Abstract
An experiment with Leghorn laying hens was undertaken to determine the effect of oyster shell particle size and feeding time on different production variables, calcium retention, plasma calcium content and egg internal and external quality. Two hundred Leghorn layers (40 weeks old old) were allocated in five dietary treatments with four replicates during ten weeks. Two particle size combinations (wherein 50% of calcium substituted by medium or coarse particles (1-2 mmand 2-4 mmrespectively) and two feeding time (8-pm or 9-am) were compared against a control diet (100% ground, 0.05). Hens fed diets containing coarse Ca had significantly greater feed intake and calcium content of excreta (p > 0.05), whereas medium particle size reduced feed intake compared to control. Coarse particle size and feeding time at 9-pm significantly increased the calcium content of egg shell, egg shell thickness, egg surface area (ESA) and shell weight per unit surface area (SWUSA) (p 0.05). Providing of calcium at 9-pm resulted an increase of egg shell (%), shell weight and thickness (p < 0.05). The results have shown that substitution of fine oyster shell with 50% coarse particles (2-4 mm) and feeding time at 9-pm have better effects on egg shell quality.
Highlights
Calcium (Ca) is a key mineral in laying hens, during the laying period (Araujo et al, 2011)
Dietary treatments consisted of three oyster shell particles sizes namely ground (
Egg weight significantly decreased by treatments 1, 2 and 4 in comparison with control (p < 0.05)
Summary
Calcium (Ca) is a key mineral in laying hens, during the laying period (Araujo et al, 2011). Calcium constitutes approximately 1.5% and 40.0% of BW and eggshell weight respectively (Bölükbasi, Çelebi, & Utlu, 2005). It is usually supplied as calcium carbonate in the form of limestone or oyster shell, or from other sources, such as marine shells. Particle size of calcium sources in layers’ diets is an important factor affected calcium bioavailability Acknowledging this importance, the identification of the Ca bioavailability of different sources and the ideal Ca particle size (generally limestone) in laying hens have been received great interest by researchers for a long time (Araujo et al, 2011; De Witt, Kuleile, Van der Merwe, & Fair, 2008; Ekmay & Coon, 2011; Guinotte & Nys, 1991; Guo & Kim, 2012; Koreleski & Šwiątkiewicz, 2004; Lichovnikova, 2007; Pavlovski, Vitorović, Lukić, & Spasojević, 2003; Pelicia et al, 2011; Saunders-Blades, MacIsaac, Korver, & Anderson, 2009; Skřivan, Marounek, Bubancova, & Podsedníček, 2010)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
