ENADE Zootecnia Practice Questions - ENADE Zootecnia - Exame Nacional De Desempenho Dos Estudantes Exam

Cellulolytic bacteria such as Fibrobacter succinogenes and Ruminococcus albus require a ruminal pH above 6.0 to 6.2 and produce primarily acetate, whereas amylolytic bacteria like Streptococcus bovis tolerate lower pH levels and rapidly produce lactate and propionate. Cellulolytic bacteria such as Butyrivibrio fibrisolvens require an acidic ruminal pH below 5.5 to synthesize active cellulase multi-enzyme complexes, whereas amylolytic species like Selenomonas ruminantium become completely dormant when ruminal pH drops below 6.5 in feedlot cattle. Amylolytic bacteria such as Streptococcus bovis degrade structural cellulose and hemicellulose exclusively when ruminal pH exceeds 6.8, whereas cellulolytic species like Ruminococcus flavefaciens ferment non-structural plant pectins into high concentrations of lactic acid in the rumen. Cellulolytic bacteria utilize non-protein nitrogen to generate high proportions of propionate and branched-chain volatile fatty acids, while amylolytic species degrade lignified vascular plant bundles via extracellular cellulosome complexes under acidic conditions in the rumen.