Transcript
Page 1: Transfering Vitamin C from fish to embryos

May | June 2012

Feature title: Transfering Vitamin C from fish to embryos

The International magazine for the aquaculture feed industry

International Aquafeed is published five times a year by Perendale Publishers Ltd of the United Kingdom.All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. ©Copyright 2012 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1464-0058

Page 2: Transfering Vitamin C from fish to embryos

Beneficial effects of ascorbic acid supplementation to broodstock of a select aquaculture species is well documented. At the present levels

of feeding, dietary means of vitamin C does not meet the requirements for maturation, reproduction and needs of early life stages of larvae.

In addition, this nutrient is water soluble and readily gets accumulated by other organs before reaching the ovary. For practical reasons, it is not possible to attain the desired level of a nutrient by

conventional methods, hence innovative approaches are needed. Mass transfer of nutrients via injection into broodstock is a novel method.

Two routes of maternal transfer of vitamin C in mature channel catfish (Ictalurus punc-tatus) prior to hormone-induced spawning were explored as a strategy to incorporate

the vitamin and to determine its effect on reproduction and progeny performance.

The results of this study suggest injecting vitamin C prior to hormone-induce spawning, invokes transfer to eggs, improves repro-

ductive performance, and may subsequently improve ontogeny performance.

However, the effect of vitamin C dimin-ished with age and also in more natural condi-tions. Our goal was to achieve predictable fish production of robust quality for healthy, efficient, higher surviving and able to adapt to common stressors and pathogens.

Improvements can be made in this area by new knowledge-based advances in nutrient deliv-ery systems that may create large improvements in terms of produc-tion, feed conversion and survival in aquaculture production.

Importance of vitamin CAscorbic acid is an essential

micronutrient in the diet of teleost fish, which do not have gulonol-actone oxidase activity. Vitamin C is needed for post-translato-ry hydroxylation of proline and lysine moieties in collagen, min-eral metabolism to improve stress response and immunity, detoxifica-tion reactions, steroid synthesis and vitellogenesis.

Egg ascorbic acid deposition levels may easily be tailored by feeding broodfish with elevated levels of ascorbic acid before and after vitellogenesis. The accumula-tion of essential nutrients in eggs is dependent on the nutrient reserves in the female fish and therefore on the dietary intake of broodfish in the period preceeding and during gametogenesis. Hence, broodfish nutrition consisting of

essential nutrients is important. The earliest steps in embryonic develop-

ment are dependent on and driven by mater-nal factors deposited in the oocyte during oogenesis. Maternal factors are stored in the

Table 1: Mass transfer of Vitamin C from broodfish to eggs/embryos

SpeciesMass trasfer strategy Dose Reference

Rainbow trout Diet 1000 mg/Kg Sandness et al. (1984)

Oncorhynchus mykiss

Tilapia Diet 1250 mg/Kg Soliman et al. (1986)

Oreochromis mossambicus

Atlantic Cod Diet 500 mg/Kg Mangor-Jensen et al. (1994)

Gadus morhua

Rainbow trout Diet 500 mg/Kg Blom and Dabrowski (1995)

Oncorhynchus mykiss

Channel catfish Diet 500 mg/Kg Zuberi et al. (2011)

Ictalurus punctatus

Rainbow trout Immersion 1000 mg/L Falhatkar et al. (2006)

Oncorhynchus mykiss

Rainbow trout Immersion and Diet 1000 and 500 mg/Kg Falhatkar el.al. (2011)

Oncorhynchus mykiss

Japanese eel Injecting broodfish 50 mg/Kg Yoshikawa, 1998

Anguilla japonica

Japanese eel Injecting broodfish 1mL* /Kg Furuita et al. 2009

Anguilla japonica

Channel catfish Injecting broodfish 1 mL*/Kg Chatakondi et al. 2010

Ictalurus punctatus

*Vitamin emulsion was prepared by dissolving Sodium Ascorbate in 0.9% NaCl Solution

Transfering

by Nagaraj G. Chatakondi PhD, National Warmwater Aquaculture Center, USA

Vitamin Cfrom fish

to embryos

8 | InternatIonal AquAFeed | May-June 2012

FEATURE

May-June 2012 | InternatIonal AquAFeed | 9

IAF12.03.indd 8 14/05/2012 18:06

form of specific mRNAs, proteins, hormones and other biomolecules. At egg activation and fertilization, these factors become available for embryogenesis, sometimes after a process of activation involving translation or protein modification.

