Co-feeding of fish larvae with unrecorded nutrient and formulated diet has been at the focal point of fish dieticians since last decennary. In this survey we tried to polish the eating patterns of great hausen sturgeon ( Huso huso ) larvae utilizing different combinations of freshly hatched Artemia urmiana nauplii and trout starting motor diet. Three replicate groups ( 250 fish/replicate ) of first-feeding Huso huso larvae were fed on the footing of four chief feeding regimens: ( 1 ) live nutrient ( unrecorded nauplii of seawater runt Artemia urmiana ) ; ( 2 ) indirect passage ( 5 yearss live nutrient followed by gradual passage to formulated diet ) ; ( 3 ) direct passage ( utilizing different combinations of unrecorded and formulated diet from start feeding ) ; ( 4 ) formulated provender ( FD ) . It was found that uniting unrecorded nutrient and manufactured diets ( co-feeding ) from first eating phase ( direct passage ) significantly improves the weight addition in H. huso larvae followed by indirect passage, unrecorded nutrient and FD. But endurance was significantly higher in larvae Federal on pure unrecorded nutrient and direct passage regimens compared to indirect passage and FD. It was concluded that co-feeding of H. huso could be started instantly from beginning of exogenic eating.
Economically, sturgeons are really of import in Caspian Sea piscaries. Five different species of sturgeons, viz. Acipenser persicus, Acipenser stellatus, Acipenser nudiventris, Acipenser guldenstadti and Huso huso live in the Caspian Sea. Huso huso is the largest fish in the Caspian Sea bring forthing the most dearly-won roe. Therefore this fish has been the focal point of much attending in Iran since last decennary because it is peculiarly interesting species in footings of rise uping value. However, there is really small information on the eating forms of this fish. This is particularly true of the larval and juvenile phases, which are the most critical phases in the life-cycle of the fish.
At the oncoming of exogenic eating, different sturgeon species present an anatomically complete digestive piece of land with a pronounced specialisation of each of its different sections ( Buddington & A ; Christofferson, 1985 ; Gawlicka et al. , 1995 ; Gisbert et al. , 1998 ) . As a effect, unreal larval diets have been used for intensive commercial civilization of several acipenserid species from the oncoming of exogenic eating ( Charlon & A ; Bergot, 1991 ; Giovannini et al. , 1991 ; Hung, 1991 ; Gisbert & A ; Williot, 1997 ) . However, the terminal of the lecithotrophic phase and passage to exogenic eating still represents an of import beginning of larval mortality ( Buddington & A ; Christofferson, 1985 ; Giovannini et al. , 1991 ; Gisbert & A ; Williot, 1997 ; Bardi et al. , 1998 ) , proposing some nutritionary jobs associated with the digestion and assimilation of unreal diets, which are usually formulated for salmonids or marine fish species ( Hung, 1991 ; Gisbert & A ; Williot, 1997 ) . Combined eating of unrecorded and manufactured diets, referred to as co-feeding, from the start of exogenic feeding or from an early larval age, could be considered as an alternate scheme.
Mohler et Al ( 2000 ) indicated high endurance in Atlantic sturgeon Acipenser oxyrinchus oxyrinchus utilizing Artemia nauplii and commercial provender. They reported a complete transition to formulated provender with less than 25 % mortality in 20-26 twenty-four hours feeding test. Dilauro et Al ( 1998 ) offered five different formulated diets in combination with unrecorded seawater runt Artemia sp. , to the Lake sturgeon Acipenser fulvescens larvae. They reported no diet consequence ( P a‰¤ 0.05 ) on mean endurance between the groups, but significantly higher growing in fish Federal on merely brine runt. Ware et Al ( 2006 ) investigated the effects of six feeding regimens on the endurance and growing of cultured shortnose sturgeon Fry in 30 yearss feeding governments utilizing formulated diet and cofeeding the unrecorded and formulated provenders. They reported significantly higher endurance and growing in groups co-fed with Artemia compared to populate nutrient and commercial provender entirely. Bardi et Al ( 1998 ) reported higher than 95 % endurance in Mexico sturgeon Acipenser oxyrinchus desotoi larvae when Federal on seawater runt compared to about complete mortality ( & gt ; 99 % ) when fed on formulated provender during a 3 hebdomads feeding tests. Harmonizing to their findings diet-switching experiments revealed that endurance and growing rate of first-feeding larvae increased if they were fed brine runt for 1 hebdomad and so switched to experimental microdiet.
