IJA Volume 55, Issue 3, 2003
Permanent URI for this collection
Browse
Recent Submissions
1 - 8 of 8
-
ItemHatchery And Growth Performance of Two Trout Pure Breeds, Salvelinus Alpinus And Salmo Trutta Fario, And Their Hybrid(Israeli Journal of Aquaculture - BAMIGDEH, 2003)An allelic cross between Salmo trutta fario and Salvelinus alpinus was carried out under con- trolled hatchery conditions. Survival to the eyed stage was significantly lower for the hybrid than for both purebreds. There were significant differences in survival in the eyed and yolk sac stages and from fertilization to the first feeding (p<0.05) between the hybrid and the purebreds, while the differences between the purebreds were not significant (p>0.05). The hybrid did not display heterosis with respect to any hatchery property. During the first 45 days of nursing, there were significant differences between the purebreds and the hybrid in terms of weight gain, survival, feed conversion ratio and specific growth rate (p<0.05) with no significant differences between the purebreds (p>0.05). The hybrid was slightly heterotic (+1.69) with respect to survival how- ever no heterosis was observed in any other property to the first feeding stage.
-
ItemReplacing Fish Meal In Rainbow Trout (Oncorhynchus MyKiss) Diets(Israeli Journal of Aquaculture - BAMIGDEH, 2003)The effects of Ohio State University (OSU) meal (a mixture of blood meal, meat and bone meal, poultry by-products and feather meal), as partial or total replacement of fish meal was investi- gated. Thirty-two fish tanks, each containing 30 rainbow trout (initial mean weight 1.93 g), were fed one of 10 diets (the control had only two replicates) containing a different quantity of OSU meal for 14 weeks. The trout fed the diets containing 20% or 40% OSU meal grew similarly to the trout fed the fish meal based diet. Total replacement of the fish meal caused a significant reduction in growth (p<0.05) only at the 47% protein level and not at the 36%. The results of this study suggest that diets containing up to 75% OSU meal and 25% fish meal are sufficient for good growth in rainbow trout fry.
-
ItemCryopreservation Of Rainbow Trout (Oncorhynchus Mykiss) Semen(Israeli Journal of Aquaculture - BAMIGDEH, 2003)Rainbow trout semen was diluted in one of three extenders (1:3 v/v) containing egg yolk (7-10%) and 10% DMSO as cryoprotectants. The diluted semen was packaged in 0.5 ml straws and frozen in liquid nitrogen (LN2) vapor. For thawing, the straws were immersed in a water bath for 30 sec at 30°C. The best post-thaw motility and fertilization results, 56.67±5.77% and 80.5±16.01% respectively, were obtained when a glucose based extender was used.
-
ItemFeeding Frequency And Feed Intake In The African Catfish Clarias Gariepinus (Burchell 1822)(Israeli Journal of Aquaculture - BAMIGDEH, 2003)Triplicate groups of subadult catfish (Clarias gariepinus; 102.18±30.48 g) were fed a purified diet to satiation twice or three times a day during the daylight hours for 26 days. Fish fed twice a day consumed 1.42±0.49% of their body weight per day. Those fed three times a day consumed 1.27±0.27%. The fish fed twice a day exhibited better growth and food conversion. Despite the use of purified diets, performance indices for the group fed twice per day were good, compared to previously reported data. The specific growth rate was 1.24±0.08%, the weight gain was 38.51±2.96% and the food conversion ratio was 0.72±0.13.
-
ItemGrowth And Production In Long-Line Cultivated Mediterranean Mussel (Mytilus Galloprovincialis) In Sinop, Black Sea(Israeli Journal of Aquaculture - BAMIGDEH, 2003)One-year rope-grown mussels (Mytilus galloprovincialis Lam.) with a mean length of 37.6±0.52 mm and live weight of 5.02±0.28 g were collected from fish farm mooring ropes and cultured in cotton or nylon socks in a long-line system in Sinop, Black Sea. The growth of the mussels, water temperature, salinity, chlorophyll a, seston and particulate organic matter were monitored from July 1997 for eleven months. Shell length and live weight were high from May to October when the temperature was 13oC-25oC. Growth decreased during late autumn and winter due to the low temperature and food availability. A significant and positive relationship was found between particulate organic matter, shell growth and live weight. At the end of the experiment, shell length reached 59.89±0.93 mm in the cotton socks and 57.81±0.88 mm in the nylon socks, while live weight reached 19.42±0.91 g in the cotton socks and 16.89±0.76 g in the nylon. Harvestable production was lower in the cotton (4.1 kg/m) than in the nylon socks (8.7 kg/m). Meat yield was high during spring and early summer and significantly and positively correlated with chlorophyll a, particulate organic matter and seston. In the light of these results, recom- mendations for mussel culture in the long-line system are given.