It has been documented that vitamin C or ascorbic acid deficiency in larval fish has been associated with hyperplasia of collagen and cartilage, scoliosis, lordosis, internal hemor-rhages, resorbed opercules and abnormal support cartilage in gills, spine and fins with deformities of the jaw and snout.

Based on recent research, vitamin C needs for reproduction and early life stages of fish are 10 times the recommended dose for rais-ing young adult fish. These high levels cannot be met by dietary administration to broodfish because the nutrient is water soluble and readily absorbed / utilized by other organs during oocyte development.

It has been demonstrated in several species that nutrients in broodfish diet are transferred to oocytes through uptake of extra-ovarian substances from the maternal blood. Also, there was up to a 82.4 percent loss of ascor-bic acid of the prepared commercial diet. A 3.8 – 8.3-fold increase of vitamin C in the diet generally results in 56 to 71.9 percent increase of total ascorbic acid in the eggs respectively.

The fry produced from par-ents fed with elevated levels of vitamin C tend to have higher growth performance as compared with control groups. Thus, there is a need in enhance ascorbic acid in the broodfish. A diet with vitamin C content adequate for normal growth may not be sufficient for broodfish when the goal is to transfer ascorbic acids to embryos.

Reproduction and arval performance

Broodfish diet has a major influence on fecundity and egg quality. It has also been demonstrat-ed that the nutritional status of broodfish can affect offspring quality. The accumulation of essential nutrients in eggs is dependent on 1) the nutrient reserves in the female fish and 2) the dietary intake preceding gonadogenesis. Vitamin C is needed for maturation, repro-duction and larval metamorphosis. Beneficial effects include increased fertility, fecundity and egg quality.

Nutrients in broodfish diet are trans-

ferred to oocytes through uptake of extra-ovarian substances from the maternal blood. Immersion enrichment of eggs is another approach to introduce compounds and nutri-ents into eggs. Immersion enrichment fol-lowed by feeding fry with vitamin C enhanced feed was also found to be an effective method.

Injecting vitamin C in to broodfish during artificial- induced maturation improved repro-duction and progeny performance. Efforts are

"Based on 2011 data, approximately 335

million pounds of catfish were processed,

a reduction of over 50 percent compared

to the best production in 2003

8 | InternatIonal AquAFeed | May-June 2012 May-June 2012 | InternatIonal AquAFeed | 9

FEATURE

SPA

NIS

HLA

NG

UA

GE

EDIT

ION

http://www.aquafeed.co.uk/edicion-espanola

EDICIONESPANOLA

Providing proficient tools to achieve cost-effective and sustainable aquaculture practices

ECOBIOL Aquaa highly effective single strain probiotic

GUSTOR Aquaa natural growth promoter

BIOMET Aquaan organic mineral source

NOREL,S.A. • Jesús Aprendiz, 19, 1º A y B • 28007 Madrid (SPAIN)Tel. +34 91 501 40 41 • Fax +34 91 501 46 44 • www.norel.es

Natural nutr

ition

AN. REV. 90X132.indd 1 02/08/11 13:13

IAF12.03.indd 9 14/05/2012 18:06

Page 3: Transfering Vitamin C from fish to embryos

Beneficial effects of ascorbic acid supplementation to broodstock of a select aquaculture species is well documented. At the present levels

of feeding, dietary means of vitamin C does not meet the requirements for maturation, reproduction and needs of early life stages of larvae.

In addition, this nutrient is water soluble and readily gets accumulated by other organs before reaching the ovary. For practical reasons, it is not possible to attain the desired level of a nutrient by

conventional methods, hence innovative approaches are needed. Mass transfer of nutrients via injection into broodstock is a novel method.

Two routes of maternal transfer of vitamin C in mature channel catfish (Ictalurus punc-tatus) prior to hormone-induced spawning were explored as a strategy to incorporate

the vitamin and to determine its effect on reproduction and progeny performance.

The results of this study suggest injecting vitamin C prior to hormone-induce spawning, invokes transfer to eggs, improves repro-

ductive performance, and may subsequently improve ontogeny performance.

However, the effect of vitamin C dimin-ished with age and also in more natural condi-tions. Our goal was to achieve predictable fish production of robust quality for healthy, efficient, higher surviving and able to adapt to common stressors and pathogens.

Improvements can be made in this area by new knowledge-based advances in nutrient deliv-ery systems that may create large improvements in terms of produc-tion, feed conversion and survival in aquaculture production.

