Effects of Amino Acid Supplementation to a Low-Protein Diet on the Growth Performance and Protein Metabolism-related Factors in Broiler Chicks.

A low-protein (LP) diet may alleviate the environmental impact of chicken meat production by reducing nitrogen excretion and ammonia emissions. Thus, this study investigated the effect of a 15% reduced protein diet with or without amino acid (AA) supplementation on the growth performance of broiler chicks from 10 to 35 days of age and the underlying mechanism for loss of skeletal muscle mass. Thirty-six male broiler chicks were allocated to three experimental groups based on body weight: control, LP, and essential AA-supplemented LP (LP+AA). The body weight gain, feed conversion ratio, and weight of breast muscles and legs significantly decreased only in the LP group at the end of the feeding period. Plasma uric acid levels were significantly lower in the LP+AA group than those of the other groups. In the LP group, mRNA levels of microtubule-associated protein 1 light chain 3 isoform B were significantly higher in the pectoralis major, whereas those of atrogin-1, muscle RING-finger protein-1, and myoblast determination protein 1 were significantly higher in the biceps femoris compared to those in the control group. There were no significant differences in insulin-like growth factor 1 mRNA levels in the liver or skeletal muscle between groups. These findings suggested that supplementation with essential AAs ameliorated the impaired effects of an LP diet on growth performance in broiler chicks, and that the transcriptional changes in proteolytic genes in skeletal muscles might be related to the impaired effects of the LP diet.

Effects of improved amino acid balance diet on lysine mammary utilization, whole body protein turnover and muscle protein breakdown on lactating sows.

BACKGROUND: The study objective was to test the hypothesis that low crude protein (CP) diet with crystalline amino acids (CAA) supplementation improves Lys utilization efficiency for milk production and reduces protein turnover and muscle protein breakdown. Eighteen lactating multiparous Yorkshire sows were allotted to 1 of 2 isocaloric diets (10.80 MJ/kg net energy): control (CON; 19.24% CP) and reduced CP with "optimal" AA profile (OPT; 14.00% CP). Sow body weight and backfat were recorded on d 1 and 21 of lactation and piglets were weighed on d 1, 14, 18, and 21 of lactation. Between d 14 and 18, a subset of 9 sows (CON = 4, OPT = 5) was infused with a mixed solution of 3-[methyl-2H3]histidine (bolus injection) and [13C]bicarbonate (priming dose) first, then a constant 2-h [13C]bicarbonate infusion followed by a 6-h primed constant [1-13C]lysine infusion. Serial blood and milk sampling were performed to determine plasma and milk Lys enrichment, Lys oxidation rate, whole body protein turnover, and muscle protein breakdown. RESULTS: Over the 21-d lactation period, compared to CON, sows fed OPT had greater litter growth rate (P < 0.05). Compared to CON, sows fed OPT had greater efficiency of Lys (P < 0.05), Lys mammary flux (P < 0.01) and whole-body protein turnover efficiency (P < 0.05). Compared to CON, sows fed OPT tended to have lower whole body protein breakdown rate (P = 0.069). Muscle protein breakdown rate did not differ between OPT and CON (P = 0.197). CONCLUSION: Feeding an improved AA balance diet increased efficiency of Lys and reduced whole-body protein turnover and protein breakdown. These results imply that the lower maternal N retention observed in lactating sows fed improved AA balance diets in previous studies may be a result of greater partitioning of AA towards milk rather than greater body protein breakdown.

Low-Protein Diets Differentially Regulate Energy Balance during Thermoneutral and Heat Stress in Cobb Broiler Chicken (Gallus domesticus).

