Papers by Marcelo Molento
DOAJ (DOAJ: Directory of Open Access Journals), May 1, 2022
Chemico-Biological Interactions
Parasitology International
Strategic helminth control in adult cattle would hardly impose sufficient selection pressure to p... more Strategic helminth control in adult cattle would hardly impose sufficient selection pressure to parasite populations but reports of resistance against macrocyclic lactone (ML) based-products have been confirmed worldwide. The objective of this study was to evaluate the scientific literature of ML resistance (< 90.0% efficiency) in helminths of cattle from 2001 (the first report) to 2020 in Brazil. Additional to the data, we studied the correlation of parasite control practices based on a questionnaire given to 32 farmers. The search returned 246 reports and 21 full articles were selected. From these, a Wordcloud and a Keyword Co-occurrence Network graph were created. The published data revealed that most of the studies (19/21) reported multi-species (Cooperia spp., Haemonchus sp., Oesophagostomum radiatum, Trichostrongylus sp.) resistance to ML. None of the reports described the treatment frequency in the tested farms. As for the questionnaire, the majority of farmers (> 70.0%) responded that they rotate products after treatment, animals are treated monthly or biweekly (58.0%), treatments are based on visual evaluation (coat condition, ectoparasite infestation), and that in 94.0% of the times farmers treat all animals. Moreover, farmers use ML in association with potent acaricides (cypermethrin, chlorpyriphos, fluazuron) in more than 90.0% of the times (15/16). It was observed that this regimen was used to prevent and control the cattle-tick Rhipicephalus microplus (90.0%) and the horn-fly, Haematobia irritans (30.0%) infestations. We conclude that the most important factor for nematode resistance was the high level of ML exposure of up to 16 times/year, in combination with acaricides to control ticks and to a lesser extent to control horn-flies. Therefore, selection of helminth populations in cattle in Brazil can be considered secondary to ectoparasite control. The present analysis is critical, as one the most widespread recommendations to avoid drug resistance is to reduce the use of long-acting compounds, due to their extended persistent periods, increasing parasite selection. Moreover, a more serious attitude must be taken regarding parasite control strategies for livestock, reinforcing that health protocols should be based on single acaricidal products whenever possible. Complementary, selective evaluations based on transient threshold population abundance must be enforced to reduce treatment frequency, reducing parasite selection and animal distress.
Archives of Veterinary Science, 2017
Acta Tropica, 2021
Haemonchus contortus, a blood-sucking parasite of small ruminants, produces very important econom... more Haemonchus contortus, a blood-sucking parasite of small ruminants, produces very important economic losses in the productive sector. This abomasum parasite has become resistant to most commercial drugs worldwide, and alternatives to fight this problem are urgently needed. Essential oils (EO) are a complex mixture of volatile secondary metabolites, composed mainly by terpenoids and phenolic compounds, from plants that have several pharmacological properties, including anthelmintic activity. Particularly, citrus peel is a source of cold-pressed EO, where limonene is its major component, and can be used as an additional food component for ruminants. The aim of the present work was to determine the in vitro anthelmintic activity of EO from Citrus bergamia (EOB), C. x paradisii (EOG) and limonene against the benzimidazole-susceptible Kirby isolate of H. contortus, using the egg hatch test (EHT) and the exsheathed third stage larval motility test (XLMT) using a WMicroTracker equipment. Albendazole (ABZ) and monepantel (MON) were used as positive controls. The 50% inhibitory concentrations (IC50) in XLMT were 8.77 and 13.88 µg/ml for EOB and EOG respectively, after an incubation of 72 h. An interesting observation on XLMT resulted when the positive controls were tested on the same plate, but in different well of the EOB. The volatile components of the EO significantly influenced (P < 0.05) the percentage of larval motility, reducing values from 66.9 to 19.6% for ABZ, and from 72.8 to 33.7% for MON, when comparing the activity of positive controls in a control plate without EO. The in vitro anthelmintic activity of EOB and EOG shows that they could be interesting candidates for nematode control. It is still necessary additional studies against the adult stage of H. contortus in efficacy trials in infected animals to validate their anthelmintic activity.
