In Vitro Screening of the Foliage of Eucalyptus Species Harvested in Different Seasons for Modulating Rumen Fermentation and Methane Production

Abstract

The aim of this study was to assess the effects of five eucalyptus species (Eucalyptus camaldulensis, E. leucoxylon, E. astringens, E. sideroxylon, and E. lehmannii), harvested in spring, autumn, or winter from two Tunisian arboretums, on in vitro rumen fermentation and methanogenesis. Batch cultures were performed to determine rumen fermentation kinetics and end-product formation after 24 h of incubation. The foliage of the species E. sideroxylon and E. lehmannii showed the greatest digestibility coefficients, whereas E. leucoxylon was the least digestible. Acetate-to-propionate ratio was reduced when E. sideroxylon and E. lehmannii were incubated, and these species were also the most efficient at reducing methane emission. Foliage harvested in winter showed greater digestibility and an increase in the acetate-to-propionate ratio than in other seasons, without an increase in methane emission. Foliage from E. sideroxylon and E. lehmannii showed a potential to decrease enteric methane production without depressing effects on ruminal fermentation. In vivo studies would be necessary to conclusively validate these effects as the first step towards proposing the inclusion of eucalyptus leaves in ruminant diets.

Seasonal Variation in Chemical Composition, Ruminal Fermentation, and Biological Characteristics of Paulownia shan tong: In Vitro Potential Use by Sheep and Goats

“…Leaves from the spring harvest showed higher concentrations of OM, lipids, NDF, ADF, and ADL (Table 1). Other studies carried out in the literature [17,32] pointed out the significant effect of the harvest time on the nutrient concentrations of plants. The environmental conditions and maturation state are the main factors that influence the chemical composition of plants [33,34].…”

“…Different ruminant species have different comparative abilities to digest feeds; therefore, examining the fermentative capacity of the same feed with microbial populations from sheep and goats is important. Furthermore, the harvesting season dramatically affects the nutritive value of plants [17]. Horst et al [17] observed that the digestibility and the acetate-to-propionate ratio of eucalyptus foliage were higher during the winter than during autumn and spring without affecting methane emissions.…”

“…Furthermore, the harvesting season dramatically affects the nutritive value of plants [17]. Horst et al [17] observed that the digestibility and the acetate-to-propionate ratio of eucalyptus foliage were higher during the winter than during autumn and spring without affecting methane emissions. Thus, the hypothesis of the present study is that different relationships exist between the nutritional value of Paulownia feed materials harvested during two different seasons as well as their content of secondary metabolites, which may impact their in vitro gas production (GP) and digestibility.…”