Utilization Of Dietary Protein Research Articles

Effects of protein or amino-acid supplementation on the physical growth of young children in low-income countries.

Child growth stunting is common in low-income countries, possibly due to insufficient protein intakes. Most previous studies have concluded that children’s protein intakes are adequate in relation to estimated requirements, but these studies did not consider issues of protein digestibility and effects of infection on dietary protein utilization. Using an alternative approach to assess the possible role of protein inadequacy in children’s growth restriction, the results of 18 intervention trials in which supplementary protein or amino acids were provided to children ages 6–35 months and growth outcomes were reviewed. Eight studies conducted in hospitalized children recovering from acute malnutrition found that the recommended protein intake levels for healthy children supported normal growth rates, but higher intakes were needed for accelerated rates of “catch-up” growth. Ten community-based studies did not demonstrate a consistent benefit of supplemental protein on children’s growth. However, weaknesses in the study designs limit the conclusions that can be drawn from these studies, and additional appropriately designed trials are needed to answer this question definitively. Recommendations for optimizing future study designs are provided herein.

Dietary protein complexity modulates growth, protein utilisation and the expression of protein digestion-related genes in Senegalese sole larvae

Given its complex metamorphosis and digestive system ontogeny, Senegalese sole larvae capacity to digest and utilize dietary protein is likely to change throughout development. In the present study, we hypothesized that the manipulation of dietary protein complexity may affect Senegalese sole larvae capacity to digest, absorb and retain protein during metamorphosis, as well as the mRNA expression of genes encoding for the precursors of proteolytic enzymes of the digestive tract and the enterocyte peptide transporter PepT1, which may have further impact on somatic growth. Three diets were formulated using approximately the same practical ingredients, except for the main protein source. The Intact diet protein content was mostly based on intact plant protein where the target peptide molecular weight (MW) would be >70kDa. The PartH diet protein fraction was mostly based on a protein hydrolysate with a high content of 5–70kDa peptides. The HighH diet protein fraction was mostly based on a protein hydrolysate with a high content of 5kDa peptides. A growth trial was performed with larvae reared at 19°C under a co-feeding regime from mouth opening. The transcription of pga, tryp1c, ialp, ampn and pepT1 (encoding respectively for PepsinogenA, Trypsinogen1C, Intestinal alkaline phosphatase, Aminopeptidase N and for the enterocyte peptide transporter 1) was quantified by qPCR, during the metamorphosis climax (16DAH) and after the metamorphosis was completed (28DAH). An in vivo method of controlled tube-feeding was used to assess the effect on the larvae capacity to utilize polypeptides with different MW (1.0 and 7.2kDa) representing a typical peptide MW of each of the hydrolysates included in the diets. The PartH diet stimulated growth in metamorphosing larvae (16DAH), whereas the Intact diet stimulated growth after 36DAH. The Intact diet stimulated the larvae absorption capacity for 1.0kDa peptides at 16DAH, which may have contributed for enhanced growth in later stages. The PartH diet stimulated the transcription of tryp1c and pept1 at 28DAH, which seemed to reflect on increased post-larvae capacity to retain dietary 7.2kDa polypeptides. That may indicate a possible strategy to optimize the digestion and utilisation of the PartH dietary protein, though it did not reflect into increased growth. The Intact diet promoted the transcription of pepsinogenA, which may reflect a reduced gastrointestinal transit time, which could have enhanced the dietary nutrients assimilation, ultimately improving growth. The present results suggest that, whereas pre-metamorphic sole larvae utilize better dietary protein with a moderate degree of hydrolysis, post-metamorphic sole make a greater use of intact protein.

Influence of Dietary Protein Source and Utilisation of Copra Meal in Finishing Broiler Chicken

The effect of dietary protein sources on the utilisation of copra meal was investigated in Cobb broilers. A control finisher diet based on fish meal (FM), meat and bone meal (MBM) and full-fat soybean (FFSB) and four other diets containing expeller copra meal (ECM) with combinations of these traditional protein sources (FM+ MBM, FFSB+FM, FFSB+FM+MBM and FFSB+MBM) were fed each to 4 replicates of 5 birds each in a completely randomized design. Body weight gain was highest (P<0.05) in birds fed diets containing ECM with FM+MBM. There were no significant dietary effects on feed intake and feed conversion ratio. Dressing percentage was depressed (P<0.05) in the diet based on ECM with FFSB+FM+MBM. The relative weight of breast muscle reduced (P<0.05) in group offered ECM along with FFSB+FM and FFSB+FM+MBM. Furthermore, there were no dietary effects on the weight of thighs and drumsticks. Nevertheless, birds fed ECM with FM+MBM recorded the lowest (P<0.05) weights of digesta in the crop and small intestine. There were no significant dietary effects on weight of digesta in the gizzard and caeca. The highest (P<0.05) digesta weight in the proventriculus was observed in the birds fed on FFSB+FM+MBM. Total tract apparent digestibility of DM and CP improved (P<0.05) on FM+MBM. Total tract nitrogen retention was lower (P<0.05) with FFSB+FM and FFSB+MBM as compared to control. However, fat digestibility was depressed (P<0.05) in the control diet. It could be concluded that dietary protein sources exerted significant influence on the utilisation of copra meal by broilers and the combination of ECM with animal protein sources yielded the best results in terms of performance of Cobb broilers.

