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International Journal of Research in Fisheries and Aquaculture 2014; 4(4): 150-155. A COMPREHENSIVE ACCOUNT ON NUTRIENTS INVOLVED IN POND FISH FARMING - Koushik Roy and Hena Chakraborty
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150 International Journal of Research in Fisheries and Aquaculture 2014; 4(4): 150-155
ISSN 2277-7729
Original Article
A COMPREHENSIVE ACCOUNT ON NUTRIENTS INVOLVED IN POND FISH FARMING
Koushik Roy1* and Hena Chakraborty2
1Faculty. Department of Industrial Aquaculture and Fisheries. Asutosh College (second campus), University of Calcutta,
Kolkata – [email protected] 2 Postgraduate scholar. Department of Aquaculture Management and Practices. Vidyasagar University
Received 29 August 2014; accepted 01 October 2014
1. Introduction
Nutrients are inorganic elements and/or their derivatives
naturally occurring in the environment in various forms
which are obligatorily utilized by living systems (plants,
animals, microbes) for the purpose of :-
a. Growth and reproduction. (e.g.- Proteins).
b. Synthesis of organic products. (e.g.- Hormones,
enzymes).
c. Formation of biomass. (e.g.- Tissue/ cell from N, P, C,
H, O, S).
d. Maintaining body metabolics. (e.g.- Anabolism,
catabolism).
2. Types of Nutrients (According to Source)
According to source, there are 3 categories of nutrients
involved with fish culture viz.-
a. Fertilizer and organic derived nutrients.
b. Nutrients fixed in biomass.
c. Food nutrients.
3. Source and Sink of Nutrients 3.1. Fertilizer and organic derived nutrients
Source Sink
i. Inorganic fertilizers
(E.g.- urea, ssp, etc.)
ii. Organic manures (E.g.-
FYM, Animal excreta,
etc.)
iii. Benthic sediments
(E.g.- Bottom muck,
silt, etc.)
iv. Dead and decaying
organic matter (E.g.-
Decomposing feed,
dead plants/animals,
etc.)
v. Run-off from adjacent
fields &catchment
areas
i. Utilization by
primary
producers.
ii. Assimilation by
secondary &
tertiary
consumers.
iii. Lost into the
atmosphere or
surrounding
environment.
iv. Locked or
trapped within
benthic
sediments.
3.2. Nutrients fixed in biomass Source Sink
i. Feed (E.g.- Natural, supplementary,
artificial)
ii. Absorption from environment (E.g.-
Through skin, gills
& during osmoregulatory
processes)
i. Proteins & enzymes. ii. Carbohydrates
iii. Lipids
iv. Vitamins, minerals & hormones.
3.3. Food nutrients
Source Sink
i. Natural food (E.g.-
Phytoplankton, plants,
zooplankton,
bacterioplankton)
ii. Supplementary feed
(E.g.- larval feed,
grow out feed,
broodstock feed.)
iii. Detritus
i. Fixed into biomass
or standing crop.
ii. Lost through
harvested biomass
or crop.
iii. Recycled into
environment by
bacterioplankton.
iv. Locked or trapped
within benthic
sediments.
4. Types of Nutrients (According to Quantity)
According to quantity, there are 2 categories of nutrients
involved with fish culture viz.-
4.1. Macro-nutrients (required in larger quantities, i.e.- in
Kg, gm, etc.) :
Nitrogen (N), Phoshphorus (P), Pottasium (K), Inorganic
carbon (C), Sulphur (S), Calcium (Ca), Hydrogen (H),
Oxygen (O)
4.2. Micro-nutrients (required in minute quantities, i.e.- in
mg, µg, I.U., etc.) :
Iron (Fe), Cobalt (Co), Copper (Cu), Chlorine (Cl), Boron
(B), Selenium (Se), Chromium (Cr), Molybdenum (Mo),
Zinc (Zn), Manganese (Mn), Sillicon (Si), Sodium (Na),
Magnesium (Mg), Vitamins A,D,E,K, B-complex, C,
Choline, Inositol, biotin, etc.
