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1.
Plasma lipid concentrations, lipoprotein composition, and glucose dynamics were measured and compared between mares fed diets containing added water, corn oil (CO), refined rice bran oil (RR), or crude rice bran oil (CR) to test the hypothesis that rice bran oil lowers plasma lipid concentrations, alters lipoprotein composition, and improves insulin sensitivity in mares. Eight healthy adult mares received a basal diet fed at 1.5 times the DE requirement for maintenance and each of the four treatments according to a repeated 4 x 4 Latin square design consisting of four 5-wk feeding periods. Blood samples were collected for lipid analysis after mares were deprived of feed overnight at 0 and 5 wk. Glucose dynamics were assessed at 0 and 4 wk in fed mares by combined intravenous glucose-insulin tolerance tests. Plasma glucose and insulin concentrations were measured, and estimated values of insulin sensitivity (SI), glucose effectiveness, and net insulin response were obtained using the minimal model. Mean BW increased (P = 0.014) by 29 kg (range = 10 to 50 kg) over 5 wk. Mean plasma concentrations of NEFA, triglyceride (TG), and very low-density lipoprotein (VLDL) decreased (P < 0.001) by 55, 30, and 39%, respectively, and plasma high-density lipoprotein and total cholesterol (TC) concentrations increased (P < 0.001) by 15 and 12%, respectively, over 5 wk. Changes in plasma NEFA (r = 0.58; P < 0.001) and TC (r = 0.44; P = 0.013) concentrations were positively correlated with weight gain over 5 wk. Lipid components of VLDL decreased (P < 0.001) in abundance over 5 wk, whereas the relative protein content of VLDL increased by 39% (P < 0.001). Addition of oil to the basal diet instead of water lowered plasma NEFA and TG concentrations further (P = 0.002 and 0.020, respectively) and increased plasma TC concentrations by a greater magnitude (P = 0.072). However, only plasma TG concentrations and VLDL free cholesterol content were affected (P = 0.024 and 0.009, respectively) by the type of oil added to the diet. Mean plasma TG concentration decreased by 14.2 mg/dL over 5 wk in the CR group, which was a larger (P < 0.05) decrease than the one (-5.3 mg/dL) detected in mares that received water. Consumption of experimental diets lowered S(I), but glucose dynamics were not affected by oil supplementation. Addition of oil to the diet altered blood lipid concentrations, and supplementation with CR instead of water specifically affected plasma TG concentrations and VLDL free cholesterol content.  相似文献   

2.
In this study 0 or 4 g of l ‐carnitine was supplemented for 7 days in a cross‐over design of six healthy ponies to modulate glucose metabolism and leptin production. At the end of each period, serial blood samples were taken to measure glucose and insulin response, leptin, triglyceride (TG), non‐esterified fatty acids (NEFA) and creatine phosphokinase. l ‐carnitine supplementation was associated with a decrease in postprandial plasma glucose and insulin concentration, indicating an enhanced glucose tolerance. In contrast, postprandial plasma leptin concentration was increased when l ‐carnitine was supplemented. Yet, this increase in leptin concentration was not preceded by an increase in insulin concentration, suggesting that other factors apart from plasma insulin concentration could influence plasma leptin concentration. Although NEFA and TG were not significantly influenced by l ‐carnitine supplementation under these experimental conditions, further research must clarify whether net TG synthesis might be responsible for this increase in leptin.  相似文献   

