Characterization of Condensed Tannins from Purple Prairie Clover (Dalea purpurea Vent.) Conserved as either Freeze-Dried Forage, Sun-Cured Hay or Silage

Effects of Lactobacillus plantarum on Fermentation Quality and Anti-Nutritional Factors of Paper Mulberry Silage

There are few studies on the application of lactic acid bacteria in the reduction of anti-nutrient factors in paper mulberry silage. This study aimed to investigate the effects of different lactic acid bacteria on the fermentation quality and the amount of anti-nutritional factors in paper mulberry silage. Two strains of Lactobacillus plantarum (GX, isolated from paper mulberry silage; GZ, provided by Sichuan Gaofuji Biotechnology Co. Ltd.) were added as silage additives. On days 7, 15, 30 and 60 of the ensiling process, the fermentation quality, and the amount of anti-nutritional factors were measured. Compared with the control group, inoculation with Lactobacillus plantarum could rapidly reduce pH values, leading to lower NH3-N/TN. Besides, it also significantly increased the lactic acid content (p < 0.05). The two strains of L. plantarum significantly reduced the content of hydrolysed tannin, condensed tannin, total tannin, oxalic acid, phytic acid and saponin (p < 0.05). Overall, this study found that the addition of lactic acid bacteria could significantly improve the fermentation quality of paper mulberry and reduce the amount of anti-nutrient factors (p < 0.05).

Composition and Protein Precipitation Capacity of Condensed Tannins in Purple Prairie Clover (Dalea purpurea Vent.)

This study aimed to determine the concentration and composition of condensed tannins (CT) in different tissues of purple prairie clover (PPC; Dalea purpurea Vent.) at different maturities and to determine their protein-precipitating capacity. The compositions of CT were elucidated after thiolysis with benzyl mercaptan followed by high-performance liquid-chromatography (HPLC) and ¹H-¹³C heteronuclear single quantum coherence (HSQC) NMR spectroscopy. The results indicated that PPC flowering heads contained the highest CT concentration. Purple prairie clover CT consisted mainly of epicatechin (EC) and epigallocatechin (EGC) subunits. CT in the leaves were composed of more EC and less EGC than CT in stems and flowering heads at both the early flowering (EF) and late flowering (LF) head stages. The mean degree of polymerization was the highest for CT in stems and increased with maturity. CT isolated from PPC leaves at the early flowering head stage exhibited the greatest biological activity in terms of protein precipitation. Overall, the CT in PPC were predominantly procyanidins and the concentration and composition varied among the plant tissues and with maturity.

Impact of condensed tannin-containing legumes on ruminal fermentation, nutrition, and performance in ruminants: a review

Legume forages, such as sainfoin (Onobrychis viciifolia Scop.) and birdsfoot trefoil (Lotus corniculatus L.), can increase the forage quality and quantity of Western Canadian pastures, thus increasing producer profitability due to increased gains in grazing ruminants, while also reducing risk of bloat in legume pastures due to the presence of proanthocyanidins. Proanthocyanidins or condensed tannins (CT) are secondary plant polyphenol compounds that have been regarded as anti-nutritional due to their ability to bind protein in feeds, enzymes, and microbial cells, therefore disrupting microbial digestion and slowing ruminal protein and dry matter (DM) digestion. Research has shown that at high concentrations (>50 g·kg−1 DM), CT can disrupt microbial digestion. However, at low dietary inclusion rates (5–10 g·kg−1 DM), they reduce bloat risk, increase ruminal undegradable protein, reduce enteric methane production, and benefit anthelmintic activity. Yet, research gaps still exist regarding grazing persistence and forage yield of novel CT-containing forages and their biological activity due to their vast differences in CT stereochemistry, polymer size, and intermolecular linkages. The objectives of this review are to summarize information regarding the impact of CT on ruminal fermentation, carbohydrate and protein metabolism, and the potential to identify and select for forages that contain CT for ruminant production.

Pollution by Antibiotics and Antimicrobial Resistance in LiveStock and Poultry Manure in China, and Countermeasures

The demand for animal protein has increased considerably worldwide, especially in China, where large numbers of livestock and poultry are produced. Antibiotics have been widely applied to promote growth and prevent diseases. However, the overuse of antibiotics in animal feed has caused serious environmental and health risks, especially the wide spread of antimicrobial resistance (AMR), which seriously affects animal and human health, food safety, ecosystems, and the sustainable future development of animal protein production. Unfortunately, AMR has already become a worldwide challenge, so international cooperation is becoming more important for combatting it. China’s efforts and determination to restrict antibiotic usage through law enforcement and effective management are of significance. In this review, we address the pollution problems of antibiotics; in particular, the AMR in water, soil, and plants caused by livestock and poultry manure in China. The negative impact of widespread and intensive use of antibiotics in livestock production is discussed. To reduce and mitigate AMR problems, we emphasize in this review the development of antibiotic substitutes for the era of antibiotic prohibition.

