Laboratoires Phodé (France)

AimThis study was conducted to test the ability of a carvacrol‐based formulation (Phodé, France) to decrease the C. jejuni caecal load in inoculated broiler chickens and to study the impact of the C. jejuni inoculation alone or combined with the product, on the caecal microbiota.Methods and ResultsOn day 1, chickens were either fed a control feed or the same diet supplemented with a carvacrol‐based product. On day 21, the carvacrol‐supplemented chickens and half of the non‐supplemented chickens were inoculated with C. jejuni (108 CFU). Quantitative PCR was used to quantify C. jejuni in chicken caecal samples and 16S rRNA gene sequencing was carried out at 25, 31 and 35 days of age. A significant decrease of 1.4 log of the C. jejuni caecal load was observed in 35‐day‐old chickens supplemented with the product, compared to the inoculated and unsupplemented group (p < 0.05). The inoculation with C. jejuni significantly increased the population richness, Shannon and Simpson diversity and altered beta‐diversity. Compared to the control group, the C. jejuni inoculation causes significant changes in the microbiota. The carvacrol‐based product associated with C. jejuni inoculation increased the diversity and strongly modified the structure of the microbial community. Functional analysis by 16S rRNA gene‐based predictions further revealed that the product up‐regulated the pathways involved in the antimicrobial synthesis, which could explain its shaping effect on the caecal microbiota.ConclusionsOur study confirmed the impairment of the caecal bacterial community after inoculation and demonstrated the ability of the product to reduce the C. jejuni load in chickens. Further investigations are needed to better understand the mode of action of this product to promote the installation of a beneficial microbiota to its host.Significance and Impact of the StudyResults suggested that this product could be promising to control C. jejuni contamination of broilers.

Phylogenetic studies on several groups of arthropods, such as Acari (mites) or Collembola (springtails), make wide use of chaetotaxy. Chaetotaxic characters, besides being morphological features (setal shape), often have a binary nature, that is presence vs. absence. A seta can be variable in a population, and one may attribute a presence probability to this seta. In fact, the presence probability should be defined for each instar. One might think that a variable seta corresponds to a polymorphism (e.g., two or more alleles in a population); in fact, setal variability should be regarded as the result of a propensity intrinsic to individuals, i.e., a potentiality being expressed at random among specimens. The phenomenon known as lateral inhibition explains how an early random fluctuation is at the root of the cell fate. Probabilistic organs are likely to originate from a similar phenomenon. A tridimensional species/instars/characters table (SIC table), containing setal presence probabilities, can be built up. Two kinds of analyses may be applied to such a table. In these analyses, the problem of homeotypic setae is emphasized. Related issues are the accuracy of using setal probabilities and the problem of reducing redundancy of information. A first process leads to a bidimensional table with characters in columns, and the species divided into their instars in rows. By using multidimensional statistics we can access ontogenetic trajectories, and in this way, ontogenetic comparisons can be achieved. The aim of the second process is to produce a species/characters table which can be used in a cladistic analysis.

In vitro cuticular deposition by larval epidermic material depends on hormonal conditions. Quantitative and qualitative variations are reported according to defined stimulations. Possible specific actions of each hormone are discussed.