90-Day oral (gavage) study in rats with galactooligosaccharides syrup

A 90-day oral (gavage) study was conducted in male and female Sprague Dawley rats to investigate the safety of Vivinal ® galactooligosaccharides (GOS) syrup at 2500 or 5000 mg/kg bw/day. A reference control containing fructooligosaccharides (FOS) was used to match the oligosaccharide and digestible sugars in the test material (approximately 45% and 30%, respectively) and to assess if these had an impact on food consumption. Measurements included clinical observations, body weights, food consumption, hematology, clotting parameters, blood chemistries, urinalysis, ophthalmologic examinations, gross necropsies, organ weights, and histological examinations. There were no effects of feeding GOS syrup at either concentration on any parameter except food consumption. Statistically significant decreases (7–13%) in food consumption were seen in both sexes in the GOS syrup-treated animals at 5000 mg/kg bw/day and animals treated with the FOS control when compared to the reverse osmosis deionized (RODI) water controls. Based on the lack of toxicological effects in the study, the NOAEL for Vivinal ® GOS syrup is 5000 mg/kg bw/day when administered by gavage for 90 consecutive days.