Ferosekhan. S

FNB-41

AQUAFEED STORAGE – PROBLEMS AND SOLUTIONS

INTRODUCTION

Losses occurring in feedstuffs during storage fall under four major categories 1) weight loss,

2) quality loss, 3) health risk, and 4) economic loss.

These losses arise from

i. the foraging activities of insects, ii. micro-organisms and animals, iii. improper handling, iv. physical and chemical changes.

Storage loss in a feed mill is due to insect ,animal pests and fungi .

CONT…

Intense insect activity often results in mould growth and it leads to complete destruction of the feedstuffs

also poses serious health risks to animals or fish feeding on rations containing damaged feed ingredients

When serious infestation by these pests occurs there is extensive weight loss accompanied by damage to quality

The lack of quality standards reflects in feed commodities

qualities.

INSECTS

Insects feed on most feed ingredients and contaminate them with faeces, webbing, body parts, foul odours, and micro-organisms

Beetles and moths are the most destructive of the grain insects, and many are capable of destroying an entire store of feed.

Some insects are not discriminatory in their feeding habits whereas others are highly selective in their feeding

For example,

1) Moth larvae generally feed on or near the surface of the grain mass, 2) Beetles are destructive throughout.

WEEVILS

Acorn weevil

Blue WeevilClover leaf weevil

Stout Weevil

Species

Susceptible feedstuffs

Minimum for increase to epidemic numbers

Optimum range for increase

Scientific name

Common name

Temp, °C Rel. Hum, % Temp, °C

Sitophilus spp.

Weevils Cereal grains 15 50 26-30

Sitotroga cerealella

Grain moth Cereal grains 16 30 26-30

Tribolium spp.

Flour beetles Cereal grains and cereal by-products, oilseed cakes

and meals, finished feed 21 * 30-33

Oryzaephilus spp.

Saw-tooth grain beetles

Cereal grains and cereal by-products, oilseed cakes and meals, finished feed 21 10 31-34

Cryptolestes spp.

Flat grain beetles

Cereal grains and cereal by-products, oilseed cakes and meals, finished feed

21 50 30-33

Cadra cantella

Tropical warehouse moth

Cereal grains and cereal by-products, oilseed cakes and meals, finished feed

17 25 28-32

Rhizopertha dominica

Lesser grain borer

Cereal grains, pulses, dried roots 23 30 32-35

Trogoderma granarium

Khapra beetle

Cereal grains and cereal by-products, oilseed cakes and meals, finished feed, pulses

24 * 33-37

FACTORS AFFECTING INSECT INFESTATION OF FEEDSTUFFS

The occurrence and development of an insect infestation is dependent on

source of insects, available food, temperature, moisture, air, condition of the feed-stuff, presence of other organisms

Major factors affecting insect population growth is temperature, relative

humidity, and moisture, content of the feed ingredient.

LOSSES DUE TO INSECT ATTACK

The best warning of serious weight loss is the presence of a large insect population.

Loss may be aggravated by prolonged storage.

Failure to keep the storage area clean and retention of infested sweepings will increase the liability of insect attack.

Weight loss Quality loss

CONTROL

Climate is the most important factor determining the effectiveness of a storage system

close relationship between insect growth and ambient climatic conditions

Total eradication of insects in tropical climate is tedious one but we can control it’s population through GMPs

Better should not carry any infested feed materials into the storage room before proper fumigation has been done.

MICRO-ORGANISMS

Micro-organisms are biological contaminants of the natural environment and are present in all feedstuffs

Post-harvest processing of feed materials such as heat, chemical and mechanical extraction, and dehydration eliminate most of the native micro flora

Fungi spores are highly resistant in nature . Once fungi has grown on the feed it is better to avoid that feed for feeding the fish.

These organisms are cause more harm to the fishes.

FACTORS AFFECTING FUNGAL GROWTH IN FEEDSTUFFS

Factors can influence the growth of Fungi

1. Temperature ( 25-35°c)2. Humidity ( 70-90% )3. Moisture ( 15-20% )

The most common fungi involved in the spoilage of feedstuffs belong to the Aspergillus spp. and the Penicillium spp.

They are most destructive when temperatures exceed 25°C and relative humidity exceeds 85 percent.

