Date of Award
8-2025
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Animal and Veterinary Sciences
Committee Chair/Advisor
Dr. Susan Duckett
Committee Member
Dr. William Bridges
Committee Member
Dr. Elliot Jesch
Abstract
Background
Satellite cells (SCs) are myogenic precursor cells that play a crucial role in muscle growth, and their activity can be influenced by nutrient supplementation. Muscle growth can also be stimulated using growth-promoting hormones; however, there are no approved growth hormones for use in sheep in the United States (Qaid & Abdoun, 2022). This limitation highlights a need to identify alternative compounds that would serve as nutrient supplements to enhance muscle growth and thereby improve meat production. Amino acid derivatives such as guanidinoacetic acid (GAA) and 5-hydroxytryptophan (5-HTP), along with the polyphenol quercetin, are naturally derived compounds that have shown to positively influence muscle growth (Chandran et al., 2012; Michiels et al., 2012; Wang et al., 2022). It is therefore important to investigate how these compounds may contribute to skeletal muscle growth in sheep.
Methods
Satellite cells were cultured in a Corning 24-well plate (45,000/well). The media was supplemented with different levels (0, 12.5, 25, and 50 μmol/L) of 5-HTP, GAA, or quercetin. Cells were counted after day 4 for proliferation and differentiation. For the in vivo study, 15 lambs were used (33 kg + 6 kg BW) with five lambs per group assigned to one of the treatments: control, GAA, or 5-HTP. Lambs were individually fed for 28 days, and supplements were administered at a dose of 2.5 mg/kg body weight via the sublingual route before feeding. At the end of the study, a muscle biopsy was carried out from the longissimus muscle at the 12th/13th rib, and real-time ultrasound measurements of ribeye area (REA) were recorded. The muscle samples were subsequently processed for mRNA sequencing to assess gene expression profiles.
Results
5-HTP (25 μmol/L) increased satellite cell number (P< 0.05), and 5-HTP (12.5 and 25 μmol/L) increased proliferation of SC (P< 0.05). There was no effect of 5-HTP on SC differentiation (P>0.05). Quercetin (12.5 and 25 μmol/L) also increased SC proliferation when compared with 0 μmol/L (P< 0.05), with no effect on SC differentiation (P>0.05). GAA altered SC differentiation in a dose-dependent manner, with 12.5 and 25 μmol/L differing from 0 μmol/L (P < 0.05), but showed no effect on SC proliferation (P>0.05). For lamb characteristics, GAA or 5-HTP did not influence (P>0.05) average daily gain, dry matter intake, or ribeye area compared to the control. miRNA qPCR showed that GAA nor 5-HTP did not alter miR-133a-3p and miR-133a-5p (P>0.05) expression compared with the control. mRNA sequencing showed that GAA supplementation altered gene expression (Padj < 0.05) compared to the control or 5-HTP. However, 5-HTP did not affect (P>0.05) gene expression compared to the control.
Conclusion
These data suggest that nutrient supplementation could influence satellite proliferation and differentiation in vitro, which could enhance muscle mass accretion. Short-term supplementation of GAA or 5-HTP to finishing lambs did not alter growth performance, carcass REA or miRNA expression; however, GAA supplementation did alter gene expression of four genes that are involved in muscle growth.
Recommended Citation
Iheanacho, Gabriella C., "Effect of Amino Acid Derivatives and Polyphenol Supplementation on Skeletal Muscle Growth In-vitro and In-vivo" (2025). All Theses. 4563.
https://open.clemson.edu/all_theses/4563