Use Of Low-protein Diets Research Articles

Myocardial effects of a low-protein diet in experimental kidney dysfunction

THE AIM: to evaluate the effect of low protein diet supplemented with ketosteril on morphological and epigenomic changes in the myocardium of Wistar rats with simulated kidney dysfunction . MATERIALS AND METHODS. The work was performed on male Wistar rats subjected to 5/6 nephrectomy (NE). The first group after NE received a standard diet (20.16% animal protein ), the second – low protein diet (LPD), including 10% ketosteril . Control rats received a standard diet . After 4 months , blood pressure (BP) and left ventricular mass index (LVMI) were assessed in rats , and a histological examination of the myocardium was performed . In the myocardium , the relative expression levels of NF- kB , miRNA-21, miRNA-133, and miRNA-203 were determined . RESULTS. After 4 months in rats with NE on a standard diet , an increase in blood pressure , an increase in the mass index of the LV myocardium was recorded . MBD with the inclusion of 10% Ketosteril slowed down the growth of systolic blood pressure and the development of LV myocardial hypertrophy in rats with kidney dysfunction . At the histological level , the use of LPD provided a decrease in the degree of hypertrophy of cardiomyocytes and degenerative changes in cardiomyocytes . Animals treated with LPD had less pronounced diffuse and perivascular fibrosis compared with animals fed normal food . The use of MBD slowed down the increase in the relative level of expression of the NFκB gene and miRNA-21 in the myocardium of rats with NE and promoted an increase in the expression level of miRNA-133 and miRNA-203 compared to the indices of animals with NE that received standard food . CONCLUSION: long-term use of LPD with the use of ketoanalogues of essential amino acids can have a potential cardioprotective effect in CKD, slowing down the growth of blood pressure , an increase in LV myocardial mass and the formation of structural changes in the myocardium . It is possible that a decrease in the expression of NF- kB and miRNA-21, as well as an increase in the expression of miRNA-203 and 133 in the myocardium , can play a significant role in this .

MO130: Effect of Long-Term Low Protein Diet Use at Myocardium Remodelling in Rats With Experimental Decrease of Working Nephrons Weight

Abstract BACKGROUND AND AIMS Cardiovascular disturbances are the most frequent cause of death in patients with chronic kidney disease (CKD). Various options of low protein diets (LPD) are widely used in CKD treatment. However, their role in cardioprotection at CKD is understudied. The aim was to study the features of myocardium remodelling in Wistar rats for a long period post-nephrectomy (NE), who received LPD that included 10% of the complex of indispensable amino acids and their keto analogues. METHOD The study was carried out on adult (2.5–3 months) Wistar male rats. The control group (C) consisted of 9 sham operated (SO) rats; the second group consisted of 8 animals, in whom the resection of 5/6 kidney tissue (NE) was performed with the purpose to create the renal dysfunction model. The rats from these two groups received the standard feed, containing 20.16% of animal protein. The rats from the third group (n = 12) received LPD that included 10% of the complex of indispensable amino acids and their keto analogues (Ketosteril, Fresenius Kabi, Germany) after 5/6 NE. Four months after NE, blood pressure (BP, mm Hg) was measured in the animals. The left ventricular muscle mass index (LVMMI) was calculated as a ratio of LV weight/body weight (mg/g). The morphological changes of the myocardium were evaluated by quantitative morphometry using VideoTest 5.2. Results are presented as mean ± SD. The Student's t-test and the Mann–Whitney test were used for statistical analysis. RESULTS In 4 months, the average BP level in the C group was 130 ± 5 mm Hg; in rats with NE on the standard diet, it was 158.7 ± 11.0 mm Hg, and in animals on LPD 130 ± 12.8 mm Hg (P < .001). In rats with NE on the standard diet, LVMMI (2.72 ± 0.11) was higher than in the C group (2.35 ± 0.09, P < .01). In rats with NE that received LPD, there was no significant change in this indicator versus the C group (P > .05). In rats with NE against LPD administration, the cardiocytes thickness (9.5 ± 1.9 µm) and the cardiocytes nuclei area (26.6 ± 4.7 µm2) decreased, the ratio of cardiocytes nuclei area and cardiocytes thickness (0.38 ± 0.14) versus animals at the standard diet (14.19 ± 0.08, µm; 34.1 ± 8.1 µm2; and 0.23 ± 0.03; P < .001 in all cases) increased. In the NE group on LPD, the number of polynuclear cardiocytes was less than (0.3%) versus the NE group on the standard diet (1%). The connective tissue area indicator was 2837.6 ± 1263.1 µm2 versus 4008.1 ± 2185.7 µm2 (P = .061) in rats that received common feed. The decrease in ratio of capillaries area (%)/cardiocytes area (%) in rats on LPD, more than two times versus the NE group on standard diet, was noted. This is mostly conditioned by decrease in area occupied by connective tissue to 12% (2837.60 ± 1263.19 µm2) and decrease in total capillaries cross section up to 5% (1061.1 ± 78.3 µm2) in rats with LPD. The decrease of perivascular fibrosis degree in animals on LPD was determined. However, the vessel wall thickness in the NE groups (NE + LPD and NE on standard diet 29.9 ± 7 µm and 26.4 ± 17.6 µm; р = 0.211, respectively) increases versus C group (17.6 ± 5.1; P = .03). CONCLUSION The use of LPD in rats with NE has a cardioprotective effect, inhibiting the BP increase and the LVMMI index growth. In terms of histology, this was expressed through the decrease of cardiocyte hypertrophy degree, decrease in nuclei area, decrease of nucleoplasmic ratio, diffuse and perivascular sclerosis area.

