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Ahmad Farhadi, Mohammad Ali Nematollahi

PhD student and assistant professor, department of Fisheries, University of Tehran Abstract

Larval rearing is main barrier in spiny lobsters -most highly commercial species of decapods aquaculture. Unfortunately, little is known about natural ecology and feeding of spiny lobster larvae and there is a very few success on larval rearing. Meanwhile there is consistently high demand and price for this species with very significant decrease in wild fisheries landing. This paper will review the global status of spiny lobster including aquaculture status and development requirements of spiny lobster larvae rearing with emphasis on Panulirus homarus.

Key words: Spiny lobster, larvae, aquaculture

Introduction

Palinuridae family has long living transparent larvae which widely dispersed in open waters weeks to several months. It includes 3 main stages of prelarvae (naupliosoma)), larval phase (phyllosoma) and post-larval phase (puerulus) (Phillips et al., 2007). Larval duration for Panulirus homarus species takes around б-9 months. Many aspect of larval ecology of Panulirus sp still remains unknown.

Status of world spiny lobsters fisheries and aquaculture

Figure1: Decrease in Panulirus homarus landing in Iran (Red line) and global (blue line)

Spiny lobsters are among most valuable fisheries species around the world. These crustaceans species has importance ecologic role in marine ecosystems as well (ref). But many aspects of its life history including population structure and connectivity pattern in many species are still unknown (Phillips and Melville-Smith, 200б). Panulirus homarus is an indo-East Pacific resident that occurs in Iranian south-east coasts. The fisheries landing of Panulirus homarus has been decrease during last decade (FAO, 2009) especially in Iranian coast of Oman sea (ref) and Arab sea coasts in sultanate of Oman.

The propagation and aquaculture rearing of these species have been increased during past decades in south East Asian countries such as Phillippines, Indopnesia, India, Thailand, Micronesia and Vietnam. Aquaculture production value of spiny lobster has been reached 65rnillion USD in 200б only in Vietnam. But the larval resource is completely depended on wild seed and makes this industry risky as access to good quality seed from wild is not granted. Pnaulirus ornatus, P.cygnus, P.japonicus and P.homarus are the main specis in spiny lobster farming because of shorter larval period in comparison with other Panulirus sp . P.homarus has become an interest for aquaculture because of its high price, marketability. Despite this because of some bottlenecks in larvae rearing the aquaculture of spiny lobsters are in their beginning.

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Aquaculture production of P.homorus in Vietnam,

Figure2: aquaculture production status of Panulirus homarus in Vietnam as first producer stress larval culture development needs.

Main barrier in larval culture includes:

- Long larval period

- Frequency of bacterial disease

- Aggregation caused by negative photoreaction

- Lack of information on feeding condition and diet items

- Lack of ecological information What should be done?

Steady growth of spiny lobster aquaculture can be accelerated by using different approach to overcome a bow mentioned barriers in larval culture. Recently some efforts have been done on designing specific tanks for phyllosoma culture of P.japonicus. These photoreaction solving tanks could be useful in others Panulirus sp larval cultures such as P.homarus (scalloped spiny lobster). New robust techniques such as molecular biology and genetics can help dispel the noted problems facing larvae culture of these precious aquaculture candidates.

Genetic in larval rearing improvements

- Larval identification by genetic techniques will very useful in using wild puerulus in lobster aquaculture

- Identification of prey item to improve nutrition. A study with next

generation technology has been revealed food items of Panulirus cygnus successfully (O'Rorke et al., 2012). This approach can be applied in P.homarus as well.

- Selective breeding and genetic modification possibly via shortening the larval period as long larval period is one of the main hinders of phyllosoma culture

- come over with frequent occurrence of bacterial disease as another important barrier of larvae culture of the species

- Identification of different geographic races, their cross breeding and application in using of natural seeds.

- Using genetic techniques in identification of larval development ontogeny main enzymes involved in early feeding.

- Using genetic in molecular biotechnology in pathogen free seed in future to control the disease as it has been done in shrimp.

Conclusion

Regarding few both practical efforts and researches started on the different biological aspects of spiny lobsters, larval rearing for species such as P.homarus has promising future prospects. Because of decrease in global catch spiny lobster, its aquaculture development is urgent to support global market. Sea-cage culture of spiny lobsters such as scalloped spiny lobster would likely be more feasible only if seed supply came from hatchery production and if access was granted to use appropriate site. Revealing unknown aspect of larvae biology will help both aquaculture improvement and fisheries recruitment.