The objective was to assess whether low-protein (LP) diets regulate food intake (FI) and thermogenesis differently during thermoneutral (TN) and heat stress (HS) conditions. Two-hundred-day-old male broiler chicks were weight-matched and assigned to 36 pens with 5-6 chicks/pen. After 2 weeks of acclimation, birds were subjected into four groups (9 pens/group) including (1) a normal-protein diet under TN (ambient temperature), (2) an LP diet under TN, (3) a normal-protein diet under HS (35 °C for 7 h/day), and (4) an LP diet under HS, for 4 weeks. During HS, but not TN, LP tended to decrease FI, which might be associated with a lower mRNA abundance of duodenal ghrelin and higher GIP during HS. The LP group had a higher thermal radiation than NP under TN, but during HS, the LP group had a lower thermal radiation than NP. This was linked with higher a transcript of muscle ß1AR and AMPKα1 during TN, but not HS. Further, LP increased the gene expression of COX IV during TN but reduced COX IV and the sirtuin 1 abundance during HS. The dietary protein content differentially impacted plasma metabolome during TN and HS with divergent changes in amino acids such as tyrosine and tryptophan. Compared to NP, LP had increased abundances of p_Tenericutes, c_Mollicutes, c_Mollicutes_RF9, and f_tachnospiraceae under HS. Overall, LP diets may mitigate the negative outcome of heat stress on the survivability of birds by reducing FI and heat production. The differential effect of an LP diet on energy balance during TN and HS is likely regulated by gut and skeletal muscle and alterations in plasma metabolites and cecal microbiota.

Effect of Low Protein Diet on Bone Structure of Young Wistar Mice.

<b>Background and Objective:</b> Malnutrition and stunting are major unresolved problems in Indonesia. Protein deficiency can cause stunted growth, as well as make physical and cognitive abilities cannot reach their maximum potential. During childhood the need for protein must be fulfilled so that the peak of bone formation during adolescence can be perfect. In malnourished children, a low protein diet will lead to thinning of the bone cortex. Due to the high rate of stunting and malnutrition in children due to protein deficiency, a study was conducted on the effects of feeding low protein diet on rat bones. <b>Materials and Methods:</b> Male Wistar rats (n = 10) at 6-8 weeks old (body weight around 250 g), control groups were fed a normal chow diet and low protein diet groups were given low protein chow diet (protein 5%) for 18 weeks, then the rats were sacrificed and the femoral bones were isolated. Body weight, femur weight, femur length were checked and bone density was examined using X-ray. <b>Results:</b> The body proportions of the low protein group rats were smaller and thinner than those of the control group. This difference is supported by the significant weight loss starting from the sixth week after low protein feeding. There are significant differences in body weight and femur weight between the control and low protein diet groups. Bone density decreases significantly in low protein diet group. Macroscopically, the femur length of the low protein group was shorter than the control group, however the femur length did not show significant differences statistically between the two groups. <b>Conclusion:</b> A low protein diet decreased the body weight of the rats, also causing impaired bone growth characterized by decreasing femur weight. The low protein diet also caused osteoporosis in the bones.

The transgenerational effects of maternal low-protein diet during lactation on offspring.

Environment factors such as diet and lifestyle can influence the health of both mothers and offspring. However, its transgenerational transmission and underlying mechanisms remain largely unknown. Here, using a maternal lactation-period low-protein diet (LPD) mouse model, we show that maternal LPD during lactation causes decreased survival and stunted growth, significantly reduces ovulation and litter size, and alters the gut microbiome in the female LPD-F1 offspring. The transcriptome of LPD-F1 metaphase II (MII) oocytes shows that differentially expressed genes are enriched in female pregnancy and multiple metabolic processes. Moreover, maternal LPD causes early stunted growth and impairs metabolic health, which is transmitted for two generations. The methylome alteration of LPD-F1 oocytes can be partly transmitted to the F2 oocytes. Together, our results reveal that LPD during lactation transgenerationally affects offspring health, probably via oocyte epigenetic changes.

Growth performance and nitrogen excretion of broiler chickens fed low protein diets supplemented with crystalline amino acids.

