Physiological Responses Influenced by Certain Heavy Metals at the Mullet Fish, Mugil cephalus Inhabiting Mediterranean Sea Coast at Damietta Governorate, Egypt.

The present study aims to determine the concentrations of some heavy metals in the target organs of mullet fish, Mugil cephalus collected from the Coast of Mediterranean Sea, at Damietta Governorate, to compare concentrations of metals in the different organs and their effects on some physiological parameters in the edible organs of this species during winter and summer, 2018.
The present data indicated that the highest values of heavy metals in the different organs were observed during the hot season (summer) than the cold one (winter). It declared the highest value in the gonads for Iron concentration during summer and the lowest one was detected for Cadmium concentration during winter (38.74±4.60 and 1.46±0.33 µg/g wet wt, respectively). Kidneys appeared the same trend with high peak for Iron level followed by Zinc ions during summer; being 153.70±6.24 and 73.34±5.24 µg/g wet wt, respectively. It showed a depletion concentration (1.12±0.17 µg/g wet wt) during winter in Copper ion than the other metals. Due to its function, liver contains the high levels of heavy metals during summer (106.70 ± 16.73 µg/g wet wt) for Iron ion and the lowest values (1.84±0.30 and 1.86±0.37µg/g wet wt, respectively) were measured for cadmium and lead during winter. Data revealed that heavy metals concentration in the musclesof M. cephalus fluctuated between 1.35± 0.73 µg/g wet wt for Copper ion during winter and 51.37± 1.34 µg/g wet wt for Iron during summer. ANOVA (p> 0.05) showed highly significant differences in one way of heavy metals concentrations except between the different organs showed significant difference. Moreover, two ways of analysis exhibited a significant difference (p>0.05) at the interaction between seasons and metals plus between organs and metals.
The present study revealed that total proteins in the different organs of M. cephalus attained its highest value in the muscles during winter and reached its lowest value in the kidney during summer (201.76±13.90 and 84.25 ±4.46 mg/g wet wt, respectively). The maximum values of total lipids were detected in the samples collected during winter (33.28±6.82 mg/g wet wt in the muscles and 31.41±3.43 mg/g wet wt in the liver) while the minimum values were determined during summer in gonads and kidneys; being 12.66±3.83 mg/g wet wt in the former and 13.78±2.64 mg/g wet wt in the latter.
Results exhibited the higher activities in ASAT and ALAT enzymes during summer in the liver while the lower values occurred in the muscles during winter; being 504.46±9.87 and 296.14±24.75 U/g wet wt, respectively for the first enzyme and 363.25±19.73 and 204.62±16.76 U/g wet wt, respectively for the second one.
Concerning analysis of variance for biochemical parameters, there are highly significant differences between the different seasons and parameters of one way. Also, two ways of ANOVA exhibited a significant difference in the interaction between seasons and different parameters.