Dietary methionine deficiency stunts growth and increases fat deposition via suppression of fatty acids transportation and hepatic catabolism in Pekin ducks

Abstract

Background Although methionine (Met), the first-limiting dietary amino acid, has crucial roles in growth and regulation of lipid metabolism in ducks, mechanisms underlying are not well understood. Therefore, the objective was to use dietary Met deficiency to investigate the involvement of Met in lipid metabolism and fat accumulation of Pekin ducks. Methods A total of 150 male Pekin ducks (15-d-old, 558.5 ± 4.4 g) were allocated into 5 groups (6 replicates with 5 birds each) and fed corn and soybean meal-based diets containing 0.28%, 0.35%, 0.43%, 0.50%, and 0.58% Met, respectively, for 4 weeks. Met-deficient (Met-D, 0.28% Met) and Met-adequate (Met-A, 0.43% Met) groups were selected for subsequent molecular studies. Serum, liver, and abdominal fat samples were collected to assess the genes and proteins involved in lipid metabolism of Pekin ducks and hepatocytes were cultured in vivo for verification. Results Dietary Met deficiency caused growth depression and excess fat deposition that were ameliorated by feeding diets with adequate Met. Serum triglyceride and non-esterified fatty acid concentrations increased (P < 0.05), whereas serum concentrations of total cholesterol, low density lipoprotein cholesterol, total protein, and albumin decreased (P < 0.05) in Met-D ducks compared to those in Met-A ducks. Based on hepatic proteomics analyses, dietary Met deficiency suppressed expression of key proteins related to fatty acid transport, fatty acid oxidation, tricarboxylic acid cycle, glycolysis/gluconeogenesis, ketogenesis, and electron transport chain; selected key proteins had similar expression patterns verified by qRT-PCR and Western blotting, which indicated these processes were likely impaired. In vitro verification with hepatocyte models confirmed albumin expression was diminished by Met deficiency. Additionally, in abdominal fat, dietary Met deficiency increased adipocyte diameter and area (P < 0.05), and down-regulated (P < 0.05) of lipolytic genes and proteins, suggesting Met deficiency may suppress lipolysis in adipocyte. Conclusion Taken together, these data demonstrated that dietary Met deficiency in Pekin ducks resulted in stunted growth and excess fat deposition, which may be related to suppression of fatty acids transportation and hepatic catabolism.

Effect of supplementing lysins and methionine to low-protein diets on growth performance, hepatic antioxidant capacity, immune status, and glycolytic activity of tibetan sheep

“…Many studies have explored more effective use of Lys and Met in diets, not just to meet the nutritional needs but also as a health product. In Pekin ducks, dietary Met deficiency affected histological characteristics of the liver via suppression of fatty acids transportation and hepatic catabolism [ 20 ]. Meanwhile, the liver injury including swollen, blunt, turbid and lusterless were observed morphologically when fed Met-deficient diet in broilers, which might be related to oxidative stress and intestinal immunosuppression [ 21 ].…”

“…In the current experiment, high Met supplementation increased the activity of enzymes (glycogen and LDH) involved in the hepatic glycolysis in Tibetan sheep. Previously, expression of key proteins related to fatty acid transport, fatty acid oxidation and glycolysis/gluconeogenesis were suppressed when dietary Met deficiency, which were ameliorated by feeding diets with adequate Met [ 20 ]. Compared with low dietary Met, high Met supplement enhanced the mRNA levels of hepatic gluconeogenesis related genes such as phosphoenolpyruvate carboxykinase and glucose-6-phosphatase [ 42 ], which was effective in improving energy metabolisms in late pregnant ewes [ 43 ].…”

Proteomic and phosphoproteomic analysis reveal threonine deficiency increases hepatic lipid deposition in Pekin ducks via reducing STAT phosphorylation

“…In the previous report, dietary Thr deficiency increased the mRNA expression of hexokinase domain containing 1 ( HKDC1 ) and enolase 2 ( ENO2 ) participating in glycolysis ( Jiang et al., 2019b ). Dietary methionine deficiency reduced the expression of GAPDH and FBP in the liver of Pekin ducks ( Wu et al., 2022 ). In present experiment, dietary Thr deficiency increased MPC1 expression, and phosphorylation of HK, GAPDH and FBP.…”

Effects of the Dietary Replacement of Soybean Oil with Rubber Seed Oil on the Growth Performance, Carcass Trait, and Status of Lipid Metabolism in Pekin Ducks

“…The first strand cDNA was synthesized using equal amounts of total RNA and a Reverse Transcription cDNA Kit, and then stored at −80 • C for further analysis. The real-time PCR was performed in a CFX96™ Real-Time System (Bio-Rad, Hercules, CA, USA) using an SYBR Green Quantitative PCR kit, and the cycling conditions referred to previous reports [17]; the relative expression results of the target gene mRNA were calculated by the 2 −∆∆Ct method [18]. The primer sequences for target and reference genes are shown in Table 3.…”