In the present study, Indian shrimp, Penaeus indicus, were fed on diets supplemented with basil (Ocimum basilicum) oil (BO) to observe the growth performance, antioxidant and innate immune responses, and the resistance against Vibrio parahaemolyticus infection. The animals (5.0–5.5 g) were fed on diets supplemented with 0.0 (control), 1.0, 2.5 and 5 g BO/kg diet over 90 days. After the feeding trial, animals were intramuscularly injected by V. parahaemolyticus and observed for 96 h for mortality or any abnormal signs. Growth‐stimulating effects of dietary BO supplementation on final weight, weight gain percentage, specific growth rate and feed intake were observed. No significant differences were found in feed conversion ratio, protein efficiency ratio, protein productive value and animal survival. Feeding the animals on BO‐enriched diets did not significantly affect the chemical proximate composition of animals’ muscles. Increased values of total protein, albumin and globulin were observed in BO‐fed animals; meanwhile, aspartate and alanine aminotransferases as well as creatinine and urea levels significantly decreased in animals fed 2.5–5.0 g BO/kg diet. Activities of superoxide dismutase, catalase, glutathione peroxidase, lysozyme and phenol oxide activity significantly (p < .05) increased in the BO‐fed fish, with highest values in treatments of 2.5–5.0 g/kg diet. The dietary BO supplementation significantly (p < .05) decreased levels of malondialdehyde and nitrous oxide. After the bacterial challenge, 66.7 percent of animals in the control group were dead. The BO‐fed animals were more resistant against bacterial challenge especially at levels of 2.5–5.0 g/kg diet, which showed high relative percentage of survival (80.0–86.7 percent). In conclusion, dietary BO supplementation with levels of 2.5–5.0 g/kg diet proved beneficial effects to Indian shrimp where growth performance, antioxidant systems and innate immunity were stimulated. It also promoted the challenge of Indian shrimp against V. parahaemolyticus infection.

A 180‐d trial was done to evaluate the effect of stocking different ratios of Nile Tilapia Oreochromis niloticus, Striped Mullet Mugil cephalus, and Thinlip Grey Mullet Liza ramada on production and economic return in brackish‐water ponds. The trial was conducted in twelve 3,000‐m2 earthen ponds with four treatments (3 ponds/treatment): Nile Tilapia alone (100% Nile Tilapia, monoculture group [MG]); 75% Nile Tilapia and 25% Thinlip Grey Mullet (polyculture group 1 [PG1]); 75% Nile Tilapia, 12.5% Thinlip Grey Mullet, and 12.5% Striped Mullet (PG2); and 75% Nile Tilapia and 25% Striped Mullet (PG3). Fish were fed a commercial diet containing 25% crude protein twice per day. The efficiency of feed utilization was determined in terms of feed conversion ratio (FCR; feed intake/weight gain). Polyculture group 3 had the best FCR, whereas the FCR results did not differ significantly among the MG, PG1, and PG2 treatments. In addition, PG3 had the highest total yield (3,350.3 kg/pond), followed in descending order by PG2 (3,234.4 kg/pond), PG1 (3,078.4 kg/pond), and MG (2,856.3 kg/pond). The PG3 treatment achieved the highest net financial return, followed by PG2, PG1, and MG. This study indicates that tilapia–mullet polyculture may improve the efficiency with which natural food resources are used within the system, resulting in better environmental quality, system sustainability, feed utilization, and net financial return.

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ribulus terrestris extract and 17α-methyltestosterone were added into the diets of red tilapia fry with an initial average weight of 0.02 ± 0.003g and an average length of 0.6 ± 0.012cm to study their effects on sex reversal and gonads histology. Two T. terrestris extract treatments (1 and 2g/kg diet); three hormonal treatments of 17α-methyltestosterone (30, 60 and 100 mg/kg diet) were used in this study and a control group, the study lasted 112 days. Results showed that T. terrestris extract and 17α-MT has a potential effect on directing gonadal sex differentiation of red tilapia towards males depending on the dose applied. The highest male percentage 90% was obtained by 60 mg 17α-MT /kg diet followed by 2g T. terrestris / kg diet (84.40%). Histological examination of the gonads showed a clear deterioration in their structure as a result of hormonal therapy, the intensity of which increased with an increase in the hormonal dose. The effect from using a high dose of T. terrestris was slight. It can be concluded that the addition of T. terrestris extract and 17α-MT to the ration of red tilapia hybrid fry directs the gonads of red tilapia towards males and negatively affects the structure of the gonads.

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