Growth performance, nutrient utilization, blood indices and immunity of broiler chicks fed diets with graded level of condensed tannins containing Psidium guajava leaf meal

One-hundred-twenty unsexed day-old broiler chicks were randomly distributed into four dietary treatments (T₁, T₂, T₃ and T₄) in a completely randomized block design of 30 birds per treatment, each having three replicates of 10 birds. The birds of T₁, T₂, T₃ and T₄ groups were supplemented with guava leaf meal (GLM) at 0, 1, 2 and 4 per cent of the basal diet, respectively. The overall BW gain was significantly (P<0.05) higher in T₃ and T₂ than T₁, T₄. However, an improved (P<0.05) feed conversion ratio (FCR) was observed in T₃ than that of T₁ and T₂. Apparent digestibility (%) of DM, OM, EE and NFE were statistically similar (P>0.05); however, the CP digestibility differed significantly (P<0.05) among the groups. Nitrogen intake and retention did not differ significantly between groups. Serum levels of total protein did not differ among the groups; however, there was a reduction in albumin and an increase in globulin levels as the level of GLM increased in the diet. Serum total cholesterol and triglyceride levels were lower in GLM supplemented groups compared to the un-supplemented group. The GLM supplementation did not adversely affect alanine amino transferase, aspartate amino transferase, and lactate dehydrogenase activities in broiler chicks. However, incorporation of GLM significantly (P<0.001) improved catalase, reduced glutathione, glutathione-S-transferase and superoxide dismutase activities, and reduced lipid peroxidation. The cell-mediated and humoral immune response attributes were also significantly (P<0.001) with GLM supplementation. It is concluded that GLM supplementation (at 1–2% level) improved body weight gain, FCR, antioxidant indices, immune responses, reduced feed intake, and serum levels of cholesterol and triglycerides.