Protective efficiency of Thunbergia laurifolia leaf extract against lead (II) nitrate-induced toxicity in Oreochromis niloticus

Thunbergia laurifolia leaf was extracted by using 50% ethanol and supplemented with normal fish food. Oreochromis niloticus (n = 120) were divided into 6 groups by treating with or without 45 ppm of waterborne lead (II) nitrate and feeding normal fish food, fish food supplemented with T. laurifolia leaf extract in low or high dose. After 28 days of treatment, peripheral blood and organs were collected. Growth rate, blood chemistry, hematology and histology were investigated. Fish which were exposed to Pb(NO3)2 and were fed with fish food supplemented with T. laurifolia leaf extract especially in high dose, exhibited higher specific growth rate than fish which were exposed to Pb(NO3)2 and were fed with normal fish food. Moreover, T. laurifolia leaf extract can normalized blood chemistry, hematological and histological parameters in Pb(NO3)2-treated O. niloticus. We conclude that T. laurifolia leaf clearly reduced toxicity and is able to promote growth performance in O. niloticus after Pb(NO3)2 exposure.