Publication: Composition and evolution of the gut microbiota of growing puppies is impacted by their birth weight
Présentation
Low birth weight puppies present an increased risk of neonatal mortality, morbidity, and some long-term health issues. Yet it has not been investigated if those alterations could be linked to the gut microbiota composition and evolution. 57 puppies were weighed at birth and rectal swabs were performed at 5 time points from birth to 28 days of age. Puppies were grouped into three groups based on their birth weight: low birth weight (LBW), normal birth weight (NBW) and high birth weight (HBW). 16S rRNA gene sequencing was used to highlight differences in the fecal microbiota. During the first three weeks, the relative abundance of facultative anaerobic bacteria such as E. coli, C. perfringens and Tyzzerella was higher in LBW feces, but they catch back with the other groups afterwards. HBW puppies showed higher abundances of Faecalibacterium and Bacteroides during the neonatal period, suggesting an earlier maturation of their microbiota. The results of this study suggest that birth weight impact the initial establishment of the gut microbiota in puppies. Innovative strategies would be desired to deal with altered gut microbiota in low birth weight puppies aiming to improve their survival and long term health.
Amplicon sequence variant GIT Gastrointestinal tract HBW High birth weight LBW Low birth weight NBW Normal birth weight VIP Variable importance in projection
In the canine species, despite progress in veterinary medicine, neonatal mortality remains relatively high with around one out of ten puppies dying during the first three weeks of life 1,2 . One major mortality risk factor identified recently in puppies and studied in many other mammalian species is the birth weight of newborns. Specifically, low birth weight (LBW) puppies have an 8 times higher mortality risk attributed to lower energy reserves, thermoregulation and vitality compared to normal-birth weight (NBW) and high-birth weight (HBW) individuals 3,4 . Moreover, this lack of vitality, as evidenced by lower APGAR scores, makes the access to mammary glands for colostrum intake difficult for them, resulting in reduced passive immune transfer, and thus higher risk of infectious diseases 5 . High mortality in LBW represents important ethical and economic challenges for breeders and veterinarians, making the study of early risk factors a priority to improve the wellbeing of these vulnerable newborns. Besides, deficit of passive immune transfer and metabolic issues, gut microbial composition may impact newborn health. The gastrointestinal tract (GIT) of mammals harbors trillions of bacteria forming the gut microbiota and playing many different roles in the health of their host, promoting the maturation of the immune system, mucosal integrity, and metabolite production 6,7 . Many studies suggest that the early development of the gut microbiota may impact the infant’s growth during the first months of life and his health until adulthood 8 . Thus, altered gut microbiota development can lead to a higher risk of neonatal mortality and diseases, like enterocolitis, and also