FAO, 2009. The State of World Fisheries and Aquaculture. FAO (Food and Agriculture Organization of the United Nations), Rome, pp.

O'Rorke, R., Lavery, S., Chow, S., Takeyama, H., Tsai, P., Beckley, L. E., Thompson, P. A., Waite, A. M., Jeffs, A. G. (2012). Determining the Diet of Larvae of Western Rock Lobster (Panulirus cygnus) Using High-Throughput DNA Sequencing Techniques. PloS one, 7: e42757.

Phillips, B. F., Melville-Smith, R., 2006. Panulirus Species. In: Secondary Phillips, B. F., Melville-Smith, R. (Eds.), Lobsters: Biology, Management, Aquaculture and Fisheries. Blackwell Publishing Ltd, Place Published, pp. 30.

Phillips, B. F., Booth, J. D., Cobb, J. S., Jeffs, A. G., McWilliam, P. (2007). Larval and

postlarval ecology. Lobsters: biology, management, aquaculture and fisheries:

231-262.

Effect of Temperature and tank size on hatching rate and survival of eggs and larvae of Orange-spotted grouper (Epinephelus coioides)

Hojatollah Fouroofghifard , Kayomars Rohani Ghadikolaee Eesa Abdolalian, Maryam Moezi, Essa Kamali, Masoud Gharibnia

Abstract

Groupers are one of the most important species for the quality of their flesh, and high market prices. Eggs of Orange-spotted grouper (Epinephelus coioides) were obtained of reared brood stocks during February till mach 2012. In order to determine the best water temperature, for incubation of eggs , four treatment of various ranges of temperature included 23-24 , 26-27 and 28-29 °C 31-32 °C were arranged. Experiments were conducted in 300 liter polyethylene tanks which contained , 200 liter water. Eggs were stocked as a density of 25 eggs per liter. In order to obtain the best tank size, 40 liter aquarium , 300 liter polyethylene tanks and also 2400 liter fiber glass tanks were compared. Hatching rate were obtained by counting the larvae after 1 DAH. Survival rates were obtained by counting the number of survival larvae per liter , on days : 1 ,5 10,20 and 30 DAH per liter . Results of comparison between various levels of water temperature on hatching rate of Epinephelus coioides , indicated significant differences between them . The best range of temperature for hatching was 28-29 C . Survival rates of larvae until 30 Days After Hatching (DAH) was better in bigger tanks than the others .

Marine Species aquaculture such as shrimps and marine fishes has been regarded as an important contributor to the economies of southern provinces of Iran, Technique of Artificial Reproduction and seed production of some species of marine fish such as , yellow fin sea bream (Acanthopagrus latus ) and Sobaity sea bream ( sparidentex hasta ) has been almost expanded and some species such as Rabbit fish ( siganus sutor ) and grouper ( Epinephelus coioides ) are still at the embryo stage . (, Bahmani etal. 2009 ,Fourooghifard et al. 2009 , Abbassi et al. 2008 , Fourooghifard & Daghooghi , 2006 ).

Groupers are classified in 14 genera of the subfamily Epinephelinae, which comprises at least half the approximately 449 species in the family Serranidae. They are found Throughout most warm and temperate marine regions. serranids are highly valued for food, and both small and large species are kept in aquariums (Tucker 1999 )

Groupers are highly valued for the quality of their flesh, and high market prices. Groupers are the most intensively exploited group in the fish trade, and the high prices paid by exporters to local fishermen mean that target species may be heavily over-fished (Morris et al. 2000).