Importance of vitamin CAscorbic acid is an essential

micronutrient in the diet of teleost fish, which do not have gulonol-actone oxidase activity. Vitamin C is needed for post-translato-ry hydroxylation of proline and lysine moieties in collagen, min-eral metabolism to improve stress response and immunity, detoxifica-tion reactions, steroid synthesis and vitellogenesis.

Egg ascorbic acid deposition levels may easily be tailored by feeding broodfish with elevated levels of ascorbic acid before and after vitellogenesis. The accumula-tion of essential nutrients in eggs is dependent on the nutrient reserves in the female fish and therefore on the dietary intake of broodfish in the period preceeding and during gametogenesis. Hence, broodfish nutrition consisting of

essential nutrients is important. The earliest steps in embryonic develop-

ment are dependent on and driven by mater-nal factors deposited in the oocyte during oogenesis. Maternal factors are stored in the

Table 1: Mass transfer of Vitamin C from broodfish to eggs/embryos

SpeciesMass trasfer strategy Dose Reference

Rainbow trout Diet 1000 mg/Kg Sandness et al. (1984)

Oncorhynchus mykiss

Tilapia Diet 1250 mg/Kg Soliman et al. (1986)

Oreochromis mossambicus

Atlantic Cod Diet 500 mg/Kg Mangor-Jensen et al. (1994)

Gadus morhua

Rainbow trout Diet 500 mg/Kg Blom and Dabrowski (1995)

Oncorhynchus mykiss

Channel catfish Diet 500 mg/Kg Zuberi et al. (2011)

Ictalurus punctatus

Rainbow trout Immersion 1000 mg/L Falhatkar et al. (2006)

Oncorhynchus mykiss

Rainbow trout Immersion and Diet 1000 and 500 mg/Kg Falhatkar el.al. (2011)

Oncorhynchus mykiss

Japanese eel Injecting broodfish 50 mg/Kg Yoshikawa, 1998

Anguilla japonica

Japanese eel Injecting broodfish 1mL* /Kg Furuita et al. 2009

Anguilla japonica

Channel catfish Injecting broodfish 1 mL*/Kg Chatakondi et al. 2010

Ictalurus punctatus

*Vitamin emulsion was prepared by dissolving Sodium Ascorbate in 0.9% NaCl Solution

Transfering

by Nagaraj G. Chatakondi PhD, National Warmwater Aquaculture Center, USA

Vitamin Cfrom fish

to embryos

8 | InternatIonal AquAFeed | May-June 2012

FEATURE

May-June 2012 | InternatIonal AquAFeed | 9

IAF12.03.indd 8 14/05/2012 18:06

form of specific mRNAs, proteins, hormones and other biomolecules. At egg activation and fertilization, these factors become available for embryogenesis, sometimes after a process of activation involving translation or protein modification.

It has been documented that vitamin C or ascorbic acid deficiency in larval fish has been associated with hyperplasia of collagen and cartilage, scoliosis, lordosis, internal hemor-rhages, resorbed opercules and abnormal support cartilage in gills, spine and fins with deformities of the jaw and snout.

Based on recent research, vitamin C needs for reproduction and early life stages of fish are 10 times the recommended dose for rais-ing young adult fish. These high levels cannot be met by dietary administration to broodfish because the nutrient is water soluble and readily absorbed / utilized by other organs during oocyte development.

It has been demonstrated in several species that nutrients in broodfish diet are transferred to oocytes through uptake of extra-ovarian substances from the maternal blood. Also, there was up to a 82.4 percent loss of ascor-bic acid of the prepared commercial diet. A 3.8 – 8.3-fold increase of vitamin C in the diet generally results in 56 to 71.9 percent increase of total ascorbic acid in the eggs respectively.

The fry produced from par-ents fed with elevated levels of vitamin C tend to have higher growth performance as compared with control groups. Thus, there is a need in enhance ascorbic acid in the broodfish. A diet with vitamin C content adequate for normal growth may not be sufficient for broodfish when the goal is to transfer ascorbic acids to embryos.

Reproduction and arval performance

Broodfish diet has a major influence on fecundity and egg quality. It has also been demonstrat-ed that the nutritional status of broodfish can affect offspring quality. The accumulation of essential nutrients in eggs is dependent on 1) the nutrient reserves in the female fish and 2) the dietary intake preceding gonadogenesis. Vitamin C is needed for maturation, repro-duction and larval metamorphosis. Beneficial effects include increased fertility, fecundity and egg quality.

