MINOR DIETARY SUPPLEMENTATION WITH A PROTEIN HYDROLYSATE IMPROVES ILEAL MUCOSAL INTEGRITY AND NUTRIENT TRANSPORT, POTENTIALLY MEDIATED BY INCREASED GLP-1/GLP-2 SECRETION

Gastrointestinal functionality is regulated by a complex network of receptors exposed to the luminal environment that sense the presence of nutrients and other chemicals, triggering endocrine and neural pathways that ultimately affect physiological and metabolic responses. This is commonly referred to as “gut chemosensing”. Some of these mechanisms have started being explored in pigs, which was the objective of the present work, focusing on a protein hydrolysate (PH) rich in free amino acids that potently activate the porcine umami receptor. With this aim, 96 ((LWxLD)xPietrain) 21d-old weaned piglets were divided into two groups and distributed into 16 pens with six animals each (eight pens/treatment), and offered ad libitum pre-starter/starter non-medicated diets supplemented (PH) or not (CTR) with 1000 ppm of the PH. Individual BW and feed intake per pen were registered weekly during 35 days. On day 35, segments of jejunum and mid-ileum were collected (eight pigs/treatment). Gene expression of nutrient transporters and components of tight junctions (TJ) was assessed in intestinal mucosa samples by RT-qPCR. Furthermore, in vitro assays were performed to evaluate transepithelial electrical resistance (TEER) in Caco-2 cells and to measure GLP-1 secretion in GLUTag cells. Performance data were analysed with a mixed-effect model with repeated measures, and gene expression and in vitro results were analysed with a Student T-Test (SAS, v.9.4). Final BW was improved in the PH group vs. CTR group, 18.5 vs 16.1 kg, respectively (P<0.05). An up-regulation (P<0.05) of TJ and amino acid transport genes was observed in the ileum of the PH group. In vitro data showed an increase in TEER and stimulation of GLP-1 secretion by PH treatment (P<0.01). In conclusion, the addition of minor amounts of a PH may increase piglet performance through the modulation of intestinal integrity and nutrient transport, likely partly associated to the stimulation of GLP-1/-2 secretion.