Environmental enrichment during laying influences offspring’s phenotype in the Japanese quail
Résumé
Animal welfare is strongly influenced by characteristics of the animals' environment. Thus, enrichment of Mammals' and Birds' environments at early age modulates their behavioural development and can increase their ability to cope with their milieu, consequently improving the animals' welfare. However, individual behavioural development is strongly affected prenatally by maternal living conditions. Many authors consider these prenatal maternal effects to be prenatal adaptive mechanisms preparing offspring for their postnatal environment. In this context, our study investigated the effects of environmental enrichment (via foraging and structural enrichments) of laying Japanese quail females’ living conditions on their offspring’s general development. For that, 10 laying quail were kept in enriched cages (EC females) for 5 weeks and characteristics of their eggs and chicks were compared to those of 10 females housed in standard cage (SC females). After the treatment, EC females were heavier than SC females and produced eggs containing proportionally more yolk and less albumen than those of SC females. However, levels of egg hormonal contents (testosterone, androstenedione, progesterone) did not differ significantly between the two groups. Chicks of EC females (EC chicks) were globally heavier than chicks of SC females (SC chicks) from hatching to 5 weeks old and their sexual development was more precocious than that of SC chicks. Moreover, emotional reactivity of EC chicks, in behavioural tests, was lower and their social motivation was higher than that of SC chicks. So, our study shows that enrichment of laying females’ environment modulates their offspring’s morphological and behavioural development, probably in relation to characteristics of the eggs. Controlling prenatal maternal effects could be a way to improve animal welfare over several generations.