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

GIGLIO, MATIAS; GARRO, CINTIA; CAVIEDES VIDAL, ENRIQUE; HERAS, HORACIO

PeerJ

PeerJ Inc

Año: 2018 vol. 6

2167-8359

Background. Species beloging to the genus Pomacea (Ampullariidae), often referredas apple snails, are freshwater, amphibious snails native to South, Central and NorthAmerica. Some species such as P. canaliculata have become a driver of ecosystemchanges in wetlands and an important rice and taro pest after its introduction to Asiaand other parts of the world. Females deposit colored egg clutches above the waterline, areproductive strategy that exposes the eggs to harsh conditions and terrestrial predation.However, eggs have no reported predators in their native range, probably because ofthe acquisition of unparalleled biochemical defenses provided by a set of proteins(perivitellins) that nourish embryos and protect them from predators and abioticfactors. Notably, ingestion of egg perivitelline fluid (PVF) decreases rat growth rateand alters their gastrointestinal morphology. The aim of the study is to determine theeffect of apple snail egg PVF on mice gut digestive activity, morphology and nutrientabsorption.Methods. Carbohydrate digestion by intestinal disaccharidases (sucrase-isomaltase andmaltase-glucoamylase) was evaluated ex vivo in mice gavaged with 1 or 4 doses of PVF.Changes in gut morphological and absorptive surface were measured. In addition,alteration on nutrient absorption rates, transport pathways and intestinal permeabilitywas evaluated by luminal perfusions of small intestine with radiolabeled L-proline(absorbed by paracellular and transcellular pathways) and L-arabinose (absorbedexclusively by paracellular pathway).Results. Perivitelline fluid affected mice displayed significant morphological changes inthe small intestine epithelium inducing the appearance of shorter and wider villi as wellas fused villi. This resulted in a diminished absorptive surface, notably in the proximalportion. Likewise, the activity of disaccharidases diminished in the proximal portion of the intestine. Total absorption of L-proline increased in treated mice in a dosedependentmanner. There were no differences neither in the ratio of paracellular-totranscellularabsorption of L-proline nor in gut permeability as revealed by the clearanceof L-arabinose.Discussion. Oral administration of apple snail PVF to mice adversely alters gutmorphophysiology by reducing the intestinal absorptive surface, affecting enzymes ofsugar metabolism and increasing the absorption rate of nutrients without affectingthe relative contribution of the absorption pathways or gut permeability. These resultsfurther support the role of PVF in passive anti-predator defenses in Pomacea snail eggsthat target the digestive system.