Effects of dietary carbohydrate, fat and protein on growth, body composition and blood metabolite levels in the dog

Six semipurified canned diets ranging in composition from 0 to 62% of energy from carbohydrate and from 20% to 48% of energy from protein were fed to female beagle dogs for 8 months. Additionally, three commercial-type diets were also fed. The effects of these diets on growth, body composition and selected blood metabolite levels in the dogs were studied. The dogs readily consumed each of the nine diets fed. The level of carbohydrate, fat or protein in the diet did not influence body weight gain during the first 16 weeks nor was nitrogen balance affected by the diets. At the end of the 32-week study, dogs fed the high-carbohydrate (62% of energy) diet contained less body fat but an equal-free mass, than did dogs fed lower-carbohydrate (20--42% of energy) diets with a similar quantity of protein. Consumption of carbohydrate-free diets did not influence postprandial levels of circulating glucose or insulin in the dogs. Plasma cholesterol levels were elevated in dogs consuming in the diets high in fat but plasma triglyceride levels were not influenced by the diets fed. Consumption of high-protein (46--48% of energy) diets elevated plasma urea nitrogen levels but had minimal influence on plasma amino acid levels. The general response of these young dogs was not markedly influenced by consumption of diets ranging from carbohydrate-free to high-carbohydrate and from adequate-protein to high-protein.     

Use of urea by early postpartum Holstein cows

Thirty-nine lactating Holstein cows were fed high-energy complete rations ad libitum with crude protein: 1) 11.7% (negative control); 2) 13.9% (1% urea); 3) 16.6% (1% urea); or 4) 16.6% (positive control) in a continuous 12-wk study beginning at wk 5 postpartum. Milk production of 27.7, 31.8, 34.0, and 30.4 kg/day showed the use of urea nitrogen by groups 2 and probably 3. Two digestion-nitrogen balance trials with each cow also provided evidence that urea nitrogen was used for milk secretion. Energy digestibility averaged 59.4, 64.2, 65.4, and 65.8; and lower for the negative control diet. Nitrogen solubility in the diets was 28, 36, 32, and 21%, which reflects the objective of selecting ingredients with low nitrogen solubility for use in urea diets. Concentrations of ammonia nitrogen before and after feeding were 1.1, 3.3, 3.5, 4.2, and 2.2, 11.2, 11.9, and 9.3 mg/100 ml of rumen fluid. The prefeeding amounts were probably too low for maximum microbial growth. Urea-nitrogen concentrations in plasma were 8.65, 10.32, 18.00, and 17.03 mg/100 ml. These results lend support to the postulate that lactating cows in early lactation can use urea nitrogen when high-energy complete rations with ingredients of low nitrogen solubility are fed ad libitum.     

The role of neuroticism in daily stress and coping.

The authors examined the influence of neuroticism (N) on the occurrence of different types of daily events, primary and secondary appraisals of those events, use of specific coping strategies, and end-of-day negative mood. College students completed questionnaires at the end of every day for 14 consecutive days. When reporting their most stressful event of each day, high-N individuals, compared with low-N individuals, reported more interpersonal stressors and had more negative primary and secondary appraisals and reacted with more distress in response to increasingly negative primary and secondary appraisals. Compared with low-N individuals, high-N individuals used less-adaptive coping strategies (e.g., hostile reaction) and reacted with more distress in response to some types of coping strategies. The appraisal findings, in particular, help to explain the chronic negative affectivity associated with neuroticism. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of dietary protein or amino acids in the perfusion medium on amino acid metabolism in perfused adult rat liver

To elucidate the response of amino acid metabolism in the liver to dietary protein and plasma amino acids, the livers of adult rats fed on diet containing 10% (control) or 3% (low-protein) egg protein for 3 weeks were perfused for 120 min with amino acid-free medium in Experiment 1 or medium containing an amino acid mixture simulating that in plasma in Experiment 2. During perfusion about 40% of the free amino acids were lost from the liver in Exp. 1, and about 30% in Exp. 2. During this period, in Exp. 1 the releases of free amino acids and urea into the medium were 140 mumol and 2.52 mg, respectively, in the control group and 207 mumol and 1.10 mg respectively, in the low-protein group. Thus release was greater than decrease in free amino acids in the liver. Essential amino acids, particularly lysine and branched chain amino acids, were released preferentially. The results suggest that the amount of breakdown of liver protein in the two groups was similar, but that the nitrogen was mainly released as free amino acids in the low-protein group, and as urea in the control group. On the contrary, in Exp. 2 the amount of nitrogen released from the liver was comparable to the decrease in amino acids in the liver, and the releases of urea were also less, being 1.83 mg in the control group and 0.54 mg in low-protein group. The results show that amino acid metabolism in the liver is greatly affected by the nutritional state of the animal and the amino acid content of the perfusion fluid.     

