Low-protein diet supplemented with 1% L-glutamine improves growth performance,serum biochemistry,redox status,plasma amino acids,and alters fecal microbiota in weaned piglets

Glutamine,one of the most abundant amino acids in the body,has been shown to exert various beneficial effects in pigs.However,knowledge regarding the role of dietary glutamine in low-protein diet-fed piglets remains scarce.The present study aimed to investigate the effects of different levels of L-gluta-mine on growth performance,serum biochemistry parameters,redox status,amino acids,and fecal microbiota in low-protein diet-fed piglets.A total of 128 healthy crossbred piglets(Landrace x Yorkshire)were randomly allocated into 4 groups of 4 replicate pens,with 8 piglets per pen.Piglets in the 4 groups were fed with corn and soybean meal-based low-protein diets(crude protein level,17%)that contained 0%,1%,2%,and 3%L-glutamine,respectively,for 28 d.Pigs administered 1%L-glutamine had greater body weight on d 28 and average daily gain(ADG,P<0.01),whereas a lower feed to gain ratio(F:G)from d 1 to 28(P<0.01),compared to the other three groups.Besides,lower body weight on d 14 and 28,ADG,average daily feed intake,and higher F:G from d 15 to 28 and d 1 to 28 were observed in response to 2%and 3%L-glutamine treatments than 0%and 1%L-glutamine treatments(P<0.01).Moreover,1%L-glutamine reduced serum glucose,malondialdehyde,hydrogen peroxide concentrations and inhibited aspartate aminotransferase,alanine aminotransferase,myeloperoxidase activities in low-protein diet-fed piglets on d 14,with concomitantly upregulated catalase,total superoxide dismutase activities and glutathione level(P<0.05).However,dietary 3%L-glutamine enhanced blood urea nitrogen content in pigs on d 14(P<0.05).Further investigation revealed that 1%L-glutamine upregulated the serum glutamine,lysine,methionine,tyrosine,and reduced plasma valine content(P<0.05).Additionally,1%L-glutamine upregulated the abundance of p_75_a5,Clostridium,Lactobacillus,Prevotellaceae_Prevotella,and Gemmiger in the stool of piglets on d 14,with the Streptococcus level being concomitantly reduced(P<0.05).Collectively,dietary 1%L-glutamine enhances the growth performance and improves serum physiochemical parameters and antioxidative capacity in low-protein diet-fed piglets at an early age,which are associated with an increased synthesis of glutathione by modulating amino acid levels,and the optimization of gut microbiota.

Studies on Reducing Nitrogen Excretion: Ⅰ. Net Energy Requirement of Finishing Pigs Maximizing Performance and Carcass Quality Fed Low Crude Protein Diets Supplemented with Crystalline Amino Acids

Two experiments were conducted to in- vestigate the effects of net energy （NE） level on the performance and carcass traits of finishing pigs fed low crude protein （CP） diets supplemented with crystalline amino acids （CAA）. A total of 216 （Exp. 1） and 360 （Exp. 2 ） barrows （ Yorkshire × Landrace× Duroc ） were allotted to one of six treatments （n =6）. The experimental diets were based on corn and soybean meal, and consisted of a high-CP diet that contained approximately 16% CP and 2.50 Mcal/kg of NE as well as five low-CP diets in which the CP level of the diet was reduced by approximately four percentage units but was supplemented with crystalline lysine, methionine, threonine, and tryptophan. The low CP diets provided 2.64, 2.58, 2.50, 2.42, or 2.36 Mcal/kg in Exp. 1 as well as 2.45, 2.40, 2.35, 2.30, or 2.25 Mcai/kg in Exp.2. In Exp. 1, a linear （P=0.03） increase in weight gain was observed with decreasing NE level while the ratio of gain to feed was unaffect- ed （P 〉 0.05） by NE level. There was a linear in-crease （P = 0.01 ） in the percentage of fat-free lean and a linear decrease （ P = 0.03 ） in the percentage of total fat with decreasing NE levels. In Exp. 2, a sig- nificant quadratic （ P = 0.03 ） effect of NE level was observed for weight gain. The ratio of gain to feed demonstrated a significant （P 〈0.01 ） quadratic effect with pigs fed 2.35 and 2.40 Mcal/kg of NE, Pigs fed the diet containing 2.40 Mcal/kg of NE had the lowest percentage of total fat （36. 95% ） and the highest percentage of fat-free lean （49.36%）. The overall results of these experiments indicate that feed- ing either a surplus or a deficiency of NE is detrimen- tal to both pig performance and carcass composition when low CP diets supplemented with CAA are fed. Our results indicate that when the CP content of the diet is reduced by four percentage units and the diet is properly supplemented with CAA, maximum per- formance and carcass quality will be obtained if the diet provides approximately 2.42 Mcal/kg of NE.

