Engormix
Login o register me

Broodstock and larval nutrition in successful aquaculture

Feeds for the future: the importance of better broodstock and larval nutrition in successful aquaculture

Published on:
Author/s :
(4405)
(7)

Introduction

The future of aquaculture production, as in other animal production systems, is towards greater control of the physical, chemical and biological variables surrounding the production system. The trend from collection of wild fry to the development of hatcheries for fry production, from the use of wild spawners to the use of maturation systems and ultimately closing the reproductive cycle to use domesticated and selected stocks is clear. At the same time, there is an increasing trend towards production efficiency and cost-effectiveness, not least in the hatchery stage, particularly where the supply – demand situation progresses from quantity production to quality production. These trends are becoming more evident in all forms of commercial aquaculture.

Broodstock and larval nutrition are key elements underpinning this progress towards greater control and domestication. However, there is substantial work to be done if rearing of aquaculture species is to approach the level of control and understanding which are evident in the poultry, swine and ruminant sectors.

This paper gives a brief introduction to some of the key areas and issues in broodstock and larval nutrition.

Constraints of time and space mean that the paper is largely confined to crustacean, and particularly, penaeid shrimp culture. However, many of the same gaps are found when looking at the broodstock and larval nutrition of most fish species.


Broodstock nutrition

Research into shrimp broodstock nutrition is gaining importance with the increasing use of domesticated and genetically selected stocks for aquaculture. Also,given the high cost of feed in a captive broodstock maturation facility, estimated at around 50% of total cost, as well as a heavy reliance on fresh feed items such as squid, mollusk meals and polychaete worms which may vary in quality and availability, there is a demand for feeds specifically formulated for use in maturation diets. It has also been pointed out (Doyle, personal communication) that the development of genetically improved lines of shrimp may benefit from a simultaneous development of feeds specifically tailored to individual strain requirements.

During penaeid shrimp maturation, nutrient reserves, mainly from the hepatopancreas, are mobilised to support ovarian and testicular maturation, gametogenesis and vitellogenesis (Harrison, 1990; 1997). Tissue reserves in the hepatopancreas can be depleted rapidly so that the diet becomes the most important contributor of nutrients to the developing egg.

This is particularly true when, as is the case in most captive maturation facilities, eyestalk ablation is used to accelerate the process of gonadal maturation. The hormonal and metabolic changes that come around during such forced maturation may take place when the nutrient reserves are insufficient to support rapid ovarian development placing an even larger burden on the diet as a source of essential nutrients.

The nutrition of penaeid shrimp broodstock has recently been reviewed (Wouters et al., 2001a). The authors recognize that there is a dearth of information in the scientific literature on the subject, possibly due to the expense and complexity of running sufficiently rigorous nutrition experiments on shrimp broodstock. In addition, much of the research has been carried out with fresh feeds, either alone or in combination with formulated diets or dietary supplements.


LIPIDS

Due to the importance of lipids in crustacean maturation, much of the work carried out to date has focused on this aspect, particularly the requirement for highly unsaturated fatty acids (HUFA) and phospholipid. During maturation, lipids are mobilized from the hepatopancreas in many species and dietary lipids rapidly processed for transport to the developing ovaries.

Total lipid does not appear to be important although Wouters et al. (2001b) reported that excessively high total lipid in the diet had an adverse effect on ovarian maturation and feed consumption, possibly due to satiation. However, the average lipid level in commercial broodstock diets (10%) appears to be around 3% higher than in grower feeds used in commercial culture ponds.

Highly unsaturated fatty acids (HUFA), especially 20:5n-3 and 22:6n-3, are abundant in ovarian tissues and are believed to be an important component of live and formulated maturation diets. Diets deficient in n-3 HUFA have been found to have a negative effect on ovarian development, fecundity and egg quality (Teshima et al., 1988; Alava et al., 1993; Xu et al., 1992; 1994; Cahu et al., 1994; Wouters et al., 1999a).

Arachidonic acid (20:4n-6; AA) has been detected at high levels in the ovaries of wild shrimp and is also abundant in some of the best fresh feed items such as polychaetes (bloodworms), clams and mussels (Harrison, 1997; Wouters et al., 2001a). The n-6 HUFA are known to be precursors of the prostaglandin hormones, which act in reproduction and vitellogenesis. According to Wouters et al. (2001a), formulated maturation diets appear to be deficient in AA as well as relatively low eicosapentanoic acid (EPA) levels. It has been proposed that the ratio of n-3 to n-6 levels in the diet is important (Lytle et al., 1990) and that it should be around 2–3 to 1 (Ravid et al., 1999; Wouters et al., 1999b).

Phospholipids, mainly phosphatidylcholine and phosphatidylethanolamine appear to be predominant in the shrimp ovary and there seems to be a requirement for phospholipids in the diet. Several studies (Alava et al., 1993; Cahu et al., 1994; Ravid et al., 1999; Wouters et al., 1999b) have demonstrated the effects of phospholipid levels in the diet and it has been suggested that broodstock diets should contain more than 2% phospholipid to ensure that 50% of total egg lipid is in this form (Cahu et al., 1994).

Cholesterol is the precursor of steroid hormones and it is known that shrimp have a requirement for cholesterol in the diet. Cholesterol is stored in the hepatopancreas and is mobilized during maturation. The role and mobilization of cholesterol during shrimp maturation has been reviewed by Harrison (1990). Some of the live feed organisms used in maturation diets have relatively high cholesterol levels (e.g. squid, clams) although to date there has been limited research into the effects of dietary cholesterol on maturation and reproduction (Harrison, 1997; Wouters, 2001).

During maturation, the level of triacylglycerides (TAG) in the ovaries increases as they are incorporated into the egg and decrease after spawning (Ravid et al., 1999; Wouters et al., 1999b). Triacylglycerides appear to be the principal energy source in eggs and nauplii and their importance in reproduction, and egg and postlarval quality has been shown (Palacios et al., 1998; 1999).


PROTEIN AND AMINO ACIDS

Maturation is a time of intense protein synthesis and it is likely that the requirement for protein is higher at this time (Harrison, 1990; 1997). Wouters et al. (2001a) report that the protein content of formulated diets in their studies was around 50% but that this was still low compared to the level in fresh feeds.

Detailed studies into protein requirements for shrimp broodstock are still lacking and it has been proposed that the amino acid profiles should mimic those found in fresh feeds (Deshimaru, 1982).

Some studies have shown changes in protein content of the ovaries associated with egg development and spawning, and with spawning success. Animulkar (1980), reported in Harrison (1997), found an increase in ovarian protein levels associated with ovarian development followed by a sharp decrease after spawning in the shrimp Paratelphysa hydrodromaus and several authors have noted a similar increase in farmed penaeid shrimp (Read and Caulton, 1980; Castille and Lawrence, 1989). A marked difference has also been noted in the protein content of the hepatopancreas and ovaries of wild and domesticated females of Litopenaeus vannamei with good repeat spawning performance which have been found to have significantly higher protein content than females with poorer spawning performance (Palacios et al., 2000).