3.
An ovine-specific RIA, shown to be reliable for bovine leptin determination, was used to study the effects of breed, body fatness, feeding level, and meal intake on plasma leptin level in adult cattle. Eighteen fat Charolais, fat Holstein, and lean Holstein adult cows were either well-fed (130% of maintenance energy requirements [MER]) or underfed (60% of MER) for 3 wk. The breed tended to have a small effect on plasma leptin level, which was decreased by 70% (P < 0.05) in lean compared to fat Holstein cows. A strong curvilinear relationship was found between mean adipocyte volume and plasma leptin concentrations in well-fed (r = +0.95) and underfed (r = +0.91) cows. Underfeeding caused a significant decrease in plasma leptin levels from 8.0+/-3.1 to 6.1+/-2.3 ng/mL (P < 0.01). Nine adult Holstein cows initially fed at 130% of MER (control) were underfed to 21% of MER for 7 d, and five of them were refed to 237% of MER for 21 d. Plasma leptin measured 1 h before meal distribution was decreased from 5.9+/-0.4 to 3.8+/-0.2 ng/mL (P < 0.01) by underfeeding and increased to reach 8.8+/-1.0 ng/mL (P < 0.01) after refeeding. It was positively related to plasma glucose (r = +0.52, P < 0.01) and negatively related to plasma NEFA (r = -0.67, P < 0.001). Plasma leptin measured 4 h after meal distribution was positively related to feeding level and to plasma 3-OH-butyrate (r = +0.61, P < 0.005) and negatively related to plasma NEFA (r = -0.56, P < 0.01). Differences between pre- and postprandial leptin concentrations showed a decrease after meal intake in control and well-fed cows (-7 and -19%, P < 0.01, respectively) and an increase in underfed cows (+12%, P < 0.01). Leptin response to meal intake was positively related to glucose response (r = +0.66, P < 0.001) and negatively related to 3-OH-butyrate response (r = -0.78, P < 0.001). By using the "multispecies" commercial RIA, leptin concentrations were lower and we observed similar physiological responses, although less related to other hormones or metabolites. These data provide evidence, first, that a specific RIA for ruminant leptin determination is necessary to better understand leptin regulation, and second, that plasma leptin is strongly related to adipose cell size and positively related to feeding level in adult cattle, and that an effect of meal intake could be mediated by glucose and(or) ketone bodies.  相似文献   

4.
The objective of this experiment was to investigate the effect of fat supplementation during the transition period on pre and postpartum body weight (BW), body condition score (BCS), non‐esterified fatty acids (NEFA), glucose and leptin concentrations in Holstein cows. Holstein cows (n = 15) received a low fat diet (LF; 1.61 Mcal net energy for lactation (NEL)/kg of dry matter [DM]), moderate fat diet (MF; 1.68 Mcal NEL/kg DM) or a high fat diet (HF; 1.74 Mcal NEL/kg DM) for 4 weeks prior to calving. All cows were fed similar lactation diets ad libitum (1.74 Mcal NEL/kg DM) for 30 days after calving. Increasing diet energy density during transition period had no effect on prepartum DMI, BCS, BW, glucose and NEFA concentrations (P > 0.05); but leptin concentrations and energy balance (EB) were affected by treatments (P < 0.05). Animals fed HF had less plasma leptin prepartum. After parturition, BW, milk production, milk fat, protein, urea nitrogen and plasma glucose concentrations were affected by prepartum diets (P < 0.05). Fat supplementation prepartum did not affect postpartum NEFA. In conclusion, prepartum fat supplementation decreased leptin concentration prepartum.  相似文献   

5.
A study was undertaken to investigate the changes of plasma non-esterified fatty acids (NEFA), glucose and alpha-amino nitrogen and their relationship with age, body weight (BW) and plasma growth hormone (GH) in growing buffaloes. For the purpose, six growing female Murrah buffalo calves of 6-8 months of age were selected on the basis of their BW and fed according to Kearl standard (Nutrient Requirements of Ruminants in Developing Countries, International Feedstuffs Institute, Utah State University, Utah, USA, 1982, p. 89) for growing buffaloes (target growth rate 500 g/day) to meet energy and protein requirement of the animals. Blood samples collected at fortnight intervals for 1 year were analysed for plasma NEFA, glucose, alpha-amino nitrogen and GH. The animals were also weighed at fortnight intervals. Plasma NEFA and glucose levels were found to decrease (p < 0.01) with age. Unlike plasma NEFA and glucose, plasma alpha-amino nitrogen level increased (p < 0.01) as the buffaloes become older. Plasma NEFA and glucose concentrations in growing buffaloes were found to be positively correlated with plasma GH (r = 0.379 and 0.420 respectively), but these were non-significant (p > 0.01). However, plasma NEFA and glucose showed a good correlation (p < 0.01; r = 0.780 and 0.652 respectively) with plasma GH per 100 kg live weight. Plasma alpha-amino nitrogen exhibited non-significant (p > 0.01) negative correlation (r = -0.295) with plasma GH but a negative correlation (p < 0.01; r = -0.641) with GH per 100 kg BW. So, plasma metabolites showed a definite pattern of change during growth and these have a significant (p < 0.01) correlation with plasma GH per 100 kg BW than GH.  相似文献   

