What is Fat/Oil Coating for Animal Feed?
Both animal fats and plant oils can be added to feed pellets and the addition of animal fats and plant oils in animal feed with proper amounts is an effective method to improve the feed quality. And the process of adding fats/oils can be set before pelletizing or after pelletizing. The volume of addition before pelletizing should not be more than 3% of the production, or it will lead to pellets of loose character, and this kind of fat/oil adding is not so working for extruded feed pellets production, but it has low-level technical demand for the process equipment. The maximum fat/oils adding volume can be 8% after pelletizing, which is the so-called fat/oil coating, improving productivity without affecting the solidness of pellets, working well for producing extruded animal feed and having a high-level standard of equipment.
Advantages of Fat/Oil Coating Animal Pellet Feed
Pellet feed fat/oil coating can be done during feed pelletization, or after feed pellet grading. And there are many advantages of fat/oil coating feed pellets.
1. Increasing additive content greatly
Fat/oil coating is done after pelletizing, so the oil ratio in pellets can be increased enough without influencing the pellet solidness.
2. Reducing cross contamination
Because it employs a post-pellet liquid addition process, reducing the residual oil on the processing equipment, then reducing the danger of cross-contamination.
3. Supplying essential fatty acid
Fat/oil supplementation has many benefits, including providing calories for weight gain and providing essential fatty acids to improve skin and coat conditions.
The essential fatty acid mainly linoleic acid, linolenic acid, and arachidonic acid which can be compounded by linoleic acid. Its primary function is to facilitate phospholipid metabolism, and its lack can lead to animal skin cornification, blood vessel embrittlement, and growth blocking.
4. Extra energy effect
The use ration of pellet feed is increased after adding fat/oil, and the reason could be the fat/oil prolongs the standing time of chyme in animals’ digestive tract, improving the nutrient’s digestibility. The fatty acid can be directly deposited in animal bodies, reducing the energy cost of fatty acid deposition by dietary crude protein and carbohydrates.
5. Helping fat-soluble vitamin absorption
The fat-soluble vitamin must be dissolved in the fat/oil to be absorbed by the animal intestinal tract, and if there is not enough fat/oil, the fat-soluble vitamin absorption will not be good, which will weaken animals’ growth and immunity.
6. Improving the animal capability of anti-heat-stress
The heat increment of fat/oil is lower than protein and carbohydrate, which reduces unnecessary heat dissipation consumption. Heat stress will make livestock production decline, but adding fat/oil is good for livestock production.
7. Improving the feed quality
Spray the fat/oil materials on the pellet feed betters feed physical property and palatability, and the fat/oil materials have penetrability, they can permeate into feed pellets deeply during the further process and transportation, ensuring well-mixing and quality, diminishing the feed particle dispersion and dust, increasing feed intake and conversation rate and stability in the water. So the feed pellet with fat/oil spraying can keep a good livestock production performance. Also, coating of the pellet makes animal feed attractant and reduces abrasion.
8. Increasing sales revenue
Upgrading feed pellets by coating them with fats and oils gives these pellets higher quality and therefore higher prices, so it is possible to expand the range of premium products, enter new customer circles, and generate higher profits.
Major Factors Affecting Fat/Oil Coating Quality
1. Temperature: low temperature of fat/oil for coating will reduce fat/oil viscosity, cause fat/oil globules, affect fat/oil fluidity and atomization effect, then result in an uneven coating.
2. Spray nozzle: spray nozzle structure and mounting position have a direct effect on fat/oil atomization result and coating evenness.
3. Feed pellet size and flow direction: small-sized and high-density feed pellets with even eddy motion can get uniform fat/oil coating and absorption.
4. Feed pellet solidness: the feed pellet without high solidness will bring about the fat/oil layer peeling off and feed powder, causing nutrient wastage.
5. Control system: the coating control system should be perfect and monitored properly to avoid scrap feed that is caused by oil leaks and flow direction changes.
Effective Fat/Oil Coating Technology and Equipment
Post pellet liquid application (PPLA) technology has been widely used in the feed liquid coating process, including fat/oil coating, since the early 1980s. Because liquid coating after animal feed pelletization prevents the heat-sensitive components in the feed from the damage of thermal processing facilities, such as feed pelletizer, feed extruders, etc., thus ensuring feed quality and reducing feed cost.
In terms of working principle, fat/oil coating equipment has a vacuum infusion coater, spraying atomization coater, and centrifugal atomization coating machine, these three types.
1. Vacuum infusion coater: it is a vacuum within the coater, and when the dry material is rolling-over and moving, the fat/oil that is sprayed into the coater is absorbed by the loose structure of the dry material.
2. Spraying atomization coater: fat/oil is micro-granulated by the sprayer and then sprayed to the feed surface.
3. Centrifugal atomization coating machine: centrifugal motion is employed to micro-granulate fat/oil to coat the feed pellet.
And electrostatic coating is another feed pellet coating technology introduced from food processing technologies that are used to add micro-ingredients to basic foodstuffs. It makes the atomized liquid like fat/oil complete pellet feed coating efficiently.