Studies aiming to validate the acetyl bromide lignin method for quantification of lignin content in tropical forages

• Grant number: 13/07430-0
• Support Opportunities: Regular Research Grants
• Start date: December 01, 2013
• End date: November 30, 2015
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Romualdo Shigueo Fukushima
• Grantee: Romualdo Shigueo Fukushima
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

It is well known that there is not an ideal method for lignin quantification in plant products. However, the spectroscopic acetyl bromide lignin (ABL) method for quantifying lignin content in plants has been gathering considerable attention from researchers worldwide (five of our articles were cited 304 times, over 90% from foreign authors - source: scholar.google.com.br). In this method, plant lignin is solubilized into a 25% acetyl bromide/acetic acid solution and the optical density (absorbance) measured with ultraviolet light at 280 nm wavelength. The absorbance reading is plugged in a regression equation that we developed, and lignin concentration is obtained (g/kg DM). Aiming this method to be better accepted by the scientific community, it must obviously be convincing and attractive. The present research project intends to gather information by focusing analyses on several forage species, various maturity stages, different plant tissues (stalk and leaf), and several harvest locations (this project may take as long as 2 years for its completion). It will require at least one biological testing as reference, for example, in vitro dry matter digestibility; and because lignin is closely associated to the fibrous structure of the cell wall, also an in vitro neutral detergent fiber (NDF) assay is highly recommended. Accuracy of analytical procedures employed nowadays are questionable, particularly the acid detergent lignin (ADL), which is one of the most widely used method nowadays. Usually grasses and legumes show different slopes between ADL and dry matter digestibility, steeper curve for grasses. This observation prompted several authors to the hypothesis that grass lignin is more inhibitory to digestion than is legume lignin. However, recent data (submitted to publication) revealed that for ABL, digestibility of grasses and legumes had exactly the same slopes, that is, grass lignin is no more inhibitory to digestion than is legume lignin. It is very important to ascertain if this observation is repeatable, and if so, proceed to an in-depth investigation to this matter of similar inhibitory effect of lignin upon structural carbohydrates of grasses and legumes. It is hoped that an advantageous technique (in terms of accuracy and precision in measuring lignin content, cost and time spent in the analyses) be offered, relative to other analytical procedures. Obviously other methods used to quantify lignin will be run for comparative purposes. Results from all methods will be correlated with plant digestibility data. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

VELASQUEZ, ALEJANDRO V.; MARTINS, CRISTIAN M. M. R.; PACHECO, PEDRO; FUKUSHIMA, ROMUALDO S.. Comparative study of some analytical methods to quantify lignin concentration in tropical grasses. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES, v. 32, n. 11, p. 1686-1694, NOV 2019. (13/07430-0)

VELASQUEZ, A. V.; DA SILVA, G. G.; SOUSA, D. O.; OLIVEIRA, C. A.; MARTINS, C. M. M. R.; DOS SANTOS, P. P. M.; BALIEIRO, J. C. C.; RENNO, F. P.; FUKUSHIMA, R. S.. Evaluating internal and external markers versus fecal sampling procedure interactions when estimating intake in dairy cows consuming a corn silage-based diet. JOURNAL OF DAIRY SCIENCE, v. 101, n. 7, p. 5890-5901, JUL 2018. (13/07430-0)