Gas Production Kinetics, Organic Matter Digestibility and Methane Production in Vitro in Hay and Straw Diets Supplemented by Tannin-Containing Forages

Abstract

This research was aimed to evaluate supplementation of tannin-containing forages, namely Rhus typhina and Salix alba into hay and straw diets on rumen fermentation parameters in vitro, especially on methane production. Supplementation was applied at 30% dry matter replacement from hay and straw diets. Treatments consisted of: H (hay), J (straw), RT (R. typhina), SA (S. alba), H:RT (hay:R. typhina, 70:30), H:SA (hay:S. alba, 70:30), J:RT (straw:R. typhina, 70:30), and J:SA (straw:S. alba, 70:30). Incubation was applied using Hohenheim gas production method for 24 hours. Variables measured after incubation were cumulative and kinetics of gas production, methane emission and organic matter digestibility. The results showed that supplementation of R. typhina and S. alba decreased (P<0.05) percentage of methane production by 11.2% and 4.3% when added to hay, respectively; while it decreased (P<0,05) percentage methane production by 15.8% and 6.1% when added to straw, respectively. Additionally, supplementation of these tannin-containing forages signifi cantly increased (P<0.05) organic matter digestibility of hay and straw. It was concluded that supplementation of tannin-containing forages could strategically be used to decrease methane emission from rumen fermentation in vitro, and at the same time increase the quality of basal diets.