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Biomedical subjects

R W Rosebrough

Publications and source records attributed to R W Rosebrough.

At least 73 records · Page 4Linked to original sources
PubMed1986

Fasting and refeeding alter the insulin receptor tyrosine kinase in chicken liver but fail to affect brain insulin receptors.

Insulin receptors from chicken liver and brain were studied following alterations in the nutritional state. Chickens were either fasted for 48 h, fasted for 48 h and then refed for 24 h, or fed a regular diet ad libitum. 125I-Porcine insulin binding was significantly elevated in liver membranes from the fasted animals and lowered in refed chickens when compared to preparations from ad libitum fed chickens. These changes in 125I-insulin binding were inversely related to the levels of plasma insulin and since receptor affinities for insulin were similar in each group, they probably represent alterations in receptor number. Apparent Mr of alpha subunits of the insulin receptors was unaffected by alterations in the nutritional states. The presence of ATPase-like activities that co-eluted with liver insulin receptors from wheat germ agglutinin lectin columns but not from pea lectin columns necessitated the use of both pea and wheat germ agglutinin for liver insulin receptor purification. The insulin receptors purified from both lectin columns were recognized by anti-insulin receptor antiserum and had similar affinities for insulin which were unaltered by the nutritional state. Insulin-stimulatable autophosphorylation of the beta subunit of the insulin receptor was lower in livers from fasted chickens and intermediate in refed chickens. Furthermore, basal and insulin-induced phosphorylation of the artificial substrate poly(Glu,Tyr) 4:1 was significantly less in the fasting state and intermediate in the refed state compared to the ad libitum fed state. Insulin sensitivity (measured as the dose of insulin required for 50% maximal stimulation of kinase activity) was similar in all three states suggesting that the differences in insulin-induced phosphorylation are due to a change in maximal stimulation and not a change in insulin sensitivity. In contrast to the alterations seen with liver receptors, brain insulin receptors were unaffected by these alterations in nutritional state. These findings suggest that: liver insulin receptors are affected by altering the nutritional state; insulin binding to liver membranes is inversely related to plasma insulin levels; and tyrosine kinase is decreased both in fasted and refed animals suggesting an uncoupling of the normal interaction between alpha subunit and beta subunit in liver insulin receptors.

Animals↗
PubMed1986

Energy and protein relations in the broiler chicken. 4. Role of sex, line and substrate on in vitro lipogenesis.

Experiments were conducted with dwarf (dw) and normal lines of chickens to determine the effect of sex, diet and line on lipogenesis in the 28-day-old chick. The chicks were fed diets containing 12, 18, 23 and 30% protein. In the first experiment, in vitro lipogenesis (incorporation of [2-14C] sodium acetate into hepatic fatty acids) as well as growth from 7 to 28 days of age were determined in males and females of both lines. In the second experiment, only males and females of the dwarf line were fed to determine the relative contribution of acetate and pyruvate to in vitro lipogenesis (incorporation of either [2-14C] sodium acetate or [2-14C] pyruvate into hepatic fatty acids). Chicks of the dwarf line were smaller (P less than .01) than were those of the normal line. Females of both lines were smaller (P less than .01) than males. In vitro lipogenesis was lower (P less than .01) in the dwarf line; however, the rate for both sexes within a given line was equal. An increase in the dietary protein decreased (P less than .05) in vitro lipogenesis in both lines. The use of pyruvate as an in vitro precursor indicated that the regulation of lipid and carbohydrate metabolism may be an integrated process involving pyruvate carboxylation and subsequent flux of pyruvate carbon into either glucose or fatty acids. Based on the data presented, there is no evidence to assume, that the dwarf gene per se influences lipogenesis.

Acetates↗
PubMed1986

Effects of early feed restriction in broilers. I. Growth performance and carcass composition.

