AUTHOR=Mohapatra Archit , Trivedi Shraddha , Kolte Atul P. , Tejpal Chaluvanahalli S. , Elavarasan Krishnamoorthy , Vaswani Shalini , Malik Pradeep Kumar , Ravishankar Chandragiri Nagarajarao , Bhatta Raghavendra 

TITLE=Effect of Padina gymnospora biowaste inclusion on in vitro methane production, feed fermentation, and microbial diversity

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1431131

DOI=10.3389/fmicb.2024.1431131

ISSN=1664-302X

ABSTRACT=<p><italic>In vitro</italic> studies were undertaken aiming to study the methane (CH<sub>4</sub>) mitigation potential of biowaste (BW) of <italic>Padina gymnospora</italic> at the graded inclusion of 0% (C), 2% (A<sub>2</sub>), 5% (A<sub>5</sub>), and 10% (A<sub>10</sub>) of the diet composed of straw and concentrate in 40:60 ratio. The chemical composition analysis revealed that the BW contained higher crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and ether extract (EE) than the PF (fresh seaweed, <italic>P. gymnospora</italic>). The concentration of cinnamic acid, sinapic acid, kaempferol, fisetin p-coumaric acid, ellagic acid, and luteolin in BW was 1.5–6-folds less than the PF. Inclusion of BW decreased (<italic>P</italic> &lt; 0.0001) CH<sub>4</sub> production by 34%, 38%, and 45% in A<sub>2</sub>, A<sub>5</sub>, and A<sub>10</sub> treatments, respectively. A decrease (<italic>P</italic> &lt; 0.0001) of 7.5%–8% in dry matter (DM) and organic matter (OM) digestibility was also recorded with the BW supplementation. The BW inclusion also decreased the numbers of total (<italic>P</italic> = 0.007), <italic>Entodinomorphs</italic> (<italic>P</italic> = 0.011), and <italic>Holotrichs</italic> (<italic>P</italic> = 0.004) protozoa. Metagenome data revealed the dominance of Bacteroidetes, Proteobacteria, Firmicutes, Actinobacteria, and Fibrobacter microbial phyla. At the phylum level, Euryarchaeota dominated the archaeal community, whereas <italic>Methanobrevibacter</italic> was most abundant at the genus level. It can be concluded that the inclusion of BW in straw and concentrate based diet by affecting rumen fermentation, protozoal numbers, and compositional shift in the archaeal community significantly decreased CH<sub>4</sub> production. Utilization of biowaste of <italic>P. gymnospora</italic> as a CH<sub>4</sub> mitigating agent will ensure its efficient utilization rather than dumping, which shall cause environmental pollution and health hazards.</p>