Nutrients in broodfish diet are trans-

ferred to oocytes through uptake of extra-ovarian substances from the maternal blood. Immersion enrichment of eggs is another approach to introduce compounds and nutri-ents into eggs. Immersion enrichment fol-lowed by feeding fry with vitamin C enhanced feed was also found to be an effective method.

Injecting vitamin C in to broodfish during artificial- induced maturation improved repro-duction and progeny performance. Efforts are

"Based on 2011 data, approximately 335

million pounds of catfish were processed,

a reduction of over 50 percent compared

to the best production in 2003

8 | InternatIonal AquAFeed | May-June 2012 May-June 2012 | InternatIonal AquAFeed | 9

FEATURE

SPA

NIS

HLA

NG

UA

GE

EDIT

ION

http://www.aquafeed.co.uk/edicion-espanola

EDICIONESPANOLA

Providing proficient tools to achieve cost-effective and sustainable aquaculture practices

ECOBIOL Aquaa highly effective single strain probiotic

GUSTOR Aquaa natural growth promoter

BIOMET Aquaan organic mineral source

NOREL,S.A. • Jesús Aprendiz, 19, 1º A y B • 28007 Madrid (SPAIN)Tel. +34 91 501 40 41 • Fax +34 91 501 46 44 • www.norel.es

Natural nutr

ition

AN. REV. 90X132.indd 1 02/08/11 13:13

IAF12.03.indd 9 14/05/2012 18:06

Page 4: Transfering Vitamin C from fish to embryos

Volume 15 / Issue 3 / May-June 2012 / © Copyright Perendale Publishers Ltd 2012 / All rights reserved

WHO CARES...…If profits in the aquaculture industry are as appetising as a sea bass dinner?

As feed prices soar and formulation moves towards sustainability, aquaculture producers must maximise feed efficiency to stay on the menu.

In all phases of the fish’s life, proper nutrition will improve health. With decades of dedicated research, the “Alltech Aqua Advantage” programme responds to the challenges of today’s aquaculture producers

through nutritional innovation, addressing issues such as growth and performance, feed efficiency, flesh quality and immunity.

So, when asked who cares about your profitability? Remember

DOES!

alltech.com | facebook.com/AlltechNaturally | @Alltech

Silver Sponsor of

XV International Symposium on Fish Nutrition and Feeding

Molde, Norway • 4-7 June 2012

IAF12.03.indd 2 14/05/2012 18:05

Page 5: Transfering Vitamin C from fish to embryos

Volume 15 / Issue 3 / May-June 2012 / © Copyright Perendale Publishers Ltd 2012 / All rights reserved

WHO CARES...…If profits in the aquaculture industry are as appetising as a sea bass dinner?

As feed prices soar and formulation moves towards sustainability, aquaculture producers must maximise feed efficiency to stay on the menu.

In all phases of the fish’s life, proper nutrition will improve health. With decades of dedicated research, the “Alltech Aqua Advantage” programme responds to the challenges of today’s aquaculture producers

through nutritional innovation, addressing issues such as growth and performance, feed efficiency, flesh quality and immunity.

So, when asked who cares about your profitability? Remember

DOES!

alltech.com | facebook.com/AlltechNaturally | @Alltech

Silver Sponsor of

XV International Symposium on Fish Nutrition and Feeding

Molde, Norway • 4-7 June 2012

IAF12.03.indd 2 14/05/2012 18:05

Innovations for a better world.

Bühler AG, Feed & Biomass, CH-9240 Uzwil, Switzerland, T +41 71 955 11 11, F +41 71 955 28 96

[email protected], www.buhlergroup.com

Fatten up your bottom line. Bühler high-performance animal and aqua feed production

systems are used by leading companies around the world. These producers know they

can rely not just on the technology itself, but also on the support that accompanies it. A

service combining local presence with global expertise both lowers feed mill operating

costs and increases capacity utilization. To find out more, visit www.buhlergroup.com

Aqua_Feed-July_2011.indd 1 28.07.2011 12:23:44IAF12.03.indd 50 14/05/2012 18:10

Page 6: Transfering Vitamin C from fish to embryos

10 | InternatIonal AquAFeed | May-June 2012

No hollow spaces | No cross contaminationExcellent cleaning access | Filtered air inletTemperature control | Moisture control | Cleaning in Place

C L E A N C O N T R O L

Swivel Valve Cooler MkII

c o o l a n d d r y

clean and lean

[email protected]

www.geelencounterflow.com

T +31-475-592315

Geelen Counterflow Holland / USA / Argentina / China

IAF12.03.indd 11 14/05/2012 18:06

underway to develop procedures to effec-tively and stably accumulate vitamin C in eggs by broodstock injections (Table 1).

