Pure basil oil which has antimicrobial and immunostimulant effect in the cultured fish was formulated into nanoemulsion using homogenizer. Basil oil nanoemulsion characters, its effect as antimicrobial in vitro and its resistant against Aeromonas hydrophila were studied. The results revealed that the droplet size distribution of the basil oil nanoemulsion measured 6.419 nm in diameter with poly dispersity index (PDI) value 0.753, Zeta potential-1.01mV, pH value 5.55, the conductivity 203.5 µS/m and the viscosity 0.887 mpascal/sec. Basil oil nanoemulsion had antibacterial effect at 6µl concentration against Aeromonas hydrophila, Aeromonas veronii, Pseudomonas fluorescens and Streptococcus agalactiae while, at 3µl concentration had antifungal effect against Saprolegnia parasitica. Minimum inhibitory concentration (MIC) of this formulation of basil oil differ among the examined bacterial isolated from 3-9 µl. Basil oil nanoemulsion save for Oreochromis niloticus at 8.5% of fish body weight for 14 days and increased fish resistance. Moreover, basil oil nanoemulsion showed different effects against A. hydrophila by using ultrastructure electron microscope which were discussed in this study.

Pharmacokinetics Doxycycline dose HPLC African catfish (Clarias gariepinus) aquaculture has experienced widespread production and has lately gained considerable interest in Egypt. Doxycycline (DOX) is used to control certain common fish's bacterial diseases, such as Septicemia, Fin rot, Columnaris, and Tail Rot. Therefore, our experiment was conducted to assess the pharmacokinetic properties of single doxycycline dose (20 mg/kg BW) orally administered in the African catfish. DOX plasma levels were measured using HPLC with a limit of detection nearly 0.035 µg/ ml, and then were undergoing compartmental analysis; a onecompartment model was detected. The doubled-peak phenomenon was identified after oral administration and the 1 st peak concentration (C max1) and the 2 nd peak concentration (C max2) in plasma were 2.29±0.46 and 1.68±0.33µg/mL at 1 st and 8 th h respectively, the absorption half-life (t 1/2ka) was 0.045 h, the elimination half-life (t 1/2ke) was 5.81 h, systemic total body clearance (Cl) was 0.72 mL/h/kg, volume of distribution of the central compartment (V d /F) was 5.74±1.11 L. These findings suggested that DOX was to some extent rapidly absorbed, widely distributed, and slowly excreted; moreover, it could be subjected to enterohepatic recycling.

Bacterial pathogens are the most serious agents causing diseases in both wild and cultured fish resulted in massive mortalities and economic losses. Motile Aeromonas Septicemia (MAS) is a prevalent bacterial disease caused by Aeromonas hydrophila (A. hydrophila) that impacts freshwater fish. This research aimed to evaluate doxycycline (DOX) antibacterial activity against A. hydrophila both in vitro and in vivo. The minimum inhibitory concentration (MIC) and mutant prevention concentration (MPC) of DOX against A. hydrophila previously isolated from African catfish (Clarias gariepinus) were determined to be 0.78µg/mL and 3.9μg/mL, respectively. For in vivo experiment, a total number of 80 apparently healthy African catfish, were distributed randomly into four equal groups. Group 1 (non-infected, non-treated) was kept as control, Group 2 (non-infected and treated) was non-infected and treated with 20 mg/Kg BW of DOX for 5 successive days in feed, Group 3 (infected) was inoculated intraperitoneally (IP) with A. hydrophila (2× 10 8 CFU/ mL) and Group 4 (infected and treated) was infected with A. hydrophila then treated with 20 mg DOX/Kg BW. Our results revealed 70% mortality in African catfish experimentally challenged with A. hydrophila (Group 3). Moreover, significant elevation of serum alanine aminotransferase (ALT) (89±16.26, 54.67±6.44, 36±5.29 U/L, respectively), aspartate aminotransferase (AST) (195±7.64, 221.33±17.9, 211.33±12.72 U/L, respectively) and creatinine (0.68±0.098, 0.76±0.052, 0.58 ±0.023 mg/dL, respectively) was observed on 1 st , 7 th and 14 th days post treatment. While treatment of the infected fish (Group 4) with DOX decreased the mortality rate to 30 %, improved the clinical signs and significantly reduced serum ALT (30.67±6.01, 22.67±1.86 U/L, respectively) and AST (153±7.57, 147.67±6.7 U/L, respectively) on 7 th and 14 th days post treatment. Also, it significantly decreased creatinine (0.21±0.026, 0.25±0.047, 0.21±0.053 mg/dL, respectively) levels at 1 st , 7 th and 14 th days post treatment when compared with those of Group 3. The results showed that DOX could be used as an effective treatment against A. hydrophila infection in African catfish with little adverse effects.

