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Objectives

The objectives of this experiment were:-

1. To determine the pH, and turbidity of water sample from catfish pond owned by Aroma

Spice.2. To determine the biochemical oxygen demand of water sample from catfish pond owned

by Aroma Spice.

3. To study of aquaculture of catfish.

4. To identify the moisture content from the different kind of fish pellet that use by Aroma

Spice.

5. To identify the percentage of protein in the different kind of fish pellet that use by Aroma

Spice.

6. To study of Kjedhal method.

Introduction

Catfish are a diverse group ofray-finned fish. Nowadays the agriculture of catfish

becomes popular. This is due to high market demand. They also easy to handle and care. Catfish

can easily live in any condition. Catfish content high of omega 3 that good for health. Many

canning product can produce from the catfish meat. Like Aroma Spice take this advantage on the

market potential of catfish. They do agriculture of catfish in their own building and then makethe product from catfish and release it to market. In order to make sure to get a good quality of

catfish, it still need to have a very good care of the catfish.So some parameter need to be focus

like turbidity,pH, biochemical oxygen demand (BOD) level, protein in feed and other.

BOD is the amount of oxygen required by aerobic microorganisms to decompose the

organic matter in a sample of water, such as that polluted by sewage. It is used as a measure of

the degree of water pollution. Turbidity is used to know the cloudiness of the water. High

turbidity affects the aesthetic appeal of waters, and in the case of recreational areas may obscure

hazards for swimmers and boaters. Its environmental effects include a reduction in light

penetration which reduces plant growth, and in turn reduces the food source for invertebrates and

fish. If turbidity is largely caused by organic particles, their microbial breakdown can lead to

oxygen depletion.

The pH scale ranges from 014 which is 0 is very acidic and 14 are very alkaline.

Freshwater usually has pH values between 6.5 and 8.2. Most organisms have adapted to life in

http://en.wikipedia.org/wiki/Actinopterygiihttp://en.wikipedia.org/wiki/Fishhttp://en.wikipedia.org/wiki/Actinopterygiihttp://en.wikipedia.org/wiki/Fish

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water of a specific pH and may die if it changes even slightly. The pH level can be affected by

industrial waste, agricultural runoff or drainage from unmanaged mining operations.

Nitrogen is one of the five major elements found in organic materials such as protein.

Kjedhal method is used to determine the amount of protein in samples taken from a wide variety

of organisms. The central basis used in this procedure is the oxidation of the organic compound

using strong sulfuric acid. As the organic material is oxidized the carbon it contains is converted

to carbon dioxide and the hydrogen is converted into water. The nitrogen, from the amine groups

found in the peptide bonds of the polypeptide chains, is converted to ammonium ion, which

dissolves in the oxidizing solution, and can later be converted to ammonia gas. The Kjeldahl

method of nitrogen analysis is the worldwide standard for calculating the protein content in a

wide variety of materials ranging from human and animal food, fertilizer, waste water and fossil

fules.

Material and apparatus

- Nitrification inhibitor

- Sample water from catfish pond

- Dilution water

- Beakers

- BOD bottles

- Analytical balance

- Dissolved oxygen test meter

- Micropipette

- Dry fingerlings and growth pellet

- Hydrochloric acid- Boric acid

- Distilled water

- Kjeldahl distillation, titration, and digestion

- Moisture content analyzer

- Conical flask

- Beaker

- Pipette

- Analytical balance

- Test tube

- Sulphuric acid- Kjetabs tube

- Sodium hydroxide

- pH meter

- Turbidimeter

- Mortar and pestle

- Aluminium place

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- Moisture analyzer

Methodology

Dissolved Oxygen (DO) and Biochemical Oxygen Demand

1. The sample water of catfish pond was determined.

2. 200 ml of the sample was placed into the BOD bottle.

3. 0.16 g of nitrification inhibitor (BOD inhibitor) was weighed and added into the samples.

4. The sample was refilled with 100 ml distilled water and stirred.

5. The initial DO level (ppm) of the sample and its duplicate was recorded by using the

dissolved oxygen test kit.

