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Genetically obese and lean pigs were fed isonitrogenous-isoenergetic (digestible energy) amounts of a high or low fat diet from 25 kg body weight. Obese pigs gained less and required more feed per unit gain than lean pigs. Lean pigs were more muscular with less fat than obese pigs. Obese pigs utilized more dietary amino acids for energy (greater plasma urea N) than did lean pigs. Weight gain was similar at all intermediate periods in obese pigs fed the two diets. However, gain tended (P less than or equal to .10) to be greater and the ratio of dietary energy intake to gain tended (P less than or equal to .10) to be less in obese pigs fed high compared with low fat diets. Similar results were observed in lean pigs fed the two diets. The high fat diet produced more carcass adipose tissue deposition in both strains after 20 wk of feeding (detectable by ultrasound at 14, but not at 7 wk). Adipose tissue lipogenic rate (glucose incorporation) was similarly depressed by fat feeding in both obese and lean pigs. Obese and lean pigs both utilized dietary carbohydrate and fat differentially but there was no indication of genetic divergence regarding this utilization. In both strains of pigs, energy from the fat-enriched diet was preferentially partitioned into carcass adipose tissue. 相似文献
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Effect of colostrum intake on plasma glucose, non-esterified fatty acid and glucoregulatory hormone patterns in the neonatal pig 总被引：1，自引：0，他引：1
The effect of colostrum on endocrine and metabolic factors affecting glucose homeostasis was evaluated in 60 neonatal pigs that were fasted, fed (nursed ad libitum) or limit-fed colostrum (25% ad libitum, 4-hr interval feeding). Plasma acquired at birth (t0), and after 10, 20 and 30 hr (t10, t20 and t30, respectively) was analyzed for glucose, non-esterified fatty acids (NEFA), and the glucoregulatory hormones--insulin, glucagon, cortisol, growth hormone and catecholamines. The concentration of glucose and NEFA was similar among treatment groups at birth and increased in proportion to the quantity of colostrum consumed. Pigs fed ad libitum achieved and maintained a higher (greater than or equal to 40%; P less than .01) glucose concentration when compared to fasted neonates. Limit-fed counterparts also achieved and maintained higher levels, with glucose concentration being approximately 20% higher throughout (P less than .05). Fed pigs maintained NEFA concentrations which were approximately 2.5-fold to 4-fold greater than that of fasted pigs (P less than .05). Likewise, limit-fed pigs tended (P = .19) to have elevated NEFA concentrations and a lower (P less than .05) insulin:glucagon molar ratio. An inverse relationship was observed between colostrum intake and plasma concentrations of cortisol and growth hormone. Concentrations of epinephrine and norepinephrine tended (P greater than .10) to be elevated in fed pigs, relative to those of fasted counterparts. Provision of even limited quantities of colostrum is therefore beneficial to the glucoregulatory response in newborn pigs. 相似文献
4.
H J Mersmann 《Journal of animal science》1985,60(1):131-135
In vitro lipolytic rate was determined in adipose tissue from genetically obese and lean pigs. There were about 20 pigs/genetic strain at 25 and 80 kg and 10 pigs/strain at 50 kg body weight. When expressed on a cellular basis, the in vitro adipose tissue basal (no exogenous hormone) lipolytic rate was similar in obese and lean pigs at 25 and 50 kg body weight. At 80 kg body weight the basal rate was greater in obese than in lean pigs. The in vitro adipose tissue epinephrine-stimulated lipolytic rate expressed on a cell basis was greater at 25 kg, was similar at 50 kg body weight and tended (P less than or equal to .1) to be greater at 80 kg in obese compared with lean pigs. The in vitro sensitivity of lipolysis to epinephrine was slightly greater in lean compared with obese pigs. The data obtained in vitro indicate that obese pigs do not have low adipose tissue lipolytic rates compared with lean pigs. Consequently, adipose tissue lipolysis does not appear to be a major metabolic factor leading to the excessive fat accretion in these obese pigs. 相似文献
5.