Epinephelus coioides occurs in the western Indian Ocean from the southern Red Sea to Natal and east to the western Pacific where it is distributed from Ryukyu Islands to New South Wales. It ranges east into Oceania only to Palau in the Northern Hemisphere and Fiji in the Southern. Orange-spotted groupers inhabit turbid coastal reefs and are often found in brackish water over mud and rubble. Juveniles are common in the shallow waters of estuaries over sand, mud and gravel and among mangroves, feeding on small fish, shrimp, and crabs. E. coioides are Epinephelus coioides like other Serranids species are protogynous hermaphrodites. They first

mature as females at around 3-4 kg body weight. Some of the fastest growing females transform into males when they reach more than 6 kg body weight. Because of the difficulty in obtaining mature males, studies to develop methods to induce sex-inversion in juveniles and adults were

undertaken (Tan-Fermin, 1992; Tan-Fermin et al., 1994)

Eurythermal and Euryhaline . The major spawning period is March to June. Females mature at 250-300 mm TL at an age of 2-3 years; sexual transition occurs at a total length of 550-750 mm. Fecundity estimates varied from 850 186 ova in a 350 mm TL fish to 2 904 912 ova for one of 620 mm TL. Eggs are pelagic; best survival of larvae is attained at 30 °C and 30 %%. Successful artificial propagation of e. coioides has been reported in Malaysia. They probably spawn during restricted periods and form aggregations when doing so and the eggs and early larvae are probably pelagic. ( FAO, 2012)

Grouper larvae are stocked at relatively high density: 20-30 per litre (Ruangpanit, 1993; Duray et al., 1996). In general, the main factors that determine larvae mortality are biotic factors (for example food, disease, parasitism and predation) and abiotic factors (for example oxygen, pH, salinity, toxic substances and temperature) (Kamler 1992).

Material and Methods

Eggs of Orange-spotted grouper (Epinephelus coioides) were obtained of reared brood stocks during February till mach 2012. A running water and aeration system were designed to get eggs moved forward an eggs collector (figures 1).

In order to determine the best water temperature, for incubation of eggs , four treatment of various ranges of temperature were arranged . they included 23-24 (natural temperature of water without using any heaters) , 26-27 and 28-29 °C 31-32 °C ( by using of adjustable Aquarium heaters) with 3 replications . Experiments were conducted in 300 liter polyethylene tanks which contained , 200 liter water. Eggs were stocked as a density of 25 eggs per liter (fig 2)

Size of rearing tanks were also examined to obtain the best tank size and defining the problems efficiency of each tank , we set 3 treatments .by 3 replication . we used 40 liter aquarium ( 50*30*30 ) (filled with 30 liter water) , 300 liter polyethylene tanks (filled with 200 liter water) and also 2400 liter fiber glass tanks (height ; 130 cm , diameter : 150 cm)

 (filled with 2000 liter water), larvae were fed by Nannochloropsis and baby of rotifer Brachionus plicatilis at a density in sequence ,500000 cell/ml and 15-20 ind/ml Hatching rate were obtained by counting the larvae after 1 DAH. Survival rates were obtained by counting the number of survival larvae per liter , on days : 1 ,5 10,20 and 30 DAH per liter . Overall Results revealed that The survival of grouper larvae can be improved by the use of large tanks and controlling of temperature water.

Temperature (°C)

Fig 1 ) Hatching Rates of Epinephelus coioides in various Range of Temperature

40 L Aquarium        300 L Poly ethylen       2400L Fiber glass tanks tanks

Kind of Tanks

Fig 2 ) Hatching Rates of Epinephelus coioides in various kind of tanks

I 80 = 70

9

S so

£ 40

H JO

S 20

| 10

3 o

' 1 S 10 20 30

Days After Hacliiug

40LAquari»m       300 L Poly ethylen     > 2400 L Fiberglass

Fig 3) survival Rates of Epmephehts coioides in various size of tanks

Results

Results of comparison between various levels of water temperature on hatching rate of Epinephelus coioides, indicated significant differences between them. ( P< 0.05) . at the range 23-24 the hatching rate was 0 . The best range of temperature for hatching was 28-29 C. (Fig 1)

Results also indicated that there weren't any differences between the hatching rates of eggs in various size of tanks ( p > 0.05 ) .(fig 2 )

Survival rates of larvae until 30 Days After Hatching (DAH) was better in bigger tanks than the others . there was a significant difference between Survival rates of larvae in Aquarium and 300 liter poly ethylene tanks and 2000 liter fiber glass tanks ( P< 0.05) . (fig3 )

According to the observations and Data obtained of larvae counting, there were a huge decrease of larvae density on days 5 and 20 .( fig 3 )

after 30days of rearing period the best survival rate was obtained in 2400 L fiberglass tanks with a rate of 16 ± 9.94 % .

