Application of glutamine derivative in preparation of animal feed additive

A glutamine derivative having a structure of formula (I), a racemate thereof, a stereoisomer thereof, a geometric isomer thereof, a tautomer thereof, a solvate thereof, or a feed acceptable salt thereof, for use in preparing an animal feed additive:

• wherein, Y is an OC1-C20 alkyl group or OH;
• X is a nitrogen-containing C4-C10 cycloalkyl group, a NHC1-C20 alkyl group, or a N(C1-C20 alkyl group)2;
• R1 is R1aC(═O), R1bC(═O), R1aS(═O)2, R1bS(═O)2, or H;
• R2 is R2aC(═O), R2bC(═O), R2aS(═O)2, or R2bS(═O)2;
• each of R1b and R2b is independently a C1-C20 alkyl group, a C3-C7 cycloalkyl group, or a C1-C20 alkyl group or C3-C7 cycloalkyl group optionally substituted with one, two, three, four, or five R3;
• R3 is —OH, —NH2, —CN, —SH, or —X1, wherein X1 is selected from F, Cl, Br, or I;
• each of R1a and R2a is independently a C5-C12 aryl group, a C5-C12 heteroaryl group, a —(C1-C4 alkylidene)-C5-C12 aryl group, a —(C1-C4 alkylidene)-C5-C12 heteroaryl group or, a C5-C12 aryl group, C5-C12 heteroaryl group, —(C1-C4 alkylidene)-C5-C12 aryl group or —(C1-C4 alkylidene)-C5-C12 heteroaryl group, optionally substituted with one, two, three, four, or five R4;
• R4 is —OH, —NH2, —NO2, —CN, —SH, —X2, a —C1-C5 alkoxy group, a —C1-C5 alkyl group, or a —C1-C5 alkyl group substituted with X2, wherein X2 is selected from F, Cl, Br, or I.