Bioavailability of bioactive phytochemicals in selected tissues and excreta from goats fed hempseed cake (Cannabis sativa L.) finisher diets

Abstract

Hempseeds are rich in bioactive phytochemicals, yet little is known about their bioavailability in tissues and excreta of animals fed hemp seed cake. The study evaluated the bioactive phytochemicals and their antioxidant activity in blood, liver, meat, feces and urine from goats fed finishing diets containing graded inclusions of hempseed cake (HSC). Twenty-five wether goats (27 ± 3 kg) of 4-5 months were randomly allocated to five experimental diets containing increasing levels of HSC (0, 25, 50, 75, 100 g/kg DM) substituted for soybean meal (SBM) as the main protein source. Goats were adapted for 21 days, and blood, fecal and urine samples collected on day 28. The liver and right longissimus thoracis et lumborum were respectively collected 60 min and 24 h after slaughter. Linear increases (P ≤ 0.05) in blood, liver and urine magnesium, fecal manganese, and fecal copper were observed with increasing HSC inclusion in the diet. Liver and fecal selenium exhibited a decreasing linear trend (P ≤ 0.05) with HSC increment in diets. Diet did not affect (P > 0.05) meat and urine mineral contents, except urine magnesium. The 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid; ABTS) of blood, liver, and meat linearly increased (P ≤ 0.05) with dietary inclusion of HSC. Blood and liver ferric reducing antioxidant power (FRAP) quadratically increased (P ≤ 0.05) with HSC inclusion reaching a maximum at 50 g/kg DM. Current results suggest that inclusion of HSC up to 100 g/kg substituting SBM in goat diets can improve bioavailability of bioactive phytochemicals in blood, liver, and meat.