The effect of severe nutrient restriction at an early age was investigated in male and female broilers. At day 5 (females) or day 6 (males) post-hatching, chicks on limited intake were provided only enough feed (starter diet) to meet daily maintenance energy requirements only. Restriction was carried out for either 6 or 12 days, after which refeeding was on an ad libitum basis. Ad libitum fed controls were included. Minimal weight gain was noted during the period of restriction. Two weeks following refeeding, weight gains in the treated chicks exceeded that of controls. Final body weights (8 weeks) of 6-day-restricted chicks was slightly greater than controls, whereas 12-day-restricted chicks were significantly lower. Limiting nutrient intake at an early age resulted in better feed efficiency accompanied by less carcass fat and smaller abdominal fat pads. A similar, though not as dramatic effect was observed in female broilers. Results of early feed restriction on broiler growth patterns suggest that significant improvements in feed efficiency can be attained along with a reduction in total body fat.

Adipose Tissue↗
PubMed1986

Effect of early feed restriction in broilers. II. Lipid metabolism.

Three experiments were conducted with broiler chicks to evaluate the effect of dietary energy restrictions on in vitro lipid metabolism. In Experiment 1, chicks were restricted from either 6 to 12 or 6 to 18 days of age and then fed ad libitum until day 27. In Experiment 2, both male and female chicks were restricted from 5 to 11 days of age and then were refed until 27 or 54 days of age. Glutamic:oxaloacetic aminotransferase (GOT), isocitrate dehydrogenase (ICD), malic enzyme (ME) and the fatty acid synthetase complex (FAS) were assayed at 27 days (Experiment 1) and at 27 and 54 days (Experiment 2). In Experiment 3, male chicks were restricted from days 6 to 12 and then were refed until day 27. In vitro lipogenesis and enzyme activities were determined during the 12 to 18-day period as the chicks were refed following the restriction. Both restriction regimes decreased (P less than .05) ME and FAS at the conclusion of the respective restriction intervals (Experiments 1 & 2). The 6 to 12-day restriction decreased (P less than .05) in vitro lipogenesis in the 12 day old chick when compared to controls. When restricted chicks were refed, in vitro lipogenesis exceeded that of the controls at both 14 and 16 days, but was less than that of the controls at 27 days.

Adipose Tissue↗
PubMed1985

Endocrine adaptations of periparturient swine to alteration of dietary energy source.

Lipid compared with carbohydrate calories in the diet of peripartal sows was examined for specific metabolic effects. Blood samples from second-parity Yorkshire sows fed isocaloric-isonitrogenous diets that differed by either glucose or corn oil supplying 20% of the daily metabolizable energy intake were assayed for growth hormone (GH), insulin and prolactin (PRL) concentrations. On d 97 to 103 of gestation, serum GH levels were reduced following feed intake; the reduction was greater (P less than .05) in glucose-fed sows during the postprandial period. Insulin concentration was increased following consumption of either diet, but to a greater (P less than .05) extent in glucose-fed sows corresponding to the greater (P less than .05) blood glucose response. Basal, fasting concentrations of PRL were not affected by dietary energy source; however, thyrotropin-releasing hormone (TRH) infusion resulted in a greater (P less than .05) PRL response of fat-fed sows. Samples obtained on d 8 to 11 of lactation revealed that TRH stimulated (P less than .05) GH secretion and the response was greater (P less than .05) in fat-fed sows. Plasma insulin concentration was increased (P less than .05) following feeding, and the increase was greater (P less than .05) in glucose-fed sows. Similar to the response measured in gestating sows, TRH-induced increases in PRL was greater in fat-fed, lactating sows. Sham-nursing did not influence maternal PRL concentration compared with the immediate increase noted following natural nursing. No effect of dietary energy source on reproductive performance characteristics was noted. Results of this study have shown that dietary lipid, compared with carbohydrate, selectively increased the sensitivity of the pituitary gland to a GH and PRL secretagogue such as TRH. The beneficial effects of lipid in the diet of peripartal swine may be attributable, in part, to the effect of dietary lipid on maternal pituitary PRL synthesis and(or) release.

Adaptation, Physiological↗
PubMed1985

Digestibility of fiber components and reproductive performance of sows fed high levels of alfalfa meal.

