Avaliação de probiótico para frangos de corte e probiótico e cromo orgânico para poedeiras

Abstract

The present study evaluated commercial probiotics, composed of microorganisms from Bacillus, and their effects on the productive performance, egg quality, and serum biochemistry of layer breeders, as well as growth performance and fecal microbiota of broiler chickens. For this, two experiments were performed in the Poultry Science Laboratory at Federal University of Santa Maria. In experiment I, the objective was to evaluate the effects of using Bacillus subtilis PB6 (2.0 x 1011 CFU/g), chromium propionate, or a combination of both on performance, egg and eggshell quality, nutrient metabolizability, and serum biochemistry of layer breeders. Sixty-four hens of Rhodes Island Red (n = 32) and Plymouth Rock White (n = 32) at 55 weeks of age, housed in individual cages in a conventional laying house, were used. Birds were distributed in a randomized block design, with 4 treatments and 16 replicates, with birds used as the experimental unit. The diets were: control; control + probiotic (supplemented with B. subtilis, 500g/ton); control + CrProp (chromium propionate, 50g/ton); control + B. subtilis + CrProp (supplemented with both additives). Productive parameters and eggshell quality as well as biochemical parameters and serum cortisol, were grouped into periods of 28 days each and from 55 to 70 weeks. Nutrient and energy metabolizability were determined at 70 weeks of age. Data were submitted for analysis of variance using the SAS GLM procedure, and when significant, means were compared by the Tukey test (P<0.05). In the total period, hens fed the control + probiotic or control + probiotic + CrProp diets had greater egg production, egg mass, shell percentage, shell thickness, and shell strength (P<0.05). The metabolizability of dry matter, nitrogen, and energy was higher in hens fed the control + probiotic + CrProp (P<0.05). In conclusion, the diet probiotic + CrProp supplementation for layer breeders from 55 to 70 weeks increased the digestibility of nutrients and improved the productive performance and egg quality. In experiment II, a probiotic B. subtilis BS-009, BS-020, and BS-024 (5 x 1011 spores/g) was evaluated, compared to an antibiotic growth promoter. A total of 750 male Cobb 500 1-day-old chicks were distributed to 5 treatments, with 6 replicates of 25 birds. The treatments were: Negative control (basal diet without additives or challenge); Challenged positive control (CP) and supplemented with 0.2 kg/ton of probiotic; CP + 0.3 kg/ton of probiotic; CP + 0.4 lg/ton of probiotic and CP + 0.025 kg of flavomycin/ton. At 14 days, broilers of challenged treatments received a commercial cocci vaccine (10x dose). On day 19, birds were orally gavaged with 1 mL/bird of Clostridium perfringens (3.1 x 109 cfu/mL). O day 5 and 25, excreta were collected for microbiome analysis. Growth performance was evaluated weekly until day 42. There was no significant difference in performance variables between treatments. However, there was an increase in the diversity of fecal microbiota for acidic bacteria and Clostidiales at 5 and 25 days. Therefore, probiotic supplementation contributed to maintain performance and for the beneficial composition of microbiota in broilers. In conclusion, probiotics from different B. subtilis strains contributed to improve performance and egg quality of laying hens as well as microbiome of broiler chickens.