This study was conducted to determine the effects of amino acid (AA) supplementation in low-protein (LP) diets on growth performance and nitrogen (N) excretion. A total of 175 7-day-old Ross 308 male broilers, with a mean body weight (BW) of 165 g (standard deviation = 11.2 g), were grouped into five blocks by BW and allocated to seven treatments according to a randomized complete block design with five replicate cages at five birds per cage. Dietary treatments comprised a control diet containing 20.0% crude protein (CP) and six LP diets containing either 18.5% or 17.0% CP. These LP diets were supplemented with either no AA supplementation, indispensable AA, or both indispensable and dispensable AA (glutamic acid and glycine). Birds were fed experimental grower diets from day 7 to 21 and then commercial finisher diets until day 28. During the grower period (day 7 to 21), birds fed LP diets supplemented with indispensable AA exhibited greater (p < 0.05) BW, body weight gain (BWG), feed intake (FI), and gain-to-feed ratio (G:F) than birds fed LP diets without crystalline AA and were comparable to birds fed the control diet. During the finisher period (day 21 to 28), birds fed LP diets supplemented with indispensable AA showed greater (p < 0.05) BW than birds fed LP diets without crystalline AA, and their growth performance was comparable to birds fed the control diet. Throughout the overall period, supplementing indispensable AA in LP diets resulted in elevated (p < 0.05) BWG, FI, and G:F more than those of LP diets without crystalline AA and were comparable to those of the control diet. Supplementing indispensable AA in LP diets decreased amount and coefficient of N excretion as much as the control diet. Dispensable AA supplementation in LP diets did not influence growth performance and N excretion. In conclusion, supplementing indispensable AA in LP diets maintains growth performance and N excretion until the dietary CP lowers from 20.0% to 17.0% during the grower period. As long as dietary CP is above 17.0%, dispensable AA may not be deficient in LP diets during the grower period.

The Use of Diets in the Diagnosis and Treatment of Common Gastrointestinal Diseases in Dogs and Cats.

The nutritional health of dogs and cats is important to pet owners around the world. Nutrition is inextricably linked to the health of the gastrointestinal system and vice versa. Gastrointestinal signs, such as vomiting, diarrhea, anorexia, or weight loss, are one of the most common reasons that dog and cat owners make non-routine appointments with veterinarians. Those patients are evaluated systematically to identify and/or rule out the causes of the symptoms. Some causes of chronic diarrhea are within the gastrointestinal tract while others are secondary to pathogenic factors outside the digestive system. Some useful biomarkers of chronic intestinal disease (enteropathy) exist in serum and feces. After determination that the clinical signs are due to primary gastrointestinal disease and that there is no parasitism, specific diets are used for at least two weeks. There are several types of diets for pets with chronic enteropathies. There are limited ingredient diets and hydrolyzed protein diets with reduced levels of allergens. There are also highly digestible and fiber-enhanced diets. Some diets contain probiotics and/or prebiotics. If symptoms do not improve and the patient is stable, a diet from a different class may be tried. For chronic enteropathies, the prognosis is generally good for symptom resolution or at least improvement. However, if interventions with novel diets do not ameliorate the symptoms of chronic enteropathy, then antibiotic, anti-inflammatory, or immunosuppressant therapy or further, more invasive diagnostics such as taking an intestinal biopsy, may be indicated. Pancreatitis is a common gastrointestinal disease in dogs and cats and patients may present with mild to severe disease. Many patients with mild to moderate disease can be successfully treated with early supportive care, including feeding a low-fat diet. A novel pharmaceutical, fuzapladib (Panoquell-CA1) looks very promising for treating more severe forms of acute pancreatitis in dogs. Maintenance on a low-fat diet may prevent pancreatitis in at-risk dogs. Future advances in medicine will allow pet owners and veterinarians to use dietary management to maximize the health of their dogs and cats.

Dietary cysteine and methionine promote peroxisome elevation and fat loss by induction of CG33474 expression in Drosophila adipose tissue.

