shrimp maturation diets
From: Leland lelandlei@aquafauna.com
To: shrimp@yahoogroups.com
Date: 17 July 2003
comments 1:
(…) The more interesting findings were that the
HUFA levels in Maine bloodworms tended to differ from season to season and
we concluded that this was a function of intake diet. The proximate
analysis of proteins, carbohydrates, etc. remain relatively stable with some
minor changes from season to season. However, the HUFA's did change
and increased or decreased depending on whether it was winter (low algal
periods) versus summer.
The issue boils down to "flesh" or "content" value
and we concluded that the value of polychaetes was more in the
contents rather than in the flesh. Bloodworms were a good carrier of
the contents which tend to have very positive effects on the maturation and
spawning process.
We further looked at the effects of bloodworms available from more
tropical climates but these do not tend to produce the same results.
Profile them and you find typically that tropical organisms tend to be of a
different HUFA profile and have (generally) lower levels of the 20 and 22
series fatty acids.
We further compared calamari caught locally in more tropical regions for use
in maturation diets and compared them against performances of cold water
source calamari and again, the difference was quite noticeable in the HUFA
levels, especially in the DHA (for both bloodworms and for calamari).
Diets are often a function of perception and what we think would be best is
what the practitioner ends up using. In Vietnam, it is common to
catch hermit crabs and keep them alive until use. They then extract the
animals for the broodstock monodon and they are consumed in a live form. The
presentation is good (e.g. can't get any fresher than live), but the
profiles in HUFA was relatively low in EPA and DHA compared to other diets
of colder water origin.
Common fact, look at the lipid profiles of pollack, cod, and other deepwater
fish. Much higher in EPA and DHA. compared to flesh content of more
tropical species like bream, bass and grouper.
More important is the correct ratio between EPA and DHA.
Indications are that the "optimal" ratios for EPA and DHA vary as
a requirement from species to species.
We know from field trials, that we can promote onset of early spawning by
varying the levels of DHA in L. vannamei.
We also see different effects when using other frozen maturation diets that
have substantially different EPA and DHA content. Compare the Mysis
(deep freshwater copepods) with that of krill (Euphasia which is saltwater).
While Mysis is from deep freshwater caught above the 45 degree latitude, it
has 3-4 times the EPA and DHA content as compared to krill caught in the
North Pacific.
Most enriched Artemia is enriched with Menhaden oil, which is a fish of
sub-tropical origin (East Coast US & Gulf of Mexico, etc.). I
would suspect that if the Artemia were enriched with pollack or cod oil,
this would boost the overall EPA/DHA levels of what is now commercially
available.
Leland Lai
Aquafauna Bio-Marine, Inc.
e-mail :
lelandlai@aquafauna.com
***************
comments 2:
I have a set of small ponds where I grow vannamei
broodstock animals from harvest size (variable) to about 40 to 50 g when I
send them to the
maturation. At the farm they are fed only standard dry feed 35% protein.
When they get to the hatchery they spawn after about one or two weeks, with
12% mating average and about 140000 npls/spawn per animal. Do you know
how I could help them mature in the ponds, maybe using fresh feed, squid,
Artemia biomass, oysters? These are the locally available ingredients. How
about making a fresh feed with those ingredients and maybe mixing some dry
feed, obtaining some king of paste with the idea of a better feed
management, storage, eventually the possibility of freezing that paste?
Francois Brenta
e-mail:
fbrenta@hotmail.com
***************
comments 3:
In Venezuela we grow our broodstock likewise in ponds
on the farm. We found that the addition of frozen sardines and squid helped
the animals growth rate and ovarian development of the females markedly.
We were able to bring the animals into the maturation unit and have them
ready to spawn almost immediately without having to wait for them to
develop. We also began to find mature and even mated animals in the ponds.
Chris Denmark
e-mail :
cdenmark@seafarmsgroup.com
***************
comments 4:
We are located in Brazil, squid and sardines
shouldn't be a problem, what quantities are you using? How do you monitor,
with feeding trays? Don't you have problems with water quality with fresh
food?
Francois Brenta
e-mail:
fbrenta@hotmail.com
***************
comments 5:
Fresh feed is used once the animals reach 20g in size
at about 1% of the calculated biomass. Yes we monitor these in feed trays.
We do exchange above 10% of the water daily as particularly with the
sardines it can create water quality problems. The main diet is a
standard 35% protein pond diet with the fresh food really as a
supplement in the last couple of months before the animals are
transferred to Maturation.
