In aquaculture, environmental impacts such as deteriorated water quality and poor pond bottoms are becoming challenging and omnipresent problems. This article highlights measures which can be taken to improve the quality of water and soil in aquaculture ponds, and therefore the immediate environment of fish and shrimp. Better rearing conditions will improve the overall performance of your fish and shrimp.

1. July | August 2012
Enzymes to improve water and soil quality in
aquaculture ponds
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The International magazine for the aquaculture feed industry

2. FEATURE
Enzymes to improve
water and soil quality in
aquaculture ponds
by Elisabeth Mayer MSc, BIOMIN, Austria
I
n aquaculture, environmental Some specific enzymes can be active
impacts such as deteriorated in a very wide range of environmental
water quality and poor pond conditions. While some micro-organ-
bottoms are becoming challeng- isms have a narrow range of environ-
ing and omnipresent problems. This mental conditions where they are able
article highlights measures which can Picture 1: Samples of the pond bottom to proliferate (pH, oxygen, availability,
be taken to improve the quality of soil of the AquaStar® groups etc.), certain enzymes are able to act
water and soil in aquaculture ponds, in multiple environments. They remain
and therefore the immediate envi- active even when environmental condi-
ronment of fish and shrimp. Better tions change drastically, especially if
rearing conditions will improve the they are immobilised on a carrier. For
overall performance of your fish and example, protease is able to work
shrimp. effectively in pHs between four and 11
Picture 2: Samples of the pond bottom and with temperatures less than 20 °C
As the aquaculture industry soil of the control groups and greater than 70 °C (Whiteley et
expands and develops, several chal- al., 2002).
lenges have arisen. A key problem caused by When added to the culture water or spread Furthermore, another advantage of this
aquaculture operations is its environmental on top of the pond bottom soil, enzymes are immobilisation is that the enzyme activity is
impact. Intensive aquaculture pond systems able to degrade the major organic constitu- preserved and can thus be reused (Karam and
result in high organic loadings that cause dete- ents normally found in shrimp and fish ponds. Nicell, 1997).
riorated water quality and pond bottom and Each enzyme has its mode of action and is There is currently a lot of interest in
the accumulation of toxic compounds such very specific in the chemical reaction it cataly- manufacturing such enzyme preparations
as ammonia, nitrites and hydrogen sulfides. ses. For example, protease hydrolyzes insolu- despite the high costs of isolation, purification
This changes the bacterial composition in the ble proteins and amylase polysaccharides such and production. Nevertheless, some of these
water and soil of ponds by increasing the pres- as starch; cellulase catalyses the breakdown products are already being used as bioreme-
ence of pathogenic bacteria, thus contributing of cellulose (the major cell wall material in diation agents in aquaculture.
plants); ß-Glucosidase is involved in catalysing
greatly to the occurrence of diseases in fish
and shrimp farming. the hydrolysis and biodegradation of various Proven benefits of bioremediation
ß-glucosides present in plant debris; and lipase Enzymes have the capacity to stabilize the
Direct enzyme application works on lipids or fats (Table 1). soil organic matter and can be used effectively
One way of improving water and soil Enzymes are also naturally produced to manage soil quality and rearing conditions
quality in aquaculture and excreted by some for aquatic species. There is not one specific
is the direct application table 1: a diverse range of microbes. These extra- enzyme that works best in all cases (Ruggaber
of enzymes and ben- enzymes used as bioremediation cellular enzymes, such as and Talley, 2006). A blend containing a variety
eficial micro-organisms agents in aquaculture cellulase, protease and of enzymes may be the most effective means
to ponds. This type of enzyme Substrate amylase, are produced for bioremediation in aquaculture. The effi-
biotechnology applica- during the aerobic fer- cacy and mode of action of enzymes require
tion is often referred to amylase Starch mentation of organic mat- that they:
as ‘bioremediation’, an ter by micro-organisms, • Catalyse the degradation of organic
ß-Glucosidase ß-Glucoside
environmentally friendly for example by some matter (such as feces, undigested feed
approach which involves Cellulase Cellulose Bacillus species. Bacilli are and dead algae)
the manipulation of lipase lipids and fat commonly found in pond • Break apart large sludge particles
micro-organisms in ponds Protease Protein sediments and can also be (deflocculation) and reduce sludge
to reduce pathogenic Xylan, added to the pond water accumulation
bacteria, enhancing the Xylanase Hemicellulose for bioremediation pur- • Reduce solids content
mineralization of organic Pectinase Pectin poses. Some Bacillus sp. • Decompose plant debris
matter and removing are also able to degrade • Reduce anaerobic conditions in the
undesirable waste com- nitrogenous compounds pond bottom
pounds through specific enzymes. and their large variety of excreted (extracel- • Promote the degradation of certain
In the bioremediation process, enzymes lular) enzymes additionally helps to speed up complex nutrients
play the role of catalysts that accelerate the degradation of organic matter and toxic • Facilitate the release of highly digestible
biochemical reactions in pond soil and water. compounds such as ammonia. nutrients
36 | InternAtIonAl AquAFeed | July-August 2012

