Effect of tannin degradation of mangrove (Sonneratia alba) fruit on nutrient digestibility, protozoa population and methane gas production

This study examined the fermentation duration in relation to the effectiveness of tannin levels in mangrove (Sonneratia alba) fruit during the fermentation process using Aspergillus niger. The tested durations were 7, 10, 13, and 16 days in anaerobic conditions. The outcomes measured included crude fat, crude fibre, and nitrogen-free extract digestibility. Microbial biomass, protozoa population, and methane gas production were also recorded as responses to the rumen microbial activity. The results showed that 16 days of fermentation gave the highest average for all responses. The protozoa population reached around 4.07 × 105 cells/ml and methane gas amounted to 33.9 ml/g of dry matter (DM). This is caused by a decrease in the anti-nutrient tannin content in mangrove (S. alba) fruit due to fermentation by A. niger according to treatment. The conclusion of this research is that the 16-day fermentation treatment (T4) of mangrove fruit is the optimal time to be used as a source of concentrate feed for livestock in terms of the increase in nutritional value and gastrointestinal microbes represented by total protozoa population, crude fibre digestibility, crude fat digestibility, and the highest nitrogen-free extract digestibility. However, microbial biomass and methane gas production were not significantly different in this study.