Discussion

Results of comparison between various levels of water temperature on hatching rate of Epinephelus coioides , indicated that the best range of temperature for hatching was 28-29 C . ( fig1 )

Sugama in 2004 reported that growth of humpback grouper larvae

Cromileptes altivelis ,increased with increasing of water temperature. According to this report The highest survival (48.11%) was found for the larvae reared at 28°C that was much higher , compared with the survival of larvae reared at 31°C, which was only 4.77%.

Akatsu et al. (1983) reported that for brown spotted groupe Epinephelus tauvina , reared for 12 days at different water temperatures. Total length of larvae reared at high temperature (32°C) was the highest (6.5 mm) compared with larvae reared at 23°C (4.1 mm).

According the observations and data obtained of larvae counting, there were a huge decrease of larvae density on days 5 and 20 .( fig 3 )

High mortality associated with the commencement of exogenous feeding. This mortality may be associated with the provision of live prey organisms of unsuitable size and nutritional composition, but even when 'suitable' prey types are used, there is generally high mortality at this stage (Ordonio-Aguilar et al., 1995; Duray et al., 1997). Several mortality syndromes have been described for grouper larvae. A commonly reported mortality syndrome is the 'shock syndrome' that occurs in late stage larvae from about D25 (Lim, 1993; Duray et al., 1997). This problem may be related to nutritional deficiencies in the live prey organisms used to feed the larvae, since shock syndrome is symptomatic of low levels of HUFAs in the diet (Cowey & Sargent,

1972).

Survival rates of larvae until 30 Days After Hatching (DAH) was better in bigger tanks than the others. Results revealed that by increasing of tanks size the survival rate of larvae increase. After 30days of rearing period the best survival rate was obtained in 2400 L fiberglass tanks with a rate of 16 ± 9.94 %.

Tank size, shape and color can affect the survival of grouper larvae cultured. . E. coioides larvae cultured in 3 m3 tanks demonstrated a better survival rate (19.8%) at Day (D) 24 compared with only 7.4% for those in 0.5 m3 tanks at D21 (Duray et al., 1997)

Overall results revealed that The survival of grouper larvae can be improved by the use of large tanks and controlling of temperature water.

Akatsu, S., Al-Abdul-Elah, K.M. and Teng, S.K. 1983. Effects of salinity and water temperature on the survival and growth of Brown Spotted grouper larvae ( , SERANIDAE). J. World Maricult. Soc. 14: 624-635.

Duray , M.M. ; C.B. E studillo and L.G. Alpasan . (1996). The effect of background colour and rotifer density on rotifer intake, growth and survival of the grouper (Epinephelus suillus) larvae. Aquaculture 146, 217-225.

Duray , M.M. ; C.B. E studillo and L.G. Alpasan.(1997). Larval rearing of the grouper Epinephelus suillus under laboratory conditions. Aquaculture 150, 63-76.

FAO. © 2010-2012. Cultured Aquatic Species Information Programme. Epinephelus coioides. Cultured Aquatic Species Information Programme. Text by Shams, A.J. In: FAO Fisheries and Aquaculture Department [online]. Rome. Updated 2010. [Cited 5 August 2012].

Morris, A. V.; Roberts, C. M.; Hawkins, J. P., 2000: The threatened status of groupers (Epinephelidae). Biodivers. Conserv. 9, 919- 942.

Tan-Fermin, J.D. 1992. Withdrawal of 17 alpha-methyltestosterone causes reversal of sexinversed male grouper Epinephelus suillus (Valenciennes). Philipp. Scient.

29:33-39.

Tan-Fermin, J.D., Garcia, L.M.B. and Castillo, A.R. 1994. Induction of sex inversion in juvenile grouper Epinephelus suillus (Valenciennes) by injections of 17 alphamethyl testosterone. Jpn. J. Ichthyol. 40:413-420.

Tucker , J. , W., Jr. , 1999 . Grouper Aquaculture SRAC Publication No. 721

Abbassi F , Oryan S , Matinfar A.2008. Iinteraction of Ovarian Development and Gonadal Hormones In Epinephelus Coioides of Pesian Gulf . Pajouhesh -va-Sazandegi ; 21(2 (79 In Animal And Fisheries Sciences )):72-80

Bahmani, M ; A. Sarvi Gheeyasabadi ; R. Kazemi, and F. Sarvi Gheeyasabadi, (2009). A study on embryonic development of Yellow Fin Seabream (Acanthopagrus latus). Iranian Science Fisheries Journal 18 (1), 33-42.