The time course for changes in plasma free fatty acid and triglyceride concentration after removal of feed was established. Genetically obese and lean lines of pigs, two types of crossbred female pigs and a group of male pigs were used to establish the relationship between circulating free fatty acid or triglyceride concentrations and adiposity. Pigs were weighed, ultrasonically probed for backfat thickness, bled in a fed state and again in the fasted state. Plasma was analyzed for free fatty acid and triglyceride concentration. Fasting increased plasma free fatty acid, but only slightly increased triglyceride concentrations. There were several significant correlations between backfat thickness and plasma lipid concentrations; however, the low magnitude and inconsistency of these correlations precludes use of plasma lipid concentrations as indicators of adiposity in swine. Fasted obese pigs had lower plasma fatty acid concentrations than lean pigs at 2, 4 and 6 mo of age. If these plasma levels represent in vivo mobilization of fat, the results probably contrast with previously reported in vitro results wherein adipose tissue from obese pigs had lipolytic rates expressed on a cellular basis that were equal to or greater than those form lean pigs. 相似文献
6.
A 2 X 2 factorial arrangement with two genotypes of pigs (genetically obese and lean) and two dietary treatments (basal, a 16% protein corn-soybean meal standard grower diet, and basal +220 ppm thyroprotein as iodinated casein) was used. The 28 gilts were housed individually and fed ad libitum from 121 d of age until slaughtered at 99 kg body weight. Compared with lean pigs, genetically obese pigs had significantly lower average daily gain and gain/feed, greater backfat thickness, smaller loin eye area, shorter carcass length and lower circulating plasma triiodothyronine (T3) concentration. However, both total plasma and free thyroxine (T4) concentrations were similar comparing obese and lean pigs. Supplementation with thyroprotein increased circulating plasma concentration of both total and free T4 and produced interactions with genotype in affecting daily gain and gain/feed of pigs. Thyroprotein reduced both daily gain and gain/feed in obese pigs, but increased daily gain and gain/feed in lean pigs. It is suggested, similar to the case with obese mice, that heat production of our genetically obese pigs may be more sensitive to thyroprotein administration compared with similar treatment of lean animals. 相似文献
7.
Sera-controlled preadipocyte growth in culture: an ontogeny study with sera from lean and obese pigs
Genetically lean and obese swine were used to investigate the control of preadipocyte growth in culture by porcine serum. Sera were collected from fetuses from obese and lean strains at 70, 90 and 110 d of gestation. Postnatal serum samples were collected from both lines of pigs at 23 to 27 kg. Rat preadipocytes were isolated and grown in culture. Preadipocyte and stromal-vascular cell proliferation was greater in cultures grown in sera obtained postnatally than in cultures grown in sera from fetuses. Sera from lean and obese fetuses were equipotent in promoting cell proliferation. Glycerol-phosphate dehydrogenase (GPDH) activity was higher in cultures fed serum from obese pigs and fetuses than in cultures fed serum from lean pigs and fetuses. Cultures grown in serum from obese fetuses and pigs had soluble protein levels similar to cultures grown with serum from lean pigs and fetuses. These results demonstrate that serum from genetically obese swine, in the pre-obese (fetal) and obese (postnatal) state, caused increased adipogenic activity in adipocytes in culture. 相似文献
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The effects of estrogen and fasting on hepatic metabolism were studied by an arteriovenous difference technique in six multicatheterized ewes. In each experiment samples were collected during fed and 3- and 5-day fasted states before, and 10 to 17 days after the animals had been implanted with 550 mg of estradiol-17 beta. The implants elevated plasma estradiol five- to seven-fold. Plasma concentrations of insulin and triglyceride (TG) were increased (P less than 0.01) by 131% and 62% respectively by estradiol in fed sheep. Concurrent circulating concentrations of glucose, glycerol, free fatty acids, and beta-hydroxybutyrate were unaffected. During fasting estradiol elevated circulating concentrations of beta-hydroxybutyrate slightly, while levels of other metabolites and insulin were not different from fasted controls. In fed animals estradiol had no effect on the net hepatic uptake (NHU) of TG or glycerol but during fasting estradiol reduced the NHU of TG and glycerol by 47% and 31% (P less than 0.01) respectively. In addition, estradiol reduced the net hepatic production of beta-hydroxybutyrate in fed, but not in fasted animals. Net hepatic exchanges of glucose, or FFA were not affected by estradiol in either the fed or fasted state. Fasting increased the NHU of TG (P less than 0.05) and glycerol (P less than 0.01). The results of this study suggest that estradiol, at physiological concentrations, has lipotropic and anti-ketogenic effects on the ruminant liver. However, the anti-ketogenic effect is not apparent in fasted animals. Secondly, it appears that the hepatic lipidosis which often occurs in ruminants during negative energy balance is due largely to an increase in the NHU of circulating TG. 相似文献
9.
