Níveis de cálcio e granulometria do calcário sobre o desempenho e a qualidade da casca de ovos de poedeiras comerciais

Abstract

ResumoO experimento foi realizado com o objetivo de verificar a influência dos níveis de cálcio e combinações do calcário em pó com o calcário em grânulo (pedrisco) sobre o desempenho e a qualidade da casca dos ovos de poedeiras comerciais. Foram utilizadas 360 poedeiras da linhagem Hy-Line branca com 57 semanas de idade, distribuídas em um delineamento inteiramente casualisado, em esquema fatorial 3x5 (3,75; 4,15 e 4,55% de cálcio na dieta e 0, 25, 50, 75 e 100% de uso do calcário em pó em relação ao calcário em grânulo) com quatro repetições de seis aves cada. A produção de ovos, a conversão alimentar, o peso dos ovos, a resistência e espessura da casca foram influenciados pelos níveis de cálcio utilizados. As combinações de calcário em pó com calcário pedrisco utilizadas não apresentaram efeito sobre os parâmetros estudados. O peso médio de ovos foi melhorado quando se utilizou diferentes níveis de cálcio interagindo com diferentes combinações granulométricas do calcário.Unitermos: fonte de cálcio, perda de ovos, produção de ovos, tamanho da partícula AbstractEffects of calcium levels and limestone on laying hen performance and egg shell quality. An experiment was carried out to evaluate the influence of calcium levels and combinations of limestone particle sizes on the laying performance and egg shell quality of hens. Three hundred and sixty Hy-Line laying hens of 57 weeks of age were used, distributed in a randomized design in 3x5 factorial arrangement (3.75, 4,15 and 4,55% of calcium in the diet and 0, 25, 50, 75 and 100% of replacement of limestone powder) with 4 replicates, each consisting of 6 hens. Egg production, feed conversion, egg weight, and strength and thickness off egg shell were influenced by diet calcium levels. No single effect of limestone particle size replacement was found in the studied parameters. The average egg weight was improved when different diet calcium levels, interacting with different combinations of limestone particle sizes, were used.

Limestone particle size and artificial light for laying hens in the second laying cycle

“…The results obtained for the effect of limestone particle size on egg quality are similar to those reported by other researchers (Jardim Filho et al, 2005a;Ito et al, 2006;Murata et al, 2009;Saunders-Blades et al, 2009). According to Murata et al (2009), supplying limestone with large particle sizes may provide higher availability of calcium for eggshell formation.…”

“…The results for effect of limestone particle size on poultry performance resemble those reported by other researchers (Jardim Filho et al, 2005a;Ito et al, 2006;Murata et al, 2009;Saunders-Blades et al, 2009). According to Saunders-Blades et al (2009), the change in the particle size of calcium source does not significantly influence feed intake and consequently the performance, since even poultry subjected to different limestone particle sizes ingest enough nutrients for a good performance.…”

“…According to Murata et al (2009), supplying limestone with large particle sizes may provide higher availability of calcium for eggshell formation. Saunders-Blades et al (2009) reported that as the change in the particle size of the calcium source did not affect feed intake, poultry fed different limestone particle sizes ingest enough nutrients for egg production with good inner quality and shell quality.…”

“…Thus, considering the importance of calcium in eggshell formation and bone metabolism, some researchers (Jardim Filho et al, 2005a,b;Ito et al, 2006;Murata et al, 2009) have reported the importance of studies to assess the influence of calcium sources, as well as their physical and chemical characteristics, aiming at improving the quality of eggshell and skeletal system of laying hens.…”

“…As laying hens age, there is a drop in the eggshell quality due to factors such as lower calcium retention and increased egg weight without increasing the shell weight, in addition to the common bone fragility at the end of the production cycle (Whitehead, 2004;Murata et al, 2009). Almeida Paz et al (2009) reported that regardless of the dietary calcium level, the laying hens mobilize the minerals from bones for eggshell formation, so bone quality reduces as they grow old.…”