A low aromatic amino-acid diet improves renal function and prevent kidney fibrosis in mice with chronic kidney disease

Despite decades of use of low protein diets (LPD) in the management of chronic kidney disease (CKD), their mechanisms of action are unclear. A reduced production of uremic toxins could contribute to the benefits of LPDs. Aromatic amino-acids (AA) are precursors of major uremic toxins such as p-cresyl sulfate (PCS) and indoxyl sulfate (IS). We hypothesize that a low aromatic amino acid diet (LA-AAD, namely a low intake of tyrosine, tryptophan and phenylalanine) while being normoproteic, could be as effective as a LPD, through the decreased production of uremic toxins. Kidney failure was chemically induced in mice with a diet containing 0.25% (w/w) of adenine. Mice received three different diets for six weeks: normoproteic diet (NPD: 14.7% proteins, aromatic AAs 0.019%), LPD (5% proteins, aromatic AAs 0.007%) and LA-AAD (14% proteins, aromatic AAs 0.007%). Both LPD and LA-AAD significantly reduced proteinuria, kidney fibrosis and inflammation. While LPD only slightly decreased plasma free PCS and free IS compared to NPD; free fractions of both compounds were significantly decreased by LA-AAD. These results suggest that a LA-AAD confers similar benefits of a LPD in delaying the progression of CKD through a reduction in some key uremic toxins production (such as PCS and IS), with a lower risk of malnutrition.

Possible role of available phosphorus in potentiating the use of low-protein diets for broiler chicken production

A total of 945 male Ross 308 broiler chicks were used in a growth study to explore the interaction between dietary crude protein concentration and available phosphorus. Nine experimental treatments were constructed factorially by offering low, medium, or standard protein concentrations without or with low, standard, or high available phosphorus. Diets were based on corn, wheat, and soybean meal and all nutrients other than protein/amino acids and available phosphorus were maintained at or above breeder guidelines. Additional synthetic amino acids were used in the diets with low protein concentration in attempt to maintain digestible amino acid supply. Diets were offered to 7 replicate pens of 15 chicks per pen from day 8 to 35. Growth performance was measured during the grower (day 8–24) and finisher (day 25–35) periods. On day 35 carcass composition was determined, blood was drawn for various biochemical measurements and the tibia was excised for mechanical and compositional analyses. Birds that received the low-protein diet had lower terminal body weight and higher feed conversion ratio compared with those that received diets with adequate crude protein content. However, addition of available phosphorus to the low-protein diet resulted in significant reductions in weight-corrected feed conversion that were not evident in the diet with adequate protein content. Bone architecture was only moderately influenced by dietary treatment but birds that ingested the diets containing low and medium protein concentrations had relatively heavier abdominal fat pad weight. Blood biochemistry, especially ammonia, uric acid, and phosphorus, was influenced by both dietary protein and available phosphorus and trends suggested that both axes are involved in protein accretion and catabolism. It can be concluded that performance losses associated with feeding low protein diets to broiler chickens may be partially restored by additional available phosphorus. The implications for use of exogenous enzymes such as protease and phytase and protein nutrition per se warrants further examination.

