Effect of oral dosing of live and autoclaved culture of Ruminococcus flavefaciens FD-1 on rumen bacterial and fungal populations in Murrah buffaloes

Abstract

Dietary interventions aiming at increasing the number and activities of beneficial gut microbes could enhance digestive functions as well as the long-term welfare of dairy animals. In the present experiment, the effect of supplementation of a novel bacterial culture Ruminococcus flavefaciens FD-1 isolated from the rumen liquor of Murrah buffaloes was studied for its effect on rumen microbial populations enumerated using the most probable number technique. Three permanently fistulated buffaloes maintained on a high fibre diet were used as the source of rumen fluid for bacterial isolation that was subsequently tested in vivo. Twelve healthy mid-to-late lactating buffaloes in their second to third parity were divided into two similar groups of six each with a mean body weight of 601.5 kg. One group (LBC) was dosed with 300 mL of live bacterial culture, whereas an equal volume of autoclaved bacterial culture was dosed in another group (ABC) for a period of one month. The treatment-wise effect of supplementation of R. flavefaciens FD-1 culture was evident in an increase (P<0.05) in total rumen fungal population by 2.7 times in LBC than ABC in the post-dosing period. However, the period-wise comparison revealed that the population of bacteria augmented (P<0.05) by 2.16 and 3.17 times in both the groups ABC and LBC, respectively; whereas the magnitude of increase in fungal population was 5.04 and 10.3 times, respectively for both the groups. Post-dosing effects were evident for only group LBC in both bacteria and fungi, respectively increasing (P<0.05) the population by 2.16 and 8.28 times than pre-dosing period. These preliminary results may foster scope for developing species-specific (autochthonous) bacterial probiotic/direct-fed microbial based on R. flavefaciens FD-1 for large ruminants maintained on fibrous diets under tropical production systems.

Research progress in isolation and identification of rumen probiotics

“…However, the number of rumen probiotics in the traditional culture strategy is limited, and the growth and metabolic characteristics of many rumen microorganisms are still unclear, which hinders the systematic study of rumen microorganisms. Currently, selective culture media among probiotics include Bifidobacterium selective medium, Lactobacillus selective medium, low carbon-resistant selective medium, and sodium carboxymethylcellulose, etc ( Kumar et al, 2021 ; Jaglan et al, 2019 ; Kuppusamy et al, 2020 ). The addition of antioxidants (ascorbic acid, glutathione, and uric acid in the culture medium) enhances the culture of anaerobic bacteria ( Tidjani Alou et al., 2020 ); It can also use the rumen fluid to simulate the natural environment of certain bacteria to promote their growth ( Bonnet et al., 2019 ).…”

“…Hu et al ( 2022) used the roll-tube technique to isolate Streptococcus equinus, Enterococcus avium, and Streptococcus lutetiensis, which have inhibitory effects on Escherichia coli and Staphylococcus aureus, from the rumen juice of Holstein cows as potential probiotics or silage inoculants. Kumar et al (2021) screened three strains of cellulose-degrading rumen-producing Ruminococcus flavefaciens from buffalo rumen fluid by dispensing carboxymethylcellulose medium in Heinz tubes, and subsequent animal experiments showed that Ruminococcus flavefaciens significantly increased the number and activity of beneficial gut microorganisms and enhanced the digestive function of milk-producing buffaloes. Droplet-based high-throughput culture (Tan et al, 2020;Anggraini et al, 2022;Yin et al, 2022;Zhao et al, 2016).…”