The high-protein diet (HPD) has emerged as a potent dietary approach to curb obesity. Peroxisome, a highly malleable organelle, adapts to nutritional changes to maintain homeostasis by remodeling its structure, composition, and quantity. However, the impact of HPD on peroxisomes and the underlying mechanism remains elusive. Using Drosophila melanogaster as a model system, we discovered that HPD specifically increases peroxisome levels within the adipose tissues. This HPD-induced peroxisome elevation is attributed to cysteine and methionine by triggering the expression of CG33474, a fly homolog of mammalian PEX11G. Both the overexpression of Drosophila CG33474 and human PEX11G result in increased peroxisome size. In addition, cysteine and methionine diets both reduce lipid contents, a process that depends on the presence of CG33474. Furthermore, CG33474 stimulates the breakdown of neutral lipids in a cell-autonomous manner. Moreover, the expression of CG33474 triggered by cysteine and methionine requires TOR signaling. Finally, we found that CG33474 promotes inter-organelle contacts between peroxisomes and lipid droplets (LDs), which might be a potential mechanism for CG33474-induced fat loss. In summary, our findings demonstrate that CG33474/PEX11G may serve as an essential molecular bridge linking HPD to peroxisome dynamics and lipid metabolism.

Effects of different dietary threonine and glycine supplies in broilers fed low-protein diets.

The reduction of crude protein (CP) content of broiler diets with balanced amino acid supply can increase the nitrogen (N) utilization efficiency and reduce ammonia emission, the risk of many health problems in birds. Feeding low protein (LP) diets without the impairment of performance traits needs the optimized dietary levels of threonine (Thr) and the non-essential amino acid (AA) glycine (Gly) and serine (Ser). However, the required concentrations and interactions of Thr and Gly + Ser, expressed as Gly equivalent (Glyequi), in LP diets are not fully understood. Therefore, the aim of this study was to investigate the effects of three LP (LP1-3) grower (11-24 days) and finisher (25-35 days) diets with 2% CP reduction compared to the control (C), differing in standardized ileal digestible (SID) Thr to lysine (Lys) ratio (C, LP1, LP3: 63%, LP2: 72%) and Glyequi levels (C: 15.65 g/kg, LP1: 13.74 g/kg, LP2: 13.70 g/kg, LP3: 15.77). The LP treatments did not impair the performance traits of broilers. The LP2 treatment with increased SID Thr-to-Lys ratio (+9.0%) resulted in significantly higher body weight gain and a more advantageous feed conversion ratio in the whole fattening compared to the control treatment with normal CP level (p < 0.05). The LP3 treatment containing swine meat meal with similar Glyequi levels compared to the normal CP treatment led to the most advantageous feed conversion ratio in the finisher phase and the highest nitrogen retention efficiency (p < 0.05). However, the LP3 treatment with a high starch-to-CP ratio negatively influenced the relative carcass weight and the ratio of abdominal fat of broilers (p < 0.05).

Plant-based diets in patients with chronic kidney disease.

Dietary protein restriction has been considered to be a nutritional-related strategy to reduce risk for end-stage kidney disease among patients with non-dialysis-dependent chronic kidney disease (CKD). However, there is insufficient evidence to recommend a particular type of protein to slow down the CKD progression. Recently, various plant-based diets could demonstrate some additional benefits such as a blood pressure-lowering effect, a reduction of metabolic acidosis as well as hyperphosphatemia, and gut-derived uremic toxins. Furthermore, the former concerns about the risk of undernutrition and hyperkalemia observed with plant-based diets may be inconsistent in real clinical practice. In this review, we summarize the current evidence of the proposed pleiotropic effects of plant-based diets and their associations with clinical outcomes among pre-dialysis CKD patients.

A maternal low-protein diet impaired glucose metabolism and altered the lncRNA profiles of islets in adult offspring.

