Jan Glogowski

Studies on the role of exogenous proteolytic enzymes in digestion processes in fish

Studies were carried out on the proteolytic activity of the fry of common carp, rainbow trout, grass carp, and whitefish, as well as on the activity of digestive organs of adult common carp and rainbow trout. Activity of exogenous enzymes in relation to endogenous ones was assessed on the basis of the proteolytic value of fish food and the activity of digestive organs. It was found that the share of proteolytic enzymes of natural food in the digestion process in fish was high. Beginning from a weight of 50–100 g for common carp and 10 g for rainbow trout, the relation between the daily enzymatic ration and the weight of fish indicates the cooperation of an approximately constant amount of exogenous enzymes.

Studies on the proteolytic enzymes of invertebrates constituting fish food

Studies were carried out on the proteolytic activity of trypsin and pepsin-like enzymes of invertebrates consituting fish food. Relations between proteolytic activity of enzymes, pH, and temperature were established.

A study of the application of proteolytic enzymes to fish food

Abstract A study was carried out to determine the effect of adding bovine trypsin to the diet of common carp fry. When added in the same and three times the quantity normally found in natural foods it increased the proteolytic activity by the same proportion. After 58 days of the experimental diet there was no deleterious effect on the survival of fish. Food utilization, stated in terms of feeding coefficient, apparent net protein utilization (NPU), protein efficiency ratio (PER) and NPU was from 1.63 to 1.79, 19.3 to 21.3, 1.32 to 1.46 and 46.0 to 50.5 respectively. The percentage composition of bond amino acid in all fish groups was found to be the same after the experiment. However, a considerable decrease in the total proteolytic activity in the hepatopancreas was observed for these fish which were given bovine trypsin in the diet. These results, with other recently published material suggest the possibility of a new approach to the study of the application of proteolytic enzymes to fish food.

Cryopreservation of Muskellunge and Yellow Perch Semen

Abstract Effect of four extenders on the success of cryopreservation of the semen of muskellunge Esox masquinongy and yellow perch Perca flavescens was tested. These extenders consisted of 0.45 M sucrose and were supplemented with either (1) 15% dimethyl sulfoxide (DMSO), (2) 15% DMSO and 10% hens egg yolk, (3) 15% dimethylacetamide (DMA), or (4) 15% DMA and 10% egg yolk. The use of extender with DMA alone yielded only about 7% muskellunge sperm fertilizing ability after cryopreservation. Supplementation of this extender with egg yolk produced a fertilization rate (36.6% of the control where fresh sperm was used) not significantly different from rates obtained with extenders containing DMSO. No significant differences were found among particular pools (consisting of semen from three different males per pool) of muskellunge semen used in this experiment. Fertilization rates of cryopreserved yellow perch semen (range, 69.6% to 77.3%) were not significantly different among all extenders tested. Cryopreserva...

Factors affecting motility characteristics and fertilizing ability of sea lamprey spermatozoa

Abstract This study was conducted to determine the basic motility characteristics of the spermatozoa (hereafter, sperm) of sea lampreys Petromyzon marinus using computer-assisted motility analysis. We determined the effects of NaCl, KCl, and pH on semen motility. We also tested the effects of time after activation and sterilization on sperm motility and fertilizing ability. Sperm motility was inhibited by high osmolality (80 mM NaCl or KCl). There were inverse relationships between the NaCl concentration and straight-line velocity (VSL; r 2 = 0.97, P < 0.01) and linearity (LIN; r 2 = 0.81, P < 0.05). The duration of sperm motility decreased with increases in pH. Positive linear relationships were obtained between pH and VSL (r 2 = 0.79, P < 0.01) and LIN (r 2 = 0.78, P < 0.01). Sperm motility decreased with time; a 50% decrease in motile cells was observed 4 min after activation; after 10 min, only 7% of the sperm were still motile. Fertilizing ability declined to 27% after a 2-min exposure and to 0.4% af...

Characterization of zebra mussel (Dreissena polymorpha) sperm motility: duration of movement, effects of cations, pH and gossypol

We have examined effects of time after activation, pH, sodium and potassium, and gossypol concentrations on sperm motility of zebra mussel (Dreissena polymorpha). Zebra mussel spermatozoa appeared to have remarkable viability in the fresh water in comparison with freshwater fish sperm. Duration of sperm motility in fresh water is possibly one of the longest among freshwater animals, since it was not significantly changed 3 h after incubation at room temperature (20 °C) or 24 h of incubation at ±0 °C. High osmotic pressure suppresses sperm motility and effects of sodium and potassium are similar. Spermatozoa were inactive at acid pH and became gradually motile when exposed to pH 6.0–9.0. Gossypol appeared to be a very potent spermicidal agent and inhibited motility. This compound also inhibited fertilization. We observed some differences in gossypol effects on spermatozoa between North American and European zebra mussels. These data on zebra mussel sperm biology may be useful for better handling of gametes under laboratory conditions.