Effect of xanthan gum on the quality of low sodium salted beef and property of myofibril proteins

The effects of xanthan gum (0 % and 0.3 %) on the quality of low sodium (2.0 %, 2.4 %, 2.8 %, 3.2 %, 3.6 % and 4.0 %) salted beef and property of myofibril proteins (MP) extracted from salted beef were researched. Changes in the salting absorptivity, cooking loss, shear force, color and sensory analysis showed that xanthan gum had a positive effect on the quality of salted beef with low salinity (2.0 %, 2.4 % and 2.8 %). MP of salted beef treated with xanthan gum had higher solubility, lower hydrogen bond than that without it (P < 0.05). The decrease of surface hydrophobicity and intrinsic fluorescence intensity indicated that the chromophore of protein was brought into a hydrophobic environment in the presence of xanthan gum. The electrophoresis showed that xanthan gum could improve the concentration of myosin heavy chain, paramyosin and actin after tumble-salting. The data suggested that salted beef and its MP treated with xanthan gum and 2.8 % salt (XS3) had the best properties. Together, xanthan gum could be considered as a sodium salt substitute for the development of low sodium meat products.

The optimal dietary arginine level of laying hens fed with low-protein diets

Background:Arginine(Arg)is an essential amino acid(EAA)in poultry,an important substrate for protein synthesis and a precursor of several molecules.Supplementation of EAAs with low protein(LP)diet increases the utilization efficiency of dietary crude protein(CP).However,if the EAA requirement is changed in hens fed a LP diet remains to be elucidated.The aim of the present study was to evaluate the optimal level of dietary Arg in the LP diet of hens.A total of 1350 Hy-Line Brown laying hens were randomly allocated to six dietary treatments:a basal diet(16%CP,positive control),or an isoenergetic LP diet(14%CP,0.80%Arg)supplemented 0,0.05%,0.10%,0.15%,and 0.20%L-Arg,corresponding to 0.80%,0.85%,0.90%,0.95%and 1.00%dietary Arg,respectively.Results:The feed efficiency was decreased(P<0.05)by 0.80%and 1.00%Arg-LP diets,compared to control.Within LP diets,dietary Arg level had significant quadratic effects(P<0.05)on laying rate,egg mass,and feed efficiency.Compared to control,the plasma CAT activity or T-AOC content were decreased by 0.80%(P<0.001).However,the hens offered 0.85%and 0.90%Arg-LP diets had higher CAT activity(P<0.001)than 0.80%Arg-LP diet.In contrast,1.00%Arg-LP group had the highest MDA and the lowest T-AOC content in plasma,liver,duodenal and jejunal mucosa(P<0.05).Compared to control,the villus height was decreased by 0.80%,0.95%and 1.00%Arg-LP diets,while the villus height to crypt depth(V/C)ratio was reduced by 0.95%and 1.00%Arg-LP diets in duodenum.Conclusion:The result demonstrates that LP diet(14%CP)deficient in Arg(0.80%Arg)result in augmented oxidative damage and impaired development of intestinal mucosa.According to the quadratic broken-line regression model,the optimal dietary arginine levels for Hy-Line Brown laying hens fed with low protein diet(14%CP)aged 33 to 40 weeks are 0.85%,0.86%,and 0.86%to obtained the maximum laying rate,egg mass,and feed efficiency,respectively.

