[Cephalic phase of gastric secretion in dogs. Effect of palatability and caloric intake]

The purpose of this study was to analyze the relative part of the cephalic phase in the gastric secretory and circulating gastrin responses to meals of variable composition and palatability in dogs. Meal palatability was quantified by measuring the ingestion rate of a fixed amount of food. By progressively increasing the amount of carbohydrates or lipids added to a normal meat meal, it was possible to obtain eleven meals of progressively decreasing ingestion rate. When were offered as sham-feeding these eleven meals in dogs fitted with a cervical esophagostomy and a gastric fistula, gastric acid response decreased only after meals of very small ingestion rates. Moreover, neither gastrin, nor gastric pepsin responses changed significantly with ingestion rate of the sham-fed meals. By subtracting the response to sham-fed meals from the response to real meals of identical composition, it was possible to calculate the non-cephalic part of gastric responses. The non-cephalic part of gastric acid secretion and of circulating gastrin was significantly correlated to calorie intake; the slope of the best fitting regression line was greater after lipid meals than after carbohydrate meals. The non-cephalic part of pepsin secretion was very small, if any, and its level was not correlated to the amount of ingested calories. This work suggests that palatability has very little influence on gastric secretion control in dogs.