Condensed tannins (CTs) account for up to 20% of the dry matter in forage legumes used as ruminant feeds. Beneficial animal responses to CTs have included improved growth, milk and wool production, ...fertility, and reduced methane emissions and ammonia volatilization from dung or urine. Most important is the ability of such forages to combat the effects of gastrointestinal parasitic nematodes. Inconsistent animal responses to CTs were initially attributed to concentration in the diet, but recent research has highlighted the importance of their molecular structures, as well as concentration, and also the composition of the diet containing the CTs. The importance of CT structural traits cannot be underestimated. Interdisciplinary research is the key to unraveling the relationships between CT traits and bioactivities and will enable future on‐farm exploitation of these natural plant compounds. Research is also needed to provide plant breeders with guidelines and screening tools to optimize CT traits, in both the forage and the whole diet. In addition, improvements are needed in the competitiveness and agronomic traits of CT‐containing legumes and our understanding of options for their inclusion in ruminant diets. Farmers need varieties that are competitive in mixed swards and have predictable bioactivities. This review covers recent results from multidisciplinary research on sainfoin (Onobrychis Mill. spp.) and provides an overview of current developments with several other tanniniferous forages. Tannin chemistry is now being linked with agronomy, plant breeding, animal nutrition, and parasitology. The past decade has yielded considerable progress but also generated more questions—an enviable consequence of new knowledge!
This study investigated the separate and combined anthelmintic (AH) effects of different phenolic compounds, including condensed tannins and flavonoids, all of which are known to occur in willow ...leaves, a potentially valuable dry season feed. A range of contrasting model tannins, which span the whole range of willow tannins, were isolated from tilia flowers, goat willow leaves, black currant leaves and red currant leaves. All together, the tested compounds represented the major tannin types (procyanidins and prodelphinidins) and flavonoid types (flavonols, flavones and flavanones). The larval exsheathment inhibition assay (LEIA) was used to assess their in vitro effects on Haemonchus contortus third stage larvae. Arbutin, vanillic acid, and taxifolin proved to be ineffective whereas naringenin, quercetin and luteolin were highly effective at 250 μM concentrations. Procyanidin (PC) tannins tended to be less active than prodelphinidin tannins (PD). Experiments with combinations of tannins and quercetin or luteolin revealed for the first time the existence of synergistic AH effects between tannins and flavonoid monomers. They also provided evidence that synergistic effects appear to occur at slightly lower concentrations of PC than PD. This suggests that the AH activity of condensed tannins can be significantly enhanced by the addition of quercetin or luteolin. This information may prove useful for plant breeding or selection and for designing optimal feed mixtures.
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•Tannins and flavonoids showed anti-parasitic effects against Haemonchus contortus.•This is the first report of their synergistic effects on larval exsheathment.•Flavonoids enhanced especially the anthelmintic activities of procyanidin tannins.
The Alpine goat (Capra aegagrus hircus) is parasitized by the barber pole worm (Haemonchus contortus). Hematological parameters from transcript and metagenome analysis in the host are reflective of ...infestation. We explored comparisons between blood samples of control, infected, infected zoledronic acid-treated, and infected antibody (anti-γδ T cells) treated wethers under controlled conditions. Seven days post-inoculation (dpi), we identified 7,627 transcripts associated with the different treatment types. Microbiome measurements at 7 dpi revealed fewer raw read counts across all treatments and a less diverse microbial flora than at 21 dpi. This study identifies treatment specific transcripts and an increase in microflora abundance and diversity as wethers age. Further, F/B ratio reflect health, based on depression or elevation above thresholds defined by the baseline of non-infected controls. Forty Alpine wethers were studied where blood samples were collected from five goats in four treatment groups on 7 dpi and 21 dpi. Transcript and microbiome profiles were obtained using the Partek Flow (St. Louis, Missouri, USA) software suites pipelines. Inflammation comparisons were based on the Firmicutes/Bacteriodetes ratios that are calculated as well as the reduction of microbial diversity.