Effects of Low Protein Diets Supplemented with Ami-no Acids on Production Performance,Carcass Qual-ity and Input-output Ratio of Pigs

[ Objectives ] To study the effects of low-protein diets supplemented with amino acids on the production performance, carcass quality and input-output ratio of fattening pigs and growing-finishing pigs. [ Methods] Two studies were conducted on fattening pigs and growing pigs respectively. Pigs in two experimental groupswere fed with low-protein diets supplemented with amino acids and normal diets respectively, and the initial weight, final weight, feed consumption and car- cass index of the tested pigs were measured. [ Results] The average final weight of fattening pigs in test group was 2.4 kg lower than that in control group, while the difference was not significant （P 〉 0.05 ）. The average daily gain of fattening pigs in test group was 60 g lower than that in control group, indicating that low protein diets had a tendency to decrease the growth rate （P 〉 0.05 ）, and reduction of daily weight gain in low protein diet pigs reached 7.6%. The development of pigs in low protein diet group was poor, however, the difference was not significant. Carcass backfat thickness in low-protein diet group was slightly higher than that in control group, the difference was significant （ P 〈 0.05 ）. There was no significant difference in input-output ratio between low-protein diet group and control group. Finalweight of growing-finishing pigs in low-protein diet group was 3.22 % lower than that in control group, the average daily weight gainwas 6.91% lower than that in control group, feed intake in test group was 5.48% lower than that in control group, and difference between the two treatments was significant （P 〈 0.05 ）. Feed meat ratio in low-protein diet group improved, however, the difference was not significant（P 〉0.05）. [ Conclusions] Production performance of the pigs would be decreasedand the input-output ratio could not be improvedwhen the adding contents of crude protein in diets was reduced 3% -4%. Therefore, it is recommended that the crude protein level should be enough when pigs were fed with low-protein diets.

Low-protein diets supplemented with casein hydrolysate favor the microbiota and enhance the mucosal humoral immunity in the colon of pigs

Background:High-protein diets can increase the colonic health risks.A moderate reduction of dietary crude-protein(CP)level can improve the colonic bacterial community and mucosal immunity of pigs.However,greatly reducing the dietary CP level,even supplemented with all amino acids(AAs),detrimentally affects the colonic health,which may be due to the lack of protein-derived peptides.Therefore,this study evaluated the effects of supplementation of casein hydrolysate(peptide source)in low-protein(LP)diets,in comparison with AAs supplementation,on the colonic microbiota,microbial metabolites and mucosal immunity in pigs,aiming to determine whether a supplementation of casein hydrolysate can improve colonic health under very LP level.Twenty-one pigs(initial BW 19.90±1.00 kg,63±1 days of age)were assigned to three groups and fed with control diet(16%CP),LP diets(13%CP)supplemented with free AAs(LPA)or casein hydrolysate(LPC)for 4 weeks.Results:Compared with control diet,LPA and LPC diet decreased the relative abundance of Streptococcus and Escherichia coli,and LPC diet further decreased the relative abundance of Proteobacteria.LPC diet also increased the relative abundance of Lactobacillus reuteri.Both LP diets decreased concentrations of ammonia and cadaverine,and LPC diet also reduced concentrations of putrescine,phenol and indole.Moreover,LPC diet increased total short-chain fatty acid concentration.In comparison with control diet,both LP diets decreased protein expressions of Toll-like receptor-4,nuclear factor-κB,interleukin-1βand tumor necrosis factor-α,and LPC diet further decreased protein expressions of nucleotide-binding oligomerization domain protein-1 and interferon-γ.LPC diet also increased protein expressions of G-protein coupled receptor-43,interleukin-4,transforming growth factor-β,immunoglobulin A and mucin-4,which are indicators for mucosal defense activity.Conclusions:The results showed that supplementing casein hydrolysate showed beneficial effects on the colonic microbiota and mucosal immunity and barrier function in comparison with supplementing free AAs in LP diets.These findings may provide new framework for future nutritional interventions for colon health in pigs.

