Anthelmintic resistance in hair sheep farms in a sub-humid tropical climate, in the Huasteca Potosina, Mexico

Oxalis tetraphylla (Class: Magnoliopsidae) Possess Flavonoid Phytoconstituents with Nematocidal Activity against Haemonchus contortus

The nematocidal activity of an Oxalis tetraphylla hydroalcoholic extract against the nematode Haemonchus contortus (Hc) was assessed in vitro and the major compounds associated with nematocidal activity were identified. One hydroalcoholic extract was obtained from O. tetraphylla stems and leaves (Ot HE-SLE). The in vitro lethal concentrations (LC50 and LC90) against both eggs and exsheathed Hc infective larvae (L3) were assessed. Ot HE-SLE showed a potent ovicidal activity (LC50 = 0.213 mg/mL; LC90 = 0.71 mg/mL) and larvicidal effect (LC50 = 28.01 mg/mL; LC90 = 69.3 mg/mL). Later on, the extract was bipartitioned to obtain an ethyl acetate phase (EtOAc-Ph) and an aqueous phase (Aq-Ph). Both phases were assessed against Hc eggs at 0.25 and 1.0 mg/mL concentrations. The results with EtOAc-Ph showed 93.6% ovicidal activity, while 96.6% was recorded with Aq-Ph at 48 h post-confrontation (PC). In the case of larvicidal activity, both phases were assessed at 28 mg/mL; Aq-Ph showed >80% larvicidal activity 24 and 72 h PC, while EtOAc-Ph did not show important activity. HPLC analysis showed the presence of coumaric acid and flavonols. Flavonol compounds were the major compounds and were associated with the nematocidal activity. Additionally, the Aq-Ph that showed the highest activity was purified, and the fraction F3 showed the highest nematocidal activity.

Poloxamer 407/188 Binary Thermosensitive Gel as a Moxidectin Delivery System: In Vitro Release and In Vivo Evaluation

Moxidectin (MXD) is an antiparasitic drug used extensively in veterinary clinics. In this study, to develop a new formulation of MXD, a thermosensitive gel of MXD (MXD-TG) was prepared based on poloxamer 407/188. Furthermore, the gelation temperature, the stability, in vitro release kinetics and in vivo pharmacokinetics of MXD-TG were evaluated. The results showed that the gelation temperature was approximately 27 °C. MXD-TG was physically stable and can be released continuously for more than 96 h in vitro. The Korsmeyer−Peppas model provided the best fit to the release kinetics, and the release mechanism followed a diffusive erosion style. MXD-TG was released persistently for over 70 days in sheep. Part of pharmacokinetic parameters had a difference in female and male sheep (p < 0.05). It was concluded that MXD-TG had a good stability, and its release followed the characteristics of a diffusive erosion style in vitro and a sustained release pattern in vivo.

Bacterial communities in the gastrointestinal tract segments of helminth-resistant and helminth-susceptible sheep

Background

Helminth parasitism is a world-wide problem in livestock industries, with major impacts on health, welfare and productivity. The role of the gut microbiota in host-helminth interactions in ruminants has been extensively examined and the present study added to this body of knowledge by assessing the effects of resistance and susceptibility to helminth infection in the gastro-intestinal tract (GIT). Australian Sheep Breeding Values (ASBVs) for faecal egg count (FEC) were used to select the 10 highly helminth-susceptible (High-FEC) and 10 highly helminth-resistant (Low-FEC) sheep. FEC status was confirmed during the experiment. Using samples from the faeces and the lumen of the rumen, abomasum, duodenum, jejunum, ileum, caecum, and colon, DNA was extracted and used for 16 rRNA gene amplicon sequencing.

Results

The most frequent genera identified along the GIT were Eubacterium, Oscillibacter, and Ruminococcus. Intersectoral-specialization zones were identified along the GIT, with the duodenum displaying major differences between the High-FEC and Low-FEC animals in values for alpha and beta diversity. After taking all samples into account and adjusting for GIT segment, the High-FEC and Low-FEC sheep differed significantly for four genera Butyrivibrio, Mycoplasma, Lachnoclostridium and Succiniclasticum. In the duodenum, the abundances of Aminipila, Lachnoclostridium and Mogibacterium differed significantly between the High-FEC and Low-FEC sheep. In the ileum, on the other hand, the genus Mycoplasma was significantly depleted in the Low-FEC group.

