Автор неизвестен - Krmulture in iran - страница 3

Страницы:
1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53 

Saeed Ziaei-Nejad, Gholamraza Rafiee, Alireza Mirvaghefi, Hamid Farahmand

A survey of blood parameters in ship (Acipenser 832 nudiventris) broodstocks under rearing condition

Zohrabi, M.; Nasri Tajan, M.; Kazemi, R.; Bagherzadeh Lakani, F, Pourdehghani. M.

A survey of blood parameters in Acipenser stellatus 833 broodstocks under rearing condition

Zohrabi, M. ; Nasri Tajan, M. ; Kazemi, R. ; Bagherzadeh Lakani, F and Pourdehghani.M

FuttPapers

Fecundity and egg diameter variation in Saurida tumbil, in the Persian Gulf

Akbar Abaszadeh1*, Yazdan Keivany2, Nasrollah M. Soofiani2 and Ali Falahati1

department of Fisheries, Faculty of Natural Resources, Persian Gulf University,

Bushehr, 75169-13798, Iran 2Department of Natural Resources  (Fisheries Division), Isfahan University of

Technology, Isfahan, 84156-83111, Iran.

Abstract

A total of 538 female specimens of the greater lizardfish, Saurida tumbil, were collected from the Persian Gulf, Bushehr Province, from Feb 2007 to Feb 2008. Mean absolute and relative fecundity was calculated as 263162+31046 and 273+27, respectively. The minimum and maximum ova diameter was 6|i (stage 1) and 875^ (stage 5) with a mean+SD of 318+62 ^. The curvilinear relationship between the fecundity and total weight of the fish was F=2657.8 W a6617.

Introduction

The greater lizardfish, Saurida tumbil, is a member of the family Synodonthidae and are common and widely distributed through Indian and Pacific waters, the Oman and Arabian seas and the Persian Gulf and it is commercially important for the local fishery.

The greater lizardfish inhabits sandy, muddy or coral reefs from the coastal line to depth of 100m. Greater lizardfish is most abundant species in both number and weight found in demersal fish assemblages in the Persian Gulf. In Bushehr Province, it is taken by many fishing methods, including bottom trawl and gill nets, however, its abundance has decreased steadily in the recent years in the world (Froese and Pauly, 2012). Ecological factors affect the biological and reproductive characteristics of fish population, and so these kinds of investigations

should be carried out periodically and determining the reproductive biology of a species within its native range is necessary for management purposes. The main purpose of the present investigation was to study reproduction biology of S. tumbil, including fecundity and egg diameter variations in Bushehr Province, in south of Iran.

Materials and methods

The study was carried out on a S. tumbil population in the Persian Gulf. Monthly collections were made from February 2007 to February 2008, where a total of 538 female S. tumbil specimens were collected from commercial fishing boats in Bushehr Province, Iran. These specimens were caught by gillnet and trawls during the early morning hours and brought to the laboratory fresh on ice. Total length (TL) and body weight (BW) were recorded from the specimens to the nearest 1 mm and to the nearest 1 g, respectively. The gonads were dissected from the fish and weighted to the nearest 0.01 g (GW) while the sex was determined by visual inspection. Fecundity was estimated by using wet weight technique. After weighing the ovaries, 3-5 subsamples of known weight were extracted from different parts of the ovary lobe and each subsample weighed to the nearest 0.001 g and then counted.

Results

The length frequency of S. tumbil specimens collected in this study is shown in Fig.1. The most abundant group of females belonged to the 43.1­48 cm. Mean absolute and relative fecundity was 263162 + 31046 and 273 + 27, respectively. The minimum and maximum ova diameter was 6| (stage 1) and 875^ (stage 5) with a mean of 318+62 ^. The curvilinear relationship between the fecundity and total weight of the fish was

F=2657.8 W 0.6617 (Fig. 2). The first year maturity size (TL) for females

was 27 cm. Ovaries contained oocytes at various stages of development. Oocyte development of greater lizardfish collected along the northern coast of the Persian Gulf was consistent with batch spawning that exhibit synchronous development. Females at maturity stages III -V were mature.

