Effects of Litsea cubeba essential oil on growth performance, blood antioxidation, immune function, apparent digestibility of nutrients, and fecal microflora of pigs

The purpose of this experiment was to investigate the effects of <i>Litsea cubeba</i> essential oil (LCO) on the growth performance, blood antioxidation, immune function, apparent digestibility of nutrients, and fecal microflora in fattening pigs. A total of 120 pigs were randomly assigned to five groups, with six replicate pens per treatment and four pigs per pen, and they were fed basal diet, chlortetracycline (CTC), and low-, medium-, and high-concentration LCO. The results of the study showed that compared with the control treatment and CTC addition treatment of the basic diet, the catalase level in the serum of the pigs treated with 500 mg/kg LCO in the diet of finishing pigs was significantly increased (<i>p</i> < 0.05). The apparent digestibility of crude protein, crude ash, and calcium in pigs with different levels of LCO was significantly increased compared with the control treatments fed the basal diet (<i>p</i> < 0.05). In addition, compared with the control treatment fed the basal diet and the treatment with <i>CTC</i>, the apparent digestibility of ether extract in pigs treated with medium-dose LCO was significantly increased (<i>p</i> < 0.05), and the apparent digestibility of pigs was significantly increased after the addition of low-dose LCO (<i>p</i> < 0.05). Among the genera, the percentage abundance of <i>SMB53</i> (<i>p <</i> 0.05) was decreased in the feces of the <i>CTC</i> group when compared to that in the medium-LCO group. At the same time, the relative abundance of <i>L7A_E11</i> was markedly decreased in the feces of the control and medium- and high-concentration LCO group than that in the <i>CTC</i> group (<i>p <</i> 0.05). In conclusion, adding the level of 250 mg/kg LCO in the diet of pig could improve the growth performance and blood physiological and biochemical indicators of pigs, improve the antioxidant level of body and the efficiency of digestion and absorption of nutrients, and show the potential to replace <i>CTC</i>.