Aditivos fitogênicos na terminação de tourinhos nelore confinados

• Autor(a) principal: Moreira, Kíria Karolline Gomes
• Data de Publicação: 2018
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/8773
• topic: Barbatimão; Extrato de plantas; Monensina; Nelore; Monensin; Nellore; Plants extracts; Tannins; CIENCIAS AGRARIAS::ZOOTECNIA

Phytogenic additives with action similar to ionophores can be used as alternatives to synthetic additives. Two experiments were carried out to evaluate the effects of phytogenic antimicrobial additives on performance, carcass characteristics, nutrient digestibility and ruminal metabolic profile of Nellore bulls feedlot. In the first experiment, 114 Nellore steers (335.48 ± 25.70 kg) were assigned to a randomized complete block design with 4 treatments: monensin; S. Adstrigens extract; essential oils blend; functional oils cashew, castor and copaiba on the growth performance and carcass. The diet consisted of 19.49% sugarcane bagasse and 80.51% concentrate (DM basis). DMI of animals receiving monensin (104 days feedlot) was 16.2% lower than the animals that consumed dry extract and 8.6% lower than the animals that received functional oils (P <0.001). Animals that consumed dry extract of S. adstrigens showed higher consumption of NDF (P <0.001). FBW (μ = 485.60 kg) and ADG (μ = 1.42 kg/d) were not affected by treatments (P>0.05). FE was better (P <0.05) for MON (0.184 kg/kg) than BBT and MOE. There was no difference (P>0.05) for carcass characteristics. The use of phytogenic additives in feed of confined cattle did not influence the carcass characteristics, but the use of monensin still provides better performance results. In the second experiment, was to evaluate the characteristics of ruminal fermentation and digestibility of nutrients of a finishing diet with phytogenic additives. Five fistulated steers (initial BW = 275.40 ± 15.53 kg) were used in a 5 × 5 Latin Square design. Treatments were: no additive; monensin 30 mg/kg DM; extract of S. adstrigens 1.500 mg/kg DM; mixture of essential oils 118 mg/kg DM; mixture of functional oils from cashew, castor, and copaiba 250 mg/kg DM. The diet consisted on DM basis of 19.49% of sugarcane bagasse and 80.51% of concentrate with corn, soybean meal, urea and minerals. There were no effects (P>0.05) on nutrients intake, apparent digestibility concentration of VF, acetate:propionate ratio and concentration of NH3-N. Steers fed mixture of functional oils showed higher ruminal pH (6,75) than BBT (6,54; P <0.05). Phytogenic additives have the potential to replace synthetic antibiotics without penalizing the productive system of beef cattle.