Investigation on the effects of age and time of stripping on spermatocrit and duration of sperm motility in Oncorhynchus mykiss

The effects of three male age groups (2, 3 and 4 years old) and spawning season on total duration of sperm motility and spermatocrit in November, December, January and February were studied. We found the highest amount of spermatocrit in 2 ^(+) year males, in November (31.50 ±1.61) and the lowest amount of spermatocrit in the same age group was in February (25.11 ±0.9). The highest amount of spermatocrit in 3 years old fishes was spotted in November (21.42 ± 0.7), but at this age, there were no significant difference between the level of spermatocrit in January and February. In 4 years old fishes, the highest spermatocrit value was seen in November (25.11 ±0.77) and the lowest spermatocrit was in February (18.20 ±0.20), but again with no significant difference between the amount of spermatocrit in January and February. In 2 years males, the highest duration of sperm motility was in January (27.7 ± 1) and February (24.3 ±1.6), but there were no significant differences between January and February. In 3 years males, the longest duration of sperm motility was seen in January (29.9 ±1.1) which was highest and significantly different with other age groups. In 4 years old males, January was the month with the longest duration of sperm motility (29.42 ±0.4), which was also significantly different with other age groups. Duration of sperm motility in all male age groups was lowest in November, and we found it to be 24.86 ±0.9 at 2 ^ (+) years old males, 26.40 ±0.4) at 3 ^ (+) years old males and 26 ±0.32 at 4 ^ (+) years old males. The correlation between the amount of spermatocrit and duration of sperm motility in spawning season was negative and significant (r=0.642)

Effect of male age in rainbow trout (Oncorhynchus mykiss) on duration of sperm motility, spermatocrite and eyed egg rate production

Effects of three levels of Rainbow Trout male age (2+, 3+ and 4+ years old), on duration of sperm motility, spermatocrite and eyed egg rate in rainbow trout were studied in Kelardasht Fish Breeding Center. The sperm from 2+ year old males activated by water showed the shortest motility (24.86 sec) (P= 0.007), while those of the 3+ and 4+ years old revealed the longest sperm motility. No significant difference was found between sperm motility of the 3+ and 4+ males. The average spermatocrite in different age groups of male fish was significantly different. This was showed to be 32.66% in 2+ years and 2126 % in 3+ year's male age groups respectively. Eyed egg rate was highest in 2+ years age (86/82%), and was significantly different with the 3+ age group (P=0.02). The eyed egg rate of the 4+ age group was not significantly different with those of the 2+ and 3+ age groups

Effect of dietary protein and energy levels on rainbow trout (Oncorhynchus mykiss) reared in brackish water

A completely randomized design, with 3×3 factorial arrangement, was conducted to test various ratios of dietary protein to energy (P/E) for rainbow trout, reared in brackish water. Three crude protein levels (35, 40 and 45%) and three energy levels (370, 400 and 430 Kcal/100g) at each protein level were utilized. Semi-purified diet containing fish meal, casein and gelatin as the sources of protein and dextrin, starch and oil as the sources of energy was used. Each experimental diets was fed to triplicate groups of 20 fish with average weight of 81.5g, in nine 2000 lit flow through fiberglass tanks, each partitioned into three sectors. Average water temperature, dissolved oxygen, pH and EC were between 15±20C, 6.5-8.1 mg/L, 7.7-8.6 and 25400 µm/s, respectively. Fishes were fed for 84 days at a rate between 1.6-2% of body weight per day, in three equal amounts, adjusted bi- weekly. At each protein level, weight gain (WG%), average daily growth (ADG%), protein efficiency ratio (PER), apparent net protein utilization (ANPU%), specific growth rate (SGR) and condition factor (CF) increased, but feed conversion ratio (FCR) decreased with increasing energy level from 370 to 430 Kcal/100g. The highest growth performance was obtained by fishes fed by 35% protein, 430 Kcal/100g energy diet with P/E ratio of 81.4 mg protein/Kcal energy. Carcass fat and moisture were affected by dietary protein and energy levels, whereas, carcass protein and ash levels were similar between dietary treatments

