Excess Dietary Protein Research Articles

Identification of a leucine-mediated threshold effect governing macrophage mTOR signalling and cardiovascular risk.

High protein intake is common in western societies and is often promoted as part of a healthy lifestyle; however, amino-acid-mediated mammalian target of rapamycin (mTOR) signalling in macrophages has been implicated in the pathogenesis of ischaemic cardiovascular disease. In a series of clinical studies on male and female participants ( NCT03946774 and NCT03994367 ) that involved graded amounts of protein ingestion together with detailed plasma amino acid analysis and human monocyte/macrophage experiments, we identify leucine as the key activator of mTOR signalling in macrophages. We describe a threshold effect of high protein intake and circulating leucine on monocytes/macrophages wherein only protein in excess of ∼25 g per meal induces mTOR activation and functional effects. By designing specific diets modified in protein and leucine content representative of the intake in the general population, we confirm this threshold effect in mouse models and find ingestion of protein in excess of ∼22% of dietary energy requirements drives atherosclerosis in male mice. These data demonstrate a mechanistic basis for the adverse impact of excessive dietary protein on cardiovascular risk.

Effect of Different Coffee Brews on Tryptophan Metabolite-Induced Cytotoxicity in HT-29 Human Colon Cancer Cells.

Coffee consumption positively influences colon health. Conversely, high levels of tryptophan metabolites such as skatole released from intestinal putrefactive fermentation in the presence of excessive dietary animal protein intake, and gut microbiota alterations, may have several adverse effects, including the development of colorectal cancer. Therefore, this study aimed to elucidate the potential protective effects of coffee in the presence of different skatole levels. The results showed that skatole exposure induced reduced cell viability and oxidative stress in the HT-29 human colon cancer cell line. However, co-treatment of cells with skatole and coffee samples was able to reduce ROS production (up to 45% for espresso) compared to cells not treated with coffee. Real-time PCR analysis highlighted that treating HT-29 cells with skatole increased the levels of inflammatory cytokines and chemokines TNF-α, IL-1β, IL-8, and IL12, whereas exposure to coffee extracts in cells that were pretreated with skatole showed anti-inflammatory effects with decreased levels of these cytokines. These findings demonstrate that coffee may counteract the adverse effects of putrefactive compounds by modulating oxidative stress and exerting anti-inflammatory activity in colonocytes, thus suggesting that coffee intake could improve health conditions in the presence of altered intestinal microbiota metabolism.

An evaluation of the growth, blood biochemistry, hepatic glucose metabolism and hepatocyte apoptosis in the genetically improved farmed tilapia Oreochromis niloticus fed diets with distinct protein to corn starch ratios

This study was performed to evaluate the effects of dietary distinct protein to starch ratios on the growth, feed utilization, blood biochemistry, hepatic glucose metabolism and hepatocyte apoptosis of Nile tilapia Oreochromis niloticus. Three iso-lipidic (ca 6.56%) diets were formulated with elevated corn starch levels at the cost of protein provision, being designated as diets P40S5 (40.4% protein and 4.62% starch), P30S25 (30.4% protein and 24.2% starch) and P20S50 (19.9% protein and 48.6% starch). Tilapia juveniles (initial mean body weight, 32.0 g/fish) were assigned to 12 rectangular tanks (250 L each) with 20 fish per tank and fed the experimental diets to apparent satiation for 8 weeks. The results showed that either excess (40%) or insufficient (20%) amount of dietary protein impaired the growth of tilapia. Excess dietary protein led to unsatisfactory protein catabolism (lower protein efficiency ratio and protein productive value, and higher mRNA levels of hepatic glutamic-pyruvic transaminase 1 and glutamic-oxaloacetic transaminase paralogs), while insufficient amount of protein resulted in lower whole-body protein percentage. An increase in dietary starch from 5% or 25% to 50% was associated with enhanced lipid and glycogen storages in the liver of tilapia. Consistently, dietary starch reception up to 50% upregulated the expression of hepatic representative genes involved with glycolysis (glucokinase and phosphofructokinase muscle type a) and lipogenesis (acetyl-CoA carboxylase α and fatty acid synthase) while downregulated the expression of the gluconeogenic glucose-6-phosphatase catalytic subunit paralogs. TUNEL staining suggested that stronger apoptosis signal was recorded at the bile duct epithelium of the P20S50 fish. Concomitantly, plasma bile acid level nearly doubled, and an incidence (50%) of ‘green liver’ was observed in this treatment as compared with the P40S5 and P30S25 fish, indicating that bile acid metabolism disorder might be induced. Though plasma glucose (4.66–5.11 mmol/L) was not responsive to different treatments, advanced glycation end-products accumulated in the blood of the P20S50 fish, suggesting that 50% starch reception was probably associated with the progression of diabetes-associated pathologies. The overall results in this study suggested that tilapia might possess capability to tolerate dietary corn starch level up to 50% in a short-term exposure, whereas a long-term exposure might induce detrimental effects on liver functions.

