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The Journal of Nutrition Feb 1988Factors influencing microbial protein synthesis in the rumen have been reviewed several times in recent years. Original publications in the past 3 yr have reported... (Review)
Review
Factors influencing microbial protein synthesis in the rumen have been reviewed several times in recent years. Original publications in the past 3 yr have reported microbial and feed protein nitrogen contribution postruminally when feeding a variety of dietary proteins. Ammonia is a satisfactory source of nitrogen for growth of the majority of rumen species, but substitution of intact protein for urea (source of ammonia) usually stimulates microbial protein production. Protein sources such as soybean meal appear to possess properties (perhaps rate of degradability) that optimize microbial growth in vivo. Protein sources more undegradable than soybean meal, when fed as the major nitrogen source, sometimes reduce microbial growth. However, nondegradable proteins may compensate for less microbial protein by supplying intact dietary protein postruminally, so the amino acids potentially available may be equal to or greater than those available when readily degradable protein is fed. Soybean meal may reduce microbial growth in diets containing grass silage at protein exceeding 16.8%. Various measurements of microbial and intact dietary protein postruminally show that the contribution of each can be manipulated. Accuracy of quantitative predictions of postruminal contribution depends on several factors that require more research.
Topics: Animals; Bacterial Proteins; Dietary Proteins; Nitrogen; Rumen
PubMed: 3276848
DOI: 10.1093/jn/118.2.242 -
Association between Dietary Protein Intake and Cognitive Function in Adults Aged 60 Years and Older.The Journal of Nutrition, Health & Aging 2020The aim of this study was to examine the association of dietary protein intake and protein sources with cognitive function in population aged 60 years and older.
OBJECTIVES
The aim of this study was to examine the association of dietary protein intake and protein sources with cognitive function in population aged 60 years and older.
DESIGN
Cross-sectional study.
SETTING
The National Health and Nutrition Examination Survey (NHANES) 2011-2014.
PARTICIPANTS
Non-institutionalized US adults aged 60 years and older.
MEASUREMENTS
Cognitive functions were assessed by a series of cognitive tests. Dietary protein intake was assessed by two 24-hour dietary recall interviews. Linear regression analyses were used to assess the associations between quartiles of dietary protein intake and cognitive function.
RESULTS
Protein intake was positively associated with cognitive function. In full-adjusted model, the significant association between dietary protein intake and Recall Test score was observed (quartile (Q) 2 versus Q1, β=0.24, 95%CI: 0.01 to 0.47); the association between protein intake and Animal Fluency test was significant (Q2 versus Q1, β=1.40, 95%CI: 0.51 to 2.29; Q4 versus Q1, β=1.42, 95%CI: 0.37 to 2.48); the positive associations with DSST score and Composite z-score were observed both in Q2 versus Q1 and Q3 versus Q1 of protein intake. Protein intake from total animal, total meat, eggs and legumes were associated with a better performance on certain cognitive tests. However, an adverse association between higher protein intake from milk and milk products and cognitive function was observed.
CONCLUSIONS
We found the positive associations of dietary protein intake and protein intake from total animal, total meat, eggs and legumes with cognitive function in adults aged 60 years and older, while higher milk and milk products were negatively associated with cognitive function.
Topics: Animals; Cognition; Cross-Sectional Studies; Diet; Dietary Proteins; Female; Humans; Male; Middle Aged; Nutritional Status
PubMed: 32003415
DOI: 10.1007/s12603-020-1317-4 -
World Review of Nutrition and Dietetics 1983
Review
Topics: Amino Acids; Animals; Arteriosclerosis; Birds; Cattle; Cholesterol; Diet, Atherogenic; Dietary Proteins; Dogs; Haplorhini; Humans; Rabbits; Rats; Swine
PubMed: 6428068
DOI: 10.1159/000408349 -
JAMA Apr 2012
Topics: Body Composition; Dietary Proteins; Energy Metabolism; Female; Humans; Hyperphagia; Male; Weight Gain
PubMed: 22535849
DOI: 10.1001/jama.2012.532 -
Nestle Nutrition Institute Workshop... 2011Intact protein, protein hydrolysates, and free amino acids are popular ingredients in contemporary sports nutrition, and have been suggested to augment post-exercise...
