Rumen responses to dietary supplementation with cashew nut shell liquid and its cessation in sheep

Abstract

Rumen responses to cashew nut shell liquid (CNSL) were evaluated in a feeding study. Four wethers were fed a hay and concentrate diet for 4 weeks (pre-CNSL period), and then fed the same diet supplemented with low and high levels of CNSL for 2 weeks each (L-CNSL and H-CNSL periods respectively). The diet was then reverted to the unsupplemented control diet for another 2 weeks (post-CNSL period). Rumen parameters were monitored in each feeding period. CNSL, regardless of the two levels tested, did not show any adverse effects on total short chain fatty acid concentration and dry matter digestibility in the rumen. Propionate proportion increased in the H-CNSL period, while methane production potential, acetate and butyrate proportions, viscosity, foam formation and its stability, and ammonia concentration decreased. Values of these parameters returned to those in the unsupplemented control period after cessation of CNSL supplementation. Clone library analysis of 16S rRNA genes revealed the following shifts in the H-CNSL period. For bacteria, Firmicutes was frequently detected, while Bacteroidetes and Spirochetes were not. For archaea, Methanobrevibacter wolinii was predominant. These results indicate that CNSL could be a methane inhibitor and propionate enhancer by altering the rumen microbial community.

Feeding cashew nut shell liquid decreases methane production from feces by altering fecal bacterial and archaeal communities in Thai local ruminants

“…Fermentation parameters changed as well in animals fed CNSL, with less acetate and more propionate production among SCFAs and less gas production, particularly methane (83.2% decrease in native cattle and 74.5% decrease in buffaloes, Table 2). These results are in good agreement with reports of fermentation changes in the rumen of local Thai ruminants (Konda et al., 2019), Japanese Holsten cows (Shinkai et al., 2012), and sheep (Kang et al., 2018) fed CNSL. Thus, our findings demonstrate that CNSL feeding alters not only rumen fermentation but also hindgut fermentation, as observed in fresh feces of the present study.…”

Microbial community structure of the bovine rumen as affected by feeding cashew nut shell liquid, a methane‐inhibiting and propionate‐enhancing agent

“…yield of dairy cows (Coutinho et al, 2014). Such favorable fermentation changes also have been reported in sheep (Kang et al, 2018) and local ruminants, including Thai native cattle and swamp buffaloes (Konda et al, 2019). At the same time, some reports have failed to observe a strong impact of CNSL on rumen microbes and fermentation (Branco et al, 2015).…”

The bio‐surfactant mannosylerythritol lipid acts as a selective antibacterial agent to modulate rumen fermentation

“…Thus, responses to MEL addition and removal were rapid, and did not have any residual influence on fermentation parameters. This is an ideal characteristic of a feed additive, as observed for the similar surfactant additive, cashew nut shell liquid (Kang et al, 2018). In the meantime, persistence of the favorable effects of MEL requires clarification, as the above favorable fermentation changes were observed up to the 3rd week of the MEL feeding period (Table 4).…”

“…). Rumen physical parameters including viscosity, ingesta volume index (IVI), and stable ingesta volume index (sIVI) were determined according toKang et al (2018). Quantitative PCR (qPCR) for representative rumen bacterial species was carried out according to Watanabe et al (2010) using samples taken before feeding.…”