CARBOHYDRATES

Carbohydrates do not appear to be essential for shrimp broodstock diets although Palacios et al. (1998; 1999)
related egg glucose levels with larval quality and broodstock condition. Carbohydrates can be used as cost-effective ingredients to contribute to glycogen accumulation in the hepatopancreas (Harrison, 1997) as well as providing other benefits in the broodstock diet, acting as binders and possibly playing a role in transport of nutrients in the hemolymph (Harrison, 1997).


VITAMINS AND MINERALS

Detailed vitamin and mineral requirements for shrimp broodstock diets are relatively unknown with only a few studies on vitamins A, C and E. Alava et al. (1993) found that ovarian maturation was slower when fed a diet deficient in either vitamins E, A and C. Vitamin E appears to be important in crustacean broodstock nutrition.

Chamberlain (1988), reported in Harrison (1997), found a correlation between vitamin E deficiency and the percentage of abnormal sperm in Litopenaeus setiferus and Cahu et al. (1991) found an improvement in hatching rate with increasing dietary vitamin E correlated to increasingα−tocopherol levels in the egg.

Wouters et al. (1999b) found a similar correlation to that observed by Cahu et al. (1991) between spawn and hatch quality with α-tocopherol levels in wild spawners and nauplii of L. vannamei. They found that mature
ovaries and nauplii contained higher levels of α−tocopherol than immature and spent ovaries. Harrison (1997) also speculated that vitamin E in the egg yolk may also act as a natural antioxidant.

Work conducted by Fisher and Kon (1958), reported in Harrison (1997), suggested the importance of dietary vitamin A due to its accumulation in the ovaries of crustaceans during maturation. Vitamin C content of eggs of Fenneropenaeus indicus are also influenced by the levels in the diet, and high hatching rate has been related to high ascorbic acid levels in the eggs (Cahu et al., 1995). Harrison (1997) assumes that vitamin D is important in broodstock diets due to its probable role in calcium and phosphorus metabolism in crustaceans.

Harrison (1990) discussed the possibility that mineral deficiencies or imbalances could have a negative impact on crustacean reproduction and may play a role in oocyte resorption, reduction in reproductive performance and egg quality. Studies into mineral requirements are rare due to several complications (Wouters et al., 2001a). Where studies have been conducted, diets were formulated with mineral mixes with added calcium, phosphorus, magnesium, sodium, iron, manganese and selenium (Chamberlain, 1988; Marsden et al., 1997; Mendoza et al., 1997; Xu et al., 1994).

Spent broodstock of L. vannamei had lower levels of calcium and magnesium in the muscle and lower magnesium levels in the hepatopancreas (Mendez et al., 1997), possibly due to a combination of dietary deficiencies and losses through moulting and transfer to the eggs. Copper also decreased in the hepatopancreas, possibly through transfer to the ovaries, although it increased in the muscle tissue. It is clear that more studies need to be undertaken into mineral nutrition in broodstock diets.


CAROTENOIDS

Crustaceans cannot synthesise carotenoids de novo, and a dietary source of these pigments is required. During sexual maturation, most crustaceans accumulate carotenoids in the hepatopancreas and during vitellogenesis, these are transported in the hemolymph as carotenoglycolipoproteins to accumulate in the eggs as part of the lipovitellin protein. Dall (1995) found that free astaxanthin levels in the developing ovaries of Penaeus esculentus increased from 2 to 34 ppm and in the digestive gland, from 20 to 120 ppm.

Carotenoids, especially astaxanthin, are strong antioxidants and probably play a role in protecting the broodstock nutrient reserves and developing embryos from oxidation (Dall et al., 1995; Merchie et al., 1998). It has also been suggested (Harrison, 1997) that they act as pigment reserves in the embryos and larvae for the development of chromatophores and eyespots, and as a vitamin A precursor (Dall, 1995).

Wyban et al. (1997) noted a decrease in nauplius quality with successive spawns associated with a loss of pigmentation in the ovary of L. vannamei. Addition of paprika, an inexpensive source of carotenoids, to the fresh diet at a rate of 2% (2 g paprika per 100 g squid meat), resulted in a significant improvement in nauplius quality (measured as survival to zoea 2 stage).

Pangantihon-Kühlmann and Hunter (1999) found that astaxanthin supplementation (50 mg/kg) of the diet resulted in increased egg production in Penaeusmonodon but could not demonstrate any benefit of astaxanthin supplementation on either hatching rate or metamorphosis to zoea 1 stage.


MISCELLANEOUS FACTORS

Hormones

It has been suggested that some of the more successful live feed organisms may provide benefits through the provision of hormones or their precursors. Naessens et al. (1997) speculated that part of the reason for the success of reproductive adult Artemia biomass supplementation of the diet of L. vannamei broodstock could be due to the presence of specific hormones or analogous peptides in the Artemia that provoked a response in the shrimp. Bloodworms used in maturation have also been found to contain methyl farnesoate, an ecdysone hormone that has been shown to increase reproductive performance in the spider crab Libinia emarginata (Laufer et al., 1987), L. vannamei (Laufer et al., 1997), P. monodon (Hall et al., 1999) and the crayfish Procambarus clarkii (Laufer et al., 1998). In P. clarkii, the hemolymph titer increased from basal levels during early vitellogenesis, peaked during mid-cycle and then returned to basal levels when the ovaries were in late vitellogenesis.


Nucleotides

Nucleotides, the basic building blocks of nucleic acids, are recognised as important elements in mammalian nutrition especially during periods of rapid growth or physiological stress (Uauy, 1989; 1994; Barness 1994; Van Buren, 1994) and also appear to play a key role in the immune system. Traditionally, nucleotides have not been considered essential nutrients although de novo synthesis and salvage pathways are thought to be costly processes in metabolic terms. Several studies have demonstrated that dietary sources of nucleotides can have beneficial effects and the term‘conditionally essential’ has been used to describe their role in nutrition (Carver and Walker, 1995).

Exogenous sources of nucleotides are thought to optimise the functions of rapidly dividing tissues, such as those of the developing embryo and young, and the reproductive and immune systems.

Most aquaculture diet ingredients of animal and plant origin contain nucleotides although there are differences in the concentration and availability. Nucleotide content is particularly high in ingredients such as fish solubles, animal protein solubles, fishmeal, legumes (adenine is particularly high in blackeyed peas), yeast extracts and unicellular organisms such as yeasts and bacteria that are rich in RNA or DNA (Carver and Walker, 1995; Devresse, 2000).

Devresse (2000) noted that the low digestibility of whole yeast compared to yeast extract may be related to the protein (nitrogen) solubility as yeast extract has much higher protein solubility than whole yeast. He also noted that, although fish solubles are highly digestible, they leach easily in water affecting availability.

Reproduction and egg development have a high requirement for RNA and DNA and it may be expected that increasing the availability of nucleotides in broodstock diets may have a beneficial effect on egg development. Recently, research has demonstrated the effect of a nucleotide-enriched diet for broodstock nutrition in aquaculture (Gonzalez-Vecino, 2002; Gonzalez-Vecino et al., 2003).