Use of encapsulated L-lysine-HCl and DL-methionine improves postprandial amino acid balance in laying hens.

The supplementation of dietary limiting amino acids (AA) with crystalline AA makes the use of low-protein diets an option in poultry production. The differing absorption rates of crystalline and protein-bound AA may lead to temporally imbalanced AA in the postabsorptive period. In this study, two experiments were conducted to evaluate the effect of encapsulated L-lysine-HCl (L-Lys-HCl) and DL-methionine (DL-Met) on the laying performance of hens. In exp. 1, a total of 135 forty-seven-wk-old Hy-Line Brown hens were subjected to three dietary treatments for 8 wk: basal diet supplemented with 0.14% L-Lys-HCl and 0.17% DL-Met to satisfy the NRC (1994) total Lys and Met recommendation (control) and basal diet supplemented with encapsulated L-Lys-HCl and DL-Met at the levels of 60% (60CLM, 0.084% L-Lys-HCl and 0.102% DL-Met) or 80% of control (80CLM, 0.112% L-Lys-HCl and 0.136% DL-Met), respectively. In exp. 2, 24 fifty-five-wk-old Hy-Line Brown hens were individually reared in cages and subjected to the same treatments as in exp. 1. The plasma concentrations of free AA and nitrogen metabolites were measured 2, 4, and 6 h after fed. The results showed that dietary AA treatment had no significant influence on body weight (BW), feed intake, laying rate, egg weight, egg mass, or feed efficiency. The expression levels of AA transporters CAT-1, y+LAT1, b0,+AT, B0AT, rBAT, EAAT3, and PepT1 in the duodenum, jejunum, and ileum were not influenced (P > 0.05) by dietary treatment. There was an interaction of dietary AA treatment and time (P < 0.05) and the 80CLM hens exhibited higher concentrations of Lys (P < 0.05) than the controls at 2-h time point. In contrast, plasma Met concentration was not influenced (P > 0.05), while Cys was reduced in the 60CLM hens at every time point. The 80CLM hens had higher taurine concentrations than those receiving the control diet at every postprandial time point. In conclusion, these findings demonstrate that by using encapsulated form, the supplemental levels of synthetic L-Lys-HCl and DL-Met can be effectively reduced by approximately 20% with no negative effect on laying performance. The result suggests that encapsulated Lys and Met may ameliorate the postabsorptive AA balance and contribute to the reduced dietary AA supplemental levels.

P0922A LOW AROMATIC AMINO-ACID DIET IMPROVES RENAL FUNCTION AND PREVENTS KIDNEY FIBROSIS IN MICE WITH CHRONIC KIDNEY DISEASE

Abstract Background and Aims Despite decades of use of low protein diets (LPD) in the management of chronic kidney disease (CKD), the mechanisms through which it delays the progression to end-stage renal disease (ESRD) remain controversial. A reduced production of uremic toxins could contribute to the benefits of the LPD. Aromatic amino-acids are precursors of major uremic toxins such as p-cresyl sulfate (PCS), indoxyl sulfate (IS), indole-3-acetic acid or phenol. We investigated the hypothesis that a low aromatic amino acid diet (LAA, namely low intake of tyrosine, tryptophan and phenylalanine) while being normoproteic, could be as effective as a LPD, through the specific diminution of uremic toxins production. Method Renal failure was chemically induced in mice with a diet containing 0.25% (w/w) of adenine. Thereafter, they received 3 different diets for 6 weeks: normoproteic diet (NPD: 14.7% proteins, aromatics 0.019%), LPD (5% proteins, aromatics 0.007%) and LAA (14% proteins, aromatics 0.007%). Results LAA and LPD had no significant effect on body weight. Plasma creatinine was significantly lower in LPD and LAA groups compared to NPD group (72 ± 4 and 73 ± 4 µmol/L vs 127 ± 6 µmol/L, p&amp;lt;0.0001), as well as proteinuria (1.3 ± 0.3 and 1.2 ± 0.1 mg/24h vs 3.8 ± 0.9 mg/24h, p&amp;lt;0.05). Kidney fibrosis was more severe in NPD group vs LPD and LAA groups (17 ± 1% vs 10 ± 1 % and 13 ± 2 %, p&amp;lt;0.0001 and p=0.01). Kidney inflammation was also reduced with LPD and LAA. Free PCS and IS were lower in LPD and LAA groups compared to NPD group. Conclusion These results suggest that LAA confers similar benefits as compared with those of LPD to delay the progression of CKD through reduction of uremic toxins production, with lower risk of malnutrition. Renal function and urinary protein excretion in control and CKD mice Serum creatinine (A), blood urea nitrogen (B) and urinary proteins (C) in control and CKD mice fed with normoproteic diet (NPD), low protein diet (LPD) or low aromatic amino-acid diet (LAA). Data are expressed as mean ± SEM for n = 5-11 animals in each group. *p &amp;lt; 0.05, **p &amp;lt; 0.01, ***p &amp;lt; 0.001 vs CKD-NPD; (two-way ANOVA and Dunnett post hoc test).