6.
Buffalo meat is tasty and indistinguishable from beef, and has been described as being lean and low in cholesterol in comparison with beef. However, little is known about the plasma hormone and metabolic profiles related to fat metabolism in buffalo, and how their levels are affected by species and sex. In this study levels of plasma hormones and metabolites were compared between species and sexes. Ten growing crossbred Brahman cattle and ten growing crossbred buffaloes (five males and five females in each), with an average age of 22 months were used. The animals were fed on an experimental diet composed of corn silage, brewer's spent grain and a concentrate mixture at a 50:30:20 ratio on a dry matter basis during a fattening period of 6 months. Blood samples were collected every month during the experiment, and were analysed for plasma leptin, insulin, glucose, triglyceride (TG) and total cholesterol (TC) concentrations. Plasma leptin, insulin and TC concentrations increased during fattening and were significantly (P < 0.05) higher in cattle than in buffaloes. These concentrations in cattle showed a big difference between sexes in comparison with buffaloes, and were higher in females than in males. The plasma glucose and TG concentrations did not differ (P > 0.05) between cattle and buffaloes.

The crude fat content of longissimus muscle was significantly higher in cattle than in buffalo. Differences in body fat deposition seem to have an influence on plasma leptin, insulin and TC concentrations differently between cattle and buffaloes.  相似文献   


7.
Leptin is a protein synthesized and secreted primarily by adipocytes, and the circulating leptin concentration is elevated in obese humans and rodents. Recently, we have established a sandwich enzyme-linked immunosorbent assay for canine leptin. In the present study, plasma leptin concentrations were measured in experimentally developed obese beagles and in clinically obese dogs. When 5 male beagles were given a high-energy diet for 3 months, all of them became obese and the plasma leptin concentration significantly increased from 2.4+/-1.2 to 4.9+/-0.9 ng/ml, positively correlating with body fat content estimated by the deuterium oxide dilution method (r=0.87). The leptin concentrations of plasma samples collected from 59 dogs in veterinary practices were compared with their body condition scores (BCS). The plasma leptin concentrations of obese dogs were 9.7+/-0.7 and 12.3+/-1.5 ng/ml at BCS=4 and BCS=5, respectively, which were significantly higher than those of optimal (BCS=3) dogs (2.7+/-0.3 ng/ml). There was no significant effect of sex and breed. A weak positive correlation (r=0.37) was found between the plasma leptin concentration and age, probably due to the lesser content of visceral fat in puppies younger than 1 year old. These results indicate that plasma leptin is a good index of adiposity in dogs regardless of breed, age and sex, and may be useful for quantitative assessment of obesity in small animal practice.  相似文献   

