RESUMO
This study aimed to determine whether broiler chickens display a preference for Tenebrio molitor larvae (TM) meal by evaluating ingredient acceptability and birds' performance. Sixty 14-day-old male chickens were assigned into two treatment groups (5 birds/pen, n = 6) in a cafeteria-type study: the control (C) group, and the TM group. Each pen was equipped with one bell drinker and four through feeders allocated side by side; all feeders of the C group contained a complete standard diet whereas each feeder of the TM group contained one of the following ingredients: ground corn, extruded semi-whole soybean, vitamin-mineral supplement mixture, and TM meal. Feed intake was recorded daily and growth was monitored periodically up to day 32. Chickens which had access to individual feed components showed a delay to display preference for TM, but consumed, overall, up to 50% of the total intake as TM meal. Feed intake and growth performance were lower in all periods for TM group (p < 0.02), whereas feed conversion ratio was improved on days 22-28 and days 29-32 of age (p < 0.01). Data from bivariate and multidimensional analysis indicate that birds started to reach a balance of ingredient intake at 25 days of age, showing a high correlation between consumption of each ingredient and the day of the experiment. Chickens exhibited a preference for T. molitor meal, resulting in improved feed efficiency, which allows us to conclude that it can be a suitable feed alternative for poultry.
RESUMO
This experiment was conducted to evaluate the combined effects of manganese-amino acid complex and arginine supplementation on the immune competence of broilers. On the day of hatch 640 male Cobb 500 broiler chicks assigned to two study groups (immune stimulate and non-stimulated). A 2 × 2 factorial arrangement of treatments was used with two manganese sources (MnSO4 or manganese-amino acid complex - MnAA) and two digestible Arg:Lys ratios (1.12 or 1.20). The treatments are: IM (80 ppm MnSO4); MnAA (40 ppm MnSO4 + 40 ppm MnAA); IM+Arg: 80 ppm MnSO4+ L-Arg (Arg:DigLys 1.20); MnAA+Arg: 40 ppm MnSO4 + 40 ppm MnAA + L-Arg (Arg:Lys 1.20). For treatments 1 and 2, the digestible Arg:Lys ratio was 1.12, considered normal for corn-soybean meal-based diets. Birds in the immune stimulated group received a dose of Salmonella Enteritidis vaccine. For growth performance and lymphoid organ development, no significant results were observed. Non-stimulated birds fed diets with Arg supplementation had higher percentage of mucosal T helper, T helper and T cytotoxic, compared to the normal Arg:Lys ratio (1.12). In the immune stimulated birds, broilers fed exclusive IM diet had a higher amount of T helper, T cytotoxic, activated T cytotoxic, and APC cells compared to broilers fed MnAA. The inorganic Mn diets, resulted in higher humoral antibody level (increased IgM levels) only when associated with supplementation of L-Arg. However, the use of an associated Mn source, could support high levels of IgM in commercial levels of Arg. No differences were observed to macrophage phagocytic activity analyses.
