The objective of this study is to specify the effect of pressurized soy protein isolate (pSPI), upon the physical development, growth hormones and antioxidants functions of SD rats. The methodology depends on the selection of one hundred male SD rats, divided randomly into 5 groups. Each group consists of 20 rats. The groups will be defined as one blank control group, three groups with pSPI at low, medium and high doses and another control group with native soy protein isolates (nSPI). Low, medium and high doses are represented by 0.333 g/kg, 1.667 g/kg and 3.333 g/kg pSPI per weight, respectively. The native soy protein isolate is represented by 3.333 g/kg nSPI per weight. In every group, four animals will be taken out to collect the blood samples and analyze insulin like growth factor-I, growth hormone, thyroid stimulating hormone, thyroxine and triiodothyronin. The other SD rats will be subjected to feeding for 63 consecutive days. The body weight, the body length and food intake of each rat are measured. The total antioxidant capacity, superoxide dismutase (SOD), malondialdehyde and Glutathione Peroxidase in liver and serum of each rat will be analyzed. The results indicated that the groups with medium and high dose of pSPI result in an obvious increase in the body weight, body length and food utilization rate of SD rats. Also, pSPI has a great effect on the growth and antioxidants functions of SD rat.
Protein is the material basis of life. It is the basis for growth and development. It has a dual function, not only produce energy, but also, can provide raw materials for the construction of the body’s tissues, the body’s growth and development. Soybeans have been an important protein source in Asian countries and have been utilized in various forms [
One hundred healthy male SD rats were weaned, weighing 65 ± 10 g, divided randomly into 5 groups. Each group consists of 20 rats. The groups will be defined as blank control group, three groups with pSPI at low, medium and high doses (pSPI(1), pSPI(2) and pSPI(3)) and another control group with native soy protein isolates (nSPI). The recommended amount of SPI for human body is 20 g/d in adult weight 60 kg. It is equivalent to 0.333 g/kg per weight. pSPI high-dose group (pSPI(3)) is selected to be 10 times of the amount recommended by the human body and equal to 3.333 g/kg per weight per day. pSPI medium-dose group (pSPI(2)) is selected to be 5 times of the amount recommended by the human body and equal to 1.667 g/kg per weight per day. pSPI low-dose group (pSPI(1)) is selected to be one time of the amount recommended by the human body and equal to 0.333 g/kg per weight per day. For nSPI control group, the dose is selected to be the same as the pSPI (3) and equal to 3.333 g/kg per weight. Sample is given by adding it to the food. Blank control group is given a direct feed on a regular basis. pSPI with low, medium and high dose group and nSPI controls group are given according to the weekly average weight calculation. Feed content of the sample is calculated according to:
Four animals will be taken out to collect the blood samples and analyze insulin like growth factor I (IGF-I), triiodothyronin (T3), major of thyroid hormone in blood (T4), thyroid stimulating hormone (TSH) and growth hormone (GH). The blood samples will be taken in 14th day, 49th day, and 63th day. The other SD rats are subjected to feeding for 63 consecutive days. The body weight, the body length and food intake for each rat are measured twice a week. After killing the rats, the blood samples are collected and the separations of the serum will be done to determine the serum growth hormone, metabolism-related hormone (IGF-I, T3, T4, TSH and GH) content. Measuring the content of biochemical indicators will be done by taking the liver tissue and prepare liver tissue homogenates which are used to detect (T-AOC, SOD, MDA, GSH-Px).
SAS statistical software is used to compare mean values from five groups by the homogeneity test. The results are expressed as means ± standard deviation. Differences between mean values were determined by ANOVA. For all comparisons, differences with P < 0.05 were considered significant.
During the course of the experiment, all the animals are generally in a good condition, no animals have any significant adverse reactions and there is no any poisoning state or death.
The total time for the experiment is 63 days. The SD rats will be orally feed at different doses, with soy protein isolate treated with high pressure. The body weight of the SD rats will be trend every week and will be compared with the control group.