Available online at http://www.urpjournals.com
International Journal of Research in Fisheries and Aquaculture
Universal Research Publications. All rights reserved
151 International Journal of Research in Fisheries and Aquaculture 2014; 4(4): 150-155
5. Direct and Indirect Impact of Nutrients in Aquatic
systems
Having discussed the direct impacts of nutrients on the
aquatic flora and fauna already (see above, section 3), let us
discuss the indirect impacts of supplementing nutrients in
aquaculture:-
The primary production of ponds & lakes is strongly
limited by nutrient availability. Increased nutrient input
therefore leads to enhanced lake productivity, with
cascading effects on the remaining trophic levels and the
interactions between these (Jeppesen, 1998).Thus in many
ponds & lakes, during the 20th century, the input of
phosphorus and nitrogen from urban communities and
agriculture triggered a shift from a clearwater state with
submerged macrophytes (as the most significant primary
producer) to a turbid state with phytoplankton (as the
dominant primary producer) (Körner, 2002; Jeppesen et al.,
2005a).
Simultaneously, marked alterations occurred in fish and
zooplankton population structure, which again affected the
grazing control on phytoplankton (Jeppesen et al., 1997a,
2000). On the contrary, algal blooms or eutrophication will
occur in the presence of excessive nutrients.
In nutshell it can be said that – “moderate” level of
nutrients enhance, replenish, or increase the abundance of
natural fish food organisms. Furthermore it strikes a
balance in the ‘miniature’ ecology created/already existing
within farm ponds.
6. Nutrient replenishment pathways in ponds
There are 2 pathways of Nutrient replenishment in fish
ponds, which are given below: -
6.1. Fertilisation of water body
Since nutrient depletion is often experienced in fish
farming ponds, pond fertilization has become imperative to
maintain optimal nutrient level and hence sustained fish
production. Inorganic fertilizers and organic manures are
used to enhance fish production in the pond system.
Combinations of inorganic and organic fertilizers are
preferred since the blends seem to promote a wide variety
of both autotrophic and heterotrophic organisms. (Das &
Jana, 1996).
6.2. Dietary replenishment
Moreover, Dietary nutrient requrement (Proteins, Essential
amino acids, Lipids, Essential fatty acids, Non protein
energy, Water & Fat soluble vitamins & minerals) of
cultured aquatic animals are met through supplementary or
balanced feeding. The feed consisting of Protein
supplement, Energy supplement, roughage, Vit-Min
fortifying agents and other additives. (Harver, 1998).
7. Key environmental nutrients in fish culture ponds
7.1. Phosphorus (P)
Of the three primary nutrients, phosphorus (P) is the most
scarce in the natural environment. The availability of
phosphorus is frequently considered as being the single
most important factor for the overall environmental state of
lakes. (Boyd, 1971).
7.1.1. Sources
Weathering of phosphorus containing rocks, Phosphate
fertilizers, Agricultural and urban drainage, Atmospheric
dust, Animal waste, Decomposition of organic matter.
7.2.2. Forms
Once in the pond, P can be very dynamic (Hepher, 1958;
Hepher, 1966; Syers et al., 1973). To best understand P
dynamics let us recognize the different forms in which P
can be found.
P can be found either in Particulate form or in a Soluble
form.
Particulate forms can either be Organic particulates, such as
phytoplankton, zooplankton, bacteria, fish, or detritus.
Inorganic particulates are P adsorbed (i.e., attached by
chemical/ionic bonding) to suspended soil colloids, or as
precipitates formed with phosphate (PO4) + Iron (Fe),
Aluminum (Al), [at low pH] and Calcium (Ca) [at high pH]
(Knud-Hansen, 1998).