Dietary protein, urea nitrogen appearance and total nitrogen appearance in chronic renal failure and CAPD patients

This study was carried out to examine the mathematical relationships between the urea nitrogen appearance (UNA), total nitrogen appearance (TNA) and dietary nitrogen intake (DNI) in patients with chronic renal failure. Studies were conducted in 20 nondialyzed patients with advanced chronic renal failure (CRF) who were fed 27 constant protein diets for 24.8 +/- 9.5 days (SD) and eight patients undergoing continuous ambulatory peritoneal dialysis (CAPD), who ingested 13 constant protein diets for 20.3 +/- 4.9 days. All patients lived in a hospital research ward throughout the study and underwent full nitrogen balance measurements. Data were analyzed after patients attained equilibrium or near equilibrium with each dietary protein intake. In the CRF patients, using the mean values obtained during the equilibrium phase, there was a direct and precise correlation between the TNA and UNA, where TNA g/day = 1.19 UNA g/day + 1.27 g/day, r = 0.948. The correlation between DNI and UNA was also highly significant, but less precise, with somewhat greater 95% confidence intervals: DNI g/day = 1.20 UNA g/day + 1.74 g/day, r = 0.865. The relationship between DNI and TNA was not much more precise: DNI g/day = 0.97 TNA g/day + 0.65 g/day, r = 0.880. With the CAPD patients, the relationships were as follows: TNA g/day = 0.94 UNA g/day + 5.54 g/day, r = 0.956; DNI g/day = 0.97 UNA g/day + 6.80 g/day, r = 0.705; DNI g/day = 1.07 TNA g/day + 0.63 g/day, r = 0.760. For the CAPD patients, the lowest 95% confidence intervals were also found for the correlation between TNA and UNA. Thus, in both CRF and CAPD patients, the TNA is highly and precisely correlated with the UNA. The DNI is also significantly correlated with UNA and TNA, but the relationship is less precise. In both of these two groups of patients, the difference between the regression equations for TNA versus UNA and DNI versus UNA was, to a substantial degree, accounted for by the intercept.     

Effect of Rolling and Subsequent Annealing on Microstructure,Microtexture, and Properties of an Experimental Duplex Stainless Steel

A lean duplex stainless steel (LDSS) has been prepared with low-N content and processed by different thermo-mechanical schedules, similar to the industrial processing that comprised hot-rolling, cold-rolling, and annealing treatments. The microstructure developed in the present study on low-N LDSS has been compared to that of high-N LDSS as reported in the literature. As N is an austenite stabilizer, lower-N content reduced the stability of austenite and the austenite content in low-N LDSS with respect to the conventional LDSS. Due to low stability of austenite in low-N LDSS, cold rolling resulted in strain-induced martensitic transformation and the reversion of martensite to austenite during subsequent annealing contributed to significant grain refinement within the austenite regions. δ-ferrite grains in low-N LDSS, on the other hand, are refined by extended recovery mechanism. Initial solidification texture (mainly cube texture) within the δ-ferrite region finally converted into gamma-fiber texture after cold rolling and annealing. Although MS-brass component dominated the austenite texture in low-N LDSS after hot rolling and cold rolling, that even transformed into alpha-fiber texture after the final annealing. Due to the significant grain refinement and formation of beneficial texture within both austenite and ferrite, good combination of strength and ductility has been achieved in cold-rolled and annealed sample of low-N LDSS steel.     

