Effects of dietary Syzygium aromaticum leaf meal supplementation on blood profile and oxidative status of laying hens.

Background: The study examined the effects of dietary supplementation of Syzygium aromaticum leaf meal (SLM) on the haematology, serum biochemistry and antioxidative status of laying hens. Results: A total of 150 20-week-old Isa brown birds were randomly assigned to three experimental diets: Diet 1/control (no supplementation), Diet 2 (0.25% SLM) and Diet 3 (0.50% SLM). Each experimental diet was further divided into five (5) replicates and comprised 10 birds per replicate, that is, 50 birds per experimental diet. The birds were fed with layers mash for 32 weeks of the feeding trial. Blood samples collected in the 32nd week were subjected to haematological and serum biochemical analyses. The dietary supplementation of 0.25% and 0.50% SLM did not significantly (P > 0.05) affect the haematological parameters observed in the layer birds which indicated that SLM did not render the birds anaemic nor compromise their immunity. Likewise, the result of the serum protein (total protein, albumin, globulin and albumin: globulin), serum enzymes (alanine and aspartate aminotransferases) and serum metabolites (creatinine, uric acid and glucose) were not affected (P > 0.05) by the dietary treatment except for the concentration of serum catalase and glutathione peroxidase which was statistically higher (P < 0.05) in layers fed with diets supplemented with SLM compared to the control group, while the serum superoxide dismutase concentration of laying hens was not significantly influenced (P > 0.05). Conclusion: The supplementation of SLM at 0.25% and 0.50% in layers diet can be referred to as a safe additive as the blood indices of birds were not adversely affected. Also, the liver functions which were investigated through the serum enzymes were not impaired and oxidative stress is not triggered in the birds. [ABSTRACT FROM AUTHOR]