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La grande majorité des populations humaines réside dans les villes en 2018 et cette tendance s’intensifie. Pour répondre aux enjeux de bien-être et santé de ces populations, des projets d’alimentation durable se développent et concernent en particulier les productions de proximité, la reconnexion des consommateurs avec la production des denrées, ainsi que les considérations environnementales. C’est ainsi que des élevages non commerciaux de poules apparaissent en ville, souvent encouragés par les élus ou agences gouvernementales pour réduire aussi les quantités de déchets organiques des ménages. Afin d’inscrire dans une démarche d’amélioration continue ces nouvelles pratiques urbaines qui se démarquent des élevages traditionnels, il convient de les décrire (typologies, pratiques et règlements associés aux poulaillers urbains), puis de cerner les opportunités et les risques environnement-santé liés à ces élevages. C’est l’objectif de cette publication co-écrite par des chercheurs et associations, qui aborde de façon interdisciplinaire (environnement-santé, société, risques et réglementation) les diverses facettes des poulaillers urbains, pour éclairer les différents acteurs concernés et souligner également les lacunes de connaissances à combler. In 2018, the majority of human populations reside in cities and this trend is intensifying. To promote both the well-being and health of these urban populations, sustainable food projects are developing and concern in particular local production, the reconnection of consumers with food production, as well as environmental considerations. Thus, non-commercial urban poultry houses appear, often encouraged by official agencies for environment in order to reduce the amount of organic waste in households. With the aim of continuous improvement, it’s crucial to increase the knowledge about these new urban practices : typologies, practices and regulations associated, then to identify the opportunities and the potential environment-health risks related to these family urban poultry houses. This is the aim of this publication, co-written by researchers and associations, which tackles the various facets of urban poultry houses in an interdisciplinary way (environment-health, society, risks and regulation), in order to enlighten the various actors concerned and also to highlight knowledge gaps to be filled.

The effects of chronic gamma radiation at dose rates ranging from 0.058 mGy d-1 on growth rate calculated during the early stationary phase were studied. A stimulatory effect occurred for all doses and for all phases of the cells selected for use in the inoculation of the medium. During the same period, the rate of nucleic acid synthesis was increased in irradiated cultures compared to control cultures. The stimulating effect always occurred in cultures irradiated from the inoculation to the eighteenth day only. This result led us to conclude that the stimulation mechanism depended upon the events occurring at the end of the exponential phase in the deceleration period. Studies on cell metabolism showed that cells presented features of photooxidative stress in this period. Increases in superoxide dismutase, glutathione reductase and glucose-6-phosphate dehydrogenase were observed in irradiated cultures. It was assumed that irradiation at very low doses could help cells to better defend against photooxidative stress by increasing oxidants that activate the glucose metabolism and C5-sugars production and nucleic acid synthesis.

Previous results from this laboratory have shown that very low chronic doses of gamma radiation can stimulate proliferation of the Cyanobacterium Synechococcus lividus. This modification of cell proliferation occurred during the first doubling. In this paper, we have compared the metabolism of cells cultivated in a normal environment or under chronic irradiation. Incubation of the cells in a new medium induced a high superoxide dismutase (EC 1.15.1.1, SOD) activity at the 18th hour and a degradation of phycocyanin, thus demonstrating that cells were submitted to a photooxidative stress. This increase in superoxide dismutase activity was followed by concomittant peaks of glutathione reductase (EC 1.6.4.2, GR) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49, G6P-DH) at the 24th hour. Irradiated cultures at a dose of 53.5 mGray/year show an earlier and higher peak of SOD, GR, and G6P-DH. In a second stage, cultures showed an earlier onset of photosynthesis under irradiation, as evidenced by an increase in pigment content and an enhancement of glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.13, GAP-DH). These results show that the radiostimulation is related to the activation of enzymes protecting against peroxides that were induced under oxidative circumstances and to the activation of a glucose catabolism via the oxidative pentose phosphate pathway.