Group | Control | pSPI (1) | pSPI (2) | pSPI (3) | nSPI |
---|---|---|---|---|---|
D0 (weight) | 63.7 ± 9.8 | 65.5 ± 7.2 | 65.0 ± 8.8 | 63.4 ± 9.2 | 64.8 ± 8.2 |
D7 (weight) | 101.3 ± 6.9 | 103.3 ± 9.8 | 111.5 ± 13.6* | 113.6 ± 6.2* | 112.0 ± 12.6* |
D14 (weight) | 142.6 ± 12.6 | 150.8 ± 11.5 | 154.5 ± 14.3* | 159.5 ± 11.2* | 158.3 ± 14.1* |
D21 (weight) | 189.9 ± 10.4 | 195.8 ± 11.3 | 194.0 ± 12.9 | 203.6 ± 8.2 | 198.9 ± 13.8 |
D28 (weight) | 231.6 ± 9.7 | 238.0 ± 10.7 | 240.0 ± 13.1 | 244.5 ± 10.3 | 240.2 ± 8.2 |
D35 (weight) | 266.8 ± 13.6 | 273.2 ± 16.5 | 276.0 ± 18.8 | 280.9 ± 11.7 | 277.3 ± 10.4 |
D42 (weight) | 306.1 ± 14.6 | 312.9 ± 11.3 | 316.7 ± 10.3 | 320.6 ± 15.3 | 318.1 ± 19.3 |
D49 (weight) | 340.0 ± 14.5 | 347.7 ± 15.2 | 353.3 ± 18.3 | 355.5 ± 17.5 | 354.6 ± 13.1 |
D56 (weight) | 360.4 ± 16.8 | 369.9 ± 10.7 | 373.8 ± 19.6* | 382.0 ± 14.9* | 378.0 ± 15.1* |
D63 (weight) | 386.7 ± 18.9 | 397.8 ± 12.3 | 402.8 ± 18.7* | 407.7 ± 14.5* | 403.8 ± 15.7* |
Note: *Significantly different compared with the blank control group, P < 0.05.
that, the best IR is obtained in case of pSPI(3) for all measurements. The best IR is equals to 543% and occurs at the end of the experiment.
Food utilization rate for animal is the increasing in body weight by a number of grams due to ingestion of each 100 g feed. During the feeding period the food intake of SD rats is recorded weakly to calculate the food utilization rate. Every week the rats are weighed and record the actual amount of feed intake. The food utilization rate is calculated as:
Insulin-like growth factors I and II (IGFs) are proteins produced by the liver in response to growth hormone produced by the pituitary. IGFs are responsible for the growth and development of somatic tissues, such as skeletal muscle and bone [
Group | Control | pSPI (1) | pSPI (2) | pSPI (3) | nSPI |
---|---|---|---|---|---|
D0 (length) | 13.9 ± 0.6 | 14.3 ± 0.7 | 14.3 ± 0.7 | 14.1 ± 0.6 | 14.3 ± 0.7 |
D7 (length) | 16.0 ± 0.4 | 16.6 ± 0.8 | 16.7 ± 0.7 | 16.6 ± 0.5 | 16.4 ± 0.8 |
D14 (length) | 18.4 ± 0.5 | 18.6 ± 0.6 | 18.7 ± 0.6 | 18.8 ± 0.5 | 18.8 ± 0.6 |
D21 (length) | 20.3 ± 0.3 | 20.5 ± 0.5 | 20.7 ± 0.8 | 20.8 ± 0.6 | 20.8 ± 0.7 |
D28 (length) | 21.5 ± 0.3 | 21.8 ± 0.7 | 22.0 ± 0.7 | 22.1 ± 0.6 | 22.0 ± 0.5 |
D35 (length) | 22.8 ± 0.3 | 23.0 ± 0.4 | 23.2 ± 0.6 | 23.3 ± 0.5 | 23.3 ± 0.6 |
D42 (length) | 23.7 ± 0.4 | 24.0 ± 0.5 | 24.1 ± 0.5 | 24.2 ± 0.5 | 24.1 ± 0.7 |
D49 (length) | 24.3 ± 0.4 | 24.7 ± 0.5 | 24.8 ± 0.6* | 24.8 ± 05* | 24.8 ± 0.5* |
D56 (length) | 24.8 ± 0.5 | 25.2 ± 0.5 | 25.3 ± 0.5* | 25.3 ± 0.4* | 25.3 ± 0.5* |
D63 (length) | 25.1 ± 0.4 | 25.4 ± 0.4 | 25.5 ± 0.3* | 25.6 ± 0.4* | 25.5 ± 0.4* |
Note: *Significantly different compared with the blank control group, P < 0.05.