Thirty-two pigs (1 d old) were used to determine if exogenous glucagon and(or) free fatty acids (FFA oleic acid) would enhance gluconeogenesis and glucose homeostasis during fasting. Pigs were acquired at birth, fitted with an indwelling arterial cannula (via umbilicus) and fasted 24 h to deplete liver glycogen. A jugular cannula was inserted nonsurgically 8 to 10 h before initiation of a primed-continuous infusion consisting of control (excipient), glucagon (Glu), oleic acid (FFA), or both glucagon and oleic acid (Glu-FFA). Plasma Glu averaged 395 pg/ml preinfusion and was similar across treatments. The concentration increased fivefold (P less than .05) by 80 min for Glu and Glu-FFA pigs and remained constant thereafter (160 min: 2,379, 2,258 pg/ml; 240 min: 2,355, 2,274 pg/ml, respectively). Glucagon infusion did not alter plasma glucose after 240 min of infusion (control, 50 vs Glu, 51 mg/dl); however, Glu-FFA effected an increase (60 mg/dl, P less than .10). In contrast, pigs infused with FFA alone had a lower glucose concentration (40 mg/dl, P less than .10). Rate of glucose synthesis was determined using liver slices, acquired immediately postinfusion, with alanine and lactate as substrate (7.5 mM). The rate of synthesis was not altered by Glu or Glu-FFA infusion (2.91, 2.43 mumol glucose X g-1 X h-1 vs 2.91 for control). In contrast, exogenous FFA reduced synthesis to 1.85 mumol glucose X g-1 X h-1 (P less than .05) with lactate as substrate. It appears that Glu is not the primary factor limiting gluconeogenesis in fasting newborn pigs.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
10.
Effects of ractopamine on genetically obese and lean pigs 总被引：2，自引：0，他引：2
Twenty-eight genetically obese and 24 lean barrows (65.0 and 68.7 kg average BW, respectively) were allotted within genotype to a 16% CP corn-soybean meal basal diet or this basal diet + 20 ppm ractopamine (a phenethanolamine beta-adrenergic agonist) and allowed ad libitum access to feed for 48 d. Compared to lean pigs, obese pigs had lower ADG, gain to feed ratio, longissimus muscle area, predicted amount of muscle, and weights of trimmed loin and ham, ham lean, heart, spleen, kidney and gastrointestinal tract (P less than .05). Obese pigs also had shorter carcass but higher dressing percentage, backfat thickness, fat depth, fat area, untrimmed loin weight and fasting plasma urea N concentration (P less than .05). Dietary supplementation with 20 ppm ractopamine reduced daily feed intake and improved gain to feed ratio in both lean and obese pigs (P less than .05). Pigs fed ractopamine had shorter carcasses, less fat depth and fat area, smaller weights of stomach and colon plus rectum, but higher dressing percentages, longissimus muscle areas, weights of trimmed Boston butts, picnics and loins, ham lean and predicted amounts of muscle than pigs not fed ractopamine (P less than .05). Supplemental ractopamine had no effect on fasting plasma concentrations of urea N, nonesterified fatty acids, triglyceride or glucose (P greater than .05). No genotype x ractopamine interactions for the criteria described above were detected (P greater than .05). These results suggest that ractopamine will improve the efficiency of feed utilization and carcass leanness in swine with different propensities for body fat deposition. 相似文献
11.