-
ItemEffects Of Meal Frequency On Growth And Reproduction In The Ornamental Red Swordtail, Xiphophorus Helleri(Israeli Journal of Aquaculture - BAMIGDEH, 2003)Experiments were performed to investigate the influence of meal frequency on growth, gonad weight and fertility in an ornamental fish, the red swordtail Xiphophorus helleri. Five groups of uniform-sized 30-day juveniles (0.04±0.01 g, 13.10±0.61 mm) were fed either one meal in 3 days (1/3), one meal in 2 days (1/2), one meal a day (1/1), two meals a day (2/1) or three meals a day (3/1) for 210 days. Group 3/1 had the highest mean body weight throughout the experiment, fol- lowed successively by groups 2/1, 1/1, 1/2 and 1/3. The growth rate was higher in all groups before breeding began and drastically declined afterwards; the significant reduction might have been due to the diversion of assimilated food energy to fry production. The gonad weight and gonadosomatic index (GSI) increased with the increase in meal frequency and as the rearing period progressed. Fish in groups 1/1, 2/1 and 3/1 began to develop gonads on day 42 and reached the breeding stage on day 70; fish in 1/2 and 1/3 began to develop gonads on days 70 and 98 and reached the breeding stage on days 98 and 112, respectively. The increase in meal frequency significantly reduced the interbrood interval and fertility. Fish in group 3/1 produced the highest number of fry (704). Those in groups 2/1, 1/1, 1/2 and 1/3 released 450, 372, 70 and 8 fry, respectively. Groups 3/1, 2/1, 1/1, 1/2 and 1/3 bred four, three, three, two and one times, respectively. Based on the present study, three meals a day is optimum for X. helleri growth and reproduction in a culture system.
-
ItemInheritance Of The White-Red (Kohaku) Color Complex In Ornamental (Koi) Carp (Cyprinus Caprio L.)(Israeli Journal of Aquaculture - BAMIGDEH, 2003)Color variability was investigated in three normal (amphimictic) and three meiotic gynogenetic progenies obtained from white-red (kohaku, according to Japanese classification) koi parents. All the amphimictic and gynogenetic progenies consisted of three color types – white, white-red and red. The ratio of colors depended on the relative coverage by red patches in the kohaku parents. The lowest percentage of red fish and highest proportion of white fish were recorded in progeny obtained from kohaku parents with relatively weak development of the red color. The percent coverage by red patches was measured in a sample of thirty or sixty white-red fish from each amphimictic progeny and the distribution of color classes within the sample was determined. The distribution of the sample, together with the white:white-red:red ratio in the total progeny, was used to estimate the color class distribution in the entire progeny (including the solid white and solid red individuals). In two of the amphimictic progenies, the fish clearly divided into two groups: non-red (solid white and white-red) and solid red fish. Appearance of these groups might be explained by the existence of some major color-determining gene(s), which determine(s) the background color (either white or red) of the individual fish. It is also suggested that the devel- opment of red patches in fish with a white body background is controlled by many genes with alleles that either maintain the white color or induce the appearance of red patches.
-
ItemEffects of Chloramine-T And CuSO4 On Enzyme Activity Of Glucose 6-Phosphate Dehydrogenase From Rainbow Trout (Oncorhynchus Myskiss) Erythrocytes In Vitro An In Vivo(Israeli Journal of Aquaculture - BAMIGDEH, 2003)Traditional treatments of parasitic and bacterial diseases are based on chemotherapeutic com- pounds such as chloramine-T and CuSO4. Although many compounds are used in fish treat- ments, their undesirable effects are not known. In this study, glucose 6-phosphate dehydroge- nase (G6PD) was purified from rainbow trout (Oncorhynchus mykiss) erythrocytes by hemolysate preparation, ammonium sulfate precipitation and 2', 5'-ADP Sepharose 4B affinity gel chromatography in a single day. The enzyme, with a specific activity of 14.51 EU/mg protein, was purified 906.8-fold with a yield of 70.38%. To check the purity of the enzyme, SDS poly- acrylamide gel electrophoresis was performed, which showed a single band. The effects of chlo- ramine-T and copper sulfate (CuSO4) on the G6PD were investigated in vitro. Chloramine-T and CuSO4 had inhibitory effects on the enzyme. I50 values of the chemotherapeutic compounds were determined by plotting percent activity and Ki values, and types of inhibition were deter- mined for each compound by means of Lineweaver-Burk graphs. In vivo studies showed that G6PD in rainbow trout erythrocytes was significantly inhibited by CuSO4 in one hour but not inhibited by chloramine-T.