The effect of dietary Chlorella vulgaris supplementation on micro‐organism community, enzyme activities and fatty acid profile in the rumen liquid of goats

Abstract

Microalgae might be considered as an alternative source of fat and/or protein for ruminant's diets. However, changes in populations of ruminal micro-organisms associated with biohydrogenation process, methane and ammonia production in response to microalgae dietary supplementation have not been well characterized. Thus, 16 cross-bred goats were divided into two groups. Each goat of both groups was fed individually with alfalfa hay and concentrates separately. The concentrates of the control group had no microalgae while those of the treated group were supplemented with 10 g lyophilized Chlorella vulgaris/kg concentrate (chlor). On the 30th experimental day, samples of rumen fluid were collected for microbial DNA extraction, fatty acid profile and enzyme activity analyses. The results showed that the chlor diet compared with the control increased significantly the populations of Methanosphaera stadtmanae, Methanobrevibacter ruminantium and Methanogens bacteria and protozoa in the rumen of goats. A significant reduction in the cellulase activity and in the abundance of Ruminococcus albus, and a significant increase in the protease activity and in the abundance of Clostridium sticklandii in the rumen liquid of goats fed with the chlor diet, compared with the control, were found. Chlorella vulgaris supplementation promoted the formation of trans C , trans-11 C and monounsaturated fatty acids (MUFA), while the proportions of C and long-chain fatty acids (LCFA) reduced significantly in the rumen liquid of goats. This shift in ruminal biohydrogenation pathway was accompanied by a significant increase in Butyrivibrio fibrisolvens trans C -producing bacteria. In conclusion, the supplementation of diets with microalgae needs further investigation because it enhances the populations of methane-producing bacteria and protozoa.

The effects of three total mixed rations with different concentrate to maize silage ratios and different levels of microalgae Chlorella vulgaris on in vitro total gas, methane and carbon dioxide production

“…Tsiplakou et al . (2016) observed an increased methanobacteria and protozoa population in the rumen liquid of goats fed a forage-based diet supplemented with C. vulgaris . Anele et al .…”

“…Besides this, and due to its high eicosapentaenoic and docosahexaenoic (DHA) contents, C. vulgaris has been considered as a possible additive for reduction of CH 4 emissions (Tsiplakou et al . 2016). This may be related to its content of unsaturated fatty acids, resulting in reduced CH 4 production (Martin et al .…”

“…However, Tsiplakou et al . (2016) reported that microalgae rich in protein and low in fat content increased the populations of CH 4 -producing bacteria and protozoa.…”

Variability of in vitro ruminal fermentation and nutritional value of cell‐disrupted and nondisrupted microalgae for ruminants

“…(2017a) observed an increase in methane production and Tsiplakou et al. () observed an increase in methane‐producing bacteria and protozoa with the supplementation of protein‐rich Chlorella vulgaris , indicating that not all microalgae are likely to have methane reducing properties. Data on methane production in this study showed a similar trend.…”

“…Several authors have reported a reduction of ruminal methanogenesis in vitro (Boeckaert et al, 2006;Fievez et al, 2007;Ungerfeld, Rust, Burnett, Yokoyama, & Wang, 2005) or in vivo (Elghandour et al, 2017) when microalgae rich in polyunsaturated fatty acids (docosahexaenoic acid, hexadecatrienoic acid) were supplemented. Nevertheless, Kholif et al (2017a) observed an increase in methane production and Tsiplakou et al (2016) observed an increase in methane-producing bacteria and protozoa with the supplementation of protein-rich Chlorella vulgaris, indicating that not all microalgae are likely to have methane reducing properties. Data on methane production in this study showed a similar trend.…”