Critical review evaluating the pig as a model for human nutritional physiology
Résumé
The present review examines the pig as a model for physiological studies in human subjects related to nutrient sensing, appetite regulation, gut barrier function, intestinal microbiota and nutritional neuroscience. The nutrient-sensing mechanisms regarding acids (sour), carbohydrates (sweet), glutamic acid (umami) and fatty acids are conserved between humans and pigs. In contrast, pigs show limited perception of high-intensity sweeteners and NaCl and sense a wider array of amino acids than humans. Differences on bitter taste may reflect the adaptation to ecosystems. In relation to appetite regulation, plasma concentrations of cholecystokinin and glucagon-like peptide-1 are similar in pigs and humans, while peptide YY in pigs is ten to twenty times higher and ghrelin two to five times lower than in humans. Pigs are an excellent model for human studies for vagal nerve function related to the hormonal regulation of food intake. Similarly, the study of gut barrier functions reveals conserved defence mechanisms between the two species particularly in functional permeability. However, human data are scant for some of the defence systems and nutritional programming. The pig model has been valuable for studying the changes in human microbiota following nutritional interventions. In particular, the use of human flora-associated pigs is a useful model for infants, but the long-term stability of the implanted human microbiota in pigs remains to be investigated. The similarity of the pig and human brain anatomy and development is paradigmatic. Brain explorations and therapies described in pig, when compared with available human data, highlight their value in nutritional neuroscience, particularly regarding functional neuroimaging techniques.
Mots clés
AA amino acid
BBB blood–brain barrier
CCK cholecystokinin
Chemosensing
DBS deep-brain stimulation
DVZ devazepide
FA fatty acid
Food intake
GIT gastrointestinal tract
GLP-1 glucagon-like peptide-1
GLU glucose
HSP heat shock protein
IAP intestinal alkaline phosphatase
LPS lipopolysaccharide
MAMP microbial-associated molecular pattern
Microbiota
Nutrition
TAS2R taste receptor type 2
TR taste receptor
VNS vagal nerve stimulation
icv intracerebroventricular
iv intravenous
swine
animal models
human nutrition
TAS1R taste receptor type 1
T1R taste 1 receptor
SUC sucrose
Pig model
PYY peptide YY