Effect of the levels of Azadirachta indica dried leaf meal as phytogenic feed additive on the growth performance and haemato-biochemical parameters in broiler chicks

Abstract

A study was conducted to evaluate three different levels of Azadirachta indica dried leaf meal, using diets supplemented with 0 (negative control), 1.25 g antibiotic/kg (positive control), 1.25, 2.5 and 5.0 g leaf meal/kg of feed. The chicks were randomly divided into 15 separate floor pens (each 10 × 15 feet) each comprising 20 chicks and three pens (replicates) per treatment group following completely randomised design. At 28 and 42 d BW and feed conversion ratio (FCR) were determined. At 42 d, five birds per pen were slaughtered to measure dressing percentage and lymphoid organs weight was also determined. Serum protein, serum glutamic pyruvic transaminase (SGPT), serum glutamic oxaloacetic transaminase (SGOT), alkaline phosphatase (ALP), serum cholesterol, tissue cholesterol, growth hormone, thyroxine and haematological indices were also determined. At both 28 and 42 d, birds fed diets supplemented with 2.5 g/kg of leaf meal had significantly greater BW and better FCR than those fed diets with 1.25, 5.0 g/kg of leaf meal and controls. There was no significant (p >0.05) difference between BW and FCR when birds fed diets 1.25, 5.0 g/kg of leaf meal and antibiotic (positive control) at any age. There was no significant (p >0.05) effect on mortality at any time during the study. There was no marked variation in dressing percentage between leaf meal supplementation and antibiotic at 28 d of age. However, birds fed diet with 2.5 g/kg of leaf meal had significantly (p <0.05) highest dressing percentage than birds fed diets of 1.25 or 5.0 g/kg of leaf meal and control groups at 42 d of age. The mean lymphoid organs weight of control birds was significantly lower than the birds fed on diets containing leaf meal and antibiotics. Serum total protein was increased (p <0.05) in birds fed leaf meal up to 2.5 g/kg as compared to controls, antibiotic and higher level of leaf meal. The activities of blood enzymes (SGPT, SGOT and ALP) in groups of all broilers supplemented with leaf meal and antibiotic was lower (p <0.05) than negative control group. Serum and tissue cholesterol significantly decreased (p <0.05) with increasing the levels of leaf meal. Non-significant difference was observed amongst controls (positive and negative) and low level of leaf meal. Birds fed on diets containing antibiotic and leaf meal up to 2.5 g/kg had higher (p <0.05) packed cell volume values, red blood cell counts, white blood cell counts, haemoglobin and erythrocyte indices than birds fed diets without leaf meal (negative control) and third dose of leaf meal. It may be concluded that A. indica leaf meal can be included in the diets of broiler chicks up to 2.5 g/kg without any deleterious effects on their performance, serum biochemical constituents and haematological indices. Moreover, the dietary supplementation of A. indica leaf meal may lead to the development of low-cholesterol chicken meat as demanded by health-conscious consumers. © 2012 Taylor & Francis.