Effect of Spirulina platensis as a feed additive on laying performance, egg quality and hepatoprotective activity of laying hens

This study aimed to determine the effect of different dietary levels of Spirulina platensis on the laying performance , egg quality traits and hepatoprotective status of laying hens . A total of 160 Norfa laying hens (38 weeks old) were randomly allocated to one of 4 dietary treatments, with 4 replicates per treatment. The basal diet was used and three additional diets were prepared by supplementing 0.1, 0.2 or 0.3% of Spirulina platensis to the basal diet. The diets were fed to laying hens ad libitum for 8 weeks. Egg production, feed intake, feed conversion ratio , egg weight, egg mass , internal and external egg quality parameters were recorded. Egg yolk cholesterol, serum cholesterol, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) concentrations were measured. Results indicated that supplementation of Spirulina to the diet of laying hens increased ( P< 0.05) their body weight and feed intake compared to the control. Dietary inclusion of Spirulina platensis improved egg number per hen, egg weight, egg production, egg mass and feed conversion ratio (linear, P< 0.05) during the whole experimental period. No significant differences were observed in the egg shape index and the percentages of egg shell, albumen, yolk or Haugh unit by the inclusion of Spirulina platensis in diets. However, hens fed Spirulina platensis had a higher shell thickness ( P< 0.05) than those fed the control diet. Inclusion of Spirulina platensis resulted in a dose dependent increase in egg yolk colour score (linear and quadratic, P< 0.001). A strong positive correlation was observed between the inclusion of Spirulina platensis algae and egg yolk colour score. Dietary supplementation of Spirulina platensis decreased serum cholesterol (linear, P< 0.001) and ALT (linear and quadratic, P< 0.01) and AST concentration (quadratic, P= 0.02). Egg yolk cholesterol concentration was decreased as the dietary concentration of Spirulina algae increased (linear, P= 0.001). These results suggest that Spirulina platensis at a level of 0.3% can be used as a functional natural feed additive to improve laying performance, egg quality and hepatoprotective activity.