Two experiments were conducted with second-parity sows fed either 5 or 50% alfalfa meal diets (Exp. 1) or 5, 50 or 95% alfalfa meal diets (Exp. 2) beginning 30 d after breeding and continuing through lactation, 21 d postpartum. Diets in both experiments were calculated to be equal in crude protein, but different in metabolizable energy content. Feed intake was restricted to 2 kg/d during gestation and ad libitum during lactation. Sows were tethered in metabolism crates 45 d after breeding. Total feces were collected during two 5-d collection periods, 60 and 100 d after breeding. Digestibilities of dry matter, fiber components (neutral detergent fiber, acid detergent fiber, hemicellulose and cellulose), protein and energy were determined in both experiments for all diets and periods of gestation. In both experiments, there was a reduction (P less than .05) in digestibility of dry matter, fiber components, protein and energy with increasing fiber levels for both periods of gestation. In Exp. 1, the decrease in digestibility of dry matter, neutral detergent fiber, acid detergent fiber, cellulose and energy was greater at 100 d gestation than at 60 d in sows fed 50% alfalfa. In Exp. 2, 50 and 95% dietary alfalfa reduced 60-d digestibilities of dry matter, all fiber constituents, energy and protein; these digestibilities were further reduced (P less than .05) at 100 d of gestation. In Exp. 1, weight gains of sows fed 5 and 50% alfalfa diets from breeding to 109 d gestation, were 42 and 18 kg/sow (5 greater than 50% level, P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1985

Energy and protein relationships in the broiler. 1. Effect of protein levels and feeding regimens on growth, body composition, and in vitro lipogenesis of broiler chicks.

Male broiler chicks were fed ad libitum diets containing 18, 23, or 30% protein for 3 weeks. In addition, chicks were fed diets containing 12, 23, or 30% protein on a 3-day rotation. Finally, chicks were fed either the 23 or 30% protein on a schedule of 2 days on feed and 1 day off feed. These feeding schemes allowed chicks to consume low to excess protein coupled with either adequate or inadequate energy intake. Feed intakes were equal for the 18, 23, and rotational percent protein dietary groups and lower (P less than .05) for the 30% ad libitum group. Chicks fed the 18% protein diet ad libitum were the least efficient (P less than .05) at utilizing feed and the most efficient (P less than .05) at utilizing protein for weight gain. Compared to the ad libitum situation, restricted feeding improved feed and protein efficiency of chicks fed 30% protein diets but not of chicks fed 23% protein diets. Body composition data on a dry matter basis supported a positive relationship between dietary protein and percent lean tissue. Conversely, expressing data on a whole bird basis indicated that lean body mass was favored by feeding the diet containing 23% protein. In vitro lipogenesis was greatest (P less than .05) in chicks fed a 18% protein diet ad libitum and least (P less than .05) in chicks fed a 30% protein diets ad libitum.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Effect of dietary fat and environment on lipogenesis by large white breeder turkeys.

An experiment was conducted to evaluate the effects of either a low-fat (8% of total calories) or high-fat (47% of total calories) diet on Large White breeder females maintained at a constant (21 C) or a cyclic temperature regimen (12 to 27 C). Each diet was fed to 32 hens individually caged in the cyclic condition and 46 in the constant condition. Energy consumption, reproductive performance, and in vitro lipogenesis were monitored for hens subjected to both temperature and dietary treatments. Hens consumed more (P less than .05) dietary energy when maintained at a constant temperature or when fed the low-fat diet. Hens also produced more (P less than .05) eggs when maintained under cyclic temperature conditions, although this observation was tempered by the fact that fewer hens were broody. More (P less than .05) of the fertile eggs from hens held at the cyclic temperature resulted in live poults. The high-fat diet decreased (P less than .05) in vitro lipogenesis in hens and may also decrease the maintenance energy requirement by providing a preformed fatty acid pool for egg lipids. The high-fat also decreased (P less than .05) liver lipid and the activities of fatty acid synthetase and malic enzyme.

Animals↗
PubMed1985

Energy and protein relations in the broiler chicken. 2. Effect of varied protein and constant carbohydrate levels on body composition and lipid metabolism.