Effect of increasing dietary metabolizable protein on nitrogen efficiency in Holstein dairy cows.

ObjectiveThe objective of the study was to determine the effects of increasing levels of metabolizable protein (MP) on lactation performance and nitrogen (N) efficiencies in lactating dairy cows.MethodsNine multiparous cows in mid lactation [113±25 days in milk] received three treatments in a 3×3 Latin square design with a period length of 21 days. The treatments were three diets, designed to provide similar energy and increasing supply of MP (g/d) (2,371 [low], 2,561 [medium], and 2,711 [high] with corresponding crude protein levels [%]) 15.2, 18.4, and 20.9, respectively.ResultsIncreasing MP supplies did not modify dry matter intake, however, it increased milk protein, fat, and lactose yield linearly. Similarly, fat corrected milk increased linearly (9.3%) due to an increase in both milk yield (5.2%) and milk fat content (7.8%). No effects were observed on milk protein and lactose contents across the treatments. Milk nitrogen efficiency (MNE) decreased from 0.26 to 0.20; whereas, the metabolic efficiency of MP decreased from 0.70 to 0.60 in low to high MP supplies, respectively. The concentration of blood urea nitrogen (BUN) increased linearly in response to increasing MP supplies.ConclusionIncreasing MP supplies resulted in increased milk protein yield; however, a higher BUN and low MNE indicated an efficient utilization of dietary protein at low MP supplies.

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.

Supplementing taurine to plant-based diets improves lipid digestive capacity and amino acid retention of Senegalese sole (Solea senegalensis) juveniles

Recent studies reported positive effects of taurine supplementation to plant protein-based diets on fish growth performance and feed conversion ratio but the mechanisms involved remain unclear. The objective of this work was to provide a first insight on the importance of taurine on dietary protein and lipid absorption and utilisation, in Senegalese sole (Solea senegalensis) juveniles fed plant-based diets. Seven practical diets were tested: a fishmeal-based diet (FM) and a plant protein-based formula (PP85) to which taurine was added in graded levels: 0.2% (TAU1), 0.3% (TAU2), 0.4% (TAU3), 0.7% (TAU4) and 1.5% (TAU5). Short-term metabolic trials were performed by tube-feeding the different experimental diets labelled with different tracers: 14C-taurine, 14C-triolein (as tracer of dietary triacylglycerol) and a mixture of 14C-amino acids. Feeding sole juveniles with the PP85 diet affected taurine metabolism, since a higher proportion of dietary taurine was directed to gallbladder and probably used for bile salt synthesis. Consistent with this, fish receiving the plant-based low taurine-content diets (PP85 and TAU1) displayed a poor triacyglycerol digestion capacity. A higher proportion of 14C-amino acids was retained in fish muscle when fed the TAU5 compared to the PP85 diet. These short-term trials suggested that taurine supplementation to a plant-based diet might be beneficial to sole performance by enhancing bile salt synthesis and triacylglycerol digestion as well as muscle amino acid retention. However, this dietary supplementation should be tested in long-term trials to verify the effect on fish growth and to assess the beneficial effects on protein and lipid metabolism suggested here. Statement of relevance in the general field of aquaculture (limited to 60 characters)Adding taurine to a plant-based diet is beneficial for sole

Expression pattern of peptide and amino acid genes in digestive tract of transporter juvenile turbot (Scophthalmus maximus L.)