Examining the Variables Leading to Apparent Incongruity between Antimethanogenic Potential of Tannins and Their Observed Effects in Ruminants—A Review

In recent years, several secondary plant metabolites have been identified that possess antimethanogenic properties. Tannin-rich forages have the potential to reduce methane emissions in ruminants while also increasing their nutrient use efficiency and promoting overall animal health. However, results have been highly inconclusive to date, with their antimethanogenic potential and effects on both animal performance and nutrition being highly variable even within a plant species. This variability is attributed to the structural characteristics of the tannins, many of which have been linked to an increased antimethanogenic potential. However, these characteristics are seldom considered in ruminant nutrition studies—often because the analytical techniques are inadequate to identify tannin structure and the focus is mostly on total tannin concentrations. Hence, in this article, we (i) review previous research that illustrate the variability of the antimethanogenic potential of forages; (ii) identify the source of inconsistencies behind these results; and (iii) discuss how these could be optimized to generate comparable and repeatable results. By adhering to this roadmap, we propose that there are clear links between plant metabolome and physiology and their antimethanogenic potential that can be established with the ultimate goal of improving the sustainable intensification of livestock.

Conserving purple prairie clover (Dalea purpurea Vent.) as hay and silage had little effect on the efficacy of condensed tannins in modulating ruminal fermentation in vitro

BACKGROUND

The objective of this study was to determine the effects of forage conservation method and condensed tannins (CT) in conserved forage on rumen fermentation. Purple prairie clover (PPC; Dalea purpurea Vent.) containing 84.5 g kg^-1 dry matter (DM) of CT was harvested at full flower and preserved as freeze-dried green chop (F), hay (H) or silage (S). Batch culture incubations were conducted using conserved forages as a substrate and treatments were arranged as 3 × 2 factorial design of forage type (F, H and S) with or without polyethylene glycol (PEG). PEG was used to isolate the effects of CT on fermentation. Incubation was repeated twice with quadruplicate vials for each treatment in each incubation. ¹⁵ N-labelled ammonium sulfate was used as microbial N marker and headspace gas was sampled to determine methane production.

RESULTS

Concentrations of neutral detergent fiber (NDF) and acid detergent fiber were lower (P < 0.01) in F than in H or S. Ensiling decreased (P < 0.001) total phenolics and extractable CT, but had no effect on total CT, whereas none of these phenolic fractions were altered in H. Hay and silage had lower (P < 0.01) true DM disappearance (TDMD) and NDF disappearance (NDFD) than F. Inclusion of PEG did not affect TDMD or NDFD after 8, 24 or 72 h of incubation. Productions of total gas, methane and total volatile fatty acid and the rate of gas production (c) were also similar, but ammonia was higher (P < 0.05) and microbial N was lower (P < 0.05) with than without PEG after 72 h of incubation. After 72 h, a lower (P < 0.001) proportion of acetate but higher (P < 0.05) proportion of propionate was noted with S, resulting in a lower (P < 0.001) acetate:propionate ratio as compared to F or H after 8 h of incubation.

CONCLUSION

Condensed tannins in PPC decreased protein degradation in vitro, but had minimal effects on overall rumen fermentation, and conservation of PPC as hay or silage had little effect on the efficacy of CT in modulating rumen fermentation. © 2020 Her Majesty the Queen in Right of Canada. Journal of The Science of Food and Agriculture © 2020 Society of Chemical Industry.

