The aim of the present work was, after a coccidiosis outbreak in a farm rearing red-legged partridges (Alectoris rufa) in Brittany (France), to identify the Eimeria species and describe gross lesions induced by three of them (Eimeria kofoidi, Eimeria caucasica and Eimeria legionensis) after experimental infection. E. kofoidi oocysts measured 19.3 µm × 16.3 µm on average; neither micropyle nor oocyst residuum were present, but one, two or more small polar granules were visible. After inoculation of 300,000 oocysts per partridge, severe gross lesions were observed in the duodenum and jejunum, characterized by thickened oedematous mucosa and lumen filled with thick mucus, gas and sometimes false-membrane due to sloughed epithelium. E. caucasica oocysts were on average 29.8 µm × 19.5 µm in size; no oocyst residuum was observed, but a large granule was well visible. E. caucasica also invaded both the duodenum and jejunum, causing haemorrhagic points on the serosal surface, as well as mucoid duodenitis and catarrhal enteritis when 30,000 oocysts were inoculated per bird. E. legionensis oocysts measured 22.6 µm × 14.9 µm on average; they presented a clear micropyle beneath which one or two granulations were present. E. legionensis mainly invaded the caeca; low mortality was observed at the dosage of 200,000 oocysts per bird. Caecal walls were thickened and caseous material was condensed into off-white cheesy cores. For each species, oocyst shedding started 5 days post inoculation, peaked at 9, 8 and 6 days post inoculation for E. kofoidi, E. caucasica and E. legionensis, respectively, then decreased and persisted until 15 days post inoculation (end of examinations).

A randomized controlled trial (RCT) was carried to evaluate the effect of a feed additive on Campylobacter contamination of broilers reared in commercial conditions. Twenty-four broiler flocks naturally contaminated with Campylobacter were enrolled in the RCT: 12 were assigned to a control group (C) fed with a conventional finishing feed from 4 weeks of age to slaughter (around 35 days), and the other group of 12 flocks (S) was fed with a finishing feed supplemented with 250 ppm of a patented feed additive (an ion-exchanged clay compound) previously proven to reduce Campylobacter contamination in broiler caeca under experimental conditions. Enumeration of Campylobacter colonies in caeca (8 per flock) was carried out following ISO standards before feed distribution and at slaughter. Before treatment, the caecal Campylobacter load tended to be lower in C flocks (7.1 ± 1.9 log CFU/g, CI [6.6-7.5]) than in S flocks (7.7 ± 1.0 log UFC/g, CI [7.5-7.9]) (p = .05). At slaughter, the bacterial load was similar in the S (7.7 ± 1.0 log CFU/g, CI [7.5-7.9]) and C groups (7.5 ± 1.2 log CFU/g, CI [7.2-7.8]) (p = .73). Therefore, the feed additive had no significant effect on the caecal Campylobacter load at slaughter under the tested conditions. The logistical constraints inherent in field trials and the natural variability of Campylobacter contamination in naturally infected broiler flocks make it difficult to reproduce experimental results in in situ farm conditions. RCT testing of an intervention strategy in commercial situation is therefore a key step in evaluating pre-harvest interventions against food-borne pathogens.

No abstract

After ban of antibiotics growth promoters (AGP) in Europe in 2006, use of non-medicated gut microbiota regulators as feed additives has dramatically increased. This study aimed at describing the effects of a copper-exchanged zeolite on broiler growth performance, small intestine morphology and microbiota composition. Illumina Sequencing of the V3-V4 region of the 16S rRNA gene was employed to study the small intestine microbiota. This microbiota with copper-exchanged zeolite treated-chickens was significantly less diverse with an almost exclusive presence of Lactobacillus johnsonii and Lactobacillus reuteri. These Lactobacilli are correlated with increased diameter, length and weight of the three segments of the small intestine and decreased viscosity of the intestinal content, suggesting probiotic action. The tested copper-exchanged zeolite would act as a prebiotic, selecting a "favorable" flora for the healthy broilers development.