Supplementation of Pinus densiflora bark extract-chitosan composite improves growth performance, nutrient digestibility, intestinal health in weaned piglets

Abstract

Pinus densiflora bark extracts (PBE) improve the intestinal function and reduce the incidence of diarrhea in weaned piglets, but there is no significant change in growth performance due to the adverse effects of nutrient digestion. This study aimed to determine whether PBE-chitosan composite (PBE-CHT) overcomes these adverse impacts of PBE in weaned pigs and whether it has the potential to be a green and safe additive in weaned pigs. For this study, 90 crossbreed piglets [(Landrace × Large White × Yorkshire) × (Duroc × Pietrain)] with an average body weight of 8.12 ± 0.04 kg were randomly divided to 3 groups (basal diet (control), basal diet + 1500 mg/kg ZnO and basal diet + 500 mg/kg PBE-CHT) with 3 replicates per groups and 10 piglets per replicate during 28 days. The results showed PBE-CHT had the beneficial effect on the growth performance and reduced the diarrhea rate and diarrhea index significantly (p < 0.0001) compared with the control in weaned piglets. Moreover, compared with the control, PBE-CHT also significantly increased the trypsin activity in the pancreas and the duodenum (p < 0.05), resulting in the significant increase of the nutrients digestibility (p < 0.05). Meanwhile, PBE-CHT supplementation showed the significant increase of the villi height in duodenum, jejunum and ileum and the significant decrease of the crypt depth in duodenum and ileum (p < 0.05), and higher the mRNA expression levels of tight junction proteins (p < 0.01), while the contents of serum diamine oxidase and endotoxin in serum were significantly decreased (p < 0.05) compared to the control. Furthermore, PBE-CHT significantly improved the total number of bacteria in the digesta of the cecum, Lactobacillus counts and Bacillus counts in the digesta of the cecum and colon, and significantly decreased the number of E. coli in the digesta of the cecum and colon (p < 0.05). This study supported that PBE-CHT could improve growth performance, diarrhea incidence, and intestinal function in weaned piglets by reduction of PBE adverse impact on the digestive enzyme activity and the nutrients digestibility, providing a scientific and practical basis for the application of PBE-CHT in weaned piglets as a safe and practical feed additives.