Document Type : Research Paper
M.Sc. Graduate, Department of Animal Science, Shahr-e-Qods Branch, Islamic Azad University, Tehran, Iran
Assistant Professor, Department of Animal Science, Shahr-e-Qods Branch, Islamic Azad University, Tehran, Iran
The objective of this study was to investigate the effects of different levels (0%, 0.3%, 0.6% and 0.9%) of blue-green algae (Spirulina platensis) on performance, egg quality, ovarian parameters and immune system of LSL laying hens at 26-37 wk. of age. One hundred and ninety-two hens were used in a completely randomized design with four treatments and four replications. The effect of algae on daily feed intake, feed conversion ratio, broken eggs percent and egg weight was not significant, but the egg mass improved using 0.6% algae compared with control group (P<0.05). Also, egg production of hens fed the diet with 0.6% and 0.9% Spirulina/kg were higher than treatment 2 (P<0.05). Eggshell breaking strength, eggshell relative weight, eggshell thickness, albumen height and haugh unit were not affected by treatments. However, increasing the dietary levels of Spirulina caused the improvements in eggshell weight and egg yolk color. None of the treatments had significant effects on white and red blood cells, platelets, heterophiles/lymphocytes ratio and concentration of hemoglobin. Dietary treatments did not have significant effects on humoral immunity against SRBC and cell mediated immunity response against PHA injection. But the treatments had a significant effect on the antibody titer in vaccinated birds against Newcastle. In addition, there were no influences of the experimental diets on ovarian different follicles, relative weight of bursa, spleen and carcass. In conclusion, inclusion of 0.6% Spirulina platensis algae in diet increased egg mass, egg yolk color and antibody titer against Newcastle vaccine.