Egg quality analysis and performance of laying hens fed different levels of calcium

Abstract

This study was conducted to examine the quality of eggs and the performance of laying hens fed different levels of calcium. The study was carried out at the Poultry Unit of University of Port Harcourt Teaching and Research Farm, Choba, Port Harcourt, Rivers State. One hundred and twenty black Harco birds were used for the study using the completely randomized design. The laying birds were fed with diets consisting of different level of calcium (Ca), which comprised mainly of limestone and bone meal such that treatment 1 (T1) had 2.5 % Ca, T2 ? 3.5%, T3 ? 4.5% and T4 ? 5.5% Ca, respectively. All the birds were raised within four treatment groups which had three replicates of 10 birds each. At the termination of the study, the eggs and the feed records were used to compute the hen-day production (HDP), feed intake, number of eggs laid per hen, dozens of eggs laid per hen, feed consumed per dozen egg, cost of feed per dozen egg produced and mortality. Six eggs were collected from each replicate to study the eggs external quality (egg weight and width, the weight of the shell, the egg shape index, egg length, shell index and thickness) and internal quality (albumen weight, yolk diameter, yolk height and index, yolk pH and pH of the albumen, albumen height, yolk weight, yolk ratio and yolk albumen ratio). The study revealed that significant (P<0.05) differences existed in the performance parameters such as the hen-day production (HDP), feed intake, number of eggs laid per hen, dozens of eggs produced per hen, feed consumed per dozen egg produced and the cost of feed per dozen egg produced. The hens fed the T2 and T3had the highest HDP, those fed the T3andT4 had better feed conversion while the feed cost for T3 feed was the best (the least). Significant differences were also observed in some of the external and internal parameters of the eggs, including, the egg weight, yolk weight, yolk height, yolk index and Haugh unit (HU) while others were not affected. Although the egg from T4 had the highest HU, eggs from all the treatment were within the 'AA' group (HU of more than 72) termed high quality egg. The study showed that farmers can use Ca levels of 3.5 and 4.5% in the diet of the layers and obtain better HDP. However, the diet which had the 4.5% Ca inclusion, gave the best feed conversion and the least cost of the diet per dozen egg produced and was recommended for layers in the humid tropical zone.