6. The sample was placed in an incubator at 20 for 5 days.

7. On day 5, final DO reading (ppm) was taken by using the dissolved oxygen test kit with

the fan switched on until the BEEP sound was heard indicates the measurement was

complete.

8. The BOD5 level was determined using equation below:

Where:

pH

1. Water sample was put into the beaker.

2. The sensor of pH meter was inserted into the water sample. The pH meter needs to be

calibrated first before used.

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3. Button Read was pushed.

4. The reading was observed and recorded.

Turbidity

1. The turbidimeter was calibrated first.

2. The tap water was put into tube and measured its turbidity as blank.

3. Water sample was taken from beaker and put into the tube.

4. The tube was cleaned gently in order to make sure the tube is dried.

5. Then, the water sample was inserted into the box of turbidimeter and button Read was

pushed.

6. The reading was observed and recorded.

Protein determination using Kjedhal method

1. 2g of the small pellet was weighed by using analytical balance then place in test tube.

2. 2 tube of Kjeltabs and 12mL of sulphuric acid was added into test tube. For the blanks

just only put 2 tube of Kjeltabs and 12mL of sulphuric acid. Make the sample duplicate

and repeat the method above by using large pellet.

3. Then place all the test tube into the Kjedahl digester at 420oC for 1 hour 15 minute.

4. After finish the digestion, let it cooled about 20 minute.

5. Next, the sample was added with 80mL of distilled water.

6. 25mL of acid boric was prepared in conical flask.

7. The sample and the acid boric was place at Kjedhal distiller for the distillation process for

about 5 minute.

8. After distillation process finished, the conical flask was use for titration process.

9. A 50 mL pipette was filled to the top with 1.1M hydrochloric acid.

10.The hydrochloric acid was pipette into conical flask until the solution turn slightly grey,

and then stopped the titration process.

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Moisture content

1. The fish pellet was grinded with mortar and pestle.

2. 2g of the grinded pellet was placed in the aluminium place and run in the moisture

analyzer at temperature 100 oC.

3. The weight of the pellet was taken every 1 minute until 5 minute and the percentage ofthe moisture was obtained.

Result

Table 1: Value of pH, turbidity and BOD5 of water from the catfish pond.

Measurement Reading

pH 5.96

Turbidity (NTU) 11.5

Turbidity of tap water (NTU) 1.85

BOD5 (mg/L) 19.02

Table 2: Moisture content of fingerlings catfish pellet.

Fingerlings catfish

pellet

Replicate 1 Replicate 2 Replicate 3

Initial Final Initial Final Initial Final

Weight (g) 2.028 1.823 2.046 1.855 2.032 1.845

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Moisture content (%) 10.11 9.34 9.20

Mean moisture

content

9.55

Table 3: Moisture content of growth catfish pellet.

Growth catfish pellet

Replicate 1 Replicate 2 Replicate 3

Initial Final Initial Final Initial Final

Weight (g) 2.034 1.842 2.020 1.848 2.037 1.869

Moisture content (%) 9.44 8.51 8.25

Mean moisture

content

8.73

Table 4: Test data of fingerlings catfish pellet.

Sample data Replicate 1 Replicate 2 Replicate 3

Sample weight, A (g) 2.0450 2.0405 2.0001

Amount HCl used,

Vsample (mL)

45.2 68.9 68.5

Amount HCl used,

Vblank(mL)

0.1 0.1 0.1

Normality HCl, Nacid

(N)

0.1078 0.1078 0.1078

Table 5: Percentage protein of fingerlings catfish pellet.

Test data Replicate 1 Replicate 2 Replicate 3

%N = 3.3300 5.0911 5.1638

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% protein = (f %N) 20.8125 31.8194 32.2738

Mean of protein 28.3019

Table 6: Test data of growth catfish pellet.