Plant-based diets for prevention and management of chronic kidney disease.

Plant-based diets have been used with growing popularity for the treatment of a wide range of lifestyle-related diseases, including diabetes, hypertension, and obesity. With the reinvigoration of the dietary management of chronic kidney disease (CKD) and the use of low protein diets for secondary prevention of CKD to delay or prevent dialysis therapy, there is an increasing interest in the potential role of plant-based diets for these patients. Recently, a body of evidence related to the role of plant-based diets in preventing CKD has reemerged. Several observational studies have shown that red and processed meat have been associated with increased risk of CKD as well as faster progression in those with preexisting CKD. In several substitution analyses, replacement of one serving of red and/or processed meat has been linked with sizable reductions in CKD risk. Although limited, experimental trials for the treatment of metabolic acidosis in CKD with fruits and vegetables show outcomes comparable to oral bicarbonate. The use of plant-based diets in CKD may have other benefits in the areas of hypertension, weight, hyperphosphatemia, reductions in hyperfiltration, and, possibly, mortality. The risk of potassium overload from plant-based diets appears overstated, mostly opinion-based, and not supported by the evidence. Plant-based diets are generally well tolerated and provide adequate protein intake, including essential amino acids as long as the diet is correctly implemented. Plant-based diets should be recommended for both primary and secondary prevention of CKD. Concerns of hyperkalemia and protein inadequacy related to plant-based diets may be outdated and unsupported by the current body of literature. Healthcare providers in general medicine and nephrology can consider plant-based diets as an important tool for prevention and management of CKD.

Pathological changes of myocardium in the model of chronic renal insufficiency at application of low-protein diet

Myocardial damage in patients with chronic renal failure histologically manifests as hypertrophy of cardiomyocytes, intramyocardial artery walls, development of diffuse sclerosis and a change in the number of capillaries. One of the components in the complex treatment of this category of patients is a low-protein diet, however, to date there is no data on the effect of a low-protein diet on structural changes in the myocardium. The aim of the work was to assess the effect of low protein diet on myocardial structural changes in the experimental model of chronic renal failure. To reproduce the experiment of chronic renal failure, a standardized 5/6 nephrectomy model was used in wistar rats. To determine the effect of a low-protein diet on structural changes in the myocardium, two types of diet were used - a standard one and a low-protein diet (Ketosteril). The animals were sacrificed 4 months after nephrectomy. For a comparative assessment of the effect of low-protein diet on structural changes in the myocardium, histological methods of investigation and morphometry were used. The use of low-protein diet was accompanied by a less pronounced violation of biochemical blood parameters (creatinine, urea, calcium, phosphorus), as well as maintaining normal blood pressure, myocardial mass and left ventricular wall thickness. Histologically, this was manifested by a decrease in the severity of dystrophic changes in cardiomyocytes, the degree of their hypertrophy, a decrease in the area of nuclei, and a decrease in the nuclear-cytoplasmic ratio. Indices of perivascular and diffuse sclerosis were lower compared with the control group. Also, when using low-protein diet in animals with a chronic renal failure model, a decrease in the total cross-sectional area of capillaries was noted with an increase in their number in comparison with animals of the control group. Thus, the use of a low-protein diet in an experimental model of chronic renal failure has a cardioprotective effect by reducing the severity of uremia and stabilizing biochemical parameters.