Nucleotide enrichment of broodstock diets for Atlantic halibut (Hippoglossus hippoglossus) and haddock (Melanogrammus aeglefinus) resulted in a general trend towards better spawning performance and egg quality with the nucleotide diet. Total egg yield was 30% higher in the halibut fed with the nucleotide diet and the relative fecundity, mean egg density, hatching rate and survival of yolk-sac larvae were also significantly improved. Haddock fed on the nucleotide-enriched diet also had significantly higher fertilization and hatching rates. To date, no work has been published on nucleotide supplementation of broodstock diets for shrimp but it would be interesting to conduct some trials to determine if broodstock diets enriched with nucleotides might offer similar benefits in shrimp maturation and breeding. Similarly, the potential for nucleotide supplementation of diets for shrimp larvae should also be investigated.


Larval feeds


Typically, marine larvae are fed with live feeds such as algae, zooplankton, rotifers and Artemia. In some cases, especially with rotifers and Artemia, the fatty acid profile is inadequate (Léger et al., 1986), especially with regard to the HUFA profile. The practice of enrichment has been developed as a means of overcoming this nutritional deficiency.

Enrichment usually involves enhancing the docosahexanoic acid (DHA) and EPA content of the natural feed through ‘bioencapsulation’. This involves feeding the live organism with a DHA/EPA enriched formulation to boost the levels in the tissues and then feeding the enriched organism to the larvae.

In the case of shrimp larvae, the use of enriched Artemia is restricted to the post-larval stages due to the size of the first feeding instar stages of the Artemia (Sorgeloos et al. 1998).


FORMULATED FEEDS

Although live feeds provide an excellent source of nutrition, there are several drawbacks associated with their use. Algal cultures require considerable expertise to maintain them in peak nutritional condition and facilities for their mass production can be expensive to operate. Rotifers also require considerable expenditure in time and effort to maintain, especially if they, in turn, need to be provided with live feed.

Live Artemia nauplii suffer from inconsistent supply and quality as they are obtained from cysts collected in the wild environment. The bulk of cysts come from the Great Salt Lake in Utah in the US where annual fluctuations have been shown to cause wide fluctuations in yield. As a result, price and quality can vary unpredictably (D’Abramo, 2002).

Such problems with live feeds have led to the development of diets specifically formulated for their replacement. However, the development of formulated larval diets to completely replace live feeds has been an elusive goal, despite considerable effort (Langdon, 2003). The difficulties inherent in providing a complete nutritional package in a sufficiently small particle to be ingested and digested by the small larvae of many marine species are clear.

Loss of nutrients from such diets can be rapid and result in loss of nutritional value and fouling of the culture medium and should be used to determine the effectiveness of microparticulates as nutrient delivery systems.

On the other hand, provision of a sufficiently impermeable coat to prevent leaching may result in poor digestibility and availability of the nutrients to the developing larvae. Microbound and cross-linked protein-walled capsules may be used to deliver lipids and high-molecular weight, water-soluble nutrients such as proteins and carbohydrates whereas lipidbased particulates, including liposomes, could be useful in delivering low-molecular weight, watersoluble nutrients, such as amino acids and water-soluble vitamins.

Although the use of formulated larval feeds as partial replacements for microalgae is common in commercial hatcheries, total replacement of algae has proved to be more difficult. Complete replacement has only been achieved using ocean quality seawater that is partly filtered to retain the natural bacterial community (Ottogali, 1991; 1992) and reports of complete replacement in commercial hatcheries appears restricted to those located in the oceanic waters of the Pacific islands (Chim, 2003). Alabi et al. (1997) also showed that total replacement requires the establishment of a balanced bacterial community from either the filtered seawater or following conditioning by microalgae. As a result Jones et al. (1997; 1998) suggested the inoculation of a single dose of live algae (SDLA) before use of artificial feeds to condition hatchery water when it is taken from coastal water of variable bacterial quality.

Wouters and Van Horenbeek (in press) summarize the various types of commercial larval feeds available in the market. These include microbound diets, flakes, granulated feeds, microencapsulated feeds, liquid feeds (lipid-walled capsules).


Microbound feeds are bound using a variety of different binders and produced as a small particle, or as a pellet, cake or flake, which is then crumbled to the appropriate size. They are inexpensive to produce but leach rapidly. Crumbles are usually used during postlarval stages.

Flakes are commonly used in Asia and the Americas. Dietary ingredients are added to water to obtain a dense soup. An appropriate binder is added and the resulting suspension is sprayed onto a steamdrum dryer.

Temperatures can exceed 100°C. and significant nutrient loss can occur unless passage times are kept short.

Large flakes can be crushed and passed through an appropriate mesh screen immediately prior to use. They are generally used for the postlarval stages of the shrimp.

Granulated feeds are produced using liquid binder and water sprayed onto the feed mix, resulting in granules with a raspberry-like structure.

Microencapsulated feeds have an outer coat (capsule) that retains the ingredients inside the particle. They can be designed to have a slow release of the material or to totally prevent leaching of watersoluble nutrients.

Some techniques encapsulate using a cross-linked protein-wall that can be digestible yet capable of  withstanding drying.

Liquid feeds are essentially a slurry of particles in a suspension medium. Although expensive, they are claimed to cause less fouling and can be continuously dosed into larviculture tanks using peristaltic pumps.


CONSIDERATIONS IN DEVELOPMENT OF FORMULATED LARVAL FEEDS

The nutrition of marine larvae involves an understanding of the behavioural, mechanical and physiological processes of feeding in the target animal.

These are likely to be very different in the larval stages compared to the adult form. Feeding habits in many species show a distinct change as the larvae develop. In penaeid shrimp, many species change from a primarily herbivorous diet in the zoea stages to a more omnivorous diet in the postlarval stages (Lemos and Phan, 2001). During the postlarval and early juvenile stages, further changes may involve a switch to a more carnivorous or detritivorous diet depending on the species. There are also changes from a planktonic existence to a benthic one and from a filter feeder to an active predator to be considered, all within a few days of hatching.

One of the key considerations is the development of the gut structure and function. Larval crustaceans have a simple gut structure, which gradually becomes more complex. The physiology of the gut and gut enzymes also changes and, since transit times may be quite short (Jones et al., 1997; Jones and Kurmaly, 1987), designing a nutritious, easily digestible diet is a challenge.


Digestive physiology of marine larvae

The development of the digestive system of marine larvae plays a fundamental role in larval nutrition. In particular the development of gut function and ontogenetic changes in enzyme function are of critical importance.

The structure of the larval gut in crustaceans has been studied in only a few species (Factor, 1981; Lovett and Felder, 1989; 1990a; 1990b; Abubakr and Jones, 1992). The development of gut structure appears to follow similar patterns in most of the species studied. The gut of early larval stages of penaeids is relatively simple and the gastric mill and hepatopancreas are either not present or not yet functional. Feed is mixed with enzymes through expansion and contraction of the midgut gland and there is free fluxing of food between the midgut gland and the midgut, especially in time of food scarcity (Lovett and Felder, 1990b). As the larva grows, the hepatopancreas proper develops, the lobes increasing in number and elongating during the mysis stages.

At this point, the rudimentary gastric filter begins to develop. The postlarval stages are marked by the rapid development of the hepatopancreas, which increases in size and complexity, and the development of the gastric mill and gastric filter to the adult form.