Nitrogen and fat balances in very low birth weight infants fed human milk fortified with human milk or bovine milk protein

The study was designed to compare two different human milk fortifiers in a group of very low birth weight (VLBW) infants by analysing nitrogen and fat balances, serum concentrations of alpha-amino-nitrogen, urea, and prealbumin as well as growth rates when human milk enriched with one of the two studied fortifiers was fed to the infants. Fortifier A contained different bovine proteins, peptides and amino acids and had an amino acid composition comparable to that of the nutritional available proteins in human milk, with carbohydrates, and minerals. Fortifier B was composed of freeze-dried skimmed human milk and minerals to achieve a similar macronutrient composition in both fortifiers. Eleven infants were fed with human milk enriched with fortifier A and 13 with fortifier B. After a 10-day equilibration period, a 3-day metabolic balance was performed. On the 14th day of the study blood was obtained preprandially for serum analysis and growth rates were estimated. The nitrogen absorption rate (93.8% vs 93.5%) as well as the retention rate (80.8% vs 78.5%) were no different between the groups. The fat absorption rate (92.3% vs 91.5%) as well as the weight gain (32.1 vs 31.1 g/day) were similar and there were no differences in the serum parameters studied. The results indicate that feeding VLBW infants with human milk enriched with a well-balanced bovine fortifier fulfil their nutritional requirements as well as diets composed exclusively of human milk protein.     

Special Committee on HIV discusses AIDS, Committee goals

Intraperitoneal glucose tolerance tests were performed at 4-week intervals in groups of weanling rats before and after feeding with maize- or cassava-based diets with and without adequate protein and sublethal cyanide supplementation. Weaning weights were doubled (increase of about 50 g) after 4 weeks on control (maize-based with adequate protein) and protein-replete diets. Weight gain on the protein-deficient diets was much less (22 g or 50%), a pattern maintained by the rats on these diets until the age of 12 weeks. Plasma thiocyanate levels were identical at weaning and after 8 weeks of the control diet but increased by 200-300% after 4 weeks intake of the cassava or cyanide-supplemented feeds. Levels returned to normal in all groups after a further 4 weeks feeding with the control diet. Glucose tolerance (as assessed by the area under the 2 h glucose v. time curve) was impaired to a varying extent in the rats after 4 weeks on the various diets: protein-replete cassava and protein-deficient maize diets by 50% protein-deficient cassava diet by 300%, and cyanide-supplemented protein-deficient maize diet by 150%. The derangement in the rats on the protein-replete cassava diet was unaffected by a further 4 weeks intake of the control diet, unlike in the other groups where there was significant improvement in the glucose tolerance indices at the same time. It is concluded that in growing rats: (1) cassava intake and protein malnutrition may have independent and additive effects on the genesis of glucose intolerance, (2) cyanide supplementation of a cassava-free protein-replete diet has no effect on glucose tolerance.     

Paradoxical positive nitrogen balance in burn patients receiving high-dose administration of insulin for nutritional care

BACKGROUND: Nitrogen balance in patients who need high-dose administration of insulin has not been evaluated clinically. The purpose of this study was to compare the difference in nitrogen balance between burn patients who received high-dose administration of insulin and those who did not. METHODS: This study was performed in 19 severely burned adults with no liver or kidney failure. Patients were divided into two groups on the basis of the mean ratio of administered insulin and calorie intake (I/C) for the initial 4 weeks, a high I/C group (n = 9) and a low I/C group (n = 10). There were no significant differences between the two groups regarding age, percentage of area burned, and body weight. Nitrogen balance, blood urea nitrogen, and urine urea nitrogen were measured in all patients. Plasma concentrations of glucose, insulin, glucagon, cortisol, and urinary excretion of 3-methyl-histidine were measured in 12 patients (six in each group). RESULTS: Until day 10 both groups exhibited similar changes in plasma concentrations of glucose, insulin, glucagon, and cortisol. Subsequently, plasma concentrations of insulin and glucagon began to decrease in the low I/C group, whereas a high level was sustained in the high I/C group (p < 0.05). Plasma glucose and cortisol measurements showed no significant differences between the two groups. Blood urea nitrogen levels and urinary excretion of 3-methyl-histidine were not different between the two groups. Urine urea nitrogen excretion in the high I/C group, however, was significantly lower than that in the low I/C group from day 8 (p < 0.05). Thus the high I/C group achieved positive nitrogen balance more quickly than the low I/C group. Paradoxically, however, the high I/C group was at higher risk of septic complications and exhibited higher mortality than the low I/C group (p < 0.05). CONCLUSIONS: These results indicate that an improvement in nitrogen balance, which is accepted as a good thing in the management of critically ill patients, is not necessarily good in the high I/C group and that residual nitrogen was retained within the body in the high I/C group.     