8.
Influence of obesity on plasma lipid and lipoprotein concentrations in dogs   总被引：3，自引：0，他引：3  
OBJECTIVE: To determine effects of obesity and diet in dogs on plasma lipid and lipoprotein concentrations by assaying plasma leptin and ghrelin concentrations and determining total plasma cholesterol and triglyceride concentrations as well as the concentrations of cholesterol and triglycerides in various lipoprotein classes (ie, very-low-density, low-density, and high-density lipoproteins). ANIMALS: 24 Beagles; 12 lean (mean [+/- SEM] body weight, 12.7 +/- 0.7 kg) and 12 chronically obese (21.9 +/- 0.8 kg) dogs of both sexes, between 1 and 9 years old. PROCEDURES: Total plasma cholesterol and triglyceride concentrations; lipoprotein cholesterol and triglyceride concentrations; and plasma ghrelin, leptin, free fatty acids, insulin, and glucose concentrations were measured and compared between lean and obese dogs, both of which were fed a complete and balanced maintenance diet. Chronically obese dogs were subsequently fed a high-protein low-energy diet to evaluate effects of diet composition on plasma lipid and lipoprotein measurements. RESULTS: Chronic obesity resulted in a significant decrease in plasma ghrelin concentration and a significant increase in plasma leptin, cholesterol, and triglyceride concentrations in dogs. High total plasma cholesterol and triglyceride concentrations resulted from increased cholesterol and triglyceride concentrations in all lipoprotein fractions. In obese dogs, modification of diet composition resulted in beneficial effects on plasma lipid and leptin concentrations, even before weight loss was observed. CONCLUSIONS AND CLINICAL RELEVANCE: Correlations exist between obesity and plasma measurements (ie, lipoproteins, leptin, insulin, and ghrelin) commonly associated with obesity. Modification of diet composition to control energy intake improves plasma lipid and leptin concentrations in obese dogs.  相似文献   

9.
The main objective of this study was to investigate the relationships between changes in plasma leptin concentration and feed intake or bodyweight in female and castrated male lambs with fattening. Four female and four castrated male lambs were used and were fed roughage and concentrate supplemented with beef tallow ad libitum for 28 weeks. Although the feed intake and bodyweight increased with fattening in both the castrated male and female lambs, they decreased at 24–28 weeks in the female lambs. At the end of fattening, the crude fat content in the muscle (loin) of the female lambs was significantly higher than in the castrated male lambs (P < 0.05), while the crude protein content in the loin and fillet meat was higher in the castrated male than in the female lambs (P < 0.05). The plasma leptin concentration showed high values at a later stage of fattening (P < 0.05). In the female lambs the plasma insulin concentration increased at a later stage of fattening (P < 0.05) and was positively correlated (P < 0.0001, r = 0.78) with plasma leptin. Plasma metabolites (glucose, nonesterified fatty acid, total cholesterol and triglyceride) concentrations were also changed with fattening. Plasma total cholesterol was positively related to plasma leptin, more closely in the female than in the castrated male lambs (in females, r = 0.63, P < 0.001; in males, r = 0.38, P < 0.01). The accumulation of body fat was probably accelerated by the consumption of a lot of concentrate feed supplemented with treated beef tallow and by the stimulation of insulin with fattening. Consequently, the plasma leptin concentration increased, especially toward the end of the fattening period. The decrease in feed intake and bodyweight after the 24th week of fattening was possibly caused by an increase in leptin that is involved in the homeostatic regulation of body energy by regulating appetite.  相似文献   

10.
OBJECTIVE: To measure and compare concentrations of selected blood lipids before and after thyroidectomy in horses. ANIMALS: 5 healthy adult mares. PROCEDURE: Mares were confirmed to be euthyroid. Thyroidectomy was performed, and hypothyroidism was confirmed. Selected blood lipid variables were measured before hypothyroidism was induced and weekly for 4 weeks after induction. Plasma concentrations of very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), serum triglyceride (TG), total cholesterol (TC), and nonesterified fatty acid (NEFA) were measured. The composition of VLDL and LDL also was examined. RESULTS: Mean plasma concentrations of VLDL and LDL increased significantly after thyroidectomy. By 4 weeks after thyroidectomy, a ninefold increase in mean plasma concentration of VLDL and a threefold increase in LDL, compared with baseline values, were detected. After thyroidectomy, mean percentage of TG in VLDL increased significantly, whereas free cholesterol and cholesterol ester content decreased. Mean percentage of TG in LDL also increased by 3 to 4 weeks after thyroidectomy. Serum concentrations of TG and TC increased, whereas serum NEFA concentration decreased. CONCLUSIONS: Hypothyroidism significantly alters blood lipid concentrations of horses. After thyroidectomy, markedly high VLDL concentration, appearance of TG-rich VLDL, increased serum concentrations of TG and TC, and decreased blood concentration of NEFA were evident. CLINICAL RELEVANCE: Examination of blood lipid concentrations of horses may be useful for detecting naturally acquired hypothyroidism.  相似文献   