A maternal low-protein diet during pregnancy can increase children's susceptibility to diabetes mellitus in adulthood. However, whether long noncoding RNAs (lncRNAs) in islets participate in the development of diabetes in adult offspring following maternal protein restriction is not fully understood. Female mice were fed a low-protein (LP) diet or control diet throughout gestation and lactation. The male offspring were then randomly divided into two groups according to maternal diet: offspring from control diet group dams (Ctrl group) and offspring from LP group dams (LP group). We observed the glucose metabolism of adult offspring. A lncRNA microarray was constructed for the islets from the LP group and Ctrl group to explore the differently expressed lncRNAs. Gene ontology enrichment and Kyoto Encyclopedia of Genes and Genomes analyses were subsequently used to predict the functions of the differently expressed lncRNAs. The body weight from birth to 12 weeks of age was significantly lower in the LP offspring. Adult LP offspring exhibited impaired glucose tolerance and decreased insulin secretion, consistent with the reduction in ß-cell proliferation. According to the lncRNA microarray, four lncRNAs, three upregulated lncRNAs, and one downregulated lncRNA were differently expressed in LP offspring islets compared with Ctrl offspring. Gene ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses revealed that these differentially expressed lncRNAs were mostly associated with the hypoxia-inducible factor-1α signaling pathway. Additionally, we validated the expression of these four differentially expressed lncRNAs via quantitative real-time polymerase chain reaction. Our findings demonstrated the expression patterns of lncRNAs in islets from adult offspring of mothers who consumed a maternal low-protein diet.

Dietary crude protein time-dependently modulates the bacterial community and metabolites and changes dietary nutrient efficiency in growing pigs.

The reduced nutrient digestibility of low-protein (LP) diets has been shown to be caused by the weakened fermentative capacity of the post-gut flora. The dynamic regulation of dietary protein contents on post-gut microbial population and fermentative metabolism is unclear. Twelve growing barrows (19.9 ± 0.8 kg) fitted with a T-cannula at the blind end of the cecum were randomly administered a high-protein (HP, 21.5% crude protein [CP]) diet or an LP (15.5% CP) diet for 28 d. The cecal content and feces were collected at d 1, 14, and 28 of the experiment for microflora structures and metabolite concentrations analysis. The nutrient digestibility coefficient and plasma biochemical parameters were also determined. Compared with the HP treatment, the LP treatment showed decreased plasma urea nitrogen concentration and apparent total tract digestibility of dry matter, gross energy, and CP (P < 0.01). In addition, urinary nitrogen losses, total nitrogen losses, and daily nitrogen retention in the LP treatment were lower than those in the HP treatment (P < 0.01), and the nitrogen retention-to-nitrogen intake ratio in the LP treatment was increased (P < 0.01). The HP group showed increased cecal total short-chain fatty acids (SCFA) concentration and fecal propionate, butyrate, and total SCFA concentrations (P < 0.05) on d 14 and 28, which may be mainly related to the elevated abundance of SCFA-producing bacteria, such as Ruminococcus, Lactobacillus, and Prevotella (P < 0.05). Probiotics, such as Bifidobacterium, Bacteroidales S24-7, and Rikenella, enriched in the LP treatment possibly contributed to reduced plasma endotoxin content. The differences in the abundances of almost all the above-mentioned flora appeared on d 28 but not d 14. Likewise, differences in the Simpson and Shannon indices and clustering patterns of the microbiota between treatments were also only observed on d 28. To sum up, in a time-dependent manner, the LP diet increased probiotics with gut-improving functions and decreased SCFA-producing bacteria, which may cause enhanced intestine health and reduced nutrient digestibility.

Effects of Dietary Intervention on Nutritional Status in Elderly Individuals with Chronic Kidney Disease.

The prevalence of chronic kidney disease (CKD) is rising, especially in elderly individuals. The overlap between CKD and aging is associated with body composition modification, metabolic abnormalities, and malnutrition. Renal care guidelines suggest treating CKD patient with a low-protein diet according to the renal disease stage. On the other hand, geriatric care guidelines underline the need for a higher protein intake to prevent malnutrition. The challenge remains of how to reconcile a low dietary protein intake with insuring a favorable nutritional status in geriatric CKD populations. Therefore, this study aims to evaluate the effect of a low-protein adequate energy intake (LPAE) diet on nutritional risk and nutritional status among elderly CKD (stage 3-5) patients and then to assess its impact on CKD metabolic abnormalities. To this purpose, 42 subjects [age ≥ 65, CKD stage 3-5 in conservative therapy, and Geriatric Nutritional Risk Index (GNRI) ≥ 98] were recruited and the LPAE diet was prescribed. At baseline and after 6 months of the LPAE diet, the following data were collected: age, sex, biochemical parameters, anthropometric measurements, body composition, and the GNRI. According to their dietary compliance, the subjects were divided into groups: compliant and non-compliant. For the compliant group, the results obtained show no increased malnutrition risk incidence but, rather, an improvement in body composition and metabolic parameters, suggesting that the LPAE diet can provide a safe tool in geriatric CKD patients.

