This experiment was carried out to investigate the effects of dried chlorella powder (Chlorella vulgaris; DCP) and chlorella growth factor (CGF) on growth performance, serum characteristics, meat qualities and humoral immune responses in broiler chicks. A total of 1050 day-old Ross male broiler chicks were randomly divided into 35 pens (30 chicks/pen) and subjected to one of seven dietary treatments. A non-medicated corn-soybean meal base diet was considered as negative control (NC) and added with either antibiotic (PC), three levels of DCP (NC diets added with 0.05, 0.15 or 0.5 % DCP) or two levels of CGF (NC diets added with 0.05 or 0.15 % CGF). The final body weight and daily weight gain in PC and groups fed diets with 0.15 or 0.5 % DCP were heavier (p < 0.001) than those of NC and CGF-treated groups. Serum total lipid concentrations were lower (p = 0.001) in groups fed diets with 0.5 % DCP and 0.05 or 0.15 % CGF compared with PC group. The levels of serum IgG (p = 0.050) and IgM (p = 0.010) were elevated in chicks fed diets with DCP and CGF compared with the PC or NC group. Meat qualities such as cooking loss, meat color, and pH, of edible meats were not altered by dietary treatments. Collectively, these results indicate that dietary DCP, but not CGF, exerted growth-promoting effect, and both DCP and CGF affected humoral immune response in broiler chicks.

Two experiments were conducted to investigate the dietary effect of chlorella vulgaris on egg production and lutein incorporation into chicken eggs. In Exp. 1, a total of three hundred, 70 wk-old Hy-Line brown layers were divided into six groups with five replicates and fed each experimental diet (corn-SBM based control diet and diets with 0.1, 0.3 or 0.5% chlorella powder and with 0.8 or 2.4% chlorella cultured media) for 6 wk, respectively. The egg production in the groups fed diets containing the chlorella powder and chlorella cultured media were higher than that of the control group (p<0.001). As dietary chlorella levels increased, the yolk color linearly increased. However, there were no significant differences in eggshell qualities. The layers fed diet with 2.4% chlorella cultured media showed the highest Haugh unit value. In Exp. 2, a total of one hundred-eight 80 wk-old Hy-Line brown layers were assigned into four groups with three replicates per group (9 birds per replicate). The birds were fed one of four experimental diets (0, 0.5, 1.0 or 2.0% chlorella powder) for 4 wk, followed by a 14 d feeding of a withdrawal diet devoid of chlorella powder. At 2 wk, the lutein greatly increased with increasing levels of chlorella powder in birds fed diets containing more than 1%. The maximum incorporation of lutein into eggs was reached after 2 or 3 wk of feeding diets with chlorella powder. After a 7 d withdrawal, the lutein contents of egg yolks in the groups fed diets with more than 1% chlorella powder were still higher than that of control group (p<0.05). No significant differences in the lutein levels were found among groups after a 14 d withdrawal period. These results indicated that the use of chlorella in layer diets was effective in improving egg production and egg quality and for the production of lutein fortified eggs.