Intact protein, protein hydrolysates, and free amino acids are popular ingredients in contemporary sports nutrition, and have been suggested to augment post-exercise recovery. Protein and/or amino acid ingestion stimulates skeletal muscle protein synthesis, inhibits protein breakdown and, as such, stimulates muscle protein accretion following resistance and endurance type exercise. This has been suggested to lead to a greater adaptive response to each successive exercise bout, resulting in more effective muscle reconditioning. Despite limited evidence, some basic guidelines can be defined regarding the preferred type, amount, and timing of dietary protein that should be ingested to maximize post-exercise muscle protein accretion. Whey protein seems most effective in stimulating muscle protein synthesis during acute post-exercise recovery. This is likely attributable to its rapid digestion and absorption kinetics and specific amino acid composition. Ingestion of approximately 20 g protein during and/or immediately after exercise is sufficient to maximize post-exercise muscle protein synthesis rates. Coingestion of a large amount of carbohydrate or free leucine is not warranted to further augment post- exercise muscle protein synthesis when ample protein is already ingested. Future research should focus on the relevance of the acute anabolic response following exercise to optimize the skeletal muscle adaptive response to exercise training.
Topics: Caseins; Dietary Carbohydrates; Dietary Proteins; Exercise; Glycogen; Humans; Hypertrophy; Leucine; Milk Proteins; Muscle Proteins; Muscle, Skeletal; Musculoskeletal Physiological Phenomena; Physical Endurance; Protein Hydrolysates; Whey Proteins
PubMed: 22301837
DOI: 10.1159/000329287 -
Nutrients Oct 2022Sarcopenia is a multifactorial disease that limits autonomy for the growing elderly population. An optimal amount of dietary protein has shown to be important to... (Comparative Study)
Comparative Study Randomized Controlled Trial
Comparing Even with Skewed Dietary Protein Distribution Shows No Difference in Muscle Protein Synthesis or Amino Acid Utilization in Healthy Older Individuals: A Randomized Controlled Trial.
Sarcopenia is a multifactorial disease that limits autonomy for the growing elderly population. An optimal amount of dietary protein has shown to be important to maintain muscle mass during aging. Yet, the optimal distribution of that dietary protein has not been fully clarified. The aim of the present study was to examine whether an even, compared to a skewed, distribution of daily dietary protein leads to higher muscle protein synthesis and amino acid utilization. Twelve healthy males and twelve healthy females aged between 65 and 80 years were block randomized to either an even (EVEN, = 12) or skewed (SKEWED, = 12) dietary protein distribution for three daily main meals. Seven days of habituation were followed by three trial days, which were initiated by oral intake of deuterium oxide (DO). The dietary protein throughout all trial meals was intrinsically labelled with H-phenylalanine. Blood samples were drawn daily, and muscle biopsies were taken before and at the end of the trial to measure muscle protein synthesis (FSR) and muscle protein incorporation of the dietary-protein-derived tracer. Muscle protein FSR was no different between the two groups (EVEN 2.16 ± 0.13%/day and SKEWED 2.23 ± 0.09%/day, = 0.647), and the muscle protein incorporation of the intrinsically labeled H-phenylalanine tracer was not different between the two groups (EVEN 0.0049 ± 0.0004 MPE% and SKEWED 0.0054 ± 0.0003 MPE%, = 0.306). In conclusion, the daily distribution pattern of the dietary protein did not affect muscle protein synthesis or the utilization of dietary protein.
Topics: Aged; Aged, 80 and over; Female; Humans; Male; Amino Acids; Dietary Proteins; Muscle Proteins; Muscle, Skeletal; Phenylalanine
PubMed: 36364705
DOI: 10.3390/nu14214442 -
The Journal of Nutrition Jun 1998The average American diet, which is high in protein and low in fruits and vegetables, generates a large amount of acid, mainly as sulfates and phosphates. The kidneys... (Review)
Review
The average American diet, which is high in protein and low in fruits and vegetables, generates a large amount of acid, mainly as sulfates and phosphates. The kidneys respond to this dietary acid challenge with net acid excretion, as well as ammonium and titratable acid excretion. Concurrently, the skeleton supplies buffer by active resorption of bone. Indeed, calciuria is directly related to net acid excretion. Different food proteins differ greatly in their potential acid load, and therefore in their acidogenic effect. A diet high in acid-ash proteins causes excessive calcium loss because of its acidogenic content. The addition of exogenous buffers, as chemical salts or as fruits and vegetables, to a high protein diet results in a less acid urine, a reduction in net acid excretion, reduced ammonium and titratable acid excretion, and decreased calciuria. Bone resorption may be halted, and bone accretion may actually occur. Alkali buffers, whether chemical salts or dietary fruits and vegetables high in potassium, reverse acid-induced obligatory urinary calcium loss. We conclude that excessive dietary protein from foods with high potential renal acid load adversely affects bone, unless buffered by the consumption of alkali-rich foods or supplements.
