Low Protein Diet Improves Meat Quality and Modulates the Composition of Gut Microbiota in Finishing Pigs

Cui Zhu; Jingsen Yang; Qiwen Wu; Jingping Chen; Xuefen Yang; Li Wang; Zongyong Jiang

doi:10.3389/fvets.2022.843957

Low Protein Diet Improves Meat Quality and Modulates the Composition of Gut Microbiota in Finishing Pigs

Front Vet Sci. 2022 May 17:9:843957. doi: 10.3389/fvets.2022.843957. eCollection 2022.

Authors

Cui Zhu^{1

2}, Jingsen Yang^{1

2}, Qiwen Wu¹, Jingping Chen¹, Xuefen Yang¹, Li Wang¹, Zongyong Jiang¹

Affiliations

¹ Institute of Animal Science, Guangdong Academy of Agricultural Sciences, State Key Laboratory of Livestock and Poultry Breeding, Ministry of Agriculture Key Laboratory of Animal Nutrition and Feed Science in South China, Guangdong Provincial Key Laboratory of Animal Breeding and Nutrition, Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China.
² School of Life Science and Engineering, Foshan University, Foshan, China.

Abstract

This study investigated the effect of a low protein (LP) diet on growth performance, nitrogen emission, carcass traits, meat quality, and gut microbiota in finishing pigs. Fifty-four barrows (Duroc × Landrace × Yorkshire) were randomly assigned to three treatments with six replicates (pens) of three pigs each. The pigs were fed with either high protein (HP, 16% CP), medium protein (MP, 12% CP), and LP diets (10% CP), respectively. The LP diets did not influence the growth performance, but significantly decreased the plasma urea nitrogen contents and fecal nitrogen emission (P < 0.05). The LP diet significantly decreased the plasma contents of malondialdehyde (MDA) and increased the plasma glutathione (GSH) contents (P < 0.05). The LP diets significantly increased the backfat thickness at the first and last ribs, L^* (lightness) value of meat color, and muscle fiber density in the longissimus dorsi (P < 0.05). The messenger RNA (mRNA) expression of fatty acid synthetase (FAS), peroxisome proliferator-activated receptor-gamma (PPARγ), leptin, and acetyl-CoA carboxylase (ACC) was significantly downregulated, while that of carnitine palmitoyltransferase 1 (CPT1) and myosin heavy chain (MYHC) IIx in the longissimus Dorsi muscle was significantly upregulated by LP diets (P < 0.05). The 16S sequencing analysis showed that the abundance of unidentified Bacteria at the phylum level, and Halanaerobium and Butyricicoccusat at the genus level in the colonic digesta were significantly decreased by LP diet (P < 0.05). The LP diet significantly decreased the observed species of α-diversity in both ileal and colonic microbiota (P < 0.05). Spearman correlation analysis identified a significant positive correlation between the abundance of the ileal genera Streptococcus and L^* value at 24 and 48 h, and a significant negative correlation between unidentified_Ruminococcasceae in both ileum and colon with L^* value at 24 h (P < 0.05). Collectively, the LP diet supplemented with lysine, methionine, threonine, and tryptophan could reduce the fecal nitrogen emission without affecting growth performance and improve meat quality by regulating the antioxidant capacity and gene expression involved in fat metabolism as well as modulating the gut microbiota composition in finishing pigs.

Keywords: antioxidant capacity; finishing pig; gut microbiota; low protein diet; meat quality.