Table 2.

α-Tocopherol composition of feedstuffs (mg/kg of DM ± standard deviation).

Item	Total α-tocopherol	Natural α-tocopherol1	Synthetic α-tocopherol2	RRR-α-tocopherol3	Synthetic 2R-α-tocopherol4	2S-α-tocopherol5	α-Tocotrienol6	γ-Tocopherol7
Oat	6.9 ± 0.16	6.9 ± 0.16	ND	6.9 ± 0.16	ND	ND	13.2 ± 0.90	1.6 ± 1.24
Decorticated oat	7.7 ± 1.14	7.7 ± 1.14	ND	7.7 ± 1.14	ND	ND	17.7 ± 2.19	1.6 ± 0.52
Toasted oat	5.1 ± 0.98	5.1 ± 0.98	ND	5.1 ± 0.98	ND	ND	2.4 ± 1.26	0.2 ± 0.07
Toasted decorticated oat	3.6 ± 1.39	3.6 ± 1.39	ND	3.6 ± 1.39	ND	ND	1.5 ± 1.24	ND
Toasted fava beans	2.0 ± 2.79	2.0 ± 2.79	ND	2.0 ± 2.79	ND	ND	0.3 ± 0.29	40.3 ± 4.67
Grass clover silage	57.2 ± 16.11	57.2 ± 16.11	ND	57.2 ± 16.11	ND	ND	ND	6.4 ± 3.11
Mineral and vitamin supplement	5,534 ± 0.0	ND	5,534 ± 0.0	728 ± 0.0	2,075 ± 0.0	2,767 ± 0.0	ND	ND

ND = not detected.

¹Natural α-tocopherol originates from feedstuffs.

²Synthetic α-tocopherol originates from vitamin supplement.

³RRR-α-tocopherol (2R-(4′R, 8′R)-5,7,8-trimethyltocol) originates from feedstuffs and vitamin supplement.

⁴Synthetic 2R-α-tocopherol is summation of RRS (2R-(4′R, 8′S)-5,7,8-trimethyltocol), RSR (2R-(4′S, 8′R)-5,7,8-trimethyltocol) and RSS-α-tocopherol (2R-(4′S, 8′S)-5,7,8-trimethyltocol).

⁵2S-α-tocopherol is summation of SRR (2S-(4′R, 8′R)-5,7,8-trimethyltocol), SSR (2S-(4′S, 8′R)-5,7,8-trimethyltocol), SRS (2S-(4′R, 8′S)-5,7,8-trimethyltocol), and SSS-α-tocopherol (2S-(4′S, 8′S)-5,7,8-trimethyltocol).

⁶α-Tocotrienol (2R-(4′R, 8′R)-5,7,8-trimethyltocotrienol).

⁷γ-Tocopherol (2R-(4′R, 8′R)-,7,8-dimethyltocol).