In the past years, aquaculture industry has developed with great speed, which has also given rise to the wide applications of aquatic feed industry. Specially designed for aquatic animal breeding, aqua feed can be divided into fish feed, shrimp feed and crab feed according to feeding varieties, divided into pelleted feed and extruded feed on the basis of production process, and divided into mixed feed, concentrated feed and premixed feed in the light of fodder features. The raw materials of aquatic feed are mainly constituted of fish meal, cereal materials and grease, thereinto the previous two always account for over 50% of feed cost. Because fish have small intestines and stomach, lack of good digestion and absorption ability, the requirements on processing technique of fish feed are far higher than that of livestock feed, so it’s particularly important to choose suitable fish feed making machine and process.
Contrast of Pelleted Feed & Extruded Feed
With the development of processing craft, fish feed can be produced as pelleted feed and extruded aqua feed. Compared with natural feed, they have higher density and less humidity, not only allowing for long time reserve but decreasing the isolation of raw and processed materials. Although these two aquatic feeds have the same ingredients, there are obvious differences after put into water: pelleted feed sinks in water bottom while extruded feed floats on water within certain time due to their physical characteristics. Even if with the same formula, the cost of extruded aqua feed is higher than that of pelleted feed, but extruded feed can still create more benefits in virtue of its remarkable advantages.
Option of Pelleted Feed & Extruded Feed
The option of aquatic feed should consider the feeding characteristics and habits of different aquatic livestock. For instance, river crab and other benthic animals are accustomed to search food in water bottom and eat food very slow, so aquatic feed for them cannot be too hard, and the loss of fragment caused by biting food should be reduced as far as possible.
Then extruded sinking feed would be a better choice because it is convenient to soften and suitable to gnaw, reducing feed waste and water pollution with less fragment loss. Moreover, extruded aquatic feed has long water resistant time and high cultivated degree. Additionally, when the aquatic products market condition is well, using high-class pelleted feed or extruded feed can fatten fish quickly for selling on market as soon as possible. Feeding with those aquatic feed cannot only lower the occurrence rate of fish disease and make fish taste better, but also decrease waste of resources under the condition of fishing resources starvation day by day.
However, using extruded feed through whole feeding process can also lead to feed/meat ratio rising, bad sensitivity and intolerant for long distance transport. In adult fish phase, still continuing to use extruded fish feed can cause fish guano, big fish tripe and high moisture content in body so that customers are not willing to purchase.
In a word, during the process of fresh water aquaculture, the mixed using of pelleted feed and extruded feed can not only regulate water quality and reduce fish feed waste, but also improve the output of aquatic products, achieving the perfect combination of water quality control and economic benefits. Therefore, the combination of pelleted feed and extruded feed is the most significant feeding mode deserving to promote so far.