Fourooghi-e-fard H. and B. Daghooghi B. , 2006 . Comparison of growth and Maturation of rabbitfishes (Siganus javus, S. sutor) in the concrete tanks in Hormozgan province Pajouhesh & Sazandegi No:68 pp: 77-84( in Persian , English abstract)

Fourooghi Fard, H.; B. Daghooghi, ; Y. Aftabsavar, 2009 . Reproductive biology of the white spotted rabbit fish, Siganus sutor, in culture conditions. Iranian

Scientific Fisheries Journal 2009 Vol. 18 No. 3 pp. 119-128 ( in Persian ,

English abstract)

Lim, K.J. ; C.L. Yen ; T.S. Huang ; C.Y. Lim and C.L. Chen. (1986). Experiment of fry nursing of E. salmonoides and its morphological study. Bulletin of the Taiwan Fisheries Research Institute 40, 219-240. In: Rimmer M. , 2000 . Review of grouper hatchery technologySPC Live Reef Fish Information Bulletin number 7 pp. 14- 19

Ordonho-Aguilar, R.; H. , Kohno ; A., Ohno ; M. Moteki & Y. Taki. (1995).

Development of grouper, Epinephelus coioides, larvae during changeover of energy sources. Journal of Tokyo University of Fisheries 82, 103-108.

Sugama K.; Trijoko ;S. Ismi and K. Maha Setiawati 2004 Effect of Water Temperature on Growth, Survival and Feeding Rate of Humpback Grouper ( Cromileptes altivelis ) Larvae in : Advances in Grouper Acquaculture Edited by M.A. Rimmer, S. McBride and K.C. Williams ACIAR Monograph 110 (printed version published in 2004)

Tan-Fermin, J.D. 1992. Withdrawal of 17 alpha-methyltestosterone causes reversal of sexinversed male grouper Epinephelus suillus (Valenciennes). Philipp. Scient.

29:33-39.

Tan-Fermin, J.D., Garcia, L.M.B. and Castillo, A.R. 1994. Induction of sex inversion in juvenile grouper Epinephelus suillus (Valenciennes) by injections of 17 alphamethyltestosterone. Jpn. J. Ichthyol. 40:413-420.

Ruangpanit , N. (1993). Technical manual for seed production of grouper (Epinephelus malabaricus).National Institute of Coastal Aquaculture, Department of Fisheries, Ministry of Agriculture and Cooperative, and The Japan International Cooperation Agency. 46 p. in : Rimmer M. , 2000 . Review of grouper hatchery technologySPC Live Reef Fish Information Bulletin number 7 pp. 14- 19

Effects of dietary ascorbic acid and density interaction on Sexual hormones in rainbow trout

(Oncorhynchus mykiss)

Ghaderi Z1* ., Falahatkar B1., Noveirian H1., Shafaeipoor A2

1 Fisheries Department, Faculty, of Natural Resources, University of Guilan, Sowmeh Sara, Guilan, Iran.

2 Biology Department, Faculty of Science, Yasuj University, Yasouj, Iran * Email: ghaderifz @ yahoo. com

Abstract

This study was conducted investigate the interaction effects between ascorbic acid and density on Sexual hormones in rainbow trout (Oncorhynchus mykiss).Six treatments supplemented three diets with 0, 100 and 1000 mg/kg L-Ascorbyl-2- Polyphosphate (APP) as vitamin C, in interaction with two densities, supplemented high density (4.33 kg/m3) and low density (2.16 kg/m3) were fed to rainbow trout brood stock in three replicates for 16 weeks. Eighty one fish with an average weight 812+1.5 g were distributed to each tank with dimensions of 1x1.5x0.75m and to fill a tank with water volume 910L. After two weeks adaptation to the experimental diet. In spawning time with each replicate for treatments with high density from 3 fish and for treatments with low density from two fish to be done blooding, then samples of blood for study of sexual hormones (progesterone, testosterone and estradiol) performed. Results indicated don't exist significant interaction effect and don't significant difference progesterone (P>0.05) and exist significant difference in estradiol and testosterone. Results suggest that use of ascorbic acid for reproduction, required value of growth. And confirm the positive function of ascorbic acid also don't confirm function of density in this study.

