Abstract: Rainbow trout (Oncorhynchus mykiss) and Brown trout (Salmo trutta fario) are the two species of trout which were once introduced by British in waters of Kashmir has well adapted to favorable climatic conditions. Cold water fisheries are one of the emerging sectors in Kashmir valley and trout holds an important place Jammu and Kashmir fisheries. Realizing the immense potential of trout culture in Kashmir region, the state fisheries department started privatizing trout culture under the centrally funded scheme of RKVY in which they provide 80 percent subsidy for raceway construction and supply of feed and seed for the first year since 2009-10 and at present there are 362 private trout farms. To cater the growing demand for trout in the valley, it is important to understand the bottlenecks faced in the propagation of trout culture. Value chain analysis provides a generic framework to understand the various activities and processes, mapping and studying linkages is first step that needs to be done in any value chain analysis. In Kashmir, it is found that trout hatcheries play a crucial role in insuring the continuous supply of trout seed in valley. Feed is most limiting factor in trout culture and the farmer has to incur high cost in payment and in the transportation of feed from the feed mill to farm. Lack of aqua clinic in the Kashmir valley needs to be addressed. Brood stock maintenance, breeding and seed production, technical assistance to private farmer, extension services have to be strengthened and there is need to development healthier environment for new entrepreneurs. It was found that trout farmers do not avail credit facility as there is no well define credit scheme for fisheries in the state. The study showed weak institutional linkages. Research and development should focus more on applied science rather than basic science.
Abstract: Landfill waste is a common problem as it has an
economic and environmental impact even if it is closed. Landfill
waste contains a high density of various persistent compounds such
as heavy metals, organic and inorganic materials. As persistent
compounds are slowly-degradable or even non-degradable in the
environment, they often produce sublethal or even lethal effects on
aquatic organisms. The aims of the present study were to estimate
sublethal effects of the Kairiai landfill (WGS: 55°55‘46.74“,
23°23‘28.4“) leachate on the locomotor activity of rainbow trout
Oncorhynchus mykiss juveniles using the original system package
developed in our laboratory for automated monitoring, recording and
analysis of aquatic organisms’ activity, and to determine patterns of
fish behavioral response to sublethal effects of leachate. Four
different concentrations of leachate were chosen: 0.125; 0.25; 0.5 and
1.0 mL/L (0.0025; 0.005; 0.01 and 0.002 as part of 96-hour LC50,
respectively). Locomotor activity was measured after 5, 10 and 30
minutes of exposure during 1-minute test-periods of each fish (7 fish
per treatment). The threshold-effect-concentration amounted to 0.18
mL/L (0.0036 parts of 96-hour LC50). This concentration was found
to be even 2.8-fold lower than the concentration generally assumed to
be “safe” for fish. At higher concentrations, the landfill leachate
solution elicited behavioral response of test fish to sublethal levels of
pollutants. The ability of the rainbow trout to detect and avoid
contaminants occurred after 5 minutes of exposure. The intensity of
locomotor activity reached a peak within 10 minutes, evidently
decreasing after 30 minutes. This could be explained by the
physiological and biochemical adaptation of fish to altered
environmental conditions. It has been established that the locomotor
activity of juvenile trout depends on leachate concentration and
exposure duration. Modeling of these parameters showed that the
activity of juveniles increased at higher leachate concentrations, but
slightly decreased with the increasing exposure duration. Experiment
results confirm that the behavior of rainbow trout juveniles is a
sensitive and rapid biomarker that can be used in combination with
the system for fish behavior monitoring, registration and analysis to
determine sublethal concentrations of pollutants in ambient water.
Further research should be focused on software improvement aimed
to include more parameters of aquatic organisms’ behavior and to
investigate the most rapid and appropriate behavioral responses in
different species. In practice, this study could be the basis for the
development and creation of biological early-warning systems
(BEWS).
Abstract: The present study was done to evaluate the presence
of tetracycline resistance genes in Lactococcus garvieae isolated
from cultured rainbow trout, West Iran. The isolates were examined
for antimicrobial resistance using disc diffusion method. Of the 49
strains tested, 19 were resistant to tetracycline (38.7%), 32 to
enrofloxacin (65.3%), 21 to erythromycin (42.8%), 20 to
chloramphenicol and trimetoprim-sulfamethoxazole (40.8%). The
strains were then characterized for their genotypic resistance profiles.
The results revealed that all 49 isolates contained at least one of the
tetracycline resistance genes. Tet (A) was found in 89.4% of
tetracycline resistant isolates and the frequency of other gene were as
follows: tet (E) 42.1%, tet (B) 47.3%, tet (D) 15.7%, tet (L) 26.3%,
tet (K) 52.6%, tet (G) 36.8%, tet (34) 21%, tet (S) 63.1%, tet (C)
57.8%, tet (M) 73.6%, tet (O) 42.1%. The results revealed high levels
of antibiotic resistance in L. garvieae strains which is a potential
danger for trout culture as well as for public health.
Abstract: The aim of present study was to monitor the presence
of Trichodina sp. in Rainbow trout, Oncorhynchus mykiss collected
from various fish farms in the western provinces of Iran during
January, 2013- January, 2014. Out of 675 sampled fish 335, (49.16%)
were infested with Trichodina. The highest prevalence was observed
in the spring and winter followed by autumn and summer. In general,
the intensity of infection was low except in cases where outbreaks of
Trichodiniasis endangered the survival of fish in some ponds. In light
infestation Trichodina is usually present on gills, fins and skin of
apparently healthy fish. Clinical signs of Trichodiniasis only appear
on fish with heavy infections and cases of moderate ones that are
usually exposed to one or more stress factors including, rough
handling during transportation from ponds, overcrowdness,
malnutrition, high of free ammonia and low of oxygen concentration.