A figure of other surveies have demonstrated the effectivity of co-feeding in heightening the Marine and fresh water larval public presentation beyond that achieved by feeding either types of provenders entirely ( Kanazawa et al. , 1989 ; Holt, 1993 ; Leu et al. , 1991 ; Abi-Ayad and Kestemont, 1994 ; Vega-Orellana et al. , 2006 ; Curnow et al. , 2006b ; Hamza et al. , 2007 ; Rosenlund and Halldorsson, 2007 ) .
The purpose of the present work was to look into how different eating governments, live provender entirely or co-fed with an inert diet, influence the endurance and growing factors in H. huso larvae under controlled research lab conditions.
Eight thousand 3-days old post-hatch yolk-sac larvae of H. huso were obtained from Shahid Marjani Sturgeon Hatchery and transported in oxygenated plastic bags to the Artemia and Aquatic Animals Research Institute, Urmia University. They were so stocked in a large armored combat vehicle incorporating UV-treated belowground fresh water.
Tanks were supplied with UV treated fresh H2O obtained from a well with a flow rate of about 1L/min. Dissolved O was maintained above 7 mg/L utilizing changeless aeration and fish were exposed to a natural photoperiod of about 12:12 L: D. Tanks were flushed daily in the forenoon to take at bay fecal matters. Water temperature was 20 A± 1A°C and pH 7.30-7.50. Temperature, pH and dissolved O were monitored one time or twice daily. No other H2O quality parametric quantities were measured due to the changeless nature of the well H2O quality and high exchange rate of the H2O used in the armored combat vehicles.
After soaking up of their yolk pouch, larvae were transferred to 45 litres polyethylene armored combat vehicles. Two feeding groups were adopted. In the first group the fish larvae were fed on freshly hatched Artemia urmiana nauplii ( N ) for 5 yearss followed by gradual replacing with commercially formulated trout starter diet ( FD ) . Whereas in the 2nd group the fish larvae were fed on different combinations of freshly hatched Artemia nauplii and FD from the first twenty-four hours of exogenic eating. Fish were fed on the footing of 35 % organic structure weight ( first 5 yearss ) , 25 % ( yearss 6-10 ) , 15 % ( yearss 11-15 ) and 10 % organic structure weight ( yearss 16-20 ) severally. Daily rations were divided into six equal repasts and fed at the intervals of four hours. The experiment in both groups was continued for 20 yearss until all feeding interventions were wholly converted to FD in all eating interventions. Survival was monitored every twenty-four hours and zootechnical public presentations ( entire length, wet weight, dry weight, SGR and FCR ) were accessed on yearss 7, 14 and 21 of the experiment harmonizing to standard methods.
Experimental feeding governments:
Artemia nauplii ( N ) throughout the experiment
N for first 5 yearss + 10 % day-to-day replacing of N with FD from twenty-four hours 6 ( entire transition to FD happening on twenty-four hours 15 )
N for first 5 yearss + 30 % replacing of N with FD on twenty-four hours 6 and 10 % day-to-day extra replacing with FD from twenty-four hours 7 ( entire transition to FD happening on twenty-four hours 13 )
N for first 5 yearss + 50 % replacing of N with FD on twenty-four hours 6 and 10 % day-to-day extra replacing with FD from twenty-four hours 7 ( entire transition to FD happening on twenty-four hours 11 )
N ( 90 % provender weight ) and FD ( 10 % provender weight ) on twenty-four hours 1 + 10 % day-to-day replacing of N with FD from twenty-four hours 2 ( entire transition to FD happening on twenty-four hours 10 )
N ( 70 % provender weight ) and formulated provender ( 30 % provender weight ) on twenty-four hours 1 + 10 % day-to-day replacing of N with FD from twenty-four hours 2 ( entire transition to FD happening on twenty-four hours 8 )
N ( 50 % provender weight ) and formulated provender ( 50 % provender weight ) on twenty-four hours 1 + 10 % day-to-day replacing of N with FD from twenty-four hours 2 ( entire transition to FD happening on twenty-four hours 6 )
FD throughout the experiment
The approximative chemical composing of the formulated nutrient and Artemia nauplii used in this survey is shown in table 1.
Table 1: The chemical composing of Artemia nauplii and formulated diet. ( The values indicate the norms values of replicates with standard divergences ) .
Crude protein ( % DW )
Crude lipid ( % DW )
Carbohydrate % DW
Ash ( % )
Energy ( cal.ga?»A? )
50 A± 2
12 A± 1.5
12.5 A± 1
13.5 A± 1
4000 A± 31
61.6 A± 0.8
11.6 A± 2.1
6.8 A± 2
5013.1 A± 88.3
Statistical analysis was carried out utilizing analysis of discrepancy ( ANOVA, SPSS ver 13 ) . Differences between agencies were determined and compared by the Tukey trial. All trials used a significance degree of PA a‰¤A 0.05.