Effects of dietary protein levels on growth performance, serum indexes, PI3K/AKT/mTOR/S6K signalling and intestinal microbiota of abalone Haliotis discus hannai

A 120-day feeding trial was conducted to assess the effect of dietary protein levels on growth performance, serum indexes, PI3 K/AKT/mTOR/S6 K signalling pathway and intestinal microbiota of abalone Haliotis discus hannai. Abalones (initial body weight: 15.88–16.54 g; initial shell length 41.70–42.40 mm) were fed nine isoenergetic (~16.08 kJ/g) and isolipidic (~42.0 g/kg) experimental diets with 93.5, 116.9, 151.1, 191.8, 230.3, 275.9, 320.3, 360.5 and 405.9 g/kg protein contents, respectively. Results showed that the optimal dietary protein level for H. discus hannai was determined as 259.4 g/kg through second-order polynomial regression analysis for weight gain rate (WGR). Serum TP and urea nitrogen levels were significantly increased when dietary protein levels were higher than 320.3 g/kg (p < .05). The highest gene expressions of phosphatidylinositol 3 kinase (PI3 K), target of rapamycin (mTOR) and ribosomal protein S6 kinase (S6 K) in muscle were found in the treatment with 275.9 g/kg of dietary protein. The excessive dietary protein level (405.9 g/kg) significantly decreased the gene expression of S6 K. Meanwhile, abalone fed with 275.9 g/kg of dietary protein exhibited the highest microbial diversity in intestine as measured by Chao richness and Shannon diversity index. In conclusion, dietary protein level reduced from 259.4 g/kg to 154.0 g/kg or increased from 259.4 to 323.0 g/kg, the WGR of abalone might be depressed with 5% likelihood. Over high (>360.5 g/kg) or low (<151.1 g/kg) dietary protein levels had negative effects on growth performance, serum indexes, PI3 K/AKT/mTOR/S6 K signalling and microbial diversity in intestine of abalone.

On-farm examination of sainfoin supplementation effects in dairy cows in a roughage-based feeding system: Indicators of protein utilisation

A case study was conducted with the objective to determine the effects of the tanniferous legume sainfoin (Onobrychis viciifolia) on protein utilisation of dairy cows, which were exposed to excessive dietary crude protein during autumn pasture grazing in a zero-concentrate feeding system. The study was conducted under practical conditions, deliberately accepting a certain lack of controllable variables. In order to assess a system applicable in practice, relatively small amounts of sainfoin were offered, and graded supply levels were compared by varying the duration of offer instead of dietary concentration. Within one dairy herd of 60 Swiss Fleckvieh cows, 30 individuals were chosen and randomly allocated to three groups balanced for milk yield, milk urea concentration, days in milk and parity. Over a period of 5 weeks, 2 kg per cow and day of sainfoin pellets were provided either intermittently, for 2 × 5 days (SST) in weeks 3 and 5 of the experiment or continuously over 35 days (SLT). A control group (CON) received 2 kg per cow and day of ryegrass pellets during the 5 weeks. The entire herd grazed on a protein-rich natural sward and was kept overnight in an open-space barn receiving fresh grass and hay ad libitum. Experimental pellets were offered individually twice per day in buckets. Feed, milk, faeces and urine samples were collected in weeks 0 (baseline), 3 and 5. Milk was analysed for fat, protein and urea, urine for purine derivatives, creatinine and nitrogen, and faeces for protein, fibre and particle fractions. During three sampling weeks, chewing activity was recorded by sensor halters. Treatment SST increased rumination time in the first half of the day, which was the only treatment effect on intake and rumination behaviour. Milk fat and protein yields were greater in SST compared to CON, but no treatment effect on concentration and yield of milk urea was found. The proportion of particle fractions in faeces was smaller in both sainfoin treatments compared to CON. In urine, the ratio of purine derivatives to creatinine tended to be higher in SST than in CON, and total urinary nitrogen excretion was lower, indicating a slightly better protein efficiency in SST. In summary, the study revealed small positive effects on protein metabolism and yield when sainfoin was applied short-term over two short periods, whereas long-term application had no effect.

