1. Effect of fibrolytic enzyme and oil supplementation on in vitro gas and methane production of total mixed ration
M. Booyse, A. Hassen
1 Department of Animal and Wildlife Science University of Pretoria, Pretoria, South Africa (
Introduction
Supplementation of oil in ruminant diets is one method of decreasing methane production. Enzymes are often added to ruminant feed to increase the digestibility of poor quality diets, but associated with this is an increase in methane production due to an increase in hydrogen ions. This increase in hydrogen concentration can possibly be compensated for by adding oil to the diet, as the double bonds in oil may serve as a hydrogen sink due to rumen hydrogenation. In this in vitro study a total mixed ration (TMR) was treated with a combination of enzyme and oil in order to assess their effect in terms of gas and methane production.
Methodology
Samples of total mixed ration were incubated with two types of oils (palm oil and canola oil) with or without fibrolytic enzyme application, were incubated for 48 hr using batch culture with buffer and ruminal fluid collected, strained and anaerobically prepared (1:4 ratios). The oils used were included at a level of 3% of the TMR. The enzymes used were a 1:1 ratio of xylanase and cellulase added at 1 mg/kg DM. The TMR was treated with fibrolytic enzymes 24hr before incubation. A semi-automated system was used to measure gas production.
Results
Table 1: Chemical composition of in vitro Total mixed ration (TMR)
Dry matter (%)
Ash
(%)
Crude protein (%)
Fat
Starch (g/kg)
NDF
(g/kg) ME
(MJ/kg DM)
Ca (%)
P (%)
88.7
6.9
13.3
5.8
236.1
308.6
10.1
0.9
0.3
Conclusion
Inclusion of palm oil significantly reduced methane emission, but the amount of methane reduction observed as a percentage of total gas production was not significantly different from the control.
Inclusion of fibrolytic enzymes has significantly decreased methane production.
Acknowledgements
The authors gratefully acknowledge funding from the Dept. of Science and Technology, IAEA and the European communities, 7th framework programme under the grant agreement No , ANIMALCHANGE project.
Climate smart conference, from March 2015, Montpellier, France