Turbot (Scophthalmus maximus L.), a carnivorous fish species with high dietary protein requirement, was chosen to examine the expression pattern of peptide and amino acid transporter genes along its digestive tract which was divided into six segments including stomach, pyloric caeca, rectum, and three equal parts of the remainder of the intestine. The results showed that the expression of two peptide and eleven amino acid transporters genes exhibited distinct patterns. Peptide transporter 1 (PepT1) was rich in proximal intestine while peptide transporter 2 (PepT2) was abundant in distal intestine. A number of neutral and cationic amino acid transporters expressed richly in whole intestine including B0-type amino acid transporter 1 (B0AT1), L-type amino acid transporter 2 (LAT2), T-type amino acid transporter 1 (TAT1), proton-coupled amino acid transporter 1 (PAT1), y+L-type amino acid transporter 1 (y+LAT1), and cationic amino acid transporter 2 (CAT2) while ASC amino acid transporter 2 (ASCT2), sodium-coupled neutral amino acid transporter 2 (SNAT2), and y+L-type amino acid transporter 2 (y+LAT2) abundantly expressed in stomach. In addition, system b0,+ transporters (rBAT and b0,+AT) existed richly in distal intestine. These findings comprehensively characterized the distribution of solute carrier family proteins, which revealed the relative importance of peptide and amino acid absorption through luminal membrane. Our findings are helpful to understand the mechanism of the utilization of dietary protein in fish with a short digestive tract.

Factors Influencing the Amino Acid and Peptide Transporter Proteins mRNA Expression in Avian Species.

The commercial strains of broiler chickens have genetically selected to reach market weight at younger ages. In order to sustain increased growth rate requires an efficient assimilation of nutrients from the intestinal lumen, which is permitted through nutrient assimilation through the enterocytes that is facilitated by many nutrient transporter proteins. These trans-membrane proteins have specific action, well known kinetics and assist in the partitioning of nutrients among tissues. Amino acids are transported across the plasma membrane as free amino acids or short chain peptides through several independent systems encoded by various nutrient transporter gene products, and these systems may act on multiple substrates. Any deficiency in amino acid and peptide transportation results in metabolic disorders, illustrating crucial roles being played by the body's ability to maintain amino acid homeostasis. The ability of tissues to adapt to changes in input of amino acids related to numerous external factors that negatively affect amino acids utilization appears to result from responses that alter nutrient transporter protein mRNA expression mandated for to maintain amino acid and protein homeostasis. This review summarizes the results of some recently published scientific articles on the effects of different factors that influence intestinal amino acid and peptide transporter proteins mRNA expressions in domestic fowl. Understanding the regulatory effects of diet on amino acid and peptide transport systems in tissues offers insight that ostensibly will help nutritionists to improve the efficiency of dietary protein utilization in poultry.

Ammonia nitrogen excretion in Mandarin Fish (Siniperca chuatsi) and Grass Carp (Ctenopharyngodon idellus) fed practical diets: the effects of water temperature

To understand the actual production of fish culture about the utilization of dietary protein and excreta impact on the environment between mandarin fish (Siniperca chuatsi) and grass carp (Ctenopharyngodon idellus), the study to investigate the effect of temperatures (19 ± 0.5°C, 24 ± 0.5°C and 29 ± 0.5°C) on ammonia-N excretion in mandarin fish and grass carp under fed and fasted states was conducted. These two species were fed a practical diet containing 325.2 g kg−1 crude protein at 3% body weight per day. The ammonia-N excretion rate was significantly increased when temperature increased from 19 to 29°C, and a linear relationship between ammonia-N excretion rate and temperature. The maximum ammonia-N excretion levels of mandarin fish and grass carp were observed at 4–8 h and 2–4 h after feeding, respectively, and the minimum values for both species were observed at 24 h after feeding. Under the feeding condition, mandarin fish had a lower ammonia-N excretion level compared to grass carp at 24°C and 29°C. The average amount of ammonia-N excreted by mandarin fish at 24 h is significantly higher than grass carp under fasting conditions, except 19 ± 0.5°C. These results indicated that mandarin fish might make better use of protein at higher temperature than grass carp when fed practical diets in commercial production. These results of this study suggested that mandarin fish had a lower ammonia-N excretion level compared with grass carp, making a less contribution to environmental loading in an intensive fish culture.