Keywords: Oncorhynchus mykiss, Reproductive, Density, Vitamin C, Sexual Hormone

Brood stock nutrition is without doubt one of the most understood and researched areas of fin fish nutrition (Izquierdo et al., 2001). Food restriction itself can seriously affect spawning success (Izquierdo et al., 2001). In female brood stock, the fast growth of oocytes embryonic development and early performance of fry are critically affected by the supply of nutrients during vitellogenesis (Blom & Dabrowski, 1995). Vitamin C (ascorbic acid) is a strong antioxidant (Lee & Dabrowski, 2004). Ascorbic acid is an essential micro nutrient in the diet of teleost fish (Dabrowski & Ciereszko, 2001). Recent study showed decreased levels of estradiol-17p and vitellogenin during fast ovary growth in rainbow trout fed a diet devoid of ascorbic acid (Waagbo et al., 1989). Beneficial effects of ascorbic acid supplementation in brood stock diets on fish fertility have been shown in rainbow trout, Oncorhynchus mykiss (Falahatkar et al., 2006). Stocking density is a major factor affecting fish growth under farmed conditions (Jobling, 1985).

Materials and methods

The research was carried out at the private nursery ponds of Fish Seed Farm, Fars Ghezel kaman, Shiraz Iran. The experiment was conducted for a period of 16 weeks from August to, February 2010 in Six treatments including three diets with 0, 100, 1000 mgkg-1 L-Ascorbyl-2-polyphosphate as source of vitamin C and two densities with six fish for high and three fish for low density. Fish were hold to each tank with 1x1.5x0.75 m dimensions and were fed in three replicates for 16 weeks. Fish (average weight 812 + 1.5 g) were acclimated to experimental diet for 14 days. Fish were weighed and measured total length each 4-week interval. In spawning time with each replicate for treatments with high density from 3 fish and for treatments with low density from two fish to be done blooding, then samples of blood for study of sexual hormones (progesterone, testosterone and estradiol) performed. For this about used of Babilon kit/USA with ELISA method.

Composition of the basal diet is shown in Table 1. Three diets were formulated to contain 0, 100 and 1000 mg L-Ascorbyl-2-polyphosphate as source of vitamin C per kg diet.

Table 1. Composition of the experimental basal diet

Ingredients %

Fish meal 60

Wheat Gluten 5

Wheat meal 18

Soya meal 10

Vitamin & Mineral premix1 5

Fish oil 2

AA2 0

Total 100

Requesting vitamin & mineral for rainbow trout of VDS Company of Belgium 2 L-ascorbyl - 2 polyphosphate (EASF- Belgium)

All ingredients were mixed and pelleted by a labratoary pellet machine without heating using a 5mm diameter module. After production, diet analyzed and percentage of Prorein, moisture, Lipid, Fibr and Ash determined (Table2).

Density: in this study two densities are used, as treatments with interaction to diets. These are high density (4.33 kg/m3) and low density (2.16 kg/m3).

Table 2. Analyzed dietary

Ingredients

%

Protein1

46.2+0.9

Moisture

9+0.2

Lilpid2

12.1+0.2

Fibr3

3+0.1

Ash

8.5+0.1

1Analyze method: kjeldahl, 2 Soxhlet, 3Hydrolize, (Association of Official Analytical Chemists (AOAC), 2002)

Statistical analysis

All data were analyzed by Two-way ANOVA (spss, Chicago, 1L) with interaction to test for the effects of the dietary treatments. When a significant treatment effect was obsverd, a tuky test was used to compare means. Treatment effects were considered with the significant level at P<0.05.

Results indicated dont exist significant interaction effect and dont significant difference progesterone (P>0.05) and exist significant difference in estradiol and testosterone (Table 3) & (Table 4). Results suggest that use of ascorbic acid for reproduction, required value of growth. And confirm the positive function of ascorbic acid also don't confirm function of density in this study.

