الفهرس 
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Abstract
The present study aimed to investigate the effect of immediate feeding after exercise bout on body mass index, hind limbs muscle mass, muscle glycogen content, fat tissue weight, plasma glucose, insulin level and insulin resistance either in obese or non-obese adult male albino rats versus delayed feeding by three hours after exercise.
Sixty adult male albino rats after exclusion of the dead, of equal distribution from the local strain, weighing from 65-75 gm and aging from 7-10 days, were selected at the beginning of this study. They were housed at room temperature with natural light/dark cycles in suitable cage. Rats were fed a standard diet of commercial rat chow and tap water and left to acclimatize to environment for two weeks prior to inclusion in the experiment.
Rats were randomized into two equal groups (30 rats for each). The first was exposed for induction of obesity by hypercaloric diet and the other completes the standard one. All rats were weighted and their nose to tail length was measured and body mass index was detected weekly. At the end of the 12th week of age there were a significant difference in body mass index between both groups (that exposed for induction of obesity and the control one). After that, rats started the exercise program for three months. They were not allowed to eat 1.5 h before the onset of training; the immediate group receives their meals immediately after exercise and the delayed one receive their meals three hours later. Then after receiving their meal, free access to food was allowed.
Experimental groups:
• Obese group (30 rats): Divided into three equal subgroups (10) rats for each groups as follows:
a- Obese non-exercised.
b- Obese exercised every other day and take their meal immediately after exercise.
c- c- Obese exercised every other day and take their meal three hours after exercise.
• Non obese (lean) group (30 rats): Divided into three equal subgroups (10) rats for each groups as follows:
a- Lean non exercised groups.
b- Lean exercised rats exercise every other day and receive their meal immediately after exercise.
c- Lean exercised rats exercise every other day and receive their meal three hours after exercise.
Exercise swimming program:-
At the beginning of the program, the aquatically native rats were given the chance to stay in water bath for a short time in few numbers. After becoming familiar with water rats were put in water bath in large numbers and were urged to swim actively all the time. Rats in exercise groups were exercised by swimming 1h/day for 12 weeks. The swimming exercise was performed in plastic barrel (50cm) diameter filled with water (50cm deep) maintained at 32-360C. Rats stop swimming one day before decapitation and were left fasting for 12hrs. before decapitation.
Samples of blood were taken from all animals at the beginning and at the end of experiment. Fasting blood samples were withdrawn through the Retro-orbital route using heparinized capillary tubes inserted in medial canthus medial to eye globe. The blood samples were delivered into centrifuge tubes to which anticoagulant were added. They were then centrifuged for 20 minutes and plasma was separated and stored as - 70 °C until used. These samples were examined for plasma glucose and plasma insulin. Insulin resistance was estimated by HOMA-IR formula.
Results:
After obesity induction there was a significant higher body mass index between the obese groups (ON,OI and OD) and their corresponding control groups (CN, CI and CD). Then after 12 weeks of training.
-Obese groups (ON, OI and OD) showed significant higher BMI and total fat tissue weight than their corresponding control groups (CN, CI and CD) respectively.
- Trained groups (CI and CD) and (OI and OD) showed significant lower BMI and fat weight than their corresponding non exercised groups CN and ON respectively.
- Immediate feeding groups (CI and OI) groups showed no significant difference in BMI with their corresponding delayed feeding groups (CD and OD) respectively.
- Immediate feeding groups (CI and OI) groups showed significant lower fat tissue weight with their corresponding delayed feeding groups (CD and OD) respectively.
Gastrocnemius muscle weight showed that.
-Obese groups (ON, OI and OD) showed significant lower gastrocnemius muscle weight with their corresponding control groups (CN, CI and CD) respectively.
- Trained groups (CI and CD) and (OI and OD) showed significant higher gastrocnemius muscle weight than their corresponding non exercised groups CN and ON respectively.
- Immediate feeding groups (CI and OI) groups showed significant higher gastrocnemius muscle mass with their corresponding delayed feeding groups (CD and OD) respectively.
