OBSERVATION ON THE INDUCED SPAWNING PRACTICES IN THE HATCHERIES OF RAJSHAHI DISTRICT OF BANGLADESH
An investigation was conducted during the period from March to December 2009 to investigate the induced spawning practices in 22 hatcheries of 6 Upazilas of Rajshahi District of Bangladesh. It was observed that, 6 native fish species viz. rui ( Labeo rohita ), catla ( Catla catla ), mrigal ( Cirrhina mrigala ), calibaush ( Labeo calbasu ), bata ( Labeo bata ), gonia ( Labeo gonius ) and six exotic fish species such as silver carp ( Hypophthalmichthys moltrix ), bighead carp ( Aristichthys nobilis ), grass carp ( Ctenopharyngodon idella ), common carp ( Cyprinus carpio ), Thai pangus ( Pangasius sutchi ), rajputi ( Puntius gonionotus ) were used in the surveyed hatcheries for induced spawning purpose. The average length limit was 41.70±13.02 to 72.81±25.98 cm, average age limit was 1.96±0.75 to 3.08±0.90 years and average weight limit was 1.83±0.79 to 7.54±3.92 kg of the brood fish. Two types of hormone injections like PG (pituitary gland) and HCG (human chorionic gonadotropin) were used for induced spawning. The rate of 1st doses of injections of PG were from 1 to 4 mg/kg and HCG from 150 to 500 IU/kg and the rate of 2nd doses of injections of PG for native and exotic species were from 4 to 8 mg/kg and 4 to 10 mg/kg respectively. The incubation period and hatching rate in different fish species varied from 10 to 72 hours and 55% to 80%, respectively. DOI: http://dx.doi.org/10.3329/jles.v6i0.9723 JLES 2011 6: 65-68
Gonadotropic Hormone Treatment of Rainbow Trout (Salmo gairdneri): Plasma Hormone Profile Following a Single Injection
Immature rainbow trout (Salmo gairdneri) were treated with salmon gonadotropic hormone to determine the presence of this hormone in circulation, to describe the plasma profile with time after exogenous hormone treatment, and to determine the difference in plasma gonadotropin levels resulting from treatment with two different hormone doses. The effect of three selected temperatures on the plasma hormone profile was also studied. The plasma concentration of the injected hormone following a low dose (0.02 μg/g) and a high dose (0.2μg/g) suggested that plasma hormone levels were directly related to the hormone quantity injected. For fish maintained at 6 C, plasma gonadotropin values declined over a period of 7 days reaching low but detectable levels. Lower plasma gonadotropin profiles were observed for fish held at 6 and 15 compared with fish at 2 C ambient temperature. These data suggest the plasma gonadotropin levels and ambient temperature are related in an inverse manner.
The measuriment of ferromagnets magnetic characteristics using Labview software
The digital method of measurement and registration of dynamic loops hysteresis family of magneto-soft materials where, along with known analogues from electro-technical steel, magnetic materials with considerably smaller specific magnetic losses such as amorphous alloys on the basis of iron, is offered. Tests of magnetic properties of materials are carried out on the base of the hardware-software measuring complex in which along with the standard established electric equipment and USB oscillograph for realization of a digital method, the software for the personal computer developed in the environment of visual programming of Borland Delphi 7.0, connected through the ActieveX technology with the Labview 7.0 environment, is applied. The software allows carrying out input of basic data concerning geometry of prototypes of cores from magnetic materials and numbers of rounds of the magnetizing and measuring windings located on their surface. Experimental data on voltage at measuring winding terminals are processed by means of the virtual integrator in a Labview package. The developed software provides the possibility of saving the obtained hysteresis loop in the form of a text file, and creation of the hysteresis loops family on the virtual oscillograph screen.