Anthelmintic effect and tissue alterations induced in vitro by hydrolysable tannins on the adult stage of the gastrointestinal nematode Haemonchus contortus

In Vitro and In Silico Anthelmintic Activity of Extracts of Lannea kerstingii and Ficus thonningii on Heligmosomoides polygyrus

Background: The aim of this study was to assess the anthelmintic activity of Lannea kerstingii and Ficus thonningii, on a nematode model, to promote their use in the Cameroonian pharmacopoeia for the treatment of helminthiases. Methods: One nematode was used, Heligmosomoides polygyrus. First, the effect of the extracts on the eggs and larval stages (L1, L2, and L3) of H. polygyrus was evaluated, 100 μL of extract and 100 μL of parasite suspension (containing 50 eggs) were mixed in a 96-well microplate. The 96-well microplate was incubated for 20 h at 25°C in the WMicroTracker which measures the motility of the worms at various concentrations. Finally, docking studies were conducted by using the Glide module in Schrodinger Maestro. Results: The ethanolic extract of L. kerstingii with the half maximal inhibitory concentration (IC50) of 0.1371 mg/mL produced a higher ovicidal effect than the effect produced by other extracts of these plants. However, with an IC50 of 0.31 mg/mL, the aqueous extract of F. thonningii showed the greatest effect on the L2 stage. The aqueous and ethanolic extracts of L. kerstingii and F. thonningii inhibited the development of the L3 larvae of H. polygyrus with a better effect for the ethanolic extracts. Conclusion: The use of L. kerstingii and F. thonningii for the treatment of helminthiasis has been proved in vitro and in silico by this research. However, more research is required, especially on the acute toxicity and in vivo anthelmintic efficacy to validate this scientific investigation.

Phytochemical Study of the Anthelminthic Potential of Guadeloupean Plant Biodiversity

Gastrointestinal parasitism is a major health and welfare problem in ruminants. Synthetic chemical anthelmintic drugs have led to the emergence of resistance in gastrointestinal strongyles, inducing the search for alternatives to control the infections that affect ruminants. The objective of this work was to evaluate the anthelmintic potential of plant extracts against Haemonchus contortus Rudolphi. Three plants of the Guadeloupean biodiversity, Momordica charantia L., Carica papaya L. and Sargassum spp., were selected based on their high polyphenolic content and natural abundance. The phytochemistry of plants was explored, a biological assay against the parasite H. contortus was carried out, and several hypotheses about the way of action were proposed by an innovative electrochemical screening method.

Comparison of the first time detected Oesophagostomum asperum with Oesophagostomum columbianum in sheep and goats in Bangladesh based on the trinity: Morphology, morphometry and genetic diversity

Oesophagostomum spp. (Family: Chabertiidae) is keeping a low profile in terms of severity in Bangladesh while maintaining economic loss through disguise within sheep and goats. The study was performed to identify prevalence, confirmation of species through morphology and morphometry followed by phylogeny using ITS2 and COX1 genes. In total 384 slaughterhouse-sourced small and large intestines were pooled from Mymensingh, Kishoreganj, Netrokona, Sherpur and Tangail districts of Mymensingh division. Followed by isolation, O. columbianum and O. asperum were identified following their key morphological features. Notably, O. asperum was first time detected in Bangladesh. The overall prevalence of Oesophagostomum spp. was found 60.93%. The prevalence of O. columbianum (64.95%) was almost double than that of O. asperum (35.04%). Among several characters, only the distance between anus to tail tip showed a significant morphological disparity in female. The Neighbor-joining (NJ) phylogenic trees based on ITS2 and COX1 genes confirmed the study species. The first time identified O. asperum along with morphometry and phylogeny will add value to the fact that nematodes are invisibly present with high prevalence in this country. This study will help to draw specific attention to command a practical control strategy for intervening in economic loss.

In vitro culture of parasitic stages of Haemonchus contortus

Haemonchus contortus is a constraint to sheep production. Seeking to reduce the use of hosts and produce parasitic stages in large-scale, a 42-day in vitro culture protocol of H. contortus third-stage larvae was optimized using Dulbecco's modified Eagle's medium (DMEM). In cell-free culture, larvae were maintained at 39.6°C, in acidic media (pH 6.1) for 3 or 6 days with Δ4-dafachronic acid followed by DMEM pH 7.4 supplemented or not with Fildes' reagent. In DMEM pH 7.4 at 37°C, supplementation with Caco-2 cells was compared to Fildes. On Day 14, fourth-stage larvae (L4) development rates in acidic media supplemented (86.8-88.4%) or not (74.4-77.8%) with Fildes and in Caco-2 cell co-culture (92.6%) were similar, and superior to DMEM pH 7.4 with Fildes (0.0%). On Day 21, Caco-2 cell co-culture resulted in higher larvae differentiation (25.0%) and lower degeneration (13.9%) compared to acidic media (1.5-8.1% and 48.6-69.9%, respectively). This is the first report of prolonged in vitro culture of H. contortus larvae using commercial media in co-culture with Caco-2 cells. Although no progression to the adult stage, Caco-2 cell co-culture resulted in morphological differentiation of H. contortus L4 and larval viability for up to 28 days.

