Anthony G. Day

Safety evaluation of a high-lipid algal biomass from Chlorella protothecoides.

Chlorella are traditionally freshwater green algae that have been evaluated for dietary purposes because of their nutritional value. This study investigates the safety of Chlorella protothecoides in a 28-day study. Sprague-Dawley rats were administered 0 (control), 2.5, 5.0, or 10% of their diet for 28days using an FDA Redbook protocol. The average daily dietary intake of algal biomass was determined to be 0, 1794, 3667, and 7557 mg/kg body weight for males and 0, 1867, 3918, and 8068 mg/kg body weight for females. Hematological and biochemical analyses were conducted, and upon completion, gross and microscopic evaluations were performed. No signs of toxicity were observed. Although statistically significant alterations were noted in several parameters among males and females, these changes were deemed to be of no toxicological significance due to the lack of dose-response relationships, the fact that they occurred in only one sex, and the lack of any supporting gross or microscopic alterations. The no-observed-adverse-effect level for the algal biomass under the conditions of this study was considered to be 10% in the diet, the highest dose tested.

Red algal cellular biomass lowers circulating cholesterol concentrations in Syrian golden hamsters consuming hypercholesterolaemic diets

Preliminary evidence suggests that consumption of Porphyridium cruentum (PC) biomass results in hypocholesterolaemic effects; however, mechanisms responsible have not been elucidated. The aim of the present study was to determine whether PC biomass lowers circulating cholesterol concentrations, dose dependently, in hamsters fed hypercholesterolaemic diets for 28 d and determine whether cholesterol biosynthesis is affected. Biomass added to diets at 2.5, 5 and 10% resulted in 14, 38 and 53% reductions (P < 0.001) in total plasma cholesterol, respectively, compared with a control diet. Similarly, non-HDL-cholesterol concentrations in the 5 and 10% PC groups were reduced (P < 0.001) 28 and 45%, respectively, v. controls. These effects were unrelated to cholesterol fractional synthesis rate (FSR), as this did not differ between either treatment or control animals. PC consumption had no effect on food intake, plasma glucose concentrations or energy expenditure, but percentage of body fat was lower (P < 0.001) in the 5 and 10% PC groups compared with controls. These data show that PC reduces total plasma cholesterol and non-HDL-cholesterol when incorporated into the diet at levels as low as 2.5%. The mechanism of action for this reduction may be related to increased excretion since food intakes and cholesterol FSR were not reduced in the animals receiving the PC. In conclusion, the use of PC biomass reduces circulating cholesterol, dose dependently, in hypercholesterolaemic hamsters but not via reductions in cholesterol FSR. There is potential for the use of this biomass as a functional ingredient to aid in the management of blood cholesterol concentrations.