Twenty-four genetically obese and 24 lean barrows were allotted within genotype to either a 16% CP corn-soybean meal basal diet, the basal + .69 ppm cimaterol or the basal + 1.38 ppm cimaterol. Pigs had ad libitum access to their diets from 59.3 kg to 104.5 kg body weight. No genotype x cimaterol interactions were detected (P greater than .05). Neither genotype nor cimaterol supplementation had any effect (P greater than .05) on average daily weight gain or gain-to-feed ratio. Compared with lean pigs, obese pigs had higher fasting plasma urea nitrogen (BUN), a smaller gastrointestinal tract and a greater dressing percentage with a shorter and fatter carcass (P less than .05). Cimaterol produced a higher fasting plasma BUN, a greater dressing percentage with a leaner carcass and a higher shear force value for loin chops (P less than .05). Cimaterol also tended (P less than .10) to increase heart weight. However, no difference was observed in these measurements between pigs fed .69 or 1.38 ppm cimaterol. In lean pigs fed the basal or .69 ppm cimaterol diet, there was no difference (P greater than .05) in the 8 to 24 h postprandial whole-animal heat production. Cimaterol effectively decreased fat deposition and increased lean accretion both in genetically obese and in lean pigs; there were no differential responses to cimaterol in pigs with different propensities to deposit body fat. 相似文献
12.
Effect of colostrum intake on hepatic gluconeogenesis and fatty acid oxidation in the neonatal pig 总被引：1，自引：0，他引：1
A total of 24 newborn pigs were used to determine 1) the relationship between the quantity of colostrum consumed and the capacity for gluconeogenesis and fatty acid oxidation and 2) whether fatty acid oxidation limits gluconeogenesis in isolated hepatocytes. Neonatal pigs were obtained prior to nursing and allotted to one of three treatment groups; fed (ad libitum), limit-fed (25% of fed group), or fasted. Hepatocytes were isolated when pigs were 24 h old. Colostrum intake altered the metabolic status of neonates such that the capacity for glucose synthesis and oxidation of octanoate increased with intake. Glucose synthesis with lactate as the substrate was greater (P less than .01) for fed pigs (10.79 mumol glucose.h-1.mg DNA-1) than for either limit-fed (6.56) or fasted counterparts (4.78), which were similar (P greater than .10). Colostrum intake failed to stimulate synthesis from alanine. The oxidation rate for octanoate was similar for fed and limit-fed pigs (.62 and .61 nmol CO2.h-1.mg DNA-1, respectively) but greater (P less than .05) than that observed for fasted counterparts (.36). Oxidation of octanoate (2 mM) was approximately 30-fold greater than for oleate (1 mM); oxidation of the latter was not affected by either colostrum intake or the addition of carnitine (1 mM). The increase in octanoate oxidation, however, did not elicit an increase in glucose synthesis by fasting pigs with either lactate or alanine as precursors. Thus, we conclude that gluconeogenesis is a function of colostrum intake and that reducing equivalents and(or) ATP may not be primary factors limiting glucose synthesis in pigs fasted from birth. 相似文献
13.