Effect of low-protein diet with supplementing different levels of DL-methionine on production performance of minks in growing-furring period

A study was conducted to evaluate production performance of minks in growing-furring period with supplementing DL-Methinnine （Met） in low protein diet. Seventy healthy male minks were randomly divided into five groups of 14 minks each. The minks were fed in five kinds of experiment diets （HP, LP, LP＋M1, LP＋M2 and LP＋M3）. The dietary protein levels, expressed as percentage of dry matter （DM）, were 32% （high protein, HP） and 24% （low protein, LP）. LP was supple- mented with Met 0.4% （M1）, 0.8% （M2） and 1.2% （M3） DM. From mid of September to December 10, apparent digestibility of CP （crude pro- tein）, N intake and urinary N excretion were decreased with declining dietary protein levels （p 〈 0.05） and N retained was the highest in treat- ment LP＋M2. No significant difference was found in total serum protein （TP） and serum urea nitrogen （SUN） among all treatment groups （p 〉 0.05）. Skin length of treatment HP and LP^M2 was higher than that of other groups （p 〈 0.05）. Body length, skin weight, length of guard hair and under hair were not affected by different dietary protein levels （p〉0.05）. The best performance could be observed in treatment LP＋M2. In diet, 24% （DM） protein level with 1.54% Met supplementing was enough for minks during growing-farring period. Dietary protein lowered from 32% to 24% with supplementing Met in diets would result in a37.9% decrease in urinary N excretion. Furthermore, addition of Met in diets for minks would be beneficial in terms of reducing feed expenses and lessening nitrogen emissions to the environment.

Apoptosis induced by a low-carbohydrate and high-protein diet in rat livers

AIM: To determine whether high-protein, high-fat, and low-carbohydrate diets can cause lesions in rat livers.METHODS: We randomly divided 20 female Wistar rats into a control diet group and an experimental diet group. Animals in the control group received an AIN-93 M diet, and animals in the experimental group received an Atkins-based diet(59.46% protein, 31.77% fat, and 8.77% carbohydrate). After 8 wk, the rats were anesthetized and exsanguinated for transaminases analysis, and their livers were removed for flow cytometry, immunohistochemistry, and light microscopy studies. We expressed the data as mean ± standard deviation(sd) assuming unpaired and parametric data; we analyzed differences using the student's t-test. statistical significance was set at P < 0.05.RESULTS: We found that plasma alanine aminotransferase and aspartate aminotransferase levels were significantly higher in the experimental group than in the control group. According to flow cytometry, the percentages of nonviable cells were 11.67% ± 1.12% for early apoptosis, 12.07% ± 1.11% for late apoptosis, and 7.11% ± 0.44% for non-apoptotic death in the experimental diet group and 3.73% ± 0.50% for early apoptosis, 5.67% ± 0.72% for late apoptosis, and 3.82% ± 0.28% for non-apoptotic death in the control diet group. The mean percentage of early apoptosis was higher in the experimental diet group than in the control diet group. Immunohistochemistry for autophagy was negative in both groups. sinusoidal dilation around the central vein and small hepatocytes was only observed in the experimental diet group, and fibrosis was not identified by hematoxylin-eosin or Trichrome Masson staining in either group.CONCLUSION: Eight weeks of an experimental diet resulted in cellular and histopathological lesions in rat livers. Apoptosis was our principal finding; elevated plasma transaminases demonstrate hepatic lesions.

Low saturated fat diet is effective in trigeminal neuralgia

Objective: To determine the effectiveness of low saturated fat diet (LSFD) in patients with trigeminal neuralgia (TN). Design: 1) Internet forum where patients could request a 10 page LSFD plan, and 2) Follow-up assessment done by a retrospective 20-item questionnaire. Duration of treatment—2 months to 13 years. Pain rated on a Visual Analogue Scale and reported as typical, atypical, or both, defining typical TN as intermittent quick jolts/stabbing pain and atypical TN as continuous never ending discomfort. Setting: General community. Patients: 55 unselected patients, most with unilateral, severe and daily symptoms in V2 and V3 distribution for a mean duration of 8 years and on medications. 84% had pain level 9-10 before treatment, 89% had daily attacks and 31% had undergone surgical procedures. Intervention: LSFD for 2 months-13 years (mean 20 months). Main outcome measure: VAS score and medication use before and after LSFD treatment. Results: Reported SF content was 3-25 gm. With treatment 96% typical TN (p Conclusions: LSFD is effective in TN with high compliance, few adverse effects and may result in reduction/ elimination of medications even in most severe cases.

