First, the feed formulas of different manufacturers are different, and the types and quantities of raw materials used are very different, which is the main reason for the difference in feed prices and breeding effects. For example, the crude protein content of fish meal and corn gluten meal is basically the same, but the digestible protein of fish meal is much higher than that of corn gluten meal, and the amino acid composition of fish meal protein is more balanced, which is more suitable for the demand of aquatic animals for amino acids and has better breeding effect. Second, even the same feed formula, the same feed raw materials, due to the different processing technology and machinery, feed quality is also very different. Therefore, when we choose feed, we should not only look at the nutritional index of feed, but also compare it comprehensively from many aspects.