Until the gastric mill becomes functional, the shrimp larvae are restricted to feed items that are relatively easily digestible. In the case of the herbivorous stages, they generally filter the feed from the water and digestion takes place in the gut. As the appendages and mouthparts become stronger and more complex, larger feed particles and live prey are held and torn apart before ingestion, rendering them more easily digestible.

There has been relatively little research into the digestive enzymes of crustacean larvae. Jones et al. (1997) noted that larval enzymes differ in range and level of activity from those that are present in adults and that there exist species differences which may relate to the feeding strategy of the larvae. There are also changes in enzyme activity patterns between different larval stages and, overlaid on these, the possibility of diet-induced changes in enzyme levels.

In a brief review of research into enzyme activity of decapod larvae, Jones et al. (1997) reported that all appeared to have strong protease activity, predominantly trypsin, non-specific esterase activity and amylase. In the few reports available, pepsin appears to be absent in larval and most adult decapods (Glass et al., 1989) although it has been reported in the freshwater prawn, Macrobrachium rosenbergii (Lee et al., 1980). Similarly, lipase activity was only reported in larval stages of the black tiger prawn, Penaeus monodon and the lobster, Homarus americanus although this may be open to debate.

Collagenase, elastase and chymotrypsin all seem to be rare or absent in larval stages.

Changes in enzyme activity patterns with larval stage have been clearly demonstrated in penaeids (Lovett and Felder, 1990a, b; Glass et al., 1989; MacDonald et al., 1989; Ribeiro and Jones, 2000; Ngamphongsai, 2000; Puello-Cruz et al., 2002). MacDonald et al. (1989) noted that the general pattern of amylase, protease and lipase in P. monodon larvae was similar with a maximum of enzymatic activity at zoea 3, possibly coinciding with the change from predominantly filter feeding to mechanical digestion.

They also noted a minimum level of all three enzymes in the early postlarval stage, similar to that noted by Lovett and Felder (1990a) (the so-called ‘enzyme crisis’), which was attributed to a change in gut development associated with changing feeding habits as the postlarvae become more benthic. This coincides with a critical period in postlarval development whenpoor postlarval condition and high mortality may be observed in commercial hatcheries. Puello-Cruz et al. (2002), on the other hand, found that trypsin levels in Litopenaeus vannamei larvae were significantly highest at the Zoea 1 stage, and declined thereafter to the PL1 stage. They also noted that trypsin content in zoea 2 and zoea 3 stage larvae feeding on Artemia was significantly lower than in those feeding on algae and suggested that L. vannamei may be physiologically adapted to transfer to a more carnivorous diet during the zoeal stages than more herbivorous species such as P. monodon or P. indicus (Ngamphongsai, 2000). This accords well with commercial hatchery observations that L. vannamei is capable of feeding on Artemia from the zoea 3 stage whereas P. monodon larvae do not become fully capable of feeding on live Artemia until at least mysis 2 or 3. Changes in the sequence of enzyme activity consistent with a carnivorous diet were also noted in early larval stages of Macrobrachium rosenbergii (Kamarudin et al., 1994).

Several authors have suggested that fish larvae may benefit from the assistance of exogenous digestive
enzymes of their live food organisms, either through autolysis or by the action of zymogens that activate larval endogenous digestive enzymes (Kolkovski et al., 1993; 1997; Munilla-Moran et al., 1990) and the same may hold for crustacean larvae.


LIPIDS

Much work on larval feeds has centred on the lipid requirement, in particular the requirement for highly unsaturated fatty acids (HUFA) and phospholipids.

The n-3 highly unsaturated fatty acids (HUFA) docosahexaenoic acid (22:6n-3, DHA) and eicosapentaenoic acid (20:5n-3, EPA) are essential for normal growth and development of many species of marine fish and crustaceans (Sargent et al., 1999; Jones et al., 1997; Suprayudia et al., 2004). Marine fish are also unable to synthesize arachidonic acid (20:4n-6; AA).

Quantitative requirements for essential fatty acids have been rarely reported for larvae of penaeid shrimp. It has been suggested (Kanazawa et al., 1979, in González-Félix and Pérez-Velazquez, 2002) that 1% n-3 HUFA in the diet could be considered as a minimal value for postlarvae although Chen and Tsai (1986) indicated a requirement for HUFA at 0.5-1% of the diet for P. monodon and Xu et al. (1994) suggested a requirement of between 0.7% and 1% of the diet in Fenneropenaeus chinensis.

The dietary effects of phospholipids on fish and crustacean larvae have been reviewed by Coutteau et al. (1997). Although there appears to be little doubt that crustacean larvae can synthesise phospholipid from HUFA, the addition of dietary sources of phospholipid has been shown to be beneficial, possibly through enhancing the absorption of dietary cholesterol and triacylglycerols (Jones et al., 1997).

Gonzalez-Felix et al. (2000), for example, demonstrated that L. vannamei postlarvae fed diets containing phospholipid demonstrated improved growth and enhanced muscle phosphatidylcholine and phosphatidylethanolamine concentration. Coutteau et al. (1996) however, showed that the other phospholipids in lecithin could not compensate for phosphatidylcholine deficiency in the diet of postlarval L. vannamei and that, as dietary phosphatidylcholine increased, significantly higher levels of total HUFA, 20:1n-9 and 20:5n-3 were present in the shrimp.

In experiments carried out with larval P. japonicus, optimal metamorphosis was obtained with diets containing 15-30 g/kg soybean phosphatidylcholine and the lower level (15 g/kg) was more beneficial to postlarvae (Camara et al., 1997). Results also suggested that there was no requirement for phosphatidylethanolamine or phosphatidylinositol in the presence of adequate dietary phosphatidylcholine. The phospholipid requirement of crustacean larvae from this study appears to be within the range of 1-3% given by Coutteau et al. (1997) as the range for most marine larval species and agrees with the earlier figure of 3% given by Kanazawa (1990).

As with adult crustaceans, larvae are unable to synthesise cholesterol and have an absolute requirement for cholesterol in the diet (Teshima et al., 1983).


PROTEIN AND AMINO ACIDS

The optimal dietary protein level in a larval diet can be expected to vary with species, larval stage (Durruty et al., 2002), protein source, digestibility (Le Vay et al., 1993) and amino acid composition. Kanazawa (1990) recommended protein levels in larval feeds between 23% and 57%. Durruty et al. (2002) reported differences in protein requirement according to the larval stage of L. vannamei and L. setiferus. They estimated that protein requirement increased from 30% in the zoea stages up to 50% or 60% for mysis stages. Data on optimal protein:energy ratiosor amino acid profiles for larval shrimp feeds have not been reported (Wouters and Van Horenbeek, in press).

The essential amino acids for shrimp are thought to be methionine, arginine, threonine, tryptophan, histidine, isoleucine, leucine, lysine, valine and phenylalanine (Akiyama, 1992). There is no reason to believe that shrimp larvae have any specific amino acid requirement that differs from the adult shrimp (Jones et al., 1997). Although no single protein source appears to satisfy the complete requirements for amino acids (Wouters and Van Horenbeek, in press), Cahu (1999) stated that lower nutritional value protein sources can be fortified by the addition of essential amino acids (Cahu, 1999).