Veterinary Parasitology, 2021
Mentha villosa Hubs., M. x piperita and their bioactives against gastrointestinal nematodes of ru... more Mentha villosa Hubs., M. x piperita and their bioactives against gastrointestinal nematodes of ruminants and the potential as drug enhancers Bruno Batista Bortoluzzi (Conceptualization) (Methodology) (Investigation) (Validation) (Writing-original draft), Andréia Buzatti (Methodology) (Investigation) (Validation), Amanda Chaaban (Methodology) (Resources), Izanara Cristine Pritsch (Writingreview and editing), Alan dos Anjos (Software) (Formal analysis) (Data curation), Roger Raup Cipriano (Methodology) (Validation), Cícero Deschamps (Methodology) (Resources), Marcelo Beltrão Molento (Conceptualization) (Investigation) (Writing-review and editing) (Supervision)
Archives of Veterinary Science, 2020
Os helmintos gastrintestinais de cães são uma das principais fontes de contaminação ambiental e a... more Os helmintos gastrintestinais de cães são uma das principais fontes de contaminação ambiental e agressão aos animais. O controle dessas parasitoses é importante tanto para a saúde animal como humana. Helmintos dos gêneros Ancylostoma e Toxocara estão envolvidos em casos de zoonoses por exemplo, causando respectivamente a larva migrans cutânea e visceral. Tendo em vista a importância desses agentes etiológicos, o presente estudo tem por objetivo calcular e avaliar a sensibilidade de três diferentes técnicas coproparasitológicas comumente utilizadas na rotina clínica. O objetivo é determinar qual técnica possui o diagnóstico mais sensível para helmintos de cães. Para tal, foram utilizadas 81 amostras de fezes de cães, entre eles adultos e filhotes acima de seis meses, provenientes do Centro de Bem-estar Animal do Município de São Francisco do Sul, SC. Todas as amostras passaram por processamento para três técnicas coproparasitológicas, sendo elas flutuação em solução saturada de NaCl ...
Semina: Ciências Agrárias, 2021
Sheep farming is of great importance in generating income to smallholders in semi-arid areas worl... more Sheep farming is of great importance in generating income to smallholders in semi-arid areas worldwide. Gastrointestinal helminths cause important damage to the animals with poor welfare conditions, impacting in local economies. The objective of this work was to evaluate the FAMACHA method (FMC) in a herd of 60 Santa Inês from Paraíba, Brazil, and to compare the data from previous production years. In order to determine anemic sheep, FMC chart was used in biweekly evaluations for 12 months by trained personnel. Blood and fecal samples were collected monthly to determine packed cell volume (PCV), and parasite fecal egg count (FEC), respectively. The animals were divided into: dry, pregnant and lactating ewes, lambs and rams. Haemonchus was the predominant helminth genus (94.7%) during the whole year. There were up to 97% of success on the interpretation of FMC with 90 to 100% efficacy in the treatment decision. Among the 1356 evaluations, in only 40 (3%) were required deworming, bein...
Veterinary Parasitology, 2018
Experimental Parasitology, 2019
The blowfly Lucilia cuprina has great medico-sanitary and veterinary importance due to the abilit... more The blowfly Lucilia cuprina has great medico-sanitary and veterinary importance due to the ability of its larval form to develop in decaying organic matter, parasitizing vertebrates. Fly eradication is challenging and the essential oil (EO) of Tagetes minuta (TMEO) have been reported to have therapeutic properties. This study aimed to determine the activity of EO from the aerial parts of T. minuta against third instar larvae (L3) of L. cuprina. Groups of 20 L3 were placed on filter paper, which were impregnated with varying concentrations (0.19; 0.39; 0.79; 1.59; 2.38; 3.18; 4.77; and 6.36 µL/cm 2) of TMEO solubilized in acetone, ethanol or Tween 20. Histological tissue damage of TMEO was measured in L3 after 24, 48 and 96h of exposure. Dihydrotagetone (67.64%), trans-ocimene (16.23%), trans-tagetone (10.14%) and verbenone (2.98%) were obtained as major compounds of TMEO. Lethal concentrations of 50%, 24 and 48 h after TMEO exposure were 1.02 and 0.73 µL/cm 2 for acetone; 3.37 and 1.75 µL/cm 2 for ethanol; and 7.46 and 6.11 µL/cm 2 for Tween 20, respectively. TMEO had a significant L3 mortality of 96.6% in acetone, 48 h after contact. Cuticle abnormalities were observed, as well as the loss of digestive tract architecture and vacuolization in fat bodies. TMEO presented time and concentration-dependent effects against L. cuprina. As our study demonstrated a strong insecticide activity of TMEO, we consider that it could be developed into an ecofriendly product against L. cuprina.