Effects of Low Protein Diets on Nutrient Digestibility and Excretion in Finishing Pigs

The experiment was conducted to study the effects of low protein diets on nutrient digestibility and excretion of finishing pigs. For the 30-d trial,fortytwo duroc × landrace × yorkshire( DLY) finishing pigs with the initial weight of( 91. 13 ± 1. 64) kg were randomly divided into two groups,with three replicates in each group. The pigs in the two groups were fed with different crude protein( CP) levels( control groups: 15. 49% and low protein groups: 12. 59%). The results showed that:( 1) The digestibility of dry matter and crude fat( CF) in low protein groups were increased significantly( P < 0. 01),but there were no significant differences in digestibility among CP,calcium( Ca) and phosphorus( P);( 2) The digestibility of arginine( Arg) in low protein groups were 2. 02%( P <0. 05) lower than that in control groups. However,the digestibility of other amino acid were no difference between two groups;( 3) The nitrogen( N) excretion in low protein groups was 23. 96%( P < 0. 05) lower than that in control groups,but there were no significant differences in excretion among organic matter,P and Ca( P > 0. 05). The results showed that 2. 9% reduction of the CP in diets could improve nutrient digestibility and reduce the excretion of N,but reduced the digestibility of Arg.

Idiopathic Reactive Hypoglycemia: Mechanisms of Onset and Remission with High Protein Low Carbohydrate Diet

Objective: Idiopathic reactive hypoglycemia is defined as early postprandial hypoglycemia occurring on ingestion of high carbohydrate containing meal. Remission ensues with high protein low carbohydrate diet. This study assessed roles of insulin and glucagon in its onset and remission. Methods: Plasma glucose, insulin and glucagon were determined after an overnight fast and repeatedly until 180 minutes on ingestion of 3 meals;100 g glucose;100 g pure protein liquid and mixture of 50 g each at 14 days’ interval. Five adults with IRH and 6 age matched healthy volunteers participated. Results: In IRH, glucose ingestion induced prompt rise in glucose (5.1 ± 0.8 to10.5 ± 1.2 mM/L) followed later by hypoglycemia (2.6 ± 0.4 mM/L). Insulin rose from 7 ± 2 to 90 ± 18 mU/L. Glucagon rose initially (10% ± 2%) from elevated basal concentration (373 ± 57 mU/L) followed by later decline (-43% ± 12%). On protein ingestion, glucose declined followed by a restoration to basal level while both insulin and glucagon rose (28 ± 6 mU/L;148% ± 38%, p < 0.01). However, insulin response was lower and glucagon rise was greater when compared to responses on glucose ingestion (p < 0.01). With mixed meal, glucose (8.2 ± 0.6 mM/L), insulin (65 ± 12 mU/L) and glucagon (48% ± 7%) responses were lesser than rises following glucose ingestion (p < 0.05) and hypoglycemia did not occur. Conclusion: In IRH, initial hyperglycemia on glucose ingestion may be exacerbated by paradoxical glucagon rise and hypoglycemia may be induced by increased insulin and declining glucagon responses. Resolution of hypoglycemia with high protein low carbohydrate diet may be attributed to blunting of insulin response and concurrent glucagon rise.