047 Use of low protein diets for weanling pigs

047 Use of low protein diets for weanling pigs

Adherence to ketoacids/essential amino acids-supplemented low protein diets and new indications for patients with chronic kidney disease.

BackgroundLow protein diets (LPD) have long been prescribed to chronic kidney disease patients with the goals of improving metabolic abnormalities and postpone the start of maintenance dialysis.MethodsWe reviewed the recent literature addressing low protein diets supplemented with ketoacids/essential aminoacids prescribed during chronic kidney disease and their effects on metabolic, nutritional and renal parameters since 2013.ResultsWe show new information on how to improve adherence to these diets, on metabolic improvement and delay of the dialysis needs, and preliminary data in chronic kidney disease associated pregnancy. In addition, data on incremental dialysis have been reviewed, as well as potential strategies to reverse protein energy wasting in patients undergoing maintenance dialysis.ConclusionThese recent data help to better identify the use of low protein diets supplemented with ketoacids/essential aminoacids during chronic kidney disease.

Low-protein diets in CKD: how can we achieve them? A narrative, pragmatic review.

Low-protein diets (LPDs) have encountered various fortunes, and several questions remain open. No single study, including the famous Modification of Diet in Renal Disease, was conclusive and even if systematic reviews are in favour of protein restriction, at least in non-diabetic adults, implementation is lagging. LPDs are considered difficult, malnutrition is a threat and compliance is poor. LPDs have been reappraised in this era of reconsideration of dialysis indications and timing. The definition of a normal-adequate protein diet has shifted in the overall population from 1 to 1.2 to 0.8 g/kg/day. Vegan–vegetarian diets are increasingly widespread, thus setting the groundwork for easier integration of moderate protein restriction in Chronic Kidney Disease. There are four main moderately restricted LPDs (0.6 g/kg/day). Two of them require careful planning of quantity and quality of food: a ‘traditional’ one, with mixed proteins that works on the quantity and quality of food and a vegan one, which integrates grains and legumes. Two further options may be seen as a way to simplify LPDs while being on the safe side for malnutrition: adding supplements of essential amino and keto acids (various doses) allows an easier shift from omnivorous to vegan diets, while protein-free food intake allows for an increase in calories. Very-low-protein diets (vLPDs: 0.3 g/kg/day) combine both approaches and usually require higher doses of supplements. Moderately restricted LPDs may be adapted to virtually any cuisine and should be tailored to the patients' preferences, while vLPDs usually require trained, compliant patients; a broader offer of diet options may lead to more widespread use of LPDs, without competition among the various schemas.

Papel da dieta como fator de risco e progressão da nefropatia diabética

Diabetic nephropathy (DN) is the leading cause of kidney disease in patients starting renal replacement therapy, and affects up to 40% of type 1 and type 2 diabetic patients. Diet seems to play an important role in the development of the disease. There are evidences supporting the concept that not only the amount but also the origin of dietary protein are associated with DN. Few studies analyzed the role of dietary lipids. A low-protein diet slows down the decline of renal function and ameliorates the DN prognosis and death in patients with type 1 diabetes with micro- and macroalbuminuria. Studies in type 2 diabetic patients are scanty but short-term studies suggest that this approach decreases albuminuria. However, the use of low-protein diet for long periods is compromised by poor compliance and its long-term safety is not firmly established. Enthusiastic results come up when comparing the effect of different sources of animal protein on renal function and lipid profile in patients with DN, which may represent an alternative strategy for low-protein diet on medical nutritional therapy in patients with DN and in cardiovascular risk factors and endothelial function.