Improvement of cell suspension cultures of transformed and untransformed Carica papaya cell lines, towards the development of an antiparasitic product against the gastrointestinal nematode Haemonchus contortus

Parasitic diseases have a major impact on human and animal health worldwide. Despite the availability of effective anti-parasitic drugs, their excessive and uncontrolled use has promoted the emergence of drug resistance, severely affecting ecosystems and human health. Thus, developing environmentally friendly antiparasitic treatments is urgently needed. Carica papaya has shown promising effects against infectious diseases. C. papaya embryogenic calluses were genetically modified by our research team to insert immunogenic peptides with the goal of developing an oral anti-cysticercosis vaccine. Among these callus cell lines, one labeled as CF-23, which expresses the KETc7 immunogenic peptide, induced the highest protection levels against experimental cysticercosis. In the process of designing a natural antiparasitic product based on C. papaya that simultaneously induced immunity against cysticercosis, both transformed (SF-23) and untransformed (SF-WT) suspension cultures were produced and optimized. Our results showed a better duplication time (td) for SF-23 (6.9 days) than SF-WT (13.02 days); thus, the SF-23 line was selected for scale-up in a 2-L airlift bioreactor, reaching a td of 4.4 days. This is the first time that a transgenic line of C. papaya has been grown in an airlift bioreactor, highlighting its potential for scale-up cultivation in this type of reactor. Considering the previously reported nematocidal activity of C. papaya tissues, their activity against the nematode Haemonchus contortus of aqueous extracts of SF-WT and SF-23 was explored in this study, with promising results. The information herein reported will allow us to continue the cultivation of the transgenic cell suspension line of C. papaya under reproducible conditions, to develop a new anti-parasitic product.

The prevalence of intestinal parasite infections in goats from smallholder farms in Northern Thailand

The present study determined the prevalence of gastrointestinal (GI) parasites in small ruminants kept in smallholder farms in Phitsanulok, Northern Thailand. A total of 885 goats from 31 smallholder farms were selected randomly between May 2019 to January 2020. Fecal samples were collected to estimate fecal egg counts and oocysts counts using the modified McMaster technique. Furthermore, pooled fecal samples from each of the farms were cultured in order to differentiate third-stage larvae of nematode. Examination of fecal samples revealed that 885 were positive for one or more parasites, giving an overall prevalence of 87.2 %, of which 38.6 % were infected with one and 48.6 % with multiple parasite. Strongyles and Eimeria oocysts were the most prevalent. Haemonchus contortus and Strongyloides papillosus were the predominant species based on the percentage of larvae in fecal cultures. Tapeworm eggs were encountered in 14.2 % of all samples. No significant difference in gastrointestinal parasite prevalence was associated with sex of the host. Infection was significantly (P = 0.009) highest in poor body conditioned goats (72.0 %) as compared to moderate (48.9 %) and good body conditioned (50.0 %) goats. This report on prevalence of GI parasites of small ruminants in smallholder farms in Northern Thailand reveals a high endoparasitic infections that appeared well-adapted to environmental conditions. Further studies on endoparasite control are required to establish the impact of parasitism on productive performance, including monitoring control parasite programs are needed for better health and productivity.

The effect of pumpkin seed cake and ground cloves (Syzygium aromaticum) supplementation on gastrointestinal nematode egg shedding in sheep

The aim of this study was to evaluate the effect of feed additives (pumpkin seed cake and cloves) on the egg excretion of gastrointestinal nematodes (GIN) in sheep. Thirty ewes naturally infected with GIN were randomly selected from a flock and assigned to the following groups of 10 animals each: clove group (received 1.8 g ground cloves/ewe/day, for 7 days), pumpkin seed cake group (200 g pumpkin seed cake/ewe/day, for 7 days) and control group. Before starting the study, on day 0, and 5 days after the 7-day supplementation, on day 12, the body condition and FAMACHA scores were assessed and individual faecal egg counts (FEC) were performed. The mean body condition and the FAMACHA scores did not change significantly between day 0 and 12 with the exception of a significantly deteriorated FAMACHA score in the clove group. The percentage reduction of FEC was 40.7% on day 12 in the clove group and 52.9% in the pumpkin seed cake group. In the control group, FEC increased by 8.7%. A coproculture of faecal samples from four of the most infected animals on day 0 revealed Trichostrongylus spp. larvae L3 in all four selected ewes, Ostertagia spp. and Cooperia spp. in three and Haemonchus contortus in one ewe. These results are promising and encourage further studies aimed to evaluate the possibility that these plant supplements could be a complementary method for parasite control, thus reducing the need for chemotherapy.

