Effects of glucose ingestion at different frequencies on glycogen recovery in mice during the early hours post exercise

Background When a high-carbohydrate diet is ingested, whether as small frequent snacks or as large meals, there is no difference between the two with respect to post-exercise glycogen storage for a period of 24 h. However, the effect of carbohydrate intake frequency on glycogen recovery a few hours after exercise is not clear. Athletes need to recover glycogen quickly after physical exercise as they sometimes exercise multiple times a day. The aim of this study was to determine the effect of carbohydrate intake at different frequencies on glycogen recovery during the first few hours after exercise. Methods After 120 min of fasting, 6-week-old male ICR mice were subjected to treadmill running exercise (20 m/min for 60 min) to decrease the levels of muscle and liver glycogen. Mice were then given glucose as a bolus (1.2 mg/g of body weight [BW], immediately after exercise) or as a pulse (1.2 mg/g of BW, every 15 min × 4 times). Following this, the blood, tissue, and exhaled gas samples were collected. Results In the bolus group, blood glucose concentration was significantly lower and plasma insulin concentration was significantly higher than those in the pulse group (p < 0.05). The plantaris muscle glycogen concentration in the bolus group was 25.3% higher than that in the pulse group at 60 min after glucose ingestion (p < 0.05). Liver glycogen concentration in the pulse group was significantly higher than that in the bolus group at 120 min after glucose ingestion (p < 0.05). Conclusions The present study showed that ingesting a large amount of glucose immediately after exercise increased insulin secretion and enhanced muscle glycogen recovery, whereas frequent and small amounts of glucose intake was shown to enhance liver glycogen recovery.

Effect of the beta-adrenergic blockade on intestinal lactate production and glycogen concentration in dogs infused with hexoses

Objectives To investigate effect of beta adrenergic blockade on intestinal lactate production and glycogen concentration in dogs infused with hexoses. Methods Experiments were carried out on 35 fasted male anaesthetized dogs weighing between 9 and 16 kg. The animals were divided into 7 (5 dogs per group) groups. Group I dogs served as control and infused with normal saline, groups II-IV were intravenously infused with glucose (1.1 mg/kg/min), fructose (1.1 mg/kg/min) and galactose (1.1 mg/kg/min) respectively while groups V-VII animals were pretreated with propranolol (0.5 mg/kg) and were infused with glucose, fructose or galactose respectively. A vein draining the proximal segment of the jejunum was cannulated along with right and left femoral arteries and veins. Glucose uptake was calculated as the product of jejunal blood flow and the difference between arterial and venous glucose levels (A-V glucose), part of the jejunum tissue was homogenized for estimation of glycogen concentration, and plasma lactate was assayed using lactate colorimetric kit. Results The result showed significant increase in venous lactate production in response to glucose (78.30 ± 4.57 mg/dl), fructose (60.72 ± 1.82 mg/dl) and galactose (71.70 ± 1.30 mg/dl) when compared with the control group (51.75 ± 1.32 mg/dl) at (p<0.05) with no significant difference in animals pretreated with propranolol. There was no significant difference in glycogen concentration (p>0.05) in animals infused with hexoses only compared with propanolol pretreated group. Conclusions Results suggests that one of the possible fates of the enormous amount of glucose taken up by the intestine is conversion to lactate and not glycogen and β-adrenergic receptor does not affect it.

BIOCHEMICAL AND HISTOPATHOLOGICAL STUDIES OF NEW TAPEWORM MOGHEIA JADHAVEIA IN MILVUS MIGRANS FROM AUSA REGION

The objective of the present study was biochemical analysis and histopathological relation between the new cestode Mogheia jadhaveia and host Milvus migrans. Bio-molecules such as protein, carbohydrates and lipids are determined in parasite and infected host. Result after comparison between cestode parasite and host intestine, protein and glycogen concentration is lower in Mogheia jadhaveia sp. than host intestine. Lipid content is more in parasite than host intestine. Histopathological relation is good maintain by parasite.

Temperature, but not excess of glycogen, regulates “in vitro” AMPK activity in muscle samples of steer carcasses

