Effects of soybean lecithin supplementation on growth performance, serum metabolites, ruminal fermentation and microbial flora of beef steers

Abstract This study was aimed to estimate the effect of soy lecithin (SL) on growth performance, serum metabolites, rumen fermentation and microbial flora in Simmental steers. Sixty Simmental steers were randomly assigned to four treatments: control (C), S1 (TMR with 10 g/kg (DM) SL), S2 (TMR with 20 g/kg (DM) SL) and S3 (TMR with 40 g/kg (DM) SL).The ADG of steers fed 10 g/kg, 20 g/kg and 40 g/kg SL was 8.6%, 22.5% and 9.4% higher than that control group, respectively (P 0.05), while some ruminal bacterial with lower abundance showed a linear decrease by increasing the SL supplementation. Therefore, SL supplementation improved growth performance and increased ruminal VFA yields of Simmental steers with no inhibitory effect on the dominant ruminal bacterial. Based on the results of growth performance, the recommended amount of SL supplement is 20 g/kg DM for beef steers.