CARBOHYDRATES

As with adult crustaceans, there appears to be no specific requirement for carbohydrates in the diet. Carbohydrates can be used to reduce feed costs through protein or lipid sparing and are frequently used as binders in larval feeds.


VITAMINS AND MINERALS

Fat-soluble and water-soluble vitamins as well as carotenoids are essential for shrimp larvae (Wouters and Van Horenbeek, in press). Kanazawa (1986; 1990) determined the vitamin requirements for P. japonicus (Table 1). These levels provide a practical baseline, but Kanazawa (1990) also admits that they may be affected by leaching of the vitamins from the test diet. In practice, formulated feeds for shrimp larvae will contain a complete vitamin and mineral premix as used in feeds for older shrimp.





Kanazawa’s work on vitamin C requirements was conducted using sodium ascorbate. More recently, vitamin C has been available in the form of Lascorbyl-2-polyphosphate. Although there is little work on larval nutrition using this form of the vitamin, work on the early postlarval stages of L. vannamei has shown that high dietary levels (40 mg/kg)can increase resistance to salinity stress. The benefit of elevated dietary vitamin C levels in
increasing stress and disease resistance has also been noted by other authors (Kontara et al., 1997; Merchie et al., 1997; 1998).


OTHERS

Nucleotides have demonstrated much potential when fed to the young or juvenile stages of vertebrates (Carver and Walker, 1995). The benefits of adding dietary nucleotides to feeds for the rapidly developing larval stages of crustaceans would appear to be clear. However, there are no research data available on the application of exogenous nucleotides for crustacean larval culture.

Hatchery operators often use a mixture of additives in a typical feeding regime including additives such as immune stimulants or probiotic bacteria. There is still little or no scientific data to support the use of such additives in shrimp larval culture.


Conclusion


The current state of knowledge of broodstock and larval nutrition of crustaceans contains many gaps. This is partly the result of the complexity and expense of conducting research into these two areas. However, given the increasing importance of domestication in shrimp aquaculture particularly, there is a need for an increased focus on these areas. The role of nutrition in broodstock and maturation performance and in increasing larval survival and quality will be fundamental to obtaining optimal performance from domesticated stocks. Even in species where domestication is not an issue, the improvement of maturation performance and larval production remains a key goal in improving the efficiency of production systems.

It is not clear how far the goal of complete replacement of live feeds may be. It is likely that this will be attained in broodstock diets long before larval feeds. Indeed, given the complexities inherent in supplying a complete nutritional package in a small particle, it may be that this goal is never reached.

However, it may be possible to supply a range of diet particles (e.g. high lipid particles, high protein particles, carbohydrate particles etc.) that are aimed specifically at providing the right mix of nutritional elements in the culture tank that will expose the larvae to the appropriate nutritional mix. Alternatively, it may be that, as expressed by D’Abramo (2002), the complexity of the ontogeny of larval nutritional physiology may mean that technical success will be based on a compromise between the desire to provide a complete diet package and the need to strive for simplicity in formulation and manufacture.


Acknowledgements

I would like to acknowledge the debt owed to Roeland Wouters of INVE Technologies, Belgium and Prof. Patrick Sorgeloos of the University of Ghent for their kind help and provision of access to their publications for use in writing the paper.


References

Abubakr, M.A. and D.A. Jones. 1992. Functional morphology and ultrastructure of the anterior midgut diverticulae of larvae of Penaeus monodon Fabricius, 1798 (Decapoda, Natantia). Crustaceana 62:142-158.


Akiyama, D.M. 1992. Future considerations for shrimp nutrition and the aquaculture feed industry. In: Proceedings of the Special Session on Shrimp Farming (J. Wyban, ed). World Aquac. Soc., Baton Rouge, Louisiana, USA, pp. 198-205.


Alabi A.O., E. Yudiati, D.A. Jones and J.W. Latchford. 1997. Bacterial levels in penaeid larval cultures. In: Diseases in Asian Aquaculture III (T.W. and I.H. MacRae, eds). Fish Health Section, Asian Fisheries Society, Manila, pp. 381-388.

Alava, V.R., A. Kanazawa, S. Teshima and S. Koshio. 1993. Effect of dietary phospholipids and n-3 highly unsaturated fatty acids on ovarian development of Kuruma prawn. Bull. Jap. Soc. Sci. Fish. 59:345-351.


Animulkar, G. 1980. Reproductive physiology of female crustaceans. Ph.D. thesis, Calicut Univ., India.


Barness, L.A.. 1994. Dietary sources of nucleotides - from breast milk to weaning. J. Nutr. 124 (Suppl. 1S):128S-130S.


Cahu, C. 1999. Nutrition and feeding of penaeid shrimp larvae. In: Nutrition and feeding of fish and crustaceans. (J. Guillaume, S. Kaushik, P. Bergot and R. Métailler, eds). Springer, London, UK, pp. 253-263.


Cahu, C., M. Fakhfakh and P. Quazuguel. 1991. Effect of dietary α-tocopherol level on reproduction of Penaeus indicus. In: LARVI ’91— Fish and Crustacean Larviculture Symposium (P. Lavens, P. Sorgeloos, E. Jaspers and F. Ollevier, eds). Ghent, Belgium, Europ. Aquac. Soc. Spec. Pub. No. 15:242-244.


Cahu, C.L., J.C. Guillaume, G. Stephan and L. Chim. 1994. Influence of phospholipid and highly unsaturated fatty acids on spawning rate and egg tissue composition in Penaeus vannamei fed semipurified diets. Aquaculture 126:159-170.


Cahu, C.L., G. Cuzan and P. Quazuguel. 1995. Effect of highly unsaturated fatty acids, alpha-tocopherol and ascorbic acid in broodstock diet on egg composition and development of Penaeus indicus. Comp. Biochem. Physiol. 112:417-424.


Camara, M.R., P. Coutteau and P. Sorgeloos. 1997. Dietary phosphatidylcholine requirements in larval and postlarval Penaeus japonicus Bate. Aquac. Nutr. 3:39-47.


Carver, J.D. and W.A. Walker. 1995. The role of nucleotides in human nutrition. Nutr. Biochem. 6:58-72.


Castille, F. and A.L. Lawrence. 1989. The relationship between maturation and biochemical composition of the gonads and digestive glands of the shrimp Penaeus aztecus Ives and Penaeus setiferus (L.) J. Crust. Biol. 9:202-211.


Chamberlain, G.W. 1988. Stepwise investigation of environmental and nutritional requirements for reproduction of penaeid shrimp. Ph.D. dissertation, Dept. Wildlife and Fisheries Sciences, Texas A&M University, College Station, Texas, USA.


Chim, L. 2003. Crevetticulture en Nouvelle Calédonie. In: Actes de conference - Crevetticulture responsable (B. Coûteaux, Z. Kasprzyk and E. Ranaivoson, eds). Centre d’Information Technique et Economique, Anantanarivo, Madagascar, pp. 128-132.