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4. FEATURE
quality of the
pond, and the
performance of
the cultured fish
and shrimp.
Studies have
confirmed that
ponds using bac-
terial strains and
enzymes showed
better soil condi-
tions (yellow soil)
Figure 1: Avergae growth rate of shrimp during Figure 2: Feed conversion ratio of control and enhanced
the production period and probiotic test groups
shrimp perform-
ance, while the soil
Enzymes strongly reduce sludge accu- (FCR) was improved by nine percent in of ponds without the treatment showed an
mulation and anaerobic conditions in pond the treatment compared with the control. accumulation of dead organic matter (black soil).
bottoms. They promote a faster degrada- The soil of the treatment ponds in The addition of specific enzymes (pro-
tion of the organic matter that accumu- Picture 1 was yellow, which is regarded as teases, amylases, cellulases, xylanases) and/
lates in ponds, especially under intensive the best bottom type, while the soil of the or enzyme-producing bacteria, such as
production conditions. This organic matter control ponds in Picture 2 exhibited a dark Bacillus sp., promotes the pre-digestion of
comprises uneaten feed, dead plankton, black color, an indication of the accumula- cer tain complex nutrients and facilitates
mineral soils, feces and pathogenic micro- tion of dead organic matter. the release of highly digestible nutrients.
organisms in the soil where the conditions Results suggested that with the com- This helps to reduce sludge and organ-
are often anaerobic. However, for all bined use of beneficial bacteria and ic matter accumulation, as well as the
these bioremediation processes catalysed enzymes, pond soils containing black and anaerobic conditions in pond bottoms,
by enzymes, the presence of beneficial glutinous organic sludge turned into a thus improving the rearing conditions for
bacteria is important as well (Boyd and more yellow soil. For the animals, enzymes shrimp and fish. ■
Gross, 1998). Enzymes accelerate microbi- improve the growth and performance of
al processes by breaking apart large sludge shrimp by balancing their ambient environ- More InforMatIon:
particles, thus creating more surface areas ment. BIOMIN
which can then be attacked and fermented The improvements of enzyme appli- www.biomin.net
by microbes. This reduction of sludge and cation may be
dead organic matter can be seen visually greater in ponds
not only through better water quality, but with even higher
also through better soil quality. stocking densities
and feeding rates
Combining bacteria where the water
and enzymes and soil quality
To test the effects of a combination deteriorate greatly
of beneficial microbes and enzymes on during the pro-
soil quality under practical pond condi- duction period.
tions, a field study was conducted using
a commercial probiotic product (2 x 10 9 Promising
CFU/g, AquaStar ® PondZyme, BIOMIN results
GmbH, Austria) containing an enzyme For the amel-
blend (amylases, xylanases, cellulases, pro- ioration of aquatic
teases) under intensive farming conditions environmental
for white shrimp (Litopenaeus vannamei) in conditions under
Zhuhai, China. intensive farming
Four earth shrimp ponds (0.7 – 0.8 ha/ operations, the
pond) with a depth of 1 – 1.2 m were combined applica-
stocked with juvenile shrimp (approxi- tion of enzymes
mately 1.4 g/shrimp) with a density of 50 and beneficial
shrimp/m². The trial was carried out for a bacteria as an
period of 57 days with a dosage of 500 g/ effective manage-
ha of product applied once a month to the ment tool seems
treatment group (two ponds). The control very promising.
ponds consisted of two ponds with normal Enzymes play
production operations. The shrimp in both important roles as
treatments received the same diets. biological control
Figure 1 shows that the average daily agents in pond
growth of shrimp in the treatment group culture, particu-
increased by 36 percent. It can be seen larly with respect
from Figure 2 that feed conversion ratio to water and soil
July-August 2012 | InternAtIonAl AquAFeed | 37

