Citrus Extract Improves the Absorption and Utilization of Nitrogen and Gut Health of Piglets.

The purpose of this study was to investigate the effects of citrus extract (CE) on plasma free amino acids, intestinal morphology and enzymes activity, fecal nitrogen and phosphorus emissions in piglets. The experiment was performed on 144 weaned piglets (Duroc × Landrace × Large White) divided into three groups. Control (CON), fed a basic diet; Antibiotic (ANTI), fed a basic diet supplemented with 75 g/t chlortetracycline; Citrus extract (CE), fed a basic diet supplemented with 300 mL/t CE. The albumin content of the CE group was significantly higher than the CON group. Compared with the CON and ANTI groups, the CE group had increased concentrations of plasma total essential amino acids and threonine. Compared with the CON group, CE increased the α-aminoadipic acid concentration, while compared with ANTI group, it increased the 3-methylhistidine concentration. Compared with the CON group, the crypt depth of duodenum, jejunum and ileum decreased, and the ratio of villus height to crypt depth of ileum increased in the ANTI and CE groups. CE increased the activity of alkaline phosphatase and lipase in duodenum, and the activity of alkaline phosphatase and trypsin in jejunum. In brief, CE improved the absorption and utilization of nitrogen, intestinal morphology and digestive enzymes activity.