Effect of lupin flake supplementation on rumen fermentation and meat composition of Hanwoo steers

Lupin is considered a potentially rich source of energy and protein for various livestock breeds. However, there are no studies on rumen fermentation and meat composition of Hanwoo (Korean native) steers following supplementation with lupin flakes. In vitro and in situ experiments of lupin flake-supplemented feed were conducted using three Hanwoo cows with rumen fistulae for four weeks. The feeding experiment was conducted using 40 early-fattening Hanwoo steers randomly divided into four groups for 14 months from 16 to 30 months of age, viz., T1, T2, T3, and T4, with feed containing 0%, 3%, 6%, and 9% lupin flakes, respectively. The pH of the ruminal fluid in vitro at 24 and 48 h was higher in T3 and T4 than T1. The rumen levels of acetate, propionate, butyrate, and total volatile fatty acids after 48 h of incubation were lower in the lupin-supplemented groups than in T1. The ruminal pH in situ after 9 and 12 h was higher in T3 than in T1. The strip loin in Hanwoo steers was lighter in T3 than in the other treatment groups. The levels of carnosine, creatinine, adenosine triphosphate, and adenosine monophosphate in the strip loin were higher in T3 and T4 than in T1. The levels of oleic acid and unsaturated fatty acids and the n-6/n-3 ratio tended to be higher in T3 than in T1. Supplementation of livestock feed with 6% lupin flakes had positive effects on ruminal pH and meat lightness, carnosine, creatinine, adenosine triphosphate, and adenosine monophosphate levels in Hanwoo beef.