Diet selection strategies of Grauer's Gorillas (Gorilla beringei graueri) in relation to nutritional benefits and exposure to hepatotoxic phytochemical in Mount Tshiabirimu Forest, Virunga National Park, DRC

Abstract

The study aimed at understanding nutritional benefits and challenges encountered by the current population of Grauer’s gorillas on Mount Tshiabirimu within Virunga National Park. The relative concentrations of selected phytochemicals, nutrients and minerals were determined for eleven priority food plant species using multiple conventional methods. Results showed that all food plants differed with respect to concentrations of saponins, tannins and flavonoids (P<0.05). In addition, the food plants had higher levels of tannins followed by flavonoids, saponins and alkaloids respectively. Further, results demonstrated that food plants contained higher concentrations of carbohydrates followed by ash, dietary fiber, crude protein and lipids respectively. However, the carbohydrates concentration did not differ across food plants (P=0.68). In contrast, the concentrations of lipids, dietary fiber, ash and crude protein were different across food plants (P<0.05). Results also showed that, with the exception of Urera hypselodendron, all the most eaten food plants had the low protein-fiber ratio (below 1) whereas the less frequently eaten plants had high protein-fiber ratio (above 1) excluding Galium chloroionanthum. With respect to minerals, the concentrations of calcium, phosphorous, magnesium, sodium, potassium, copper and iron were different across food plants (P<0.05). Moreover, the concentration of potassium was higher than that of calcium followed by magnesium, phosphorus and sodium respectively across food plants. In addition, results demonstrated that the most commonly fed on food plants tended to have lower concentrations of alkaloids, flavonoids, magnesium, ash and lipids than the less commonly fed on plant species. Notably, the study revealed presence of hepatotoxic alkaloids, deficiency of lipids, sodium and copper in all food plants. The implications of the study findings on gorilla health are discussed.