Egg perivitelline fluid of the invasive snail Pomacea canaliculata affects mice gastrointestinal function and morphology

CAVIEDES VIDAL E; GIGLIO M.L.; HERAS, H.; GARRO, CINTIA

PeerJ Preprints

PeerJ, Inc.

Año: 2018

2167-9843

Background. Pomacea Apple snails are freshwater, amphibious snails native from South America. Some species such as P. canaliculata have become a driver of ecosystemic changes in wetlands and an important rice and taro pest after its introduction to Asia and other parts of the world. Females deposit colored eggs clutches above the waterline, a reproductive strategy that exposes the eggs to harsh conditions and terrestrial predation. However, eggs have no reported predators in their native range, probably by the acquisition of unparalleled biochemical defenses based on a set of proteins (perivitellins) that nourish embryos and protect them from predators and abiotic factors. Notably, ingestion of egg perivitelline fluid (PVF) decreases rat growth rate and alters their gastrointestinal morphology. The aim of the study is to determine the effect of apple snail egg PVF on mice gut digestive activity, morphology and nutrient absorption. Methods. Carbohydrate digestion by intestinal disaccharidases (sucrase-isomaltase and maltase-glucoamilase) was evaluated ex vivo in mice gavaged with 1 or 4 doses of PVF. Gut morphological changes and absorptive surface were also determined. In addition, alteration on nutrient absorption rates, transport pathways and intestinal permeability was evaluated by luminal perfusions of small intestine with radiolabeled L-proline (absorbed by paracellular and transcellular pathways) and L-arabinose (absorbed exclusively by paracellular pathway). Results. PVF affected mice which displayed large morphological changes in the small intestine epithelium inducing the appearance of shorter and wider villi as well as fused villi. This resulted in a diminished absorptive surface, notably in the proximal portion. Likewise, the activity of disaccharidases diminished in the proximal portion of the intestine. Total absorption of L-proline increased in treated mice in a dose-dependent manner. There were no differences neither in the ratio paracellular-to-transcellular absorption of L-proline nor in gut permeability as revealed by the clearance of L-arabinose. Discussion. Oral administration of apple snail PVF to mice adversely alters gut morphophysiology by reducing the intestinal absorptive surface, affecting enzymes of sugar metabolism and increasing the absorption rate of nutrients without affecting the relative contribution of the absorption pathways or gut permeability. These results further support the notion that Pomacea snail eggs possess a passive anti-predator defense targeting the digestive system