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The offspring of high parity sows face problems such as decreased growth performance, poor meat quality and even diseases in animal husbandry. Gama-aminobutyric acid (GABA) has been known to promote growth and suppress inflammation, but little is known about the mechanisms. The objective of this study was to estimate that whether dietary GABA supplementation has beneficial effects on growth performance, antioxidant indices, tissue morphology and the abundance of inflammatory signalling in the liver of growing-finishing pigs, and to explore whether the regulation of GABA on TLR4/NF-κB is mediated by GABA receptors in vitro. A total of 72 growing-finishing pigs from 8th parity sows were randomly allotted to 2 groups with 6 replicates per treatment to receive a corn–soybean basal diet or the basal diet supplemented 20 mg/kg GABA for 60 d. After the animal-trial period, the performance parameters were calculated, samples of serum and liver were collected for further analysis. Additionally, a lipopolysaccharide (LPS)-induced inflammatory model using HepG2 cells was established to explore the role of GABA on regulating hepatic inflammation.
The results indicated that GABA supplementation improves growth performances. The GABA had a positive effect on the feed conversion ratio. Dietary supplementation with GABA influenced liver morphology, increased activities of antioxidant enzymes and decreased the expression abundance of pro-inflammatory cytokines, including tumor necrosis factor-α (TNFα) and interleukin (IL)-1β, in the liver of growing-finishing pigs. In addition, GABA supplementation increased mRNA expressions of peroxisome proliferator-activated receptor γ (PPARγ) and GABA receptors (GABARs) and reduced the expression of toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) signaling. Additionally, an in vitro experiment demonstrated that GABA decreased the expressions of hepatic TLR4/NF-κB signaling via activating GABARs under LPS-stress.
In summary, liver injury may affect the growth performance of growing-finishing pigs by changing hepatic mitochondrial metabolism, the expression of pro-inflammatory cytokines and TLR4/NF-κB pathway and that GABA supplementation has a restorative effect by acting on GABARs.
Zhang S, Zhao J, Hu J, He H, Wei Y, Ji L, Ma X. Gama-aminobutyric acid (GABA) alleviates hepatic inflammation via GABA receptors/TLR4/NF-κB pathways in growing-finishing pigs generated by super-multiparous sows. Animal Nutrition. 2022; 9: 280-290. https://doi.org/10.1016/j.aninu.2022.02.001
