Monosex Nile Tilapia Oreochromis Niloticus Research Articles

Influence of Fluctuating Water Temperature and Dietary Oxytetracycline on the Safety of Monosex Nile Tilapia Oreochromis niloticus Fries.

The influence of fluctuating water temperature and dietary oxytetracycline (OTC) at 0 (0X), 80 (1X), 240 (3X), 400 (5X) and 800mg (10X)/kg biomass/day for 30 consecutive days on the safety of monosex (all male) Nile tilapia Oreochromis niloticus fries in terms of feeding, growth, survival and histopathology of vital organs were assessed. A dose-dependent decline in feed intake and biomass was recorded. The OTC-dosed groups recorded higher mortalities than the control. The therapeutic OTC-dosing (1X) in conjunction with low temperature caused 75.56 ± 8.01% mortality and 25.75% reduced feed intake in 30days. The mortalities increased with increasing OTC-doses from 85.19 ± 3.39% (1X) to 95.56 ± 2.22% (10X) and fluctuating temperature (12.00-21.50°C) even after the withdrawal of OTC. Relatively mild to moderate histopathological lesions were observed in the kidney, liver and intestine of OTC-dosed fries. These results suggested that dietary OTC and low water temperature may cause adverse effects on monosex O. niloticus fries.

Water quality and health status of the monosex Nile Tilapia, Oreochromis niloticus cultured in aquaponics system (ASTAF-PRO)

The present study is a part of a cooperative project to enable the efficient transfer of innovative ecotechnology ASTAF-PRO aquaponic from Germany to Egypt for sustainable aquaculture and food production. The present part was carried out to evaluate the impact of ASTAF-PRO aquaponic system on water quality parameters and the health status of the monosex Nile tilapia Oreochromis niloticus. Water quality analysis revealed an improvement of most parameters in an aquaponic system with a significant reduction in toxic ammonia. In aquaponic, the nitrite level in ASTAF-PRO was lower than the permissible limit, probably because of the double-sided action of nitrobacteria present in the biological filters and the grow beds of the plant in the system. No significant difference was observed in the values of nearly all the hematological parameters in the blood of fishes reared in the aquaponic system and those reared in POND systems, being always within the normal ranges for the healthy Nile tilapia. Most of the measured biochemical variables exhibited an improvement in the blood of fish reared in the ASTF-PRO system compared to that of the POND. This suggests that fish health improved when reared in aquaponic with better water quality parameters. Immunoglobulin (IgM) levels and lysozyme activity were the same in the blood of fish reared in both systems, confirming that the monosex Nile tilapia was still fit with a good immunological status under aquaponic condition. In conclusion, the health status of the monosex Nile tilapia reared in ASTAF-PRO aquaponic system was better than those reared in POND in terms of hematology, biochemistry and immunological status. Obviously, the difference in the health status of fish in different systems can be linked to water quality since the same feed was used.

Physiological and oxidative stress biomarkers in the freshwater monosex Nile tilapia, Oreochromis niloticus L., exposed to pendimethalin‐based herbicide

Fish are relatively sensitive to changes in their surrounding environment, including increasing pollution. Therefore, the present study was undertaken to evaluate the impact of contamination with the pendimethalin-based herbicide; Stomp(®) 50% EC (50% pendimethalin as emulsive concentrate) on adults of the monosex Nile tilapia Oreochromis niloticus L. A total of 260 fish with body weights of 90 ± 5.0 g were used in the determination of the 96-h LC50 value and of the impacts of acute exposure to pendimethalin on physiological parameters, and oxidative stress and antioxidant biomarkers. The 96-h median lethal concentration (96-h LC50 ) value of pendimethalin for monosex Nile tilapia was determined as 4.92 mg/L. Abnormal behavioral responses of the fish and the toxic symptoms of pendimethalin exposure are described. Acute exposure to pendimethalin induced leukocytosis, hyperglobulinemia, and hyperglycemia, but resulted in nonsignificant changes in other hemato-biochemical parameters. Moreover, pendimethalin increased lipid peroxidation (LPO) and decreased levels of reduced glutathione and antioxidant enzymes; superoxide dismutase, catalase, and glutathione reductase in both liver and gill tissues, in a time-dependent manner, with maximum alterations observed in the gills rather than the liver. We conclude that although pendimethalin is moderately toxic, it does not cause hepatorenal toxicity. However, this herbicide pollutant induces major disturbances to the antioxidant system; induction of oxidative stress and LPO is the proposed toxicodynamic pathway for such stress.