Effect of calcium sources and particle sizes on performance characteristics, age at first egg and blood parameters of egg type chicken

Abstract

The importance of Calcium to animals in general and egg type chicken in particular has been of interest to researchers for a long time. This interest in calcium varies from the search for the optimal sources of calcium for egg type chicken in their feed, a search for the optimal or ideal calcium in their feed, as well as the influence of calcium (positive and negative) on egg production and metabolism. This study was conducted to evaluate the effect of using different calcium sources (eggshell, limestone and oyster shell) and particle sizes (<1mm, 1-2mm and 2-3.8mm) in the diets of 540, one day old pullet chicks (Nera Black) up to pre - laying phase in a 3 x 3 factorial design consisting of nine dietary treatments. There were 60 birds per treatment replicated thrice with 20 birds each. Three isocaloric and isonitrogenious diets with three calcium particles sizes were formulated for each of the calcium sources totaling nine diets. The experiment comprised of starter (2-9 weeks), grower (10-17 weeks) phase and pre- laying (18-22 weeks) respectively. The levels of oyster shell, limestone and egg shell were adjusted so that the level of calcium in the chick and grower mashes was 1%. Growers mash was also used for pre-laying phase. Data were collected on growth performance, serum calcium, alkaline phosphatase and age at first egg. Diets containing eggshell of particle size <1mm produced birds with the highest (p<0.05) final live weight (523.64g) at the starter phase and also had the best overall live weight (1476.62g) at 17 weeks. Diets that contained eggshell of particle size 1-2mm recorded the highest (p<0.05) value for serum calcium (8.82mg/dl) and alkaline phosphatase (53.55u/l). Birds in this group were the first to start laying. It can be concluded that rapid improvement in growth could be achieved by the inclusion of eggshell of particle size (<1mm) in the diets as the main calcium source and eggshell of particle size (1-2mm) for older pullet to enhance early egg production.