Sample data Replicate 1 Replicate 2 Replicate 3

Sample weight, A (g) 2.023 2.027 2.321

Amount HCl used,

Vsample (mL)

18.9 4.1 18.1

Amount HCl used,

Vblank(mL)

0.1 0.1 0.1

Normality HCl, Nacid

(N)

0.1078 0.1078 0.1078

Table 7: Percentage protein of growth catfish pellet.

Test data Replicate 1 Replicate 2 Replicate 3

%N = 1.4032 0.2980 1.1710

% protein = (f %N) 8.77 1.8625 7.3188

Mean of protein 5.9838

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Discussion

The sample of the pellet and water was taken from Aroma Spice Company. They do the

agriculture of Africa catfish. They do the agriculture in the close building. They have 3 ponds

named A, B and C that according to the size of catfish. Pond A and B is for fingerlings catfish

that the size of pond was height = 3m x length = 10 ft x width = 5 ft and the total volume was

14m3. Total fish that can be put on pond A was 3000 while pond B was 2000. Pond C is for

growth catfish that the size of pond was height = 3m x length = 15 ft x width = 20 ft and the total

volume was 83.6m3. Total fish that can be put on pond C was 6000. The water sample was used

to determine the pH, turbidity and biological oxygen demand (BOD) while the pellet was used to

identify the percentage of protein moisture content. The result was discussed below.

The pH is measure of the relative amount of free hydrogen and hydroxyl ions in the

water. Water will become acidic when free hydrogen ion is high while water will become base

when high of free hydroxyl ions. Based on the result on Table 1, by using the pH meter, pH of

water sample from Aroma Spice catfish pond was 5.96. In theory catfish can tolerate high

concentrations of carbon dioxide (up to 100 ppm) in blood so they can withstand in acidic pH but

not below 5. Therefore, this water sample is suitable for catfish to live because it is not too acidic

besides it contains enough of dissolved oxygen. Too acidic of water will give bad effect to

organism for live and it also effect the environment. The pH of water usually was affected by

several factors. One of the factors is the amount of plant growth and organic material within a

body of water. When this material decomposes carbon dioxide is released. The carbon dioxide

combines with water to form carbonic acid. Although this is a weak acid, large amounts of it will

lower the pH.

Turbidity is the measurement of the cloudiness of the water and the unit for turbidity is

Nephelometer Turbidity Units (NTU). The higher value of turbidity, it showed that the harder to

see through the water. From the Table 1, it can see that the turbidity of the water sample from

Aroma Spice catfish pond was 11.5 NTU and by the observation the water look like less

cloudiness. The tap water turbidity was 1.85. This is due to the company will make sure the pond

in circulated of the water. In theory, when the value of turbidity of water increases, it means the

water quality is low and consists of many substances such as mud, silt, sand, bacteria, aquatic

organisms, algae, and chemical precipitates. Such particles absorb heat in the sunlight, thus

raising water temperature, which in turn lowers dissolved oxygen levels. That mean this water

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sample has good quality for the catfish. This less cloudiness is due to make the worker to easy to

choose the good catfish while do the harvesting process. Lights ability to pass through water

depends on how much suspended material is present. Turbidity of this water sample has less

substance that blocked the light to pass through the water. Turbidity may harm fish and their

larvae. It is caused by soil erosion, excess nutrients, various wastes and pollutants, and the action

of bottom feeding organisms which stir sediments up into the water.

Microorganisms such as bacteria are responsible for decompose organic waste. When

organic matter such as dead plants, leaves, grass clippings, manure, sewage, or even food waste

is present in a water supply, the bacteria will begin the process of breaking down this waste.

When this happens, much of the available dissolved oxygen is consumed by aerobic bacteria,

robbing other aquatic organisms of the oxygen they need to live. Biological oxygen

demand (BOD) is a measure of the oxygen used by microorganisms to decompose the waste. If

there is a large quantity of organic waste in the water supply, there will also be a lot of bacteria

present working to decompose this waste. In this case, the demand for oxygen will be high due to

all the bacteria so the BOD level will be high. As the waste is consumed through the water, BOD

levels will begin to decline. In most cases, if dissolved oxygen concentrations drop below 5

mg/L, fish will be unable to live for very long. All clean water species such as trout or salmon

will die well above this level and even low oxygen fish such as catfish will be at risk below 5

mg/L. In the theory, the 8mg/L 30mg/L is the range of the BOD 5 that suitable for organism and

aquatic animal to live. From Table 1, the BOD5 of water catfish sample from Aroma Spice was

19.02 mg/L. So the sample was in the range of the good condition of fish living.

