Effects of dietary lead exposure and graded levels of ascorbic acid supplementation on performance and haematology of broiler chickens

Abstract

The effects of dietary lead acetate (LA) exposure on growth performance and haematological characteristics of broiler chickens and possible  ameliorative effect of ascorb ic acid (AA) were investigated. One hundred and twenty day-old broiler chicks were randomly divided into six treatment groups of 20 birds with two replicates. Six isonitrogenous and isocalories experimental diets were compounded and fed to birds for seven weeks: T₁ (control) received diet I (0mg of LA and AA/kg feed), T₂ received diet II (200mg LA/kg feed), T₃ received diet III (200mg LA and 50mg AA/kg  feed), T₄ received diet IV (200mg LA and 100mg AA/kg feed), T₅ received diet V (200mg LA and 150mg AA/kg feed) and T₆ received diet VI (200mg LA and 200mg AA/kg feed). Finally, two birds per replicate were randomly selected, weighed and slaughtered. For haematology, blood samples were collected into labelled EDTA - bottles. PCV, RBC, WBC and Hb concentration were determined using Auto Haem analyzer. T₂ showed significantly (P<0.05) decreased body weight and dressed weight than the control. Although depressive effects of LA on body weight gain, feed intake and feed conversion ratio were significant. Birds in other treatments compared favourably with the control. Dietary lead significantly (P<0.05) reduced  WBC in T₂, while it significantly (P<0.05) and nonsignificant (P>0.05) lowered haemoglobin and RBC in T2 and T6 respectively. The PCV was numerically lowered in T₂ and T₆. However, haematology of AA treated groups, especially those of T₃and T₄ compares favourably with the
control. In conclusion, dietary lead exposure negatively affects growth performance and haematology of broilers, which was ameliorated by as low as 50mg AA/kg diet supplementation.