Chris Denmark
e-mail :
cdenmark@seafarmsgroup.com
***************
comments 6:
1) Matt pointed a much passed over issue that most of
us overlook in the interest of supplying a good quality diet for
conditioning and maturation....that of disease vectors. In most of the
countries like Brazil, Belize, and Venezuela, where there are isolation
regulations on the import of most crustaceans, whether live or frozen, many
hatcheries have gone to making their own diet, using locally available fresh
ingredients, or importing maturation diets that are either ready to use
(pelleted or extruded) or those that can be made on site into a moist more
palatable form (sent as a dry mix but with special binders included).
The use of locally available live or fresh ingredients are ok only so long
as there are no known reported cases of viruses or pathogens the rest of the
world has contact with.....but there still is a open risk of other unknown
pathogens using the local supplies as a vectors.
generally work better for broodstock conditioning than those caught in
sub-tropical or tropical zones. This is also related to the HUFA
content.
3) Most important, however, is that for any captive breeding program, a pond
does not present the wide spectrum of natural diets available to wild
broodstocks in the ocean. As such, the whole philosophy of culturing
broodstock has to be looked at as a micro-managed area of hatchery and farm
operation. That is, the broodstock has to be treated
as broodstock probably from PL stage onward. Separate care, separate
data keeping, separate ponds, diets, water quality management, etc.
In most of Latin America, the hatcheries are somehow integrated or connected
with the growout either by ownership or by contracts. The hatchery
output product is not just the number of PLs produced...almost anyone can do
that. The operating goals should be based on quality PL's that result
in the best survival and overall health for growout and after transfer to
the farms.
This process does not start during the larval stage
but even before that...from the broodstocks that produce the spawns that
supply the naups. The philosophy is sort of the circle of life and you
cannot just take pond grown animals selected at say 30 grams and decide that
these are now going to be your broodstock group.
In Asia, many mom and pop hatcheries look at the end of their responsibility
once the PL's leave their hatchery. Just because they are kicking does
not mean they are healthy or of quality stock....just test the lipid levels
in those from top quality hatcheries verses those that sell for cheap cheap.
4) Broodstock ponds that accommodate PL-10 on should have a management
program that is all encompassing of not only nutrition but perhaps other
pond designs (depth considerations), water quality considerations (level of
exchange, biosecurity, fauna and flora content,
etc.) that would not normally be part of the husbandry considerations of a
standard growout pond.
After all, the brood stock, whether just for captive breeding or part of a
selective breeding program, is this industry's future livelihood.
Leland Lai
e-mail:
lelandlai@aquafauna.com
***************
comments 7:
A more direct answer to your special treatment
question for animals held in growout ponds:
1) Generally, use a good quality diet from PL10 onward once pond stocked.
Often, this starts out with an acclimation diet that should
be very high in lipids (some out there are as high as 22% lipids. This
is used for the first couple of weeks after transfer from hatchery to
destress the animals and acclimate them to the pond environment.
Technically, this should be done in an acclimation raceway before general
release into the ponds. Once in the ponds, use a locally produced diet
with around 8-10% fat content, and 35% protein if vannamei or 40%+ if
monodon. Monitor your phytoplankton levels.
2) Such designated ponds probably should have stand-by aeration.
3) At around 25-28 grams (vannamei), selected animals should be separated
and move to broodstock tanks which are not of earthen bottoms (tanks).
Technically, this would be a good time to close or semi close the system,
since for most farm operations, closing the pond system is not practical.
4) Once in the broodstock tanks, you can apply the assortment of frozen or
fresh diets to AUGMENT some basic dry or moist diet or those which might be
formulated specifically for conditioning or maturation. These formulated
diets should be used as the vehicle for
stabilizing the HUFA input to your animals. Generally, if you get a
high protein diet (circa 40%) that has a 8-9% fat level, but which has been
over-sprayed with squid or anchovy oil (total content of internal and
overcoat is then anywhere from 10-12%), this would be
ideal for the broodstock tanks. We know many hatcheries which do the
application of the overcoat oils on site.
5) When you want to condition the animals for spawning, it is important that
the DHA levels are increased. This is harder to do using fresh or
natural diets especially if you are of tropical or sub-tropical origin (the
natural or fresh diet source that is). Here, you can seek out a
supplemental diet or one made specially for maturation. The lipid
levels on some of these are approaching (total) +14%, but the DHA
content should be +10% of total fatty acids. This will generally accelerate
the egg production.
