Feed Manufacture For Fish

   Feed manufacture involves grinding mixing, agglomeration, and forming feed ingredients into homogenous pellets that are water stable. Fry or small fingerlings as usually fed finely ground meal type feeds or pelleted feed that have been crushed to reduce particle. The bulk of feed used in the catfish industry is manufactured by extrusion into floating pellets. A smaller portion is team pelleted into sinking pellets.

 Regardless of the feed type, floating or sinking, the general scheme of feed manufacture is the same. The primary grains are ground through a hammer mill. The formulation is batched, weighed, mixed, and then reground. After regrind, the mixed-feed ingredients are extruded or steam-pelleted. The resulting pellets are then dried, fat-coated, and bagged or stored in bulk.

Feed Types and Feed Allowance

Types: floating versus sinking feeds.

FEEDSTUFF AND COMPOSITION

CARBOHYDRATE	CARBOHYDRATE	FATS	TOTAL PROTEIN	FIBRE
1.     Maize	60.0	4.5		2.1
2.     Wheat Bran	59.0	4.6	10.0	10.1
3.     Millet	48.0	4.4	7.3	8.7
4.     Condemned flour	70.0	3.9	32.0	2.5
5.     Rice bran	56.9	3.8	8.7	2.6
6.     Beer waste	46.4	7.8	22.3	18.8
7.     Mill sweepings	58.0	14.0	12.5	7.5
8.     Sorghum	81.0	2.8	9.0	3.0
9.     Sugar cane fibre	55.4	0.6	2.3	10.0
10.                        Cassava flour	83.3	0.5	1.9	1.7
PROTEIN	CARBOHYDRATE	FATS	TOTAL PROTEIN	FIBRE
1.      Soyabeans	31.4	15.7	33.7	5.5
2.     Groundnut cake	27.3	7.6	53.5	6.2
3.     Blood meal	1.5	3.5	61.0	0.0
4.     Cow stomach(dried)	37.6	1.9	26.7	8.2
5.      Fresh fish	0.0	1.5	21.2	0.0
6.     Fish meal	1.5	3.5	61.0	0.0
7.     Shrimps(dried)	4.4	5.5	53.3	0.0
8.     Silkworm pupae(dried)	6.6	24.5	35.9	0.0
FATS	CARBOHYDRATE	FATS	TOTAL PROTEIN	FIBRE
1.     Palm nutcake	53.0	8.0	38.9	14.0
2.     Full fat soya	31.4	15.7	33.7	5.5

Most cultured catfish, from fingerlings to market size, are fed a floating feed, which is preferred by the producer because of its management value. (The feeder can watch the fish for signs of disease and general wellbeing). Floating feeds remain at the surface for considerable periods of time and are not subject to loss in bottom mud as is sinking feed that also disintegrates quickly in the water. If the fish are feeding slowly, considerable feed waste can occur when sinking feeds are used. (Sinking feeds represent a small percentage of feed fed a catfish.)

Particle Size

Increase feed-particle size as fish increase in size. Fry and fingerings catfish are fed finely ground meals or larger particle sized crumbles. (Feed small fingerlings a crumble or a small sized floating pellet and large stocking-size fingerlings a large floating pellet.

HOMEMADE FEEDS: Homemade feeds can satisfy the nutritional needs of catfish farm. Locally available feeds must be fully investigated to determine their potential nutritional value in the diet. These inexpensive animal protein formulation demonstrate how locally available products may be adapted to produce an economical fish food. Whether pelleting is possible or not, dough of the soya cake or offal/corn should be made and the chicken intestine is washed, mashed and mixed with the other ingredients and then pounded or chopped using a knife or meat shrewder that will extrude strands of material which is broken into pellet form.

STORAGE AND QUALITY

Nutritional quality required by fish depends on the stocking rate. High quality fish must be given in heavy stocked ponds. When lower stocking rates are used, the fish can use naturally occurring feeds in the pond party as well as added feed.

FEEDING ADVANCED FINGERLINGS TO HARVESTABLE-SIZED FISH

Typically, a 32% protein floating feed is fed to large fingerlings to harvest. Sinking feeds can be used, but management is more difficult when sinking pellets are used. Most catfish producers prefer a flosting feed. Feed the fish in the morning, after dissolved oxygen levels have started to rise and no later than midafternoon, to allow for digestion during periods of relatively high dissolved oxygen. Fish do not consume and assimilated feed efficiently when the oxygen levels are low.

