INTRODUCTION
Gastric juices are liquids found in the stomach. They contain numerous compounds, including hydrochloric acid (HCl), pepsin, lipase, mucin, intrinsic factor, peptides, nucleic acids and electrolytes[1]. Additionally, they may also contain salivary constituents due to swallowing, bile due to gastroduodenal reflux and inflammatory mediators or blood from damaged gastric walls[2]. In their normal state, gastric juices are usually clear in color.

HCl is an important component in gastric juice. It is a strong acid produced by the parietal cells in the corpus generating a gastric pH of 2-3[1]. Activation of pepsin and absorption of nutrients relies on an acidic pH in the stomach. HCl is also important in protecting the stomach and intestines from pathogens. Increased gastric pH induced by disease process, reflux of bile or pharmaceuticals allows for bacterial overgrowth in the stomach[3]. These pathogenic bacteria in the hypochlorhydria stomach can produce nitrite and nitroso-compounds, which act as one of the triggers in the atrophy-metaplasia-dysplasia-carcinoma pathway[4].

Helicobacter pylori (H. pylori) infection is an important biological factor which can induce marked alterations in gastric acid secretion of hosts[5,6].
- Need data on macaque, chimp, walrus, frugivore, carnivore pH.