Tannic acid resistance in ruminal streptococcal isolates

Area of Science:

• Microbiology
• Ruminant Nutrition
• Biochemistry

Background:

• Tannins in cattle feed can reduce nutrient availability and animal performance.
• Identifying microorganisms capable of degrading tannins is crucial for improving ruminant digestion.
• Streptococcus species are common inhabitants of the rumen environment.

Purpose of the Study:

• To investigate the tannin tolerance and degradation capabilities of Streptococcus isolates from non-adaptive cattle rumen.
• To assess the impact of tannic acid concentration on the growth and morphology of these isolates.
• To confirm the presence of tannase activity in the selected Streptococcus strains.

Main Methods:

• Isolation and cultivation of Streptococcus spp. from cattle rumen samples.
• Growth experiments in BHI broth with varying concentrations of tannic acid (0-50 g/l).
• Monitoring of lag phase duration and microscopic observation of cell morphology.
• Qualitative assessment of tannase enzyme activity.

Main Results:

• Streptococcus isolates demonstrated tolerance to tannic acid up to 50 g/l.
• Increased tannic acid concentration prolonged the lag phase from 1.5 to 6 hours.
• Cell morphology shifted from diplococci to elongated chains (40-50 cells) with increasing tannic acid (1-4%).
• Tannase activity was qualitatively confirmed in the isolates.

Conclusions:

• Rumen Streptococcus isolates possess significant tannic acid tolerance and degradation potential.
• Tannic acid exposure induces adaptive changes in Streptococcus growth kinetics and cell morphology.
• These findings highlight the potential of these Streptococcus strains for mitigating anti-nutritional effects of tannins in ruminant diets.