Levels of calcium and calcium/available phosphorus ratio in forced molting lightweight laying hens
| Autor: | Almeida, Rodrigo Lopes de |
|---|---|
| Přispěvatelé: | Rostagno, Horácio Santiago, Albino, Luiz Fernando Teixeira, Gomes, Paulo Cezar, Barreto, Sérgio Luiz de Toledo, Pupa, Júlio Maria Ribeiro |
| Jazyk: | portugalština |
| Rok vydání: | 2011 |
| Předmět: | |
| Zdroj: | LOCUS Repositório Institucional da UFV Universidade Federal de Viçosa (UFV) instacron:UFV |
| Popis: | Conselho Nacional de Desenvolvimento Científico e Tecnológico In order to determine calcium nutritional requirement and the best calcium: available phosphorus ratio for commercial laying hens in second production cycle (71 weeks old), was conducted an experiment with four periods of twenty-eight days each one. Three hundred seventy-eight Hy-Line W36 forced molting laying hens were used, distributed in a randomized experimental block design in a 3 x 3 factorial arrangement, composed of three levels of calcium (3.7; 4.0; and 4.3%) and three calcium: available phosphorus ratios (9,76:1; 10,81:1 and 12.12:1), totaling nine treatments with seven replicates with six birds each. The following parameters were evaluated: 1) performance: posture, feed intake, egg weight, egg mass, feed conversion (egg dozen and egg mass) and weight gain; 2) Shell quality: percentage, weight and thickness of egg shell; egg specific gravity; contents of ash, and calcium and phosphorus in the egg shell; 3) bone characteristics (tibia weight, contents of ash, calcium and phosphorus in the tibia); 4) calcium and phosphorus balance (calcium and phosphorus intake, contents of ash, calcium and phosphorus in excretion and retained by the birds) and 5) mortality. There was interaction (P0,05) the quality parameters of shell. Was found that increased levels of calcium caused a linear increase(P 0,05) the bone characteristics. Regarded to calcium and phosphorus balance, dietary calcium levels promoted a linear effect (P0.05). There was no effect (P>0.05) of levels of calcium on retention and excretion of phosphorus by birds, both in percentage and in absolute value, either. The calcium and phosphorus ratios did not influence (P>0.05) calcium intake by the birds, contents of mineral matter and calcium in the excreta in percentage and in absolute terms as well, retention of calcium by birds, in percentage and in absolute value as well, the percentage of phosphorus in feces and the percentage of phosphorus retained by the birds. However, when the retention of phosphorus was determined in absolute terms, the calcium and phosphorus ratios promoted a linear effect (P0,05) sobre os parâmetros de qualidade de casca. Quanto aos parâmetros ósseos, verificou-se que o aumento dos níveis de cálcio causou aumento linear (P0,05) sobre os parâmetros ósseos. Com relação ao balanço de Ca:Pd, os níveis de cálcio da ração promoveram efeito linear (P0,05) dos níveis de cálcio sobre a excreção e retenção de fósforo pelas aves, tanto em porcentagem, quanto em valor absoluto. As relações Ca:Pd não influenciaram (P>0,05) o consumo de cálcio pelas aves, os teores de matéria mineral e de cálcio nas excretas (tanto porcentagem, quanto em valor absoluto), a retenção de cálcio pelas aves (tanto em porcentagem, quanto em valor absoluto), a porcentagem de fósforo nas excretas e a porcentagem de fósforo retido pelas aves. No entanto, quando a retenção de fósforo foi determinada em valor absoluto, as relações Ca:Pd da ração promoveram efeito significativo (P |
| Databáze: | OpenAIRE |
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