A23 DIETARY PROTEIN AND AMINO ACID COMPOSITIONS INFLUENCE MICROBIOTA, INTESTINAL PERMEABILITY, AND SUSCEPTIBILITY TO COLITIS

Abstract Background Environmental factors, such as alterations in diet and microbiota, have been linked to inflammatory bowel diseases (IBD). The incidence of IBD is rising, particularly in Canada and other industrialized nations that consume western-style diets high in fat and protein. While most dietary proteins and amino acids are absorbed in the small intestine, substantial amounts can enter the colon for microbial metabolism and to exert effects on intestinal tissue and immune cells. Prospective cohort studies suggest that diets high in protein are associated with an increased risk of IBD. However, the role of excess dietary protein and amino acids in IBD pathogenesis is not clear. Aims To study whether and how consumption of diets high in protein or amino acids influences intestinal inflammation, colitis severity, and intestinal microbiota. Methods To assess the influence of dietary protein composition on colitis severity, specific pathogen-free C57BL/6 mice were fed isocaloric casein-based purified diets containing low (7%), normal (14%), or high (35%) protein (HPD). Mice were also fed an amino acid-defined diet (AAD) with amino acid and ingredient composition matched to the normal protein diet. Following three weeks of diet consumption ad libitum, mice were continued on the same diet and mucosal injury was induced with 2% dextran sulfate sodium (DSS; 5 days) followed by water (2 days) before sacrifice. Mice were monitored daily for clinical signs of colitis. Susceptibility to colitis was assessed by analysing stool consistency and blood, microscopic scoring (Cooper score), and by immunohistochemistry of colon tissue. Fecal microbiota (16S rRNA Illumina), intestinal permeability (Ussing chambers), proinflammatory gene expression (NanoString and RT-qPCR), and bacterial translocation (plating) were analysed. Results Following DSS exposure, mice fed HPD and AAD experienced greater weight loss, bacterial translocation to the spleen, stool blood, and diarrhea compared to mice fed the normal protein control diet. While all DSS-treated mice developed colitis, HPD and AAD fed mice also developed greater histologic damage, intestinal permeability, and innate immune cell infiltration. Cytokine profiling revealed that AAD is associated with significant up-regulation of IL-18 during colitis. Principle coordinates analysis based on Bray-Curtis dissimilarities demonstrates distinct shifts in the fecal microbiota of mice fed HPD and AAD. Conclusions These results suggest that excess dietary protein and amino acids are associated with more severe colitis and microbiota alterations in the DSS model. Previous studies demonstrate that IL-18 is up-regulated in IBD patients. Its overexpression may incite inflammation by stimulating cytokine signalling through NFκB and modify microbial community structure by regulating antimicrobial peptides. Funding Agencies CIHRFarncombe Family Digestive Health Research Institute, Douglas Family Chair in Gastroenterology Research

Over high or low dietary protein levels depressed the growth, TOR signaling, apoptosis, immune and anti-stress of abalone Haliotis discus hannai