11.
OBJECTIVE: To measure and compare the concentration and composition of very low-density lipoprotein (VLDL) in plasma and selected lipids in serum of horses fed mixed grass hay ad libitum or denied feed for 36 hours. ANIMALS: 4 healthy adult mares. PROCEDURE: Mares were either fed mixed grass hay ad libitum or denied feed for 36 hours beginning at 8:00 AM. Blood samples were collected every 2 hours during the study period and analyzed for nonesterified fatty acid (NEFA), triglyceride (TG), VLDL, and glucose concentrations and composition of VLDL. RESULTS: Withholding feed significantly increased mean serum concentrations of NEFA. By 36 hours, a 16-fold increase in mean serum NEFA concentration and 2-fold increase in mean plasma VLDL concentration, compared with baseline values, were detected. Mean plasma TG concentrations significantly increased with time in feed-deprived horses. Significantly lower overall mean plasma glucose concentrations were detected in feed-deprived horses. Mean percentage of protein in VLDL was significantly lower in feed-deprived horses. Plasma VLDL concentrations varied widely among horses in response to withholding feed. Plasma TG and VLDL concentrations remained unaltered in 2 horses. CONCLUSIONS AND CLINICAL RELEVANCE: Withholding feed significantly increases blood lipid concentrations in horses, but individual horses respond differently. Serum NEFA concentrations were increased in all 4 horses denied feed, indicating mobilization of tissue triglyceride stores. Variation in plasma VLDL concentration in response to withholding feed suggests that its metabolism is strongly influenced by other, as yet undetermined, factors in horses. Differences in the plasma VLDL concentrations among horses in response to withholding feed may be used as an indication of susceptibility to the hyperlipemic syndrome of Equidae.  相似文献   

12.
We determined the effects of short-term fasting and refeeding on temporal changes in plasma concentrations of leptin, insulin, insulin-like growth factor- 1 (IGF-1), growth hormone (GH), glucose, and nonesterified fatty acids (NEFA), in early lactating cows, non-lactating pregnant cows, and postpubertal heifers. In experiment 1, Holstein cows in early lactation were either fed ad libitum (Control, n=5) or feed deprived for 48 h (Fasted, n=6). Plasma leptin, insulin, and glucose concentrations rapidly declined (P<0.05) within 6h, and IGF-1 by 12h, but all these variables sharply returned to control levels (P>0.10) within 2h of refeeding. Plasma NEFA and GH concentrations were elevated (P<0.05) by 4 and 36 h of fasting and returned to control levels (P>0.10) by 8 and 24h after refeeding, respectively. In experiment 2, four ruminally cannulated pregnant non-lactating Holstein cows were used in a cross-over design and were fasted for 48 h (Fasted) or fasted with partial evacuation of rumen contents (Fasted-Evac). The plasma variables measured did not differ (P>0.10) between Fasted and Fasted-Evac cows. Plasma leptin, insulin, and IGF-1 concentrations were reduced by 10, 6, and 24h of fasting, respectively, in Fasted-Evac cows; and these variables were reduced by 24h in Fasted cows (P<0.05). Plasma glucose levels were reduced (P<0.05) by 48 h of fasting in both groups of fasted animals. Plasma NEFA and GH levels were increased (P<0.05) by 12 and 48 h of fasting, respectively. In experiment 3, postpubertal Holstein heifers were either fed ad libitum (Control, n=4) or feed deprived for 72 h (Fasted, n=5). Concentrations of leptin, insulin, IGF-1, and glucose in plasma were reduced (P<0.05) by 24, 10, 24, and 48 h of fasting, respectively. Plasma NEFA concentrations increased (P<0.05) by 4h, of fasting while GH levels were not significantly (P>0.10) affected by fasting. Collectively, our data provide evidence that plasma leptin concentrations are reduced with short-term fasting and rebound on refeeding in dairy cattle with the response dependent on the physiological state of the animals. Compared to the rapid induction of hypoleptinemia with fasting of early lactation cows, the fasting-induced hypoleptinemia was delayed in non-lactating cows and postpubertal heifers.  相似文献   

