Effect of different levels of zinc oxide nano particles and zinc oxide on some ruminal parameters by in vitro and in vivo methods

In this study the effects of zinc oxide (ZnO) and zinc oxide nano particles (nZnO) were investigated on some parameters of rumen with either in vitro or in vivo experiments based on a completely randomized design. The experimental treatments (5 treatments) were included levels of zero (control), 20 and 40 ppm zinc as ZnO and 20 and 40 ppm zinc as nZnO that were added to the basal diets. In in vitro experiments, rumen fermentation kinetics parameters during 144 h continuous incubation (GP144) and the volume of gas produced during the 24 h incubation (GP24) and the relevant fermentation parameters were analyzed separately. In in vivo experiments, 20 male Markhoz goat kids aged 7-8 months were fed for 14 days with experimental treatments and the pH, ammonia and total volatile fatty acids concentration and protozoa populations in rumen fluid were determined. Results showed, GP144 and GP24 and the relevant parameters (except for asymptotic gas production (A) and lag time (L)) and rumen parameters in in vivo experiment were not affected by zinc sources. No significant difference was observed between treatments for total number of protozoa. Highest number was seen for Entodinium spp. and lowest for Isotricha spp.. Overall, the levels of 20 and 40 ppm zinc as ZnO and nZnO had no effect on rumen parameters by either in vitro or in vivo methods.