Information regarding the reproductive biology of the S. tumbil species in Persian Gulf is quite limited and the sample size of previous studies were inadequate. In the present study, we elucidated the fecundity and egg diameter variation of greater lizardfish in this area. Fecundity varied from a mean of 140742 + 8541 eggs per female at weight 399 g to a mean of 456985 + 24218 eggs per female at weight 1470 g. This was correlated significantly with fish weight, body length, age and gonad weight, and it is increased as gonad weight and fish length increased. Soofiani et al. (2006) showed that the number of eggs in this fish ranged between 74444 and 250452 in a nearby population.

One of the most important parameters used to define reproductive potential is the variation of egg diameter in the ovaries. The minimum and maximum ova diameter was correlated with fish weight, length and gonad weight. Egg diameter may be related to the amount of food that females can metabolize (Nikolsky, 1963). During the year, different combinations of oocyte types were seen within the ovary. Fully grown and mature oocytes were detected in May and October. These results are in line with other studies (Budnichenko & Nor, 1978; Soofiani et al., 2006; Budnichenko, 1974).

Morphologically, the attack of follicular atresia is revealed by hypertrophy of the granulose layer, followed by digestion of the vitelline envelope, split of the cytoplasmic cortex, and nuclear membrane decomposition (early atresia). Then it is followed by rapid phagocytosis of the oocyte yolk (inter -mediate atresia) and formation of the atretic body attacked by the transformed follicular and blood-borne cells with a capillary infiltration (late atresia). During the spawning season postovulatory follicles were observed together with oocytes at yolk stage in ovaries of greater lizardfish as well as another close lizardfish species (Budnichenkoo and Dimitrova, 1979). We believe that our study provides some important information on the reproductive biology of S. tumbil that will be helpful in similar studies.

Fig. 2. Relationship between the fecundity and total weight in S. tumbil

Budnichenko, V.A. 1974. The feeding of Saurida undosquamis and Saurida tumbil (Synodontidae) along the Oman Coast. Journal of Ichtyology. 14: 297-272.

Budnichenko, V.A. and L.A. Nor. 1978. Some features of the growth of Saurida undosquamis and Saurida tumbil (Pisces Synodontidae) in the Arabian Sea. Journal of Ichthyology. 18: 750-755.

Budnichenko, V.A. and O.S. Dimitrova. 1979. The reproductive biology of Saurida undosquamis and Saurida tumbil (Family: Synodontidae) in the Arabian Sea. Journal of Ichthyology. 19: 80-86.

Froese, R. and D. Pauly. 2012 (Eds). Fishbase worldwide web electronic publication.

WWW. Fishbase. Org.

Nikolsky, G.v., 1963. The Ecology of Fishes (Translated by L. Birkett), Academic press, London, 352 p.

Soofiani, N.M., Y. Keivany and A.M. Shooshtari. 2006. Contribution to the biology of the Lizardfish, Saurida tumbil (Teleostei: Aulopiformes), from the Persian Gulf. Zoology in the Middle East. 38: 49-56.

Fecundity and egg diameter variations in Saurida tumbil from Bushehr coastal waters

Akbar Abaszadeh1*, Yazdan Keivany2, Nasrollah M. Soofiani2 and Ali Falahati1

1 Department of Fisheries, Faculty of Natural Resources, Persian Gulf University, Bushehr, 75169-13798, Iran.

2 Department of Natural Resources (Fisheries Division), Isfahan University of Technology, Isfahan, 84156-83111, Iran. E-mail: keivany @ cc.iut.ac.ir

Abstract

A total of 538 female specimens of the greater lizardfish, Saurida tumbil, were collected from the Persian Gulf, Bushehr Province, from February 2007 to February 2008. Mean absolute and relative fecundity was calculated as 263162+31046 and 273+27, respectively. The minimum and maximum ova diameter was 6|i (stage 1) and 875|i (stage 5) with a mean+SD of 318+62 |i. The curvilinear relationship between the fecundity and total weight of the fish was F=2657.8 W °'6617.

