Abstract: A fish-derived peptidoglycan recognition protein mutant and an application thereof are provided. An amino acid sequence of the mutant is shown in SEQ ID NO. 1, a nucleotide sequence of the mutant is shown in SEQ ID NO. 2. The present disclosure provides the preparation method for the mutant with a broad-spectrum antibacterial activity and robust inhibitory effects on both Gram-positive and Gram-negative bacteria. Compared with the wild-type LcPGRP5 protein, the mutant protein demonstrates a stronger ability to inhibit the activity against Staphylococcus aureus and enhance the phagocytic ability of fish macrophages.

Abstract: A fish-derived peptidoglycan recognition protein mutant and an application thereof are provided. An amino acid sequence of the mutant is shown in SEQ ID NO.1, a nucleotide sequence of the mutant is shown in SEQ ID NO.2. The present disclosure provides the preparation method for the mutant with a broad-spectrum antibacterial activity and robust inhibitory effects on both Gram-positive and Gram-negative bacteria. Compared with the wild-type LcPGRP5 protein, the mutant protein demonstrates a stronger ability to inhibit the activity against Staphylococcus aureus and enhance the phagocytic ability of fish macrophages.

Abstract: The present disclosure relates to a feed additive for improving intestinal structure of Larimichthys crocea, a feed and use, and belongs to the field of aquatic animal nutritional feeds. The feed additive includes glyceryl monolaurate. The present disclosure further provides a feed containing the feed additive, and a mass percentage of the glyceryl monolaurate in the feed is 0.04%. The present disclosure further provides use of the feed additive in improving the intestinal structure of the L. crocea, and the use lasts for at least 70 days. The feed provided by the present disclosure can effectively improve intestinal morphological change, reduced intestinal villi, reduced intestinal perimeter ratio, and intestinal barrier damage caused by replacement of fish oil with soybean oil; and damage of intestinal antioxidant activity caused by replacement of fish oil with soybean oil is relieved.