13.
OBJECTIVE: To compare plasma total calcium, phosphorus, magnesium, nonesterified fatty acids (NEFA), beta hydroxy butyrate (BHB), and glucose concentrations in parturient dairy cows that were fed an anionic prepartum diet between those with and without retained fetal membranes (RFM) at 24 hours after parturition. ANIMALS: 152 Holstein cows that calved during October through December of 1997 PROCEDURE: All cows were fed an anionic prepartum diet. Blood sample was taken within 6 hours after parturition from randomly selected cows. Thirty-nine cows had a diagnosis of RFM at 24 hours after parturition; 113 were not affected with RFM. At calving, body condition score (BCS; 1 [thin] to 5 [obese]), parity, and calving difficulty score were recorded. Plasma calcium, phosphorus, magnesium, NEFA, BHB, and glucose concentrations were compared between cows with or without RFM. RESULTS: Cows with RFM had significantly lower plasma calcium concentration soon after calving, compared with cows without RFM. Cows with a parity of > or = 3 had significantly lower plasma concentrations of calcium and higher concentrations of magnesium, compared with cows with a parity of 1 or 2. Cows with a BCS of > or = 3.25 at calving had significantly higher plasma concentrations of BHB than cows with a BCS of 2.75 to 3.0. Cows with dystocia had significantly higher plasma concentrations of glucose, compared with cows without dystocia. CONCLUSIONS AND CLINICAL RELEVANCE: In parturient cows fed a prepartum anionic diet, those with RFM have lower plasma calcium concentrations than cows without RFM, although this association does not prove a cause-effect relationship.  相似文献   

14.
The objective of the present study was to examine the relationship between plasma leptin levels and fat distribution in crossbred steers. Twenty-four crossbred steers (Japanese Black × Holstein) were used in this study. Six steers belonged to the growing phase (11 months of age), and 18 steers to the finishing phase (from 21 to 28 months of age). Plasma leptin levels correlated positively with body fat weight ( r  = 0.807, P  < 0.01), body fat percentage ( r  = 0.802, P  < 0.01), visceral fat weight ( r  = 0.807, P  < 0.01), visceral fat percentage ( r  = 0.780, P  < 0.01), subcutaneous fat weight ( r  = 0.745, P  < 0.01), subcutaneous fat percentage ( r  = 0.734, P  < 0.01), intermuscular fat weight ( r  = 0.793, P  < 0.01), intermuscular fat percentage (0.775, P  < 0.01), renal fat weight ( r  = 0.694, P  < 0.01), renal fat percentage ( r  = 0.642, P  < 0.01), subcutaneous fat thickness ( r  = 0.755, P  < 0.01), intermuscular fat thickness ( r  = 0.721, P  < 0.01), beef marbling score ( r  = 0.706, P  < 0.01) and the crude fat content of Musculus longissimus thoracis ( r  = 0.592, P  < 0.01). The location of fat deposits did not affect the correlation values. However, when steers were divided into growing ( n  = 6) and finishing ( n  = 18) groups, there was no significant correlation between plasma leptin levels and the carcass characteristics related to fat deposition (fat weight, fat percentage, carcass traits) in either group. These results suggest that plasma leptin levels in crossbred steers positively correlate with body fat content and carcass traits when these parameters vary widely.  相似文献   