Keywords: Biology, Lizardfish, Persian Gulf, reproduction, Synodontidae

Introduction

The greater lizardfish, Saurida tumbil, is a member of the family Synodonthidae and are common and widely distributed through Indian and Pacific waters, the Oman and Arabian seas and the Persian Gulf and it is commercially important for the local fishery. The greater lizardfish inhabits sandy, muddy or coral reefs from the coastal line to depth of 100m. Greater lizardfish is most abundant species in both number and weight found in demersal fish assemblages in the Persian Gulf. In Bushehr Province, it is taken by many fishing methods, including bottom trawl and gill nets, however, its abundance has decreased steadily in the recent years in the world (Froese and Pauly, 2012). Ecological factors

affect the biological and reproductive characteristics of fish population, and so these kinds of investigations should be carried out periodically and determining the reproductive biology of a species within its native range is necessary for management purposes. The main purpose of the present investigation was to study reproduction biology of S. tumbil, including fecundity and egg diameter variations in Bushehr Province, in south of Iran.

Materials and methods

The study was carried out on a S. tumbil population in the Persian Gulf. Monthly collections were made from February 2007 to February 2008, where a total of 538 female S. tumbil specimens were collected from commercial fishing boats in Bushehr Province, Iran. These specimens were caught by gillnet and trawls during the early morning hours and brought to the laboratory fresh on ice. Total length (TL) and body weight (BW) were recorded from the specimens to the nearest 1 mm and to the nearest 1 g, respectively. The gonads were dissected from the fish and weighted to the nearest 0.01 g (GW) while the sex was determined by visual inspection. Fecundity was estimated by using wet weight technique. After weighing the ovaries, 3-5 subsamples of known weight were extracted from different parts of the ovary lobe and each subsample weighed to the nearest 0.001 g and then counted.

Results

The length frequency of S. tumbil female specimens collected in this study is shown in Fig.1. The most abundant group of females belonged to the 33.1-38 cm. Mean absolute and relative fecundity was 263162+31046 and 273+27, respectively. The minimum and maximum ova diameter was 6|i (stage 1) and 875|i (stage 5) with a mean of 318+62^. The curvilinear relationship between the fecundity and total weight of the fish was

F=2657.8 W 0.6617 (Fig. 2). The first year maturity size (TL) for females

was 27 cm. Ovaries contained oocytes at various stages of development. Oocyte development of greater lizardfish collected along the northern

coast of the Persian Gulf was consistent with batch spawning that exhibit synchronous development.

Fig. 1. Length frequency of S. tumbil females.

Fig. 2. Relationship between the fecundity and total weight in S. tumbil.

Discussions and Conclusions

Information regarding the reproductive biology of the S. tumbil species in Persian Gulf is quite limited and the sample size of previous studies were inadequate. In the present study, we elucidated the fecundity and egg diameter variation of greater lizardfish in this area. Fecundity varied from a mean of 140742 ± 8541 eggs per female at weight 399 g to a mean of 456985 ± 24218 eggs per female at weight 1470 g. This was correlated significantly with fish weight, body length, age and gonad weight, and it is increased as gonad weight and fish length increased. Soofiani et al. (2006) showed that the number of eggs in this fish ranged between 74444 and 250452 in a nearby population.

One of the most important parameters used to define reproductive potential is the variation of egg diameter in the ovaries. The minimum and maximum ova diameter was correlated with fish weight, length and gonad weight. Egg diameter may be related to the amount of food that females can metabolize (Nikolsky, 1963). During the year, different combinations of oocyte types were seen within the ovary. Fully grown and mature oocytes were detected in May and October. These results are in line with other studies (Budnichenko and Nor, 1978; Soofiani et al.,

2006).

Morphologically, the attack of follicular atresia is revealed by hypertrophy of the granulose layer, followed by digestion of the vitelline envelope, split of the cytoplasmic cortex, and nuclear membrane decomposition (early atresia). Then it is followed by rapid phagocytosis of the oocyte yolk (inter -mediate atresia) and formation of the atretic body attacked by the transformed follicular and blood-borne cells with a capillary infiltration (late atresia). During the spawning season postovulatory follicles were observed together with oocytes at yolk stage in ovaries of greater lizardfish as well as another close lizardfish species (Budnichenko and Dimitrova, 1979).