Dietary niacin deficiency lowers tissue poly(ADP-ribose) and NAD+ concentrations in Fischer-344 rats

Poly(ADP-ribose) is synthesized in response to DNA strand breaks, using NAD+ as substrate, and has been implicated in the process of DNA repair. Because NAD+ can be synthesized from niacin or tryptophan, both of these components must be manipulated to alter niacin status. Six dietary treatments were used, including niacin-deficient (ND) diets and niacin-replete (NR) diets consumed ad libitum and the NR diets pair-fed (PF) to the ND intake. The ND, NR and PF diets contained either 80 g casein + 50 g gelatin/kg diet (8-5 diets) or 70 g casein + 60 g gelatin/kg diet (7-6 diets) to control tryptophan content. The 8-5ND and 7-6ND diets induced mild and severe symptoms of niacin deficiency, respectively, over a 3-wk period in male weanling Fischer-344 rats. Food intake and weight gain were suppressed in both of the ND groups compared with their respective NR controls. Weight gain was not different between ND animals and their PF counterparts. At 3 wk, blood, liver, kidney, heart and lung NAD+ concentrations for both 8-5ND and 7-6ND animals were all significantly lower than those for their respective PF groups. In the groups fed the 8-5 diets, liver poly(ADP-ribose) was lower in the ND group (64% of PF), with no difference between the NR and PF groups. In rats fed the 7-6 diets, poly(ADP-ribose) levels were further decreased in the ND group (43% of PF), but food restriction also exerted an independent effect (PF levels were 46% of NR levels).(ABSTRACT TRUNCATED AT 250 WORDS)     

Differential effects of protein restriction on gamma-glutamyltranspeptidase [EC 2.3.2.2] activity in young and mature rats

Gamma-glutamyltranspeptidase (GGT, EC 2.3.2.2) activity was determined in the plasma and liver of 40 young (50 days old) and 40 mature (300 days old) male Wistar rats, after a protein restriction period of 28 days. Casein protein levels used were: 1%, 3%, 5%, 7% and 28% (control). Weanling rats submitted to protein-free diet and adult rats submitted to that and other low-protein diets (1%, 3% or 5% casein) presented weight reductions (-0.38 +/- 0.07 g/day and -0.98 +/- 0.19 g/day, respectively). Only in young animals did these weight reductions parallel those of food consumption (37 +/- 12% of control), plasma protein (52 +/- 11% of control), plasma albumin (70 +/- 12% of control), hepatic RNA (68 +/- 7% of control) and protein (71 +/- 8% of control). A marked effect of the protein restriction, increasing the GGT activity, was also observed only in young rats. A significant (P < 0.05) rise was promoted by the protein-free diet in the plasma GGT (2.83 +/- 1.39 vs 0.69 +/- 0.50 mU/ml for control) and by both the protein-free and 3% casein diets, in the liver GGT (respectively, 16.00 +/- 6.72 and 7.75 +/- 3.49 vs 0.94 +/- 0.57 U/g protein for control). The different results obtained for young in relation to mature animals could be explained by the reduction of both protein and sulfur-containing amino acid requirements with aging.     

Surgical management of retinal detachments related to coloboma of the choroid

We examined the influence of extruded chickpeas and wheat relative to casein and wheat in a dimethylhydrazine (DMH)-induced colon tumor study in male Sprague-Dawley rats. The three diets, based on a modified AIN76 rodent diet with fat present at 10 g/100 g dry matter (DM), were as follows: casein with wheat starch (Cas/S) as control, casein with wheat (Cas/W) and chickpeas with wheat (CP/W). All diets were fed from 5 wk of age throughout the 28-wk study. At 28 wk, there was a significantly lower incidence of large intestinal tumors in rats fed Cas/W relative to those fed CP/W ( 11 vs. 56%, chi-square test, P = 0.018). The colonic tumor burden (tumors/tumor-bearing animal) was not different in Cas/W-fed and CP/W-fed rats (1 vs. 1.7), but the tumor mass index was significantly lower in the former group (0.22 vs. 1.21, P = 0.026). Rats fed the CP/W diet had significantly lower plasma cholesterol concentration (P < 0.01) than rats fed the other two diets. The cecal contents of rats fed the CP/W diet had significantly greater relative weights (46%, P < 0.05) than those of the Cas/W-fed rats; this was associated with higher concentrations of all short-chain fatty acids. Fecal analyses showed significantly (P < 0.05) higher concentrations of total fat (54%), total steroids (83%) and secondary bile acids (179%) in the CP/W-fed rats relative those fed Cas/W. There were higher concentrations of nitrogen in the feces of CP/W rats relative to the Cas/W-fed rats (84%, P < 0.05), associated with greater fecal weights (67%, P < 0.05). Although wheat and its fibers have been shown to be protective against DMH-induced cancers in rats, this was not the case in this study in which chickpeas (45 g/100 g diet) provided the protein and were an important source of soluble fiber. Elevated fat, secondary bile acid concentrations and/or nitrogenous compounds could be responsible for the increased colon tumorigenesis seen and may reflect a legume effect.     