Maternal low protein diet and fetal programming of lean type 2 diabetes

Maternal nutrition is found to be the key factor that determines fetal health in utero and metabolic health during adulthood.Metabolic diseases have been primarily attributed to impaired maternal nutrition during pregnancy,and impaired nutrition has been an immense issue across the globe.In recent years,type 2 diabetes(T2D)has reached epidemic proportion and is a severe public health problem in many countries.Although plenty of research has already been conducted to tackle T2D which is associated with obesity,little is known regarding the etiology and pathophysiology of lean T2D,a variant of T2D.Recent studies have focused on the effects of epigenetic variation on the contribution of in utero origins of lean T2D,although other mechanisms might also contribute to the pathology.Observational studies in humans and experiments in animals strongly suggest an association between maternal low protein diet and lean T2D phenotype.In addition,clear sex-specific disease prevalence was observed in different studies.Consequently,more research is essential for the understanding of the etiology and pathophysiology of lean T2D,which might help to develop better disease prevention and treatment strategies.This review examines the role of protein insufficiency in the maternal diet as the central driver of the developmental programming of lean T2D.

Analysis of Overall Popularization of Low-Protein Diet

The shortage of protein feed resources and environmental pollution restrict the healthy and sustainable development of breeding industry,so it is imperative to promote low protein diet. Based on the current industry trends and national policies, this paper analyzes the background con-ditions, significance and specific measures of popularizing low-protein diets, in order to provide policy, theoretical and technical support for the im-plementation of low-protein diets throughout the year.

Effect of low protein diet combined with drug therapy on renal function and oxidation - anti-oxidation balance in patients with diabetic nephropathy

Objective:To study the effect of low protein diet combined with drug therapy on renal function and oxidation - anti-oxidation balance in patients with diabetic nephropathy.Methods: Patients with diabetic nephropathy who were treated in the Second People's Hospital of Deyang City between July 2014 and March 2017 were collected, retrospectively analyzed and then divided into two groups according to the application of low protein diet intervention or not, observation group received low protein diet combined with drug therapy, and control group accepted routine drug therapy. The contents of renal function indexes, oxidative products and antioxidant indexes in serum as well as the expression of podocyte injury markers in urine were measured before treatment and 3 months after treatment.Results: 3 months after treatment, BUN, Scr, CysC, Hcy, MDA and AOPP contents in serum as well asα-actinin-4, ZO-1, nephrin and podocinde mRNA expression in urine of both groups were lower than those before treatment whereas CAT, SOD and T-AOC contents in serum were higher than those before treatment, and BUN, Scr, CysC, Hcy, MDA and AOPP contents in serum as well asα-actinin-4, ZO-1, nephrin and podocinde mRNA expression in urine of observation group were lower than those of control group whereas CAT, SOD and T-AOC contents in serum were higher than those of control group.Conclusion:Low protein diet combined with drug therapy can improve the renal function and the oxidation - anti-oxidation balance in patients with diabetic nephropathy.

Effect of different dietary protein levels and amino acids supplementation patterns on growth performance, carcass characteristics and nitrogen excretion in growing-finishing pigs

Background:This study was conducted to determine the effects of different dietary protein levels and amino acids supplementation patterns in low protein diets on the growth performance,carcass characteristics and nitrogen excretion in growing-finishing pigs.Forty-two barrows(25.00±0.39 kg)were randomly assigned to 7 diets.Diet 1:the high crude protein diet with balanced for 10 essential amino acids(EAAs).Diet 2:the medium crude protein diet with 2%(approx)decreased protein level of Diet 1 and balanced 10 EAAs.Diet 3:the low crude protein diet with 4%decreased protein level of Diet 1 and balanced 10 EAAs.The protein levels of Diet 4,5,6 and 7 were the same as that of Diet 3.Diet 4 was only balanced for lysine(Lys),methionine(Met),threonine(Thr)and tryptophan(Trp);Diet 5 and 6 were further supplemented with extra isoleucine(Ile)or valine(Val),respectively;Diet 7 was further supplemented with extra Ile+Val.Results:Over the 112 days trial,the reduction of dietary protein by 2%or 4%with balanced10 EAAs significantly decreased nitrogen excretion(P<0.05),but had no effects on growth performance and carcass characteristics(P>0.05).In low protein diet,Val supplementation significantly increased body weight gain at 25–50 kg phase(P<0.05),while Ile supplementation at 75–100 kg phase and 100–125 kg phase significantly reduced the ratio of feed to gain(P<0.05).No effect of different dietary protein levels and amino acids supplementation patterns in low protein diets on carcass characteristics was observed(P>0.05).The total N excretion of pigs supplemented with only Lys,Met,Thr and Trp was numerically higher than that of pigs fed with extra Ile,or Val,or Ile+Val diets.Conclusion:In low protein diet,Val is more required than Ile in the early growing phage(25–50 kg),while Ile becomes more required in the late growing and finishing phage(75–125 kg).