Topics: Acids; Aging; Bone and Bones; Calcium; Dietary Proteins; Dose-Response Relationship, Drug; Humans
PubMed: 9614169
DOI: 10.1093/jn/128.6.1051 -
Journal of Dairy Science Dec 2020Our objectives were to determine (1) the sources of variation in cow responses to dietary protein reduction, and (2) the association of low dietary protein resilience...
Our objectives were to determine (1) the sources of variation in cow responses to dietary protein reduction, and (2) the association of low dietary protein resilience (LPR) with protein efficiency. Lactating Holstein cows in peak lactation (n = 166; 92 primiparous, 77 multiparous) with initial milk yield 41 ± 9.8 kg/d were fed high-protein (HP) or low-protein (LP) diets in 4-wk periods in a crossover design with half the cows fed LP first and half fed HP first. The study was repeated for 69 of these cows (42 primiparous, 27 multiparous) in late lactation. Low-protein diets were 14% crude protein (CP) in peak lactation and 13% CP in late lactation and were formulated to contain adequate rumen-degradable protein to maintain rumen function but inadequate rumen-undegradable protein for cows with average production in this study to maintain their production. High-protein diets were 18% CP in peak lactation and 16% CP in late lactation and contained extra expeller soybean meal to meet metabolizable protein requirements. Protein efficiency was defined as the protein captured in milk or in both milk and body tissues per unit of consumed protein. Low dietary protein resilience was calculated for each cow in peak and late lactation based on actual intake, production, and body weight measures. The ability of a cow to maintain total protein captured in milk and body gain when fed less protein varied considerably and the variation was mostly explained by a cow's captured protein per kilogram of metabolic body weight when fed HP, her parity, treatment sequence, and experiment. Protein efficiency was moderately repeatable across diets within lactation stage. Milk urea nitrogen was not associated with protein efficiency in individual cows within a diet and lactation stage. Cows with greater dietary protein resiliency (higher LPR) had similar protein efficiency on the HP diet as cows with lower LPR, but higher protein efficiency on the LP diet. In conclusion, cows generally maintained their protein efficiency rankings when switching diets between sufficient or insufficient protein; however, some high-producing cows are better able to maintain high production when fed less protein. We define this ability as LPR and suggest it might be useful for identifying cows that use protein more efficiently to enhance dairy sustainability.
Topics: Animal Feed; Animals; Body Weight; Cattle; Cross-Over Studies; Dairying; Diet; Diet, Protein-Restricted; Dietary Proteins; Female; Lactation; Milk; Milk Proteins; Parity; Pregnancy; Rumen; Glycine max
PubMed: 33222854
DOI: 10.3168/jds.2020-18143 -
Biological Trace Element Research Jul 2022The present study investigates the effect of different dietary protein levels suboptimum level (25%) and optimum level (35%), different Zn forms bulk zinc oxide (BZnO)...
Synergistic Effects Between Dietary Zinc Form Supplementation and Dietary Protein Levels on Performance, Intestinal Functional Topography, Hemato-biochemical Indices, Immune, Oxidative Response, and Associated Gene Expression of Nile Tilapia Oreochromis niloticus.
