Restoration of anticoccidial sensitivity to a commercial broiler chicken facility in Canada

Effects of dietary essential oil supplementation on growth performance, carcass yield, meat quality, and intestinal tight junctions of broilers with or without Eimeria challenge

The effects of dietary supplementation of essential oil on growth performance, carcass yield, meat quality, serum antioxidant capacity, and intestinal tight junctions of broilers with or without Eimeria challenge were investigated. A total of 576 one-day-old male broilers were randomly separated into 8 treatments (6 replication floor-pens per treatment, 12 broilers per pen) in a 4 × 2 factorial design. The 4 diets consisted of 1) a corn and soybean meal basal diet, 2) an anticoccidial diet (60 g nicarbazin and 60 g narasin per ton of feed), 3) an oregano oil diet (500 ppm oregano oil), and 4) a clove oil diet (500 ppm clove oil). On d 10, half chicks were challenged with 1 × 104 sporulated oocysts of E. tenella, E. acervulina, and E. maxima per chick, whereas the others were inoculated with an equal amount of dilution (0.5 mL). The Eimeria challenge induced a higher fecal oocyst output on d 18, a lower duodenum Occludin expression level on d 28, a lower serum catalase level, and a higher cook loss and protein loss in thigh muscle on d 42. The anticoccidial diet lowered fecal Eimeria output and increased d 1 to 42 BW gain as compared to the control diet. The clove oil treatment enhanced duodenum ZO-1 expression level in nonchallenged birds, increased BW gain from d 1 to 14 and breast yield on d 42. The oregano oil treatment enhanced ZO-1 expression of challenged birds, reduced feed intake from 15 to 28 d, and helped broilers gain more tender meat. For those Eimeria-challenged broilers, both clove and oregano oil treatments recovered drip loss in breast muscle. Our results suggested that Eimeria challenge in broiler early age could interrupt later serum antioxidant capacity and damage meat quality. The dietary supplementation of clove or oregano essential oils could improve broiler growth performance and partially relieve the coccidial damage in gut integrity and meat quality.

Meta-Analysis of the Use of Eimeria Lesion Scores and Oocyst Counts in Floor-Pen Studies

The success of treatments for, or prophylaxis of, coccidiosis with classical anticoccidial feed additives or alternative treatments can be measured with a variety of metrics. Three important metrics are body weight or body weight gain (BW or BWG), lesion scores (LS), and oocyst shedding (OS). A meta-analysis of floor-pen experiments was performed to determine if using LS and OS would lead to systematically different assessments compared to the use of BW at the end of the experiment, and to what degree changes in LS and OS are correlated with BW. We also investigated if there were days postinfection on which one could expect larger ratios between untreated control groups and treated groups for LS and OS as an aid to selecting sampling days. A total of 38 experiments from 37 articles in peer-reviewed journals were included. Data sets containing experiments that investigated LS or OS in addition to BW or BWG to assess anticoccidial feed additives or alternative treatment were tested for the effectiveness of the intervention either by univariate meta-analyses for each metric or by robust variance estimation multivariate meta-analysis combining BW with LS or BW with OS. The results did not show evidence that the inclusion of LS and OS in experimental designs to assess the effect of conventional and alternative feed additives with assumed anticoccidial activity systematically changed the conclusions drawn from an experiment, but there was no significant correlation between the LS and OS ratios of untreated and treated groups determined during the experiments with the ratios of the BW at the end of the experiment for each experiment. There was also no discernible relationship between LS or OS ratios and days postinfection.

PCR identification and prevalence of Eimeria species in commercial turkey flocks of the Midwestern United States

The present study used a PCR approach to characterize prevalence of coccidial species in fecal samples obtained from 40 individual Midwestern turkey flocks to characterize distribution of species in commercial flocks. Each sample was screened for 6 prominent Eimeria species using species-specific primers and was supplemented with a primary nested-PCR approach for amplification of mitochondrial cytochrome c oxidase subunit gene I where initial sample DNA concentrations were low. All samples were positive for at least one species of Eimeria, while most presented 2 (20/40) or 3 (14/40) species in total. Prevalence across farms was primarily dominated by E. meleagrimitis (97.50%), E. adenoeides (95%), and E. gallopavonis (40%). Of the samples positive for E. adenoeides and E. meleagrimitis, almost half (17/40) contained additional species. Data presented here offer insight into Eimeria species currently challenging the Midwestern US turkey industry and potential need to evaluate flocks for species prior to implementing vaccination programs.

Sensitivity of field isolates of Eimeria acervulina and E. maxima from three regions in Brazil to eight anticoccidial drugs

Rotation with different active ingredients is among the most effective and recommended strategies to preserve the efficacy of anticoccidial drugs and reduce the emergence of resistance. Tools such as anticoccidial sensitivity tests (ASTs) are ideally used to make rational rotation programs and bring benefits to production. The objective of this study was to evaluate the sensitivity of E. acervulina (EA) and E. maxima (EM) from 3 different regions in Brazil, by using four ASTs. Feces samples weighing 6 to 7 kg were collected in the regions of São Paulo, Paraná, and Minas Gerais. Prevalent oocysts from feces were filtered, identified, and quantified to conduct 2 ASTs with EA and 2 with EM. The same experimental design was used in every AST (4 replicates per treatment, with 6 birds each, for a total of 240 birds). Treatment groups were a nonchallenged and nonmedicated control group (T1), a challenged and nonmedicated control group (T2), and the other groups challenged and treated with the following compounds: lasalocid (90 ppm - T3), maduramycin (6 ppm - T4), decoquinate (30 ppm - T5), nicarbazin+semduramicin (66 ppm - T6), monensin (110 ppm - T7), salinomycin (66 ppm - T8), narasin+nicarbazin (100 ppm - T9), and nicarbazin (125 ppm - T10). At the end of each AST (20 d), the percent change (delta value) between the treated group (T3 to T10) and the control group (T2) was calculated for the following variables: body weight gain, feed conversion ratio, lesion score, and an indicator of percentage of optimal anticoccidial activity (POAA) that included T2. Different sensitivity levels of EA and EM isolates could be identified. As a whole, drugs from T5 and T3 groups showed higher delta values when compared to other compounds, whereas the lowest sensitivity levels of these isolates were observed in groups T4 and T7. Despite some limiting factors, ASTs can be a good tool for strategic selection of anticoccidial drugs in order to maintain efficacy and extend the lifespan of these molecules.