Group | Control | pSPI (1) | pSPI (2) | pSPI (3) | nSPI |
---|---|---|---|---|---|
1st week | 39.5 ± 10.6 | 42.4 ± 14.5 | 50.1 ± 6.0 | 55.1 ± 12.6* | 48.3 ± 6.8 |
2nd week | 32.2 ± 5.2 | 32.4 ± 5.7 | 33.9 ± 11.9 | 36.9 ± 10.0 | 34.2 ± 8.6 |
3rd week | 36.3 ± 8.2 | 32.7 ± 11.0 | 31.33 ± 6.1 | 32.7 ± 10.5 | 28.6 ± 7.6 |
4th week | 28.4 ± 6.7 | 30.0 ± 6.7 | 28.1 ± 5.1 | 28.7 ± 4.0 | 30.2 ± 10.6 |
5th week | 24.2 ± 4.8 | 24.5 ± 6.3 | 26.3 ± 5.7 | 26.6 ± 7.5 | 27.3 ± 7.5 |
6th week | 22.0 ± 3.2 | 23.5 ± 3.7 | 24.0 ± 4.2 | 25.3 ± 4.2 | 24.4 ± 5.0 |
7th week | 18.7 ± 2.5 | 21.2 ± 3.7 | 21.6 ± 3.1 | 23.8 ± 4.3* | 22.6 ± 5.3 |
8th week | 11.7 ± 3.9 | 11.7 ± 3.7 | 14.2 ± 5.1 | 17.0 ± 4.6* | 15.9 ± 4.9 |
9th week | 14.5 ± 5.2 | 14.8 ± 3.6 | 15.8 ± 3.0 | 16.8 ± 4.7 | 16.4 ± 3.0 |
Note: *Significantly different compared with the blank control group, P < 0.05.
Group | IGF-I (ng/ml) | ||
---|---|---|---|
D14 | D49 | D63 | |
Control | 50.7 ± 11.1 | 49.9 ± 5.6 | 55.4 ± 16.8 |
pSPI (1) | 51.1 ± 15.1 | 55.6 ± 14.5 | 57.3 ± 16.2 |
pSPI (2) | 53.0 ± 8.16 | 61.0 ± 11.0 | 59.6 ± 16.0 |
pSPI (3) | 57.9 ± 17.9 | 62.6 ± 12.7 | 69.7 ± 13.6 |
nSPI | 55.6 ± 11.1 | 57.5 ± 15.0 | 58.4 ± 10.1 |
Note: *Significantly different compared with the blank control group, P < 0.05.
Group | GH (ng/ml) | ||
---|---|---|---|
D14 | D49 | D63 | |
Control | 0.80 ± 0.18 | 0.65 ± 0.08 | 0.43 ± 0.10 |
pSPI (1) | 0.82 ± 0.22 | 0.66 ± 0.08 | 0.44 ± 0.08 |
pSPI (2) | 0.83 ± 0.07 | 0.71 ± 0.06 | 0.45 ± 0.07 |
pSPI (3) | 0.91 ± 0.09 | 0.72 ± 0.11 | 0.51 ± 0.07 |
nSPI | 0.83 ± 0.16 | 0.70 ± 0.05 | 0.45 ± 0.06 |
Note: *Significantly different compared with the blank control group, P < 0.05.
dicate that, the best value of IGF-I, is occurred in case of pSPI (3) group at D63. Also, as the dose increases, the IGF-I, value will be increases.
Group | T3 (ng/ml) | ||
---|---|---|---|
D14 | D49 | D63 | |
Control | 0.42 ± 0.09 | 0.22 ± 0.04 | 0.15 ± 0.04 |
pSPI (1) | 0.36 ± 0.06 | 0.28 ± 0.05 | 0.17 ± 0.03 |
pSPI (2) | 0.48 ± 0.14 | 0.24 ± 0.03 | 0.17 ± 0.03 |
pSPI (3) | 0.42 ± 0.08 | 0.29 ± 0.03 | 0.18 ± 0.02 |
nSPI | 0.36 ± 0.07 | 0.27 ± 0.04 | 0.18 ± 0.03 |
Note: *Significantly different compared with the blank control group, P < 0.05.
Group | T4 (ng/ml) | ||
---|---|---|---|
D14 | D49 | D63 | |
Control | 40.49 ± 3.93 | 42.07 ± 5.53 | 38.16 ± 3.00 |
pSPI (1) | 43.67 ± 7.64 | 42.45 ± 3.85 | 38.41 ± 4.12 |
pSPI (2) | 45.29 ± 8.92 | 43.65 ± 3.28 | 39.54 ± 3.10 |
pSPI (3) | 47.11 ± 8.42 | 43.81 ± 7.47 | 40.05 ± 6.27 |
nSPI | 44.32 ± 5.55 | 43.22 ± 8.45 | 38.49 ± 6.51 |
fect of soy protein isolates on T4 in the blood of SD rats which indicates that, the major of thyroid hormone in blood is T4 which is too higher than T3. Also, as the age increases the value of T4 decreases. The maximum value of T4 is occurred with pSPI (3) group and equals to (47.11 ng/ml) at D14. The minimum value of GH is occurred with control group and equals to (38.16 ng/ml) at D63.