Consequences obtained from the eating experiments are briefly summarized in Tables 2 and 3. Growth of fish was significantly higher in all co-fed groups compared to the fish Federal on merely Artemia nauplii and FD ( P & lt ; 0.05 ) . Fish larvae having 70 % Artemia nauplii and 30 % commercial nutrient on first twenty-four hours followed by 10 % day-to-day replacing with FD ( intervention 6 ) demonstrated maximal growing. Lowest SGR and highest FCR were obtained in fish larvae fed on FD and Artemia nauplii severally ( P & lt ; 0.05 ) . Although SGR was highest in intervention 6, but no statistical differences were observed among different cofeeding groups. We found that feeding H. huso larvae with combination of unrecorded nutrient and FD from the beginning of exogenic eating ( direct passage ) consequences in significantly higher weight addition compared to indirect manner of passage to FD. Very small growing and high mortality ( largely due to cannibalism ) was observed in fish Federal on FD compared to all eating interventions. Significantly greater endurance was observed in the fish Federal on unrecorded nutrient ( 70.6 % ) and in co-fed groups 5 and 6, ( 65.7 % and 59.7 % severally ) compared to angle in other eating interventions. There was no important difference in the endurance of fish fed on unrecorded nutrient and those co-fed with 10 and 30 % FD from the beginning of exogenic eating. It was observed that early co-feeding consequences in higher endurance and weight addition compared to feeding on Artemia nauplii for 5 yearss and gradual shifting to FD. FCR was lower in all passage interventions compared to angle fed on unrecorded nutrient and FD.
Table 2. Initial and concluding length, wet weight and dry weight of H. huso larvae fed on different combinations of unrecorded nutrient and commercial provender. ( Initial sum length, wet weight and dry weight were 25 millimeter, 59 milligram and 10.3 milligrams severally ) .
Concluding length ( millimeter )
Final W. Wt. ( milligram )
Final D. Wt. ( milligram )
57.6 A± 2.8a
1033.9 A± 236.4b
101 A± 43.8b
65.9 A± 2a
1566 A± 192.8c
188.1 A± 33.6c
65.5 A± 2.5b
1568.2 A± 109.1c
194 A± 6.1c
68.3 A± 2.9b
1645.6 A± 201.5c
205.2 A± 25.1c
68.9 A± 1.6b
1702.3 A± 100.4c
210.6 A± 11.7c
69.4 A± 2.2b
1814.5 A± 66.9c
233.4 A± 13.1c
66.2 A± 1.4b
1579.3 A± 115.8c
192.3 A± 13.4c
32.3 A± 2.2a
145.1 A± 15.7a
16.3 A± 3.2a
Different superiors in each column indicate important difference between interventions ( P & lt ; 0.05 ) .
Table 3. Mean SGR, FCR and endurance of Huso huso larvae fed on different combinations of unrecorded nutrient and commercial provender
14.23 A± 1.17b
1.64 A± 0.4b
70.6 A± 3.4d
16.37 A± 0.6c
1.50 A± 0.07a
53.7 A± 2.3bc
16.39 A± 0.3c
1.47 A± 0.01a
50.8 A± 2bc
16.62 A± 0.6c
1.49 A± 0.02a
47.7 A± 3b
16.8 A± 0.3c
1.53 A± 0.03ab
65.7 A± 6.8cd
17.13 A± 0.2c
1.56 A± 0.01ab
59.7 A± 11bcd
16.43 A± 0.36c
1.50 A± 0.04a
52.7 A± 8.8bc
4.5 A± 0.5a
2.66 A± 0.1c
20 A± 2a
Different superiors in each column indicate important difference between interventions ( P & lt ; 0.05 ) .
In most marine species compound diets fed entirely have a hapless ability to prolong fish larvae growing and development ( Canavate and Fernandez-Diaz, 1999 ; Robin and Vincent, 2003 ; Curnow et al. , 2006a ) . The low public presentation normally observed when feeding an inert diet from oral cavity opening to marine fish larvae may be due to sub-optimal diet composing and the larval hapless ability to modulate its digestive enzymes ( Cahu and Zambonino Infante, 2001 ) . Therefore, feeding governments based on a co-feeding scheme have been proposed for farmed species, such as dourado ( Vega-Orellana et al. , 2006 ) , Asiatic sea bass ( Curnow et al. , 2006b ) , pikeperch ( Hamza et al. , 2007 ) , and pod ( Rosenlund and Halldorsson, 2007 ) .