Wilkins C Long RC Waldron M Ferguson DC Hoenig M 《American journal of veterinary research》2004,65(8):1090-1099
OBJECTIVE: To determine whether dietary fatty acids affect indicators of insulin sensitivity, plasma insulin and lipid concentrations, and lipid accumulation in muscle cells in lean and obese cats. ANIMALS: 28 neutered adult cats. PROCEDURE: IV glucose tolerance tests and magnetic resonance imaging were performed before (lean phase) and after 21 weeks of ad libitum intake of either a diet high in omega-3 polyunsaturated fatty acids (3-PUFAs; n = 14) or high in saturated fatty acids (SFAs; 14). RESULTS: Compared with the lean phase, ad libitum food intake resulted in increased weight, body mass index, girth, and percentage fat in both groups. Baseline plasma glucose or insulin concentrations and glucose area under the curve (AUC) were unaffected by diet. Insulin AUC values for obese and lean cats fed 3-PUFAs did not differ, but values were higher in obese cats fed SFAs, compared with values for lean cats fed SFAs and obese cats fed 3-PUFAs. Nineteen cats that became glucose intolerant when obese had altered insulin secretion and decreased glucose clearance when lean. Plasma cholesterol, triglyceride, and non-esterified fatty acid concentrations were unaffected by diet. Ad libitum intake of either diet resulted in an increase in both intra- and extramyocellular lipid. Obese cats fed SFAs had higher glycosylated hemoglobin concentration than obese cats fed 3-PUFAs. CONCLUSION AND CLINICAL RELEVANCE: In obese cats, a diet high in 3-PUFAs appeared to improve long-term glucose control and decrease plasma insulin concentration. Obesity resulted in intra- and extramyocellular lipid accumulations (regardless of diet) that likely modulate insulin sensitivity. 相似文献
14.
The disposition of spiramycin and lincomycin was measured after intravenous (i.v.) and oral (p.o.) administration to pigs. Twelve healthy pigs (six for each compound) weighing 16–43 kg received a dose of 10 mg/kg intravenously, and 55 mg/kg (spiramycin) or 33 mg/kg (lincomycin) orally in both a fasted and a fed condition in a three-way cross-over design. Spiramycin was detectable in plasma up to 30 h after intravenous and oral administration to both fasted and fed pigs, whereas lincomycin was detected for only 12 h after intravenous administration and up to 15 h after oral administration. The volume of distribution was 5.6 ± 1.5 and 1.1 ± 0.2 L/kg body weight for spiramycin and lincomycin, respectively. For both compounds the bioavailability was strongly dependent on the presence of food in the gastrointestinal tract. For spiramycin the bioavailability was determined to be 60% and 24% in fasted and fed pigs, respectively, whereas the corresponding figures for lincomycin were 73% and 41%. The maximum plasma concentration of spiramycin (Cmax) was estimated to be 5 μg/mL in fasted pigs and 1 μg/mL only in fed pigs. It is concluded that an oral dose of 55 mg/kg body weight is not enough to give a therapeutically effective plasma concentration of spiramycin against species of Mycoplasma, Streptoccocus, Staphylococcus and Pasteurella multocida. The maximum plasma concentration of lincomycin was estimated to be 8 μg/mL in fasted pigs and 5 μg/mL in fed pigs, but as the minimum inhibitory concentration for lincomycin against Actinobacillus pleuropneumoniae and P. multocida is higher than 32 μg/mL a therapeutically effective plasma concentration could not be obtained following oral administration of the drug. For Mycoplasma the MIC90 is below 1 μg/mL and a therapeutically effective plasma concentration of lincomycin was thus obtained after oral administration to both fed and fasted pigs. 相似文献
15.