A 120-day feeding trial was conducted to investigate the effects of relative higher and lower dietary protein levels on the growth, immunity and anti-stress of abalone Haliotis discus hannai fed diets with 17.64% (low), 30.49% (normal) and 43.27% (high) of proteins, respectively. The results showed that compared with 30.49% of dietary protein, 17.64% and 43.27% of dietary protein levels significantly decreased the weight gain rate and the activities of α-amylase, trypsin, alanine aminotransferase and aspartate aminotransferase in the hepatopancreas and serum of abalone (P < 0.05). Abalone fed 30.49% of dietary protein had the highest activity of superoxidase, acid phosphatase, alkaline phosphatase, lysozyme and the total anti-oxidative capacity, and the lowest content of malondialdehyde in the serum and hepatopancreas (P < 0.05). The gene expressions of TOR, S6k, Bcl-2, IκB, NfκB, TNF-α and Nrf2 were significantly up-regulated in the group with 30.49% of dietary protein (P < 0.05). Pathological abnormalities in hepatocyte cells of abalone were found in the groups with 17.64% and 43.27% of dietary protein. Meanwhile, accumulative mortalities of abalone after the Vibrio parahaemolyticus challenge test and heat stress test were significantly increased within these two groups (P < 0.05). In conclusion, the excessive (43.27) or deficient (17.64) dietary protein levels depressed the growth and immunity of abalone. Combined with the stress tests results, 17.63% or 43.27% of dietary protein contents are not recommended to the abalone facing the stress of vibriosis or high-water temperature (≥28 °C).

Graded supplementation of chestnut tannins to dairy cows fed protein-rich spring pasture: effects on indicators of protein utilization

An on-farm experiment was conducted in order to evaluate effects of graded supplementation with chestnut tannin extract to cows in situations of excessive dietary protein supply on a low-input organic dairy farm. Respectively 10 Swiss Fleckvieh cows received twice per day 1 kg of experimental pellets containing either 0, 50 or 100 g/kg of chestnut extract (targeted at approximately 0, 5 and 10 g extract/kg of total dietary dry matter). Experimental feeding lasted for 21 days. Measurements and collection of milk, faeces and urine spot samples were performed in weeks 0 (baseline), 1 and 3. All cows were kept in one herd on pasture; fresh grass and grass hay were provided in the barn during night. Milk yield was recorded and cows wore sensor halters for recording chewing activity. In urine, total nitrogen and purine derivatives were measured; faeces were analyzed for protein, fibre and particle fractions; in milk, solid concentrations were determined. The data was analyzed with a general linear model. Cows did not show differences in general eating and rumination behaviour, but needed time to accept the tannin-containing pellets. Milk yield and composition were not affected by treatment, except for lactose content. No relevant differences between treatments were found for urinary and faecal parameters. In conclusion, although technically easy to supplement, pellets containing chestnut tannin extract were not readily accepted by the cows and effects on protein digestion and metabolism were not found. Successful on-farm application of chestnut extract in order to improve nitrogen efficiency therefore seems questionable.

Serial Biomarkers of De Novo Lipogenesis Fatty Acids and Incident Heart Failure in Older Adults: The Cardiovascular Health Study.

BackgroundDe novo lipogenesis (DNL) is an endogenous pathway that converts excess dietary starch, sugar, protein, and alcohol into specific fatty acids (FAs). Although elevated DNL is linked to several metabolic abnormalities, little is known about how long‐term habitual levels and changes in levels of FAs in the DNL pathway relate to incident heart failure (HF).Methods and ResultsWe investigated whether habitual levels and changes in serial measures of FAs in the DNL pathway were associated with incident HF among 4249 participants free of HF at baseline. Plasma phospholipid FAs were measured at baseline, 6 years, and 13 years using gas chromatography, and risk factors for HF were measured using standardized methods. Incident HF was centrally adjudicated using medical records. We prospectively evaluated associations with HF risk of (1) habitual FA levels, using cumulative updating to assess long‐term exposure, and (2) changes in FA levels over time. During 22.1 years of follow‐up, 1304 HF cases occurred. After multivariable adjustment, habitual levels and changes in levels of palmitic acid (16:0) were positively associated with incident HF (interquintile hazard ratio [95% CI]=1.17 [1.00‐1.36] and 1.26 [1.03‐1.55], respectively). Changes in levels of 7‐hexadecenoic acid (16:1n‐9) and vaccenic acid (18:1n‐7) were each positively associated with risk of HF (1.36 [1.13‐1.62], and 1.43 [1.18‐1.72], respectively). Habitual levels and changes in levels of myristic acid (14:0), palmitoleic acid (16:1n‐7), stearic acid (18:0), and oleic acid (18:1n‐9) were not associated with incident HF.ConclusionsBoth habitual levels and changes in levels of 16:0 were positively associated with incident HF in older adults. Changes in 16:1n‐9 and 18:1n‐7 were also positively associated with incident HF. These findings support a potential role of DNL or these DNL‐related FAs in the development of HF.