Use of synthetic oligonucleotides for inhibition of factor NF-kappa B

The effect of the proportion of clover in the diet (200, 500 or 800 g/kg total dry matter (DM) on milk production of cows housed indoors and fed on a mixture of perennial rye-grass and white clover was measured in mid (Expt I) and late (Expt II) lactation. Higher clover contents increased the nutritive value of the diets, resulting in increased energy and protein intakes. DM intakes of cows offered 500 or 800 g clover/kg DM diets ad lib. (Expt I and Expt II, Period 1) were not significantly different but were 11-17% greater (P < 0.05) than intakes of cows fed on 200 g clover/kg total DM diets. Cows offered restricted allowances (Expt II, Period 2) had similar intakes irrespective of diet. In Expt I cows fed on 500 or 800 g clover/kg DM diets ad lib. produced 30 or 33% respectively more milk (P < 0.05) than cows fed on 200 g clover/kg total DM diets. During Expt II, Period 1, cows fed on 500 or 800 g clover/kg DM diets ad lib. produced 18 or 16% more milk (P < 0.05) respectively than cows given 200 g clover/kg total DM diets. In both these experiments the increased milk yields were due to increased intake and the higher nutritive value of the high clover diets. There was no difference in the feed conversion efficiencies of cows if maintenance energy requirements were taken into account. However, cows on restricted allowances (Expt II, Period 2) showed no significant difference in milk yield, indicating that the effect of increased nutritive value was very slight. There were no consistent effects on milk fat, protein or lactose concentrations. Concentrations of blood and milk urea increased as the clover content of the diet increased (Expt 1 only), and this was associated with increased milk non-protein N and a decreased ratio of casein N: total N. Both trials indicated an optimum clover content in the diet for milk production of 600-700 g/kg total DM.     

The influence of diflubenzuron on several weight characteristics in growing male broiler and layer chickens

Diflubenzuron (Dimilin, TH-6040; N-[[(4-chlorophenyl)-amino] carbonyl]-2,6-difluorobenzamide) was fed to male broiler and layer chickens at levels of 0, 2.5, 25, and 250 ppm from 1 day to 98 days of age. Characteristics measured were body weights, grams of feed per gram of body weight, testes weights, liver weights, comb weights, and feet weights. There were no consistent significant differences among the control, 2.5, 25, or 250 ppm groups in any of the characteristics measured. There was a trend for higher body weights in the chickens fed diets containing diflubenzuron.     

Gender affects rats' central nervous system histaminergic responses to dietary manipulation

The histaminergic system (histamine and its H1-receptor) of the central nervous system has been implicated in control of food intake. The reported studies were designed to examine the effects of food restriction and very low (1%) protein diets on central nervous system H1-receptors in male and female rats. In a series of experiments, groups of rats were freely fed a 25% protein diet, a 1% protein diet, or fed the 25% protein diet at 4 g/100 g body weight for 14-20 d. When freely fed 25% protein diets, females had higher whole-brain H1-receptor binding than males on d 1 (female 122.36 +/- 4.53 and male 65.78 +/- 3.82 pmol/g protein; P < 0.001). Changing diets affected central H1-receptor binding in both males and females (P < 0.003). When rats were fed both restricted levels of food and 1% protein diets, the receptor binding of males increased by d 5 whereas that of females decreased by d 5 (P < 0.001). When fed 1% protein diets, females had decreased H1-receptor binding (98.4 +/- 2.38 pmol/g protein) and that in males increased to 119.81 +/- 5.09 pmol/g protein. After 15 d, females had eaten significantly more food than males: females 166 +/- 4.9 g, males 124 +/- 1.9 g (P< 0.0007). Males had a significantly greater weight loss than females: males -28.8 +/- 2.6 g, females -17.08 +/- 0.97 g (P < 0.0007). When fed restricted diets, females had decreased H1-receptor binding (93.81 +/- 5.58 pmol/g) whereas binding in males increased to 111.27 +/- 8.55 pmol/g. Preliminary saturation binding studies indicated that restricted food intake lowered receptor density (females consuming 25% protein: 715 +/- 30 pmol/g protein; female restricted: 467 +/- 28 pmol/g protein, P < 0.05), while 1% protein increased receptor sensitivity, i.e., lowered KD (males consuming 25% protein: 15.3 +/- 1.8 nmol; males fed low protein: 2.8 +/- 0.27 nmol). This study suggests that dietary manipulation affects central H1-receptor binding in a gender-specific manner, thereby modulating central histaminergic activity during food or protein deficit.     

