Safety assessment of Asterarcys quadricellulare, a microalga, with applications in poultry and livestock feed

Abstract

Asterarcys quadricellulare (AQ) is a microalgal species with potential applications in improving the quality of animal feed, and safety studies on this species are lacking. Therefore, this study presents safety data on an industrially cultivated strain of AQ tested using the following Organisation for Economic Co-operation and Development (OECD) guidelines: acute skin irritation in rabbits; skin sensitisation in guinea pigs; acute eye irritation in rabbits; acute oral fixed-dose procedure in rats; and bacterial reverse mutation using the B.N. Ames technique. Results showed that AQ is non-irritant and non-sensitising to skin. AQ caused transient conjunctival lacrimation and redness; however, the scores for these clinical signs translated into low ocular irritation indices and classification of AQ as non-irritant to the eyes. An acute oral dose of AQ (2000 mg/kg) did not cause mortality, change in body weight gain, or any general, functional, and neurobehavioral clinical signs. In five strains of Salmonella typhimurium bacteria, treatment with AQ did not cause biologically or statistically significant changes in the number of revertant colonies, indicating that AQ does not cause mutagenic toxicity. This study demonstrates the safety of a heterotrophically-produced strain of AQ and supports its use as a safe and non-toxic feed ingredient.