Acknowlegements

We would like to thank all the people helped us during the field work and fish sampling. This study was financially supported by Iran Fisheries Research Organization, Isfahan University of Technology and Persian Gulf University of Bushehr.

References

Budnichenko, V.A. 1974. The feeding of Saurida undosquamis and Saurida tumbil (Synodontidae) along the Oman Coast. Journal of Ichtyology, 14: 297-272.

Budnichenko, V.A. and Nor, L.A. 1978. Some features of the growth of Saurida undosquamis and Saurida tumbil (Pisces Synodontidae) in the Arabian Sea. Journal of Ichthyology, 18: 750-755.

Budnichenko, V.A. and Dimitrova, O.S. 1979. The reproductive biology of Saurida undosquamis and Saurida tumbil (Family: Synodontidae) in the Arabian Sea. Journal of Ichthyology, 19: 80-86.

Froese, R. and Pauly, D. 2012 (Eds). Fishbase. worldwide web electronic publication. WWW.Fishbase.Org.

Nikolsky, G.V. 1963. The Ecology of Fishes (Translated by L. Birkett). Academic Press, London, 352 p.

Soofiani, N.M., Keivany, Y. and Shooshtari, A.M. 2006. Contribution to the biology of the Lizardfish, Saurida tumbil (Teleostei: Aulopiformes), from the Persian Gulf. Zoology in the Middle East, 38: 49-56.

Biocontrol role of Pseudomonase aeroginosa (PTCC1430) in saprolegnia infection of Persian sturgeon (Acipenser persicus) eggs

Aghaei Moghaddam, A. A.1; Hajimoradloo, A.2; Ghiasi, M.3; Ghorbani, R. 4; Safari, R. 5;Haghparast, S.6.

1,2,4,6 Gorgan university of agriculture sciences and natural resources,Gorgan,Iran 3,5 Caspian Sea Eecology Research Institute,Sari,Mazandaran Province,Iran Corresponding author's E-mail: Aghaei fishery@yahoo.com

Introduction

Saprolegniasis is a serious mycotic winter freshwater fish disease, often affects wild and cultured fishes (Hussien et al, 2010) and is responsible for fungl infections and mortalities of fish and eggs. In hatcheries, infection usually begins in unfertilized eggs and spreads to live eggs which decrease the production (Noga, 2000). Sometimes, mortality rate by saprolegniasis in Acipenser persicus eggs during incubation has reached to 70 - 90% (Bauer et al, 2002). There are some chemical antifungal agents that are used to reduce saprolegniasis in hatcheries including formalin (Scherier, 1996), hydrogen proxide (Rach et al 2003), malachite green (Alderman, 1985) and etc. factors like health status of agents for human and environment, their ecological impacts, and long term effects to fish physiology, are very important points to choose them as antifungal agents. For example malachite green and formalin represented as low withdrawal affinity and high carcinogenic activity on human and fish (Osman et al, 2008). During the last decade, numerous aquatic bacteria have been found to be antagonistic to well-known aquatic bacteria pathogens (Lategan et al., 2004). Reports on the antifungal properties of bacteria have been centered mostly on the biocontrol of fungal Phytopathogens (Verschuere et al., 2000 and Gastwright et al., 1995). Antifungal activity against pathogenic Oomycetes has been tested in the genera Pseudomonas fluorescens (Bly, 1997 and Ahmadzadeh ,2006 ) Pseudomonas sp. (Adams, 2002), Aeromonas sp. (Hussein & Hataii, 2001;Osman et al., 2008 and Hussein

et al., 2011) Aeromonas media A199 (Lategan et al., 2003 and lategan et al., 2004) as a biocontrol agent for reduction of saprolegniasis.

The present study was designed to investigate potential biological agent for biocontrol of saprolegniasis in persian sturgeon eggs (Acipenser persicus) by Pseudomonase aeroginosa (PTCC1430) in sturgeon hatcheries.