Plants containing condensed tannins (CTs) may hold promise as alternatives to synthetic anthelmintic (AH) drugs for controlling gastrointestinal nematodes (GINs). However, the structural features ...that contribute to the AH activities of CTs remain elusive. This study probed the relationships between CT structures and their AH activities. Eighteen plant resources were selected on the basis of their diverse CT structures. From each plant resource, two CT fractions were isolated and their in vitro AH activities were measured with the larval exsheathment inhibition assay, which was applied to Haemonchus contortus and Trichostrongylus colubriformis. Calculation of mean EC50 values indicated that H. contortus was more susceptible than T. colubriformis to the different fractions and that the F1 fractions were less efficient than the F2 ones, as indicated by the respective mean values for H. contortus, F1 = 136.9 ± 74.1 μg/mL and F2 = 108.1 ± 53.2 μg/mL, and for T. colubriformis, F1 = 233 ± 54.3 μg/mL and F2 = 166 ± 39.9 μg/mL. The results showed that the AH activity against H. contortus was associated with the monomeric subunits that give rise to prodelphinidins (P < 0.05) and with CT polymer size (P < 0.10). However, for T. colubriformis AH activity was correlated only with prodelphinidins (P < 0.05). These results suggest that CTs have different modes of action against different parasite species.
The variable anthelmintic efficacy of condensed tannins (CT) against gastrointestinal nematodes may depend on CT concentration, composition, or fate along the digestive tract. We analyzed CT ...concentration and composition by acetone-HCl-butanol and thiolysis coupled to HPLC-MS in digesta and feces of lambs. Lambs had been infected with Haemonchus contortus and Trichostrongylus colubriformis and received sainfoin pellets and hazelnut skins of contrasting prodelphinidin/procyanidin ratios. The digesta and feces had lower CT concentrations than the original feeds but similar concentration patterns across the digestive compartments. The changes in assayable CT concentrations between rumen, abomasum, and small intestine may be due to complex formation between CT and other dietary components. However, the large CT disappearance (61-85%) from feed to feces could also indicate that CT may have been structurally modified, degraded, or absorbed during digestion. Interestingly, there were no changes in the structural features of assayable CT in the digesta.
The focus of this research was to investigate how tannin extract from black tea influenced the hematological and histopathological evaluations of male rabbits fed a mycotoxin-contaminated feed, ...including 17 ppb aflatoxin, 5 ppb ochratoxin and 2 ppb fumonisin. A total of 28 local male rabbits were allocated into four groups, the first of which was a control group. The second was fed a Mycotoxin-contaminated meal. The third was given a Mycotoxin feeding with tannin extracts (125mg/mL per head) administered orally, while the fourth was fed a Mycotoxin contaminated diet with tannin extracts (250 mg/mL per head) given orally. The findings revealed that tannin extracts seemed to have a significant positive impact on haematological results, particularly RBCs and WBCs, throughout the period; however, the 250 mg/mL dose showed no significant differences in Hb levels. Nonetheless, as compared to the Mycotoxin group, the histopathological sections of tannin extract demonstrated a reduction in the toxicity of the Mycotoxin diet on the liver and kidney tissues; conversely, the tissue sections of the control animals showed no abnormalities. In male rabbits fed contaminated Mycotoxin diets, tannin extract from black tea was found to have a favourable impact on hematological activities and vital organs such as the liver and kidney.
Abstract
Resistance to internal parasites (IP) is important in the sustainability of a meat goat enterprise. Langston University (LU) and the American Kiko Goat Association conducted a ...SecondGeneration Buck Performance Test in 2019. The performance test measured fecal egg count (FEC) and packed-cell volume (PCV) in a natural challenge of 6 wk on pasture (PAS) and in an artificial challenge in dry-lot confinement (CON). Seventy-seven Kiko bucks less than 1 yr of age completed both PAS and CON. The PAS was conducted on a 23-ha pasture with native grasses and forbs. Bucks were supplemented at 0.5% BW (25.8±0.18 kg) daily to facilitate visual inspection of animals. CON was conducted at LU’s testing facility. Bucks were sampled every 2 wk in PAS. In CON, bucks were sampled on d 29, 34, and 38 following an artificial challenge with each buck receiving 7,000 L3 Haemonchus contortus larvae. Average FEC and PCV for each buck for PAS and CON were analyzed. The correlation between FEC-PAS and PCV-PAS was -0.283 (P < 0.05), which is almost identical to the correlation between FEC-CON and PCV-CON (r=-0.280, P < 0.05). The Spearman rank correlation between FEC-PAS and FEC-CON was 0.069 (P > 0.50). However, the Spearman rank correlation between PCV-PAS and PCV-CON was 0.376 (P < 0.01). Using mixed model methods, the means for FEC-CON and FEC-PAS were similar (1,428 vs 1,698±169 epg for CON and PAS, respectively). However, PCV were different (P < 0.01), with 28.3 vs. 20.7±0.34 for CON and PAS, respectively. Pasture PCV was a predictor of PCV in confinement and vice versa; however, that was not true for FEC, indicating that FEC in PAS and in CON may be two separate traits. Future buck performance tests should incorporate pasture and confinement phases to more precisely identify superior bucks for IP resistance.
