Resumen

GARCIA, Elis Regina de Moraes; BATISTA, Natália Ramos; DA CRUZ, Flávia Kleszcz  y  FILHO, João Antonio Barbosa. Limestone particle size and performance and egg quality of laying hens in late production: desempeño y calidad de los huevos de ponedoras al final de la producción. Zootecnia Trop. [online]. 2012, vol.30, n.4, pp.311-316. ISSN 0798-7269.

The objective of this study was to evaluate the performance and egg quality of laying hens fed diets with different particle sizes of limestone (small - CF: 0.145 mm and large - CG: 3.18 mm). For this experiment, 160 laying hens at 56 weeks of age were used, during a trial composed of 63 days, with three cycles of 21 days. The birds were distributed in a completely randomized design with five treatments and four replications with eight birds each. The treatments consisted in the following proportions of limestone: 100% CF; 25% CG e 75% CF; 50% CG e 50% CF; 75% CG e 25% CF e 100% CG. At the end of each cycle analyzed variables were feed intake, egg production, egg mass, feed conversion (kg/kg and kg/dz), average egg weight, percentage and shell thickness, yolk index and Haugh unit values. The results were submitted to analysis of variance and regression analysis (P<0.05). The particle size of limestone linearly reduced feed intake, the percentage of production, egg mass and feed conversion (kg/kg, kg/dz), but got no effect on the parameters of internal quality and egg shell. The increasing replacement of limestone with fine grained (0.145 mm) thick by (3.18 mm) in the diet of laying hens in late production negatively influences the performance characteristics of the laying hens, with no effect on the external and internal quality of eggs.

Palabras clave : calcium; egg production; egg shell quality; particle size; unity Haugh.

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