Dietary protein reduction for Nile tilapia fingerlings reared in biofloc technology

AbstractThe objective of this study was to evaluate the growth performance of Nile tilapia fed diets with 28, 32, and 36% crude protein (CP) in biofloc technology (BFT) and to verify its influence on water quality and hematological parameters. The experimental design was completely randomized with three treatments (28, 32, and 36% CP) and six replicates. Nile tilapia (n = 270, 6.31 ± 0.40 g) were randomly distributed in 18 aquaria—200 L (15 fish/aquarium), over a period of 60 days. No differences (p &gt; .05) were observed among the treatments for the growth performance and hematological parameters. The volumes of nitrite and sedimentable solids showed higher values with 36% CP, which differed (p &lt; .05) in comparison to 28% CP. Different levels of dietary CP content (36, 32 and 28% CP) do not influence the growth performance and health of Nile tilapia (6–25 g) reared in BFT. Thus, an 8% reduction in dietary protein (28% CP) can generate savings in terms of the costs of production and can decrease the environmental impact of excess dietary protein.

Increased BUN and glucose in a group of San Cristóbal galapagos tortoises (Chelonoidis chathamensis)

Veterinary health examinations were performed on 19 captive tortoises in seminatural conditions at the ‘Galapaguera of Cerro Colorado’ and at the ‘Otoy Ranch’ on San Cristóbal Island, Galápagos. No abnormalities...

Interactions among morphotype, nutrition, and temperature impact fitness of an invasive fly.

Invasive animals depend on finding a balanced nutritional intake to colonize, survive, and reproduce in new environments. This can be especially challenging during situations of fluctuating cold temperatures and food scarcity, but phenotypic plasticity may offer an adaptive advantage during these periods. We examined how lifespan, fecundity, pre‐oviposition periods, and body nutrient contents were affected by dietary protein and carbohydrate (P:C) ratios at variable low temperatures in two morphs (winter morphs WM and summer morphs SM) of an invasive fly, Drosophila suzukii. The experimental conditions simulated early spring after overwintering and autumn, crucial periods for survival. At lower temperatures, post‐overwintering WM lived longer on carbohydrate‐only diets and had higher fecundity on low‐protein diets, but there was no difference in lifespan or fecundity among diets for SM. As temperatures increased, low‐protein diets resulted in higher fecundity without compromising lifespan, while high‐protein diets reduced lifespan and fecundity for both WM and SM. Both SM and WM receiving high‐protein diets had lower sugar, lipid, and glycogen (but similar protein) body contents compared to flies receiving low‐protein and carbohydrate‐only diets. This suggests that flies spend energy excreting excess dietary protein, thereby affecting lifespan and fecundity. Despite having to recover from nutrient depletion after an overwintering period, WM exhibited longer lifespan and higher fecundity than SM in favorable diets and temperatures. WM exposed to favorable low‐protein diet had higher body sugar, lipid, and protein body contents than SM, which is possibly linked to better performance. Although protein is essential for oogenesis, WM and SM flies receiving low‐protein diets did not have shorter pre‐oviposition periods compared to flies on carbohydrate‐only diets. Finding adequate carbohydrate sources to compensate protein intake is essential for the successful persistence of D. suzukii WM and SM populations during suboptimal temperatures.

Microbial nitrogen limitation in the mammalian large intestine.

Resource limitation is a fundamental factor governing the composition and function of ecological communities. However, the role of resource supply in structuring the intestinal microbiome has not been established and represents a challenge for mammals that rely on microbial symbionts for digestion: too little supply might starve the microbiome while too much supply might starve the host. Here, we present evidence that microbiota occupy a habitat limited in total nitrogen supply within the large intestines of 30 mammal species. Furthermore, lowering dietary protein levels in mice reduced bacterial fecal concentrations. A gradient of stoichiometry along the length of the gut was consistent with the hypothesis that intestinal nitrogen limitation results from host absorption of dietary nutrients. Nitrogen availability though is also likely shaped by host-microbe interactions: levels of host-secreted nitrogen were altered in germfree mice and when bacterial loads were reduced via experimental antibiotic treatment. Single-cell spectrometry revealed that members of the phylum Bacteroidetes consumed nitrogen in the large intestine more readily than other commensal taxa. Collectively, our findings support a model where nitrogen limitation arises from preferential host utilization of dietary nutrients, and we speculate that this resource limitation could enable hosts to regulate microbial communities in the large intestine. Furthermore, commensal microbiota may have adapted to nitrogen-limited settings, suggesting why excess dietary protein has been associated with degraded gut microbial ecosystems.

