CELL-WALL COMPOSITION AND DIGESTIBILITY OF FIVE NATIVE SHRUBS OF THE TAMAULIPAN THORNSCRUB IN NORTHEASTERN MEXICO

Abstract

Background: Many trees and shrubs from different parts of the world have forage potential, because they are inexpensive local products used for small ruminants as feed resource, some of these native shrubs are currently already an important fodder resources in arid and semi-arid regions of Northeastern México. Objective: The aim of this study was to determine the cell-wall composition and in vitro leaf digestibility of five shrub species: Celtis pallida, Croton suaveolens, Forestiera angustifolia, Guaiacum angustifolium and Parkinsonia aculeata. Methodology: Plant material was collected monthly from July 2018 to June 2019 at two sampling sites in Nuevo León, México: Linares and Los Ramones Counties. In vitro dry matter digestibility (IVDMD) was calculated using the DaisyII incubator. Results: Non-structural carbohydrates (NSC) (total mean = 22.4% dry matter) varied significantly among species, sites, and months (p<0.001, p<0.05 and p<0.001, respectively). Conversely, neither acid detergent lignin (ADL) (8.4%), crude protein (CP) (21.9%), cellulose (12.5%), hemicellulose (20.8%), nor IVDMD (75.5%) varied significantly between sites. In general, NSC values were higher in Linares. The highest and lowest IVDMD values as per the DaisyII incubator were recorded in March and September, respectively. C. pallida showed the highest IVDMD associated with a high hemicellulose and low ADL values, whereas P. aculeata showed a lower IVDMD value and high cellulose content. Implications: All species maintained considerably high levels of digestibility, which might indicate an availability of high CP levels for consumption by ruminants in the semi-arid regions of northeastern México. Conclusion: It is concluded that the species under study can be considered as emergency feed resources for small ruminants throughout the year.