Effect of dietary supplementation with protease on growth performance, nutrient digestibility, intestinal morphology, digestive enzymes and gene expression of weaned piglets

This study was conducted to investigate the effect of dietary protease supplementation on the growth performance, nutrient digestibility, intestinal morphology, digestive enzymes and gene expression in weaned piglets. A total of 300 weaned piglets (21 days of age Duroc × Large White × Landrace; initial BW = 6.27 ± 0.45 kg) were randomly divided into 5 groups. The 5 diets were: 1) positive control diet (PC), 2) negative control diet (NC), and 3) protease supplementations, which were 100, 200, and 300 mg per kg NC diet. Results indicated that final BW, ADG, ADFI, crude protein digestibility, enzyme activities of stomach pepsin, pancreatic amylase and trypsin, plasma total protein, and intestinal villus height were higher for the PC diet and the supplementations of 200 and 300 mg protease per kg NC diet than for the NC diet (P < 0.05). Supplementations of 200 and 300 mg protease per kg NC diet significantly increased the ratio of villus height to crypt depth (VH:CD) of duodenum, jejunum and ileum compared with NC diet (P < 0.05). Feed to gain ratio, diarrhea index, blood urea nitrogen, and diamine oxidase were lower for the PC diet and supplementations of 200 and 300 mg protease per kg NC diet than for the NC diet (P < 0.05). Piglets fed the PC diet had a higher peptide transporter 1 (PepT1) mRNA abundance in duodenum than piglets fed the NC diet (P < 0.05), and supplementations of 100, 200 and 300 mg protease per kg NC diet increased the PepT1 mRNA abundance in duodenum (P < 0.05) comparing with the NC diet. Piglets fed the PC diet had a higher b0,+AT mRNA abundance in jejunum than piglets fed the NC diet (P < 0.05), and supplementations of 200 and 300 mg protease per kg NC diet increased the b0,+AT mRNA abundance in jejunum and ileum comparing with the NC diet (P < 0.05). In summary, dietary protease supplementation increases growth performance in weaned piglets, which may contribute to the improvement of intestinal development, protein digestibility, nutrient transport efficiency, and health status of piglets when fed low digestible protein sources.