Vitamin C needs of channel catfish

Channel catfish is the single largest aquaculture fish species cultured in the

United States. Based on 2011 data, approximately 335 million pounds of cat-fish were processed, a reduction of over 50 percent compared to the best produc-tion in 2003 (2012 USDA NASS). The industry is currently struggling to keep pace with the increasing cost of feed, fuel, production inefficiencies, foreign imports and economy. Adopting hybrid catfish (channel catfish female x blue catfish, I.

furcatus male), hybridisation can be used to improve productivity immediately by producing fish that exhibit hybrid vigor.

Based on numerous laboratory and field trials, hybrid catfish are superior in growth rate, feed conversion, survival, seinability and processing traits compared to commonly raised channel catfish.

A decade ago, produc-ing commercial quanti-ties of hybrid catfish was believed to be unattain-able. Natural hybridisation is rare and artificial spawn-ing of channel catfish has been historically low and with no effective ovulating agents available.

However, in the last 10 years, consistent and marked improvements were made in all the phases of artificial spawn-ing and the hatchery pro-duction of hybrid catfish embryos. Improved pro-duction and consistent superior performance of hybrid catfish in commer-cial earthen production ponds has rejuvenated

the industry with unprecedented optimism. Presently, a third of catfish farmers raise hybrid catfish in production ponds and hybrid catfish account for approximately 25 percent of all the total catfish processed in 2011.

Our goal is to achieve predictable fish production of robust quality for healthy, fast growing, survival and adapt to common stressors and pathogens and to varying envi-ronmental conditions. Improvements can be

made in this area by new knowledge-based advances in live food production or nutri-ent delivery systems that may create large improvements in terms of production, survival and processing yield.

Preliminary findings Broodstock preparation is the primary

requisite for hormone-induced spawning of channel catfish in the production of channel x blue hybrid catfish. Hence, broodfish manage-ment techniques must be geared towards attaining maximum production of high-quality eggs and larvae because variable egg quality is one of the limiting factors in fish hatcher-ies. Broodstock diet has been considered as one of the factors affecting fecundity, egg, and larval quality in fish. The accumulation of essential nutrients in eggs are dependent on the nutrient reserves in the female fish, and consequently on the dietary nutrient input of broodstock in the period preceding gonadogenesis. When eggs absorb water, it is possible to introduce compounds such as vitamins and minerals into the eggs with the water solution before water hardening.

It was hypothesised that injecting female broodfish prior to hormone-induced spawn-ing would result in mass transfer of nutrients to improve maturation, ovulation, and subse-quent progeny performance. Preliminary stud-ies confirmed accumulation of vitamin C in ovarian tissue and invoked a positive response to ovulation, fecundity and egg quality. Mass transfer of vitamin C to the eggs improved growth and reduced mortalities following Edwardseilla ictaluri disease challenge.

It appears that mass transfer of vitamin C to eggs is attained by injecting broodfish prior to hormone-induced spawning to improve progeny performance. ■

"A decade ago, producing commercial quantities of hybrid

catfish was believed to be unattainable.

- Presently, a third of catfish farmers raise hybrid catfish in production ponds and hybrid

catfish account for approximately 25% of all the total catfish processed in 2011"

"It appears that mass transfer of vitamin C

to eggs is attained by injecting broodfish

prior to hormone-induced spawning

to improve progeny performance"

10 | InternatIonal AquAFeed | May-June 2012

FEATURE

No hollow spaces | No cross contaminationExcellent cleaning access | Filtered air inletTemperature control | Moisture control | Cleaning in Place

C L E A N C O N T R O L

Swivel Valve Cooler MkII

c o o l a n d d r y

clean and lean

[email protected]

www.geelencounterflow.com

T +31-475-592315

Geelen Counterflow Holland / USA / Argentina / China

IAF12.03.indd 10 14/05/2012 18:06

Page 7: Transfering Vitamin C from fish to embryos

10 | InternatIonal AquAFeed | May-June 2012

No hollow spaces | No cross contaminationExcellent cleaning access | Filtered air inletTemperature control | Moisture control | Cleaning in Place

C L E A N C O N T R O L

Swivel Valve Cooler MkII

c o o l a n d d r y

clean and lean

[email protected]

www.geelencounterflow.com

T +31-475-592315

Geelen Counterflow Holland / USA / Argentina / China

IAF12.03.indd 11 14/05/2012 18:06

underway to develop procedures to effec-tively and stably accumulate vitamin C in eggs by broodstock injections (Table 1).

