RESUMO
This study evaluated the effect of Candida norvegensis (C. norvegensis) viable yeast culture on in vitro ruminal fermentation of oat straw. Ruminal fluid was mixed with buffer solution (1:2) and anaerobically incubated with or without yeast at 39°C for 0, 4, 8, 16, and 24 h. A fully randomized design was used. There was a decrease in lactic acid (quadratic, p = 0.01), pH, (quadratic, p = 0.02), and yeasts counts (linear, p<0.01) across fermentation times. However, in vitro dry matter disappearance (IVDMD) and ammonia-N increased across fermentation times (quadratic; p<0.01 and p<0.02, respectively). Addition of yeast cells caused a decrease in pH values compared over all fermentation times (p<0.01), and lactic acid decreased at 12 h (p = 0.05). Meanwhile, yeast counts increased (p = 0.01) at 12 h. C. norvegensis increased ammonia-N at 4, 8, 12, and 24 h (p<0.01), and IVDMD of oat straw increased at 8, 12, and 24 h (p<0.01) of fermentation. Yeast cells increased acetate (p<0.01), propionate (p<0.03), and butyrate (p<0.03) at 8 h, while valeriate and isovaleriate increased at 8, 12, and 24 h (p<0.01). The yeast did not affect cellulolytic bacteria (p = 0.05), but cellulolytic fungi increased at 4 and 8 h (p<0.01), whereas production of methane decreased (p<0.01) at 8 h. It is concluded that addition of C. norvegensis to in vitro oat straw fermentation increased ruminal fermentation parameters as well as microbial growth with reduction of methane production. Additionally, yeast inoculum also improved IVDMD.
RESUMO
Abstract The objective of this study was to evaluate the efficacy of oral sodium chlorate administration on reducing total coliform populations in ewes. A 30% sodium chlorate product or a sodium chloride placebo was administered to twelve lactating Dorper X Blackbelly or Pelibuey crossbred ewes averaging 65 kg body weight. The ewes were adapted to diet and management. Ewes were randomly assigned (4/treatment) to one of three treatments which were administered twice daily by oral gavage for five consecutive days: a control (TC) consisting of 3 g sodium chloride/animal/d, a T3 treatment consisting of 1.8 g of sodium chlorate/animal/d, and a T9 treatment consisting of 5.4 g sodium chlorate/animal/d; the latter was intended to approximate a lowest known effective dose. Ruminal samples collected by stomach tube and freshly voided fecal samples were collected daily beginning 3 days before treatment initiation and for 6 days thereafter. Contents were cultured quantitatively to enumerate total coliforms. There were no significant differences in total coliform numbers (log10 cfu/g) in the feces between treatments (P = 0.832). There were differences (P < 0.02) in ruminal coliform counts (log10 cfu/mL) between treatments (4.1, 4.3 and 5.0 log10/mL contents in TC, T3 and T9 Treatments, respectively) which tended to increase from the beginning of treatment until the 5th day of treatment (P < 0.05). Overall, we did not obtain the expected results with oral administration of sodium chloride at the applied doses. By comparing the trends in coliform populations in the rumen contents in all treatments, there was an increase over the days. The opposite trend occurred in the feces, due mainly to differences among rumen contents and feces in ewes administered the T9 treatment (P = 0.06). These results suggest that the low chlorate doses used here were suboptimal for the control of coliforms in the gastrointestinal tract of ewes.
