Effects of lipopolysaccharide on the growth performance, nitrogen metabolism and immunity in preruminant calves

To investigate the effect of lipopolysaccharides (LPS) on the growth performance, nitrogen metabolism and immunity in preruminant calves, forty Chinese Holstein male calves were randomly divided into two groups and injected intraperitoneally with 2.5 μg/kg BW of sterile saline or E. coli LPS (Escherichia coli O55: b55) on day 24, 26, and 28. The LPS challenge decreased average daily gain and feed conversion efficiency compared with control group (p<0.05). The urinary concentration of nitrogen (p<0.05) increased, whereas the nitrogen retention decreased (p<0.05) after LPS-challenge. Injection of LPS increased body temperature, serum concentration of IL-1, TNF-α, IL-2 and IgG of calves. In conclusion, LPS-challenge activated immune responses, decreased utilization efficiency of nitrogen, and negatively impacted growth performance of preruminant calves.