Inhibitory effects and molecular mechanism on mushroom tyrosinase by condensed tannins isolation from the fruit of Ziziphus jujuba Mill. var. spinosa (Bunge) Hu ex H. F. Chow

The structure of extracted condensed tannin (CT) from the fruit of Sour jujube (Ziziphus jujuba Mill. var. spinosa (Bunge) Hu ex H. F. Chow) and the molecular mechanisms by which CT inhibits the activity of mushroom tyrosinase were investigated. The structure of CT was characterized by high performance liquid chromatography electrospray ionization mass spectrometry, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The kinetic assays were used to detect inhibition effect, type and mechanism. UV scanning, fluorescence quenching, copper interacting, o-quinone interaction and molecular docking assays were also used to reveal the molecular mechanisms by which CT inhibit tyrosinase. The results showed the structural units of CT containing afzelechin/epiafzelechin, catechin/epicatechin, and gallocatechin/epigallocatechin. Kinetic analysis showed that CT inhibits both the monophenolase and diphenolase activities of tyrosinase and exhibits reversible, mixed type mechanism. The fruit CT interacts primarily with the copper ions and specific amino acid residue (Asn191, Thr203, Ala202, Ser206, Met201, His194, His54, Glu182 and Ile42) in the active site of tyrosinase to disturb oxidation of substrates by tyrosinase. These results suggested the sour jujube fruit is a potential natural source of tyrosinase inhibitors, and has a potential to be used in food preservation, whitening cosmetics.

The Effect of Ensiling on the Nutritional Composition and Fermentation Characteristics of Brown Seaweeds as a Ruminant Feed Ingredient

Simple Summary

In recent years, there has emerged a renewed interest in the inclusion of seaweed as an animal feed ingredient. Due to annual fluctuations in the availability and biochemical composition of seaweeds, effective preservation methods are needed. These are currently restricted to thermal processing methods. Ensiling is a commonly applied preservation technique for terrestrial forages intended for livestock feed but little is known about the characteristics of silage made from seaweeds. This study considered the potential of ensiling two brown seaweed species (Fucus vesiculosus and Saccharina latissimi) with or without the use of a microbial inoculant. The potential applications of seaweed silage as a feed ingredient in ruminant diets were considered. The results showed that, depending on the species, ensiling may be a suitable preservation method for brown seaweeds.

Abstract

Ensiling could be an effective method to preserve seaweeds for animal feed applications, however, there is limited scientific knowledge in this area. Seaweeds are a promising ruminant feed ingredient, in part due to the content of phenolic compounds, which are receiving considerable interest as alternative antimicrobial agents in feed. The aim of the study was to compare the effect of ensiling on the nutritional composition and fermentation characteristics of two brown seaweed species, Fucus vesiculosus (FV) and Saccharina latissimi (SL) with or without the use of a Lactobacillus plantarum (LAB) inoculant. The effect of ensiling on the stability of phlorotannin was also investigated using nuclear magnetic resonance (NMR). After harvesting, the seaweeds were wilted for 24 h and subsequently ensiled in laboratory-scaled silos for 90 days. SL silage showed a stronger fermentation pattern (pH < 4), dominated by lactic acid (50–60 g/kg Dry Matter (DM)), and a slightly higher acetic acid content compared to FV silages (p < 0.05). The fermentability of FV was limited (pH > 4.8) with low lactic acid production (<5 g/kg DM). The addition of the LAB inoculant showed no effect on the fermentation process but a modest effect on the chemical composition of both species was observed after the 90-day ensiling period. The results showed no losses in the nutrient content of FV after ensiling, however losses in the Crude Protein (CP, −32%), ash (−36%), Neutral Detergent Fibre (NDF, −77%) and Acid Detergent Fibre (ADF, −58%) content of SL were observed. The ensiling process had a limited effect on the in vitro true dry matter digestibility and phenolic content of either species. Therefore, ensilage may be a suitable preservation method for the use of brown seaweeds as a ruminant feed; however, species-specific differences were observed.

Direct versus Sequential Analysis of Procyanidin- and Prodelphinidin-Based Condensed Tannins by the HCl-Butanol-Acetone-Iron Assay

In this study, we optimized the HCl-butanol-acetone-iron (HBAI) assay for the analysis of B-linked procyanidin (PC) and prodelphinidin (PD) condensed tannins (CTs) by direct analysis of whole tissue and sequential analysis of acetone-water extracts and insoluble residues prepared from forage, woody plant, food, and food byproduct samples. Yields of anthocyanidins (cyanidin and delphinidin) were optimized by heating ≤0.25 mg mL^-1 CT standards, 1 mg mL^-1 tissue, or 1-2 mg mL^-1 acetone-water fractioned tissue for 3 h at 70 °C in medium containing 5% concentrated HCl, 6.7% total water, 50% acetone, 42% n-butanol, and 0.15% ammonium iron(III) sulfate dodecahydrate. Accurate quantitation required CT standards of known purity sourced from the same tissue being analyzed. Both analysis methods provided comparable estimates of total CTs for most PD-rich samples, but only the sequential method gave good recovery and accurate estimates of CTs in most PC-rich samples.