Anthelmintic resistance: is a solution possible?

More than 50 years after anthelmintic resistance was first identified, its prevalence and impact on the animal production industry continues to increase across the world. The term "anthelmintic resistance" (AR) can be briefly defined as the reduction in efficacy of a certain dose of anthelmintic drugs (AH) in eliminating the presence of a parasite population that was previously susceptible. The main aim of this study is to examine anthelmintic resistance in domestic herbivores. There are numerous factors playing a role in the development of AR, but the most important is livestock management. The price of AH and the need to treat a high number of animals mean that farmers face significant costs in this regard, yet, since 1981, little progress has been made in the discovery of new molecules and the time and cost required to bring a new AH to market has increased dramatically in recent decades. Furthermore, resistance has also emerged for new AH, such as monepantel or derquantel. Consequently, ruminant parasitism cannot be controlled solely by using synthetic chemicals. A change in approach is needed, using a range of preventive measures in order to achieve a sustainable control programme. The use of nematophagous fungi or of plant extracts rich in compounds with anthelmintic properties, such as terpenes, condensed tannins, or flavonoids, represent potential alternatives. Nevertheless, although new approaches are showing promising results, there is still much to do. More research focused on the control of AR is needed.

Anthelmintic effect of Indigofera tinctoria L on Haemonchus contortus obtained from sheep in Indonesia

Background and Aim:

Hemonchosis has resulted in huge economic losses for sheep farmers worldwide. Secondary metabolite compounds from Indigofera tinctoria L. can be used as anthelmintics. This study aimed to evaluate the in vitro and in vivo effects of I. tinctoria L. aqueous extract (IAE) as an anthelmintic against adult Haemonchus contortus isolated from sheep.

Materials and Methods:

Ten active adult worms were placed in each Petri dish containing 25 mL of IAE, each having a different concentration of IAE (at concentrations 100, 120, 140, 160, 180, 200, and 220 mg/mL). Each experiment was repeated. The positive control used 1% albendazole, and the negative control used 0.62% saline water. The number of immobile worms and the time of mortality were recorded after 2, 4, 6, and 8 h. The dead worms were subsequently tested using scanning electron microscopy (SEM) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In the in vivo study, 15 sheep with an average fecal egg count (FEC) of 1000 eggs per gram were treated with IAE for 9 days: Group A (negative control, saline water 0.62%), Group B (21 mg/mL), Group C (41 mg/mL), Group D (62 mg/mL), and Group E (positive control, albendazole 100 mg/mL). Measurements of the body weight, FEC reduction test, and hematology testing were performed on days 0, 7, and 14. SEM was performed using worms found from the abomasum of slaughtered sheep.

Results:

The leaves of I. tinctoria L. contained a number of secondary metabolites, including total tannins, saponins, flavonoids, and alkaloids. The most effective concentration that killed the adult H. contortus worms was 220 mg/mL (93.33% mortality) after 8 h of treatment. The electrophoresis results showed that the protein band at a dose of 22% was less than that of the control. The highest FECR value of the treatment group on the 14^th day after treatment was at a dose of 62 mg/mL. The highest weight gain as well as the highest increased hemoglobin (Hb), packed cell volume (PCV), and total erythrocyte count (TEC) values on the 14^th day after treatment were at a dose of 41 mg/mL. The SEM results showed that IAE treatment caused the worms’ anterior parts to become wrinkled with thick creases and cuticle abrasion (in vitro) and the anterior part to shrink along with the presence of aggregates in the worm cuticle (in vivo).

Conclusion:

The aqueous extract of I. tinctoria contains tannins, saponins, flavonoids, and alkaloids and has an anthelmintic effect with decreased FEC, increased weight gain, Hb, PCV, and TEC, causing damage to the worms’ body and reducing the protein profile of adult H. contortus worms.

