RESUMO
The aim of this experiment was to study the effects of dietary addition of high-dose Moringa extract (10 g/kg Moringa extract) on laying performance, haematological parameters, organ index and organ histopathology of Hailan brown laying hens in order to determine the safety limit of Moringa extract in laying hens diet. 270 Hailan brown commercial laying hens with similar body weight were randomly divided into three treatments, 6 replicates per treatment and 15 chickens per replicate. Corn-soybean meal-based diet was used in the experiment, and 0, 0.75 and 10 g/kg extracts of Moringa oleifera were added to the basic diet in the experimental group. The experiment lasted 24 weeks. The results showed that the treatment group given 10 g/kg of dietary Moringa extract had no significant difference in egg-laying performance from the control group (p > .05). Adding 0.75 g/kg Moringa extract had no significant effect on the production performance during the early stage of the experiment (p > .05), but during the later stage, F/E was significantly lower than in the control group (p < .05), and no significantly difference compared with 10 g/kg treatment group (p > .05). The addition of Moringa oleifera extract had no significant effect on serum biochemical indices of laying hens except ALB and UREA (p > .05). The addition of Moringa oleifera extract had no significant effect on blood routine indexes of laying hens except for PLT, MON and HCT (p > .05). The digestive and immune organ indexes of laying hens at the later stage of the experiment (24 weeks) were not significantly affected by the addition of Moringa extract (p > .05) except ceca. There were no obvious abnormalities in histological structure. On the whole, we find it is safe to add Moringa oleifera extract to the diet of laying hens at a dosage of less than 10 g/kg.