Veterinary Parasitology, 2018
The aim of this study was to characterize the extracts and fractions of Persea americana Mill. (A... more The aim of this study was to characterize the extracts and fractions of Persea americana Mill. (Avocado) seeds and to determine the composition and the in vitro anthelmintic activity against third-stage larvae (L3) of Haemonchus contortus. The fresh (F) and dried (H) avocado seeds (PA) were subjected to extraction with hot water (W-PAF, W-PAH), ethanol (E-PAF, E-PAH) or methanol 70% (v/v), and partition with solvents of increasing polarity [nhexane (H-PAF, H-PAH), chloroform (C-PAF, C-PAH), ethyl acetate (Ea-PAF, Ea-PAH), and n-butanol (B-PAF, B-PAH)], yielding a total of 14 extracts/fractions. After considering the yield, water solubility, and the preliminary results of the larval migration test (LMT), the E-PAF, E-PAH, H-PAF, and H-PAH were selected for further experiments. E-PAH presented an efficiency concentration of 50% (EC 50) of 36 μg/mL on the LMT. E-PAH showed the greatest efficiency when its EC 50 was compared to the other fractions (E-PAF = 147 μg/mL; H-PAF = 801 μg/mL; H-PAH = 77 μg/mL). After that, the E-PAH was chemically characterized, considering its quantitative polyphenolic and flavonoid contents by colorimetric and chromatographic techniques. E-PAH presented 50, 38, and 24 mg/g of dry matter of total phenol, condensed tannins (CT), and flavonoid contents, respectively. Using high performance liquid chromatography (HPLC) analysis, E-PAH had shown to have epicatechin (4.7 μg/mL), rutin (2.8 μg/mL), and chlorogenic acid (1.4 μg/mL) as its main constituents besides quercetin. These isolated compounds were evaluated using the LMT in order to relate the composition to the anthelmintic activity observed for E-PAH. Quercetin (EC 50 = 7.8 μg/mL) and epicatechin (EC 50 = 10 μg/mL) presented a higher efficiency than rutin (EC 50 = 30 μg/mL). Chlorogenic acid was also tested with the LMT but did not present a significant efficiency. According to the results, the phenolic composition of E-PAH and the EC 50 values obtained for the isolated phenols, it can be suggested that, besides the CT content, the presence of epicatechin and rutin contributed to the larvicidal activity of E-PAH. In conclusion, avocado seeds may be used as a source of polyphenols with promising anthelmintic applications.
Data in Brief, 2018
Morphological biomarkers as the histopathological assessment and scanning electron microscopy can... more Morphological biomarkers as the histopathological assessment and scanning electron microscopy can be used to establish a diagnosis of structure damage and intoxication of target cells by new biopesticide candidate. In this sense, cuticle damage caused by active substances in larvae exposed to biopesticides can help to elucidate the mode action. Thus, insecticide activity analysis of essential oil of Curcuma longa leaves and its major compound α-phellandrene have proven to be a new biopesticide candidate against third instar larvae (L3) of the Australian blowfly Lucilia cuprina. In this way, groups of 20 L3 were placed on filter paper, impregnated with ranging concentrations (from 0.15 to 2.86 μL/cm 2) of C. longa leaves EO and (0.29-1.47 μL/cm 2) to Contents lists available at ScienceDirect
Journal of Essential Oil Research, 2018
Abstract Piper gaudichaudianum grows abundantly throughout the Brazilian Atlantic Forest. Essenti... more Abstract Piper gaudichaudianum grows abundantly throughout the Brazilian Atlantic Forest. Essential oil extracted from this species has been reported to have larvicidal properties. The aim of the study was to characterize the essential oil (EO) of P. gaudichaudianum and its insecticide activity on the third instar larvae (L3) of Lucilia cuprina under laboratory conditions. Groups of 20 L3 were placed on filter paper impregnated with increasing concentrations of 2.5–30% (v/v), equivalent to 0.39–4.77 μL/cm2, solubilized in ethanol or acetone. The toxicity was determined by L3 mortality after 6, 24 and 48 h after contact. P. gaudichaudianum EO was also characterized using CG/MS. Lethal concentrations of 50% (LC50) 24 and 48 h after EO exposure were found to be 3.69 and 2.19 when solubilized in ethanol and 9.14 and 6.05 μL/cm2 when solubilized in acetone, respectively. The major compounds were germacrene B, δ-cadinene, γ-elemene, (Z)-cariophyllene, α-copaene, (E)-cariophyllene, α-calacorene, α-humulene and (E)-nerolidol. The study demonstrated the significant biological activities of P. gaudichaudianum EO (PGEO) compounds against L. cuprina.