In the present study, 120 fish specimens (64 male and 56 female) of the five-lined snapper, Lutjanus quinquelineatus of variable sizes were used for demonstration the morphometric and meristic characteristics of this species in the Egyptian Red Sea, Hurghada fishing area. The total length varied from 15.3 to 28.7 cm in males and from 16.0 to 31.7 cm in females while their weights ranged between 44 and 378 g in males and between 48 and 512 g in females. This fish species showed constant meristic characters. Statistical interpretation of morphometric data indicated that there is direct relationship between total body length with head length (HL), snout length (SnL), eye diameter (ED) and length of caudal peduncle (CPL). The meristic characters like dorsal fin rays, anal fin rays, lateral line scales, gill rakers on lower arm and scales in transversal line were counted. The results revealed that there is no sexual dimorphism in L. quinquelineatus from Hurghada fishing area. MATERIALS AND METHODS Morphometrics: In the present investigation, 64 males (15.3-28.7 cm in TL) and 56 females (16.0-31.7 cm TL) of L. quinquelineatus, were randomly collected from the southern Red Sea, Hurghada, fishing port, Egypt during the period from January to December 2016. Sex was determined by macroscopic examination of the gonads, and this subset was used to test the hypothesis of no sexual dimorphism in morphometric and meristic characters of L. quinquelineatus. For each fish, 18 morphometric measurements were made on the left side up to the nearest millimeter using a divider and a measuring board. The following is a list of these measurements, which are diagrammatically represented in Figure 1; its corresponding number indicated in such a list labels each measurement on this figure. Those morphometric measurements included: 1-Total length (TL) 2-Standard length (SL) 3-Body depth (BD) 4-Caudal peduncle depth (CPD) 5-Head length (HL) 6-Predorsal fin length (PRDFL) 7-Head depth (HD) 8-Preventral fin length (PRDFL) 9-Distance between ventral and dorsal fins origin (VDOL) 10-Distance between anal and dorsal fin ends (ADFEL) 11-Dorsal fin base length (DFBL) 12-Distance between the ventral fin origin and the end of anal fin (VOAEFL) 13-Distance between the first spine of the dorsal fin and the end of anal fin (SPDAEFL) 14-Distance between dorsal fin end and ventral fin origin (DEVOFL) 15-Distance between the ventral fin and the end fin origin (VEADFL) 16-Distance between dorsal fin end and dorsal caudal fin origin (DEDCF) 17-Distance between anal fin end and ventral caudal fin origin (AEVCFL) 18-Eye diameter (ED) Meristics: Certain meristic counts of 64 males and 56 females of L. quinquelineatus were considered. The following meristic counts were recorded: 1-Number of the dorsal fin spines (DFS) 2-Number of the dorsal fin soft rays (DFSR) 3-Number of the pectoral fin rays (PFSR) 4-Number of the ventral fin rays (VFR) 5-Number of the ventral fin spines (VFS) 6-Number of the anal fin rays (AFR) 7-Number of the anal spines (AFS) 8-Number of th...