Dr. Caroline Loos, postdoctoral scientist at the University of Kentucky focuses in her research program on optimizing protein nutrition in relation to muscle development. She recently has done a study to evaluate the effect of graded levels of high-quality protein intake on the activation of muscle protein synthetic pathways in mature horses.
This study provides evidence that the consumption of Cavalor VitAmino activates muscle protein synthetic pathways in horses, indicating it stimulates the muscle cells to make more protein. Cavalor VitAmino activates the muscle mTOR pathway in a dose-dependent manner, similar to the response to high quality protein intake observed in humans.
Cavalor VitAmino is blend of high quality, easily digestible protein sources, including soybean meal, alfalfa meal and potato protein. Potato protein is a unique protein source to the equine market and known to have a higher nutritional value compared to other plant protein sources.
In fact, it has an essential amino acid content similar to certain animal protein sources, including high levels of leucine, a strong activator of muscle protein synthetic pathways.
Because this ingredient is a purified protein source, it is highly digestible in the small intestine of the horse leading to rapid absorption and availability of key amino acids. Consumption of Cavalor VitAmino resulted in a rapid and significant increase in blood essential amino acid concentrations in all horses on this study.
"Activation of the mechanistic target of rapamycin (mTOR)-controlled anabolic signaling pathways in skeletal muscle of rodents and humans is responsive to the level of dietary protein supply, with maximal activation and rates of protein synthesis achieved with 0.2 to 0.4 g protein/kg body weight (BW). In horses, few data are available on the required level of dietary protein to maximize protein synthesis for maintenance and growth of skeletal muscle. To evaluate the effect of dietary protein level on muscle mTOR pathway activation, five mares received different amounts of a protein supplement that provided 0, 0.06, 0.125, 0.25, or 0.5 g of crude protein (CP)/kg BW per meal in a 5 × 5 Latin square design. On each sample day, horses were fasted overnight and were fed only their protein meal the following morning. A preprandial (0 min) and postprandial (90 min) blood sample was collected and a gluteus medius muscle sample was obtained 90 min after feeding the protein meal. Blood samples were analyzed for glucose, insulin, and amino acid concentrations. Activation of mTOR pathway components (mTOR and ribosomal protein S6 [rpS6]) in the muscle samples was measured by Western immunoblot analysis. Postprandial plasma glucose (P = 0.007) and insulin (P = 0.09) showed a quadratic increase, while total essential amino acid (P < 0.0001) concentrations increased linearly with the graded intake of the protein supplement. Activation of mTOR (P = 0.02) and its downstream target, rpS6 (P = 0.0008), increased quadratically and linearly in relation to the level of protein intake, respectively. Comparisons of individual doses showed no differences (P > 0.05) between the 0.25 and 0.5 g of protein intake for either mTOR or rpS6 activation, indicating that protein synthesis may have reached near maximal capacity around 0.25 g CP/kg BW. This is the first study to show that the activation of muscle protein synthetic pathways in horses is dose-dependent on the level of protein intake. Consumption of a moderate dose of high-quality protein resulted in near maximal muscle mTOR pathway activation in mature, sedentary horses."
Caroline M M Loos, Kyle R McLeod, Sophie C Stratton, David A van Doorn, Isabelle D Kalmar, Eric S Vanzant, Kristine L Urschel, Pathways regulating equine skeletal muscle protein synthesis respond in a dose-dependent manner to graded levels of protein intake, Journal of Animal Science, Volume 98, Issue 9, September 2020, skaa268, https://doi.org/10.1093/jas/skaa268