Effect of dulcitol on growth performance, antioxidant activity, immune function, and intestinal microflora of growing-finishing pigs

Dulcitol (DUL) has multiple biological functions such as anti-inflammatory, antioxidant, and anti-cancer. However, little is known about the DUL used in swine diets. This experiment investigated the effects of DUL on the growth performance, apparent digestibility of nutrient, blood profiles, and fecal microbiota of growing-finishing pigs. A total of 144 barrows (initial body weight (BW) of 30.1 ± 0.7 kg) were blocked based on BW and assigned to 4 dietary treatments in a 72-d trial, each treatment had 6 replicate pens and 6 pigs per pen. Dietary treatments included a control (CON) diet and 3 DUL diets with DUL supplementation at the concentration of 100 (DUL1), 500 (DUL2), and 1,000 (DUL3) mg/kg in the basal diet, respectively. Results showed that DUL supplementation increased the final BW, average daily gain, and average daily feed intake of pigs (p < 0.05). Additionally, DUL2 decreased the feed-to-gain ratio of the pigs and increased the apparent digestibility of gross energy, dry matter, crude protein, ash, and calcium compared to CON group (p < 0.05). The contents of IgG and IgM in serum increased linearly with an increased inclusion level of DUL, whereas the serum IL-1β and TNF-α contents were linearly decreased with the increased DUL levels (p <0.05). Similarly, DUL addition linearly increased the activity of SOD, GSH-px, and CAT, but decreased the MDA contents in serum (p <0.05). Microbial analysis showed that the DUL supplementation had no effects on the diversity of fecal microbiota. While LEfSe analysis showed that Rikenellaceae_RC9_gut_group was enriched in DUL1 group, while the Enterobacterales were enriched in DUL3 group. Spearman correlation analysis identified a correlation between the abundance of Lactobacillus and Prevotellaceae_NK3B31_group and the functions of antioxidants and immune (p < 0.05). Collectively, current study demonstrated that 500 mg/kg DUL supplementation could increase growth performance and nutrients digestibility, as well as promote serum immune and antioxidant indices of growing-finishing pigs.