Vitamin C needs of channel catfish

Channel catfish is the single largest aquaculture fish species cultured in the

United States. Based on 2011 data, approximately 335 million pounds of cat-fish were processed, a reduction of over 50 percent compared to the best produc-tion in 2003 (2012 USDA NASS). The industry is currently struggling to keep pace with the increasing cost of feed, fuel, production inefficiencies, foreign imports and economy. Adopting hybrid catfish (channel catfish female x blue catfish, I.

furcatus male), hybridisation can be used to improve productivity immediately by producing fish that exhibit hybrid vigor.

Based on numerous laboratory and field trials, hybrid catfish are superior in growth rate, feed conversion, survival, seinability and processing traits compared to commonly raised channel catfish.

A decade ago, produc-ing commercial quanti-ties of hybrid catfish was believed to be unattain-able. Natural hybridisation is rare and artificial spawn-ing of channel catfish has been historically low and with no effective ovulating agents available.

However, in the last 10 years, consistent and marked improvements were made in all the phases of artificial spawn-ing and the hatchery pro-duction of hybrid catfish embryos. Improved pro-duction and consistent superior performance of hybrid catfish in commer-cial earthen production ponds has rejuvenated

the industry with unprecedented optimism. Presently, a third of catfish farmers raise hybrid catfish in production ponds and hybrid catfish account for approximately 25 percent of all the total catfish processed in 2011.

Our goal is to achieve predictable fish production of robust quality for healthy, fast growing, survival and adapt to common stressors and pathogens and to varying envi-ronmental conditions. Improvements can be

made in this area by new knowledge-based advances in live food production or nutri-ent delivery systems that may create large improvements in terms of production, survival and processing yield.

Preliminary findings Broodstock preparation is the primary

requisite for hormone-induced spawning of channel catfish in the production of channel x blue hybrid catfish. Hence, broodfish manage-ment techniques must be geared towards attaining maximum production of high-quality eggs and larvae because variable egg quality is one of the limiting factors in fish hatcher-ies. Broodstock diet has been considered as one of the factors affecting fecundity, egg, and larval quality in fish. The accumulation of essential nutrients in eggs are dependent on the nutrient reserves in the female fish, and consequently on the dietary nutrient input of broodstock in the period preceding gonadogenesis. When eggs absorb water, it is possible to introduce compounds such as vitamins and minerals into the eggs with the water solution before water hardening.

It was hypothesised that injecting female broodfish prior to hormone-induced spawn-ing would result in mass transfer of nutrients to improve maturation, ovulation, and subse-quent progeny performance. Preliminary stud-ies confirmed accumulation of vitamin C in ovarian tissue and invoked a positive response to ovulation, fecundity and egg quality. Mass transfer of vitamin C to the eggs improved growth and reduced mortalities following Edwardseilla ictaluri disease challenge.

It appears that mass transfer of vitamin C to eggs is attained by injecting broodfish prior to hormone-induced spawning to improve progeny performance. ■

"A decade ago, producing commercial quantities of hybrid

catfish was believed to be unattainable.

- Presently, a third of catfish farmers raise hybrid catfish in production ponds and hybrid

catfish account for approximately 25% of all the total catfish processed in 2011"

"It appears that mass transfer of vitamin C

to eggs is attained by injecting broodfish

prior to hormone-induced spawning

to improve progeny performance"

10 | InternatIonal AquAFeed | May-June 2012

FEATURE

No hollow spaces | No cross contaminationExcellent cleaning access | Filtered air inletTemperature control | Moisture control | Cleaning in Place

C L E A N C O N T R O L

Swivel Valve Cooler MkII

c o o l a n d d r y

clean and lean

[email protected]

www.geelencounterflow.com

T +31-475-592315

Geelen Counterflow Holland / USA / Argentina / China

IAF12.03.indd 10 14/05/2012 18:06

Page 8: Transfering Vitamin C from fish to embryos

www.aquafeed.co.uk

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• ContacttheInternationalAquafeedTeam

• SubscribetoInternationalAquafeed

VOLUME 15 I S SUE 3 2 012

THE INTERNATIONAL MAGAZINE FOR THE AQUACULTURE FEED INDUSTRY

Transfering Vitamin C from fish to embryos

Oxygenation technology– poised to transform aquaculture worldwide

Ornamental fish and invertebrates for home aquaria

Brewers’ yeast as a supplement in aquaculture

IAF12.03.indd 1 14/05/2012 18:05

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