Veterinary Parasitology: Regional Studies and Reports, 2017
Equine cyathostomin parasites are ubiquitous in grazing horses and have been shown to cause sever... more Equine cyathostomin parasites are ubiquitous in grazing horses and have been shown to cause severe inflammatory disease in the large intestine of horses. Decades of intensive anthelmintic therapy have led to widespread anthelmintic resistance in cyathostomins across the world. In Cuba, no anthelmintic products are formulated and sold for equine usage and little is known about anthelmintic efficacy of ruminant and swine formulations used. A strongyle fecal egg count reduction test was used to assess the efficacy of a liquid formulation of ivermectin labelled for use in swine, ruminants and carnivores and a pelleted formulation of albendazole labelled for usage in ruminants. Nine farms in the province Camagüey were enrolled in the study comprising 149 horses in total. Albendazole efficacy was reduced on five farms and with the other four farms having no signs of reduced efficacy. Mean farm efficacies were ranging from 41.7% to 100% on the tested farms. Coprocultures found large strongyle larvae present on all farms, but all larvae identified post-treatment were cyathostomins. Ivermectin was found 100% efficacious on all studied farms. This study provided evidence of reduced albendazole efficacy in the study population. Further work is needed to evaluate whether these findings reflect true resistance or if they are due to pharmacokinetic or pharmacodynamic characteristics of the pelleted formulation tested here.
Research in veterinary science, Jan 25, 2017
Anthelmintic resistance is a serious problem for the control of equine gastrointestinal nematodes... more Anthelmintic resistance is a serious problem for the control of equine gastrointestinal nematodes. In the present survey, 173 third stage larvae of cyathostomins were investigated from three different locations for the presence of the resistant genotype at codon 167 of the beta-tubulin gene, as this is the most prevalent mutation. The larvae from the state of Parana (n=67), Sao Paulo (n=54) and Santa Catarina (n=52), showed 61.2; 31.5 and 38.5% of the heterozygous resistant genotype - TTC/TAC, respectively. An unpublished mutation at codon 172 that results in a serine (S) to threonine (T) substitution was found in 17.9% (12/67) of samples from Parana; and 13.0% (7/54) of samples from Sao Paulo. We have compared the molecular diagnostic with the fecal egg count data (R(2)=-0.79) from the same farms, and consider that the use of routine molecular diagnostic in individual larva may help to determine the population genetic distribution that is associated with drug failure.
Organic Agriculture, 2014
With the purpose to identify alternatives to the use of oil seed crops and cereals in broiler fee... more With the purpose to identify alternatives to the use of oil seed crops and cereals in broiler feeding, we interviewed 21 family farmers raising broilers in alternative systems located in three relevant sites for the poultry industry in Brazil. Two groups in the south (Parana and Rio Grande do Sul) were organized in cooperatives raising slow-growing broilers in freerange systems. The third group was linked to a broiler company in the state of Sao Paulo producing antibioticfree (AF) broilers in intensive systems. Individual assessments were performed through surveys with semi-structured questions. Nutrient supply was heavily dependent on maize and soy. Free-range broilers were normally raised with access to outdoor areas in permanent paddocks with very little vegetation available. In the three sites, the finishing period of broilers was the production stage with higher feed supplementation. In addition, farmers producing AF broilers highlighted subclinical coccidiosis as of high economic importance. Production of slow-growing broilers in free-range systems would benefit from local resources for the finishing period. Novel feeding strategies for broilers are suggested based on the farmers' report, agroecological site characteristics, and production systems.
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Papers by Marcelo Molento