Growth and fur characteristics of blue foxes (Alopex lagopus) fed diets with different protein levels and with or without DL-methionine supplementation in the growing-furring period

A production trial was carried out on 125 growing-furring blue foxes (Alopex lagopus) to study the effects of low-protein diets, with or without DL-methionine supplementation, on growth performance and fur characteristics. The treatment codes were P30, P22.5, P22.5M, P15, and P15M. The protein contents [g kg-1 DM (dry matter)] of the diets were 300, 243, 243, 174, and 177, respectively. DL-methionine was added to P22.5M and P15M to yield a total dietary content of methionine (M) corresponding to that in P30. From August to mid-September, the weight gain of the blue foxes receiving the diet with the lowest protein level and the lowest methionine content (P15) was significantly lower than that of the blue foxes in treatments P22.5 and P30. In contrast, growth of the blue foxes in P15M did not differ from that of the blue foxes in P22.5 or P22.5M. From mid-September to pelting, weight gain did not differ significantly among treatments. Guard hair quality was significantly impaired in the low-protein diets without methionine supplementation, but not in those diets supplemented with methionine. Methionine appeared to be the first limiting amino acid for winter fur development. Addition of DL-methionine and use of low-protein diets for blue foxes would be beneficial in terms of reduced feed expenses and lower nitrogen emissions to the environment. Key words: DL-methionine, protein, amino acids, growth, fur skin quality, blue fox (Alopex lagopus)

The nutritional status of chronic renal failure patients following the initiation of hemodialysis treatment

The nutritional status of chronic renal failure patients following the initiation of hemodialysis treatment

The conservative management of chronic renal failure: Results of a recent survey

Opinions differ regarding the role of protein restriction in the progression of renal disease. Unfortunately the Modification of Diet in Renal Disease Study did not settle this controversy. To assess the use of low protein diets (LPDs) in the United Kingdom, renal dietitians were surveyed about the current dietetic practices and beliefs in their Renal Units. In the survey, 81% of questionnaires were returned (59 of 73), of these 35 Renal Units were using LPDs (<1 g/kg body weight). The majority (33) used LPDs for symptomatic relief and 20 for slowing progression. The use of LPDs in diabetic patients was similar to nondiabetic patients, but LPDs were started earlier by 12 Renal Units. Most (22) of the dietitians calculate LPDs on the basis of ideal body weight. Nutritional assessment was by weight (35), body mass index (26), serum albumin (31), and upper arm anthropometry (10). The lack of agreement, both within and outside of Renal Units will ensure that the debate regarding protein restriction continues.

Low Protein Diets for Channel Catfish Ictalurus punctatus Raised in Earthen Ponds at High Density1

AbstractThis study was conducted to evaluate the use of low protein diets for channel catfish Ictalurus punctatus raised in earthen ponds at high density. Fingerling channel catfish were stocked into 0.04‐ha earthen ponds at a rate 24,700 fish/ha and fed experimental diets daily to satiation from April to October 1995. The five diets contained either 32, 28, 24, 20, or 16% crude protein with digestible energy to protein (DE:P) ratios ranging from 8.9 to 16.2 kcal/ g protein. Weight gain was not different among channel catfish fed diets containing 32, 28, or 24% crude protein. Fish fed diets containing 20% or 16% crude protein gained less weight than fish fed the diets containing 28% or 24% crude protein, but not statistically less than the fish fed the 32% crude protein diet. Feed consumption data followed similar trends as weight gain data. Feed conversion ratio increased linearly as dietary protein decreased, but was not significantly different (multiple range test) for fish fed diets containing either 32% or 28% crude protein. There were no differences in survival and hematocrit of fish fed the different diets. No differences (multiple range test) were observed in dressout percentages for fish fed the various diets, but dressout percentage tended to decrease linearly as dietary protein decreased. Visceral fat and fillet fat increased and fillet protein and moisture decreased linearly as dietary protein decreased. Results from this study indicated that dietary protein concentrations as low as 24% are adequate for maximum weight gain of pond‐raised channel catfish fed daily to satiation. Fish fed dietary protein levels below 24% grew relatively well, particularly considering that dietary protein was reduced 40–50% below that typically used in commercial channel catfish feeds. However, dietary protein levels below 24% may increase fattiness to an unacceptable level presumably because of the high digestible energy to protein ratio.

Role of nutrition in prevention of the progression of renal disease.

