Abstract
This study was conducted to evaluate the nutritional values of fractions of damaged corn. One hundred and eighty 22-d-old Cobb 500 male broilers were distributed in batteries according to a completely randomized design with six treatments of six replicates each. The treatments consisted of diets containing five corn fractions, classified as sound, fermented, insect-damaged, mold-damaged, or reference corn. The test diets consisted of 60% of reference diet + 40% of each corn fraction. Only the reference corn fraction included all the fractions at different proportions (0.8% fermented, 0.05% insect-damaged, 3.3% mold-damaged, and 95.85% sound grains). The method of total excreta collection was used to determine AMEn values and metabolizability coefficients of dry matter (MDM), crude protein (MCP), ether extract (MEE), and gross energy (MGE) of the reference corn and its fractions. The density values of the corn fractions were used to calculate the correlations among the evaluated parameters. The evaluated corn fractions presented different compositions values. The insect-damaged and mold-damaged grains presented higher CP level, lower density, and MDM and MCP coefficients compared with the other fractions. However, calculated AMEn values were not significantly different (p>0.05) among corn fractions. A low correlation between density and AMEn content (r 0.8) were calculated. Although the evaluated corn fractions presented different nutritional values, there were no marked differences in their utilization by broilers.
Highlights
Corn (Zea mays) is grown in almost all over the Brazilian territory, with an average of 80 million tonnes produced per year (Conab, 2015)
The sound corn (T2) and the reference corn (T6) presented similar dry matter (DM), crude protein (CP), crude fiber (CF), ether extract (EE), and gross energy (GE) (Table 1) contents when compared to the Brazilian Tables (Rostagno, 2011)
The insect-damaged and molddamaged grains had higher CP levels compared with sound corn (17.8 and 26.0%, respectively)
Summary
Corn (Zea mays) is grown in almost all over the Brazilian territory, with an average of 80 million tonnes produced per year (Conab, 2015). 60 of 23rd of December, 2011 (MAPA, 2011) This official system includes seven grain fractions: intact, molddamaged, broken, sprouted, insect-damaged, hollow, and broken. The feed industry often uses low-quality corn (Type 3), characterized by up to 3% foreign material, impurities and fragments; 27% broken grains; and a maximum of 10% mold-damaged and sprouted grains. 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).
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