Tropical tree foliage supplementation in ruminants improves rumen fermentation and the bacterial profile and decreases methane production.

The main of this study was to evaluate the effect of supplementation of tropical tree foliage in ruminant diets on the in vitro fermentation, bacterial population, volatile fatty acids (VFAs), and enteric CH4 production. Seven experimental diets were evaluated: a control treatment of Pennisetum purpureum (T7) and six treatments of P. purpureum supplemented (30%) with the foliage of Neomillspaughia emargiata (T1), Tabernaemontana amygdalifolia (T2), Caesalpinia gaumeri (T3), Piscidia piscipula (T4), Leucaena leucocephala (T5), and Havardia albicans (T6). The T2, T7, and T5 treatments had the highest (p < 0.05) digestibility of dry matter. Overall, supplementation increased (p < 0.05) the concentrations of propionic and butyric acid and decreased acetic acid. Methanogenic bacteria decreased (p < 0.05) in T1, T2, T5, and T6. Ruminococcus albus decreased in T1, T2, T3, and T5 and Selenomonas ruminiantum increased in T3. Fibrobacter succinogenes increased, except in T5. Methane production decreased (p < 0.05) in T1, T4, T5, and T6. The supplementation with Leucaena leucocephala, Tabernaemontana amygdalifolia, Neomillspaughia emargiata, Piscidia piscipula, Havardia albicans, and Caesalpinia gaumeri is a potential alternative nutritional strategy for ruminants that results in positive changes in VFAs profile, a decrease on CH4 production and methanogenic bacteria, and changes on fibrolytic and non-fibrolytic bacteria composition.HIGHLIGHTSTropical tree foliage supplementation increased propionic and butyric acid and decreased acetic acid concentrations.Fibrolytic, non-fibrolytic, and Methanogenic bacteria were selectively modulated with the supplementation of tropical tree foliage.The enteric methane (CH4) production decreased with the supplementation of tree foliage.The supplementation of Tabernaemontana amygdalifolia and Leucaena leucocephala had the highest digestibility and is a potential alternative nutritional strategy for ruminants.

Energy utilization, nitrogen balance and microbial protein supply in cattle fed Pennisetum purpureum and condensed tannins.

The aim of the experiment was to assess the effect of condensed tannins (CT) on feed intake, dry matter digestibility, nitrogen balance, supply of microbial protein to the small intestine and energy utilization in cattle fed a basal ration of Pennisetum purpureum grass. Five heifers (Bos taurus × Bos indicus) with an average live weight of 295 ± 19 kg were allotted to five treatments consisting of increasing levels of CT (0, 1, 2, 3 and 4% CT/kg DM) in a 5 × 5 Latin square design. Dry matter intake (DMI) was similar (p > 0.05) between treatments containing 0, 1, 2 and 3% of CT/kg DM and it was reduced (p < 0.05) to 4% CT (5.71 kg DM/day) with respect to that observed with 0% CT (6.65 kg DM/day). Nitrogen balance, purine derivatives excretion in urine, microbial protein synthesis and efficiency of synthesis of microbial nitrogen in the rumen were not affected (p ≥ 0.05) by the increase in the levels of condensed tannins in the ration. Energy loss as CH4 was on average 2.7% of the gross energy consumed daily. Metabolizable energy intake was 49.06 MJ/day in cattle fed low-quality tropical grass with a DMI of 6.27 kg/day. It is concluded that concentrations of CT between 2 and 3% of DM of ration reduced energy loss as CH4 by 31.3% and 47.6%, respectively, without affecting intakes of dry and organic matter; however, digestibilities of dry and organic matter are negatively affected.