Comparative study of some analytical methods to quantify lignin concentration in tropical grasses

• Published in: Animal bioscience Vol. 32; no. 11; pp. 1686 - 1694
• Main Authors: Velásquez, Alejandro V., Martins, Cristian M. M. R., Pacheco, Pedro, Fukushima, Romualdo S.
• Format: Journal Article
• Language: English
• Published: Korea (South) Asian - Australasian Association of Animal Production Societies 01.11.2019; Asian-Australasian Association of Animal Production Societies (AAAP) and Korean Society of Animal Science and Technology (KSAST); Asian-Australasian Association of Animal Production Societies; 아세아·태평양축산학회
• Subjects: acetyl bromide; acid detergent; Analysis; Bromine compounds; Comparative literature; degradability; Developmental biology; Grasses; Lignin; Methods; Plants (Organisms); Time; 축산학; Iran; Cameroon; Acetyl Bromide; Lignin; Acid Detergent; Degradability
• ISSN: 1011-2367; 2765-0189; 1976-5517; 2765-0235
• DOI: 10.5713/ajas.17.0450

Lignin plays a relevant role in the inhibition of cell wall (CW) structural carbohydrate degradation. Thus, obtaining accurate estimates of the lignin content in tropical plants is important in order to properly characterize the mechanism of lignin action on cell wall degradation. Comparing conflicting results between the different methods available for commercial use will bring insight on the subject. This way, providing data to better understand the relationship between lignin concentration and implications with tropical forage degradation. Five grass species, Brachiaria brizantha cv Marandú, Brachiaria brizantha cv Xaraés (MG-5), Panicum maximum cv Mombaça, Pennisetum purpureum cv Cameroon and Pennisetum purpureum cv Napier, were harvested at five maturity stages. Acid detergent lignin (ADL), Klason lignin (KL), acetyl bromide lignin (ABL) and permanganate lignin (PerL) were measured on all species. Lignin concentration was correlated with in vitro degradability. Highly significant effects for maturity, lignin method and their interaction on lignin content were observed. The ADL, KL and ABL methods had similar negative correlations with degradability. The PerL method failed to reliably estimate the degradability of tropical grasses, possibly due to interference of other substances potentially soluble in the KMnO4 solution. ADL and KL methods use strong acid (H2SO4) and require determination of ash and N content in the lignin residues, therefore, increasing time and cost of analysis. The ABL method has no need for such corrections and is a fast and a convenient method for determination of total lignin content in plants, thus, it may be a good option for routine laboratory analysis.