Soluble P is also found in both organic and inorganic
forms. The organic form consists of dissolved organic
molecules such as polypeptides, enzymes (e.g., alkaline
phosphatase), adenosine triphosphate (ATP), and
organophosphates released into the water through
decomposition, excretions, and exo-enzymatic secretions
from algae, bacteria, fungi. Inorganic forms of dissolved P
are principally orthophosphate (PO4) and, to a lesser
degree, polyphosphates. (Knud-Hansen, 1998).
7.2.3. Dynamics of P
The recycling of P between dissolved and particulate forms
through uptake, excretion, secretion, and decomposition
benefits algal productivity (Brabrand et al.,
1990).Biological competition for P, is complicated by the
two chemical processes of Adsorption and Precipitation,
which can take soluble P out of solution.
The aim in culture ponds, of course, is to get as much
‘fertilizer-P’ into algal biomass as possible.
Fig. 1: Phosphorus cycle in ponds.
7.2. Nitrogen (N)
Nitrogen is a major component of proteins and amino acids,
and is, after C, H, and O, the most abundant element in
living cells.Nitrogen typically occurs in concentrations
much higher than those of phosphorus.Despite that the
demand by primary producers for nitrogen is much higher
than for phosphorus, there will often be a nitrogen surplus
in the pond environment.
7.2.1. Sources
Fertilisation, Precipitation, Run-off, N-fixing algae,
Decomposition of organic matter and Seepage.
7.2.2. Forms
i. Particulate Organic: - Found in living biomass and
detritus.
152 International Journal of Research in Fisheries and Aquaculture 2014; 4(4): 150-155
ii. Soluble Organic: - Nitrogenous materials are
released into the water from excretions, secretions,
and decomposition processes.
iii. Soluble Inorganic: - Ammonium (NH4+) ions
adsorbed to suspended sediments.
iv. Particulate Inorganic: - Nitrate (NO3-), nitrite
(NO2-), ammonia (NH3/NH4
+), and nitrogen gas
(N2).
7.2.3. Dynamics
The three primary N molecules utilized for algal growth are
ammonia, nitrate, and nitrogen gas (Fogg, 1975; Bold and
Wynne, 1978). Essentially all algae can take up nitrate and
ammonia. Both algae and bacteria incorporate
ammonia/nitrate very rapidly.In addition, some algae can
metabolize various forms of dissolved organic N, as well as
remove ammonium ions adsorbed to suspended particulate
matter (Knud-hansen, 1998).
Ammonia is the principal nitrogenous by-product of
organic decomposition. In waters containing dissolved
oxygen, ammonia not incorporated by algae can be
oxidized (i.e., add oxygen) through microbial processes.
The oxidation of ammonia first to nitrite and then to nitrate
is called nitrification. In this two-step process, the
microbial transformation of ammonia to nitrite
(Nitrosomonas sp.) is much slower than the subsequent
microbial transformation of nitrite to nitrate (Nitrobacter
sp.) (Cavari, 1977; Goldman and Horne, 1983).This is
essentially an oxygen consuming process. Hence takes
place in aerobic conditions only. It releases H+ ions in the
process. Hence the pond should have a strong buffering
capacity.
Fig. 2: Nitrogen cycle in ponds.
7.3. Carbon (C)
Carbon is the dominant element in organic matter. Primary
producers such as algae incorporate inorganic carbon, while
secondary producers such as fish incorporate organic
carbon from other biological sources (e.g., algae, algae-
derived detritus, zooplankton).
7.3.1. Sources
Solution of atmospheric CO2, Dissolution of the common
rock limestone and Decomposition of organic matter.
7.3.2. Forms
Carbon dioxide (CO2), Bicarbonate (HCO3-) and Carbonate
(CO32-).