Table 3: Two-way ANOVA results of dietary vitamin C levels or Stocking densities, and their interaction on, sexual hormones in rainbow trout for 16 weeks

Parameter

Diet

Stocking densities

Diet x Stocking densities

Progesterone (ug/dl)

0.000*

0.000*

0.186 ns

Testosterone (ug/dl)

0.000*

0.027*

0.047*

Estradiol (ug/dl)

0.000*

0.000*

0..000*

*Significant

nsnot significant

 

 

Table 4: Effect of stocking density and diet composition on sexual hormones in rainbow trout

Diet

 

Stocking

Progesterone

Testosterone

Estradiol

 

 

density

(Ug/dl)

(Ug/dl)

(Ug/dl)

-C

6

 

1.43±0.18b

0.93±0.23b

2.08±0..06c

-C

3

 

0.60±0.11c

1.42±0.32a

1.09±0.15de

C100

6

 

1.67±0.40b

0.94±0.06b

3.61±0.40b

C100

3

 

0.61±0.04c

0.90±0..05b

0.78±0.12e

C1000

6

 

2.21±0.35a

1.92±0.13 a

4.34±0.45a

C1000

3

 

1.6±0.49b

2.08±0.55a

1.24±0.06d

Data in the table were mean and standard deviation (mean±S.D.). The different superscripts in the same row show significant difference (P<0.05).

Discussion

It is well estabilished that the phosphate derivatives of AA equimolar basis in channel catfish (El Naggar and Lovell, 1991); tilapia (Soliman et al., 1986; Shiau and Hsu, 1995); rainbow trout (Matusiewicz et al., 1995).

Matusiewicz and Dabrowski(1995) shown that phosphate derivatives of AA could be hydrolyzed by the action of rainbow trout intestinal alkaline phosphatase. Results of dietary vitamin C levels or Stocking densities, and their interaction on sexual hormones in rainbow trout for 16 weeks indicated don t exist significant interaction effect and don t significant difference progesterone and exist significant difference in estradiol and testosterone. When fish were fed the diets supplemented with L-ascorbyl - 2 polyphosphate sexual hormones increased. Recent study showed decreased levels of estradiol-17P and vitellogenin during fast ovary growth in rainbow trout fed a diet devoid of ascorbic acid (Waagbo et al., 1989).

References

Blom, J. H. and Dabrowski, K. 1995, Reproductive success of female rainbow trout (Oncorhynchus mykiss) in response to graded dietary ascorbyl monophosphate levels. Biology. Reprod, 52: 1073-1080.

Dabrowski, K., Ciereszko, A., 2001.Ascorbic acid and reproduction in fish: endocrine regulation and gamete quality. Aquaculture Research 32, 623-638

El Naggar, G.O., Lovell,R.T., 1991. L-Ascorbyl-2monophosphate has equal antiscorbuttic activity as L-Ascorbic acid but L-Ascorbyl-2sulfate is inferior to L-Ascorbic acid for channel catfish. J.Nutr. 121, 1622-1626.

Falahatkar, B., Dobrowski, K., Arslan, M., Rinchard, J., 2006. Effect of ascorbic acid enrichment by immersion of rainbow trout (Oncorhynchus mykiss, Walbaum 1792) eggs and embryos. Aquaculture Research 37: 834-841.

Jobling, M. 1985. Physiological and social constraints on growth of fish with special reference to arctic charr Salvelinus alpines L. Aquacult, 44: 83- 90.

Matusiewicz, M., Dabrowski, K., Ludwig, V., Matusiewicz, K., 1994. Regulation of saturation and depletion of ascorbic acid in rainbow trout. Journal of Nutritional Biochemistry 5: 204-211.

Shiau, S.Y. and Hsu, 1995 T.S. Vitamin C requirements of grass shrimp Penaa odon, as determined with L-ascorbyl-2-monophosphate, Aquacult, 122,345.

Soliman, A.K., Jauncey, K. and Roberts, R.J.1986, The effect of dietary ascorbic acid supplementation on hatchability, survival rate and fry performance in Oreochromis mossambicus (Peters). Aquacult, 59:197-208.

Waagb0, R., Thorsen, T. and Sandnes, K. 1989, Role of dietary ascorbic acid in vitellogenesis in rainbow trout (Salmo gairdneri). Aquacult, 80: 301-314

Introducing standard protocol for Enrichment of Artemia urmiana nauplii with Canola Oil

Sirwe Ghaderpour1, Naser Agh2*, Farzaneh Noori2 and Eslam Ahmadian1

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