The use of condensed tannin in lambs' diet alters the rumen protozoa population without affecting growth performance

Abstract

The aim of this study was to evaluate the effect of different doses of Black Wattle (Acacia mearnsii) condensed tannin on performance, dry matter intake, blood parameters, and identification and quantification of the rumen protozoa population at fasting and after feeding of feedlot lambs. Sixteen Santa Ines intact ram lambs and sixteen Santa Ines ewe lambs were distributed and randomly assigned to 1 of 4 dietary treatments with different doses of condensed tannin (0 %, 1 %, 2 %, and 3 %) in the concentrate, on a feedlot system. No significant treatment effect (P > 0.05) was observed for growth performance, dry matter intake, and blood parameters. No significant effects of treatment (P > 0.05), phase (fasting and after feeding) (P > 0.05), and interaction between treatment and phase (P > 0.05) were observed for total and differential protozoa percentage. However, differences were observed for total and differential protozoa count. A quadratic effect (P = 0.03) was observed for total counts of Diplodiniinae in the rumen fluid of animals fed 3 % of condensed tannin. A phase effect was observed for counts of Isotricha spp, Entodinium spp. Diplodiniinae, and total protozoa count with higher numbers observed at fasting when compared to after feeding. Results of this research suggest that up to 3 % of black wattle condensed tannin in the diet of lambs does not affect dry matter intake, animal performance, and blood parameters.