A continuous dietary supply of free calcium formate negatively affects the parietal cell population and gastric RNA expression for H+/K+-ATPase in weaning pigs.
Baby formula acidification can be used to reduce diarrhea. Calcium formate is a dietary acidifier frequently used in animal weaning diets; it is also a source of available calcium. Gastric acidification reduces gastrin release and hydrochloric acid (HCl) secretion. To study the medium-term effects on fundic gastric mucosa, we fed weaning pigs control diets or diets supplemented with free or fat-protected calcium formate. We evaluated the following: 1) the number of HCl-secreting parietal cells, by immunohistochemistry using an antibody against H(+)/K(+)-ATPase; 2) the number of enteroendocrine cells immunohistochemically stained with chromogranin A (CGA), somatostatin, and histamine (HIS); and 3) the expression of the H(+)/K(+)-ATPase gene, by real-time RT-PCR in the oxyntic mucosa. Cells co-staining for CGA and HIS were defined as enterochromaffin-like (ECL) cells. Pigs fed calcium formate had fewer parietal cells and a lower expression of the H(+)/K(+)-ATPase gene than the controls (P < 0.05). This reduction did not occur in pigs fed fat-protected calcium formate. Somatostatin immune-reactive cells were also more numerous in pigs fed free calcium formate than in controls (P < 0.05). The number of ECL cells was not affected. Using covariance analysis, the number of parietal cells explained part of the differences in the expression of H(+)/K(+)-ATPase gene (positive correlation, r = 0.385, P < 0.01), and excluded the statistical significance of the diet. In the future, the effects on the oxyntic mucosa should be checked when the diet supplemented with calcium formate is discontinued. Furthermore, a reduction in the number of parietal cells could impair the absorption of vitamin B-12 due to a reduced secretion of the intrinsic factor by these cells.
Bosi
Paolo
P
DIPROVAL, University of Bologna, 40064 Reggio Emilia, Italy. paolo.bosi@unibo.it
Mazzoni
Maurizio
M
De Filippi
Sara
S
Trevisi
Paolo
P
Casini
Luisa
L
Petrosino
Gregorio
G
Lalatta-Costerbosa
Giovanna
G
D000821:Animal Feed; D000818:Animals; D002136:Calcium, Dietary / Q000494:pharmacology*; D002452:Cell Count; D004032:Diet; D005744:Gastric Acid / Q000378:metabolism; D005755:Gastrins / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D017506:H(+)-K(+)-Exchanging ATPase / Q000235:genetics*; D007150:Immunohistochemistry; D010295:Parietal Cells, Gastric / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D013270:Stomach; D013552:Swine; D014886:Weaning
D002136:Calcium, Dietary; D005755:Gastrins; D017506:H(+)-K(+)-Exchanging ATPase