LAUSR

Abstract Enteric methane production from ruminants contributes to current global warming challenges faced by mankind. Supplements that improve nutritive value of diets are potential mitigating strategies that may reduce enteric methane emissions. This study was, therefore, designed to evaluate the potential of duckweed (Lemna gibba) supplement to reduce enteric methane emissions using an in vitro ruminal gas production technique. In the first of two experiments, Lemna gibba from two water bodies (LG1 and LG2), lucerne and ryegrass samples were analyzed for chemical composition and in vitro ruminal fermentation parameters. In the second experiment, the two Lemna gibba samples were each included in a basal diet at 5, 10, 15, 20 and 25% to create ten dietary treatments. The dietary treatments were also analyzed for chemical composition and in vitro ruminal fermentation characteristics as in the first experiment. Lemna gibba and lucerne fermentation resulted in similar propionate levels. The inclusion of 15% L. gibba had no effect on the ruminal fermentation patterns (volatile fatty acids, acetate:propionate ratio, acetate, propionate and butyrate) and the dry matter and organic matter degradability. These results indicate that L. gibba could be used in ruminant diets as an alternative to grains or concentrates with the added advantage of possibly reducing ruminal methane emissions. Dietary supplementation with L. gibba in ruminant diets could be an environmentally friendly strategy to reduce feed costs and ensure sustainable production.