Retro-engineering the protein sparing effect to preserve n-3 LC-PUFA from catabolism and optimise fish oil utilisation: A preliminary case study on juvenile Atlantic salmon

Protein has historically been the more expensive macronutrient in aquafeeds. In consideration of this, the implementation of high energy diets for increased protein utilisation is common in modern day aquafeed formulations, evoking what is widely coined as the “protein sparing effect”. However, market forces are changing the cost and availability of raw materials, and oils are now as expensive, if not more expensive, than most protein sources. In light of this, the current study looked to retro-engineer the “protein sparing effect” to test the hypothesis that dietary lipids (in particular omega-3 long chain polyunsaturated fatty acids; n-3 LC-PUFA) could be spared from catabolism by the provision of a high protein diet, manifesting in a more efficient retention/utilisation of these health promoting fatty acids. As such, a case study was implemented in which Atlantic salmon (Salmo salar) were fed a series of iso-energetic diets containing a sliding ratio of dietary protein to lipid, and a fixed concentration of n-3 LC-PUFA. Specifically, these experimental diets were achieved by keeping a constant inclusion of marine derived raw materials (fish meal and fish oil), and varying the relative inclusion of animal by-products (meat and bone meal, blood meal and tallow). Growth performance and feed utilisation parameters as well as tissue fatty acid composition and apparent fatty acid metabolism were assessed. Despite the varying proximate composition of the experimental diets, no significant differences were evident in growth or tissue proximate parameters. Likewise, no conclusive differences were apparent between treatments in relation to the concentration of n-3 LC-PUFA in fillet and whole body samples. However, a remarkable sparing of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) from catabolism was apparent and most certainly attributable to 1) the reduced dietary supply of these nutrients, and 2) the preferential utilisation of excess dietary protein for energy production. The results achieved by this study were not conclusive, and the hypothesis cannot be accepted or rejected, but some promising indications have been obtained, ultimately requiring further in-depth investigation. Statement of relevanceThis study documents the effects of feeding a sliding protein to lipid ratio in diets for juvenile Atlantic salmon on potential n-3 LC-PUFA sparing. Essentially, given the rising costs of oil sources in aquafeeds we have ‘retro-engineered’ the protein sparing effect and developed a new approach for consideration in sustainable feed development.

Short communication: Urea induces T helper 2 (Th2) type environment at transcriptional level and prostaglandin E2 secretion in bovine oviduct epithelial cells in culture

Excess dietary protein intake in early lactation dairy cows resulting in blood urea nitrogen of greater than 19 to 20mg/dL is associated with decreased fertility. Little is known about the local interference of urea in the normal immunological environment of the oviduct that provides optimal conditions for early reproductive events. A bovine oviduct epithelial cell (BOEC) culture was used to determine how urea influences immune environment. The BOEC monolayer was supplemented with low (20mg/dL) and high (40mg/dL) concentrations of urea together with ovarian steroids, estradiol (1ng/mL) and progesterone (1ng/mL), and LH (10ng/mL) at concentrations observed during the preovulatory period. The urea values used in this study were equivalent to 9.3 and 18.7mg/dL of blood urea nitrogen, which are typically common in lactating dairy cows with low or high protein intake, respectively. Stimulation of BOEC with 40mg/dL of urea induced gene expression of IL10 and IL4, epithelial-derived T helper type 2-driving (anti-inflammatory) cytokines as well as mPGES-1 expression and prostaglandin E2 (PGE2) secretion. However, urea concentrations of both 20 and 40mg/dL failed to alter the expression of IL1B and TNFA, Th1-driving cytokines, and the gene expression of TLR4. However, a concentration of 40mg/dL of urea stimulated α 1-acid glycoprotein expression, an acute phase protein. Data from this in vitro study suggest that urea, at least in part, contributes to influence the expression of some immune-related genes toward T helper type 2 type and prostaglandin E2 secretion, leading to disruption in local environment for fertilization and early embryonic development.

