The effect of level and source of dietary selenium supplementation on eggshell quality.Biol Trace Elem Res. 2010 Feb; 133(2):197-202.BT
A 16-week-long experiment was performed to compare the effect of sodium selenite (SS) and selenium-enriched yeast (SY) supplementation on eggshell quality and also to evaluate breaking force correlation with other parameters of shell quality originating from hens fed with selenium supplementation. One hundred Shaver 579 hens (27 weeks old) with similar body size were randomly divided for five dietary treatments: basal diet without selenium supplementation and basal diets with two levels of selenium supplementation (0.4 or 0.8 mg/kg) via SS or SY. No adverse effect of Se inclusion in hen's feed, regardless of its source, on shell breaking force, shell deformation, shape index, shell thickness and shell percentage, were observed throughout the current study (P > 0.05). Moderate correlations were found between breaking force and nondestructive shell deformation for all diets (P < 0.05). There was no significant overall correlation between egg breaking force and shell thickness or/and percentage shell in the presence of selenium supplementation (P > 0.05). Shape index in all four selenium-supplemented groups was not related to the breaking force (P > 0.05). Selenium supplementation of up to 0.8 mg/kg, regardless of its source, in the diet of laying hens in their first phase of laying does not adversely affect eggshell quality.