According to rough statistics, the available agricultural and animal husbandry by-products resources in China are as high as 1.645 billion tons, including agricultural and by-products residue based on crop straw, food industry residue, animal derived waste and kitchen waste. The comprehensive utilization rate of these non grain protein sources is not high, and the main restrictive factors include:

1. low level of resource collection and serious waste; 2. some resources contain toxins or anti nutritional factors, and the system reduction technology of toxic and harmful substances is not perfect, which reduces the nutritional value of feed and affects animal growth and health; 3. the extraction and separation technology of non grain feed protein resources is applied to a low degree, or the cost of some technologies is too high, which makes it difficult to apply and promote in the feed industry; 4. at present, the balance between protein titer and amino acid in feed can not meet the needs of animal growth, resulting in a waste of a large number of protein resources. The utilization level of non grain protein source can be improved through shell kernel separation technology, extrusion technology, enzyme bacteria co fermentation technology, ultra-fine grinding, membrane separation technology and so on.

At present, the application sources of non grain protein sources in aquatic feed mainly include: 1 Animal protein feed resources (terrestrial animal products and their by-products, fish and other aquatic animals and their by-products); 2. plant protein source and its processed products; 3. microbial protein feed resources; 4. dregs and their by-products; 5. new non grain protein sources (Clostridium ethanol protein, methane thalli protein, Tenebrio molitor, black water Tabanus, algal protein).