Ionic regulation ability in Rutilus frisii kutum fingerlings during sea water adaptation.

Experiments were conducted to determine the effects of weight on the ionic regulation ability of reared Rutilus frisii kutum fingerlings during adaptation to the seawater and downstream migration. Accordingly, the ionic regulation ability of Cl-, K+, Na+ and Mg2+ in kutum fingerlings with weights of 1, 3, 5 and 7 g in three different salinities, that is 13‰ (the Caspian Sea salinity), 7‰ (estuarine area) and fresh water (as control, 0.3-0.5‰), were assessed. The blood samples were provided before being transferred as control (fresh water) and during adaptation to the sea and estuary water in a period of up to 336 h by a pooling method. The measurements of ions were carried out for blood serum Na+ and K+ and alsoplasma Cl-1 and Mg2+ by photometric methods. This investigation showed that ionic regulatory ability of kutum fingerlings depends on their weights. Results of ionic changes during the duration of 336 h (14 days) proved that unlike kutum fingerling with weights of 3, 5 and 7 g, the ionic regulation system in 1 g fingerlings were not able to expel excess ions. Further 1 g kutum were not physiologically ready (smolt) for downstream migration

Status and potential of herbal applications in aquaculture: a review

Disease are recognized as one of the major constraint to sustainable animal production which can cause significant economic loss especially in aquaculture. Various chemotherapeutic agents have been traditionally used in the treatment and prevention of diseases in farmed fish but they are not recommended since improper and continuous use of antibiotics may lead to potential development of antibiotic resistant bacteria, environmental pollution and accumulation of toxic residues in fish. Therefore, scientists have intensified efforts to exploit natural products such as herbs in developing alternative dietary supplements that enhance growth performance, and health and immune system of cultured fish, as these products are inexpensive, safer, effective, and can be easily prepared and are biodegradable. This review discusses the findings from different studies related to the in-vitro and in-vivo applications of herbs and plant extracts or their combinations, in relation to appetite stimulator, growth promoter, antimicrobial, antiparasitic, antioxidant and immunostimulation in fish

Growth performance and disease resistance towards Aeromonas hydrophila in Hemibagrus nemurus (Valenciennes, 1840) fingerlings through probiotic feeding

A study was carried out to evaluate the probiotic activity of Bacillus subtilis G1 isolated from fermented pickles in growth performance and disease resistance of Hemibagrus nemurus fingerlings at Universiti Putra Malaysia. The probiotic was mixed in feed at doses of 0 (C, control), 3 x 10^9 (T1) 3 x 10^7 (T2) and 3 x 10^5 (T3) cfu g^-1 and fed to the catfish fingerlings for nine weeks. Results showed that catfish fed a diet containing 10^7 cfu g^-1 B. subtilis G1 had significantly higher percent weight gain (248.69 ± 3.31%), and better food conversion ratio (1.68 ± 0.03), than those of other treatments. Inhibitory activity of the probiotic B. subtilis G1 against fish pathogens Aeromonas hydrophila and Streptococcus agalactiae was evaluated by well diffusion agar method. Inhibition zones measured showed A. hydrophila and S. agalactiae were 16.13 ± 0.91 mm and 17.5 ± 1.84 mm, respectively, indicating strong inhibitory activity against the pathogens. Three weeks after the feeding trial, the fingerlings were challenged with 0.1 ml containing 10^6 cfu ml^-1 of A. hydrophila by intra-peritoneal injection. After 14 days, the mortality rate of catfish was significantly lower in group T1 (30 ± 5.8%) compared to the control (C) group (56.7 ± 3.3%). The findings of this study proved that administration of B. subtilis G1 can improve growth and disease resistance in catfish

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