Material and Methods

Preparation of P. aeroginosa PTCC1430

This strain was obtained originally from Persian Type Culture Collection, PTCC1430. Then it was grown in PDB (Potato Dextrose Broth) media. After centrifugation (1038 g) at 4 C for 10 min, bacteria sediment was separated from the media. Confidently, the sediment centrifuged three times. Afterwards, PBS (5 C) was added with the latest sediment and then shaked well with rotary shaker set. This liquid absorbance was read at 600 (nm) using a spectrophotometer (Gopalakannan and Arul, 2011).

The basic media was inoculated by bacterial concentration of 107 cfu. ml-1. The next treating concentrations (106,105cfu.ml-1) were prepared from this main bacterial solution.

Challenge design

Challenge design was carried out in Shahid Marjany Sturgeon Fish Center, Golestan province and preparation of P. aeroginosa was done in the Caspian Sea Eecology Research Institute, Mazandaran Province.

Green eggs from Persian Sturgeon (Acipenser persicus) were placed in Yushchenco Incubator trays. The thirty-hour eggs were confined within Nylonic cages (15x15x10 cm; 50 eggs per cage) (Abtahi et al 1994). During incubation and treating stages, water flow was about 2.5 l/min. Three cages were used as replicates for each treatment level and three cages used for control. Fish eggs were treated by three duration times (15, 30 and 45 min), three concentration levels of bacterial bath (105, 106 and 107 cfu. ml-1) and two times (once at first incubation day

and three times during the incubation period). Infected eggs were assessed, counted and picked up from cages daily.

Results and Discussion

As indicated in the table, there is only a significant effect of concentration (p< 0.01) while no significant effects of duration and times were found on egg fungal infection (p> 0.05). There is a significant interaction effect by times and bacterial concentration and also a significant interaction effect by all three studied factors (p< 0.05).

Regarding to the figure, there are significant differences between 13 treats and control (p<0.05). There were no significant differences between 4 treats of 107 cfu. ml-1concentration level and the control. The best effects were belonged to 105 x 30 min x1time and 105 x15min x3 times that reduce the fungal infections to 15% (as compared to the control with 44% egg fungal infection).

The ability of bacteria to inhibit saprolegnia infection might be implicated to its ability to liquefy gelatin of such fungi (Holt et al, 1993). Another candidate for the inhibitory activity for saprolegnia is cellulose (Hussein and Hatai, 2001). Bly (1996) reported that inhibition of saprolegnia by bacteria not related to the secretory substance but rather the result of competition (Bly et al, 1996) (Bly et al, 1997). In the present study, with increasing the concentration of bacteria, the effect of bacteria to control of fungal infections was reduced that could be related to extra cellular enzymes that might damage the egg membrane.

Acknowledgement

The authors are grateful of all colloquies of Shahid Marjani Sturgeon Fish Centre, The Caspian Ecology Research Centre and Golestan Fish Organization.

100

90 80 70 60 50

i 40 30 20

10 0

. 20

25.3

cd15;3cd 16

d    t d

rill

41.3

29.32433-32H8.627 6ab 32-729.3 2420.7bcdcd abcbcdbcdbcd T abc bcd

cd  cd    .    _    T    1    ,    .   H T

40.7 ab

45

1

1

I

25.3 cd

43.8 a

a

Treatment

Table: Analysis of variance of the effect of concentration, duration and times of bacterial treatments on fungal infections of Persian sturgeon eggs.

Sig.

F

Mean Square

df

Sum of Square

Source

0.00

**21.275

1444.222

2

2888.444

concentration

0.96

0.04

2.741

2

5.481

duration

0.718

0.131

8.914

1

8.914

times

0.67

0.592

40.185

4

160.741

Con. x dur.

