As aquaculture expert and nutritionist to animals and the development of feed nutrition, feed processing technology has made great progress, and the feed manufacturers for animal feed production requirements and cognitive also had obvious increase, making international needed for animal feed nutrition index is introduced into the domestic, some new feed processing technology was introduced into the domestic application and modified and extended. Selection of appropriate feed processing technology is conducive to the development of the breeding industry.
1 Feed processing technology
The specific feed processing technology is mainly defined as two types in academia. The first: raw materials are pulverized after the specific processing of ingredients. The second: the preparation process will be a certain proportion of ingredients and raw materials for grinding processing. In some cases, a mixture of the two processes may be used to meet specific nutritional needs. In the mixing process, the main indexes that affect the nutrient composition of feed and the performance of animals are mixing uniformity, crushing size and pelleting.
2 Effects of mixing process on feed production and feed main indexes
2.1 Mixing principle and the relationship between mixing uniformity
At present, China's manufacturers in the production of feed mainly impact, convection, shear, crushing, diffusion and other mixed methods. The movement mode of raw materials driven by the rotor of the mixer determines the mode of feed mixing. For example, a certain gradient between the rotors leads to the cutting of the mixture in a section type, resulting in the shear mixing mode.
2.2 Effects of mixing mode on feed production and main indexes of feed
International investigations on animal nutrition show that feed with high uniformity can improve animal productivity and feed absorption rate. In order to maintain the uniformity of feed, some chemical substances are added to preserve energy of feed. Chemicals can damage the animal's body and affect its performance. In the study of mixed feed for pigs, the conclusion is that the feed with low uniformity can obviously slow down the growth rate of pigs. The decrease in ketone secretions in pigs resulted from a significant decrease.
2.3 Factors affecting the uniformity of mixing
Mixing evenness have certain influence factors are: mixer machine and mixer rotor speed, mixing time of feed and the calculation formula of the number and the size of the fill factor, in the analysis process of concrete mixing uniformity of wear and tear on the machine's influence on the uniformity also determines the quality of the feed.
3 Effects of comminution on feed production and feed main indexes
3.1 Effects of pulverizing particle size on feed nutrient composition and animal performance
The crushing of raw materials will increase the area of raw materials, improve the chance of animal digestive enzymes to contact with feed, and promote the digestive efficiency of animals and the absorption efficiency of food nutrition. The increase of grinding size can improve the nutrient utilization rate of feed and nutrient intake of animals. Because different animals have different requirements for grinding size, appropriate grinding size has a corresponding impact on the efficiency of the production process. In the specific feed crushing machine selection process of hammer crushing machine can be the maximum strength of the feed crushing to improve the efficiency of feed crushing. Proper feed crusher is beneficial to improve the absorption of nitrogen element in feed. The specific twist adjustment of the grinder should also be adapted to different animal feed production. For the production of broiler animal feed crusher should be adjusted at about 700nm, but for the egg phase of the crusher should be adjusted at about 400nm.
3.2 Optimum grinding size of finished feed
When determining the grinding size of a feed product, it is adjusted according to different animals and their dietary habits. In the process of determining the corresponding optimal particle size, several animals were investigated in China. Among the national standards, the grinding size of chicken feed during egg production is required to be about 4mm, the grinding size of broiler feed production is required to be about 5mm, and the grinding size of pig feed production is required to be about 10mm.
4 Effects of pelleting on feed production and feed main indexes
The effects of pelleting on the production of feed have been shown in the relevant investigation: certain pelleting is beneficial to improve the digestibility of animal elements and promote the nutritional structure of feed. At present, there are two main forms of feed manufacturing for pelleting. One form is to use melted starch to wrap the feed to facilitate the decomposition of the feed, and the other is to use hydration heating and other means to destroy the original protein space of the starch in the process of making the feed to improve the digestion of the animal. These two ways of pelleting will have a certain impact on the nutrient composition of feed. The pelleting of feed is beneficial to the hydrolysis and absorption of feed, and the absorption of amino acids and trace elements has been promoted to a new level. The pelleting of feed can improve the performance and vitality of animals.
5 Effects of extrusion and puffing on feed production and feed main indexes
The puffing of feed can improve the digestion rate of amino acids to a certain extent. The puffing of feed increases the protein level rich in feed itself, which can promote its physiological metabolism. In the investigation of feed expansion at different temperatures, it is shown that the use of thermal expansion feed will reduce the probability of diarrhea in daily life of animals, improve the animal body function. The analysis of animal serum extract also showed that the utilization rate of nitrogen element was significantly increased after expansion.