Coutteau, P., M.R. Camara and P. Sorgeloos. 1996. The effect of different levels and sources of dietary
phosphatidylcholine on the growth, survival, stress resistance and fatty acid composition of postlarval Penaeus vannamei. Aquaculture 147:261-273.


Coutteau, P., I. Guerden, M.R. Camara, P. Bergot and P. Sorgeloos. 1997. Review of the dietary effects of phospholipids in fish and crustacean larviculture. Aquaculture 155:149-164.


D’Abramo, L. 2002. Challenges in developing successful formulated feed for culture of larval fish and crustaceans. In: Avances en Nutricíon Acuícola VI. Memorias del VI Simposio Internacional de Nutricíon Acuícola (L.E. Cruz-Suárez, D. Ricque- Marie, M. Tapia-Salazar, M. Gaxiola-Cortés and N. Simoes, eds). Cancún, Quintana Roo, México.


Dall, W., D.M. Smith, and L.E. Moore. 1995. Carotenoids in the tiger prawn Penaeus esculentus during ovarian maturation. Mar. Biol. 123:435–441.


Deshimaru, O. 1982. Protein and amino acid nutrition of the prawn, Penaeus japonicus. In: Proceedings of the 2nd International Conference on Aquaculture Nutrition: Biochemical and Physiological Approaches to Shellfish Nutrition (G.D. Pruder, C.J. Langdon and D.E. Conklin, eds). Special Pub. No. 2, World Mariculture Society,
Baton Rouge, Louisiana, USA, pp. 106-122.


Devresse, B. 2000. Nucleotides: a key nutrient for the immune system of shrimp? Feed Mix 8(3):20-22.


Durruty, C., L. Maldonado, G. Gaxiola, T. García and R. Pedroza. 2002. Requerimientos de proteina dietética en larvas de Litopenaeus setiferus y Litopenaeus vannamei. In: Book of Abstracts, VIth International Symposium on Aquatic Nutrition, Cancún, Mexico, p. 104.


Factor, J.R. 1981. Development and metamorphosis of the digestive system of larval lobsters, Homarus americanus (Decapoda, Nephropidae). J. Morphology 1969:225-242.


Glass, H.J., N.L. MacDonald, R.M. Moran and R.J. Stark. 1989. Digestion of protein in different marine species. Comp. Biochem. Physiol. 94B(3):607-611.


Gonzalez-Felix, M.L., A.L. Lawrence, D.M. Gatlin, III and M. Perez-Velazquez. 2000. Growth, survival and fatty acid composition of Litopenaeus vannamei postlarvae fed different kinds of lipid in the presence and absence of phospholipid. In: Book of Abstracts, Aquaculture America 2000, p. 8.


González-Félix, M.L. and M. Perez-Velazquez. 2002. Current status of lipid nutrition of Pacific white shrimp, Litopenaeus vannamei. In: Avances en Nutrición Acuícola VI. Memorias del VI Simposium Internacional de Nutrición Acuícola. (L.E. Cruz-Suárez, D. Ricque-Marie, M. Tapia-Salazar, M.G. Gaxiola-Cortés and N. Simoes, eds). Cancún, Quintana Roo, México.


Gonzalez-Vecino, J.L. 2002. Breakthrough in broodstock nutrition. Seafish Aquaculture: Marine Finfish News. No.1, Summer 2002, p. 4.


Gonzalez-Vecino, J.L., C.J. Cutts, R.S. Batty, C. Mazorra and C. Burrells. 2003. The effects of nucleotide supplementation on broodstock and larval performance in Atlantic halibut, Hippoglossus hippoglossus L. and haddock, Melanogrammus aeglefinus L. In: World Aquaculture 2003 Abstracts. World Aquaculture Society, Baton Rouge, Louisiana, USA, p. 325.


Hall, M.R., R. Mastro and G. Prestwich. 1999. Hormonal modulation of spawner quality in Penaeus monodon. In: Book of Abstracts, World Aquaculture ’99. World Aquaculture Society, Baton Rouge, Louisiana, USA, p. 308.


Harrison, K.E. 1990. The role of nutrition in maturation, reproduction and embryonic development of decapod crustaceans: a review. J. Shellfish Res. 9:1-28


Harrison, K.E. 1997. Broodstock nutrition and maturation diets. In: Advances in World Aquaculture vol. 6: Crustacean Nutrition (L.R. D’Abramo, D.E. Conklin and D. M. Akiyama, eds). World Aquaculture Society, Baton Rouge, Louisiana, USA, pp. 390-408.


Jones, D.A., A.B. Yule and D.L. Holland. 1997. Larval Nutrition. In: Advances in World Aquaculture vol. 6: Crustacean Nutrition (L.R. D’Abramo, D.E. Conklin and D. M. Akiyama, eds). World Aquaculture Society, Baton Rouge, Louisiana, USA, pp. 353-389.


Kamarudin, M.S, D.A. Jones, L. Le Vay and A.Z. Abidin. 1994. Ontogenetic changes in digestive enzyme activity during larval development of Macrobrachium rosenbergii. Aquaculture 123:323-333.


Kanazawa, A. 1990. Microparticulate feeds for penaeid larvae. In: Advances in Tropical Aquaculture, Actes de Colloque 9, Aquacop, Ifremer, Tahiti, pp. 395-404.


Kolkovski, S., A. Tandler, G.W. Kissil and A. Gertler. 1993. The effect of dietary exogenous digestive enzymes on ingestion, assimilation, growth and survival of gilthead seabream, (Sparus aurata, Sparidae, Linnaeus) larvae. Fish. Physiol. Biochem. 12:203-209.


Kolkovski, S., A. Tandler and M.S. Izquierdo. 1997. Effects of live food and dietary digestive enzymes on the efficiency of microdiets for seabass (Dicentrarchus labrax) larvae. Aquaculture 148:313-332.


Kontara, L., G. Merchie, P. Lavens, R. Robles, H. Nelis, A. De Leenheer and P. Sorgeloos. 1997. Improved production of post larval white shrimp through supplementation of L-ascorbyl-2-polyphosphate in the diet. Aquac. Inter. 5:127-136.

Langdon, C. 2003. Microparticle types for delivering nutrients to marine fish larvae. Aquaculture 227:259-275.


Laufer, H., D. Borst, F.C. Baker, C. Carrasco, M. Sinkus, C.C. Reuter, L.W. Tsai and D.S. Schooley. 1987. Identification of a juvenile hormone-like compound in a crustacean. Science 235:202-205.


Laufer, H.J. Paddon and M. Paddon. 1997. A hormone enhancing larva production in the Pacific White Shrimp, Penaeus vannamei. In: IV Symposium on Aquaculture in Central America: Focusing on Shrimp and Tilapia, Asociación Nacional de Acuicultores de Honduras (ANDAH) and the Latin American Chapter of the World
Aquaculture Society, Tegucigalpa, Honduras, pp. 161-162.


Laufer, H., W.J. Biggers and J.S.B. Ahl. 1998. Stimulation of ovarian maturation in the crayfish, Procambarus clarkii by methyl farnesoate. Gen. Comp. Endoc. 111:113-118.


