Browsing by Subject "gas in vitro"

Increased greenhouse gases (CH4, CO2 and N2O) have warmed the Earth's climate over the last decades. Feeding, feed additives and livestock breeding have been offered as solutions for reducing methane emission from livestock. Ruminant’s ability to use high-fiber feeds is based on microbial fermentation in rumen resulting methane production. Objective of the study was to find out if dwarf birch leaves reduce methane production in vitro and predicted in vivo production. Dwarf birch (Betula nana) leaves contain tannins and essential oils that can reduce methane production. Hypothesis was that dwarf birch reduces methane production. Silver birch (Betula pendula) leaves were used as comparison. Silver birch’s tannin concentration is only a fraction of the dwarf birch’s tannin concentration. Birch leaves increased the in vitro methane production moderately. As the incubation level increased the molar proportion of propionic acid increased linearly. Birch leaf treatment decreased the molar proportion of acetic acid. Acetate:propionate ratio decreased with birch leaf treatment and with increased incubation level. Birch leaf treatment and higher incubation level decreased sample pH. Birch leaf treatment or higher incubation level did not affect to the predicted in vivo methane production, but increased the total gas production. Thus, birch leaf treatment decreased predicted in vivo methane’s proportion of total gas significantly. Based on regression analysis, VFA production was elevated with higher incubation level of Silver birch leaves, indicating increased fermentation. Changes in methane production and VFA proportions were likely caused by birch leaf tannins and essential oils. Acidity of birch leaves and the reduction in buffer capacity of rumen fluid affected to samples pH. Tannins, essential oils and decrease in pH could reduce the feed digestibility or activity of the methanogenic archaea. Because of that part of the hydrogen was released into the air without being converted to methane.