To explore the effect and molecular mechanism of high F-value corn peptide on improving exercise capacity, so as to provide theoretical support for its development as a sports nutritional supplement.

Eighty SD rats were randomly divided into four groups: a control group and high F-value corn peptide with low-dose, medium-dose and high-dose groups. Each morning, the rats in low-dose, medium-dose and high-dose groups were orally administered with 0.1, 0.2 and 0.4 g/kg m_b of high F-value corn peptide respectively, and the rats in the control group were administered with the same volume of normal saline. All rats received one-hour swimming training without weight loading every day over a period of 8 weeks and also performed exercise in the first five days every week with two-day intervals. After the last treatment, weight-bearing exercise was carried out and the time to exhaustion was recorded. Blood lactate levels were determined as well. After being at rest for three days, the rats were sacrificed to harvest peripheral blood and skeletal muscle tissue. Subsequently, commercial test kits were used to measure malondialdehyde (MDA) concentration, and the activities of superoxide dismutase (SOD) activity and adenosine triphosphate (ATP) synthase and hydrolase in muscle. Meanwhile, the expression of the antioxidative stress regulator nuclear factor erythroid-2 related factor 2 (Nrf2), Kelch-like ECH-associated protein 1 (Keap1), the mitochondrial fusion protein mitofusin 2 (Mfn2) and the mitochondrial fission protein dynamin-related protein 1 (Drp1) were detected by Western blot analysis.

Compared with the control group, high F-value corn peptide significantly prolonged the exhaustive exercise time of mice (P < 0.05) in a dose-dependent manner, and dramatically reduced the level of blood lactic acid at 5 and 15 min after exhaustive exercise (P < 0.05). The level of blood lactic acid in the high-dose group was significantly lower than that in the low-dose group (P < 0.05). In addition, high F-value corn peptide dose-dependently significantly elevated the activities of ATP synthase and hydrolase in skeletal muscle of rats compared to the control group (P < 0.05). We also found that oral administration of high F-value corn peptide could increase SOD activity and reduce MDA production in skeletal muscle of experimental rats, increase the expression of Nrf2 in the nucleus and of Keap1 protein in the cytoplasm, significantly increase the expression of Mfn2, and significantly reduce the expression of Drp1.

High F-value corn peptide improves exercise capacity in experimental rats by improving the mitochondrial function of skeletal muscle.

To investigate the effect and mechanism of wheat peptide on improving cognitive capacity in chronic fatigue syndrome rats.

A total of 70 male SD rats were used in this study. From these, ten were randomly selected as a normal control group (N), and the other 60 rats were used to construct an animal model of chronic fatigue syndrome (CFS) by chronic restraint combined with exhaustive swimming in cold water. Then, they were randomly divided into a model control group (M), a low-dose wheat peptide group (M + L), a medium-dose wheat peptide group (M + M) and a highdose wheat peptide group (M + H). The rats in the M + L, M + M and M + H groups were orally administrated with wheat peptide at daily doses of 0.2, 0.4 and 0.8 g/(kg m_b·d) body mass for eight consecutive weeks, respectively. After this, water maze test was carried out to evaluate the cognitive capacity of experimental rats. After completion of the test, the rats were killed to collect serum for detecting the levels of tryptophan, nerve growth factor (NGF) and brain-derived neurotropic factor (BDNF), and Th1 and Th2 cytokines by enzyme-linked immunosorbent assay (ELISA), and the level of oxidative stress and the content of 5-hydroxy tryptamine (5-HT) in hippocampus tissues were measured as well.

Compared with the control group, the escape latency, and the serum levels of MDA, tryptophan, 5-HT and Th2 cytokines (interleakin (IL)-4 and IL-10) in the CFS model rats were significantly increased (P < 0.05). On the contrary, the number of times that the rats crossed the platform quadrant, the time spent in the platform quadrant, superoxide dismutase activity, and the levels of nerve growth factor and brain-derived neurotropic factor and Th1 cytokines (TNF-β and IFN-γ) all significantly decreased (P < 0.05). All these symptoms were significantly improved after eight weeks of oral administration of wheat peptide intervention.

Oral administration of wheat peptide can effectively improve cognitive function in CFS rats by activating the antioxidant system, regulating the secretion of neurocytokines and promoting cellular immune response resulting from the transformation from Th2-type cytokines to Th1-type cytokines.

To evaluate the antiobesity effect and underlying mechanism of Andrias davidianus peptide (ADP) supplementation combined with treadmill exercise.

A mouse model of obesity was established by feeding mice a high-fat diet (HFD), and the obese mice were randomly divided into four groups: model, treadmill exercise (Ex), ADP and ADP combined with treadmill exercise (ADP + Ex). The rats in the Ex group were subjected to a six-week treadmill exercise training. The rates in the ADP group were gavaged with ADP for six weeks. The rats in the ADP + Ex group were treated with ADP supplementation combined with treadmill exercise training. Normal Sprague Dawley (SD) rats were used as the control (CN) group. Body mass and food intake were recorded each week, and the serum levels of glucagon-like peptide-1 (GLP-1), neuropeptide Y (NPY), irisin, leptin, triglycerides (TG), total cholesterol (TC), low density lipoprotein (LDL) and high density lipoprotein (HDL) were investigated by enzyme-linked immunosorbent assay (ELISA). Western blot was used to detect the expression of appetite-regulated proteins (NPY and proopiomelanocortin (POMC)) and energy metabolism-related proteins.

Body mass, inguinal and epididymal fat accumulation, food intake, and serum TG, TC and LDL levels significantly decreased in the ADP + Ex group compared with the model group. In addition, ELISA results revealed that combination of ADP supplementation with treadmill exercise reduced the serum levels of NPY and leptin but increased the serum concentrations of GLP-1 and irisin in obese rats. Western blot analysis showed that ADP supplementation combined with treadmill exercise greatly up-regulated the expression of POMC and energy metabolism related proteins (irisin, phospho-adenosine monophosphate-activated protein kinase, peroxisome proliferator-activated receptor γ co-activated factor-1α, and fibronectin type Ⅲ domain containing protein 5), but down-regulated the expression of NPY.

The combination of ADP with aerobic exercise can effectively alleviate HFD-induced obesity, thereby providing a new promising strategy to alleviate HFD-induced obesity.