DETRIMENTAL EFFECTS OF STORAGE FUNGI ON FEEDSTUFFS

The chief effects of storage fungi on feedstuffs are:

(a) mycotoxin production,

(b) heating and moisture increase,

(c) mustiness (staleness).

MYCOTOXIN PRODUCTION

Mycotoxins are compounds produced by fungi growing in infested feed materials

They are toxic to both humans and animals.

Aflatoxins:

A group of highly toxic and carcinogenic metabolites produced by Aspergillus flavus are perhaps the most important among mycotoxins contaminating feedstuffs.

Cont…

Transmission of the toxin from feed to animals/fish through feeding on contaminated feed poses an increasing health hazard.

Studies on the toxicity of aflatoxin to fish have not been extensively studied.

Aflatoxin toxicity to trout (oral LD50: 0.5 mg/kg body weight) is reported.

In fishes, it causes decreased feed intake, reduced growth, tumor formation, and eventually mass mortality.

OTHER MYCOTOXINS

Cont…

Feedstuffs known to be contaminated by A. flavus include:

1. groundnut cakes,

2. maize,

3. sorghum,

4. sunflower,

5. cottonseed cakes,

6. copra, and

7. cassava.

Cont…

To produce aflatoxin, A. flavus must be present in a pure culture form.

The presence of other fungi, yeast, or bacteria seems to interfere with aflatoxin production.

Crops such as peanuts, cottonseed, and copra are high aflatoxin risks precisely because A. flavus often infest them as a practically pure culture with few or no other microflora.

In addition, the fungus produces the toxin in these crops at relatively low moisture levels, 9 to 10 percent, compared with 17 to 18 percent moisture for most feed grains.

Feed grains such as maize and sorghum grown in the tropics, therefore, also pose high risk.

DISCOLOURATIONS

Feedstuffs that are damaged by fungi tend to become lumpy.

Feed grains exhibit discolouration due to fungal action.

Maize turns a dark brown with some blackened kernels because of fungi growth.

Also exhibits a bluish discolouration .

CONTROL MEASURES

Aflatoxins are not inactivated by normal pelleting process.

Use of Mycotoxin binder (Mycosorb- Alltech)

Prevention of mould growth is the best means to avoid contamination of feed ingredients.

Removal and disposal of mould-damaged material is essential in preventing contamination.

DETERIORATIVE CHANGES IN STORED FEEDSTUFFS

Rancidity ( Lipid Oxidation):

Rancidity resulting from lipid oxidation is the most important deteriorative change occurring in stored feedstuffs.

Feedstuffs containing lipids which are highly unsaturated (e.g., rice bran and fish meal), are especially susceptible to oxidation.

The mechanism of lipid oxidation begins with auto-oxidation involving the direct reaction of lipids with molecular oxygen to form hydroperoxides.

This is followed by secondary reactions yielding diperoxides

Fission of hydroperoxides yield products containing carbonyl and hydroxy groups which will react further to form other products.

STEPS IN FAT OXIDATION

PREVENTION OF RANCID OXIDATION OF FATS

Blocking of Hydrogen supply

Addition of anti-oxidant such as Vit-E and Vit-C

Avoid direct contact with oxygen

DO S AND DON’T S IN FEED STORAGE ROOM

Provide a building storage that is secured and adequately locked.

Don’t accept deliveries of raw materials that are visibly damped.

Purchase required quantity of ingredient so that you do not need to keep great quantity in stock.

Always keep the store clean.

Make small stack.

Ensure that ingredients are clearly and neatly labeled.

Don’t walk over the feed bags.

CONT…

Feed should not be stored in direct sun light. This would adversely-affect the vitamin and lipid quality of the feed.

Feed should be used within 2-3 months of manufacturing.

Feed should be stored on wooden spacers not more than 5 bags high to maintain air circulation.

Feeds store should be 100% water proof and damp proof.

Proper ventilation should be provided.

Dry feed should be stored under cool and dry condition with temperature of < 20°c and humidity < 70%.

CONCLUSION

In a culture system, feed is the most important key factor that influence the production cost.

This feed should be stored at proper controlled condition, so that the quality of feed is not affected.

Good feed storage should provide protection against high temperature, humidity, moisture and insect and rodent infestations.

Feedstuffs should, as far as possible, be stored for a minimum length of time. Prolonged storage leads to deterioration of feed quality.

Storage never enhances feed quality, but proper storage reduces the deleterious changes in feed quality.