Lee, P.G., N.J. Blake and G.E. Rodrick. 1980. A quantitative analysis of digestive enzymes for the freshwater prawn Macrobrachium rosenbergii. Proc. World Mariculture Society II, pp. 392-402


Léger, P., D.A. Bengtson, K.L. Simpson and P. Sorgeloos. 1986. The use and nutritional value of Artemia as a food source. Oceanography and Marine Biology 24:521-623.


Lemos, D. and V.N. Phan. 2001. Ontogenetic variation in metabolism, biochemical composition and energy content during the early life stages of Farfantepenaeus paulensis (Crustacea: Decapoda: Penaeidae). Marine Biology 138:985-997.


Lovett, D.L. and D.L. Felder. 1989. Ontogeny of gut morphology in the white shrimp Penaeus setiferus (Decapoda, Penaeidae). J. Morphology 201:253-272.


Lovett, D.L. and D.L. Felder. 1990a. Ontogenetic change in digestive enzyme activity of larval and postlarval white shrimp, Penaeus setiferus (Crustacea, Decapoda, Penaeidae). Biological Bulletin 178:144-159.


Lovett, D.L. and D.L. Felder. 1990b. Ontogenetic changes in enzyme and enzyme distribution and midgut function in developmental stages of Penaeus setiferus (Crustacea, Decapoda, Penaeidae). Biological Bulletin 178:160-174.


MacDonald, N.L., R.J. Stark and M. Keith. 1989. Digestion and nutrition in the prawn, Penaeus monodon. J. World Aquac. Soc. 20:53A.


Marsden, G.E., J.J. McGuren and S.W. Hansford. 1997. A moist artificial diet for prawn broodstock: its effect on the variable reproductive performance of wild caught Penaeus monodon. Aquaculture 149:145–156.


Mendez, L., B. Acosta, and I.S. Racotta. 1997. Mineral concentrations of Penaeus vannamei broodstock in a hatchery. In: IV symposium on aquaculture in Central America: focusing on shrimp and tilapia. Tegucigalpa, Honduras, Asociacion Nacional de Acuicultores de Honduras and the Latin American Chapter of the World Aquaculture Society, pp. 163-165.


Merchie, G., P. Lavens and P. Sorgeloos. 1997. Optimisation of dietary vitamin C in fish and crustacean larvae: a review. Aquaculture 155:165-181.


Merchie, G., E. Kontara, P. Lavens, R. Robles, K. Kurmaly and P. Sorgeloos. 1998. Effect of vitamin C and astaxanthin on stress and disease resistance of postlarval tiger shrimp, Penaeus monodon Fabricius. Aquacult. Res. 29:579-585.


Munilla-Moran, R., J.R. Stark and A. Barbour. 1990. The role of exogenous enzymes on the digestion of cultured turbot larvae, Scopthalmus maximus L. Aquaculture 88:337-350.


Naessens, E., P. Lavens, L. Gómez, C. Browdy, K. McGovern-Hopkins, A. Spencer, D. Kawahigashi and P. Sorgeloos. 1997. Maturation performance of Penaeus vannamei co-fed Artemia biomass preparations. Aquaculture 155:87-101.


Ngamphongsai, C. 2000. Tryptic enzyme content in the larval stages of Elminius modestus Darwin, Crangon crangon Linnaeus and Penaeus indicus H. Milne Edwards. In: Proc. 2nd National Symposium on Marine Shrimp. National Center for Genetic Engineering and Biotechnology. Bangkok, Thailand, pp 169-175.


Ottogali, L. 1991. Total substitution of microparticles for algae for Penaeus stylirostris larval rearing in New Caledonia. J. World Aquac. Soc. 22:46A.


Ottogali, L. 1992. Nueva gestion del agua en las crias de peneidos en Nueva Caledonia Mem. In: 1er Congreso Ecuatoriano de Acuicultura (J. Calderon and V. Sandoval, eds). CENAIM, Guayaquil, Ecuador, pp. 87-91.


Palacios, E., A.M. Ibarra, J.L. Ramirez, G. Portillo and I.S. Racotta. 1998. Biochemical composition of eggs and nauplii in Pacific White Shrimp, Penaeus vannamei Boone, in relation to the physiological condition of spawners in a commercial hatchery. Aquacult. Res. 29:183-189.


Palacios, E., C.I. Perez-Rostro, J.L. Ramirez, A.M. Ibarra and I.S. Racotta. 1999. Reproductive exhaustion in shrimp Penaeus vannamei reflected in larval biochemical composition, survival and growth. Aquaculture 171:309-321.


Palacios, E., A.M. Ibarra and I.S. Racotta. 2000. Tissue biochemical composition in relation to multiple spawning in wild and pond-reared Penaeus vannamei broodstock. Aquaculture 185:353-371.


Pangantihon-Kühlmann, M and W.B. Hunter. 1999. Astaxanthin supplementation levels on the reproductive performance of pond-sourced Penaeus monodon broodstock. Presented at: The 5th Roche Aquaculture Conference. Bangkok, Thailand.


Puello-Cruz, A.C., R.S. Sangha, D.A. Jones and L. Le Vay. 2002. Trypsin enzyme activity during larval development of Litopenaeus vannamei (Boone) fed on live feeds. Aquaculture Research 33:333-338.


Ravid, T., A. Tietz, M. Khayat, E. Boehm, R. Michelis and E. Lubzens. 1999. Lipid accumulation in the ovaries of a marine shrimp Penaeus semisulcatus De Haan. J. Exp. Biol. 202:1819-1829.


Read, G.H.L. and M.S. Caulton. 1980. Changes in mass and chemical composition during the molt cycle and ovarian development in immature and mature Penaeus indicus Milne Edwards. Comp. Biochem. Physiol. 66A:431-437.


Ribeiro, F.A.L.T. and D.A. Jones. 2000. Growth and ontogenetic change in activities of digestive enzymes in Fenneropenaeus indicus postlarvae. Aquac. Nutr. 6:53-64.


Sargent, J.R., L.A. McEvoy, A. Estevez, J.G. Bell, M.V. Bell, R.J. Hendersron and D.R. Tocher. 1999. Lipid nutrition of marine fish during early development: current status and future directions. Aquaculture 179:217-229.


Sorgeloos, P., P. Coutteau, P. Dhert, G. Merchie and P. Lavens. 1998. Use of the brine shrimp Artemia sp. in larval crustacean nutrition: a review. Rev. Fisheries Sci. 6(1&2):55-68.


Suprayudia, M.A., T. Takeuchia and K. Hamasakib. 2004. Essential fatty acids for larval mud crab Scylla serrata: implications of lack of the ability to bioconvert C18 unsaturated fatty acids to highly unsaturated fatty acids. Aquaculture 231:403-416.


Teshima, S., A. Kanazawa and H. Sasada. 1983. Nutritional value of dietary cholesterol and other sterols to larvae of the prawn, Penaeus japonicus Bate. Aquaculture 31:159-167.


Teshima, S., A. Kanazawa, S. Horinouchi and S. Koshio. 1988. Lipid metabolism in destalked prawn Penaeus japonicus: induced maturation and transfer of lipid reserves to the ovaries. Bull. Jap. Soc. Sci. Fish. 54:1123-1129.