Male broiler chicks were fed diets containing 18, 23 or 30% protein on an ad libitum basis for 3 weeks. Chicks were also fed these diets on a restriction regime consisting of seven 3-day cycles (2 days with and 1 day without feed). Another group of chicks were fed diets containing 12, 23 or 30% protein on a 3-day rotation consisting of a daily change in dietary protein. Ad libitum. Feed intakes of chicks were inversely (P less than .05) related to the level of the dietary protein. Body composition data seemed to support a positive (P less than .05) relationship between dietary protein and total carcass protein and an inverse (P less than .05) relationship between dietary protein and carcass fat. In vitro lipogenesis was greater (P less than .05) in chicks fed an 18% protein diet than in chicks fed either 23 or 30% protein diets. Restricted. Protein levels had no effect on lipogenesis in chicks fed on a restriction regime but regulated lipogenesis in chicks fed on the rotational regime. Fatty acid synthetase, malic enzyme and isocitrate dehydrogenase activities, when measured during the rotational regime, were greatest following the 12% diet and least following the 30% diet. Enzyme activities, determined during the restriction regime, were greatest (P less than .05) after 1 day of refeeding and least (P less than .05) after 1 day of feed withdrawal. Measurement of net glucose production in vitro indicated that high-protein diets and feed withdrawal stimulated production of glucose.

Animals↗
PubMed1985

Protein and energy relations in the broiler. 3. Growth and in vitro lipid metabolism in male and female chickens used as parent stock.

Growth and in vitro metabolism were assessed in 4 wk-old Ross male and Vedette dwarf female chickens and the offspring of this mating. Chicks were fed diets formulated to contain the same carbohydrate energy level (56% of total metabolizable energy) but different levels of protein (12, 18, 23 and 30%) for 21 days beginning when they were 7 days of age. Dietary regimes were devised to study the role of protein per se in the regulation of growth and in vitro lipogenesis. Dietary protein had little effect on dwarf female growth. Males receiving the diet containing 30% protein and fed ad libitum grew at a slower (P less than .05) rate than did males receiving the 18 or 23% protein diets. A 3-day rotational feeding regime that consisted of three different levels of dietary protein (12, 23 and 30%) did not adversely affect the growth of either males or females when compared to the effect of feeding a 23% protein diet ad libitum. Intermittent feeding decreased (P less than .05) feed consumption and weight gain of both sexes. In vitro hepatic lipogenesis in both males and females was inversely related to the level of protein in the diet being fed; however, the overall lipogenic rate for males was greater (P less than .05) than that for females. Certain liver enzyme activities were also inversely related to the level of dietary protein and the analysis of data suggested that both reducing equivalent (NADPH) production and the malate-alpha ketoglutorate shuttle were also related to dietary protein status.

Animal Husbandry↗
PubMed1985

Effect of dietary energy on lipogenesis in turkey hens prior to and after sexual maturity.

An experiment was conducted with 208 Diamond Hybrid Small White turkey hens to determine the role of dietary energy on in vitro lipid metabolism. Young turkey hens were fed diets containing either a high (3100 kcal metabolizable energy) or low (2400 kcal metabolizable energy) energy level from 12 to 30 weeks of age. Both diets contained 12% protein and were fed on an ad libitum basis. Hens were then maintained under a constant (21 degrees C) or cyclic (12 to 27 degrees C) daily temperature regime and fed either a high (47% of the total energy) or low (8% of the total energy) fat diet for a 100-day egg collection period. Hens were killed at the end of the growing phase, after 1 week of receiving the breeder diets and after 2 weeks of stimulatory light (14 hr/day). Hens were also killed following a 100-day egg collection period. In vitro lipid metabolism and enzyme activities were determined at these periods. In vitro fatty acid synthesis was greater (P less than .05) in hens fed the high-energy prebreeder diet although total energy intakes for both groups of birds were similar. Transferring both groups of hens to individual cages in the breeder house decreased (P less than .05) fatty acid synthesis; however, lipogenic rates were higher (P less than .05) after 2 and 18 weeks of stimulatory light. The high-fat diet decreased (P less than .05) in vitro lipogenesis, fatty acid synthesis, malic enzyme and esterification of palmitate. Acetate utilization in the presence of pyruvate was one-half the rate in the absence. Diets fed prior to sexual maturity did not affect egg production or in vitro lipogenesis of mature hens.

