Situation sanitaire des bovins des sous-systemes agropastoraux du riz et du mil pendant la saison des pluies. Resultat d'enquete parasitologique

Compte rendu des resultats de l'enquete parasitologique effectuee en saison humide chez les bovins des sous-systemes agropastoraux du riz et du mil de la zone de Niono, Mali, en vue de determiner la situation du parasitisme et d'evaluer son incidence sur l'etat sanitaire des troupeaux, avec indication d'une nette augmentation des taux d'infestation par rapport a la saison seche, avec proposition sur le besoin d'attention sur la fasciolose dans le sous-systeme riz

Effect of antibiotic withdrawal in feed on chicken gut microbial dynamics, immunity, growth performance and prevalence of foodborne pathogens

<div><p>Development of antibiotic resistance in foodborne pathogens, <i>Salmonella</i> spp. and <i>Campylobacter</i>, is a public health concern. Public demand to reduce the use of sub-therapeutic antibiotic growth promoters (AGP) in poultry feeding has resulted in greater adoption of antibiotic-free poultry production systems. There is a need to understand the effects of AGP removal from poultry feed on gut microbiota and its impact on prevalence of foodborne pathogens. The effect of antibiotic withdrawal from poultry feed on gut microbial community, host performance and immunity, and prevalence of <i>Salmonella</i> and <i>Campylobacter</i> was evaluated. Birds were raised on three phase diets (starter [d0-22], grower [d23-35] and finisher [d36-42]) with and without bacitracin dimethyl salicyclate (BMD). At early growth stage, bird performance was improved (P ≤ 0.05) with BMD treatment, whereas performance was better (P ≤ 0.05) in control group (no BMD in the feed) at the time of commercial processing. Acetate and butyrate production was affected (P ≤ 0.05) by age, whereas propionate production was affected (P ≤ 0.05) by both the treatment and age. The bacterial communities in the cecum were more diverse (P ≤ 0.001) and rich compared to the ileal communities, and they shifted in parallel to one another as the chicks matured. Differences in diversity and species richness were not observed (P > 0.05) between the BMD-fed and control groups. Comparing all ages, treatments and diets, the composition of cecal and ileal bacterial communities was different (P ≤ 0.001). Inclusion of BMD in the feed did not affect the bacterial phyla. However, predictable shift in the ileal and cecal bacterial population at lower taxonomic level was observed in control vs BMD-fed group. Cytokines gene expression (IL-10, IL-4, IFN-γ, beta-defensin, and TLR-4) was affected (P≤ 0.05) in the BMD-fed group at early stages of growth. The prevalence of foodborne pathogens, <i>Campylobacter</i> spp. and <i>Salmonella</i> spp. showed higher abundance in the ilea of BMD-fed chicks compared to control group. Overall, this study provided insight of the impact of AGP supplementation in the feed on gut microbial modulations, bird performance, host immunity and pathogen prevalence. This information can assist in designing alternative strategies to replace antibiotics in modern poultry production and for food safety.</p></div

Prevalence of food borne pathogens in cecum, ileum, litter and feed collected at different time points (d0, 7, 14, 22, 35, 42) from BMD-free and BMD supplemented groups.

<p>(A) Prevalence (in %) of <i>Salmonella</i> and (B) Prevalence (in %) of <i>Campylobacter</i>.</p

Volatile acid production in the cecum in BMD-fed and no BMD-fed group birds at different ages.

<p>Volatile acid production in the cecum in BMD-fed and no BMD-fed group birds at different ages.</p

Nutrient composition of the basal starter, grower and finisher diets.

<p>Nutrient composition of the basal starter, grower and finisher diets.</p

Effect of antibiotic withdrawal in feed on chicken gut microbial dynamics, immunity, growth performance and prevalence of foodborne pathogens - Fig 8

<p><b>Change in cytokine gene expression (A) β-defensin (B) TLR-4 (C) IL-10 (D) IL-4 and (E) IFN-α in the ilea.</b> Values are represented as means ± standard error of mean, where n = 4.</p

Real-time quantitative RT-PCR primers for the chicken pro and anti-inflammatory cytokines.

<p>Real-time quantitative RT-PCR primers for the chicken pro and anti-inflammatory cytokines.</p

Permutational ANOVA results partitioning effect of bird age, treatments and diet on microbial community composition of the cecum and ileum as calculated at a 97% cutoff as described in the text.

<p>Permutational ANOVA results partitioning effect of bird age, treatments and diet on microbial community composition of the cecum and ileum as calculated at a 97% cutoff as described in the text.</p

Heatmap of taxonomic groups present in the ileum of birds fed on BMD-diet and BMD-free diet (control group) across all ages (d0, 7, 14, 22, 35 and 42).

<p>The sample numbers (n = 6 for each time point) in red are of control diet and blue are of BMD diet.</p