Nutritional evaluation of sorghums grown with different organic fertilizers for slow-growing broilers

Abstract

The aim of this study was to evaluate the effects of sorghums grown with different organic fertilizers on the chemical composition, energy values, and nutrient metabolizability coefficients, as well as their use for feeding slow-growing broilers. Two trials were performed. In the first experiment, 200 21-day-old broilers were distributed in a completely randomized design (CRD), with five treatments and four replicates of 10 birds per experimental unit. The treatments consisted of a control diet and four test diets (sorghum fertilized with crotalaria, sorghum fertilized with millet, sorghum fertilized with humus, and sorghum without fertilization), including sorghum at 30% in the control diet. The apparent metabolizable energy (AME), apparent metabolizable energy corrected for nitrogen balance (AMEn), metabolizability coefficients of dry matter, crude protein, and gross energy were evaluated. In trial 2, 200 1-day-old chicks were used in a CRD with five treatments (T1 – control diet with commercial corn, T2 – sorghum fertilized with crotalaria, T3 – sorghum fertilized with millet, T4 – sorghum fertilized with humus, and T5 – sorghum without fertilization) and four replicates of 10 birds per experimental unit. Weight gain, feed intake, feed conversion, and final weight at 28 days were evaluated. The values of AME and AMEn of sorghums fertilized with crotalaria, millet, humus, and sorghum without fertilization were 2894 Kcal kg-1 and 2881 Kcal kg-1; 2736 Kcal kg-1 and 2675 Kcal kg-1; 2727 Kcal kg-1 and 2694 Kcal kg-1; and 2994 Kcal kg-1 and 2959 Kcal kg-1, respectively. The metabolizable coefficients of dry matter, crude protein, and gross energy were 76.04%, 42.01%, and 75.25% for sorghum fertilized with crotalaria; 77.50%, 50.77%, and 75.95% for sorghum fertilized with millet; 77.62%, 46.39%, and 75.54% for sorghum fertilized with humus; and 75.83%, 39.53%, and 74.71% for sorghum cultivated without fertilization, respectively. The dietary use of sorghum cultivated with different fertilizers did not affect (P > 0.05) weight gain, feed intake, feed conversion, and final weight. Green manures with crotalaria, millet, and humus (bovine manure) are alternatives that can be used on sorghum crops because they resulted in grains with adequate nutritional composition, energy values, and metabolizable coefficients for slow-growing broilers from 1 to 28 days of age.