Long-term effects of early antibiotic intervention on blood parameters,apparent nutrient digestibility, and fecal microbial fermentation profile in pigs with different dietary protein levels

Backgroud： This study aimed to determine the effects of early antibiotic intervention（EAI） on subsequent blood parameters, apparent nutrient digestibility, and fecal fermentation profile in pigs with different dietary crude protein（CP） levels. Eighteen litters of piglets（total 212） were randomly allocated to 2 groups and were fed a creep feed diet with or without in-feed antibiotics（olaquindox, oxytetracycline calcium and kitasamycin） from postnatal d 7 to d 42. On d 42, the piglets within the control or antibiotic group were mixed, respectively, and then further randomly assigned to a normal-（20%, 18%, and 14% CP from d 42 to d 77, d 77 to d 120, and d 120 to d 185,respectively） or a low-CP diet（16%, 14%, and 10% CP from d 42 to d 77, d 77 to d 120, and d 120 to d 185,respectively）, generating 4 groups. On d 77（short-term） and d 185（long-term）, serum and fecal samples were obtained for blood parameters, microbial composition and microbial metabolism analysis.Results： EAI increased（P 〈 0.05） albumin and glucose concentrations in low-CP diet on d 77, and increased（P 〈 0.05） urea concentration in normal-CP diet. On d 185, EAI increased（P 〈 0.05） globulin concentration in normal-CP diets, but decreased glucose concentration. For nutrient digestibility, EAI increased（P 〈 0.05）digestibility of CP on d 77. For fecal microbiota, the EAI as well as low-CP diet decreased（P 〈 0.05） E. coli count on d 77. For fecal metabolites, on d 77, EAI decreased（P 〈 0.05） total amines concentration but increased skatole concentration in low-CP diet. On d 185, the EAI increased（P 〈 0.05） putrescine and total amines concentrations in low-CP diets but reduced（P 〈 0.05） in the normal-CP diets. The low-CP diet decreased the concentrations of these compounds.Conclusions： Collectively, these results indicate that EAI has short-term effects on the blood parameters and fecal microbial fermentation profile. The effects of EAI varied between CP levels, which was characterized by the significant alteration of glucose and putrescine concentration.

Dietary branched-chain amino acids modulate the dynamics of calcium absorption and reabsorption in proteinrestricted pigs

Background:Very low-protein(VLP)diets negatively impact calcium(Ca)metabolism and absorption.The objective of this study was to investigate the effect of supplemental branched-chain amino acids(BCAA)and limiting amino acids(LAA)on Ca digestibility,absorption and reabsorption in pigs fed with VLP diets.Forty-eight piglets were assigned to six treatments:positive control(PC),negative control(NC),and NC containing LAA 25%,LAA 50%,LAA+BCAA 25%(LB25)and LAA+BCAA 50%(LB50)more than recommendations.Results:Relative to PC or NC,LB25 and LB50 had higher digestibility of Ca and plasma Ca and phosphorus(P),but lower plasma vitamin D3.LB50 tended to increase vitamin D receptor transcript and protein in the gut,but decreased mRNA or protein abundance of parathyroid hormone 1 receptor(PTH1R),calbindin 1(CALB1),cytochrome P450 family 27 subfamily B member 1 and occludin in small intestine.LB50 increased the transcript of cytochrome P450 family 24 subfamily A member 1 and PTH1R but decreased the transcript of transient receptor potential cation channel subfamily V member 5,CALB1 and solute carrier family 17 member 4 in kidney.Conclusion:Overall,BCAA increased Ca digestibility through regulating the transcellular and paracellular Ca absorption in the gut and reabsorption in kidney during protein restriction.