The effects of protein intake higher than the recommended value on body composition changes after bariatric surgery: A meta-analysis of randomized controlled trials.

BACKGROUND & AIMS: There is a lack of a meta-analysis to comprehensively assess the effectiveness of higher protein intake in addition to the recommended value on body composition post-bariatric surgery. We aimed to perform a meta-analysis of randomized controlled trials to determine the effects of protein intake higher than the recommended value on body composition changes after bariatric surgery. METHODS: Electronic databases, including Scopus, PubMed/Medline, and Web of Sciences, were searched until July 2023. Studies that assessed the effect of protein intake higher than the recommended value on postoperative body composition, i.e., weight, body mass index (BMI), fat mass (FM), fat-free mass (FFM), percent fat mass (PFM), and percent total weight loss (%TWL), were eligible. For each outcome, the mean and standard deviation (for changes from baseline) were used to synthesize the data. RESULTS: Eight trials were included in the current study. The results of the meta-analysis indicated protein intake higher than the recommended value after bariatric surgery led to more weight loss by 4.95 kg (95 % CI: -9.41 to -0.49) and FM loss by 7.64 kg (95 % CI: -14.01 to -1.28) compared with the control group. However, it had no significant effects on postoperative changes in BMI, FFM, PFM, or %TWL. There were no significant differences in body composition between protein sources obtained from diet and supplementation. When data was stratified based on the amount of added protein, we found a significant reduction in weight (MD: -7.80 kg; 95 % CI: -14.50 to -1.10) in patients who consumed protein ≥ 40 g/d in addition to the recommended value. Besides, protein intake higher than the recommended value declined FFM loss in patients who underwent laparoscopic sleeve gastrectomy (LSG) (MD: 6.52 kg; 95 % CI: 0.99 to 12.02). CONCLUSION: The results of the current meta-analysis indicated that protein intake higher than the recommended value might cause greater weight and FM loss after bariatric surgery than a normal protein diet. However, our findings did not support the role of additional protein in the preservation of FFM, except in patients with LSG.

High-fat and carbohydrate diet caused chronic kidney damage by disrupting kidney function, caspase-3, oxidative stress and inflammation.

The study aimed to compare the effects of a diet rich in fat, carbohydrates and protein on rat kidneys. The study was conducted on 40 Wistar albino rats bred at Inönü University Faculty of Medicine after the approval of the ethics committee. Rats were randomly divided into 4 groups: Control group, and the groups where the animals were fed with high carbohydrate, fat and protein rich feed. After the applications, the rat kidney tissues were removed by laparoscopy under anesthesia and blood samples were collected. 13 weeks long fat-rich and carbohydrate feed application had negative effects on oxidant-antioxidant balance, oxidative stress index, inflammation markers, kidney functions tests, histopathology and immunohistochemistry caspase-3 findings in rat kidney tissues, especially in the carbohydrate group when compared to the controls. Protein-rich feed, there were no significant difference in biochemical and histopathology compared to the control group. Fat and carbohydrate rich feed led to an increase in oxidative stress in rat kidney tissues. Oxidative stress led to nephrotoxicity, which in turn led to chronic kidney tissue damages. A more balanced and protein-rich diet instead of excessive sugar and fatty food intake could be suggested to prevent chronic kidney damage.

Growth performance, serum parameters, inflammatory responses, intestinal morphology and microbiota of weaned piglets fed 18% crude protein diets with different ratios of standardized ileal digestible isoleucine to lysine.

