Objective   Effects of a highly reduced crude protein diet supplemented with glutamate (Glu) and arginine (Arg) on the intestinal metabolites and microbiota of weaned piglets were examined for aquaculture feed formulation.

  Method  One-hundred-ninety-two healthy (26±2)-day-old crossbred (Duroc × Landrace × Large White) piglets with an average body weight of (6.96±0.29) kg were randomly divided into 4 groups. Each group contained 6 replicates of 8 piglets each. Group I (CK) was fed on the control diet that provided 21.16% crude protein (CP). Group II was on a low-protein diet containing 15.97% CP supplemented with some limiting amino acids. Added to the Group II diet, 1.50% Glu was included for feeding Group III and 1.50% Glu plus 1.00% Arg for Group IV. From 11^th to 13^th day in the 16 d feeding program, metabolites and microbial community in the piglet intestines were monitored.

  Result  The fecal putrescine and spermidine of the treatment piglets were similar but significantly lower than those of CK (P＜0.05). The cadaverine in the Groups II and III piglets showed no significant differences but were significantly lower than that of CK or Group IV (P＜0.05), and that of Group I significantly lower than that of Group IV (P＜0.05). No significant differences were observed on the fecal acetic acid and propionic acid among all groups (P＞0.05), but the butyric acid in the piglets of all treatment groups was significantly higher than those of CK (P＜0.05). The intestinal microbiota richness and diversity of the animals under treatments were significantly higher than those of CK (P＜0.05). At phylum level, the relative abundance of Firmicutes in the fecal microbiota of the piglets were significantly higher under the treatments than CK (P＜0.05), but those of Bacteroidetes and Proteobacteria significantly lower than CK (P＜0.05). Significant differences were also observed among the groups at family and genus levels. The relative abundances of unspecified families and unspecified genera under clostridiales were significantly higher under the treatments than CK (P＜0.05), those of prevotellaceae, enterobacteriaceae, and lachnospiraceae were significantly lower under the treatments than CK (P＜0.05), those of lachnospiraceae, lactobacillaceae, blautia, and lactobacillus of Group IV significantly higher than those of CK (P＜0.05), and those of peptostreptococcaceae and terrisporobacter of Group IV were significantly lower than those of CK (P＜0.05).

  Conclusion  A forage of CP being reduced from 21.16% to 15.97% and supplemented with Glu and Arg lowered the intestinal biogenic amines, increased the butyric acid, and enhanced the diversity and richness of microbiota in the weaned piglets.