STORAGE OF PELLET FEEDS FOR FISH ON A FARM  

Since feed constitute the major operating cost in most aquaculture operations, it essential that its effectiveness in not impaired by careless handling after manufacture, especially as a result of improper storage.

Various factors can contribute to losses in quality of feeds during storage. These include:

(1) Environmental factors like rain

(2) Condensation

(3)       High temperature and

(4)       Sunlight

(5)       Theft

(6)       Fire and

(7)       Scavenging animals such as rats and birds can cause significant losses of feed

(8)       Infestation by insects and

(9)       Fungi

(10)        Enzymatic reactions and

(11)        The development of oxidative rancidity can also cause serious deterioration in        feed quality.

In view of the foregoing, it is important that feeds be properly handled and stored to obtain the maximum benefit from them.

The following are some guidelines:-

(1)     Feed should be stored in a day, cool and well-ventilated place. A proper, well-insulated and secure building should be provided for feed storage. Care should be taken to ensure that rain and surface water does not enter the store. Ventilation points (windows are not recommended) should be provided; the ventilation points should be low on the side facing prevailing winds and high on the opposite side. All entry points should be meshed entry by rodents and other pests.

Feeds should not be stored for longer than two months on-site. Vitamins and liquid quality will deteriorate with time. Ideally, feeds should be purchased and utilized on a monthly basis.

Feeds should be stacked not more than five bags high. The stacks should be placed away from the walls. This ensures adequate air circulation between feed bags to maintain consistent moisture and temperature levels. Large stacks of bags cause heat generation with other consequential adverse effects.

Feed should be stored on wooden pallets and not directly on concrete floors or in contact with concrete walls. Concrete surfaces, being usually cooler than the surrounding air, cause moisture in the feed to migrate to the cool area. Thus, the part of the feed that is in contact with the concrete floor or wall will accumulate moisture which encourages growth of mould and spoilage.

Feed should not be stored in direct sunlight. Temperature changes in the feed between the day and night encourage spoilage. Sunlight also affects vitamin and liquid quality adversely.

The feed stored must be kept clean. Floors and walls should be regularly swept. Spilled materials must be removed and the contents of broken bags should be used first.

The first in and first out FIFO principle must be applied, that is the oldest stocks should be used first spoiled or expired feed should , however not be used.

Staff should not be allowed to eat, sleep or smoke in the store. Strict stock control rules must be practiced.

While close attention must be paid to proper storage to feed, it is also of great importance to verify the quality of the feed at the time of delivery to ensure that good quality feed is received. This includes checking on the date of manufacture of the feed batch and also the water stability, signs of insect attack, tancidity, and so forth. Testing for water stability is done by stirring a sample of feed in a container of water (preferably taken from the culture pond) and noting the ability of the feed pellets to retain their form. A good feed should be able to remain intact in water for 2-4 hours.

If the above precaution on the delivery and storage of feeds are followed, there should be minimal deterioration in their quality, thus ensuring that the culture organisms are receiving feed of good quality.

Feeding rates are affected by numerous factors, including crop, water quality, and water temperature. In the multiple stocking, multiple harvest program employed by many catfish producers, the number of fish and standing crop are usually high and fish size is variable, In this type of program, Fish are selectively harvested by using seine with a mesh size that allows sub marketable fish to pass through the seine while capturing the harvestable-sized fish. Fingerlings are then stocked into the pond to replace fish that are removed. To ensure adequate feed for all fish, the producer must offer ample feed but should be careful to add only as much feed fed may be high as 6kg per acre per day, and most producer feed once daily. Feeding twice a day is beneficial, but on large commercial catfish farms, it is almost impossible to feed twice a day averagely.

Feeding Allowance

Feeding allowance for catfish may be expressed as a percentage of body weight or as kilogram of feed fed per acre per day. Feeding is most affected by fish size and water temperature, with smaller fish eating more feed in relation to their size and feeding more frequently than larger fish.

If feeding allowance is based on a percentage of body weight, the amount of feed that should be fed changes daily. If you decide to feed by a percentage of body weight, adjust weekly. Know the weight of fish at stocking and assume a feed conversion ratio (2 pounds of feed per pound of grain is a good consumption for fish reared on commercial catfish farms), or sample the fish and base biomes on sample weight.  The second method is more accurate, but sampling is problematic because it is time consuming and may stress the fish.