Postmortem muscle temperature affects the rate of pH decline in a linear manner from 37.5°C to 0–2°C. The pH decline is correlated with the enzymatic degradation of glycogen to lactate and this process includes the metabolic coupling between glycogenolysis and glycolysis, and that are strongly upregulated by the AMPK. In this study, we used 12 samples previously characterized by have different muscle glycogen concentration, lactate and AMPK activity, selected from 38 steers that produced high final pH (>5.9) and normal final pH (<5.8) carcasses at 24 h postmortem. Moreover, we evaluated changes in the AMPK activity in samples from both categories incubated at 37, 25, 17 and 5°C and supplemented with exogenous glycogen. Finally, we analysed if there were structural differences between polymers from both categories. Our results showed that “in vitro” enzymatic AMPK activity evaluated at both 0.5 or 24 h was greater in samples from normal then high pH categories (p <0.01), and in all temperature of incubation analysed (17, 25 and 37°C). For other hand, a greater AMPK activity were obtained in samples incubated at 17 that 25 or 37°C, in normal carcasses at both 0.5 or 24 h (p < 0.01), as also in samples from carcasses categorized as high pH, but at 24 h (p < 0.05). Interestingly, AMPK activity was totally abolished at 5°C, independent of final pH category of carcasses, and was confirmed that the incubation temperature at which the maximum activity was obtained (p < 0.01), at least in carcasses with a normal pH is at 17°C. The enzymatic AMPK activity did not change in relation to excess glycogen (p > 0.05) and we did not detect structural differences in the polymers present in samples from both categories (p > 0.05), suggesting that postmortem AMPK activity may be highly sensitive to temperature and not to in vitro changes in glycogen concentration (p > 0.05). Our results allow concluding that normal concentrations of muscle glycogen immediately at the time of slaughter (0.5 h) and an adequate cooling managing of carcasses are relevant to let an efficient glycogenolytic/glycolytic flow required for lactate accumulation and pH decline, through the postmortem AMPK signalling pathway.

Temperature, but not excess of glycogen, regulate post-mortem AMPK activity in muscle of steer carcasses

Post-mortem muscle temperature affects the rate of decline in pH in a linear manner from 37.5 °C down near 0 °C, and this pH decline is correlated with the enzymatic degradation of glycogen to lactate. This transformation occurs in an anaerobic context that includes the metabolic splice between glycogenolysis and glycolysis; and both processes are strongly upregulated by AMPK enzyme. In this study we reported changes (0.5 h and 24 h post-mortem) in muscle glycogen concentration, lactate and AMPK activity from 12 samples of Longissimus dorsi from 38 steers that produced high pH (>5.9) and normal pH (<5.8) carcasses at 24 h post-mortem. Moreover, we evaluated changes in AMPK activity in samples from both categories incubated at 37, 25, 17 and 5 °C and supplemented with exogenous glycogen. Finally, we analysed if there were structural differences between polymers from both categories. Our analyses show that enzymatic AMPK activity was significantly higher at 17 °C than at 37 °C or 25 °C (p<0.0001 and p<0.05 in samples from normal and high pH categories, respectively), and was near zero at 5 °C. On the other hand, AMPK activity did not change in relation with excess glycogen and we did not detect structural differences in the polymers present in samples from both categories. We concluded that post-mortem AMPK activity level is highly sensitive to temperature and not at in vitro changes in glycogen concentration. Their results suggest that that normal levels of pre-mortem muscle glycogen and an adequate cooling managing of carcasses are relevant to let an efficient glycogenolytic/glycolytic flow required for lactate accumulation and pH decline, trough of post-mortem AMPK signalling pathway.

Effects of pre-slaughter ascorbic acid administration on some physiological stress response and meat quality traits of lambs and kids subjected to road transport

The present study determined the effects of pre-slaughter ascorbic acid administration on some physiological indicators and meat quality traits of road transport-stressed lambs and kids. Eighteen lambs and 18 kids were divided into the following three groups: no transportation (T0), 3-h transportation (T3), and ascorbid acid administered at 125 mg/kg before 3-h transportation (T3+C). The liveweight loss and rectal temperature were similar, while there were significant differences among groups for some biochemical parameters in both lambs and kids. Glucose concentrations significantly increased after transportation in lambs (P = 0.005) and kids (P &lt; 0.001). Ascorbic acid had significant effects on serum glucose of lambs. T3 lambs had higher glucose concentrations than did T0 lambs (P &lt; 0.001), while T0 and T3+C lambs were found to have similar concentrations. Oxidative status in lambs and kids, as determined by serum malondialdehyde concentration, did not differ among groups. However, some meat quality traits were negatively influenced by transportation. T3 lambs had a significantly lower muscle glycogen concentration than did T0 and T3+C lambs (P = 0.018), while ultimate pH was similar among groups. Muscle glycogen concentration was significantly lower (P = 0.008) and ultimate pH was higher in T3 and T3+C kids (P = 0.028). T3 and T3+C groups had darker meat (L*) than did T0 groups both in lambs and kids, whereas a*, cooking loss and water-holding capacity were similar among groups. The effect of ascorbic acid on meat toughness was significant and shear force value in T0 lambs was lower than that in T3 lambs (P = 0.009), while T0 and T3+C lambs were found to have similar shear force values. Overall, the administration of ascorbic acid to lambs before transportation could partly reduce the adverse effects of road transportation stress, whereas its effects on kids were found to be insignificant.