Abstract: The effect of ω6/ω3 polyunsaturated acids (PUFA) ratios on the gain weight, immunological performance in Arber Acre (AA) broilers was investigated in this study. Total of ninty female birds were distributed across 5 treatment groups, which were supplemented with 30∶1,20∶1,10∶1,5∶1,2.5∶1 PUFA of ω6/ω3. At 56 days of age, each treatment was divided into two groups and chickens were injected with lipopolysaccharide (LPS) or saline for 3 days respectively. The results showed that no differences were found between the five supplementation (P>0.05) in the following traits: the gain weight, the level of total protein (TP) and IgG (P>0.05). Significant differences occurred in albumin (Alb), the antibody titre of New Castle Disease virus (ND) and cortisone concentration among the five dietary treatment. There was significant change in the gain weight between LPS and Saline treatments (P<0.05). The cortisone concentration of the first day was higher than that in the seventh day after injection. The reverse tendency was found for the level of IgG, TP and the Alb in the same time. Therefor,immune performance of AA broilers was influenced supplemented with ω6/ω3 PUFA. The average of TP and Alb in 20∶1 treatment and the antibody titre of ND in 2.5∶1 treatment were higher than other treatments.

Key words: polyunsaturated fatty acids; lipopolysaccharide; Arber Acre broiler; immunological performance