Nutritional Aspects of Ecologically Relevant Phytochemicals in Ruminant Production

This review provides an update of ecologically relevant phytochemicals for ruminant production, focusing on their contribution to advancing nutrition. Phytochemicals embody a broad spectrum of chemical components that influence resource competence and biological advantage in determining plant species' distribution and density in different ecosystems. These natural compounds also often act as plant defensive chemicals against predatorial microbes, insects, and herbivores. They may modulate or exacerbate microbial transactions in the gastrointestinal tract and physiological responses in ruminant microbiomes. To harness their production-enhancing characteristics, phytochemicals have been actively researched as feed additives to manipulate ruminal fermentation and establish other phytochemoprophylactic (prevent animal diseases) and phytochemotherapeutic (treat animal diseases) roles. However, phytochemical-host interactions, the exact mechanism of action, and their effects require more profound elucidation to provide definitive recommendations for ruminant production. The majority of phytochemicals of nutritional and pharmacological interest are typically classified as flavonoids (9%), terpenoids (55%), and alkaloids (36%). Within flavonoids, polyphenolics (e.g., hydrolyzable and condensed tannins) have many benefits to ruminants, including reducing methane (CH4) emission, gastrointestinal nematode parasitism, and ruminal proteolysis. Within terpenoids, saponins and essential oils also mitigate CH4 emission, but triterpenoid saponins have rich biochemical structures with many clinical benefits in humans. The anti-methanogenic property in ruminants is variable because of the simultaneous targeting of several physiological pathways. This may explain saponin-containing forages' relative safety for long-term use and describe associated molecular interactions on all ruminant metabolism phases. Alkaloids are N-containing compounds with vast pharmacological properties currently used to treat humans, but their phytochemical usage as feed additives in ruminants has yet to be exploited as they may act as ghost compounds alongside other phytochemicals of known importance. We discussed strategic recommendations for phytochemicals to support sustainable ruminant production, such as replacements for antibiotics and anthelmintics. Topics that merit further examination are discussed and include the role of fresh forages vis-à-vis processed feeds in confined ruminant operations. Applications and benefits of phytochemicals to humankind are yet to be fully understood or utilized. Scientific explorations have provided promising results, pending thorough vetting before primetime use, such that academic and commercial interests in the technology are fully adopted.

Plant Secondary Metabolites: An Opportunity for Circular Economy

Moving toward a more sustainable development, a pivotal role is played by circular economy and a smarter waste management. Industrial wastes from plants offer a wide spectrum of possibilities for their valorization, still being enriched in high added-value molecules, such as secondary metabolites (SMs). The current review provides an overview of the most common SM classes (chemical structures, classification, biological activities) present in different plant waste/by-products and their potential use in various fields. A bibliographic survey was carried out, taking into account 99 research articles (from 2006 to 2020), summarizing all the information about waste type, its plant source, industrial sector of provenience, contained SMs, reported bioactivities, and proposals for its valorization. This survey highlighted that a great deal of the current publications are focused on the exploitation of plant wastes in human healthcare and food (including cosmetic, pharmaceutical, nutraceutical and food additives). However, as summarized in this review, plant SMs also possess an enormous potential for further uses. Accordingly, an increasing number of investigations on neglected plant matrices and their use in areas such as veterinary science or agriculture are expected, considering also the need to implement "greener" practices in the latter sector.

Nematicidal Effect and Histological Modifications Induced by Hydrolysable Tannin Extract on the Third-Stage Infective Larvae of Haemonchus contortus

Haemonchus contortus is the most frequent and most important nematode parasite in the ruminants production of tropical and subtropical regions. There are strains resistant to all families of available anthelmintics. Consequently, the conduction of research to find other resources that allow effective control of this parasitic disease, preferably focusing on green production, is necessary. The aim of this study was to evaluate the effect of hydrolysable tannin extract (HTE) on larvae 3 (L3) of H. contortus in vitro. L3 were exposed to different HTE concentrations and times. In addition, both light and scanning electron microscopy were used to explore physical damage on L3 subjected to HTE activity. After 72 h of incubation, the mean lethal concentration of HTE was 2 mg/mL; this concentration has been previously referred to as safe for consumption in cattle. Scanning electron microscopy revealed H. contortus L3 destruction, damage was evident by separation of the sheath mainly in the cervical and caudal regions of the larva and by rupture of the cuticle with larval evisceration. Our results suggest that hydrolysable tannin extract from chestnut could be considered as a green alternative for parasitic control in ruminants.

