Revista Brasileira de Zootecnia
On-line version ISSN 1806-9290
GERALDO, Adriano et al. Calcium levels and particle size of limestone for replacement pullets in the period from 3 to 12 weeks old. R. Bras. Zootec. [online]. 2006, vol.35, n.1, pp. 113-118. ISSN 1806-9290. http://dx.doi.org/10.1590/S1516-35982006000100014.
The effects of feeding different calcium levels and limestone particle sizes on body and morphometric development of the digestive tract in replacement pullets were evaluated in this trial. One thousand and four hundred Lohmann LSL replacement pullets were assigned to a complete randomized design with a 5 x 2 factorial (calcium levels and limestone particle size) and five replicates of 28 and 18 birds/plot, respectively, for the periods from 3 to 7 and from 8 to 12 weeks old. The experimental diets contained: corn, soybean meal and wheat meal (wheat only at growing phase) and were formulated to be isonitrogenous, isoenergetic and isophosphorus (monoammonium phosphorus). Diets were supplemented with minerals, vitamins and phytase (500 FTU/Kg) and added with limestone in fine (DGM = 0.135 mm) and gross (DGM=0.899 mm) particle sizes to meet the levels of 0.60, 0.75, 0.90, 1.05 and 1.20% of dietary total calcium. The performance in the period from 3 to 12 weeks, morphometry of the digestive tract and contents of tibia ashes and minerals in animals slaughtered at 12th week old were evaluated. The feed intake increased linearly as the dietary calcium levels increased. No significant differences on weight gain, feed conversion, percentage of digestory tract and metatarsus length were noticed. Better tibia ash content were observed with 0.60% of calcium and a longer length of the small intestine in pullets fed diet with gross particle size of limestone. The diet with calcium level of 0.60% and gross particle size of limestone resulted in better esqueletic development, worse feed intake and larger length of small intestine.
Keywords : calcium; digestory tract; hens; morfometric; poultry nutrition.