Microalgae Schizochytrium sp. as a source of docosahexaenoic acid (DHA): Effects on diet digestibility, oxidation and palatability and on immunity and inflammatory indices in dogs

Abstract

The objective of this study was to evaluate the effects of the microalgae Schizochytrium sp., as a dietary source of docosahexaenoic acid (DHA), on diet palatability, coefficients of total tract apparent digestibility (CTTAD) of nutrients and metabolizable energy (ME), blood variables and indicators of immunity in dogs. We also evaluated oxidative stability. Two diets containing 0 and 0.4% of microalgae Schizochytrium sp. were evaluated in three experiments. On Experiment I the palatability of diets containing 0% versus 0.4% microalgae was compared. In Experiment II test diets were offered for 30 days to determine digestibility, fecal characteristics, and blood parameters. In Experiment III, the oxidative stability of diets containing microalgae versus anchovy oil was evaluated. There was a higher intake ratio of the diet containing microalgae (p < .05). The ME and CTTAD of nutrients increased (p < .05), except for ether extract after acid hydrolysis, with the inclusion of the microalgae in diet. The amount of monocytes and phagocytic granulocytes was higher (p < .05) in dogs fed 0.4% microalgae. There was greater oxidative stability for the sample containing microalgae. The addition of 0.4% microalgae presented high palatability, increased phagocytic cell numbers, and demonstrated oxidative stability superior to anchovy oil.

Microalgae use in animal nutrition

“…The use of microalgae has increased for several types of animals: cats, dogs, ornamental fish, horses, poultry, swine, sheep, and cow (Spolaore, et al 2006;Souza, et al 2019). Despite that, studies on the inclusion of these organisms in animal nutrition still need to be explored.…”

“…The main microalgae assessed for inclusion in pet diets is Schizochytrium sp. These microalgae may be a promising source for DHA supplementation in diets since it has a high concentration of this fatty acid (approximately 20%) readily available helping to delay the inflammations development (Souza, et al 2019, Souza, et al 2020).…”

“…Besides that, some microalgae generally have a high protein content and a high digestibility (Souza, et al 2019;Sarker, et al 2016), what makes them excellent options to be used in animal feed. The lipid content of microalgae cells can reach up to 90% in dry matter.…”

“…The lipid content of microalgae cells can reach up to 90% in dry matter. In this context, microalgae already available on the market become an alternative (Souza, et al 2019) to replace conventional fonts of lipids.…”

“…Researches have been made to find strategies to scale up highly efficient and cost-effective microalgae production and assess its application in animal health and performance (Souza, et al 2019;El-Bahr, et al 2020;Souza, et al 2020). Despite their potential use in animal feeding, their applications are still limited.…”