The present study was to explore the Ile requirement of piglets fed 18% crude protein (CP) diets. Two hundred and fifty 28-day-old Duroc × Landrace × Yorkshire piglets (8.37 ± 1.92 kg) were randomly divided into 5 dietary treatments (10 piglets per replicate, 5 barrows and 5 gilts per replicate) with 45%, 50%, 55%, 60%, 65% standardized ileal digestible (SID) Ile-to-Lys ratios, and the SID Lys was formulated to 1.19%. The experimental design consisted of two phases (d 1 to 14 and d 15 to 28). Results showed that average daily gain (ADG) had a tendency to quadratically increase as the SID Ile-to-Lys ratio increased (P = 0.09), and the optimum SID Ile-to-Lys ratios required to maximize ADG were 48.33% and 54.63% for broken-line linear model and quadratic polynomial model, respectively. Different SID Ile-to-Lys ratios had no significant effects on average daily feed intake and gain-to-feed ratio. Dry matter (P < 0.01), CP (P = 0.01), ether extract (P = 0.04), gross energy (P < 0.01) and organic matter (P < 0.01) digestibility increased quadratically. Serum total cholesterol levels decreased linearly (P = 0.01) and quadratically (P < 0.01); aspartate aminotransferase (P < 0.01), interleukin-1ß (P = 0.01), and tumor necrosis factor-α (P < 0.01) levels decreased quadratically; immunoglobulin G (P = 0.03) and immunoglobulin M (P = 0.01) concentrations increased quadratically. Serum Ser levels decreased linearly (P < 0.01) and quadratically (P = 0.01); Glu (P = 0.02), Arg (P = 0.05), and Thr (P = 0.03) levels decreased quadratically; Gly (P < 0.01) and Leu (P = 0.01) levels decreased linearly; Ile (P < 0.01) concentration increased linearly. Duodenal villus height (P < 0.01) and villus height to crypt depth ratio (P < 0.01) increased quadratically. The deficiency or excess of Ile decreased short chain fatty acid-producing bacteria abundance and increased pathogenic bacteria abundance. Overall, taking ADG as the effect index, the optimum SID Ile-to-Lys ratios of piglets offered 18% CP diets were 48.33% and 54.63% based on two different statistical models, respectively, and the deficiency or excess of lle negatively affected piglet growth rates and health status.

Effect of supplementing an α-amylase enzyme or a blend of essential oil components on the performance, nutrient digestibility and nitrogen balance of dairy cows.

Lowering the dietary protein content is a promising strategy to reduce N excretions in cattle but requires an improved N utilization by the animal. Feed enzymes (e.g., exogenous α-amylase) and plant extracts (e.g., essential oils (EO)) are 2 additives which may enhance rumen function and possibly also microbial protein yield. This may increase fat and protein corrected milk yield (MY) and milk nitrogen efficiency (MNE) and thus lower N losses from dairy cows. Both types of additives were studied in an experiment including 39 Holstein cows (average ± SD: 40.7 ± 7.95 kg/d MY, 89 ± 43 d in milk (DIM), 2.7 ± 1.5 lactations, 677 ± 68.6 kg of BW) consisting of a covariate (4 weeks) and treatment period (5 weeks). During the whole experiment cows were fed a typical Benelux diet (CTRL), supplemented with concentrates to meet individual requirements for energy and metabolizable protein, which were fulfilled for 100% and 101%, respectively. The total diet was low in crude protein (15.5%) and relatively high in starch (22.6% and 6.6% rumen bypass starch). Cows were balanced for parity, DIM, MY and roughage intake and randomly assigned to one of 3 groups, receiving the following treatments in the treatment period; (1) CTRL (n = 13); (2) CTRL + 14 g/cow/d Ronozyme RumiStar (α-amylase enzyme, DSM) (AMEZ, n = 13); (3) CTRL + 2.5 g/cow/d Crina Protect (blend of EO components, DSM) (ESOL, n = 13). Animal performance, ruminal pH and enteric gas emissions were monitored throughout the experiment. During the last week of the covariate and treatment period, nitrogen balances were conducted, total-tract nutrient digestibility was determined and urinary allantoin and uric acid were determined as indicators for microbial N production. The statistical model applied to these variables contained group and DIM during treatment period as fixed effects and the values from the covariate period as covariate. Post-hoc Dunnet corrected comparisons between each treatment group and the control group were explored. The α-amylase enzyme tended to increase apparent total-tract starch digestibility and increased milk lactose concentration. The EO blend tended to increase milk yield and increased milk N output, MNE and feed efficiency. Therefore, when feeding reduced dietary protein levels, EO have potential to improve the N-use efficiency in cattle, whereas the α-amylase enzyme might increase starch digestibility and milk lactose. However, additional research is necessary to substantiate our findings.