Carcass, muscle and meat characteristics of lean and obese pigs 总被引：1，自引：0，他引：1
Six pigs obtained from a lean selected strain and six pigs obtained from an obese selected strain were slaughtered at about 110 kg live-animal weight. Carcasses were evaluated; hams were dissected into bone, skin, fat and lean, and loin samples were obtained for fiber type characteristics, percentage of fat and moisture, collagen analysis, sensory characteristics, textural properties and objective color analysis. Carcasses from lean pigs were longer, had less backfat and larger longissimus muscle cross-sectional areas than carcasses obtained from obese pigs. Hams from lean pigs had less fat, more bone and more lean than hams from carcasses of obese pigs. The percentages and cross-sectional areas of red and white muscle fibers of the longissimus muscle from lean and obese pigs were not different. However, lean pigs had intermediate fibers that were only 79% as large (P less than .10) as intermediate muscle fibers from obese pigs. Intermediate fibers represented only 7 and 10% of total fiber area, whereas white fibers represented 84 and 79% of total fiber area in longissimus muscle of lean and obese pigs, respectively. Overall, lean pigs tended to possess fewer fibers (-16%) per unit of area than obese pigs, indicating that total muscle fiber hypertrophy was partially responsible for the increased longissimus muscle area of the lean strain. Sensory properties of longissimus meat samples from lean and obese strains were not different. However, the shear force requirement of the longissimus samples from the lean strain were slightly, but significantly (P less than .10), higher than those from the obese strain. No differences were observed in meat color. 相似文献
16.
J Le Dividich T Esnault B Lynch R Hoo-Paris C Castex J Peiniau 《Journal of animal science》1991,69(6):2480-2488
The effects of colostral fat level on fat deposition and plasma concentrations of glucose, insulin, and free fatty acids (FFA) were determined in 28 newborn pigs during the first postnatal day. Soon after birth, pigs were allotted to four treatments groups. Group 1 was killed at birth. The remaining pigs were fed intragastrically sow colostrum that contained high (10.2%; HFC), normal (4.8%; NFC) or low (1.0%; LFC) levels of total fat at the rate of 15 to 18 g/kg birth weight at 65- to 70-min intervals. A total of 21 feedings was provided and pigs were killed 1 h after the last feeding. Body fat deposition increased linearly (P less than .01) with the amount of ingested fat by .32 (+/- .04) g per 1-g increase in fat intake. Fatty acid composition of the pigs changed toward that of the colostrum with increased fat in colostrum. More liver glycogen was lost (P less than .01) in pigs given LFC. Plasma concentrations of glucose and insulin were similar in pigs fed HFC and NFC. After the 11th feeding (14 h postnatal), LFC resulted in lower plasma glucose concentrations (P less than .05) than HFC or NFC. Plasma insulin concentrations also were lower in pigs fed LFC. Plasma FFA concentrations remained unchanged in pigs fed LFC but increased with both fat content in colostrum (P less than .05) and time (P less than .05) in the other two groups. Colostral fat plays a major role in the supply of energy and in glucose homeostasis in the neonatal pig. 相似文献
17.
Changes in serum concentrations of glucose and insulin after iv injection of a low (20 mU/kg) and high (200 mU/kg) dose of bovine insulin were used to quantify insulin resistance and calculate kinetic variables of injected insulin, respectively, in four obese and four lean heifers. Serum samples from jugular venous blood were collected 60, 45, 30, 15 and 1 min before and 2.5, 5, 10, 20, 30, 40, 60, 80, 100, 120, 150, 180, 210 and 240 min after each treatment. Mean (+/- SE) pretreatment concentration of insulin (microU/ml) was higher (P less than .01) in obese (50 +/- 6.6) than lean (20 +/- 1.8) heifers, even though glucose concentrations were similar in both groups (71 +/- 2.9 mg/100 ml). Concentrations of insulin after each treatment were similar in both groups and returned to pretreatment values by 60 and 120 min after injection of the low and high doses, respectively. Glucose concentrations during the first 40 min after treatment with the low dose were lower (P less than .05) in lean than obese heifers, but were similar in both groups during the first 40 to 60 min after the high dose of insulin. The high insulin dose decreased (P less than .05) glucose concentrations below those of the low dose in each group, but the difference was greater (P less than .01) in obese than lean heifers. These results indicated that obese heifers were insensitive to the glucoregulatory effects of exogenous insulin, although the maximum responses to insulin were similar.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
18.
