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

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 the blood, liver, meat, feces, and urine from goats fed finishing diets containing graded inclusions of hempseed cake (HSC). Twenty-five wether goats (26.8 ± 2.9 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 allowed for period of 21 days for adaptation, and blood, fecal, and urine samples were collected on the 28th day of the experiment. The liver and right longissimus thoracis et lumborum were respectively collected at 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, and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) of the blood, liver, and meat linearly increased (P ≤ 0.05) with dietary inclusion of HSC. Blood and liver ferric reducing antioxidant power quadratically increased (P ≤ 0.05) with HSC inclusion reaching a maximum at 50 g/kg dry matter. Current results suggest that inclusion of HSC up to 100 g/kg substituting SBM in goat diets can improve bioavailability of bioactive phytochemicals in the blood, liver, and meat.