Effects of copper-loaded chitosan nanoparticles on intestinal microflora and morphology in weaned piglets

The objective of the present study was to investigate the effects of dietary supplementation with copper-loaded chitosan nanoparticles (CNP-Cu) on growth performance, intestinal microflora, and morphology in weaned piglets. A number of 90 weaned piglets (Duroc × Landrace × Yorkshire), weaned at 21 days with body weight of 7.2 ± 0.81 kg, were randomly divided into three groups by weight and sex, each treatment including three replicates of ten pigs. The piglets were fed the same basal diet supplemented with 0 (the control group), 100 mg/kg CNP-Cu, and 100 mg/kg chlortetracycline (the positive group). The results showed that 100 mg/kg CNP-Cu significantly increased average daily gain and feed intake and decreased feed/gain ratio and diarrhea rate (P < 0.05). Compared with the control group, the amount of Escherichia coli in duodenum, jejunal, and caecum were significantly decreased by 100 mg/kg CNP-Cu; the number of lactobacillus in jejunal and caecum were increased (P < 0.05), and the amount of bifidobacterium in duodenum and caecum were also increased (P < 0.05). Moreover, the villous height of duodenum, jejunum, and ileum mucosa was significantly increased (P < 0.05), and the crypt depth was significantly decreased (P < 0.05). The results indicated that CNP-Cu is beneficial to growth and intestinal microflora and morphology and could be a potential substitution of chlortetracycline in diets of weaned piglets.