0.015

*4.49

304.765

2

609.531

Con. x times

0.024

*3.944

267.728

2

535.457

Dur. x times

0.233

1.436

97.469

4

389.877

Con. x dur. x times

 

 

67.884

63

4276.667

Error

 

 

 

80

10263.802

Total

*. Shows significant difference at the level of 0.05 ** shows significant difference at the level of 0.01

Bauer, O, N. Pugachev and V.N. Voronin.2002. Study of parasites and diseases of sturgeon in Russia. A review .J. Appli. Ichthyol. 420-429

Hussien, A. M. Osman. Ahmad, I. E. Noor El Deen. Waled, S.E. Saman. 2010. A trial for I nduction of saprolegniasis in Mugil cephalus with special reference to biological control .Journal of American Science.6(6).203

Lategan M.J., F. R. Torpy and L. F. Gibson. 2004. Control of saprolegniosis in the eel Anguilla australis Richardson, by Aeromonas media strain A199.Aquaculture

204:19-27

Noga. E. J. 2000. Fish Diseases, Diagnosis and treatment. Inc. 367pp

Osman, H. M., W. E. Solman., A. E. Noor EL Deer and Laila A. Mohamed. 2008.,Induction of Saprolegniosis in Oreochromis niloticus with special reference to its Biological Control. Global veterinaria 2(1):32-37

Rach J. J., T. M. Schreier, Howe, G. E., and Redman,S.D.1997.Effect of species ,life stage, and water temperature on the toxicity of hydrogen peroxide to fish. Prog.

Fish. Cul.59:435-447

Schreier, T. M. Rach, J. J., and Howe,G.E.,1996.Efficacy of formalin ,Hydrogen Proxide and Sodium Chloride on fungal -infected rainbow -trout eggs.

Aquaculture. 140(4): 323-331

The effect of dietary blend vegetable oil on reproductive performance in rainbow trout (Oncorhynchus mykiss) broodstock

Naser Agh1, Ali Ehsani1, Reza Jalili2, Eslam Ahmadian2

1 Artemia and Aquatic Animals Research Institute, Urmia University, Urmia, Iran.

2 Department of Fisheries, Faculty of Natural Resources, Urmia University, Urmia, Iran.

Abstract

The present study was performed to examine the effect of replacing fish oil with blend vegetable oil on reproductive performance in rainbow trout. Rainbow trout broodstocks (4 years old) was fed 2 different experimental diets for 90 days. The control diet contained only fish oil and other remaining diet contained the canola:linseed:safflower oil blend (40:30:30, respectively) as the primary lipid source. Results showed fish oil replacement with vegetable oil hadn't significant effects on fish final weight, absolute fecundity, relative fecundity, eggs weight, eggs diameter, fertilization rate. But replacement of fish oil with vegetable oils resulted in significantly decreased total fecundity and hatching rate and increased larvae mortality and deformed larvae rate compared to control group (P < 0.05). However, no significant differences were detected in growth of fish fed fish oil and vegetable oil groups (P > 0.05).

Key words: Vegetable oil, Reproductive, Broodstock, Rainbow trout.

Introduction

Several factors affect egg and fry quality in fish species. These are either endogenous: genotype, age and size of broodstock, ovarian

characteristics, egg size and gamete age (Carillo et al. 2000) or exogenous: bacterial colonisation of egg surface, egg management, broodstock feeding (Bromage and Roberts 1995). In particular, reproductive performance is deeply affected by the nutritional status of fish, which is known to condition several reproductive traits, such as age at maturity, fecundity, egg size, chemical composition of eggs and also embryonic development (Carillo et al. 2000). In freshwater fish, embryonic development depends on the energetic reserves of the yolk sac. This is particularly true for Salmonids, as their embryonic structures are highly developed and their trophic function lasts for many days after hatching. Previous research demonstrated that changes in yolk composition, through diet and feeding levels, could also affect fry survival (Knox et al. 1988). Among dietary components a primary role is played by energy. In fact net energy requirements for maintenance are to be satisfied before growth and reproduction (Cho and Kaushik 1990). These authors, and others (Da Silva and Anderson 1995), pointed out that energy may be diverted from somatic growth when energy requirements for reproduction increase at the end of gonadal development. Maternal nutrition is the only source of fatty acids until the beginning of exogenous feeding. Watanabe et al. (1984) observed that lipid sources in broodstock diets affect egg quality, their hatching rate, also demonstrating that a dietary fatty acid deficiency could cause a decrease in gamete numbers and a high mortality of embryos. On the other hand, broodstock diets rich in polyunsaturated fatty acids (PUFA) increase the risks of eggs being exposed to peroxidation and tissue damage. As a consequence, PUFA level and the presence of antioxidant substances in the gamete are strictly related to egg quality (Pickova et al. 1999). The aim of this study was to evaluate the effects of two isolipidic and isoproteic diets, through the progressive replacement of fish oils (i.e., polyunsaturated fatty acids), with dietary blend vegetable oil (i.e., saturated fatty acids), on reproductive traits of rainbow trout.