15.
The hormonal mediators of obesity-induced insulin resistance and compensatory hyperinsulinemia in dogs have not been identified. Plasma samples were obtained after a 24-h fast from 104 client-owned lean, overweight, and obese dogs. Plasma glucose and insulin concentrations were used to calculate insulin sensitivity and β-cell function with the use of the homeostasis model assessment (HOMAinsulin sensitivity and HOMAβ-cell function, respectively). Path analysis with multivariable linear regression was used to identify whether fasting plasma leptin, adiponectin, or glucagon-like peptide-1 concentrations were associated with adiposity, insulin sensitivity, and basal insulin secretion. None of the dogs were hyperglycemic. In the final path model, adiposity was positively associated with leptin (P < 0.01) and glucagon-like peptide-1 (P = 0.04) concentrations. No significant total effect of adiposity on adiponectin in dogs (P = 0.24) was observed. If there is a direct effect of leptin on adiponectin, then our results indicate that this is a positive relationship, which at least partly counters a negative direct relationship between adiposity and adiponectin. Fasting plasma leptin concentration was directly negatively associated with fasting insulin sensitivity (P = 0.01) and positively associated with β-cell function (P < 0.01), but no direct association was observed between adiponectin concentration and either insulin sensitivity or β-cell function (P = 0.42 and 0.11, respectively). We conclude that dogs compensate effectively for obesity-induced insulin resistance. Fasting plasma leptin concentrations appear to be associated with obesity-associated changes in insulin sensitivity and compensatory hyperinsulinemia in naturally occurring obese dogs. Adiponectin does not appear to be involved in the pathophysiology of obesity-associated changes in insulin sensitivity.  相似文献   

16.
Leptin is an adipocytokine mainly expressed by adipose tissue. Secretion of leptin in healthy animals is closely related to fat mass and metabolic activity. The aim of this study was to investigate plasma leptin variations, in relation to nutritional and exercise parameters in adult show horses during a work season. EDTA-blood samples were taken at rest from 37 Iberian horses. Body weight, body condition score and fat percentage determined by ultrasonic measurement of rump fat thickness were measured. Plasma leptin was determined with a multi-species RIA kit. Linear mixed effects model was used to assess relationship between plasma leptin and other biological parameters. Plasma leptin concentration was <12.6 ng/ml (mean = 2.8 ± 1.6 ng/ml) and was significantly higher during training periods (p < 0.0001) (4.5 ± 1.7 ng/ml) than in show periods (2.0 ± 1.1 ng/ml), despite a significant increase (p < 0.0001) in energy intake. The body weight remained almost constant. The plasma leptin concentrations were significantly affected by exercise (p < 0.0001), body weight (p = 0.04) and BCS (p < 0.0001), but were not affected by percentage of fat. In conclusion, the marked decrease in leptin values observed during a period of intense (i.e. excessive) exercise could result from an adaptation to cumulative alterations in energy balance, to exercise per se or to a combination of both.  相似文献   

17.
The effects of weight loss on hormonal and biochemical blood parameters were measured monthly [carnitine, creatinine, urea, free T4 (fT4), total T4 (TT4), plasma alkaline phosphatases (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), potassium and total proteins] or bimonthly [cholesterol, triglycerides, non-esterified fatty acids (NEFA), insulin-like growth factor I (IGF-I), glucose, insulin] in eight obese Beagles dogs fed either a high protein dry diet, DP (crude protein 47.5%, on dry matter basis) or a commercial high fibre diet, HF (crude protein 23.8%, crude fibre 23.3%). The dogs were allotted to two groups according to sex and body weight (BW) and they were respectively fed with the DP or the control HF diet during 12-26 weeks, until they reach their optimal BW. The plasma basal triglycerides and cholesterol concentrations were decreased by the two diets but the difference was only significant for the DP diet. The plasma mean NEFA concentration increased regularly over the period with the HF diet, without significant difference between the two diets. No effect of diet or weight loss was observed on plasma carnitine, urea, creatinine, ALP, AST, ALT, potassium, TT4, FT4, IGF-I, glucose and insulin. Weight loss induced a decrease in fT4 plasma concentration (p < 0.001). The high protein diet allowed a safe weight loss.  相似文献   