乳清蛋白-果胶高内相乳液凝胶对低脂再制奶酪的品质影响

以乳清蛋白和果胶、葡聚糖为主要原料,采用酸诱导法制备乳清蛋白-果胶乳液凝胶(whey protein-pectin emulsion gel,WP)和乳清蛋白-葡聚糖乳液凝胶(whey protein-glucan emulsion gel,WG),比较35%、75%分散相体积分数凝胶(分别记为WP35、WG35、WP75、WG75)的功能特性,并进一步探究高内相乳液凝胶作为脂肪替代物在低脂再制奶酪中的代脂效果。结果表明:WP75的平均粒径最小,脂肪分布均匀,蛋白质网络结构稳定。乳液凝胶样品在0.1~10 Hz内弹性模量(G′)和黏性模量(G″)都随油相体积分数的升高呈上升趋势,其中WP75抵抗形变能力、热稳定性及持水性都优于其他样品。样品15%-WP75(添加WP75,脂肪质量分数15%的再制奶酪)油析性减弱,熔化性增强,质构特性与全脂对照无明显差异。研究表明乳清蛋白与果胶制备的高内相乳液凝胶在低脂奶酪产品有较好的脂肪替代效果,在低脂乳制品加工中具有良好的应用潜力。

Low crude protein diets supplemented with casein hydrolysate enhance the intestinal barrier function and decrease the pro-inflammatory cytokine expression in the small intestine of pigs

To reduce nitrogen excretion and lower feeding costs,low crude protein(CP)diets are sometimes pro-posed,however,a great reduction of dietary CP concentration(>4%reduction vs.recommended con-centration),even supplemented with essential and nonessential amino acids(AA)can detrimentally affect small intestinal barrier function and immunity,possibly due to the excessive lack of peptides.Here we hypothesize that with an extremely low CP concentration diet,protein-derived peptides,rather than AA supplementation,can improve intestinal barrier development and health.To test this hypothesis,21 growing pigs(19.90±1.00 kg body weight)were randomly assigned to 3 treatments with control diet(16%CP),or low CP diets(13%CP)supplemented with AA(LCPA)or casein hydrolysate(LCPC)for 28 days.In comparison with the control diet,the LCPA diet decreased the protein expression level of jejunal barrier factor zonula occludens-1(ZO-1)and stem cell proliferation factor leucine-rich repeat-containing G-protein-coupled receptor-5,whereas the LCPC diet enhanced intestinal barrier function by increasing the protein expression level of jejunal occludin and ZO-1 and ileal mucin-2.The LCPA diet reduced Lactobacillus counts,whereas the LCPC diet increased Lactobacillus counts and reduced Escherichia coli counts in the ileum.The LCPA diet also increased protein expression levels of pro-inflammatory cytokine interleukin-6(IL-6)and IL-22,whereas the LCPC diet decreased protein expression levels of pro-inflammatory IL-1β,IL-17A and tumor necrosis factor-αin the ileum.Collectively,the casein hydroly-sate supplementation of low CP diets showed beneficial effects on the small intestinal barrier,bacterial community,and immunity in pigs,pointing to the important role of protein-derived peptides in small intestinal health in cases of low crude protein diets.

Very low-protein diet to postpone renal failure: Pathophysiology and clinical applications in chronic kidney disease

The uremic syndrome is a metabolic disorder characterized by the impairment of renal handling of several solutes, the resulting accumulation of toxic products and the activation of some adaptive but detrimental mechanisms which all together contribute to the progression of renal damage. In moderate to advanced renal failure, the dietary manipulation of nutrients improves metabolic abnormalities and may contribute to delay the time of dialysis initiation. This commentary focuses on the physiopathological rationale and the clinical application of the very low-protein diet supplemented with ketoanalogs for the management of chronic kidney disease.