Implications of drought stress on corn or sorghum utilization in broiler chicks

Abstract Text: A total of 512 broiler chicks (Cobb × Cobb, 46.7 ± 0.10 g) were fed 1 of 8 dietary treatments to determine the effects of environmental conditions, grain type, and/or carbohydrase inclusion on starter broiler chick growth and mortality. Chicks were hatched and allotted to battery cages (8 birds/cage, 8 cages/treatment) for an 18-d experiment. Birds were weighed and feed disappearance measured to determine ADG, ADFI, and G:F. Daily mortality was accounted for, and data were log transformed to normalize distribution. Treatments were arranged in a 2 × 2 × 2 factorial (drought vs. normal conditions, corn vs. sorghum, and commercial carbohydrase vs. no enzyme) and data were analyzed with the MIXED procedure of SAS. Feeding chicks grains raised in drought conditions did not affect (P > 0.22) final body weight, ADG, ADFI, or mortality. However, chicks used grain more efficiently if it was raised in normal vs. drought conditions as evidenced by G:F (P = 0.02; 1.29 ± 0.011 vs. 1.32 ± 0.012, respectively). This was due to greater feed efficiency in the normal corn diets compared to drought-stressed corn diets (1.26 vs. 1.33, P = 0.01) as there was no significant difference in sorghum diets (1.31 vs. 1.32, P = 0.80). Interestingly, there were no main effect differences (P > 0.20) between grain type or enzyme inclusion for any measured variable, which suggests that poultry producers may substitute sorghum for corn, and that carbohydrase inclusion is not beneficial during the first 18-days after hatching. However, nutrients from drought-stressed corn are converted less efficiently by broiler chicks in the starter period.

Keywords: carbohydrase, drought, sorghum