Annatto seeds as Antioxidants Source with Linseed Oil for Dairy Cows

SIMPLE SUMMARY: Currently, functional foods are gaining widespread attention. Polyunsaturated fatty acids (PUFA) and antioxidant compounds have beneficial effects on health. It is possible to increase the concentration of these compounds in the milk obtained from dairy cows by manipulating their diets, thereby improving milk quality and consequently the health of animals and humans who consume this milk. Annatto seed (Bixa orellana L.) is a source of antioxidants, whereas linseed oil is rich in omega 3 fatty acid. We evaluated the inclusion of annatto seeds and linseed oil in the diets of dairy cows and their effects on dry matter intake (DMI), nutrient digestibility, milk yield, milk composition and antioxidant capacity in milk and blood. There was no effect of treatment on nutrient digestibility and antioxidant capacity, but the addition of annatto seeds decreased DMI and milk production and linseed oil supplementation reduced milk fat content. ABSTRACT: This study aimed to evaluate the effects of annatto seeds, linseed oil and their combination on DMI, apparent total tract digestibility, antioxidant capacity and milk composition of dairy cows. Four lactating Holstein cows (120 ± 43 days in milk; 15.98 ± 2.02 kg of milk/day, mean ± SD) were allocated in a 4 × 4 Latin square with a 2 × 2 factorial arrangement (with or without annatto seeds at 15 g/kg of dry matter (DM); with or without linseed oil at 30 g/kg of DM) and provided four different diets: control (no annatto seeds or linseed oil); annatto seeds (15 g/kg of DM); linseed oil (30 g/kg of DM); and a combination of both annatto seeds and linseed oil. Annatto seeds reduced DM intake, and milk yield, protein and lactose, but increased content of fat, total solids and short chain fatty acid, with no effect on total antioxidant capacity of milk. Linseed oil supplementation decreased medium chain fatty acid proportion and n-6/n-3 ratio, conversely it increased long chain fatty acids and n-3 fatty acid content of milk, ether extract intake and total-tract digestibility. Thus, linseed oil supplementation in dairy cow diets improved the milk FA profile but decreased milk fat concentration, whereas annatto seeds did not influence antioxidant capacity and depressed feed intake and milk yield.