Animals↗
PubMed1984

Fetal hepatic and neural substrate utilization as affected by induced nutritional ketosis in swine.

Systemic ketosis was induced in first-parity gilts by the isocaloric substitution of glucose with 1,3-butylene glycol to supply 20% of the total dietary energy beginning on d 23 (23 BG) or d 60 (60 BG) of gestation. Ketosis reduced (P less than .05) maternal plasma glucose, urea N and insulin concentrations. Fetal carcass dry matter and carcass glycogen contents were reduced (P less than .05) by maternal ketogenic calorie substitution, whereas fetal hepatic glycogen and lipid contents were not influenced by maternal treatment. Neural acetate oxidation was reduced (P less than .05) in the 23 BG and 60 BG fetuses, with a concurrent increase (P less than .05) in beta-hydroxybutyrate (BOHB) oxidation. Neural lipogenesis measured from acetate and BOHB substrates was nominal in the d 105 pig fetus. Fetal hepatic acetate and BOHB utilization for lipogenesis were increased (P less than .05) by maternal ketosis. Reproductive performance characteristics (litter size, number stillborn and birth weight) were not improved by maternal ketosis. The substantial improvement in lactation weight gain by litters from 23 BG and 60 BG dams (20%, P less than .05) may suggest a carryover effect of gestation dietary treatment on lactation performance.

3-Hydroxybutyric Acid↗
PubMed1984

Studies on blood calcium relationships in the turkey.

Studies were conducted to establish normal ionized calcium levels and the relationship of ionized calcium to total blood calcium concentrations during various physiological states in the turkey. Ionized calcium levels were similar in fresh plasma and serum. Ionized calcium in plasma was significantly lower after 8 hr of storage at 4 C compared to fresh plasma. After only 4 hr of storage ionized calcium levels were significantly depressed in serum. Significant changes were noted in both plasma and serum ionized calcium when stored frozen or unfrozen for 24 hr. Several anticoagulants were tested for interference with plasma free calcium. Sodium heparin, 10 U/ml, was found to be the most suitable. In the poult, plasma ionized calcium was 35% of total calcium and was influenced by a withholding food and refeeding regimen. Absolute ionized calcium concentrations were greater in the blood plasma of adult hen but comprised a smaller proportion of total calcium (12 to 24%) compared to poults or age-matched males. It is apparent from the results of this study that dramatic changes in total blood calcium concentrations do not result in similar magnitude fluctuations of ionized calcium concentrations; however, the relationships of ionized to total calcium would be the best index to relate calcium homeostasis and physiological state.

Animals↗
PubMed1984

Effect of starvation-refeeding and an exogenous glucocorticoid on carbohydrate metabolism in chick liver.

Broiler chicks, 4 weeks of age, were subjected to a regimen of 48-hr starvation and 24-hr refeeding as a means of inducing hepatic glycogen supercompensation. A synthetic glucocorticoid (prednisolone) and transcription inhibitor (actinomycin D) treatment were superimposed on the starvation-refeeding regimen to examine the effect of an exogenous glucocorticoid and the necessity for de novo protein synthesis during glycogen supercompensation. Starvation decreased plasma glucose, immunoreactive insulin and liver glycogen. These parameters returned to, or overshot prefasting levels after a 48-hr refeeding period. Prednisolone magnified the overshoot response but some de novo protein synthesis was required. Glycogen synthase a activity was opposite that of liver glycogen content. A possible nonhormone stimulated glycogen synthetic mechanism in the starvation-refeeding response of the chick was noted.

Animals↗
PubMed1983

Role of protein and energy in the regulation of energy metabolism and reproductive performance of large white turkey hens.