7.3.3. Dynamics
Two things happen when CO2 is added (e.g.- respiration,
aerobic decomposition) and dissolves into water. First,
bicarbonate and carbonate are produced. Second, hydrogen
ions (H+) are released, making the pH drop (acidic).When
carbonate is added (e.g.- lime/CaCO3), bicarbonate and the
hydroxyl ion (OH-) are produced.When bicarbonate is
added either from carbonate or added independently (e.g.-
sodium bicarbonate/NaHCO3) produces CO2 and another
OH- molecule.The H+ produced with the addition of CO2
and the OH- produced with the addition of CO32- and HCO3
-
demonstrate the important role of pH in carbon equilibria.
When CO2 is produced through respiration or
decomposition, total DIC concentrations increase and the
corresponding release of H+ causes a decrease in pH.Algal
uptake/removal of CO2 during photosynthesis increases
OH- concentrations and raises the pH of the water. Algae
utilize CO2 and bicarbonate (HCO3-), but not carbonate
(CO32-).
7.4. Hydrogen (H) and Oxygen (O2)
H & O2 are among the chief components of organic
molecules after C. These are abundantly present in our
environment. By default, these are met into the pond
ecosystem by the water itself and by diffusion of
atmospheric or photosynthetic oxygen into water.Water is
obtained through precipitation, filling and percolation. It is
lost through evaporation, transpiration, discharge and
seepage.
Aquatic flora and fauna utilize water as a medium for body
fluids and metabolic/biochemical processes. Oxygen is
used as the chief respiratory gas and for facilitating aerobic
decomposition of organic matter.
Fig. 3: Hydrogen (in the form of water) and Oxygen cycle
in ponds.
7.5. Potassium (K)
Potassium is the other essential nutrient for plant growth.In
tropical ponds, it is easily abundantly available both in soil
and water and does not form insoluble salts and is rarely
deficient except in acid peaty soil (Boyd, 1970). Yet, a little
potassium when added to the pond stimulates the
production of plankton.
It majorly exists in pond as soluble monovalent cation i.e.-
K+. It occurs in the pond either as free exchangeable K+
and/or K+ adsorbed on soil/clay colloids.
7.6. Sulphur (S)
Sulphur is a component of a couple of vitamins and
essential metabolites and it occurs in two amino acids,
cysteine and methionine.
153 International Journal of Research in Fisheries and Aquaculture 2014; 4(4): 150-155
Like nitrogen and carbon, the microbes like
Desulfovibriodesulfuricans can transform sulphur from its
most oxidized form (sulphate or SO4) to its most reduced
state (sulphide or H2S).
Two unrelated groups of prokaryotes oxidize H2S to S and
S to SO4. The first is the anoxygenic ‘photosynthetic purple
and green sulfur bacteria’ that oxidize H2S to S. The
second is the ‘colorless sulfur bacteria’ which oxidize S to
SO4.However, in either case, the organisms can usually
mediate the complete oxidation of H2S to SO4.Sulfur is
assimilated by bacteria and plants as SO4.
8. Functions of some key nutrients in biological systems
Element Source Function
Carbon organic compounds or
CO2 Main constituent of cellular material
Oxygen H2O, organic compounds,
CO2, and O2
Constituent of cell material and cell water; O2 is electron
acceptor in aerobic respiration
Nitrogen NH3, NO3, organic
compounds, N2
Constituent of amino acids, nucleic acids nucleotides, and
coenzymes
Hydrogen H2O, organic compounds,
H2 Main constituent of organic compounds and cell water
Phosphorus inorganic phosphates
(PO4)
Constituent of nucleic acids, nucleotides, phospholipids,
LPS, teichoic acids
Sulphur SO
4, H
2S, S, organic
sulfur compounds
Constituent of cysteine, methionine, glutathione, several
coenzymes
Potassium Potassium salts Main cellular inorganic cation and cofactor for certain
enzymes
Magnesium Magnesium salts Inorganic cellular cation, cofactor for certain enzymatic
reactions
Calcium Calcium salts Inorganic cellular cation, cofactor for certain enzymes and a
component of endospores
Iron Iron salts Component of cytochromes and certain nonheme iron-
proteins and a cofactor for some enzymatic reactions
9. Nutrient cycling in a fish culture pond
Fig. 4: Nutrient cycling.