5. Aqua News
IFFO Backs Marine Mammal and Turtle
Conservation in South America
I
FFO (the International Fishmeal and Fish IFFO, said, “IFFO is delighted to see this
Oil Organisation) is backing an initiative excellent initiative from Camanchaca in
by one of its members, the Compañía Chile and indeed other recent develop-
Pesquera Camanchaca (Camanchaca), ments in South America regarding the
which aims to teach fishermen the art of quantification and avoidance of the inci-
environmental stewardship, better pro- dental catches of marine mammals and
tecting marine animals including dolphins, sea tur tles. In creating the IFFO RS
sea turtles and sharks. standard we were hopeful that this type
The initiative provides training for the of conser vation programme would be
senior crew who work aboard Camanchaca’s developed by our members and we look
vessels that land in the northern Chilean forward to hearing more good news in
port of Iquique. The scheme will contribute the future.”
towards the gathering of vital research The Chile based project follows one
information that will be used to help in the taken last year in Peru, in which a number
conservation of protected marine species. of fishing companies working with envi-
The first seminar took place during April ronmental NGOs such as the Marine
2012. Conser vation Society (MCS) and
IFFO has developed a Global Standard ProDelphinus distributed a series of turtle
for Responsible Supply (IFFO RS) for identification and resuscitation guides and
Fishmeal and Fish Oil. Its overarching pro- held a series of training courses.
gramme includes the goal to reduce any Dawn Purchase, Senior Aquaculture
potential environmental impact arising from Officer at MCS, said, “I am delighted with
fishing catches made within its responsibly the success of this project and the spin-off
managed fisheries. conservation courses being run for fish-
Camanchaca was one of the first com- ermen. The IFFO RS standard provides a
panies in Chile to have its factories cer- real opportunity to promote change on
tified under the IFFO RS standard earlier the water, which is what MCS strives to
this year. It has now formed a partnership achieve. Increasing the identification skills
with the Department of Marine Sciences of and conservation knowledge of these fish-
the Arturo Prat University and its Technical ermen in both Peru and Chile is a great
Training Centre, to offer specialised training way of achieving environmental steward-
seminars to the fishermen. ship”.
Large marine animals are sometimes
captured in the fishing nets designed to
catch small oily fish such as anchovy and
sardine, ingredients used in the pro-
duction of fishmeal for animal feed
and fish oil for human consumption.
IFFO is keen to ensure that its members
More InforMatIon:
are aware of the importance of conserving
Website: www.iffo.net
marine creatures as part of the marine eco-
system.
Topics covered at the seminars include IFFO
the ability to identify and correctly record The International
data on protected marine mammals found Fishmeal and Fish Oil
off the coast of northern Chile, as well as Organisation represents
learning how to safely return these crea- the fishmeal and fish oil industry
tures to the sea with the minimum risk of worldwide. IFFO’s members reside
damage. Mr Adolfo Carvajal, Camanchaca’s in more than 30 countries, account
Manager for the Northern Fishing Area, said, for two-thirds of world production
“Sustainable development requires us to and 80 percent of fishmeal and fish
take action in order to control the impact oil traded worldwide. Approximately
of our activities on the marine environment 5 million tonnes of fishmeal are
and without a doubt we have now under- produced each year globally, together
taken actions in this respect. These training with 1 million tonnes of fish oil.
seminars for our senior crew members will IFFO’s headquarters are located in St
allow them to demonstrate Camanchaca’s Albans in the United Kingdom and it
commitment to the responsible sourcing also has offices in Lima, Peru, and in
of fish”. Beijing, China.
Andrew Jackson, Technical Director at
July-August 2012 | InternAtIonAl AquAFeed | 7

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