Safety assessment of DHA-rich microalgae from Schizochytrium sp. Part V: target animal safety/toxicity study in growing swine

The purpose of this study was to determine the potential toxicity of docosahexaenoic acid (DHA)-rich microalgae (DRM) from Schizochytrium sp., administered in the diet of growing swine. DRM was administered in the diet to groups of castrated male growing pigs (mixed commercial breeds, Landrace & Large White) reared from early weaned (weighing approximately 20 lbs) to approximately 250–270 lbs. Over the course of the 120 day study, animals were fed ad libitum four DRM treatment diets, each designed to optimize weight gain over the growing cycle, and a control diet. DRM was incorporated into the diet of the first treatment group at a level delivering 2.680 kg DRM per pig over the course of 120 days (a constant, whole-life exposure) equating to 598 g DHA per pig. DRM was incorporated into finisher diets only (administered over the last 42 days of the growing cycle) to treatment groups 2, 3, and 4 delivering 1.169, 3.391, and 5.746 kg DRM per pig (261, 756, and 1281 g DHA per pig). These levels represent approximately 1, 3, and 5 times the anticipated commercial dose and were delivered in a feeding strategy designed to mimic commercial use. Vitamin E was added to all diet groups to provide supplementary dietary antioxidant given the high content of polyunsaturated fat in DRM. There were no statistically significant treatment-related effects in clinical observations, body weights, food consumption, mortality, hematologic values, gross necropsy findings, organ weights or histopathology. The only DRM treatment-related changes were higher weight gain and feed conversion efficiency, anticipated results based on the increased fat content in the experimental DRM treatments. This study demonstrates that administration of DRM (at up to five times the anticipated commercial dose) did not produce any treatment-related adverse effects in commercial strains of swine.