Effects of curcumin (diferuloylmethane) on Eimeria tenella sporozoites in vitro

Dietary Curcuma longa enhances resistance against Eimeria maxima and Eimeria tenella infections in chickens

The effects of dietary supplementation with an organic extract of Curcuma longa on systemic and local immune responses to experimental Eimeria maxima and Eimeria tenella infections were evaluated in commercial broiler chickens. Dietary supplementation with C. longa enhanced coccidiosis resistance as demonstrated by increased BW gains, reduced fecal oocyst shedding, and decreased gut lesions compared with infected birds fed a nonsupplemented control diet. The chickens fed C. longa-supplemented diet showed enhanced systemic humoral immunity, as assessed by greater levels of serum antibodies to an Eimeria microneme protein, MIC2, and enhanced cellular immunity, as measured by concanavalin A-induced spleen cell proliferation, compared with controls. At the intestinal level, genome-wide gene expression profiling by microarray hybridization identified 601 differentially expressed transcripts (287 upregulated, 314 downregulated) in gut lymphocytes of C. longa-fed chickens compared with nonsupplemented controls. Based on the known functions of the corresponding mammalian genes, the C. longa-induced intestinal transcriptome was mostly associated with genes mediating anti-inflammatory effects. Taken together, these results suggest that dietary C. longa could be used to attenuate Eimeria-induced, inflammation-mediated gut damage in commercial poultry production.

In vitro and in vivo screening of anthelmintic activity of ginger and curcumin on Ascaridia galli

Intestinal helmintic infection, continue to be a cause of major concern in several parts of the world, particularly in the developing nations. The use of plant extracts to control poultry helminths is increasing in different rearing systems. The anthelmintic activity of ginger and curcumin was studied on the nematode Ascaridia galli. In vitro and in vivo studies were allocated. Live parasites for in vitro studies were collected from the intestine of naturally infected chickens. Some living worms were incubated at 37 °C in media containing ginger at three concentration levels (25, 50, and 100 mg/ml), and others were incubated in media containing curcumin at the same concentration levels. Another living worm group was incubated in media containing albendazole at a dose of 7.5 mg/ml. The extracts' efficacy was exhibited in a concentration-time-dependent manner mainly at 100 mg/ml and after 48 h. The in vivo study takes place on experimentally infected chickens. Group of infected chickens was treated with ginger extract at dose of 100 mg, another group was treated with curcumin extract at dose of 100 mg, and a third group was treated with albendazole at dose of 7.5 mg. In vivo study of ginger and curcumin recorded lower mortality rates than the in vitro study. It is concluded that ginger and curcumin extracts have potential anthelmintic properties against A. galli. Ginger in all concentrations used exhibited a higher death rate observed than curcumin. Their wormicidal effect is concentration-time dependent.

Anticoccidial effects of a novel triazine nitromezuril in broiler chickens

The anticoccidial efficacy of 2-(3-methyl-4-(4-nitrophenoxy)phenyl)-1,2,4-triazine-3,5(2H,4H)-dione (nitromezuril, NZL), a novel triazine compound, was evaluated in three different studies under experimental conditions. The anticoccidial efficacy was chiefly evaluated using the anticoccidial index (ACI). The resistance level was determined by calculating ACI, percentage optimum anticoccidial activity (POAA), reduction in lesion scores (RLS) and relative oocyst production (ROP). In the dose determination study (study A), NZL was added to the diet at doses of 1, 2, 3, 4, 5 and 6 mg/kg to test its efficacy against coccidiosis caused by Eimeria tenella. Groups treated with NZL 1mg/kg feed could observe the faecal dropping scores and caecal lesions. ACIs of NZL-treated groups reached 179-199. In the study on the anticoccidial efficacy of 3mg/kg NZL in the diet (study B), only a few faecal oocysts and slight lesions were observed. NZL significantly promoted weight gain (WG) and reduced lesion scores (LS) compared to controls receiving diclazuril (DZL) (P<0.05). ACIs of NZL-treated groups were 193, 192, 191 and 163 for E. tenella, Eimeria necatrix, Eimeria acervulina and Eimeria maxima, respectively, whereas those of DZL-treated groups were 185, 176, 176 and 148. In the cross-drug resistance study (study C), ACIs of NZL and toltrazuril (TZL)-treated groups ranged from 188 to 204, which were significantly higher than those of DZL-treated groups (P<0.05). NZL- and TZL-treated groups were sensitive to experimentally induced DZL-resistant E. tenella, whereas DZL-treated groups showed complete resistance. No cross-resistance was observed between DZL and NZL or TZL. Based on the abovementioned studies, it was concluded that diets containing 3 mg/kg NZL had an excellent efficacy in preventing coccidiosis in broiler chickens. The activity of 3mg/kg NZL in the diet was equal or superior to that of 1 mg/kg DZL. These results are of great significance for the future applications of NZL; however, its actual mechanism of action remains unknown. NZL is a potential novel anticoccidial agent suitable for further development.