Tannin supplementation modulates the composition and function of ruminal microbiome in lambs infected with gastrointestinal nematodes

This study was carried out to evaluate the effects of tannin supplementation on ruminal microbiota of sixteen lambs infected and non-infected with Haemonchus contortus and Trichostrongylus colubriformis. Animals were fed with hay, concentrate and supplemented with Acacia mearnsii (A. mearnsii). The animals were divided into four treatments: two control groups without infection, either receiving A. mearnsii (C+) or not (C-), and two infected groups, one with A. mearnsii (I+) and another without A. mearnsii (I-). Ruminal short-chain fatty acids (SCFA) and metagenome sequencing of ruminal microbiota were used to evaluate the effect of tannin and infection on ruminal microbiome. For SCFA, differences were observed only with A. mearnsii. Total SCFA and acetate molar percentage were decreased in C+ and I+ (P<0.05). Butyrate, valerate and isovalerate were higher in lambs that received A. mearnsii in the diet (P<0.05). The infection changed the microbiome structure and decreased the abundance of butyrate-producing microorganisms. In addition, A. mearnsii supplementation also affected the structure the microbial community, increasing the diversity and abundance of the butyrate-producing and probiotics bacteria, amino acid metabolic pathways, purine, pyrimidine and sphingolipid metabolism. Together, our findings indicate that A. mearnsii supplementation modulates important groups related to nitrogen, amino acid, purine and pyrimidine metabolism, in rumen microbiome, affected by gastrointestinal nematodes infection in lambs.

In vitro anthelmintic activity of aqueous and ethanol extracts of Paraserianthes falcataria bark waste against Haemonchus contortus obtained from a local slaughterhouse in Indonesia

AIM

This study was conducted to determine the anthelmintic activity of aqueous and ethanol extracts of Paraserianthes falcataria bark against Haemonchus contortus.

MATERIALS AND METHODS

Ethanol extract of bark (E.E.B.) waste and aqueous extract of bark (A.E.B.) waste of P. falcataria (at concentrations 0, 0.2, 0.4, 0.8, 1, 2.5, and 5%) and albendazole (2 mg/ml) as the positive control were placed in separate Petri dishes (50 mm). Twenty H. contortus worms were placed in Petri dishes and incubated at 37°C for 0.5, 1, 2, 3, 4, 5, 6, and 12 h. Mortality of each worm was ensured by pressing the body of the worm with a pair of tweezers and keeping it in lukewarm water for 5 min before declaring it dead. Mortality is defined as amount of death individuals and time of mortality of each worm was recorded. The parasites were then observed using scanning electron microscopy (SEM) at an accelerating voltage of 15 Kv. Statistical analysis was performed using SPSS 21.0 software, two-way ANOVA followed by Tukey's test to detect significant differences (p<0.05). The result was expressed as the mean ± standard deviation.

RESULTS

The E.E.B. and A.E.B. of P. falcataria contained active compounds, such as tannin, alkaloid, flavonoid, saponin, steroid, and triterpenoid. E.E.B. had a higher content of phenol, while A.E.B. had a higher content of flavonoid. In this study, P. falcataria showed a significant effect (p=0.00) on H. contortus in vitro. E.E.B. (0.8%) was able to exterminate H. contortus completely after 6 h, more effective than A.E.B. (5%) while the positive control requires (2 mg/ml) after 2 h. SEM analysis of the worm treated with E.E.B. and A.E.B. showed damaged cuticle structure.

CONCLUSION

The aqueous and ethanol extracts of P. falcataria bark waste demonstrated anthelmintic activity against H. contortus.

Chemical constituents of Calotropis procera latex and ultrastructural effects on Haemonchus contortus

Abstract This study aimed to evaluate the anthelmintic and ultrastructural effects of Calotropis procera latex on Haemonchus contortus. C. procera latex was twice centrifuged at 10,000×g and dialyzed to obtain a fraction rich in proteins, named LP (latex protein), and at 3,000 rpm to obtain a fraction rich in secondary metabolites, named LNP (latex non-protein). Specimens of H. contortus exposed to LNP, LP and PBS in the Adult Worm Motility Test (AWMT) were submitted to scanning (SEM) and transmission (TEM) electron microscopy to verify changes in their ultrastructure. Phytochemical tests in the LNP indicated the presence of phenols, steroids, alkaloids and cardenolides. High-Performance Liquid Chromatography (HPLC) characterized the presence of the compounds gallic acid and quercetin in the LNP. The protein content in the LP was 43.1 ± 1.1 mg/mL and 7.7 ± 0.3 mg/mL in LNP. In AWMT, LNP and LP inhibited the motility of 100% of the nematodes, with LNP being more effective than LP and ivermectin more effective than both (p <0.05). Cuticle changes were observed by SEM and TEM in nematodes treated with LP and LNP. Calotropis procera latex has anthelmintic effects against H. contortus, causing damage to its cuticle and other alterations in its ultrastructure.