Animal Molecular Breeding, 2024, Vol.14, No.6, 380-387 http://animalscipublisher.com/index.php/amb 382 Figure 1 SAM Is derived from methionine in activated T cells (Adopted from Roy et al., 2020) Note: (A and B) 13C mass isotopomer distribution (MID) in SAM for Th1 and Th17 cells cultured with (A) [13C6]-glucose or (B) [13C3 15N]-serine for 6 h. Data represent the mean ± SEM for biological triplicates. (C) 13C MID in SAM and SAH for Th17 cells cultured with medium containing [13C5 15N]-methionine for 6 h. Data represent the mean ± SEM for biological triplicates. (D) Intracellular SAM and SAH levels in activated Teff cells following 6 h of culture in medium containing high (200 μM, Ctrl), low (3 μM, MR), or no (0 μM, -Met) methionine. Data represent the mean±SEM for biological triplicates. (E) Methylation index of Teff cells treated as in (D). Inset, SAM: SAH ratio for MR and-Met culture conditions (Adopted from Roy et al., 2020) 3.3 Role of transcription factors Transcription factors such as peroxisome proliferator-activated receptors (PPARs) and sterol regulatory element-binding proteins (SREBPs) are key regulators of gene expression in response to nutritional changes. PPARs are activated by fatty acids and play a significant role in lipid metabolism, influencing the expression of genes involved in fatty acid oxidation and storage. SREBPs, on the other hand, are crucial for cholesterol and lipid biosynthesis, and their activity is modulated by nutrient availability, particularly lipids (Cai et al., 2016). These transcription factors integrate nutritional signals to regulate metabolic pathways, ensuring that gene expression is aligned with the organism's nutritional status. 4 Impacts on Growth, Development, and Health 4.1 Regulation of genes influencing muscle growth and development Nutritional interventions significantly impact the regulation of genes associated with muscle growth and development in swine. For instance, dietary lysine restriction has been shown to alter the expression of genes in porcine skeletal muscle, affecting protein synthesis and muscle development through transcriptional regulators such as STAT3 and HNF1A (Wang et al., 2019). Similarly, dietary tryptophan influences muscle fiber type transformation, enhancing growth performance and increasing the proportion of fast muscle fibers in weaned piglets (He et al., 2024). Additionally, L-arginine supplementation promotes muscle gain by regulating lipid metabolism genes, favoring lipogenesis in muscle tissue (Tan et al., 2011). 4.2 Effects on immune system gene expression and disease resistance Nutritional interventions also modulate immune system gene expression, which can enhance disease resistance in swine. The balance of omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) in the diet affects genes related to immune response and inflammation, with an imbalance potentially increasing the risk of inflammatory diseases (Manaig et al., 2023). Furthermore, maternal energy restriction during gestation can alter the expression of immune-related genes in offspring, impacting their stress response and disease resistance (Sanglard et al., 2018). The plasticity of intestinal gene expression in response to nutritional interventions also highlights the potential for dietary strategies to modulate immune functions in piglets (Schokker et al., 2019). 4.3 Influence on genes associated with metabolic health and energy efficiency Nutritional interventions play a crucial role in regulating genes linked to metabolic health and energy efficiency in swine. For example, dietary protein intake affects the expression of genes involved in lipid metabolism in a
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