Morphometric and meristic characteristics of Vimba vimba persa in Sefidrud River

During years 1999-2001, a series of sampling was carried out in Sefidrud River to study morphometric and meristic characteristics of Caspian Vimba. 149 specimens were collected and then necessary measurements were considered and following results were obtained: T.L= 171.2±31.6mm, W= 62.9±19.7g, age= 3.49±0.9 year, average number of scales on lateral line = 50.83±1.8, branched ray of dorsal and anal fins = 7.96±0.2 and 17.58±1.0 respectively. The mean morphometric measurements with respect to body standard length (%) were: head length 24.47±1.9, eye diameter 6.10±1.07, body maximum depth 26.17±1.4, dorsal fin height and length 20.22±1.5 and 10.96±0.8, anal fin height and length 12.66±0.8 and 18.17±1.5, pectoral fin length 18.17±1.2, ventral fin length 14.97±1.1, pecto-ventral fins distance 24.18±l.7 and ventral-anal distance 20.00±1.5 and pre-dorsal distance 52.21±1.7. Adults and juveniles showed difference in 2 meristic and 15 morphometric parameters. On the other hand, the adult males and females showed difference in 16 morphometric parameters (esp. body depth, lengths of dorsal, pectoral, pelvic and anal fins). Also, adult males have a series of fine epithelial tubercles on head and body and their color is darker with more reddish anal and ventral fins

Effects of stocking density on survival and growth indices of common carp (Cyprinus carpio)

The effects of social interactions on survival, growth indices and competitive behavior of common cam (Cyprinus carpio) at four stocking densities (350, 400, 450 and 500 fish per hectare) were investigated. A poly-culture of Chinese carps was implemented for 7 months in 12 Culture ponds each 10 hectares in size at Dikjeh area, Golestan province of Iran. Monthly biometrical characteristics such as total length, weight, and condition factor and growth rate were measured. The introduced common carp weighing on average 45g reached 705g after 7 months. With increase in common can) density up to 450 fish per hectare, growth indices including secondary weight, growth rate, SGR and fish biomass showed no significant differences (P>0.05), whereas 500 common carp individuals per hectare caused secondary weight, growth rate and SGR indices decrease significantly (P<0.05). At this density, fish biomass showed significant increase (P<0.05). Based on the results of this study, we conclude that common carp can be successfully cultured up to a density of 450 fish per hectare

Studying natural reproduction, spawning grounds and spawning period of Vimba vimba persa population in Sefid-roud river, Guilan Province in north Iran

To evaluate spawning status of Vimba vimba ,population in Sefid-roud river, 621 breeders, 1136 larvae, fries and fingerlings were caught in the river using beach seine, cast-net and electro-choker over the years 1999-2000. We found that the fish started spawning migration in March and continued it until July with its peak occurring between mid-April to late-May. Fork length was 116 - 208 mm (153.1 ± 17.95) in male specimens and 122 - 222 mm (173.5 ± 1 6.46) in females. Total body weight ranged 21.1-116.1g (52.92 ± 19.23) in males and 23.1 - 170.0 g (77.90 ± 22.88) in females. Males aged 2-6 years (3.53±0.86) and females aged 3-7 years (4.19±0.92) participated in the spawning with their maturity age being calculated as 2 and 3 years respectively. In all, breeders were composed of 51.82% males and 48.18% females with the ratio being significantly different only in May. Gonad weight was 1.13-7.92 g (Avg. 2.89±0.29) in males and 3.21-25.47g (Avg. 10.40±1.52) in females. We found the highest gonad weight for the fish in June and that the gonad weight in female breeders increased upwards of the estuary. Gonado-somatic index was 19-21% in 85.7% of the females and 3-8% in 95.5% of the males. Spawning of the species took place during day and night from late May to late June with its peak in May in water temperature ranging 18-29 degrees centigrade on pebble and gravel pounds from 25 to 75kms away from estuary. The Disaam tributary was distinguished as the major spawning area for the species

Identification of Pleuronectiformes species in the Persian Gulf (Khuzestan province) using morphometrics and meristics characteristics