10. Principles of Pond Fertilization
Input of nutrients through inorganic sources has long been
a common practice of pond fertilization.Limitation of algal
growth is best described by Liebig’s Law of the Minimum,
which says that algal productivity will be limited by the
element present in least supply relative to algal
requirements (Knud-hansen, 1998) Note that this principle
says “least supply” and not “least concentration.”
The concept of pond fertilization should be based on NPC
rather than NPK (as practised in agricultural soil with less
organic matter) (Das, 1996). Many interacting factors such
as soil type, water depth, water retention time, species of
culture, quality and quantity of vegetation should be taken
into consideration. The environmental consequences of
over-fertilization resulting in pollution and subsequent
hazards in public health should be taken into account.
154 International Journal of Research in Fisheries and Aquaculture 2014; 4(4): 150-155
Fig. 4: Pathways of fertilisers in a fish culture pond
10.1. Fertilizer types
i. Inorganic: e.g.- Urea, SSP, DSP, DAP, MOP, etc.
ii. Organic: e.g.- Animal wastes, Green manure, Compost, etc.
10.2. Comparison of organic and inorganic fertilizers
Organic fertilizers Inorganic fertilizers
Storage Difficult, only short time Easy, possibly for long time
Distribution Difficult, esp. on larger scale Easy
Mineral content Variable, low Consistent, high to very high
Organic matter Present Absent
Effect on soil structure Improvement No
Direct food for fish Yes No
Decomposition process Yes, with oxygen consumption No
Price Low to medium High to very high
Cost per nutrient unit Higher Lower
Availability Possibly in neighbourhood or even on own farm Commercial suppliers only; sometimes imported
Direct pond fertilization Possible by raising animals on or near the pond Not feasible
10.3. Ideal Fertility Indices of Fish ponds (WATER)
Desirable concentrations for
good algal production:
Phosphates
> 0.2 mg/l
Total P > 0.4 mg/l
Nitrates
> 2 mg/l
Total N > 1.5-3 mg/l
Potassium
> 1 mg/l
Oxygen
> 4 mg/lit
Best P:N ratio = 1:4 to 1:8 Total alkalinity
60 – 400 ppm
Total Hardness
40 – 300 ppm pH – 7.5 to 8.5
Source: ICAR, 2011
10.4. Soil based classification and fertilisation recommendation of fish ponds.
Pond Types
(Productivity)
Soil Organic Carbon
(%)
Available Nutrients
(mg/100g)
Nutrient requirement
(Kg/ha)
Quantity of fertilizer or manure
required
(Kg/ha/yr)
Low Below 0.5 N: below 25
P2O5: below 3
N: 200-250
P2O5: 100-125
Org. C: 600-720
Urea @225-290
SSP@315-405
Cow dung@ 10000-12000
Medium 0.5 – 1.5 N: 25 - 50
P2O5: 3 - 6
N: 150-200
P2O5: 75-100
Org. C: 480-600
Urea @156-225
SSP@219-315
Cow dung@ 8000-10000
High 1.5 – 2.5 N: above 50
P2O5: above 6
N: 100-150
P2O5: 50-75
Org. C: 300-480
Urea @112-156
SSP@156-219
Cow dung@ 5000-8000
Source: Das & Jana, 1996
155 International Journal of Research in Fisheries and Aquaculture 2014; 4(4): 150-155
11. Nutrients in feed
Essential nutrients such as protein, fat, carbohydrate,
vitamins and minerals are required as raw materials for the
formation of body tissues, production of energy and also to
regulate the vital physiological processes.
The background knowledge of the nutritional requirement
of concerned fish species becomes essential for formulation
of suitable balanced supplementary feed.