We get these levels by adding heterotrophic algaes (that are specifically
cultured for DHA), into our maturation moist diet. You can contact us
offline for more information. Most of the large hatcheries in Brazil
are using this maturation diet.
Leland Lai
Aquafauna Bio-Marine, Inc.
lelandlai@aquafauna.com
***************
comments 8:
Do you only use the frozen sardines when growing the
broodstock to production size, or do you also use the sardines during
maturation/reproduction?
e-mail:
toddblacher1@yahoo.com
***************
Comments 9:
No we only use these for the broodstock, maturation
diets are standard
fare of squid, good quality polychaetes , locally sourced bivalves and
broodstock dry diet.
Chris Denmark
e-mail:
cdenmark@seafarmsgroup.com
***************
comments 10:
My personal apreciation of the many maturation
hatcheries I visit is that things may depend on the potential of the shrimp
and its capacity to ingest feed.
I will agree that quality of feed is important and in this comment I will
assume that the nutritional quality is not a limiting factor (theorical of
course).
Then it is my appreciation that the quantity of feed a shrimp be able to
ingest may drive the quantity of eggs spawned. Feed characteristics such as
palatability, digestibility and water quality will increase or decrease the
quantity of eggs the female may built in the short time she has between two
spawns.
If we remember an ablated female has an uncontrolled and accelerated
maturation process, we can apreciate speed / time is an issue and the
quantity of feed ingested in the 3-4 interim days is important.
Water quality is an issue as many fresh feed spoil the water; in
consequence; this reduce the feeding activity of shrimps... thus reducing
their global intake as well as any other stressing factors.
As a general form live feeds will hold better in water and not spoil it
immediately; but if you have a good frozen feed that is eaten in a matter of
minutes; there is no issue.
I have no experience to compare live bloodworm but I do not believe it makes
a significant difference with undamaged live-frozen polychaetes.
Leland's description of HUFA and I will add lipids variation through the
seasons is correct and well documented. Natural wild polychaetes will vary
very much according to seasons as well as locations within the same species.
Lipids / Hufa are not the only thing that changes in polychaetes with time.
HUFA and total energy is certainly an essential factor for successful
maturation but we believe there are other molecules which may not be
strictly nutritional such as pigment, hormones or precursors present too.
Disease and contaminants as heavy metals in particular are additional risk
of use of wild polychaetes. Just do a quick research on internet with the
word "polychaete" to realize how good they are at
bio-accumulation.
That is the reason why we promote and support farm-raised polychaete for
maturation. A responsible aquaculture form and predictible feed.
Eric Pinon
e-mail:
epinon@euca.net.ec
***************
comments 11:
You mentioned "...the broodstock has to be
treated as broodstock probably from PL stage onward. Separate care,
separate data keeping, separate ponds, diets, water quality management, etc.
"
...how about mass selection? I have the idea that it is important that the
future broodstock should be on the contrary submitted to the same (if not
worst) environmental conditions so that the next generation be more
efficient in that specific environment. We have separated ponds for stocking
shrimp from an average 12g to 40g where they are given a separate treatment
just as you mentioned.
Francois
Brenta
e-mail :
fbrenta@hotmail.com
***************
Comments 12:
Nothing is contrary to your ideas of mass selection.
First, in many captive or selective breeding programs, when there is either
a physical or molecular way of tracking animals stocked in a common pond,
then technically, the pond environment is held constant since all varied
factors are exposed to the entire pond population. As such, you
are minimizing the environmental variables part of the equation as it
affects performance since theoretically, all the animals are exposed to the
same conditions.
2) If, in fact, you have implemented better nutrition or water quality,
etc., this will be expressed technically by better growth, development,
survival, etc. by the pond population as a whole. The differences you
see within the bell curve of the pond population, however, may have more of
a molecular basis since the environmental variances were the same for all
animals.
Hence, selection is more likely to be based on genetic reasons for many
traits of fitness like fast growth, since you will select by length or
weight or some other criteria that are associated with faster growth
relative to the mid or bottom portions of the bell curve for any given trait
performance.
3) Pond stocking can be made with either relatively few spawns or with a
mixture of many spawns depending on your ability to sort these out for later
selection with the use of physical tags or molecular tags.
4) You can cross reference the stockings in which the A group of a batch
goes for intended broodstock treatment and B group of the same
offspring/siblings go to standard growout where the conditions may not be so
optimized as for the A group. You can then test for performance under the
two different sets of environmental variances.
