Effects of glutamate on fatty acid profiles and lipid dynamics of fat tissues in Shaziling pig

Abstract The fat deposition and lipid composition directly influence meat quality and feed efficiency during pork production. Glutamate (GLU) is a major component of proteins and has been widely utilized in livestock production. However, the role of GLU in regulating lipid deposition and the lipo-nutritional quality of porcine fat remains unclear. This study aimed to investigate the effects of GLU on fatty acid composition and lipid profiles in subcutaneous fat (SF) and perirenal fat (PF) from Shaziling pigs. Forty-eight finishing pigs aged 150 days (31.56 ± 0.95 kg) were divided into the control (CON) group and the GLU-supplemented group (1% GLU), each consisting of 6 pens (4 pigs per pen). After 51 days, 6 pigs (1 pig/pen) from each group were slaughtered for analysis. Fatty acid analysis detected 46 species in SF and 40 in PF. In SF, 1% GLU significantly increased the content of C18:3n3 ( P < 0.05), which was accompanied by an increase in n3 PUFA deposition ( P < 0.05) and a decreased n6/n3 ratio ( P = 0.06). In PF, GLU supplementation reduced the levels of C18:1n9t, C24:1, C22:6n3, and others ( P < 0.05). The content of monounsaturated fatty acids (MUFAs) and n9 unsaturated fatty acids (UFAs) was significantly decreased in the GLU group ( P < 0.05). Similarly, GLU significantly reduced the n6/n3 PUFA ratio in PF ( P < 0.05). Lipidomics profiling identified 2264 unique lipids in fat tissues. GLU had minimal effects on lipid composition in SF but significantly reduced ceramides (Cer), phosphatidylserine (PS), and phosphatidylinositol (PIP) contents in PF ( P < 0.05) compared to the CON group. Additionally, GLU influenced the acyl chain saturation degree, fatty acyl chain length, and individual acyl chain composition in glycerophospholipid (GP) pools of PF. These results demonstrate the regulatory role of GLU on lipid dynamics in porcine fat and provide insights into regulating fat deposition and liponutritional quality in indigenous Chinese pig breeds.