Muscle Metabolic Effects of Whole-Body Vibration in Yearling Horses

This study was designed to determine the effects of whole-body vibration (WBV) on select muscle metabolites in yearling horses on stall rest. Twenty yearling horses (17±2 months) were randomly divided into a split plot consisting of treatment (n=10) and control groups.Horses were assigned uniform stalls at the Texas A&M University Horse Center and given ad libitum access to water and trace mineral salt blocks. Horses were fed a diet for 100% DE and 110% protein, calcium, and phosphorus of the NRC recommendations using coastal grass hay and pelleted concentrate.

The treatment group completed WBV on a theraplate at 50 Hz for 30 minutes 5 days per week for 120 days. Serum was collected via jugular venipuncture in lithium heparin tubes on days 0, 30, 60, and 120 before a 30-minute turnout, and after turnout (control group) or vibration (treatment group). A single blood draw was collected on Day 0 as a baseline value to serve as a covariant. Samples were analyzed by Texas A&M University VMTH Clinical Pathology Lab for blood urea nitrogen, aspartate aminotransferase, gamma-glutamyltransferase, creatine kinase, and lactic acid within 24 hours of collection. Statistical analysis was completed using the PROC MIXED procedure of SAS 9.4, and significance was set to P≤0.05.

AST showed significant (P<0.05) reduction across all collections from an average of 301.27± 11.42 U/L before treatment to 287.73± 11.42 U/L post-treatment in control horses. GGT values for both groups showed a significant (P<0.05) decline between collections with the control group having a greater reduction. CK values had a significant (P<0.05) treatment-day interaction with the control group value decreasing and the treatment group value increasing.

Effect of vibration treatment in select blood metabolites: Means across all collections
Response Variable	Control	Vibration	Standard Error	P Value
BUN	13.96 mg/dl	14.11mg/dl	0.35	0.76
AST	294.5 U/L	303.13 U/L	11.23	0.59
GGT	21.2 U/L	21.31U/L	0.43	0.86
CK	187.94 U/L	211.08 U/L	9.59	0.1
LA	8.6 mg/dl	8.57 mg/dl	0.28	0.95

Elevated CK and AST values are indicative of muscle degradation; LA presence in blood is an indicator of anaerobic conditions during high intensity physical exertion. GGT is a biomarker used to exclude liver disease as a reason for elevated CK. WBV of young horses on stall rest does not provide significant sustained muscular benefits. Further studies using uniform muscle biopsies and hourly blood collections post-vibration are recommended for further understanding of the potential therapeutic applications of WBV.