Avaliação de milhos de diferentes densidades para frangos de corte

Abstract

RESUMO Evaluation of corn with different densities for broilersABSTRACT -The objective of this work was to determine the nutritional value of corn of four different qualities, obtained by stratification in densimetric table, for broilers at different ages. The corns were designed as: MDA -high density corn; MDI -medium density corn; MDB -low density corn and MDO -original density corn, composed of 25% MDA, 50% MDI and 25% MDB. Three biological assays were carried out by using the traditional total excreta collection method for determination of nitrogen corrected apparent metabolizable energy (AMEn). The first metabolism assay was carried out with Cobb chicks at 14 to 17 days of age, the second assay with chicks at 25 to 28 days of age and the third with chicks at 38 to 41 days of age. Chemical analyses were made for determination of the nutritional profile, classification of the grains according to density and comparison by estimates of energy value prediction equations. The values of AMEn of corns of different qualities (MDA, MDI, MDB and MDO) determined in broilers in initial phase were: 3562, 3382, 3198 and 3357 kcal/kg for growth phase and for final phase they were 3576, 3555, 3229 and 3416 kcal/kg and for the finish phase they were 3610, 3554, 3354 and 3585 kcal/kg, respectively. These results prove that significant energy losses of the lowest quality corns and the efficiency of the densimetric Zootec., v.40, n.7, p.1554-1561, 2011

Metabolizable Energy For Chickens Of High And Low Density Corn Fractions Segregated In Densimetric Table

“…In previous studies (Silva et al, 2008;Silva et al, 2011) the magnitude of the difference favoring the MEn of the corn segregated for high density was greater than reported here and the reason for that is not clear. One possible reason is that the difference in hectoliter weight, as mentioned above, was greater than in this study.…”

“…Based on the above considerations, it was hypothesized that corn segregation in densimetric table may separate grains according to certain characteristics resulting in contrasting MEn for chickens. The improvement in MEn for the high-density corn determined by Silva et al (2011) was based on only one corn hybrid, which was produced especially for the study, but the reason for the difference in MEn values has not been pointed out. The efficacy of densimetric table in segregating grains of different types or textures has not been compared.…”

“…In a previous study (Silva et al, 2011), it was observed that when corn was segregated in densimetric table, the high density fraction resulted in significantly increased nitrogen-corrected metabolizable energy (MEn) for chickens of different ages compared to the low density fraction. The densimetric table segregates the individual grains based on the specific density, but the usual unit to evaluate this property of grains in the industry is the apparent density, known as "test weight", or, more appropriately, "hectoliter weight".…”

Utilization of Different Corn Fractions by Broilers

“…These effects were also observed by Silva et al (2008) and Silva et al (2011); however, these authors did not determine coefficients of metabolizability. Nutritional level changes do not always alter digestive use of nutrients.…”

“…This classification is not useful because grains of the same type may have different chemical content, which affects their nutritional and energy values (Silva et al 2008;Silva et al, 2011). There is little information…”