Effects of fish meal and sodium bentonite on daily gain, wool growth, carcass characteristics, and ruminal and blood characteristics of lambs fed concentrate diets

We evaluated the effects of replacing some soybean meal (SBM) protein with fish meal (FM) protein in diets adequate and slightly deficient in CP, with or without .75% sodium bentonite (NaB) on performance and ruminal and blood metabolites of individually fed Suffolk lambs. Diets were based on corn, SBM, and cottonseed hulls. In Exp. 1, five lambs were assigned to each of the three dietary treatments (11% CP with 3% FM, 13% CP with 0 or 3% FM). Lambs fed diets that contained 11% CP with 3% FM or 13% CP with 0% FM had similar DMI and ADG. Gain and feed efficiency were slightly improved (P = .18) by the 13% CP diet with 3% FM. In Exp. 2, 32 lambs were assigned to four dietary treatments (13.5% CP of DM) in a 2 x 2 factorial arrangement (0 or 3% FM, and 0 or .75% NaB on an as-fed basis). The DMI and ADG were increased (P < .05) by FM and NaB supplementation. Interactions (P < .05) revealed that NaB increased DMI, ADG, gain per feed (g/kg of DMI), and plasma urea N concentration in the absence of FM but not in the presence of FM in the diet. Neither FM nor NaB influenced (P = .25) wool growth. Total ruminal VFA were increased (P < .06) by FM and NaB. Differences in mineral content of phalanx bone, liver, and kidney were small and may be related to the mineral content of diets and the effect of NaB on mineral solubilities. Similar DMI and ADG of lambs fed FM and NaB separately and in combination suggest that their beneficial effect is not additive.     

Methionine requirement of channel catfish fed soybean meal-corn-based diets

A soybean meal-corn-based diet was used to determine dietary methionine (Met) required by 14-g channel catfish (Ictalurus punctatus) in a 42-d experiment at 25 degrees C. The basal diet with balanced limiting amino acids relative to the catfish whole-body amino acid profile contained 277 g of CP, 3.6 g of Met, 4.0 g of cystine (Cys), and 10 MJ of DE/kg of DM. DL-Methionine was added to the basal diet from 0 to 12.0 g/kg in 2-g intervals at the expense of L-glutamic acid to produce seven isonitrogenous and isocaloric diets. A reference diet contained 331 g of CP, 8 g of Met, 5 g of Cys, and 10 MJ of DE/kg of DM (included 8% fish meal). Seven graded Met levels resulted in quadratic responses (P < .01) of weight gain, specific growth rate, feed or GE intake, feed or energy efficiency, protein or energy retention, protein efficiency ratio, and apparent net protein or energy utilization. Channel catfish required 9.4 g of Met/kg of DM (34.1 g/kg of CP) with a total 11.3 g/kg of calculated digestible sulfur-containing amino acids based on multiple regression dose-response models or 270 mg of Met/kg of fish per day based on a broken-line response of protein gain to Met intake. At the adequate Met level, catfish with the lowest (P < .05) liver lipids showed feed intake and protein or energy utilization efficiency similar (P > .05) to that of catfish fed the reference diet. Catfish fed all-plant-protein diets require more dietary methionine than previously reported. Catfish fed corn-soybean meal diets fortified adequately with methionine result in performance that approaches that of fish fed a fish meal-based diet.     

