Effects of Dietary Supplementation of Alpha-Ketoglutarate in a Low-Protein Diet on Fatty Acid Composition and Lipid Metabolism Related Gene Expression in Muscles of Growing Pigs

Abstract

Simple SummaryAlpha-ketoglutarate (AKG) is a critical intermediate in the tricarboxylic acid cycle. AKG has been reported to participate in energy production, promote protein synthesis, and improve amino acid metabolism. However, whether AKG functionally participates in the regulation of fat metabolism remains unknown. The objective of this experiment was to evaluate the impact of dietary supplementation with AKG on lipid metabolism in a pig model. The present results suggest that AKG supplementation in a reduced-protein diet could increase the intramuscular fat (IMF) and monounsaturated fatty acid (MUFA) contents in the biceps femoris muscles of pigs. These effects could be linked to the altered lipid metabolism related gene mRNA expression, which promotes the absorption and deposition of fatty acids in the muscle tissues. The results of this study can provide better understanding of the mechanisms by which dietary AKG modulates muscle lipid metabolism in pigs, and this could help to improve pig feeding strategies and supply high-quality pork for humans.AbstractThe aim of the current study was to investigate whether dietary supplementation with alpha-ketoglutarate (AKG) in a reduced crude protein (CP) diet would affect fatty acid composition and lipid metabolism related gene expression in the muscles of growing pigs. A total of 27 Large White × Landrace growing pigs at 44 ± 1 d of age (11.96 ± 0.18 kg) were randomly allocated to three treatments (n = 9). Dietary treatments included: (1) normal protein diet with 20% crude protein (CP) (NP); (2) a low crude protein diet formulated to contain approximately 17% CP (LP); and (3) a low crude protein diet with 17% CP supplemented with 1% AKG at the expense of regular corn components (ALP). The experimental trial lasted 35 d. The results showed that compared with the NP and LP diets, supplementation with AKG in a low-protein diet increased the intramuscular fat (IMF), oleic acid (C18:1n-9), and monounsaturated fatty acid (MUFA) contents (p < 0.05), and tended to increase the percentage of palmitoleic acid (C16:1) and stearic acid (C18:0) (p < 0.10) in the biceps femoris and longissimus dorsi muscles of growing pigs. These effects may be associated with increased relative mRNA expression levels of fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), adipocyte determination and differentiation factor 1 (ADD1), fatty acid binding protein 4 (FABP4), and stearoyl-CoA desaturase (SCD) in skeletal muscle, indicating that AKG might be involved in the differential regulation of some key lipogenic genes in skeletal muscles of pigs.

From Acidifiers to Intestinal Health Enhancers: How Organic Acids Can Improve Growth Efficiency of Pigs

“…In weaning piglets challenged with E. coli LPS, dietary AKG supplementation improved both small intestine and liver morphology and function thus ameliorating the endotoxin-induced injury [107][108][109]. Moreover, the addition of AKG to a low-protein diet in pigs allowed to improve nitrogen, Ca and P metabolism and promote both protein and lipid metabolism in skeletal muscle (favoring intramuscular fat and monounsaturated fatty acids content), thus being a promising nutritional strategy to support pig productivity and supply high-quality pork [110][111][112].…”

Alterations of the Muscular Fatty Acid Composition and Serum Metabolome in Bama Xiang Mini-Pigs Exposed to Dietary Beta-Hydroxy Beta-Methyl Butyrate

“…Pork is the most consumed meat source for humans, and hence there has been a growing focus on pork quality [ 1 ]. An increasing body of literature has identified intramuscular fat (IMF) and the fatty acid composition of muscle tissues as important contributing factors to pork quality [ 2 , 3 , 4 , 5 ]. There is a close relationship between IMF and meat edible qualities such as juiciness, flavor, drip loss, and tenderness [ 6 ].…”

“…Specifically, excessive content of saturated fatty acid (SFA) and n6 polyunsaturated fatty acids (PUFA) together with increased ratios of SFA/PUFA and n6/n3 PUFA are associated with the development of cardiovascular and metabolic disorders in humans [ 10 , 11 ]. Nutritional modulation is an efficient strategy to alter the fatty acid profile and concentration of pigs’ muscles [ 3 , 12 ]. On this basis, the utilization of nutritional approaches to produce pork with an appropriate content of IMF and a balanced ratio of different kinds of fatty acid is an important objective pursuit of swine production.…”

Cholesterol Content, Fatty Acid Profile and Health Lipid Indices in the Egg Yolk of Eggs from Hens at the End of the Laying Cycle, Following Alpha-Ketoglutarate Supplementation

“…Glutamine is considered a non-essential amino acid and makes up about 50% of the free amino acid pool in the bloodstream and plays an important physiological role in general metabolism, including that of lipids and fatty acids [ 14 , 15 ]. Glutamine contributes to muscle repair, prevents protein catabolism, improves nitrogen retention and functions as an immunomodulatory molecule [ 16 , 17 , 18 ].…”