This study was carried out to identify the different species of Pleuronectiformes order in the Khuzestan province waters (Persian Gulf) from March 2003 to June 2005. A Total of 671 specimens were collected by bottom trawl or from 7 main landings. The sampling period was seasonal. 36 main morphometric and meristic characteristics were measured. The results showed that 6 families of Soleidae, Cynoglossidae, Paralichtidae, Bothidae, Psettodidae and Citharidae are found in the studied area consist of 25 species of: Brachirus orentalis, Solea elongata, Monochirus lutenus, Parachirus marmoratus (family Soleidae); Cynoglossus ard, C. bilineatus, C. Puncticeps, C. durbanensis, C. lachneri (family Cynoglossidae); Pseudorombus annulatus, P. elevatus, P. arsius, P. malayanus, P. navaleusis, Paralichthodes algoensis, Poecilopstei javanicus (family Paralichtidae); Arnoglossus aspilos, A. arabicus, Engwrosopon grandisquama, Laeopes guentheri, L. natalensis, L. pectoralis, Psettina brevirictis (family Bothidae); Psettodes erumei (family Psettodidae) and Citharoides macrolepis (family Citharidae)

Spawning season, fecundity and Lm 50% of the Caspian Sea prawn (Palaemon adspersus) in the coastal waters of Guilan Province

The spawning season, fecundity and Lm50% of the Caspian Sea prawn (Palaemon adspersus) were investigated in the coastal waters of Guilan province. A monthly sampling was conducted using a bottom trawl with mesh size 3 mm in cod end in areas 0-5 and 5-10 meters deep during the year 2002. Mean total length, carapace length and weight of ovigerous female of Palaemon adspersus were 51.95±3.1 mm, 13.95+1.9mm and 2.742±0.58g (X ± S.D). Minimum and maximum total length of ovigerous specimens were 37 and 59.3mm with a weight 1.002 and 4.145 grams respectively. We found that the spawning season of Palaemon adspersus begins in April and ends in September with a peak in June. Mean fecundity of the species was 1994.5±506.6. The size at which 50% of females are mature was estimated to be 51.27mm total length

Evaluation of hydrogen peroxide effectiveness in fungal desinfection of Acipenser persicus eggs

Fungal infection during incubation of A cipenser persicus eggs claims high mortalities in the hatcheries each year. Malachite Green has been used for many years to disinfect eggs during incubation, but recent studies have shown that the compound might be toxic and potentially mutagenic. In addition, there are implications in the literature for the chemical to be teratogenic and tumor promoter in animals and humans. One of the best replacements for the chemical is Hydrogen Peroxide (H_2O_2) which has been categorized as a low priority regulation (LPR) drug by FDA. During a two year study, six experiments were carried out on the effectiveness of Malachite Green and Hydrogen Peroxide on the infected eggs of Persian sturgeon with fungi while keeping another group of the eggs as control in Yuschenkov incubators. The chemicals were applied to the eggs at a concentration of 750, 1000, 1500, 2000, 3000 and 9000 ml/l. Hatching rate and number of fungal colonies weight percentage of infected to that of healthy eggs were used to assess the usefulness of the chemicals in controling the infection. The results showed that eggs treated with 1000 and 1500 ml/l of H_20_2, compared to Malachite Green and other doses of the chemicals, had higher hatching rate, and were free from fungal infections. The separation and removal of the infected eggs was also easier when H_2O_2 was used. Hence, the chemical can be introduced to the sturgeon hatcheries as an appropriate anti-fungal agent

Preconcentration and extraction of copper(II) on activated carbon using ethyl-2-quinolyl-&beta; (p-carboxyphenyl hydrazone)dioxo propionate

Activated carbon modified method was used for the preconcentration and determination of copper content in real samples such as tap water, wastewater and a synthetic water sample by flame atomic absorption spectrometry. The copper(II) was adsorbed quantitatively on activated carbon due to its complexation with ethyl-2-quinolyl-β(p-carboxyphenyl hydrazone)dioxo propionate (EQCPDP). The adsorbed copper(II) ion on solid phase was eluted quantitatively by using nitric acid. The important parameters such as pH, amount of carrier, flow rate, amount of activated carbon and type and concentration of eluting agent for obtaining maximum recovery were optimized. The method at optimum conditions gives linear concentration range of 0.05-1.0 μg mL-1 of copper(II) with correlation coefficient of 0.9994 and the detection limit of 0.99 ng mL-1. The preconcentration leads to enrichment factor of 175 and break through volume of 1750 mL. The method has good tolerance limit of interfering ions and selectivity and it has been successfully applied for determination of copper content in real sample such as blood, wastewater and river sample. KEY WORDS: Copper(II), Solid phase extraction, Activated carbon, Flame atomic absorption spectrometry  Bull. Chem. Soc. Ethiop. 2008, 22(3), 331-338