The association between bone density of lumbar spines and different daily protein intake in different renal function.

BACKGROUND: Low protein intake (LPI) has been suggested as a treatment for chronic kidney disease (CKD). However, protein intake is essential for bone health. METHODS: We studied the database of the National Health and Nutrition Examination Survey, 2005-2010. Basic variables, metabolic diseases, and bone density of different femoral areas were stratified into four subgroups according to different protein intake (DPI) (that is, <0.8, 0.8-1.0, 1.0-1.2, and >1.2 g/kg/day). RESULTS: Significant differences were found among all lumbar area bone mineral density (BMD) and T-scores (p < 0.0001). There was an apparent trend between a decreasing BMD in the CKD groups with increasing DPI in all single lumbar spines (L1, L2, L3, and L4) and all L spines (L1-L4). Compared with DPI (0.8-1.0 g/day/kg), higher risks of osteoporosis were noticed in the subgroup of >1.2 g/day/kg over L2 (relative risk (RR)=1.326, 95% confidence interval (CI)=1.062-1.656), subgroup >1.2 g/day/kg over L3 (RR = 1.31, 95%CI = 1.057-1.622), subgroup <0.8 g/day/kg over L4 (RR = 1.276, 95%CI = 1.015-1.605), subgroup <0.8 g/day/kg over all L spines (RR = 11.275, 95%CI = 1.051-1.548), and subgroup >1.2 g/day/kg over all L spines (RR = 0.333, 95%CI = 1.098-1.618). However, a higher risk of osteoporosis was observed only in the non-CKD group. There was an apparent trend of higher DPI coexisting with lower BMD and T scores in patients with CKD. For osteoporosis (reference:0.8-1.0 g/day/kg), lower (<0.8 g/day/kg) or higher DPI (>1.2 g/day/kg) was associated with higher risks in the non-CKD group, but not in the CKD group. CONCLUSIONS: In the CKD group, LPI for renal protection was safe without threatening L spine bone density and without causing a higher risk of osteoporosis.

A low-protein diet should be encouraged in patients with CKD, but protein is essential for bone health. In this study, we showed that a low-protein diet did not affect lumbar bone density. Therefore, in the care of CKD, a low-protein diet is beneficial for renal function and without harm to lumbar bone health.

Epidermal tyrosine catabolism is crucial for metabolic homeostasis and survival against high-protein diets in Drosophila.

The insect epidermis forms the exoskeleton and determines the body size of an organism. How the epidermis acts as a metabolic regulator to adapt to changes in dietary protein availability remains elusive. Here, we show that the Drosophila epidermis regulates tyrosine (Tyr) catabolism in response to dietary protein levels, thereby promoting metabolic homeostasis. The gene expression profile of the Drosophila larval body wall reveals that enzymes involved in the Tyr degradation pathway, including 4-hydroxyphenylpyruvate dioxygenase (Hpd), are upregulated by increased protein intake. Hpd is specifically expressed in the epidermis and is dynamically regulated by the internal Tyr levels. Whereas basal Hpd expression is maintained by insulin/IGF-1 signalling, Hpd induction on high-protein diet requires activation of the AMP-activated protein kinase (AMPK)-forkhead box O subfamily (FoxO) axis. Impairment of the FoxO-mediated Hpd induction in the epidermis leads to aberrant increases in internal Tyr and its metabolites, disrupting larval development on high-protein diets. Taken together, our findings uncover a crucial role of the epidermis as a metabolic regulator in coping with an unfavourable dietary environment.