Conclusions

The gastro-intestinal microbial profile varies widely between helminth-resistant and helminth-susceptible sheep. Each GIT section appears to support a particular bacterial composition leading to inter-sectoral differences among the various microbial communities. The microbial populations were most rich and diverse in the duodenum of helminth-resistant sheep, comprising bacterial genera that generally ferment carbohydrates. This observation suggests that helminth-resistant sheep can reorganize the duodenal microbiome taxa which may restrict the development of parasites.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42523-022-00172-1.

Multiple Anthelmintic Resistance at a Goat Farm in Slovakia

Cases of parasite resistance to the main classes of anthelmintics are increasingly reported from small ruminants at farms in Europe. We visited a goat farm in Slovakia in November 2019 with suspected parasite problems that reduced productivity and performed an in vivo faecal egg count reduction test (FECRT) and an in vitro larval development test (LDT) for all three main classes of anthelmintics. The lowest efficacy (60 %) detected by FECRT was for ivermectin (IVM). Benzimidazole (BZ) efficacy ranged between 80.3 and 86.5 %, and levamisole (LEV) efficacy was 94 %. The results from the in vivo FECRT test were confirmed by the in vitro LDT. Minimum inhibitory concentration (MIC) 173.6 ng/ml for IVM several times exceeded the recommended threshold of 21.6 ng/ml. Mean LD₅₀ for BZ was equal to the threshold concentration, but the other threshold criteria indicated a low level of resistance in the population. The LDT did not indicate the presence of resistance only for LEV. The MIC 1.0 μg/ml for LEV was evaluated as susceptible with respect to species composition. Teladorsagia was the dominant genus after treatment with BZ, IVM, and LEV. Haemonchus contortus was identifi ed after treatment with BZ and LEV.

Assessment of Gastrointestinal Parasites and Productive Parameters on Sheep Fed on a Ration Supplemented with Guazuma ulmifolia Leaves in Southern Mexico

Simple Summary

Gastrointestinal (GI) parasite infections represent a serious problem in small ruminant production. This issue is currently potentiated by anthelmintic resistance. Thus, the need for more sustainable control alternatives has increased during recent decades. The use of bioactive forages with condensed tannins (CTs) has shown encouraging results. The local Mexican plant Guazuma ulmifolia is cited in ethnoveterinary studies and naturally selected by sheep (Pelibuey breed). G. ulmifolia contains a certain amount of CTs. Therefore, this study aimed at evaluating the impact of G. ulmifolia in sheep diet on animal performance and GI parasites eggs/oocysts excretion. Twenty-two sheep were randomly distributed into two groups: a control group without G. ulmifolia and a test group receiving a diet which contained G. ulmifolia fresh foliage at 30% of the total diet dry matter. For 30 days, weight, body condition, and GI parasite load were assessed. The results showed no significant anthelmintic and anticoccidial effects (p > 0.05) as well as inconsistent impact on live weight during the 30-days experiment. Nevertheless, considering the bromatological analysis of G. ulmifolia, its use as a diet supplement to adjust protein and calcium deficits of poor-quality forage is justified.

Abstract

This study aimed at evaluating the impact of a diet supplemented with Guazuma ulmifolia leaves on the productive performance and gastrointestinal parasites (GI) eggs/oocysts shedding of sheep (Pelibuey breed). Twenty-two non-lactating ewes were used. They were randomly allocated to two similar groups in terms of age, weight, body condition score (BCS), and GI parasites status. For 30 days, while the control group (G0) was given basic forage hay of Cynodon nlemfuensis, the test group (G1) received a blend of G. ulmifolia fresh foliage and C. nlemfuensis hay (respectively 30 and 70% of the diet on a DM basis). Animals were housed in separate covered pens. Quantitative coprological analysis was performed. Weight and BCS were evaluated. The daily feed amounts given and refused were measured in order to assess nutrient components intake (minerals, energy, and nitrogen). The results showed no significant differences between G1 and G0 regarding the anthelmintic and anticoccidial effects (p = 0.57, p = 0.91, respectively). Similarly, no significant overall impact on weight and BCS during the experiment (p = 0.77, p = 0.32, respectively) was observed. Nevertheless, concerning the bromatological analysis of G. ulmifolia, its use as a diet supplement to address protein and mineral deficits due to a poor-quality diet is fully justified.