Effect of polysavone (alfalfa extract) on abdominal fat deposition and immunity in broiler chickens

Two hundred 1-day-old male commercial Arbor Acres broiler birds were randomly distributed to a control group and a polysavone group (5 replicates of 20 birds each) to investigate the influence of polysavone, a natural extract from alfalfa, on abdominal fat deposition and immunity in broiler chickens. Birds in the control group were supplied with a basal diet, and 0.06% polysavone was added to the basal diet of birds in the polysavone group. Body weight and feed consumption for each replicate were recorded weekly. At 3, 4, 5, and 6 wk of age, 4 birds from each replicate were randomly selected for blood and organ sampling. Polysavone had no significant effect on feed intake, BW, or feed:gain ratio in the experimental period, and it decreased the abdominal fat weights at 5 and 6 wk of age. Polysavone improved (P <0.05) the relative thymus and spleen weights at 6 wk of age and the bursa weights at 4 and 5 wk of age compared with the control group. At 4 and 6 wk of age, the proliferation of T and B lymphocytes in the polysavone group was significantly greater (P <0.05) than that in the control group. When birds were 4 and 5 wk of age, polysavone resulted in a significant increase (P <0.05) in serum anti-Newcastle disease virus hemagglutination inhibition antibody titer. These results showed that polysavone may decrease abdominal fat deposition and enhance immunity without an adverse effect on the performance of broiler chickens.