Минеральный состав гастролитов в желудках утиных в Приморском крае и значение кремниевых минералов в физиологии птиц

Abstract

The function of gastroliths contained in the stomachs of birds is still not fully explored. In our research we described the mass, size, and composition of gastroliths from 96 stomachs of 12 Anatidae species harvested in 2012 and 2014 in the south of Primorsky Region. The mass of gastroliths from one stomach was up to 3.80 g in ducks and 27.22 g in geese. In 65–85% of cases the gastroliths consisted of quartz. Of other minerals we found feldspars, impurities of other silicates and aluminosilicates, carbonates, ore and other minerals. The function of gastroliths is discussed on the basis of the obtained results on their composition and the review of literature data. The analysis shows that birds instinctively ingest mineral grains for adjusting the chemical composition of the digestive electrolyte. The removal of excess chemicals from the body occurs with the participation of silica gels formed in the neutral and slightly alkaline environment of the intestine from microcrumbs of siliceous minerals, which are produced in the muscular section of the stomach as a result of mechanochemical interaction of gastrolith grains. In addition, gastroliths have other functions, including the prolongation and activation of digestive enzymes, food grinding, and others.