Influence of a dried Bacillus subtilis culture on intestinal microflora and performance of broilers and turkeys

Two experiments, each involving a 3 x 2 factorial design, were conducted with Large White turkeys to determine the influence of a Bacillus subtilis culture on body weight gain (BWG), feed efficiency (FE), livability and intestinal microflora. Four experiments with broiler chickens were also conducted to evaluate the protein-sparing effect of the B. subtilis culture when fed with different levels and sources of protein. The protease activity of the culture was hypothesized to improve protein digestibility. In the first experiment with female turkeys, the culture increased (P $\u3c$.01) B. subtilis counts in the crop and cecum, but failed to influence (P $\u3e$.05) Lactobacillus or Escherichia coli counts in the crop, jejunum and cecum. Feeding the B. subtilis culture did not significantly affect BWG and FE. However, two antibiotic supplements (44 ppm of Zn bacitracin or 44 ppm of penicillin-streptomycin) did increase BWG at 12 (P $\u3c$.05) and 16 (P $\u3c$.001) wk. In the second experiment, turkeys receiving the B. subtilis culture had greater (P $\u3c$.01) BWG at 12 wk, and improved (P $\u3c$.05) FE at 20 wk. Livability of turkeys receiving the culture was 3.8 and 1.4% higher in Experiments 1 and 2, respectively. The protein requirement of broiler chickens was apparently spared in Experiments 1 and 2 when B. subtilis was fed in low protein diets containing 5% meat and bone meal. Birds receiving low protein diets supplemented with the culture had increased (P $\u3c$.05) BWG and carcass weights, and improved (P $\u3c$.05) FE as compared to controls. When the culture was fed in the presence of increasing levels of poultry by-product meal (PBM) and feather meal (FM) in broiler diets (Experiments 3 and 4), BWG and FE were not affected (P $\u3e$.05). However, when the highest levels of PBM and FM (9.0 and 4.5%, respectively) were fed, addition of the bacterial culture resulted in a numerical increase in BWG and a similar improvement in FE. Livability was greater among birds receiving the B. subtilis in all four broiler experiments, which is consistent with results of the turkey experiments

Uso de probiótico e antibiótico sobre o desempenho, o rendimento e a qualidade de carcaça de frangos de corte Effect of the use of probiotic and antibiotic on the performance, yield and carcass quality of broilers

Dois mil e quatrocentos pintos de corte foram distribuídos em um delineamento inteiramente ao acaso, com esquema fatorial 2 x 2 x 2 (sexo, com e sem probiótico, com e sem antibiótico), totalizando oito tratamentos e seis repetições com 50 aves cada uma. Independente da suplementação recebida, os machos sempre foram mais pesados que as fêmeas. Entretanto, a análise de desempenho apresentou maiores peso corporal e ganho de peso para os machos que receberam suplementação de antibiótico, quando comparados aos não-suplementados. Até 42 dias de idade, o uso do antibiótico determinou aumento do consumo de ração, mas não influiu nas demais características de desempenho. No período de 1 a 21 dias e 1 a 42 dias de idade, a suplementação com probiótico influenciou negativamente o peso corporal, ganho de peso e consumo de ração das aves. Houve interação probiótico x antibiótico para rendimento de carcaça das aves, obtendo-se maior rendimento de carcaça com o uso da associação dos produtos na ração. Nenhum dos produtos afetou o rendimento de partes (cabeça, pés, asas, perna, peito e dorso), o rendimento de vísceras (coração, fígado e vísceras não-comestíveis), gordura abdominal e características sensoriais (intensidade de aroma, aroma estranho, sabor, sabor estranho, maciez, suculência, preferência, cor característica e aparência geral) da carne de peito e pernas. No presente estudo, não foram encontrados efeitos benéficos da suplementação de probiótico para frangos de corte.<br>Two thousand and four hundred broiler chicks were assigned to a completely randomized design in a 2 x 2 x 2 (sex, with and without probiotic, with and without antibiotic) factorial arrangement, totalizing eight treatments and six replicates with 50 birds in each one. Independently of supplementation fed, the males were always heavier than the females. However, the analyses performance showed higher body weight and weight gain for males fed antibiotic when compared to the non supplemented. The use of antibiotic increased feed intake up to 42 days of age, but it did not affect the other characteristics. Probiotic supplementation negatively influenced the body weight, weight gain and feed intake of the broilers from either 1 to 21 or 1 to 42 days of age. There was a probiotic x antibiotic interaction for carcass yield of the broilers, and the highest carcass yield were obtained when the products were associated in the diet. Neither probiotic nor antibiotic affected cut-part yield (head, feet, wings, leg, breast and back), viscera yield (heart, liver and non edible viscera), abdominal fat and sensorial characteristics (intensity of aroma, stranger aroma, flavor, stranger flavor, tenderness, juiciness, acceptability, characteristic color and overall aspect) of breast and leg meats. No beneficial effects of the probiotic supplementation in broiler diets were observed in the present study