Níveis de cálcio em rações de poedeiras comerciais no segundo ciclo de postura

This study evaluated the effects of different sources of vitamin D and calcium levels on performance, egg quality and bone strength of hens in the second production cycle. A total of 384 Hy-Line W36 birds with 80 weeks of age were used, alloted into 3 x 4 factorial design (sources of vitamin D: cholecalciferol; 25(OH)D 3 and 1.25(OH) 2 D 3 x calcium levels: 2.85, 3.65; 4.45 and 5.25%) with four replicates and eight birds each. The performance was evaluated for three cycles of 28 days each, egg quality was evaluated in the last four days of each cycle and bone strength on the last day of the experimental period. There was no interaction (p> 0.05) between the different sources of vitamin D and calcium levels in all parameters evaluated. There was a quadratic effect (p<0.05) of calcium levels in egg production and feed conversion (kg/kg and kg/dz), with better results at levels of 4.12%, 4.09% and 4.14%, respectively. Calcium levels had no effect (p> 0.05) in the egg weight and Haugh unit, but there was a linear increase (p <0.05) in the percentage and eggshell thickness, in specific gravity and bone strength. The different sources of vitamin D influenced (p<0.05) the egg production rate, feed conversion, egg weight and Haugh unit. Thus, the results of this study suggest that the recommended calcium level for laying on second cycle is between 4.09% and 4.14% and that the metabolites cholecalciferol and 25(OH)D 3 improved the performance and egg quality. Regarding bone strength was improved as the calcium levels were increased in diets.

Section: Resultscontrasting

confidence: 44%

Effect of different vitamin D sources and calcium levels in the diet of layers in the second laying cycle

Nascimento

Murakami

Guerra

et al. 2014

“…There was no influence of clinoptilolite or calcium levels on Haugh units, as previously found by other authors (Rodrigues et al, 2005;Geraldo, 2006;Pelícia et al, 2009).…”

Section: Effects Of Dietary Clinoptilolite and Calcium Levels On The supporting

confidence: 86%

Effects of dietary clinoptilolite and calcium levels on the performance and egg quality of commercial layers

Berto

Garcia

Pelícia

et al. 2013

Among the different feed additives studied in poultry production, clinoptilolite, an aluminosilicate capable of adsorbing harmful substances and of improving live performance and egg and meat quality, was evaluated. The objective of the present study was to evaluate the influence of dietary clinoptilolite and calcium levels on the performance and egg quality of layers. In total, 576 layers were distributed according to a completely randomized experimental design in a 3 x 4 factorial arrangement (three calcium levels-2.5, 3.1, or 3.7% and four clinoptilolite levels-0.0, 0.15, 0.25, or 0.50%), with 12 treatments of six replicates of eight birds each. The experiment included four 28-d cycles. The experimental diets were based on corn and soybean meal. Results were submitted to analysis of variance and means were compared by the test of Tukey at 5% significance level using SISVAR statistical package. There was a significant interaction between the evaluated factors for egg production and feed conversion ratio per dozen eggs and egg mass. The lowest calcium level resulted in worse performance and eggshell quality. Clinoptilolite levels affected albumen and yolk content. It was concluded that up to 0.50% inclusion of clinoptilolite in layer diets does not benefit layer performance or eggshell quality. Although the inclusion of only 2.5% calcium in layer diets is not recommended, it is possible to add 3.1% because it promoted similar results as the recommended level of 3.7%.

“…The results obtained in the analysis of regression for defective eggs may be explained by Rao & Roland (1992), who observed that the time required to release Ito et al (2006) and Oliveira (2002) did not observe any effects of dietary Ca levels on yolk percentage, whereas Geraldo et al (2006b), Rodrigues et al (2005) and Oliveira (2002) also did not detect any effect of Ca levels on Haugh units. Ito et al (2006) did not find any effect of Ca levels on albumen percentage and Haugh units.…”

Section: External Egg Qualitymentioning

confidence: 79%

Calcium levels and limestone particle size in the diet of commercial layers at the end of the first production cycle

Pelícia

Garcia

Móri

et al. 2009

This study evaluated the effect of dietary calcium levels and limestone particle size distribution on first-cycle layer performance and egg quality. A completely randomized experimental design in 4x3 factorial arrangement (four Ca levels -3.0, 3.5, 4.0, 4.5%; and three limestone particle size distributions -100% fine, 50% fine and 50% coarse, 30% fine and 70% coarse) was applied, totaling 12 treatments with six replicates of eight birds each. The treatments did not influence the most of evaluated performance and internal and external egg quality parameters. However, limestone particle size distribution quadratically affected with percentage of defective eggs, with the lowest percentage obtained with the distribution 61.75% fine limestone and 38.25% coarse limestone. Increasing dietary Ca levels significantly increased eggshell weight per surface area and the percentage of Ca excreted in the feces. It was concluded that the combination of the highest dietary Ca level (4.5%) with 50% replacement of fine-particle limestone by coarse limestone results in better eggshell and increases the number of marketable eggs.