Influence of low doses tannins extract addition on the presence of Escherichia coli in feces of beef cattle

Abstract Text:

Feces of twenty bulls 430 ± 4.5 kg (75% Brahman breed with remainder of Brown Swiss  or Charolais) fed finishing diets were used to determine the influence of Influence of low doses tannin extract addition on the presence of Escherichia coli in feces of beef cattle. From each of four commercial feedlot pens containing 70 bulls, five bulls were randomly selected and moved to squeeze and fecal samples were taken. Feces of five bulls from a common pen were pooled and constitute the experimental unit. Pooled fecal sample were divides in four portions of proximately 60 g (wet basis), one portion was used for DM determination, and remainder three fecal samples by pen were randomly assigned for addition or not tannins extract (TE) as follows: 1) Feces without extra addition (Control); 2) Control plus 0.1008 g of condensed tannins extract (CTE); and 3) Control plus 0.1008 g of hydrolysable tannins extract (HTE). TE was fed as SilvaTeam® (Argentina). Feces was thoroughly mixed and placed on piece of Kraft paper underground 0.70 m outside of pen and covered with a 0.4 x 0.4 x 0.25 cm metal mesh cage, and exposed to feedlot environment during 0, 24, 48 or 72 h. Aliquots from each TE schedule, exposed time and pen were taken, and by triplicate placed in a E. coli selective medium and incubated during 24 h at 45 °C, after incubation Colonies Former Units (CFU) were counted and transformed to log₁₀CFU. Results were analyzed by ANOVA for a completely randomized design with a 3 x 4 factorial arrangement. Feces DM were 27.27%, and then TE dose was 0.6% of fecal DM. At 0 h, E. coli presence was 4.19, 4.08, and 4.28 log₁₀CFU for Control, CTE and CTH, respectively. At 48 h CTE tended (P = 0.07) to decrease E. coli presence compared with 0 h (4.08 vs. 1.13 log₁₀CFU). At 72 h CTE tended to diminished (P = 0.07) E. coli in bovine feces with means values of 4.07, 3.22 and 1.76 log₁₀CFU for Control, CTE and HTE, respectively. It is concluded; that the addition of condensed tannin extract at very low concentration could contributes to reduce the Escherichia coli population in the feces of feedlot cattle.

Keywords: Escherichia coli, Bovines, Tannins extract.