Artemia nauplii are used extensively global as unrecorded nutrient for the larval phases of commercially of import fresh H2O and marine fish species. The cost in substructure, labor and energy to civilization this zooplankton represents a important outgo and the supply and nutritionary quality of seawater runt can change every bit good ( Sorgeloos, 1980 ; Watanabe et al. , 1983 ) . Furthermore it seems that acceptable growing rates in a figure of fish species can non be maintained utilizing unrecorded provender entirely due to the low food content and restricted provenders intake ( Olsen et al. , 1992 ) . This has prompted a great trade of involvement in the development of an unreal larval microdiet ( MD ) as an economic option to populate provenders. However, a lower public presentation is normally reported when inert diets have been fed to larvae from the oncoming of exogenic feeding. They may be due to the composing, palatableness, or physical features of dry provender ( Person Le Ruyet et al. , 1993 ) , or an inability to decently digest the provender ( Holt, 1993 ; Kolkovski et al. , 1993 ; Walford and Lam, 1993 ; Zambonino Infante and Cahu, 1994 ) . But markedly improved public presentation were reported when inert MDs were co-fed with unrecorded zooplankton ( Kanazawa et al. , 1982 ; Szlaminska and Przybyl, 1986 ; Ehrlich et al. , 1989 ; Fermin and Bolivar, 1991 ; Marte and Duray, 1991 ; Tandler and Kolkovski, 1991 ; Walford et al. , 1991 ; Person Le Ruyet et al. , 1993 ; Lavens et al. , 1995 ) .
Use of Artemia nauplii entirely or co-fed with commercial diet at start eating or during early development of different species of sturgeon fish has been reported by a figure research workers ( Dilauro et al. 1998 ; Bardi et Al. 1998 ; Mohler et al. , 2000 ; Volkman et al. 2004 ) .
Consequences obtained in present survey indicated that a carefully programmed usage of unrecorded nutrient co-fed with commercial diet could be successfully used in feeding great sturgeon ( Huso huso ) larvae from first eating phase. The consequences indicated that co-feeding H. huso with unrecorded nutrient and FD from the start eating presented best public presentation back uping the findings of Ware et Al. ( 2006 ) with shortnose sturgeon. Based on their findings, Acipenser brevirostrum exhibited higher endurance and growing in different types of co-feeding regimens compared to populate nutrient regimen. H. huso larvae demonstrated significantly higher growing and endurance when unrecorded nutrient was combined with FD at start feeding compared to passage after 5 yearss initial feeding with unrecorded nutrient. Unlike findings of Dilauro et Al. ( 1998 ) and Bardi et Al. ( 1998 ) , our findings proved that H. huso can readily accept the co-feeding of unrecorded nutrient and FD from first feeding without anterior eating on unrecorded nutrient entirely. H. huso larvae demonstrated high capacity for rapid passage to finish FD within 7 yearss from oncoming of exogenic eating.
It has been proved that co-feeding enhances larval public presentation beyond that achieved by feeding either types of provenders entirely ( Kanazawa et al. , 1989 ; Holt, 1993 ; Leu et al. , 1991 ; Abi-Ayad and Kestemont, 1994 ) , and to allow ablactating in a shorter clip ( Person Le Ruyet et al. , 1993 ) . This determination seems to be true for both H. huso. An increased supply of more suited foods may be the chief consequence of co-feeding on better public presentation of the fish larvae that accepts FD along with unrecorded nutrient. However, the fish larvae suffered significantly high mortality when they were offered merely formulated diet from first eating. It seems that a big figure of larvae dice from famishment, demoing small involvement on formulated diet as exclusive diet. Feeding on FD entirely resulted in high cannibalism in H. huso larvae, turn outing that inert nutrient entirely does non run into all their nutritionary demands at first eating. Apparently there is a specific period during development when different sturgeon fish larvae will eat manufactured diets and this seems to be related to their behavioral and physiological capacity. It seems that successful co-feeding depends on the ability of the fish larvae to eat dry provender when unrecorded provender is besides present.
It is concluded that H. huso larvae could be co-fed with a combination of Artemia nauplii and commercial provender from oncoming of exogenic feeding with rapid entire transition to FD within 7 yearss. Co-feeding resulted in considerable decrease of consumable costs ( including Artemia cyst ) , stuffs, forces and infinite needed for readying of provender and eating procedure. Co-feeding in H. huso seems to function two intents ; it improves and stabilizes the nutritionary status of the larvae and it pre-conditions the larvae to accept the manufactured diet when the unrecorded nutrient is withdrawn, ensuing in a shorter ablactating period.
This survey was carried out with the fiscal support of the Artemia and Aquatic Animals Research Institute, Urmia University, Iran.