Gastrocnemius muscle glycogen content showed that:
-Obese groups (ON, OI and OD) showed significant higher muscle glycogen content with their corresponding control groups (CN, CI and CD) respectively.
- Trained groups (CI and CD) and (OI and OD) showed significant higher gastrocnemius muscle glycogen content than their corresponding non exercised groups CN and ON respectively.
- Immediate feeding groups (CI and OI) groups showed significant higher gastrocnemius muscle glycogen content with their corresponding delayed feeding groups (CD and OD) respectively.
At the start of the training schedule there was a significant higher plasma glucose between the obese groups (ON,OI and OD) and their corresponding control groups (CN,CI and CD).
At the end of the exercise schedule there was:
- The ON group showed significant higher plasma glucose level than that of the corresponding CN group but with training the obese exercised groups (OI and OD) showed no significant difference with the corresponding control exercised (CI and CD) one.
- Trained groups (CI and CD) showed no significant difference in plasma glucose level with their corresponding non exercised groups (CN), however OI and OD groups showed significant difference with their corresponding ON group.
- Immediate feeding groups (CI and OI) groups showed no significant difference with their corresponding delayed feeding groups (CD and OD) respectively.
- Trained groups (CI and CD) and (OI and OD) groups showed significant lower plasma glucose than their pre-training values (PPCI and PPCD) and (PPOI and PPOD) groups respectively.
At the start of the training schedule there was a significant higher plasma insulin between the obese groups (ON,OI and OD) and their corresponding control groups (CN,CI and CD).
At the end of the exercise schedule there was:
-Obese groups (ON, OI and OD) showed significant higher plasma insulin level than their corresponding control groups (CN, CI and CD) respectively.
- Trained obese groups (OI and OD) showed significant lower plasma insulin with their corresponding non exercised groups ON.
- Immediate feeding groups (CI and OI) groups showed no significant difference in plasma insulin level with their corresponding delayed feeding groups (CD and OD) respectively.
- Trained groups (OI and OD) groups showed significant lower plasma insulin level with their corresponding pre-training values.
At the beginning of the training schedule there was a significant higher insulin resistance values between the obese groups (ON,OI and OD) and their corresponding control groups (CN,CI and CD).
-Obese groups (ON, OI and OD) showed significant higher insulin resistance with their corresponding control groups (CN, CI and CD) respectively.
- Trained groups (OI and OD) showed significant lower insulin resistance than their corresponding non exercised groups ON respectively, however within the control groups (CN, CI and CD) groups there was no significant difference in insulin resistance.
- Immediate feeding groups (CI and OI) groups showed no significant difference in insulin resistance with their corresponding delayed feeding groups (CD and OD) respectively.
- All trained groups (CI and CD) and (OI and OD) groups showed significant decrease in insulin resistance than their corresponding per-training values.
In conclusion:
Immediate feeding after the exercise bout produce greater increase in muscle bulk and muscle glycogen with decreased fat tissue weight in comparison with that of the corresponding delayed feeding. Either between obese and control groups.
The percentage of change in muscle mass is higher in the immediate group than the delayed group by 41.9% and 37.5% in the CI and OI respectively.
The percentage of change in muscle glycogen content is higher in the immediate group than the delayed group by 45.5%and 26.4%in the CI and OI respectively.
The percentage of difference in the abdominal fat weight is lower in the immediate group than the delayed group by 30.2% and 40% in the CI and OI respectively.
Recommendations
- Sport nutritionist should advise training subjects to receive their meals immediately after exercise.
- Future studies under different physiological conditions as by studying the effect of meal timing after exercise on different sex is recommended.
Limitations
- lipoprotein lipase activity estimation in gastrocnemius muscle was recommended. Because, it was suggested that its activity is higher in the immediate group than the delayed one and that its level is negatively correlated with fat tissue weight. However, lipoprotein lipase kites exportation was difficult and delayed. So that, its result couldn’t be respected.