Abstract The body composition of Nile tilapia (Oreochromis niloticus) collected from drainage
canals in Al-Ahsa, Saudi Arabia and the concentration of four heavy metals; zinc (Zn), cadmium
(Cd), cobalt (Co) and lead (Pb) in both fish muscles and the water collected from this environment
were assessed across the four seasons. The body composition was found to change with the seasons,
with the best body composition being recorded in autumn and winter, where higher levels of protein

Abstract Oreochromis niloticus, weighing 36.45± 1.12 g were exposed to 10%, 20% and 30% of
the LC50 of CdCl2 which represents treatments (T1)1.68, (T2)3.36 and (T3)5.03 mg/l, respectively,
for a period of 10, 20 and 30 days. It was found that, compared to a control group reading of
0.19 ± 0.03 lg/g dry weight, accumulation of Cd in the gills was significantly (p< 0.05) increased
in samples ranging between 7.64 ± 0.86 and 61.73 ± 0.82 lg/g dry weight from T1 at 10 days to T3

Abstract Fingerlings of Nile tilapia Oreochromis niloticus were exposed to 1.68, 3.36, and 5.04 mg/L
cadmium (as CdCl 2 ), which represent 10%, 20%, and 30% of their previously determined 96-h LC 50 .
After exposure for 20 days, sections of the liver and intestine of treated fi sh were examined histologically.
Histopathological changes varied from slight to severe structural modifi cation, depending on the exposure
concentration. The hepatic tissues of fi sh exposed to 10% LC 50 showed markedly increased vacuolation

Abstract The aimof this study was to evaluate the use of driedmarine seaweed, Gracilaria arcuata for
the first time as dietary ingredient in partial substitution of fishmeal on the growth performance, feed
utilization and body composition of African catfish, Clarias gariepinus. Four experimental diets were
formulated:D1 as a control group;D2; D3 andD4which included 10%, 20%and 30%G. arcuata meal
respectively.One hundred and eighty African catfishweighing 9.62±0.42 g, (mean±SE)was divided

Abstract This study aimed to evaluate the effects of diet containing the green macroalgae, Ulva   lactuca,
on the growth performance, feed utilization and body composition of African catfish Clarias
gariepinus. Four experimental diets were formulated: D1 as a control group and D2, D3 and D4
which included 10%, 20% and 30% U. lactuca meal, respectively. 180 African catfish, weighing
9.59 ±0.43 g, and with an average length of 11.26± 0.21, (mean ± SE) were divided into four