Whey protein improves exercise performance and biochemical profiles in trained mice

Abstract

Purpose: The objective of this study is to verify the beneficial effects of whey protein (WP) supplementation on health promotion and enhance exercise performance in an aerobic-exercise training protocol.

Methods: In total, 40 male Institute of Cancer Research mice (4 wk old) were divided into four groups (n = 10 per group): sedentary control with vehicle (SC) or WP supplementation (4.1 g·kg, SC + WP), and exercise training with vehicle (ET) or WP supplementation (4.1 g·kg, ET + WP). Animals in the ET and ET + WP groups underwent swimming endurance training for 6 wk, 5 d·wk. Exercise performance was evaluated by forelimb grip strength and exhaustive swimming time as well as by changes in body composition and biochemical parameters at the end of the experiment.

Results: ET significantly decreased final body and muscle weight and levels of albumin, total protein, blood urea nitrogen, creatinine, total cholesterol, and triacylglycerol. ET significantly increased grip strength; relative weight (%) of liver, heart, and brown adipose tissue (BAT); and levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase, creatine kinase, and total bilirubin. WP supplementation significantly decreased final body, muscle, liver, BAT, and kidney weight and relative weight (%) of muscle, liver, and BAT as well as levels of aspartate aminotransferase, lactate dehydrogenase, creatine kinase, and uric acid. In addition, WP supplementation slightly increased endurance time and significantly increased grip strength and levels of albumin and total protein.

Conclusion: WP supplementation improved exercise performance, body composition, and biochemical assessments in mice and may be an effective ergogenic aid in aerobic exercise training.

FIGURE 1

A, Protocol for 6-wk swimming ET. B, Effect of WP supplementation and 6-wk ET on body weight. Data are mean ± SEM. Different letters (a, b, and c) indicate significant difference at P < 0.05. Main-effect P values and interaction between WP and ET by two-way ANOVA are indicated.

FIGURE 2

Effect of WP supplementation and 6-wk ET on physical performance, including forelimb grip strength (A) and exhaustive swimming time (B). Data are mean ± SEM. Different letters (a, b, and c) indicate significant difference at P < 0.05. Main-effect P values and an interaction between WP and ET by two-way ANOVA are indicated.

FIGURE 3

Effect of WP supplementation and 6-wk ET on skeletal muscles: ventral view of animals (A) and histology of muscle tissues (B). Specimens were photographed by light microscopy (H&E staining, magnification: ×200; scale bar, 20 μm).

FIGURE 4

Effect of WP supplementation and 6-wk ET on morphology of liver (A), kidney (B), heart (C), and lung (D) tissues. Specimens were photographed by light microscopy (H&E staining, magnification: ×200; scale bar, 20 μm).