Seasonal Survey of Contaminants (Cd and Hg) and Micronutrients (Cu and Zn) in Edible Tissues of Cephalopods from Tunisia: Assessment of Risk and Nutritional Benefits

International audienceConcentrations of cadmium (Cd), copper (Cu), mercury (Hg) and zinc (Zn) were determined by atomic absorption spectrophotometry in the muscle tissues (arms and mantle) of three commercial cephalopods (Loligo vulgaris, Octopus vulgaris and Sepia officinalis) caught in three different Tunisian coastal regions. The highest concentrations found correspond to the essential elements Cu and Zn. Octopuses and cuttlefish showed the highest levels of those elements while squid presented with significantly higher values of Hg in both muscular tissues. This may be related to different feeding behavior and detoxification processes among benthic and pelagic cephalopods. Variation of element concentrations between seasons was different between species and seemed to be mostly dependent on the sampling site. From a public health standpoint, average concentrations of Cd, Cu, Hg and Zn measured in edible tissues of cephalopods from this study did not reveal, in general, any risk for consumers. The estimated Target Hazard Quotients (THQs) for Cd and Hg for consumers of the selected species were below 1 and within the safety range for human health. Moreover, their consumption could provide in an important contribution to the daily dietary intake of Cu for the Tunisian population, especially regarding the consumption of octopus and cuttlefish muscles

First insights into the microbiome of Tunisian Hyalomma ticks gained through next-generation sequencing with a special focus on H. scupense.

Ticks are one of the most important vectors of several pathogens affecting humans and animals. In addition to pathogens, ticks carry diverse microbiota of symbiotic and commensal microorganisms. In this study, we have investigated the first Tunisian insight into the microbial composition of the most dominant Hyalomma species infesting Tunisian cattle and explored the relative contribution of tick sex, life stage, and species to the diversity, richness and bacterial species of tick microbiome. In this regard, next generation sequencing for the 16S rRNA (V3-V4 region) of tick bacterial microbiota and metagenomic analysis were established. The analysis of the bacterial diversity reveals that H. marginatum and H. excavatum have greater diversity than H. scupense. Furthermore, microbial diversity and composition vary according to the tick's life stage and sex in the specific case of H. scupense. The endosymbionts Francisella, Midichloria mitochondrii, and Rickettsia were shown to be the most prevalent in Hyalomma spp. Rickettsia, Francisella, Ehrlichia, and Erwinia are the most common zoonotic bacteria found in Hyalomma ticks. Accordingly, Hyalomma ticks could represent potential vectors for these zoonotic bacterial agents