In rats with renal disease, low-protein diets slow the decline in renal function, histologic damage, and mortality. Low-protein (and phosphorus) diets can also ameliorate uremic symptoms, secondary hyperparathyroidism, and metabolic acidosis in patients with chronic renal failure. Albeit controversial, evidence also suggests that dietary protein restriction can slow the rate of progression of renal failure and the time until end-stage renal failure. These dietary regimens appear to be safe and patients with chronic renal failure are able to activate normal compensatory mechanisms designed to conserve lean body mass when dietary protein intake is restricted. When low-protein diets are prescribed, patients should be closely monitored to assess dietary compliance and to ensure nutritional adequacy. Evidence that the spontaneous intake of dietary protein decreases in patients with progressive chronic renal failure who consume unrestricted diets should not be construed as an argument against the use of low-protein diets. Rather, it is a persuasive argument to restrict dietary protein intake in order to minimize complications of renal failure while preserving nutritional status.

Hypothesis: Insulin is responsible for the vascular complications of diabetes

It is proposed that the systemic hyperinsulinemia and hepatic portal hypoinsulinemia that occurs with conventional injectable preparations of insulin currently used in the treatment of patients with diabetes mellitus is largely responsible for the morbidity associated with this disease. Epidemiological evidence and animal experimentation strongly support systemic hyperinsulinemia as a major factor in genesis of atherosclerosis in diabetic patients. In addition, in vitro studies demonstrate a direct effect of insulin on endothelial cell and arterial smooth muscle proliferation. On the other hand, inadequate hepatic delivery of insulin is associated with overproduction of renal vasoregulatory factors leading to glomerular hyperfiltration and ultimately to glomerulosclerosis and its clinical endpoint — end-stage renal disease. In the absence of widespread success of pancreatic and islet-cell transplantation as a means to deliver insulin physiologically into the hepatic portal circulation, methods must be devised and perfected to accomplish such delivery using approaches such as orally administering insulin in intestinal-enzyme protected capsules. Until such methods of delivery are available for safe and widespread use, one should abandon the illusory goal of rigid glucose control in favor of methods that reduce insulin requirement. Along these lines, dietary restriction and aerobic exercise should be the major life style changes advised for diabetic patients. Reduction of glomerular hyperfiltration in diabetic patients can be promoted with the use of low protein diets and/or angiotensin converting enzyme inhibitors.

Influence of Nutrient Density on Growth and Carcass Composition of Weight-Segregated Leghorn Pullets

Leghorn pullets were weight-segregated at either 8, 12, or 16 weeks of age and classified as either light, medium, or heavy weight. Six replicate cages each containing 10 birds of each of the three weight groups received a control diet ad libitum that contained 15% CP and provided 2800 kcal ME/kg. The same replicate number of light-weight pullets were also offered either high protein (18% CP, 2800 kcal ME/kg) or low energy (15% CP, 2400 kcal ME/kg) diets. Groups of heavy pullets received either low protein (12% CP, 2810 kcal/kg) or high energy (15% CP, 3200 kcal/kg) diets. Feed intake and body weight were recorded at 12, 16, and 19 weeks of age. At 19 weeks of age, 12 birds per treatment were sacrificed for carcass analysis.Diet modification had no beneficial effect on stimulating the growth rate of light pullets regardless of age. High protein diets increased protein intake of the light pullets (P<.05), although this was not related to growth or carcass composition. Feeding light pullets a low energy diet resulted in reduced energy intake (P<.05), contrary to the situation previously reported with unsegregated pullets. Feeding a high energy diet to the heavy pullets resulted in increased energy intake (P<.05) with no moderating effect on growth rate. Growth rate of the heavy pullets was tempered through use of low protein diets introduced at 8 or 16 weeks of age. Feeding the high energy diet to heavy pullets resulted in a consistent trend for increased carcass fat content. A possible explanation for these results is that genotype is largely responsible for early differences in body weight.

Total parenteral nutrition in experimental uremia: studies of acute and chronic renal failure in the growing rat.

The effects of total parenteral nutrition (TPN) on experimental acute and chronic renal failure were studied with special reference to age in the rat. TPN prolonged survival in acute renal failure. The young experimental animals benefitted more than the TPN. The accumulation of urea in the body was inhibited during TPN. In chronic renal failure, the low nitrogen TPN with essential amino acids as the source of nitrogen had no advantages over a regular diet fed ad libitum. Instead the TPN-rats had a markedly less positive nitrogen balance than the uremic and healthy controls. This difference was accentuated in the rapidly growing young animals. The results of this study suggest that TPN has a crucial role in the treatment of acute renal failure at an early age and are against the use of low protein diets in chronic renal failure if rapid growth is expected.