RESUMO
Two experiments were conducted to evaluate the chemical and nutritional values of 5 tannin-free fava bean (FB) cultivars (FB9, FB10, FB13, FB17, and FB24) on growth, visceral organ size, and blood clinical chemistry of broiler chicks fed a corn-soybean meal 48 (SBM48) diet containing 30% tannin-free FB. In the first experiment, 49 Hy-line roosters, 55 wk of age, were individually precision-fed 30 g of each FB cultivar and soybean meal 44 (SBM44). Protein, methionine, and lysine contents of the FB seeds (0.005% tannin) were 27.7, 0.23, and 1.98% of DM, respectively. The AMEn of all FB cultivars was 2,839 kcal/kg and higher (P < 0.05) than SBM44. The true lysine digestibility of FB10 (94.1) was higher (P < 0.05) than FB9 (89.0%) and FB24 (89.2%), but comparable with the other fava beans. The FB cultivar's true methionine digestibilities were similar among each other and to SBM44. In a battery feeding trial, 6 corn-SBM48 diets containing 0 (control) or 30% of FB9, FB10, FB13, FB17, or FB24 seeds were each fed to Ross 308 1-wk-old male broiler chicks for 14 d. The determined FB nutrient values were used in formulating FB-containing diets. Birds fed FB-containing diets had better (P < 0.05) weight gain and feed conversion than those of the control. When compared with the control birds, relative weights of abdominal fat pad and liver were reduced (P < 0.05) by 30% inclusion of all dietary FB varieties, except for FB17 and FB13, respectively. Broiler chicks fed the FB13 diet had plasma thrombocyte and white blood cell (WBC) differential counts higher (P < 0.05) than those fed the FB10 diet and WBC count higher (P < 0.05) than the birds fed the FB17 diet. In conclusion, tannin-free FB was lower in protein, methionine, and lysine, but higher in AMEn, compared with SBM44. Moreover, FB seeds, especially FB10, can be included in a broiler chick diet with no adverse effects on performance, but FB13 increased WBC count.
