a comprehensive account on nutrients involved in pond fish farming - koushik roy and hena...

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.

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International Journal of Research in Fisheries and Aquaculture

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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.


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.


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.


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


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

a comprehensive account on nutrients involved in pond fish farming - koushik roy and hena...

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