Particle size of oyster shell meal and calcium: phosphorus ratios in broiler diets / Efeito do tamanho de partícula da farinha de ostras e relações cálcio: fósforo em dietas para frangos de corte

The effects of Ca:P total ratio and particle size of oyster shell meal (OSM) were evaluated in broiler diets. In Experiment 1, 800 broilers (22-42 days old) were distributed in a 2×2 factorial design, with two Ca:P ratios (1.7 and 2.0:1) and two OSM particle sizes (coarse = 1,354 µm and fine = 428 µm), totaling four treatments with 10 repetitions with 20 broilers. Feed intake, weight gain, and feed conversion ratio were calculated. In Experiment 2, 1,280 broilers were distributed in a 2×2×2 factorial design (1.7 and 2.0:1 Ca:P ratios; coarse and fine OSM; male and female broilers), with eight treatments and 16 repetitions with 10 broilers. Apparent metabolizability of dry matter, Ca, P, and apparent metabolizable energy (AME), as well as bone resistance, bone weight, ash, Ca, and P content in the tibia were assessed. Growth performance was not affected (P > 0.05). Coarse OSM increased tibia Ca content in male broilers (P < 0.001), and higher Ca:P ratio improved bone ash and bone resistance in both sexes (P < 0.001), but reduced P content in male broilers (P < 0.05); male broilers displayed heavier bones with higher ash content than females (P < 0.05). Metabolizability of Ca was improved with coarse OSM (P < 0.05); whereas metabolizability of DM, P, and AME was not affected (P > 0.05). In conclusion, diets with a Ca:P total ratio of 2.0:1 containing coarser OSM improved bone mineral composition, particularly in male broilers, and coarse OSM improved the metabolizability of Ca in broilers regardless of the Ca:P total ratio or broiler sex.

Dois experimentos foram conduzidos para avaliar os efeitos do tamanho de partícula da farinha de ostras (FO) e relação Ca:P total em dietas para frangos de corte. No primeiro experimento, 800 frangos (22 a 42 dias) foram distribuídos em um delineamento fatorial 2x2: 2 relações Ca:P (1,7 e 2,0:1) e dois tamanhos de partícula da FO (grossa = 1354 µm e fina = 428 µm), totalizando quatro tratamentos com 10 repetições de 20 aves. O consumo de ração, o ganho de peso e a conversão alimentar foram calculados. No segundo experimento, 1.280 frangos foram distribuídos em um fatorial 2x2x2 (relações Ca:P 1,7 e 2,0:1; FO grossa e fina; aves machos e fêmeas) com oito tratamentos e 16 repetições de 10 aves. Foram avaliados: metabolizabilidade aparente da matéria seca, Ca e P, energia metabolizável aparente (EMA), peso e resistência óssea, conteúdo de cinzas, Ca e P na tíbia. As variáveis de desempenho não foram afetadas (P > 0,05). O uso de FO grossa aumentou o conteúdo de Ca na tíbia de frangos machos (P < 0,001), e a relação Ca:P de 2,0:1 aumentou o conteúdo de cinzas e aprimorou resistência óssea em ambos os sexos (P < 0,001), porém reduziu P na tíbia dos machos (P < 0,05); frangos machos também tiveram ossos mais pesados e maior conteúdo de cinzas do que fêmeas (P < 0,05). A metabolizabilidade de Ca foi melhorada com FO grossa, enquanto a metabolizabilidade da matéria seca, P, e EMA não foram afetadas (P > 0,05). Conclui-se que as dietas com relação Ca:P de 2,0:1 e com FO grossa resultaram em melhor composição mineral óssea - particularmente em frangos machos - e a FO grossa melhorou a metabolizabilidade de Ca independentemente da relação Ca:P ou do gênero das aves.

Calcium particle size and feeding time influence egg shell quality in laying hens

An experiment with Leghorn laying hens was undertaken to determine the effect of oyster shell particle size and feeding time on different production variables, calcium retention, plasma calcium content and egg internal and external quality. Two hundred Leghorn layers (40 weeks old old) were allocated in five dietary treatments with four replicates during ten weeks. Two particle size combinations (wherein 50% of calcium substituted by medium or coarse particles (1-2 mm and 2-4 mm respectively) and two feeding time (8-pm or 9-am) were compared against a control diet (100% ground, 0.05). Hens fed diets containing coarse Ca had significantly greater feed intake and calcium content of excreta (p > 0.05), whereas medium particle size reduced feed intake compared to control. Coarse particle size and feeding time at 9-pm significantly increased the calcium content of egg shell, egg shell thickness, egg surface area (ESA) and shell weight per unit surface area (SWUSA) (p < 0.05). Plasma calcium concentration, gizzard digesta calcium content and egg specific gravity were not affected by treatments (p > 0.05). Providing of calcium at 9-pm resulted an increase of egg shell (%), shell weight and thickness (p < 0.05). The results have shown that substitution of fine oyster shell with 50% coarse particles (2-4 mm) and feeding time at 9-pm have better effects on egg shell quality.(AU)

Calcium particle size and feeding time influence egg shell quality in laying hens

An experiment with Leghorn laying hens was undertaken to determine the effect of oyster shell particle size and feeding time on different production variables, calcium retention, plasma calcium content and egg internal and external quality. Two hundred Leghorn layers (40 weeks old old) were allocated in five dietary treatments with four replicates during ten weeks. Two particle size combinations (wherein 50% of calcium substituted by medium or coarse particles (1-2 mm and 2-4 mm respectively) and two feeding time (8-pm or 9-am) were compared against a control diet (100% ground, 0.05). Hens fed diets containing coarse Ca had significantly greater feed intake and calcium content of excreta (p > 0.05), whereas medium particle size reduced feed intake compared to control. Coarse particle size and feeding time at 9-pm significantly increased the calcium content of egg shell, egg shell thickness, egg surface area (ESA) and shell weight per unit surface area (SWUSA) (p 0.05). Providing of calcium at 9-pm resulted an increase of egg shell (%), shell weight and thickness (p < 0.05). The results have shown that substitution of fine oyster shell with 50% coarse particles (2-4 mm) and feeding time at 9-pm have better effects on egg shell quality.