Research Note: Corn energy and nutrient utilization by broilers as affected by geographic areas and carbohydrases

Two experiments (Exp.) were con-ducted to evaluate the effects of exogenous carbohy-drases on nutrient and energy utilization of corn with different compositions by broilers. In Exp. 1, a total of 448 Cobb 500 male chicks were distributed in a 2 x 4 factorial arrangement (corn from regions geographically located in the North or South of Brazil x 4 carbohy-drases supplementation), with 8 replicate cages of 7 birds each. In Exp. 2, 672 Cobb 500 male chicks were fed 12 experimental feeds, in a 3 x 4 factorial arrangement [3 corn endosperm compositions (waxy, semi-dent, or semi-flint) x 4 carbohydrases], with 8 replicate cages of 7 birds. Birds were fed semi-purified test diets with 95.9% corn from d 14 to 24 in both studies. In Exp. 1, a-amylase, b-xylanase, or carbohydrase complex (cellu-lase, glucanase, and xylanase) were added to the diet. In Exp. 2, a-amylase, b-xylanase, or a-amylase + b-xyla-nase were supplemented. Digestibility of DM, N, ether extract (EE), Ca, and P as well as AME, AMEn, and IDE were determined. In Exp. 2, jejunal starch digest-ibility was determined on d 24. Data were subjected to analysis of variance and means were compared by Tukey test (P <= 0.05). Corn from the North origin had higher AME, AMEn, and digestibility of DM and N compared to the South (P <= 0.05). Amylase supplementation led to increases of 3% in AME and 2% in N digestibility when compared to the non-supplemented feeds (P <= 0.01). In Exp. 2, the highest ME values and EE digest-ibility were observed in the semi-flint corn compared to the waxy, whereas the semi-dent presented the highest digestibility of N and starch. Corn diets supplemented with amylase + xylanase had improvements of 2.5% AMEn and 3% starch digestibility. In conclusion, energy and nutrient utilization of corn by broilers depend on the region where it was grown. Corn genetics, expressed by the endosperm composition, and carbohydrase sup-plementation influenced energy and nutrient utilization by broilers.

Automated summary

Two experiments were conducted to evaluate the effects of exogenous carbohydrases on nutrient and energy utilization of corn with different compositions. The results showed that the energy value, digestibility of dry matter and nitrogen of corn depended on the region where it was grown and the genetic characteristics of corn. Supplementation of exogenous carbohydrases could improve the utilization efficiency of energy and nutrients.