Clinical signs of Trichodiniasis in sampled fish were sluggish
movement, loss of appetite, black coloration, necrosis and ulcer on
different parts of the body, detached scales and excessive
accumulation of mucous in gill pouches. The most obvious
histopathological changes in diseased fish were sloughing of the
epidermal layer, aggregation of leucocytes and melanine-carrying
cells (between the dermis and hypodermis) and proliferative changes
including hyperplasia and hypertrophy of the epithelial lining cells of
gill filaments which resulted in fusion of secondary lamellae. Control
of Trichodiniasis, has been achieved by formalin bath treatment at a
concentration of 250 ppm for one hour.
Abstract: Aldehyde oxidase is molybdo-flavoenzyme involved in the oxidation of hundreds of endogenous and exogenous and N-heterocyclic compounds and environmental pollutants. Uncharged N-heterocyclic aromatic compounds such phenanthridine are commonly distributed pollutants in soil, air, sediments, surface water and groundwater, and in animal and plant tissues. Phenanthridine as uncharged N-heterocyclic aromatic compound was incubated with partially purified aldehyde oxidase from rainbow trout fish liver. Reversed-phase HLPC method was used to separate the oxidation products from phenanthridine and the metabolite was identified. The 6(5H)-phenanthridinone was identified the major metabolite by partially purified aldehyde oxidase from fish liver. Kinetic constant for the oxidation reactions were determined spectrophotometrically and showed that this substrate has a good affinity (Km = 78 ± 7.6µM) for hepatic aldehyde oxidase, will be a significant pathway. This study confirms that partially purified aldehyde oxidase from fish liver is indeed the enzyme responsible for the in vitro production 6(5H)-phenanthridinone metabolite as it is a major metabolite by mammalian aldehyde oxidase, coupled with a relatively high oxidation rate (0.77± 0.03 nmol/min/mg protein). In addition, the kinetic parameters of hepatic fish aldehyde oxidase towards the phenanthridine substrate indicate that in vitro biotransformation by hepatic fish aldehyde oxidase will be a significant pathway. This study confirms that partially purified aldehyde oxidase from fish liver is indeed the enzyme responsible for the in vitro production 6(5H)-phenanthridinone metabolite as it is a major metabolite by mammalian aldehyde oxidase.
Abstract: In a 10-week (May – August, 2008) Phase I trial, 840, 1+ rainbow trout, Oncorhynchus mykiss, received a commercial oral immunomodulator, Fin Immune™, at four different dosages (0, 10, 20 and 30 mg g-1) to evaluate immune response and growth. The overall objective of was to determine an optimal dosage of this product for rainbow trout that provides enhanced immunity with maximal growth and health. Biweekly blood samples were taken from 10 randomly selected fish in each tank (30 samples per treatment) to evaluate the duration of enhanced immunity conferred by Fin-Immune™. The immunological assessment included serum white blood cell (lymphocyte, neutrophil) densities and blood hematocrit (packed cell volume %). Of these three variables, only lymphocyte density increased significantly among trout fed Fin- Immune™ at 20 and 30 mg g-1 which peaked at week 6. At week 7, all trout were switched to regular feed (lacking Fin-Immune™) and by week 10, lymphocyte levels decreased among all levels but were still greater than at week 0. There was growth impairment at the highest dose of Fin-Immune™ tested (30 mg g-1) which can be associated with a physiological compensatory mechanism due to a dose-specific threshold level. Thus, our main objective of this Phase I study was achieved, the 20 mg g-1 dose of Fin-Immune™ should be the most efficacious (of those we tested) to use for a Phase II disease challenge trial.
Abstract: Rainbow trout homogametic males, (XX or YY sex genotype), can be obtained, respectively, through masculinisation of genetic females or induced androgenesis. Aim of this study was to compare reproductive potential of neo-males (XX) and super-males (YY) with heterogametic males (XY). We measured spermatozoa motility parameters, sperm concentration, osmolality and characterized protein profiles in samples of stripped and testicular sperm obtained from XY and YY males, and testicular sperm of XX males. The motile spermatozoa, as measured by both subjective method and CASA, showed no differences between testicular sperm of XX males and stripped sperm of XY and YY males whereas testicular sperm of XY and YY males had significantly lower sperm motility. Result of protein densitometry showed similarities in protein profile between seminal plasma of XY and YY males and testicular fluids of XX males. Testis of XX males showed specific histological structures of cysts consists hypertrophied Sertoli cells.
Abstract: In this study Vitaton (an organic supplement which
contains fermentative β-carotene) and synthetic astaxanthin
(CAROPHYLL® Pink) were evaluated as pro-growth factors in
Rainbow trout diet. An 8 week feeding trial was conducted to
determine the effects of Vitaton versus astaxanthin on rearing factors,
survival rate and visual flesh color of Rainbow trout
(Oncorhnchynchus mykiss) with initial weight of 196±5. Four
practical diets were formulated to contain 50 and 80 (ppm) of β-
carotene and astaxanthin and also a control diet was prepared without
any pigment. Each diet was fed to triplicate groups of fish rearing in
fresh water. Fish were fed twice daily. The water temperature
fluctuated from 12 to 15 (C˚) and also dissolved oxygen content was
between 7 to 7.5 (mg/lit) during the experimental period. At the end
of the experiment, growth and food utilization parameters and
survival rate were unaffected by dietary treatments (p>0.05). Also,
there was no significant difference between carcass yield within
treatments (p>0.05). No significant difference recognized between
visual flesh color (SalmoFan score) of fish fed Vitaton-containing
diets. On the contrary, feeding on diets containing 50 and 80 (ppm)
of astaxanthin, increased SalmoFan score (flesh astaxanthin
concentration) from