The present study investigates the effect of different dietary protein levels suboptimum level (25%) and optimum level (35%), different Zn forms bulk zinc oxide (BZnO) or nanoparticles zinc oxide (NZnO), and their interaction on performance, intestinal topography, hematology, serum biochemical, antioxidant-immune responses, and related gene expression of Nile tilapia. Six experimental diets were formulated to contain approximately 25% and 35% crude protein and supplemented with Zn forms with 0 (normal level in ingredients), 60 mg kg BZnO and 60 mg kg nanoparticles of NZnO. Nile tilapia, Oreochromis niloticus, fingerlings (7.53 ± 0. 06 g) were fed on one of tested diets in triplicates with 5% of total biomass three times a day for 84 days. Results showed that, fish fed diet containing 35% crude protein and supplemented with NZnO form recorded the highest final body weight (FBW), weight gain (WG), and specific growth rate (SGR). However, no significant (P > 0.05) differences were recorded in FBW, WG, SGR, feed conversion ratio (FCR), and protein efficiency ratio (PER) between fish fed diet containing 35% crude protein without Zn supplementation and fish fed diet containing 25% crude protein supplemented with NZnO form. Either fish fed diet containing 25% or 35% crude protein and supplemented with NZnO exhibited the highest values of villi height/width. The highest absorption surface area (ASA) was obtained in fish fed diet containing 25% or 35% crude protein and supplemented with BZnO. Hemoglobin (Hb), hematocrit (Hct), and red blood cell count (RBCs) highest values were obtained for fish fed diet containing protein level 35% supplemented with NZnO. Fish fed diet containing protein level 35% and supplemented with NZnO had the lowest value of alanine amino transferase (ALT) and aspartate amino transferase (AST). The highest globulin value was recorded for fish provided with diet containing 35% crude protein and supplemented with BZnO followed by those fed diet containing 35% crude protein and supplemented with NZnO. Fish fed diet containing protein level 25% with NZnO supplementation recorded the highest super oxide dismutase (SOD), catalase (CAT), glutathione reductase (GSH), and glutathione peroxidase (GP, with decreasing malondialdehyde (MAD) values. The highest values of immunoglobulin g (IgG), immunoglobulin M (IgM), complement 4 (C4), and complement 3 (C3) were obtained for diet containing 35% crude protein and supplemented with NZnO form. Growth hormone gene (GH) was upregulated in fish fed 25% dietary protein without Zn supplementation, while it was downregulated in fish fed 25% dietary protein and supplemented with NZnO. Transcription of insulin-like growth factor-1 (IGF-I) gene recorded the highest value for fish fed 35% crude protein and supplemented with BZnO. This is although the diet of 35% crude protein + NZnO induced significant (IGF-I) gene expression compared with 25% crude protein with or without BZnO. Therefore, nano zinc is useful as a feed supplement for Nile tilapia (Oreochromis niloticus).
Topics: Animal Feed; Animals; Cichlids; Diet; Dietary Proteins; Dietary Supplements; Gene Expression; Insulin-Like Growth Factor I; Oxidative Stress; Zinc; Zinc Oxide
PubMed: 34487300
DOI: 10.1007/s12011-021-02911-y -
Journal of the American College of... Dec 2004Body composition changes as people get older. One of the noteworthy alterations is the reduction in total body protein. A decrease in skeletal muscle is the most... (Review)
Review
Body composition changes as people get older. One of the noteworthy alterations is the reduction in total body protein. A decrease in skeletal muscle is the most noticeable manifestation of this change but there is also a reduction in other physiologic proteins such as organ tissue, blood components, and immune bodies as well as declines in total body potassium and water. This contributes to impaired wound healing, loss of skin elasticity, and an inability to fight infection. The recommended dietary allowance (RDA) for adults for protein is 0.8 grams of protein per kilogram of body weight. Protein tissue accounts for 30% of whole-body protein turnover but that rate declines to 20% or less by age 70. The result of this phenomenon is that older adults require more protein/kilogram body weight than do younger adults. Recently, it has become clear that the requirement for exogenous protein is at least 1.0 gram/kilogram body weight. Adequate dietary intake of protein may be more difficult for older adults to obtain. Dietary animal protein is the primary source of high biological value protein, iron, vitamin B(12), folic acid, biotin and other essential nutrients. In fact, egg protein is the standard against which all other proteins are compared. Compared to other high-quality protein sources like meat, poultry and seafood, eggs are the least expensive. The importance of dietary protein cannot be underestimated in the diets of older adults; inadequate protein intake contributes to a decrease in reserve capacity, increased skin fragility, decreased immune function, poorer healing, and longer recuperation from illness.
Topics: Aged; Aging; Body Composition; Dietary Proteins; Energy Metabolism; Humans; Motor Activity; Muscle, Skeletal; Nutritional Requirements
PubMed: 15640517
DOI: 10.1080/07315724.2004.10719434