Effect of humic acid on fermentation and ciliate protozoan population in rumen fluid of sheep in vitro
2009
Váradyová, Zora | Kišidayová, Svetlana | Jalč, Dušan
BACKGROUND: Humic acid (HA) as a product of decomposition of animal and plant tissue is used in animal production as a feed supplement, antimicrobial product and growth stimulator. The objective of the present in vitro study was to investigate the effects of dietary humic acid as a commercial Humacid 60 Basic (H60B) feed additive preparation on rumen fermentation and the ciliate protozoan population in the rumen fluid of sheep using a high fibre (HF) and high concentrate (HC) diet in batch cultures and artificial rumen (RUSITEC).RESULTS: Production of total volatile fatty acids (VFAs) was significantly decreased (P < 0.001) for batch cultures by the HF-H60B diet. The HF-H60B diet decreased ammonia N in RUSITEC (P < 0.001). An increase in the population of Enoploplastron triloricatum, Isotricha spp. and Ophryoscolex c. tricoronatus with the HF-H60B diet and Diploplastron affine with the HC-H60B was observed. The H60B did not affect the total ciliate population and Entodinium spp.CONCLUSION: It can be concluded that dietary humic acid preparations are not effective as dietary antiprotozoal agents. Humic acid might enhance microbial growth and energy efficiency in doses up to 10 g kg⁻¹ DM of diet.
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