Carry-over effects of dietary crude protein and triiodothyronine (T3) in broiler chickens

Indian River male broiler chickens growing from 7 to 30 d of age were fed on diets containing crude protein levels ranging from 120 to 300 g/kg plus 0 or 1 mg triiodothyronine (T3)/kg diet. The purpose of this study was to examine the effects of these treatments on lipogenesis after a common diet was fed (180 g crude protein/kg diet from 30 to 56 d of age). Dietary treatment groups were sampled at 30 and 56 d. In vitro lipogenesis was determined by incubating liver explants for 2 h at 37 degrees in Hanks' salts containing 25 mM-HEPES and 10 mM-[2-14C]acetate and then measuring acetate incorporation into total lipid. Growth and feed consumption from 7 to 30 d increased (P < 0.01) as dietary protein increased from 120 to 210 g/kg diet. Both measurements decreased as crude protein increased from 210 to 300 g/kg diet. T3 decreased (P < 0.01) growth and feed intake during this period. Low-protein (< 180 g/kg) diets increased (P < 0.05) and T3 decreased lipogenesis in 30-d-old chickens. Although birds given T3 from 7 to 30 d grew at the greatest rate from 30 to 56 d of age, the final body weight was still less than controls. In vitro lipogenesis at 56 d of age was not affected by either of the two dietary treatments. In contrast, the relative size of the abdominal fat pad (g/kg body weight) at 56 d was decreased by feeding T3 from 7 to 30 d. Any changes in metabolism elicited by either dietary protein levels or hormone treatments may be specific to the particular dosing interval and are not sustained when a common diet is fed during a repletion period.     

Alterations of pH in response to increased dietary protein in cattle are unique to the uterus

This study was undertaken with two objectives: 1) to determine whether the effect of excess dietary protein on intrauterine pH in cattle is specific to the uterus or manifested in other bodily fluids and 2) to determine whether the effect of excess ruminally degradable protein on uterine pH can be ameliorated by substitution with a less-degradable protein source. Thirty-six Holstein cows in early lactation were fed isoenergetic total mixed rations that either 1) met undegradable intake protein (UIP) and degradable intake protein (DIP) requirements (Balanced), 2) met DIP requirements and exceeded UIP requirements by 25% (High UIP), or 3) met UIP requirements and exceeded DIP requirements by 25% (High DIP). After diets had been fed > or = 2 wk, uterine, blood, salivary, and urinary pH and plasma urea nitrogen were determined at estrus (d 0) and d 7. Plasma urea nitrogen (mg/dL) was not different between estrus and d 7 but was significantly affected by diet (Balanced, 16.1 +/- 2.3; High UIP, 19.2 +/- 1.6; High DIP, 22.3 +/- 2.6; P < .05). There was no effect of treatment on the pH of any fluid measured at estrus: intrauterine, blood, salivary, and urinary pH averaged 6.84 +/- .05, 7.39 +/- .01, 8.30 +/- .05, and 8.15 +/- .05, respectively. In contrast, on d 7, uterine pH was significantly lower in both high-protein groups, regardless of protein degradability (Balanced, 7.13 +/- .05; UIP, 6.95 +/- .04; DIP, 6.85 +/- .05; P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

The professional identity of the nurse: concept analysis and development

Urea kinetics were measured in normal women after 5 d consuming a low protein diet [LP, 67 mg N/(kg.d), 0.42 g protein/(kg.d)]. To determine whether the availability of methionine limits the utilization of nonessential nitrogen from low protein diets, the study was repeated on four further occasions with the addition of dietary supplements of L-methionine, 9 mg N/(kg.d) (LP-M); urea, 52 mg N/(kg.d) (LP-U); urea and methionine (LP-UM); or urea, 26 mg N/(kg.d), and glycine, 26 mg N/(kg.d), (LP-UG). Urea kinetics were derived after prime and intermittent oral doses of [15N15N]urea from the measurements of enrichment by isotope ratio mass spectrometry in urea isolated from urine. Nitrogen balance was significantly improved when the women consumed LP-U and LP-UG, but not LP-M or LP-UM. The urinary excretion of 5-L-oxoproline was measured as a marker of glycine availability and was significantly lower when women consumed LP-U and LP-UG compared with either LP or LP-M and LP-UM. There was a significant correlation between urinary 5-L-oxoproline and urinary sulfate excretion (r = 0.68, P = 0.00003). The availability of methionine was not limiting for nitrogen metabolism when women consumed these diets, whereas the response to supplementation with urea alone or urea with glycine showed that the availability of nonessential nitrogen was limiting. Glycine is consumed in the detoxification of excess methionine, and supplementation with methionine appeared to place a competitive demand on the availability of glycine for other metabolic processes.