Fruits chemical composition and potential ruminal digestion of nine tree species in dry tropic region of Mexico

Chemical composition, in vitro gas production (GP), in vitro dry matter (DMD) and organic matter (OMD) digestibility, metabolizable energy (ME), gas yield (GY24h), short chain fatty acids (SCFA) and microbial mass production (MMP) were measured in fruits of nine trees species, using in vitro gas technique with and without polyethylene glycol (PEG:MW-4000) as chelating tannins agent. The fruits with the highest protein content (P < 0.001) (135.5–196.0 g/kg DM) were Leucaena esculenta, Pithecellobium acatlense, Acacia farnesiana and Enterolobium cyclocarpum, total phenols (P < 0.001) (349.8–553.1 g/kg DM) Lysiloma divaricata, A. farnesiana and Caesalpinia coriaria and condensed tannins (P < 0.001) L. divaricata and E. cyclocarpum with 95.7 and 71.7 g/kg DM, respectively. The highest DMD in fruits of C. coriaria, Pithecellobium dulce, A. farnesiana and L. esculenta (P < 0.001). The GP, OMD, ME, GY24h, SCFA and MMP, was different (P < 0.0001) between fruit trees. The PEG increased (P < 0.0001) the GP, ME, GY24h and SCFA in the fruits of Gliricidia sepium, L. esculenta and C. coriaria. In conclusion, the nutritional composition and in vitro fermentation parameters differs between fruits. The increase in PEG increased the value of GP, ME, OMD, GY24h and SCFA, indicating that the fruits contain phenolic compounds with biological activity that precipitate proteins.