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An experiment was conducted to evaluate the growth performance of Nile tilapia fed with supplemental feed (25% crude protein) at 50% satiation. Juvenile Nile tilapia (average weight 6.4 g) were stocked in an earthen pond at 2.4 fish m⁻² . The pond was fertilized twice weekly with a mixture of superphosphate and urea fertilizer (68 kg ha 1⁻¹). The annual fish yield was 6880 kg ha⁻¹. The mean weight of harvested fish ranged from 110 to 250 g. The food conversion ratio (FCR) was 0.82, the average daily weight gain (ADG) was 0.9 g d⁻¹ and the specific growth rate was 1.55 % d⁻¹. This study demonstrated that 50% satiation feeding is an effective feeding rate for improving the production of Nile tilapia cultured in a fertilized, freshwater earthen pond.
The rearing of carp K2-3 in polyculture with a grass- carp, silver carp and European catfish was carried out within 1995- 1997, in six (1995-1996) or in seven (in 1997) variants of ponds differed in stocking densities as well as in kind of feed fed. The objective of the present paper was to verify if the change of harvest date from September into November can affect the quality of discharged waters. Estimation of discharged water quality was made on the basis of following chemical factors: dissolved oxygen, water pH, total suspended matter, chemical oxygen demand CODMn, ammonia nitrogen, nitrate nitrogen, nitrite nitrogen and phosphates. The change of harvest date for 40 days improved markedly the quality of discharged water.
Background. In Indian carp culture, a 1 : 1 mixture of rice bran and oil cake is traditionally used as feed in powder form; it is nutritionally inadequate and also a large part of it goes unutilized as the fish cannot feed on the powder effectively. With a view to improve its nutritional quality and reduce the wastage, the mixture was supplemented with soya and maize flours and converted into pellet form. The performance of the supplemented diets was evaluated by feeding them to catla, Catla catla, one of the popular Indian major carps. Materials and methods. Two test diets were formulated supplementing the feed mixture with soya flour (10% and 20%) and maize flour (39%), replacing equal quantities of rice bran and oilcake. These diets along with the control diet were fed to triplicate groups of catla fry maintained in outdoor cement tanks for 120 days. Results. The test diets enhanced growth and net fish production significantly (P < 0.05). This resulted in higher economic returns under the two test treatments. Survival of fish ranged from 74% to 76%. Carcass of fish receiving the test diets had significantly (P < 0.05) higher lipid and lower moisture levels. Digestive enzyme activity was affected positively (P < 0.05) by the test diets. Conclusion. Replacing rice bran and oilcake from the traditional feed mixture with soya and maize flours proved economically viable.
The present studies were concentration of ammonia, nitrite, nitrate, dissolved oxygen, temperature, salinity and pH. For seven physicochemical parameters were determined in marine water samples along with marine ornamental fish water sources from CAS in marine biology laboratory conditions at Parangipettai. Water sample have been studied at a marine water sources. The study concentrations of parameters like ammonia, nitrite, nitrate, dissolved oxygen, temperature, salinity, and pH. And physicochemical parameters have been calculated. The data showed the difference of the investigated parameters in samples as follows; Concentration of water quality parameters like ammonia was maximum level above 1.158 μmol¯1, nitrite was ranging from 0.811 to 0.922 μmol¯1, nitrate was range maximum level above 4.84 μmol¯1, dissolved oxygen content was maximum level above 2.4 mg¯1, temperature was ranging from 32.3 to 100 °C, salinity values ranging from 0 to 36ppt and pH was ranging from 6.5 to 8.0. During the study period of from July 2013 to June 2014 we investigated concentration of seven physicochemical parameters value Marine water samples with cultured fish species in presence of water from CAS in Marine Biology laboratory Annamalai University at Parangipettai.
Monitoring the condition of fish and protecting them from diseases are two of the most important aspects of prevention in intensive fish culture. Nonspecific cellular and humoral defense mechanisms were studied for the first time in pikeperch (Sander lucioperca) grown in an intensive system of culture using two sizes of fish weighing approximately 50 g and 500 g. The respiratory burst activity and potential killing activity of blood phagocytes and pronephric macrophages were measured in each group. The proliferative response of lymphocytes stimulated by mitogen ConA and LPS was also examined in the two groups of fish. The lysozyme and ceruloplasmine activities in the plasma and the total protein with Ig levels in the serum were also determined. These results will be used in controlling the influence of diets and xenobiotics on nonspecific cellular and humoral defense mechanisms and for infectious disease prevention in pikeperch raised in different systems of culture.
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