Influence of dietary fish oil supplementation on humoral immune response and some selected biochemical parameters of broiler chickens

The objective of this experiment was to evaluate the influence of fish oil (FO) supplementation in the diet of broiler chickens on the humoral immune response as well as some blood parameters. Two hundred and sixteen one day old broiler chickens were divided into four dietary groups 0, 1, 2, or 4% FO with 3 replicates of 18 birds. Four chicks randomly selected and marked from each replicate were immunized intramuscularly with 0.2 ml of 5% sheep red blood cells (SRBC) as a non-infectious antigen, at the ages of 15 and 35 days and blood samples were taken 7 days after each immunization. The highest BW was observed in the 2% FO dietary group (T3), followed by T2 (P < 0.01). The serum cholesterol and triglyceride levels significantly decreased in the FO groups at the age of 42 days (P < 0.01). In addition, the inclusion of FO in broiler diets significantly increased the blood glucose (G) level and decreased the total protein (TP), albumin (A) and globulin (GL) concentrations. Fish oil-treated birds had significantly more serum antibody (predominantly immunoglobulin M, IgM) to SRBC than the control group. The highest response to primary and secondary injections of SRBC after 7 days, were detected for group 4 (4% FO), followed by 2% FO group (P < 0.05). The results indicate that the addition of 2 % FO to broiler chick’s diet may stimulate the development of the immune response and improve blood indices, while 4% level was not recommended because of probable off-flavours in the product.