Groesbeck CN McKinney LJ Derouchey JM Tokach MD Goodband RD Dritz SS Nelssen JL Duttlinger AW Fahrenholz AC Behnke KC 《Journal of animal science》2008,86(9):2228-2236
The objective of this study was to determine the effects of diets containing crude glycerol on pellet mill production efficiency and nursery pig growth performance. In a pilot study, increasing crude glycerol (0, 3, 6, 9, 12, and 15%) in a corn-soybean meal diet was evaluated for pellet mill production efficiency. All diets were steam conditioned to 65.5 degrees C and pelleted through a pellet mill equipped with a die that had an effective thickness of 31.8 mm and holes 3.96 mm in diameter. Each diet was replicated by manufacturing a new batch of feed 3 times. Increasing crude glycerol increased both the standard (linear and quadratic, P < 0.01) and modified (linear, P < 0.01; quadratic, P 相似文献
19.
Effects of fasting on tissue amino acid concentrations and urea-cycle enzymatic activities in young pigs 总被引：1，自引：0，他引：1
Weanling pigs were fed a 30% crude protein (CP) diet for 18 d and then assigned to one of three regimens for either 4 or 8 d: 1) fasting, 2) 3% CP, i.e., maintenance or 3) 30% CP after which they were bled, then sacrificed for tissue assessment. Relative to pigs fasted or fed 30% CP, feeding 3% CP resulted in decreased urea-N and NH3-N excretion in the urine. Arginase and ornithine transcarbamoylase (OTC) activities in liver, and arginase activity in kidney cortex were markedly lower in pigs fed 3% CP compared with those either fasted or fed 30% CP. Hepatic arginase and OTC, however, were higher in fasted pigs than in those fed 30% CP. Pigs fed 3% CP had much lower levels of free threonine, tyrosine, cystathionine, taurine and branched-chain amino acids in plasma, liver, kidney, muscle and brain than fasted pigs or those fed 30% CP. Threonine concentration in brain, liver, muscle and plasma increased as length of the fast increased. Fasted pigs had decreased free alanine levels in plasma, and decreased free serine levels in plasma and liver when compared with fed pigs. Inter-organ comparisons provided evidence that both alanine and serine were important gluconeogenic amino acids during fasting. In general, free amino acid levels in brain were similar between fasted pigs and those fed 30% CP. Fasting for 8 d caused a 10-fold elevation in urinary taurine excretion relative to that observed for 4-d fasted pigs. 相似文献
20.
The dose-dependent effects of naloxone on feed intake, and plasma chemicals (insulin, glucose, FFA) purportedly involved in feed intake regulation, were determined in 16-hr fasted sheep that were lean and chronically fed maintenance. Dorset ewes (n = 5) were treated with 0 (saline), 0.3, 1 or 3 mg/kg of naloxone in a generalized randomized block experiment with at least 7 d between successive doses. Feed intakes and plasma insulin, glucose and FFA were determined frequently during 24 hr of ad libitum intake after each naloxone treatment. The 0.3, 1 and 3 mg/kg doses of naloxone reduced (P less than 0.01) the 4-hr feed intake by 30, 40, and 60% respectively, whereas the initial feed intake (10 min) was decreased (P less than 0.05) 45% only by 3 mg/kg naloxone. However, total 24-hr intakes were similar across all doses because intakes between 4 and 24 hr of feeding in sheep treated with 0.3 (839 g), 1.0 (802 g) and 3.0 (1330 g) mg/kg naloxone exceeded (P less than 0.01) that in saline-treated sheep (391 g). Feeding-induced changes in plasma insulin, glucose and FFA concentrations were independent of naloxone treatment, suggesting that endorphinergic control of feed intake may not involve coincidental changes in plasma insulin, glucose and FFA levels which are thought to play a role in systemic regulation of appetite in animals. The endorphinergic regulation of appetite in sheep may involve the central nervous system, rather than peripheral opiate mechanisms that utilize blood-borne signals. Further, the ability of naloxone to suppress appetite in sheep appears inversely related to the duration of fasting or severity of negative energy balance. 相似文献