An experiment was conducted with Nicholas Large White turkey hens to determine the roles of energy and protein in energy efficiency, reproductive performance, and in vitro metabolism. Hens were fed diets containing 2400 or 2850 kcal ME/kg and either 12 or 17% protein. The experiment was conducted in environmentally controlled rooms maintained at 21 C and 50% dew point. The efficiency of energy utilization for both egg and poult production was greater in the 2400 kcal diets, and the efficiency of protein utilization was greater in the 12% protein diets. In vitro lipogenesis was less and plasma uric acid was greater (P less than .05) in hens fed diets containing 17% protein. In contrast, plasma phosphorous and calcium were greater (P less than .05) in hens fed diets containing 2400 kcal ME/kg. Plasma zinc and copper were unaffected by either dietary energy or protein levels. Because the 2400 kcal diets contained 30% wheat middlings, the higher metal levels observed in hens may be related to some component in middlings. Broodiness and mortality were also lower (P less than .05) in the groups fed diets containing 2400 kcal ME/kg.

Animals↗
PubMed1983

Effect of protein level and supplemental lysine on growth and urea cycle enzyme activity in the pig.

Two experiments were conducted with young, growing pigs to evaluate the effects of protein levels and supplemental lysine on growth, body characteristics and urea cycle enzyme activities. In the first experiment, 8-week-old pigs weighing 17 kg were fed two levels of protein (12 or 20%) until they reached slaughter weight of approximately 95 kg. In the second experiment, three levels of protein (12, 18 or 24%) and one level of additional lysine (9 g/kg of diet added to the 12% protein diet) were fed for the same interval. After slaughter, urea cycle enzyme activities (argininosuccinate synthetase, EC 6.3.4.5; argininosuccinate lyase, EC 4.3.2.1; and arginase, EC 3.5.3.1) were determined in liver homogenates. Early growth of pigs was improved by increasing the protein level (12%) but not by adding the limiting amino acid lysine to the 12% diet. The cross sectional area of the Longissimus dorsi muscle at slaughter was increased by protein level (12%) or by adding lysine to the 12% protein diet. In contrast, subcutaneous fat was decreased only by increasing the dietary protein level. The activities of arginase, argininosuccinate synthetase and argininosuccinate lyase were increased in a linear fashion by increasing the dietary protein level. In contrast, adding lysine to the 12% protein diet did not increase urea cycle enzyme activities.

Adipose Tissue↗
PubMed1982

Effects of dietary 1,3-butylene glycol on adipose tissue metabolism from lean and obese swine.

One,three-butylene glycol (BG) was isocalorically substituted for glucose and fed ad libitum to lean (XB) and obese (HL) swine at 0, 10, and 20% of the total dietary ME from 25 kg body weight until slaughter at 90 kg. BG depressed rate and efficiency of gain in both groups. Plasma beta-hydroxybutyrate concentration was increased by the ketogenic energy substitution. Plasma glucose and free fatty acids were not influenced by diet composition. Adipose tissue utilization of glucose for lipogenesis was depressed by BG in both XB and HL animals after 4 wk of treatment. Insulin added in vitro increased glucose utilization by approximately 20% in adipose tissue from both breed groups; however, the BG induced depression of glucose utilization for fatty acid synthesis was still evident. Insulin-stimulated glucose utilization was greater in XB then in L swine. After 12 wk of dietary treatment, animals given BG had significantly increased plasma insulin concentration and decreased plasma urea concentrations. Although the absolute rates of lipogenesis had decreased after 12 wk of treatment, similar diet-related results were obtained. Insulin did not stimulate glucose utilization by adipose tissue from animals of either breed group at this latter sampling. Fatty acid esterification was slightly depressed by BG at the 4 wk sampling, but after 12 wk of treatment, only a significantly breed group effect was evident. Subcutaneous fat thickness, loineye area and carcass percentage lean cuts were not influenced by diet composition. This experiment demonstrated that ketogenic energy and substitution in the diet does depress the rate of de novo lipogenesis from glucose as measured by in vitro incubation of swine adipose tissue. Supplementation of the incubation media with massive quantities of insulin did not reverse the dietary treatment effects, and animals of both lean and obese phenotypes responded similarly to the dietary treatment. The absence of dietary treatment effects on indices of body fat content suggest that ketone bodies may be substituted for glucose as a lipogenic substrate in swine.

3-Hydroxybutyric Acid↗