The total antioxidant capacity (T-AOC) results due to the effect of soy protein isolates in the blood and liver of SD rats are shown in
The measured results of MDA level in the blood and liver of SD rats are shown in
Group | TSH (uIU/ml) | ||
---|---|---|---|
D14 | D49 | D63 | |
Control | 0.375 ± 0.020 | 0.427 ± 0.027 | 0.363 ± 0.035 |
pSPI (1) | 0.385 ± 0.062 | 0.373 ± 0.023 | 0.380 ± 0.048 |
pSPI (2) | 0.423 ± 0.034 | 0.385 ± 0.014 | 0.388 ± 0.067 |
pSPI (3) | 0.450 ± 0.029 | 0.453 ± 0.022 | 0.398 ± 0.049 |
nSPI | 0.393 ± 0.039 | 0.405 ± 0.017 | 0.383 ± 0.041 |
Group | T-AOC | |
---|---|---|
Liver (U/mg pro) | Blood (U/ml) | |
Control | 1.55 ± 0.35 | 7.03 ± 1.09 |
pSPI (1) | 1.80 ± 0.45 | 7.30 ± 0.96 |
pSPI (2) | 1.84 ± 0.42 | 7.74 ± 0.95* |
pSPI (3) | 3.41 ± 0.52* | 8.54 ± 1.03* |
nSPI | 2.01 ± 0.25* | 7.98 ± 0.82* |
Note: *Significantly different compared with the blank control group, P < 0.05.
Group | MDA | |
---|---|---|
Liver (nmol/mg pro) | Blood (nmol/ml) | |
Control | 0.63 ± 0.11 | 4.27 ± 0.74 |
pSPI (1) | 0.42 ± 0.08 | 3.90 ± 0.48 |
pSPI (2) | 0.41 ± 0.09 | 3.71 ± 0.44* |
pSPI (3) | 0.24 ± 0.08* | 3.48 ± 0.39* |
nSPI | 0.29 ± 0.07* | 3.71 ± 0.50* |
Note: *Significantly different compared with the blank control group, P < 0.05.
SOD is an important antioxidant enzyme in organisms and also a natural scavenger of superoxide anion. SOD
catalysis superoxide anion
of SOD in the blood and liver of SD rats are shown in
GSH-Px is an 80 kDa protein composed of four identical sub-units. Five isoforms of GSH-Px are well characterized in mammals and show tissue-specific distribution. Alteration of these enzyme levels is associated with diverse cancer types, including skin, kidney, intestine and breast cancer [
Group | SOD | |
---|---|---|
Liver (U/mg pro) | Blood (U/ml) | |
Control | 327.7 ± 15.9 | 102.1 ± 8.1 |
pSPI (1) | 337.6 ± 17.5 | 103.3 ± 6.8 |
pSPI (2) | 344.9 ± 20.6* | 109.6 ± 8.5* |
pSPI (3) | 353.5 ± 14.5* | 111.5 ± 7.7* |
nSPI | 335.3 ± 14.5* | 110.8 ± 9.5* |
Note: *Significantly different compared with the blank control group, P < 0.05.
Group | GSH-Px activities | |
---|---|---|
Liver (U/mg pro) | Blood (U/ml) | |
Control | 1037 ± 110 | 872 ± 69 |
pSPI (1) | 1088 ± 117 | 895 ± 59 |
pSPI (2) | 1121 ± 71 | 899 ± 75 |
pSPI (3) | 1196 ± 98* | 971 ± 85* |
nSPI | 1154 ± 94* | 954 ± 86* |
Note: *Significantly different compared with the blank control group, P < 0.05.
at pSPI (3) and nSPI group with high dose are significantly higher than the control group. The highest value is obtained in case of pSPI (3) group and equal to (1196 U/mg pro) with IR = 3.64% higher than nSPI. Also, the table shows that, the value of GSH-Px in liver is higher than the value of GSH-Px content in blood.
The effect of pressurized soy protein isolate (pSPI) upon the physical development, growth hormones and antioxidants functions of SD rats using animal experiment is studied. The results show that the groups with medium and high dose of pSPI result in an obvious increase in the body weight, body length and food utilization rate of rats. The highest values of food utilization occur in the first two weeks. The lowest values of the food utilization occur at the end of the experiment. In the pSPI high dose group and nSPI control group, the MDA content decreases and the activity of total antioxidant capacity (T-AOC) and glutathione peroxidase (GSH-PX) in liver is raised significantly (P < 0.05), compared with that of blank group. In the pSPI high, medium dose group and nSPI control group, the MDA content decreases and the activity of T-AOC and superoxide dismutase (SOD) in serum is raised significantly (P < 0.05), compared with that of blank group also, SOD in liver. Total antioxidant capacity (T-AOC) is an important indicator, which directly reflects the body activity and the overall level of non-enzymatic antioxidants. It is also a way to reflect the body’s antioxidant status. Studies in rats show that a certain amount of pSPI can enhance defense system in animals and maintain the body’s health in good state.
This work is supported by the Ministry of Science and Technology of China. The grant number is 2007DFA30820.