11.1. Proteins
Protein requirements may be looked at the gross protein
and specific amino acid requirement levels. Protein
requirement is influenced by several factors like water
quality, natural food availability in ponds, dietary protein
quality, the amount of non-protein energy in the diet,
stocking density, etc. If the protein quality (amino acid
profile) is good and if the diet contains adequate energy
from non-protein sources (Lipids, Carbohydrates), then
“Sparing of Protein” occurs. As a result, highly efficient
utilization of dietary proteins at economical levels becomes
possible. Ultimately this protein is used solely for growth
(Halver, 1998).
Minimum protein requirement in a fish diet: 25-
30%
Herbivorous & Omnivorous species: 30-38%
Carnivorous species: 38-50%
Energy yield of protein: 3.6 kcal/g dry wt.
Protein (mg): Energy (kcal) ratio is the most
crucial factor in fish diets. Around 90-100 mg/kcal
is required for fry/fingerlings and 80-90 mg/kcal is
required for juveniles/adults.
11.2. Lipids
Lipids are important source of energy, essential fatty acids,
phospholipids and provide a vehicle for absorption of fat
soluble sterols & vitamins. These also play a vital role in
the structure of cell, cellular membrane, serves as pre-
cursors of several hormones and prostaglandins (Halver,
1998).
Lipid requirement in fish diet: 5-15% of dry feed
wt.
Optimum level: 7-10% of dry feed wt.
Phospholipid: 4% of total lipid
Sterol/Cholesterol: 0.5% of total fat
Energy yield of Lipid: 9.4 kcal/g dry wt.
The polyunsaturated fatty acids (PUFA) is
considered to be the most important class of lipids
as far as lipids are concerned. For F.W. Fish: n3-
linolenic acid & n6-linoleic acid is essential.
For S.W. fish: n3 - eicosapentaenoic acid and n6-
docosahexanoic acid is essential.
11.3. Carbohydrates
Fishes do not have specific dietary requirements for
carbohydrates. But they are always included in fish diets as
they are the cheapest energy source and also acts as pellet
binder.They serve as precursors of various metabolic
intermediates. Carbs have a lipid and protein sparing effect.
Hence its excess quantity in feed is avoided (Halver, 1998).
Carbohydrate requirement in fish diet:
Herbivores & Omnivores: 22-30% of dry feed wt.
Carnivores: <20% of dry feed wt
Energy yield of Carbohydrate: 4.1 kcal/g dry wt.
11.4. Vitamins
Vitamins are required in trace amounts but their deficiency
causes serious metabolic disorders. They are essential for
fish growth and to fight against disease. They are required
for metabolism of other nutrients in tissue. Most of the
water soluble vitamins acts as co-enzymes.They are of two
types: Fat soluble vitamins and water soluble vitamins
(Halver, 1998).
Vitamin pre-mix requirement in fish diet: 1% of
dry feed wt.
References
1. Adhikari S. 2003. Fertilization, soil and water quality
management in small-scale ponds, Aqua-asia magazine
vol: Oct-2003
2. Boyd, C.E. 1976. Chemical and textural properties of
muds from different depths in ponds. Hydrobiologia,
48: 141-144.
3. Boyd, C.E. 1986. Water quality and fertilization. In:
Aquaculture of Cyprinids, Billard, R. and J. Marcel,
(eds.), INRA, Paris, p. 282-295.
4. Das S.K., Jana B.B. 1996. Pond fertilization through
inorganic sources: an overview. Indian J. Fish., 43(2j:
137-155, Apr.-Jun.
5. Halver E.J. 1998.Textbook on Fish nutrition (2nd
Ed).Academic press. USA.
6. ICAR.2011. Handbook of fisheries & aquaculture,
ICAR publ., New Delhi.
7. Knud-hansen. 1998. Pond Fertilization: Ecological
Approach and Practical Application. SARC publ.
8. Søndergaard M. 2007. Nutrient dynamics in lakes–
with emphasis on phosphorus, sediment and lake
restoration. D.Sc. Doctor’s dissertation. Danish
University.
Source of support: Nil; Conflict of interest: None declared