Nutritional profile and leaf surface structure of some monocotyledonous and dicotyledonous species for grazing ruminants in semiarid regions of northeastern mexico

Abstract

This study describes some aspects of nutritional and leaf ultrastructural characteristics of 8 monocotyledonous and 7 dicotyledonous species, showing large variations in these characters. High crude protein (CP) content was observed for monocotyledonous species such as Cyanodon dactylon (11%) and Bouteloua trifida (10.5%) as well as for dicotyledons Ruelia corzoi (19%) Lantaha macropoda (19%), Palafoxia texana (18.6%) and Sida filicaulis (18%). In general, dicotyledonous species showed greater in situ digestibility of dry matter (ISDDM), crude protein (ISDCP) and neutral detergent fiber (ISDNDF). Linear regression equations between in situ digestibilities and nutrient content showed that digestibility of all plant species was negatively influenced by their fiber content and positively by their CP content. Both mono and dicotyledonous speciesshowed large variations in the presence, abondance and size of trichomes, crystals and type of epicuticular wax. Low trichome number, less pubescence, silica contents and smooth epicuticular wax and high CP, low NDF and high in situ digestibility of DM and CP are desirable characteristics for grazing animals preference. The presence of smooth epicuticular wax and trichomes are characters related to drought resistance of some of the species prevalent in semiarid Mexico. Therefore, ultrastructural characteristics of leaf surface might be related to the preference or non preference by the grazing animals. © GSP, India.