Uauy, R. 1989. Dietary nucleotides and requirements in early life. Pp. 265-280 in Lebenthal, E (ed.) Textbook of Gastroenterology and Nutrition in Infancy. 2nd Edn. Raven Press, New York, USA.


Uauy, R 1994. Non-immune system responses to dietary nucleotides. J. Nutr. 124(Suppl. 1S):157S-159S.


Van Buren, C.T., A. Kulkarni and F.B. Rudolph. 1994. The role of nucleotides in adult nutrition. J. Nutr. 124(Suppl 1S):160S-164S.


Wouters, R. and T. Van Horenbeeck. In Press. Larval Shrimp Feeds: Current status. In: Responsible Aquaculture for a Secure Future: Proceedings of a Special Session on Shrimp Farming, World Aquaculture 2003. (D.E. Jory, ed). The World Aquaculture Society, Baton Rouge, Louisiana, United States. pp. 90-109.


Wouters, R., L. Gomez, P. Lavens and J. Calderon. 1999a. Feeding enriched Artemia biomassa to Penaeus vannamei broodstock: its effect on reproductive performance and larval quality. J. Shellfish Res. 18:651-656.


Wouters, R., C. Molina, P. Lavens, and J. Calderon. 1999b. Contenido de lipidos y vitaminas en reproductores silvestres durante la maduracion ovarica y en nauplios de Penaeus vannamei. Proceedings of the Fifth Ecuadorian Aquaculture Conference, Guayaquil, Ecuador, Fundacion CENAIM-ESPOL, CDRom.


Wouters, R., P. Lavens, J. Nieto and P. Sorgeloos. 2001a. Penaeid shrimp broodstock nutrition: an updated review on research and development. Aquaculture 202:1-21.


Wouters, R.X. Piguave, L. Bastidas, J. Calderón and P. Sorgeloos. 2001b. Ovarian maturation and haemolymphatic vitellogenin concentration of Pacific white shrimp Litopenaeus vannamei(Boone) fed increasing levels of total dietary lipids and HUFA. Aquac. Res. 32:573-582.


Wyban, J. G. Martinez and J. Sweeney. 1997. Adding paprika to Penaeus vannamei maturation diet improves nauplii quality. World Aquac. 28(2):59-62.


Xu, X.L., W.J. Ji, J.D. Castell and R.K. O’Dor. 1992. Influence of dietary lipid sources on fecundity, egg hatchability and fatty acid composition of Chinese prawn (Penaeus chinensis) broodstock. Aquaculture 119:359-370.


Xu, X.L., W.J. Ji, J.D. Castell and R.K. O’Dor. 1994. Effect of dietary lipid sources on fecundity, egg hatchability and egg fatty acid composition of Chinese prawn (Penaeus chinensis) broodstock. Mar. Fish. Res. 13:13-19.

(4405)
(7)
Mohammad
down arrow
Bandar Abbas , Hormozgan, Iran
Agriculturist
Re: Forum: Feeds for the future: the importance of better broodstock and larval nutrition in successful aquaculture
12/27/2012 |

Dear sir/ madam
What's your idea if we use the sand worm ( red California worm) In maturation diet how's the profile of this worm if we replaced whit blood worm because this worm is more cheap than blood worm 
Best regard
M.gorgij

(0)
(0)
Melissa Rommens
down arrow
Montague, Prince Edward Island, Canada
Consultant
Re: Forum: Feeds for the future: the importance of better broodstock and larval nutrition in successful aquaculture
02/12/2013 |

I am seeking a vitamin supplement for cold water marine fish that is encapsulated or otherwise bound in a pellet (e.g. wheat middlings). The intent is to insert the vitamins into raw fish for feeding to recently caught wild broodstock. Does anyone know of a source for such a supplement, or a company that can make a supplement to my specifications - without requiring an excessively large order?

(1)
(0)
Chris Bentley
down arrow
Quinby, Virginia, United States
Recirculating Aquaculture Farm Manager
Re: Forum: Feeds for the future: the importance of better broodstock and larval nutrition in successful aquaculture
02/13/2013 |

We used to break up children's chew-able vitamins and put the pieces inside the raw fish. Low tech approach but effective. You can even get them with extra DHA now.

(0)
(0)
Melissa Rommens
down arrow
Montague, Prince Edward Island, Canada
Consultant
Re: Forum: Feeds for the future: the importance of better broodstock and larval nutrition in successful aquaculture
02/13/2013 |

The problem with this is an imbalance of key Vitamins. Overdose of some, underdose of others.

(0)
(0)
Chris Bentley
down arrow
Quinby, Virginia, United States
Recirculating Aquaculture Farm Manager
Re: Forum: Feeds for the future: the importance of better broodstock and larval nutrition in successful aquaculture
02/21/2013 |

You could try Invie breed-M. I have used that and mixed with gelatin to improve water stability. It is intended to be used as a fully balanced semi-moist diet. So it is not going to be like a vitamin/mineral pre-mix, but could probably be inserted into raw fish and give them a boost that is formulated for broodstock. If you can get the fish onto the semi-moist diet, that product is well formulated.

(0)
(0)
Melissa Rommens
down arrow
Montague, Prince Edward Island, Canada
Consultant
Re: Forum: Feeds for the future: the importance of better broodstock and larval nutrition in successful aquaculture
02/21/2013 |

Thanks Chris. We've talked about Breed M and there's a trial underway now to see how some marine fish perform reproductively so we are looking forward to those results.
We currently insert a dry broodstock feed formulated for salmonids into the wet fish.
We previously had tried converting our brood to a commercially produced broodstock feed that we made into a moist pellet and the results were near disastrous: poor acceptability, poor body condition, poor spawning results. We are therefore a little cautious now about this prospect.

(0)
(0)
Re: Forum: Feeds for the future: the importance of better broodstock and larval nutrition in successful aquaculture
06/10/2013 | I am Adedeji Olushola Isaiah by name. i attended a seminar at Abuja where by the person said there is nothing like broodstock that the fish were just table size.
(0)
(0)
Would you like to discuss about this topic: Feeds for the future: the importance of better broodstock and larval nutrition in successful aquaculture?
Engormix reserves the right to delete and/or modify comments. See more details

Comments that contain the following items won´t be published:

  • Repeated spelling mistakes.
  • Advertisements, Web sites and/or e-mail addresses.
  • Questions or answers not relevant to the topic discussed in the Forum.
POST A COMMENT
ABSTRACT A field study was conducted on brood stock Nile tilapia to increase...
 
In the present work, feeding O. niloticus fish on diets containing different le...
a - Melike Gür - In Turkey we cant produce Artemia as rotifers... Is it possible...
 
a - Mohammad Hosseini - This is a lot of help to fish in the Indian Ocean. ...
Professional Services
Gary J. Burtle Gary J. Burtle
Tifton, Georgia, United States
Philippe Douillet Philippe Douillet
Miami, Florida, United States
    |     Who are we?     |     Advertise on Engormix
Copyright © 1999-2014 Engormix.com - All Rights Reserved