Effect of full-fat hemp seed on performance and tissue fatty acids of feedlot cattle

Abstract

Sixty individually penned steers (380 ± 39 kg) were fed barley-based finishing diets containing 0 (control), 9 or 14% full-fat hemp seed (HS) and effects on performance and tissue fatty acid profiles were assessed. At harvest, samples of pars costalis diaphragmatis (PCD) and brisket fat were collected from each carcass. Feeding HS did not affect (P > 0.25) dry matter intake (DMI), average daily gain (ADG), or gain feed-1. Carcass traits were also unaffected (P > 0.35) by treatment. Feeding HS linearly increased (P < 0.001) proportions of C18:0, C18:3 and C18:1 trans-9 in PCD, and 18:2 trans, trans in both PCD and brisket fat. As well, HS linearly increased cis-9 trans-11 CLA (P < 0.001), total saturates (P = 0.002) and polyunsaturated fatty acids (PUFA) (P = 0.01) in PCD. The presence of C20:4, C20:5 and C22:5 was detected only in tissues of cattle supplemented with HS (P < 0.06). Linear reductions (P < 0.002) in C16:1 cis, C17:1, C18:1 cis -9, C20:1, and total unsaturates in PCD, as well as linear decreases in C17:0 (P = 0.04) and C17:1 (P < 0.001) in brisket fat were observed when HS was fed. Levels of HS up to 14% of diet ary DM exerted no detrimental effect on the growth or feed efficiency of cattle as compared to cattle fed a standard barley-based finishing diet. Including HS in the diet had both positive (increased CLA content) and negative (increased trans and saturated fats) effects on fatty acid profiles of beef tissues. Key words: Beef, conjugated linoleic acid, full-fat oilseed, hemp seed, tissue fatty acids