Sequential Extraction of Proanthocyanidin Fractions from Ficus Species and Their Effects on Rumen Enzyme Activities In Vitro

Abstract

Three proanthocyanidin fractions per species were sequentially extracted by 50% (v/v) methanol–water, 70% (v/v) acetone–water, and distilled water from leaves of Ficus racemosa (fractions FR) and F. religiosa (fractions FRL) to yield fractions FR-50, FR-70, FR-DW, FRL-50, FRL-70, and FRL-DW. Fractions were examined for their molecular structure, effect on ruminal enzyme activities, and principal leaf protein (Rubisco) solubilization in vitro. All fractions except FRL-70 contained flavonoids including (+) catechin, (−) epicatechin, (+) gallocatechin, (−) epigallocatechin, and their -4-phloroglucinol adducts. The fractions FRL-50 and FRL-DW significantly (p < 0.05) inhibited the activity of ruminal glutamic oxaloacetic transaminase and glutamic pyruvic transaminase. All fractions inhibited glutamate dehydrogenase activity (p < 0.05) with increasing concentration, while protease activity decreased 15–18% with increasing concentrations. Fractions FRL-50 and FRL-DW completely inhibited the activity of cellulase enzymes. Solubilization of Rubisco was higher in F. religiosa (22.36 ± 1.24%) and F. racemosa (17.26 ± 0.61%) than that of wheat straw (WS) (8.95 ± 0.95%) and berseem hay (BH) (3.04 ± 0.08%). A significant (p < 0.05) increase in protein solubilization was observed when WS and BH were supplemented with FR and FRL leaves at different proportions. The efficiency of microbial protein was significantly (p < 0.05) greater in diets consisting of WS and BH with supplementation of F. racemosa leaves in comparison to those supplemented with F. religiosa leaves. The overall conclusion is that the fractions extracted from F. religiosa showed greater inhibitory effects on rumen enzymes and recorded higher protein solubilization in comparison to the F. racemosa. Thus, PAs from F. religiosa are potential candidates to manipulate rumen enzymes activities for efficient utilization of protein and fiber in ruminants.

The study of structure and effects of two new proanthocyanidins from Anogeissus pendula leaves on rumen enzyme activities

“…This inhibition effect of phenolic compounds could be a result of their antimicrobial nature and the release of other metabolites during the fermentation process. Similar observations were recorded in cow rumen kinetics ( 14 ) from phenolic extracts of Ficus species ( 17 ) and methanolic tree leaves extracts of A. pendula ( 25 ). The released or break-down products of phenolic compounds from the plant extracts can be turned into new antioxidants ( 45 ) and that could reduce ruminal enzymatic activities.…”

“…The trend for reduction in the concentration of liberated rumen protein by the addition of compounds 1 and 2 with increasing concentrations and incubation times was also observed by others with condensed tannins extracted from Lotus pedunculatus ( 48 ), proanthocyanidins obtained from Ficus species ( 17 ), and tannin-rich forage leaves ( 49 , 50 ). This could be due to the steric interference at interaction sites of protease and receptors.…”

“…A ruminal cellulase extract was prepared from collected rumen liquor, and the effect of isolated compounds on its activities was estimated according to a described method ( 23 ). A protocol for determining the activity of the intracellular enzymes glutamic pyruvic transaminase (GPT) and glutamic oxaloacetic transaminase (GOT) was used ( 24 ) while obtaining from the bacterial and protozoal fractions of the rumen liquor and then separation of bacteria and protozoal rich enzyme extracts in 0.1 M phosphate buffer of pH 6.8 were carried out according to our published methods ( 17 , 22 , 25 ). To measure proteolytic enzyme activities, the concentration of protein in enzyme extracts was estimated according to Lowry ( 26 ).…”

“…In our previous studies, we assessed leaves of A. pendula for contents of crude protein (9.8–10.6%), neutral detergent fiber (46.4–58.6%), lignin (13.5–15.3%), and in vitro dry matter digestibility (25–38%) ( 13 ). Here, our research aimed to understand the phytochemical/structural properties of A. pendula phenolics (flavonoids or PAs) in relation to their effects on rumen enzyme activities ( 14 – 17 ). The use of natural compounds in animal feed has become an increasingly popular area of research, with the goal of improving animal health and productivity while minimizing negative environmental impacts.…”

Antioxidants in Animal Nutrition: UHPLC-ESI-QqTOF Analysis and Effects on In Vitro Rumen Fermentation of Oak Leaf Extracts

“…Therefore, a reduction of protein degradation in the rumen is associated with a lower production of ammonia and a greater flow of non-ammoniacal nitrogen to the duodenum and a higher amount of branched fatty acids. In this context, it has been observed that the proanthocyanidin fractions from the leaves of some species of Ficus or Anogeissus pendula and Eugenia jambolana , mainly composed of (epi)catechin, (epi)gallocatechin and their 4-phloroglucinol adducts, decrease the glutamic oxaloacetic ruminal and pyruvic transaminases as well as rumen R-Cellulase enzymes with consequent effects on the use of fibers and proteins [ 82 , 83 ]. Dietary condensed or hydrolysable tannins, supplied at adequate concentrations, are agreed to reduce in vitro concentrations of rumen NH 3 and branched-chain volatile fatty acids.…”