Protozoários ciliados (Protista, Ciliophora) no rúmen de novilhos recebendo dieta com monensina ou própolis

Abstract

The ciliated protozoa are part of the rumen microbial and together with bacteria, fungi and flagellate protozoa play important biochemical and physiological functions for ruminants, especially in the metabolism of nutrients. However, its role in the rumen yet is not entirely clear, and it may bring both beneficial and harmful effects to animal production. This study aimed to characterize the ciliated protozoa population in the rumen of steers fed with diets containing monensin or products based on propolis LLOS, evaluating the impact of supplementation of these additives in a short period of time on the abundance of ciliates. Five steers, fistulated in the rumen and distributed in Latin square design (5X5) were fed with a diet consisting of 47% corn silage and 53% concentrate based on grinded corn and bran soybean. Diets were tested without additives (control), with the addition of monensin or products based on propolis LLOSB1+, LLOSC1+ and LLOSC1++. The samples of rumen contents were collected before the start of each sampling period (day 0) and 8, 15 and 21 days after the start of each sampling period, whereas, on each collect day were collected samples before the supply of experimental diet (0 h) and 3 and 6 hours later supplementation. The predominant genus in the diets was the Entodinium, representing a value above 97% of the total density of ciliates. The ciliate population in the rumen of steers were not altered by supplementation with the additive monensin or products based on propolis LLOS. Rumen pH changed only between times of sampling. The Entodinium population increased after 15 days of the products addition based on propolis LLOSB1+ and after 21 days it was observed a negative effect of this additive on the ciliates. They increased, returning to their initial levels. The ciliates got shorter after 8 days of monensina addition in the diet, reestablishing after 15 days of supplementation and getting shorter again at the end of the experiment. The genus Entodinium population throughout the experiment were altered during the experimental periods, especially with the addition of the products based on propolis LLOS which may have affected the results. It is therefore suggested, an increase of the experimental period and the replacement of the Latin square design in future works.