Ulvan extracted from green seaweeds as new natural additives in diets for laying hens

Ulvan extracted from the green seaweed Ulva was added in laying hen diets. The effect of ulvan on laying performance, egg quality, immunity function, and antioxidant capacity was evaluated using Hy-Line Brown hens. Six groups of birds (n = 864, 61 weeks old) were fed on the basal diet containing ulvan at 0, 0.05, 0.1, 0.5, 0.8, and 1% for 8 weeks. The results were compared with the control group. Ulvan at concentrations of 0.1 to 1% can significantly improve the egg production (P < 0.05), and higher concentrations (1%) increased the egg weight and decreased feed conversion ratio of hens (P < 0.05). Ulvan at higher concentrations (0.8%, 1%) also helped to improve the eggshell strength (P < 0.05). Ulvan at concentrations of 0.5 to 1% leads to a yolk color to red tendency, and ulvan at concentrations 0.05 to 1% can significantly decrease cholesterol levels of yolk (P < 0.05). Treatments with high levels (1%) of ulvan showed a positive effect on interleukin-6 as well as 0.8% of ulvan on interferon-γ (P < 0.05). There are significant interactions (P < 0.05) on the time × ulvan level on total antioxidative capacity, malondialdehyde, and superoxide dismutase levels of blood serum. These findings thus suggested that ulvan extract can be used as additives in diets for laying hens.