Certainly, if Group B (Standard growout protocol) pond is located near or
adjacent to Group A, but does not perform as well as Group A (but on
par with the other standard growout ponds), then the indications are that
environmental factors are probably being expressed more than the genetic
factors as the cause of the difference between A & B ponds. .
Optimization of the conditions for Group A, however then allows you to make
selections on other than the culturing conditions. (e.g. the genetic), while
insuring more optimal growout conditions for later stages of broodstock
maintenance.
Leland Lai
Aquafauna Bio-Marine, Inc,
Aquatic Stock Improvement Company
e-mail:
lelandlai@aquafauna.com
***************
comments 13:
I have just read the interesting comments on
bloodworms. I would like to quote one of my previous publications on this
topic because it contains parts on "unknow maturation stimulating
compounds" (as mentioned by Eric) and it also provides some second
thoughts on the opinion that the succes of bloodworms is primarily linked to
its fatty acid composition (as mentioned by Leland). My apologies for this
rather long contribution, and for quoting myself.
From Wouters et al. 2001 (R. Wouters, P. Lavens, J. Nieto, P. Sorgeloos,
2001. Penaeid shrimp broodstock nutrition: an updated review on research and
development. Aquaculture 202: 1-21):
Fresh or fresh-frozen marine organisms are used for acceptable
maturation and reproduction outputs. Often, these marine organisms are found
to give the best results when they are in a reproductive stage.
Squid and bivalves (mussel, clam, oyster) are generally the main food
items, fed at high daily ratios. Crustaceans like shrimp, crab and krill
are also fed to shrimp spawners, but due to the risk of disease
transmission, they are used less frequently nowadays. Bloodworms (marine
polychaetes Glycera dibranchiata and Americonuphis reseii) and Artemia
biomass (ongrown Artemia) are used for diet supplementation. Bloodworm is
the most expensive ingredient used in hatcheries of the Western atmosphere,
and maturation operators feel it to be indispensable for stimulation of
ovarian maturation (Kawahigashi, 1998). Artemia biomass (usually boosted
with specific nutrients) has been reported to stimulate ovarian maturation,
increase spawn frequency and improve larval quality (Browdy et al., 1989;
Naessens et al., 1997; Wouters et al., 1999). Artemia biomass can also be
included into artificial broodstock diets as a freeze-dried meal to increase
diet ingestion and stimulate ovarian maturation (Wouters et al., 2000b). As
mentioned earlier, Middleditch et al. (1980) and Lytle et al. (1990)
attributed the success of bloodworm to its HUFA composition. On the
contrary, Luis and Ponte (1993) provide evidence that the bloodworm effect
in M. kerathurus is not related to its HUFA level, and also Naessens et al.
(1997) replaced bloodworm successfully with Artemia biomass, which has a
distinct fatty acid profile. In the study conducted by Cahu et al. (1995), a
controlled dietary treatment of fresh mussel gave the highest fecundity and
hatch rate results, outcompeting artificial diets that had similar n-3 HUFA
levels than mussel. While it is clear that HUFA play a crucial role in
shrimp reproduction, it should be remembered that lipid quality is not
determined by its fatty acid composition only. Care should be taken not to
overlook the contribution of nutrients other then HUFA. For example, the
high nutritional value of squid is also attributed to its amino acid
composition - which is similar to that of shrimp (Shigueno, 1984; Bray et
al., 1990a) – and because it contains high sterol levels.
The observation that nutrient composition cannot always explain the success
of natural food organisms made many researchers believe that
reproductive hormones of these organisms contribute to the shrimp
endocrinological cycle. This could be true in organisms that share the
same hormones as penaeid shrimp. The role of hormonally active
substances has been suggested for Artemia biomass in reproductive stage
(Naessens et al., 1997) and bloodworm (Laufer et al., 1998). Laufer found
that bloodworms contained methyl farnesoate, which is an ecdysone hormone
that increased fecundity and hatch rate in cultured L. vannamei shrimp
(Laufer et al., 1997) and P. monodon (Hall et al., 1999), and enhanced
ovarian development in other crustaceans (Laufer et al., 1998). Conclusive
studies regarding the hormonal contribution of diet are non existent to
date, but a study by Mendoza et al. (1997) provides supportive evidence to
the notion that the so called "squid factor" might be a hormonally
active substance.
Roeland Wouters