Níveis de cálcio e granulometrias do calcário para frangas de reposição no período de 3 a 12 semanas de idade

Abstract

RESUMO -Realizou-se um experimento com o objetivo de avaliar os efeitos dos níveis de cálcio e das granulometrias do calcário na ração sobre os desenvolvimentos corporal e morfométrico do trato digestório de frangas de reposição. Foram utilizadas 1.400 frangas de reposição da linhagem Lohmann LSL, em delineamento inteiramente casualizado, em esquema fatorial 5 x 2 (níveis de cálcio x granulometrias do calcário), com cinco repetições de 28 e 18 aves por parcela, respectivamente, nos períodos de 3 a 7 e de 8 a 12 semanas de idade. As dietas experimentais, à base de milho, farelo de soja e farelo de trigo (trigo somente na recria), foram formuladas para ser isoprotéicas, isocalóricas e isofosfóricas (fosfato monoamônio). Além da suplementação com minerais, vitaminas e fitase (500 FTU/kg), as dietas foram acrescidas de calcário em granulometrias fina (DGM=0,135 mm) e grossa (DGM=0,899 mm) para apresentar os níveis de 0,60; 0,75; 0,90; 1,05 e 1,20% de cálcio total na dieta. Avaliaram-se o desempenho no período de 3 a 12 semanas, a morfometria do trato digestório e os teores de cinzas e minerais na tíbia de aves de cada parcela. O consumo de ração aumentou de forma linear com a elevação dos níveis de cálcio. Não houve diferenças significativas no ganho de peso, na conversão alimentar, na porcentagem do trato digestório e no comprimento do metatarso. Maiores teores de cinzas foram obtidos em frangas que receberam o nível de 0,60% de Ca e maior comprimento do intestino delgado em aves recebendo a granulometria grossa. O nível de 0,60% de cálcio e o calcário na granulometria grossa (DGM=0,899 mm) foram ideais para o melhor desenvolvimento esquelético, o menor consumo de ração e o maior comprimento do intestino delgado.Palavras-chave: cálcio, morfometria, nutrição de monogástricos, poedeira, trato digestório Calcium levels and particle size of limestone for replacement pullets in the period from 3 to 12 weeks old ABSTRACT -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 12 th week old were evaluated. The feed intak...

Age and Calcium Sources in Laying Hen Feed Affect Calcium Digestibility

“…This greater intake of these feed particles may interfere with the dwell time of the feed in the gizzard and the rate of intestinal transit [1], leading to greater satiety of the animal and decreased FI. This finding corroborates that found by Geraldo et al [26], when evaluating two limestone granulometry (0.135 mm versus DGM = 0.899 mm) during 8 to 12 weeks of age of Lohmann-LSL birds, observed lower IF of older birds that consumed feed with limestone with higher granulometry.…”

Use of radiograph optical densitometry to monitor bone quality in broiler breeders

“…Ash percentages are different from the results presented by Geraldo et al (2004a) and Geraldo et al (2004b). Diets containing finely ground limestone were used in these previous studies and ash percentages were reported to range between 57.08 and 58.61% in the tibias of 5-week-old rearing pullets (Lohmann-LSL) and between 58.23 and 59.77% in 12-week-old pullets.…”

The effect of dietary phytase on broiler performance and digestive, bone, and blood biochemistry characteristics

“…According to Nelson & Walker (1964) and Pereira et al (2012), bone ash content is the most efficient parameter to estimate the amount of phosphorus released by phytase in corn-and soybean meal-based diets. Geraldo et al (2006) found 1.88% reduction in tibial ash content for each 1% increase in dietary calcium levels. The dietary supplementation of phytase allows reducing dietary available phosphorus in 0.15% and Ca in 0.15% (Gomide et al, 2011).…”