Growth performance and haematological and serum biochemical parameters of broiler chickens given varied concentrations of Polyalthia longifolia leaf extract in place of conventional antibiotics

Abstract

The study was conducted to investigate the effect of Polyalthia longifolia leaf extract (PLLE) in the diet of broiler chickens on their growth performance, nutrient digestibility and blood profile in the finisher phase. A total of 180 broiler chicks were used for the experiment. The birds were weighed on arrival and randomly assigned to 5 treatments and 3 replicates with 12 birds/replicate using a completely randomized design. The data were subjected to analysis of variance using SPSS version 21, and significant means were separated using Duncan’s Multiple Range Test in the same software. Vaccines were given to the birds in all treatments. The birds in treatment group 1 were not given any medication (negative control: without PLLE), T2 served as a positive control (given a conventional antibiotic), and T3, T4 and T5 received 15 g, 30 g and 45 g of Polyalthia longifolia per litre of water, respectively. The inclusion of PLLE had no significant (P > 0,05) effect on growth performance except for average total feed intake and daily feed intake. PLLE reduced the mortality rate of the broilers. Birds receiving 30 g PLLE per litre of water had similar final weight as treatment (T2 – positive control). This established the growth-promoting quality of PLLE in broiler production. Nutrient digestibility parameters were significantly different. Broilers receiving 45 g of PLLE per litre of water had similar nutrient digestibility to those receiving the conventional antibiotic. Birds in treatments 3-5 had significantly higher white blood cell counts, and lymphocyte, neutrophil and red blood cell counts were significantly higher in T3. Cholesterol levels increased with the concentration of PLLE, which indicates its hypercholesterolaemic quality. It was concluded that PLLE can be used without adversely affecting growth performance and thus provides an alternative to conventional antibiotics.