Feeding is the most important in the intensive pond production of catfish. In a normal

situation, catfish can be seen only when they are coming up to feed, and their feeding behavior

can be an important clue to general health and the pond condition. Potential problems with the

fish or pond water quality can be recognized early by noticing abnormal feeding behavior. Feed

used in pond culture of catfish must be nutritionally complete. Feed must contain all essential

nutrients at adequate levels to meet total nutritional requirements of catfish for normal growth

and health. The fingerlings feed should be small in size of pellet so that they can eat easily, while

for growth catfish was vice versa.

In this experiment, the protein content of the pellet that use at Aroma Spice was

determine by using Kjedhal method. Based on the Table 5 and Table 7, the protein content for

fingerlings pellet was 28.3% while for the growth pellet was 5.98 %. It is slightly lower from the

protein content that stated on the packaging (min 32% protein) of the fingerlings catfish pellet.

Based on the journal found, for good growth the fingerlings catfish pellet should has 32% of

protein while for the growth catfish pellet should has about 28% - 30% of protein. The

http://www.ciese.org/curriculum/dipproj2/en/fieldbook/oxygen.shtmlhttp://www.ciese.org/curriculum/dipproj2/en/fieldbook/oxygen.shtml

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fingerlings catfish need more protein because they faster growth compared to growth catfish. On

the fingerlings stage they need protein for the muscle growth and it help in the formation of fish

meat.

On the packaging of the fingerlings catfish pellet it stated that the maximum moisture

content of the pellet was 12% and from the experiment the result was 9.55%. It is still in the

range of the packaging. Growth catfish pellet has moisture content 8.73%. In the theory, the

moisture content for dry pellet should have 10%. Determination of moisture content is important

for the storage condition. If the pellet has high moisture content it will let to microbial growth

that can make the pellet harm. Low moisture content has low density so the pellet will easily

float at the surface of the water.

Conclusion

The pH of water sample was 5.96 which are suits for catfish living. Meanwhile its

turbidity is 11.5 NTU compared to tap water which is 1.85 NTU. This is cause from the silt of

water, suspended solids and waste from fish. Also, it is not suit for drinking because it is harder

water. The BOD5 level was 19.02 mg/L that still in range of the suitable water for organism and

aquatic animal to live. This showed the water is in good quality. Two kind of pellet was in range

of moisture content but for the protein percentage was not in the range that should the catfish

feed for good growth.

References

- Fish species, Catfish.2009.Retrieved on 15 Feb 2011 from

http://fish.mongabay.com/catfish.htm

- Professor John Blamire,Kjedhal Method, 2003. Retrieved on 13 Feb 2011from

www.scienceAdistance.com

- Technology of seed production. Retrieved on 14 Feb 2011 from

http://www.fao.org/docrep/field/003/AC378E/AC378E07.htm

- Biological oxygen demand, 2011. Retrieved on 15 Feb 2011 from www.eNotes.com

- G.C. Delzer and S.W. McKenzie, (1998), Five-Day Biochemical Oxygen Demand, BOD5

Test Procedure

- American Society of Civil Engineers/American Water Works Association (1990), Water

Treatment Plant Design (2nd Ed.) Mc. Graw Hill, International, USA, 1990, p. 1-10.

http://fish.mongabay.com/catfish.htmhttp://www.sciencea/http://www.fao.org/docrep/field/003/AC378E/AC378E07.htmhttp://www.enotes.com/http://fish.mongabay.com/catfish.htmhttp://www.sciencea/http://www.fao.org/docrep/field/003/AC378E/AC378E07.htmhttp://www.enotes.com/

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