Influence of different bone meal particle size induced calcium specific appetite on performance and egg quality parameters of layer chickens

Abstract Effects of free choice feeding of different bone meal (BM) particle sizes on performance and egg quality traits of layer chickens were assessed. A total of 56-weeks old, 128 Hy-line White layers (BW±SD; 1500±18 g) were assigned randomly into 16 cages of 8 birds each. Four dietary treatments (Layer Diet/Control; Layer diet+1-2 mm BM; Layer diet+2-3 mm BM; Layer diet+3-4 mm BM) based on BM particle sizes were choice fed for five weeks. Dry matter (DM), calcium (Ca), total phosphorus (TP), ash content, particle size distribution and in-vitro solubility of BM were tested. Bird’s performance and egg quality traits were examined over 5 weeks period. The DM, Ca, TP and ash content of BM were 893, 79, 44 and 476 g/kg, respectively. The geometric mean diameter (GMD) and the geometric standard deviation (GSD) of BM were 1.7 and 1.6 mm, respectively. In-vitro solubility of 1-2 mm, 2-3 mm and 3-4 mm BM particles were 56.3, 47.5 and 39.8 %, respectively. Feeding BM increased BM intake, Ca intake, reduced damaged egg % and increased laying %. Birds fed BM having 2-3 mm particles performed the best. Bone meal significantly (P<0.05) improved the egg shell thickness with maximum thickness recorded from birds fed 2-3mm BM particle size. Feeding BM had both 2-3 and 3-4 mm particles improved (P<0.05) shell ratio and unit surface shell weight. The present data concluded that feeding BM processed into 2-3 mm particle size is the best in improving overall performance and egg quality traits of layer chickens.