Influence of excessive dietary protein intake during late gestation on drylot beef cow performance and progeny growth, carcass characteristics, and plasma glucose and insulin concentrations.

Spring-calving cows ( = 49) were used to investigate the effects of excessive prepartum dietary protein intake on late gestation cow performance as well as subsequent progeny growth, carcass characteristics, and plasma glucose and insulin concentrations. Treatments were formulated to be isocaloric and provide 100% (REQ) or 129% (HP) of CP requirement. Treatments were limit-fed 78 ± 12 d prepartum to calving. All cows were fed a common diet postpartum. Cow BW and BCS were recorded at initiation of treatments and within 48 h post-calving. Milk production was estimated via the weigh-suckle-weigh technique 69 ± 11 d postpartum. Calf BW was measured at birth and at weaning (121 ± 11 d of age). Progeny ( = 42) were weaned as a group and placed into a feedlot and fed a common finishing diet. Glucose and insulin concentrations were analyzed on a subset of progeny (12 per treatment) 90, 120, 150, 180, 210, and 240 min post-feeding, 2 d before slaughter (342 ± 11 d of age). Treatment had no effect ( ≥ 0.22) on cow BW, BCS, milk production, and subsequent reproduction or progeny preweaning growth. Progeny finishing growth and marbling scores were not affected ( ≥ 0.24) by treatment, yet 12th rib fat thickness ( < 0.01), KPH ( = 0.04), and YG ( = 0.01) were greater for progeny born to HP dams. Progeny born to HP dams had decreased ( ≤ 0.01) glucose and insulin concentrations, and insulin to glucose ratios, indicating greater insulin sensitivity. Although feeding cows 129% of CP requirement during late gestation did not affect cow performance or progeny preweaning or finishing period growth; carcass adiposity was increased by maternal treatment.

Healthy pregnant women in Canada are consuming more dietary protein at 16- and 36-week gestation than currently recommended by the Dietary Reference Intakes, primarily from dairy food sources

Adequate dietary protein intake throughout pregnancy is essential to ensure healthy fetal development. Insufficient and excessive maternal dietary protein intakes are both associated with intrauterine growth restriction, resulting in low birth weight infants. The aim of this study was to analyze the dietary protein intake patterns of healthy pregnant women in Vancouver, British Columbia, during early and late gestation. We hypothesized that women would be consuming higher protein during late stages of pregnancy compared with early stages of pregnancy. Interviewer-administered food frequency questionnaires were collected prospectively from 270 women at 16- and 36-week gestation; food frequency questionnaires from 212 women met study criteria. Maternal anthropometrics at both stages and infant weight at birth were collected. Wilcoxon signed rank tests were used to determine significant gestational differences in protein intakes. Spearman correlation was used to determine the influence of protein intakes and maternal anthropometrics on pregnancy outcomes. Median (25th and 75th percentiles) protein intakes adjusted for body weight were 1.5 (1.18 and 1.79) and 1.3 (1.04 and 1.60) g/kg per day at 16- than 36-week gestation, respectively. Primary protein sources were identified as dairy products. Protein intakes were negatively correlated with birth weight (P < .05), whereas maternal height, weight, body mass index, and weight gain to 36-week gestation were positively correlated with birth weight (P < .05). This study provides current dietary protein intake patterns among healthy Canadian women during pregnancy and indicates higher intakes than current Dietary Reference Intakes recommended dietary allowance of 1.1 g/kg per day, especially during early gestation.

A new diet for autosomal dominant polycystic kidney disease (381.1)

