Daily pH fluctuations in the gastrointestinal tract of Senegalese sole and gilthead seabream juveniles in relation to different feeding protocols

Abstract

Gastrointestinal tract (GIT) pH is an important factor involved in gut enzymatic capacity and the consequent bioavailability of ingested nutrients, solubilization of proteins and minerals, and modulation of the gut microbiota. Moreover, GIT pH may be affected by several factors including fish age, feeding schedule, and food quality, among others. More accurate pH measurements are needed to have a general picture of the complex processes occurring during the feed transit and, therefore, to define efficient feeding protocols. Nevertheless, the information on the luminal pH through the digestive tract in fish is scarce. Therefore, the aim of the present work was to know the ionic luminal pattern under different feeding conditions in two important aquaculture species, with very different digestive anatomies, Senegalese sole (Solea senegalensis) and gilthead seabream (Sparus aurata).