Effects of leaf and stem maturation on nutritional value in Megathyrsus maximus

HERNÁNDEZ ÁLVAREZ, URYS M.; LÓPEZ COLOMBA, ELIANA; BOLLATI, GRACIELA P.; CARLONI, EDGARDO J.; REUTEMANN, ANDREA G.; GRUNBERG, KARINA A.

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE

JOHN WILEY & SONS LTD

Año: 2024

0022-5142

Background:Megathyrsus maximusis a forage grass native to Africa but widely cultivated in tropical and subtropical regions ofthe world where it is part of the grazing food chain. This study aimed to evaluatefiveM. maximusgenotypes for the effect ofmaturity on their morpho-agronomic traits, nutritional composition and digestibility, and to correlate their leaf blade and stemanatomy with their nutritional value.Results: The proportion of sclerenchyma tissues increased as maturity was reached, while lignin accumulation was differenti-ated between genotypes. Gatton Panic, Green Panic and Mutale genotypes maintained their acid detergent lignin (ADL) valuesfor leaf blades in the three cuts evaluated.In saccoruminal dry matter disappearance was lower in Green Panic genotype at thevegetative stage for stems, but not for leaf blades. Significant positive correlations were found between dry matter disappear-ance and mesophyll tissues, and the latter were negatively correlated with neutral detergentfiber (NDF) and ADL.Conclusion: Our results strongly indicate that cutting age and genotype affected the nutritional value ofM. maximusleaf bladesand stems, with a more pronounced loss of quality in stems than in leaf blades. We recommend increasing the frequency ofgrazing at early stage or anticipating the stage of stem elongation in Green Panic to produce forage with better nutritionalvalue