Thirty six rainbow trout 4 year old broodstocks were stocked twelve (6 females/6 male) in 6 polyethylene tanks (1000 L) supplied with freshwater at a flow rate of 15 L min-1. Light/dark cycle was 8 L:16 D. Water quality parameters were monitored daily for each tank and pH, temperature and dissolved oxygen were maintained at 7.3-7.7, 14-15°C and 7.5-8.4 mg L-1, respectively. Two experimental diets with similar protein, lipid and energy content were formulated to contain blend vegetable oil sources to replace fish oil (Table 1). Kilka (Clupeonella sp.) meal and oil (Kilkapodre-sahar, Co, Iran) was the primary sources of fish meal and oil in the control and the experimental vegetable oil source was a mixture of canola: linseed: safflower oil (40:30:30, respectively). Table 2 shows the formulation and proximate composition of the experimental diets.

Three months after feeding (3 weeks before the full maturation of females), males and females were separated and each transferred to separate tanks. Fish were not fed after separate and checked for ripeness during the expected ovulation period weekly. To checking ovulation, fish were anaesthetized with 200 mg L-1 of clove solution before handling. Ovulated females, were separated and non-ovulated fish were returned to the tanks. Weight and total length of fish were measured. Gametes were collected and Pooled sperm were added. Then the gametes were gently mixed (2-3 min). Water was added to the gametes which were mixed, then rinsed ( 10-20 min ) and held for an additional 45 min for water-hardening . Eggs of each female were incubated in flow-through systems in incubation trays (with dimensions of 42.5 cm x 42.5 cm x 20 cm) randomly. Eggs of individual females were incubated and hatched separately. well water supplied at a flow rate of 9 L min-1 per 1kg of water-hardening eggs . All treatments were subjected to 2ppm formalin daily to prevent fungus infection.

Table 1. Reproductive performance of rainbow trout broodstock fed the experimental diets. (Mean ± std. n=6)

Dietary treatment 1

 

Fish oil (FO)

Vegetable oil (VO)

Fish early weight (g)

2661±233a

2816±366a

Fish final weight (g)

2790±240a

2945±305a

Total fecundity (g)

325±18a

288±22b

Absolute fecundity (N)

5586±850a

5155±1761a

Relative fecundity (N/kgbw)

1650±613a

2197±761a

Eggs weight (g)

0.069±0.012a

0.065±0.01a

Eggs diameter (ED)

4.87±0.07a

4.82±0.11a

Fertilization rate (FR)

99.33±0.28a

99±0.5a

Hatching rate (HR)

79±3.6a

52±6b

Larvae mortality (%)

11.6±1.5b

42.3±9.2a

Deformed larvae (%)

5.23±0.7b

33.65±7.7a

1 See Table 1 for diet abbreviations.

Table 2. Ingredient and proximate composition of experimental diets

Ingredients (g kg-1 diet)_FO_VO

Kilka fish meal

582.5

582.5

Kilka fish oil

128.9

-

vegetable oil

-

128.9

Blood meal

40

40

Wheat meal

145

145

Wheat starch

52.5

52.5

Zeolite

5

5

Vitamin premix

15

15

Mineral premix

10

10

Страницы:
1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53 


Похожие статьи

Автор неизвестен - 13 самых важных уроков библии

Автор неизвестен - Беседы на книгу бытие

Автор неизвестен - Беседы на шестоднев

Автор неизвестен - Богословие

Автор неизвестен - Божественность христа