Study on the effect of consumption period of fish oil on serum concentration of cholesterol and triglyceride and antibody response in broiler chicks

The aim of the present study was to determine the optimal time of fish oil inclusion in broiler feed formulation on antibody response and concentration of serum cholesterol and triglyceride. A 49 day study was conducted on 600 one-day old chicks from a commercial hybrid (Ross) which were randomly allocated to 6 groups. The control group was fed a diet containing 5 % corn oil and in experimental groups the fish oil was substituted for corn oil from 2,3,4,5 and 6 weeks. Serum concentration of cholesterol and triglyceride were determined on days 37 and 44. Titer of antibody against sheep red blood cells (SRBC) were determined 7 days after immunization on days 30 and 37. Supplementation of diet by fish oil did not affect concentration of serum cholesterol. However, concentration of serum triglyceride decreased significantly (p<0.01). Titer of IgG against SRBC was affected in first injection (p<0.01) and the maximum antibody response was seen in control group and chickens feeding fish oil for 2 weeks, and antibody response decreased with increase of consumption length of fish oil. Titer of IgM in the second injection (p<0.05) were affected by dietary treatments. Chickens which were fed fish oil for 2, 3 and 4 weeks had higher antibody response than other treatments.