Resistance to internal parasites (IP) is important in the sustainability of a meat goat enterprise. Langston University (LU) and the American Kiko Goat Association conducted a SecondGeneration Buck ...Performance Test in 2019. The performance test measured fecal egg count (FEC) and packed-cell volume (PCV) in a natural challenge of 6 wk on pasture (PAS) and in an artificial challenge in dry-lot confinement (CON). Seventy-seven Kiko bucks less than 1 yr of age completed both PAS and CON. The PAS was conducted on a 23-ha pasture with native grasses and forbs. Bucks were supplemented at 0.5% BW (25.8±0.18 kg) daily to facilitate visual inspection of animals. CON was conducted at LU's testing facility. Bucks were sampled every 2 wk in PAS. In CON, bucks were sampled on d 29, 34, and 38 following an artificial challenge with each buck receiving 7,000 L3 Haemonchus contortus larvae. Average FEC and PCV for each buck for PAS and CON were analyzed. The correlation between FEC-PAS and PCV-PAS was -0.283 (P < 0.05), which is almost identical to the correlation between FEC-CON and PCV-CON (r=-0.280, P < 0.05). The Spearman rank correlation between FEC-PAS and FEC-CON was 0.069 (P > 0.50). However, the Spearman rank correlation between PCVPAS and PCV-CON was 0.376 (P < 0.01). Using mixed model methods, the means for FEC-CON and FECPAS were similar (1,428 vs 1,698±169 epg for CON and PAS, respectively). However, PCV were different (P < 0.01), with 28.3 vs. 20.7±0.34 for CON and PAS, respectively. Pasture PCV was a predictor of PCV in confinement and vice versa; however, that was not true for FEC, indicating that FEC in PAS and in CON may be two separate traits. Future buck performance tests should incorporate pasture and confinement phases to more precisely identify superior bucks for IP resistance.
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•Efficacy of sainfoin on a multiresistant to anthelmintic strain of H. contortus.•Combining tannin-containing diet and oral administration of macrocyclic lactones could have negative ...consequences.•Need for further experiments to study the interactions between tannin containing diet and anthelmintic drugs.
The worldwide spread of resistance to anthelmintic (AH) drugs in gastrointestinal nematodes (GINs) imposes to explore alternative solutions. Amongst those, the possible use of tannin-containing nutraceuticals appears as a relevant option to replace (or decrease the frequency of) chemical-based treatments. Our objectives were to test the AH efficacy of sainfoin pellets against a multiresistant strain of Haemonchus contortus in experimentally infected lambs and to examine possible interaction between ivermectin (IVM) and condensed tannins (CT)-rich ressource.
In vivo study was performed with twenty-four lambs were inoculated (Day 0) with multiresistant H. contortus infective larvae. On D21 Post-Infection, the lambs were assigned to two dietary treatments (sainfoin vs lucerne control pellets). On D39, half of the animals per group received 0.25ml/kg of an oral ivermectin treatment. On D47, animals were slaughtered to count worms. The consumption of sainfoin was associated with higher packed cell volume (PCV) values (P<0.05) and reduced faecal egg counts (FECs) (P<0.05). For the experimental feeding period, FECs were overall reduced by 50% in the sainfoin group. The diet did not have significant effect on the worm number but sainfoin significantly reduced female fertility. Decrease in plasma IVM concentrations was observed in the sainfoin-fed animals and was associated with a decrease of IVM efficiency when compared with the control group. Incubating tannin in vitro with ivermectin and rumen fluid showed a blocking of ivermectin by the tannins. This suggests that tannins lower the IVM intestinal absorption compromising thereby drug plasma bioavailability and efficacy.
Tannin-containing nutraceuticals alter the biology of multiresistant nematodes, thus representing an option for their sustainable control. In vivo and in vitro interactions between nutraceuticals and chemicals impose caution when both tannin-rich diet and drug-based treatments are combined. Further studies are required to clarify the mechanisms that support such interactions.
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