Background: Recent studies indicate Autosomal Dominant Polycystic Kidney Disease (ADPKD) progression is hastened by excess dietary protein, salt, and dietary acids, and slowed by increased water intake. The aim of this study is to determine the extent to which the Kansas PKD diet can control these factors.Methods: Six adults with ADPKD at the University of Kansas Medical Center Kidney Clinic were enrolled. Participants followed their usual diet for one week and the Kansas PKD diet for the following 4 weeks. Changes in dietary protein, salt and net endogenous acid production (NEAP) were assessed from diet records and changes in osmolality, sodium, urea, and net acid excretion were calculated by averaging 24‐hour urine collections taken at each visit, baseline (day 8) and study end (day 36).Results: The Kansas PKD diet resulted in individuals having decreases in dietary protein (‐27%) and sodium (‐40%), NEAP (‐104%), urine osmolality (‐25%), urinary sodium excretion (‐29%), urea (‐17%), and net acid excretion (‐34%) on day 36.Conclusion: This pilot study demonstrated beneficial changes in the dietary factors known to affect ADPKD progression. Future studies will evaluate structural and functional changes in the kidney while following the Kansas PKD diet and participant acceptability in a larger sample.Key Words: Polycystic Kidney Disease, diet, nutrition, dietary acidsGrant Funding Source: Supported by the University of Kansas Medical Center Kidney Institute and Frontiers Pilot StudyGrant

Reducing dietary protein in dairy cow diets: implications for nitrogen utilization, milk production, welfare and fertility

In light of increasing global protein prices and with the need to reduce environmental impact of contemporary systems of milk production, the current review seeks to assess the feasibility of reducing levels of dietary CP in dairy cow diets. At CP levels between 140 and 220 g/kg DM there is a strong positive relationship between CP concentration and dry matter intake (DMI). However, such effects are modest and reductions in DMI when dietary CP is below 180 g/kg DM can be at least partially offset by improving the digestibility and amino acid profile of the undegradable protein (UDP) component of the diet or by increasing rumen fermentable energy. Level and balance of intestinally absorbable amino acids, in particular methionine and lysine, may become limiting at lower CP concentrations. In general the amino acid composition of microbial protein is superior to that of UDP, so that dietary strategies that aim to promote microbial protein synthesis in the rumen may go some way to correcting for amino acid imbalances in low CP diets. For example, reducing the level of NDF, while increasing the proportion of starch, can lead to improvements in nitrogen (N) utilisation as great as that achieved by reducing dietary CP to below 150 g/kg. A systematic review and meta-analysis of responses to rumen protected forms of methionine and lysine was conducted for early/mid lactation cows fed diets containing ⩽150 g CP/kg DM. This analysis revealed a small but significant (P=0.002) increase in milk protein yield when cows were supplemented with these rumen protected amino acids. Variation in milk and milk protein yield responses between studies was not random but due to differences in diet composition between studies. Cows fed low CP diets can respond to supplemental methionine and lysine so long as DMI is not limiting, metabolisable protein (MP) is not grossly deficient and other amino acids such as histidine and leucine do not become rate limiting. Whereas excess dietary protein can impair reproduction and can contribute to lameness, there is no evidence to indicate that reducing dietary CP levels to around 140 to 150 g CP/kg DM will have any detrimental effect on either cow fertility or health. Contemporary models that estimate MP requirements of dairy cows may require refinement and further validation in order to predict responses with low CP diets.

Chapter 34 - Hepatic encephalopathy in alcoholic cirrhosis

Hepatic encephalopathy (HE) is a serious neuropsychiatric complication of cirrhosis in alcoholic patients that is characterized clinically by personality changes, sleep abnormalities, and impaired motor coordination, as well as cognitive dysfunction progressing to stupor and coma. Procedures used for diagnosis and grading of HE include neurologic assessment, electroencephalography, psychometric testing, and use of the critical flicker frequency test. Neuropathologically, HE in cirrhosis is principally a disorder of neuroglia characterized by Alzheimer type II astrocytosis and activation of microglia. However, thalamic and cerebellar neuronal pathologies have been noted as well as lesions to globus pallidus and substantia nigra, leading to a condition known as "parkinsonism in cirrhosis." Multiple mechanisms have been proposed to account for the pathogenesis of HE in cirrhosis, including the neurotoxic actions of ammonia and manganese (normally removed via the hepatobiliary route), impaired brain energy metabolism, central proinflammatory mechanisms, and alterations of both excitatory and inhibitory neurotransmission. Treatment of HE in cirrhosis continues to rely on ammonia-lowering strategies such as lactulose, antibiotics, probiotics and l-ornithine l-aspartate with nutritional management consisting of adequate (but not excessive) dietary protein and vitamin B1 supplements. l-DOPA may improve parkinsonian symptoms. Liver transplantation leads to recovery of central nervous system function in the majority of cases.