Effect of Dietary Inulin Supplementation on Growth Performance, Carcass Traits, and Meat Quality in Growing–Finishing Pigs

SIMPLE SUMMARY: Dietary fiber has attracted considerable research interest worldwide. Inulin is a critical soluble dietary fiber. This study investigated the effects of dietary inulin supplementation on the growth performance and meat quality in pigs, which provided novel insights into the application of inulin for the livestock industry. ABSTRACT: Inulin is one of the commercially feasible dietary fibers that has been implicated in regulating the gut health and metabolism of animals. This experiment was conducted to investigate the effect of dietary inulin supplementation on growth performance and meat quality in growing–finishing pigs. Thirty-six Duroc × Landrace × Yorkshire White growing barrows (22.0 ± 1.0 kg) were randomly allocated to two dietary treatments consisting of a basal control diet (CON) or basal diet supplemented with 0.5% inulin (INU). Results showed that inulin supplementation tended to increase the average daily gain (ADG) at the fattening stage (0.05 < p < 0.10). Inulin significantly increased the dressing percentage (p < 0.05) and tended to increase the loin-eye area. The serum concentrations of insulin and IGF-I were significantly higher (p < 0.05) in the INU group than in the CON group. Moreover, inulin supplementation significantly elevated the expression level of myosin heavy chain II b (MyHC IIb) in the longissimus dorsi (p < 0.05). Inulin significantly upregulated the expression of mammalian rapamycin target protein (mTOR) but decreased (p < 0.05) the expression level of muscle-specific ubiquitin ligase MuRF-1. These results show the beneficial effect of inulin supplementation on the growth performance and carcass traits in growing–finishing pigs, and will also facilitate the application of inulin in swine production.