanine aminotransferase activity in hens fed diet containing 12.94 mg I/kg was significantly more than control (p = .041). Blood Serum triglycerides in hens fed diet containing 8.11 mg I/kg were significantly higher than control (p = .0001). Edible fraction of the eggs of birds fed diet containing 12.94 mg I/kg was enriched by I almost 3 times more than those fed diet containing 0.74 mg I/kg. The results suggested that egg production, egg mass, feed intake and feed conversion ratio were not significantly affected by dietary I levels. Iodine accumulation in the eggs were increased by increasing dietary I levels and the level of 10 mg/kg CI could supply I enrichment of the eggs.

Supplementation of two sources and three levels of iodine in the diet of laying hens: effects on performance, egg quality, serum and egg yolk lipids, antioxidant status, and iodine accumulation in eggs

“…Besides, with increasing age, there tended to be an increase in the percentage of yolk weight and a decrease in the percentage of albumen weight, which was not altered by dietary iodine. In agreement with our results, Christensen and Ort (1990), Bakhshalinejad et al (2018), and Damaziak et al (2018) reported that dietary inorganic iodine (2.1-12.9 mg/kg as CIOD or KI) had no significant effects on egg yolk and albumen percentages, yolk colour, or Haugh unit. However, Yalçin et al 2004found a linear decrease in albumen index and Haugh unit when the level of dietary iodine increased to 24 mg/kg by using CIOD as the additive, and Lichovnikova et al (2003) reported that even a level of 6.1 mg/kg of iodine could have deleterious effect on Haugh unit in long-term period of treatment (30 wk).…”

“…Our findings are supported by those of Saki et al (2012), who found that eggshell weight and thickness did not respond to dietary inorganic iodine (as CIOD) in a range of 0.8-5.6 mg/kg of diet. However, using the same source of supplement, Bakhshalinejad et al (2018) reported that a level of 10.7 mg/kg of dietary iodine resulted in a reduction of eggshell strength that was independent of weight and thickness of the eggshell. Therefore, the detrimental effect of the EDDI 8 diet on the incidence of abnormal eggs and eggshell strength seems likely to result from a higher level of bioavailable iodine.…”

“…Furthermore, the rate of increase in egg consumption is predicted to be higher in developing countries than in the developed world (Ren 2009). Seising this opportunity, several recent studies have investigated the transfer of iodine from feed into eggs of laying hens (Dobrza nski et al 2001;Yalçin et al 2004;Opali nski et al 2012;R€ ottger et al 2012;Saki et al 2012;Słupczy nska et al 2014;Bakhshalinejad et al 2018). However, the reported iodine concentration of eggs varies significantly due to the variation in age of hens, laying rate, and chemical methods used for iodine determination.…”

“…However, the reported iodine concentration of eggs varies significantly due to the variation in age of hens, laying rate, and chemical methods used for iodine determination. For example, whereas Dobrza nski et al (2001) reported that supplemental dietary iodine at a level of 2.68 mg/kg increased the iodine content of the whole egg (yolk plus albumen) to about 1.05 mg/g, Słupczy nska et al (2014) and Bakhshalinejad et al (2018) reported that such a level of egg iodine was achieved only when the supplementary level of iodine increased to 5 and 13 mg/kg of diet, respectively. Therefore, the available data provide no support for any universal recommendation of a particular level of dietary iodine.…”

Dietary glycerol monolaurate supplementation for the modification of functional properties of egg white protein

“…Fathi et al showed that a diet supplemented with probiotics has a beneficial effects on eggshell quality and resistance to breaking. Bakhshalinejad et al found that calcium iodate supplementation increased the accumulation of iodine in eggs and enhanced eggshell strength. Medium chain fatty acid (MCFA) supplementation of feed has been confirmed to have positive effects on the health, productive performance, immune response and egg quality of laying hens .…”