The objectives of this project were to investigate the effects of dietary lysine restriction on (1) the plasma concentrations of selected metabolites, free AAs, and three growth-related hormones, (2) the gene expression profile in longissimus dorsi muscle growing pigs. Twelve individually penned young barrows (Yorkshire × Landrace; 22.6 ± 2.04 kg) were randomly assigned to two dietary treatments (a lysine-deficient, LDD, and a lysineequate, LAD) diets, respectively. Pigs had ad libitum access to water and their respective diets for 8 weeks, and the ADG, ADFI, and G:F were determined. At the end of the trial, jugular vein blood was collected, and plasma was separated for the analysis of plasma parameters. Also, the longissimus dorsi muscle samples were collected from each pig for gene expression profile analysis. The ADG of LDD pigs was lower than that of LAD pigs, and so was the G:F since there was no difference in the ADFI between the two groups of pigs. The plasma concentrations of lysine, methionine, leucine, and tyrosine were lower, while that of β-alanine was higher, in the LDD pigs. The total plasma protein concentration was lower in the LDD pigs, whereas no differences were observed for the other metabolites, and the plasma concentrations of GF, insulin, and IGF-1 between the two groups. While gene expression profile results showed that sixty-nine genes were found differentially expressed (Benjamin-Hochberg corrected P-value < 0.05) in Diet I vs. Diet II pigs, of which 29 genes were down-regulated (Log₂ fold change (FC) < - 0.58) and 40 genes were up-regulated (Log₂ FC > 0.58). Furthermore, bioinformatic analyses revealed that the upregulation and downregulation of the DEGs may negatively affect the muscle protein turnover, structural development, and lipid metabolism of skeletal muscle. In conclusion, these results indicate that the lack of lysine including other two EAA as protein building block must be the primary reason for the compromised G:F ratio and ADG. The changes in the performance might be associated with some cell signaling and metabolic pathways suggested from the Bioinformatic results; however, may not involve the GH/IGF-1 axis.
| Identifer | oai:union.ndltd.org:MSSTATE/oai:scholarsjunction.msstate.edu:td-2732 |
| Date | 01 May 2020 |
| Creators | Hasan, Md Shamimul |
| Publisher | Scholars Junction |
| Source Sets | Mississippi State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
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