18.
The objective of this study was to evaluate, in dogs, the effects of obesity and weight loss on plasma total ghrelin and leptin concentrations. Twenty-four Beagle dogs, 12 control lean and 12 obese dogs of both genders and aged between 1 and 9 years, were used for the experiments. Mean body weight was 12.7+/-0.7 kg for the lean group and 21.9+/-0.8 kg for the obese group. The trial was divided into three phases. During phase 1, all 24 Beagle dogs were fed a maintenance diet. During phase 2, the obese dogs were submitted to a weight loss protocol with a high protein-low energy diet. The weight loss protocol ended once dogs reached optimal body weight. During phase 3, the dogs that were submitted to the weight loss protocol were maintained at their optimal body weight for 6 months. Plasma total ghrelin, leptin, insulin and glucose concentrations were measured to evaluate the effects of obesity and weight loss on these parameters in dogs. Body weight, body condition score, thoracic and pelvic perimeters, and ingested food amounts were also recorded during the study. Obese dogs demonstrated a significant decrease in plasma ghrelin and a significant increase in plasma leptin and insulin concentrations when compared with control dogs. During weight loss, significant increases in plasma total ghrelin and glucose and significant decreases in plasma leptin and insulin were observed. The increase in plasma ghrelin concentrations seemed to be transient. Body weight and the morphometric parameters correlated positively with leptin concentrations and negatively with total ghrelin concentrations. These results suggest that ghrelin and leptin could play a role in dogs in the adaptation to a positive or negative energy balance, as observed in humans.  相似文献   

19.
Diet-induced central obesity and insulin resistance in rabbits   总被引：4，自引：0，他引：4  
The present study was designed to examine whether rabbits fed a diet containing high fat and sucrose could develop obesity and insulin resistance (IR), the major pathophysiological features of metabolic syndrome. Male Japanese white rabbits were fed either a normal chow diet (control) or high fat and sucrose diet (HFSD) for 36 weeks. Plasma levels of triglycerides (TG), total cholesterol (TC), glucose and insulin were measured. To evaluate glucose metabolism, we performed an intravenous glucose tolerance test. In addition, we compared adipose tissue accumulation in HFSD-fed rabbits with that in normal rabbits. HFSD constantly and significantly led to an increase in body weight of HFSD-fed rabbits, caused by significantly higher visceral adipose tissue accumulation. Although there were no differences in plasma TG, TC, glucose, insulin levels and blood pressure between the two groups, HFSD-fed rabbits showed impaired glucose clearance associated with higher levels of insulin secretion compared to control rabbits. Our results showed that HFSD induced IR and increased adipose accumulation in rabbits, suggesting that HFSD-fed rabbits may become a model for research on human IR and obesity.  相似文献   

20.
蛋鸡血浆甘油三酯与蛋黄性状关系的研究   总被引：3，自引：1，他引：2  
本实验对蛋鸡血浆甘油三酯 (Triglyceriche ,TG)浓度进行高、低选择之后 ,测定了两个世代的产蛋早期的褐壳鸡的血脂成分 (血浆中胆固醇、磷酯、游离脂肪酸 )及其鸡的蛋黄性状 (蛋黄比例、蛋黄胆固醇含量 ) ;且以父系半同胞法估计了血脂和蛋黄性状的遗传参数。研究了与鸡体脂肪代谢关系密切的血脂成分和蛋黄性状的变化规律及其之间的相互关系 ,来寻找能降低蛋黄胆固醇的新途径。结果表明 :血浆甘油三酯的变异系数较大为 5 3.5 2 % ;血浆甘油三酯、蛋黄比例和相对蛋中胆固醇含量的遗传力较高分别是 0 .2 74、0 .90 2、0 .30 4 ,它们之间的遗传相关分别是 0 .2 71、0 .36 6。即血浆甘油三酯可以作为间接选择蛋中胆固醇含量的指标。  相似文献   

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