Effect of tannins from tropical plants on methane production from ruminants: A systematic review.

Methane (CH4) is a greenhouse gas generated during the feed fermentation processes in the rumen. However, numerous studies have been conducted to determine the capacity of plant secondary metabolites to enhance ruminal fermentation and decrease CH4 production, especially those plants rich in tannins. This review conducted a descriptive analysis and meta-analysis of the use of tannin-rich plants in tropical regions to mitigate CH4 production from livestock. The aim of this study was to analyse the effect of tannins supplementation in tropical plants on CH4 production in ruminants using a meta-analytic approach and the effect on microbial population. Sources of heterogeneity were explored using a meta-regression analysis. Final database was integrated by a total of 14 trials. The 'meta' package in R statistical software was used to conduct the meta-analyses. The covariates defined a priori in the current meta-regression were inclusion level, species (sheep, beef cattle, dairy cattle, and cross-bred heifers) and plant. Results showed that supplementation with tropical plants with tannin contents have the greatest effects on CH4 mitigation . A negative relationship was observed between the level of inclusion and CH4 emission (-0.09), which means that the effect of CH4 mitigation is increasing as the level of tannin inclusion is higher. Therefore, less CH4 production will be obtained when supplementing tropical plants in the diet with a high dose of tannins.

Kinetic and in vitro ruminal fermentation characteristics of copra meal diets with different fat levels

This study aimed at evaluating the chemical composition and in vitro ruminal characteristics of diets using copra meal with different fat contents. Three levels of copra meal inclusion (10, 20 and 30%) and two levels of fat (high-fat copra meal HFCM and low-fat copra meal LFCM) were used in replacement of soybean meal. The addition of copra meal increased EE and reduced CP and NFC of diets, especially when HFCM was included. Treatments with the inclusion of 30% copra meal had a higher colonization time (L), independently of fat content. The maximum gas production was reduced from 59.06 to 39.21 mL/g DM with the addition of HFCM, but was not affected when diets contained LFCM. Digestibility was also reduced with the addition of copra meal, the highest reduction being with the addition of 30% copra meal. Copra meal inclusion has reduced the ammonia concentration from 29.75 mg/100 mL (control diet) to 17.05 mg/100 mL (30% copra meal) but did not affect significantly methane production. Copra meal impacts the chemical composition and ruminal fermentation characteristics of diets, especially when containing high oil content.

Kinetic and in vitro ruminal fermentation characteristics of copra meal diets with different fat levels

This study aimed at evaluating the chemical composition and in vitro ruminal characteristics of diets using copra meal with different fat contents. Three levels of copra meal inclusion (10, 20 and 30%) and two levels of fat (high-fat copra meal HFCM and low-fat copra meal LFCM) were used in replacement of soybean meal. The addition of copra meal increased EE and reduced CP and NFC of diets, especially when HFCM was included. Treatments with the inclusion of 30% copra meal had a higher colonization time (L), independently of fat content. The maximum gas production was reduced from 59.06 to 39.21 mL/g DM with the addition of HFCM, but was not affected when diets contained LFCM. Digestibility was also reduced with the addition of copra meal, the highest reduction being with the addition of 30% copra meal. Copra meal inclusion has reduced the ammonia concentration from 29.75 mg/100 mL (control diet) to 17.05 mg/100 mL (30% copra meal) but did not affect significantly methane production. Copra meal impacts the chemical composition and ruminal fermentation characteristics of diets, especially when containing high oil content.(AU)