The impact of dietary neem leaf on the growth and biochemical traits of rabbits

Neem is a plant used both as food and in traditional medicine. Its many active components, such as Carotenoids, Saponins, Triterpenoids and Nimbidin, may render it a beneficial feed additive for rabbits. Healthy weaned rabbits from breed V-line (VL) were selected to examine the effect of neem (Azadirachta indica) on growth performance, carcass traits, morphology, and blood parameters responses. Thirty-two V-line rabbits (45 days old) were randomly assigned to four groups (n = 8 per group): a control group (G1) receiving a basal diet, and three treatment groups (G2, G3, G4) receiving the basal diet supplemented with 5%, 10%, and 15% neem leaf powder, respectively. Neem leaf supplementation had no significant effect on the rabbits' growth performance, live body weight, carcass weight, lungs and abdominal fat, dressing percentage and liver. There was a significant (P < 0.05) increase in intestine length in G4. Nevertheless, the cecum considerably shrank (P < 0.05) in G3 and G4, which might have a more negative impact on growth performance. Certain biochemical measures (albumin, globulin, triglycerides, LDL, total protein, cholesterol, glucose, AST, and ALT) did not exhibit significant variations. However, a significant (P < 0.01) drop in blood urea occurred after the higher concentration. A significant (P < 0.05) rise in HDL after neem supplementation. Histologically, the liver showed signs of hepatotoxicity in the group supplemented with neem leaves, such as abnormal hepatocytes' nuclear membranes, pyknotic nuclei, karyorrhexis and karyolysis. Additionally, the portal and central veins were congested, and a greater number of Kupffer cells were seen. In conclusion, the findings suggest that dietary neem leaf supplementation may have adverse effects on rabbit health and performance, particularly at higher concentrations.