A novel serine/threonine protein phosphatase type 5 from second-generation merozoite of Eimeria tenella is associated with diclazuril-induced apoptosis

Screening the anticoccidial drug targets is very important for developing novel drugs and revealing the molecular basis of drug resistance in coccidia. Due to high effectivity and safety, diclazuril was used widely in the poultry industry. To assess the roles of the serine/threonine protein phosphatase type 5 of second-generation merozoites in Eimeria tenella (EtPP5) in the anticoccidial activity of diclazuril against chicken coccidiosis, EtPP5 was cloned using reverse transcriptase polymerase chain reaction and rapid amplification of cDNA ends. Ultrastructural changes in second-generation merozoites and mRNA expression level of EtPP5 were monitored by transmission electron microscopy (TEM) and quantitative real-time PCR, respectively. The results showed that the full length of the cloned EtPP5 cDNA (2,495 bp) encompassed a 1,647-bp open reading frame encoding a polypeptide of 548 residues with an estimated molecular mass of 60.82 kDa and a theoretical isoelectric point of 5.89. Molecular analysis of EtPP5 reveals the presence of a C-terminal phosphatase domain and an extended N-terminal tetratricopeptide repeat motif, a typical feature of protein phosphatases. The cDNA sequence has been submitted to the GenBank database with accession number JX987508. EtPP5 shared 89% homology with the published sequence of a PP5 ortholog of Toxoplasma gondii at the amino acid level (GenBank XP_002364442.1). TEM observed that diclazuril induced ultrastructural changes in second-generation merozoites. Quantitative real-time PCR analysis showed that compared with the control group, the level of EtPP5 mRNA expression was significantly downregulated by 51.4% by diclazuril treatment. The high similarity of EtPP5 to previously described PP5 of other organisms, as well as its downregulated expression and connection with apoptosis in the second-generation merozoites induced by diclazuril, suggests that it could act an important role in understanding the signaling mechanism underlining the diclazuril-induced merozoites apoptosis.

In vitro inhibition of Eimeria tenella invasion of epithelial cells by phytochemicals

Resistance to coccidiostats and possible future restrictions on their use raise the need for alternative methods of reducing coccidiosis in poultry. The aim of this study was to evaluate the effect of selected phytochemicals on Eimeria tenella sporozoite invasion in vitro. Four phytochemicals were selected on the basis that they reduce the virulence of Eimeria spp. and/or provide immune modulatory benefits to host cells: betaine, carvacrol, curcumin and Echinacea purpurea extract (EP). Madin-Darby bovine kidney (MDBK) cells were covered by medium containing phytochemicals at the highest concentration which was non-toxic to the cells. Salinomycin 50 μg/ml was positive control; negative control was medium only. E. tenella (Houghton strain) sporozoites were added to wells and after incubation for 2, 4 or 20 h at 37°C, cells were fixed and stained with hematoxylin-eosin. Ten evenly spaced fields per well were photographed and the percentage of cells invaded by sporozoites was calculated and normalized to the control. At 2h, carvacrol, curcumin and EP showed a significantly lower percentage of sporozoite invasion than the untreated control; in contrast, betaine treatment represented a significantly higher invasion percentage. Combining carvacrol with EP inhibited E. tenella invasion more effectively than applying the compounds individually, but the further addition of curcumin did not reduce invasion further. In conclusion, this study shows that invasion of MDBK epithelial cells by E. tenella sporozoites is inhibited in the presence of carvacrol, curcumin, or EP and enhanced by betaine. There may be potential for developing these phytochemicals as anti-coccidial feed or water additives for poultry.

Anticoccidial effect of halofuginone hydrobromide against Eimeria tenella with associated histology

Halofuginone (stenorol) has been used as an effective anticoccidial reagent for decades but very little is known about its mode of action. In this study, chickens were inoculated with Eimeria tenella oocysts on 14-day-old and medicated with halofuginone at days 0, 1, 2, 3, 4, 5 and 6 post inoculations (groups 0, 1, 2, 3, 4, 5 and 6, respectively). Chickens in group 7 were taken as challenge-unmedicated control and in group 8 unchallenged-unmedicated control. The survival rate, body weight gains (BWG), oocysts production, cecal scores, bloody diarrhea and histological examinations were analyzed to evaluate the anticoccidial efficacy of halofuginone and to initially elucidate its mechanisms. Results showed that halofuginone which acted as a coccidiostatic can significantly enhance the BWG, and decrease both the oocyst shedding and cecal destruction caused by E. tenella infection. The histological slide examination noted that halofuginone was effective when provided 0-2 days post inoculation but only partially effective when applied 3-7 days post infection. The second-generation schizonts treated with halofuginone appeared vacuolated and degenerated. It is concluded that halofuginone can inhibit the parasite's invasion of host cecal hypothetical cell at the early stages of life cycle and later disturb the parasite's development by vacuolation of the schizonts. The resulting abnormal schizonts could not divide into schizoites and were eventually eliminated by the host's immune response.