Dietary lipid and gross energy affect protein utilization in the rare minnow Gobiocypris rarus

An 8-week feeding trial was conducted to detect the optimal dietary protein and energy, as well as the effects of protein to energy ratio on growth, for the rare minnow (Gobiocypris rarus), which are critical to nutrition standardization for model fish. Twenty-four diets were formulated to contain three gross energy (10, 12.5, 15 kJ/g), four protein (20%, 25%, 30%, 35%), and two lipid levels (3%, 6%). The results showed that optimal dietary E/P was 41.7-50 kJ/g for maximum growth in juvenile rare minnows at 6% dietary crude lipid. At 3% dietary lipid, specific growth rate (SGR) increased markedly when E/P decreased from 62.5 kJ/g to 35.7 kJ/g and gross energy was 12.5 kJ/g, and from 75 kJ/g to 42.9 kJ/g when gross energy was 15.0 kJ/g. The optimal gross energy was estimated at 12.5 kJ/g and excess energy decreased food intake and growth. Dietary lipid exhibited an apparent protein-sparing effect. Optimal protein decreased from 35% to 25%-30% with an increase in dietary lipid from 3% to 6% without adversely effecting growth. Dietary lipid level affects the optimal dietary E/P ratio. In conclusion, recommended dietary protein and energy for rare minnow are 20%-35% and 10-12.5 kJ/g, respectively.

First development of various vegetable-based diets and their suitability for abalone Haliotis tuberculata coccinea Reeve

Abstract To date, European abalone aquaculture relies mostly on locally harvested fresh seaweeds which nutritional quality and abundance vary greatly, hence affecting abalone growth. Abalone artificial diets generally include fishmeal, limiting their utilization in ecologically sustainable aquaculture and affecting abalone quality and acceptance by the consumers. A six month feeding trial was conducted to assess the nutritional value of four different dried seaweed meals: Ulva lactuca (Chlorophyta), Gracilaria cornea (Rhodophyta), Laminaria digitata (Phaeophyta) and Palmaria palmata (Rhodophyta), as ingredients to all-vegetable-based formulated feeds for abalone Haliotis tuberculata coccinea (33.1 ± 0.8 mm and 4.7 ± 0.6 g). A mixed fresh algae diet of G. cornea and U. Ulva rigida, reared in an Integrated Multi-Trophic Aquaculture (IMTA) system, served as control. Survival rates were very high (95–98%), regardless of the diet fed. Enriched fresh algae produced a significantly higher growth for H. tuberculata coccinea (169% weight gain) than all the artificial diets (49–84% WG). Comparison among abalone fed the different formulated diets showed that the inclusion of P. palmata improved growth, condition index and dietary protein utilization. On the contrary, the use of L. digitata markedly reduced the efficiency of dietary protein since the protein-related nutritional index (PER), the percentage of protein deposited in the foot muscle as well as the meat to shell ratio recorded for animals fed this diet were the lowest, despite a higher feed intake. Large differences were found in the FA profile of fresh algae as compared with the three formulated diets. The n-3/n-6 ratio was much higher in the fresh algae and, consequently, in the foot tissues of abalone fed this diet in comparison to the one of those fed the formulated ones. The elevated contents of 20:4n-6 in the abalone fed the experimental diets and 20:5n-3 in abalone fed the fresh algae, as well as their respective metabolites, suggest that abalone have the ability to desaturate and elongate LA to ARA and ALA to EPA. Further studies are required to improve the growth obtained with these vegetable based diets, especially concerning the use of different seaweed combinations and inclusion levels, as well as the diet processing methods to improve diet water stability. Statement of relevance Development of vegetable based diets for abalone.

Comparative analysis of the hepatopancreas transcriptome of grass carp (Ctenopharyngodon idellus) fed with lard oil and fish oil diets

n-3 highly unsaturated fatty acids (n-3 HUFAs) have been shown to suppress lipid accumulation and improve protein utilization in grass carp; however, little is known about the underlying molecular mechanism. Hence, we analyzed the hepatopancreas transcriptome of grass carp (Ctenopharyngodon idellus) fed either lard oil (LO) or fish oil (FO) diets. RNA-seq data showed that 125 genes were significantly up-regulated and 107 were significantly down-regulated in the FO group. Among them, 17 lipid metabolism related genes, 12 carbohydrate metabolism related genes, and 34 protein metabolism related genes were selected. Lipid metabolism related genes, such as very long-chain acyl-CoA synthetase (ACSVL), carnitine O-palmitoyltransferase 1 (CPT1) and carnitine–acylcarnitine translocase (CACT), were up-regulated in the FO group. But the genes of diacylglycerol O-acyltransferase 2 (DGAT2) and stearoyl-CoA desaturase (SCD) were down-regulated. Down-regulation of glycolysis related genes, such as 6-phosphofructokinase (PFK), phosphoglycerate kinase (PGK) and pyruvate dehydrogenase kinase (PDK), added with up-regulation of gluconeogenesis related genes, such as phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase), suggests lower utilization of carbohydrate of the FO group. Besides, dietary FO also influenced the protein metabolism related genes, such as up-regulation of genes involved in digestion of dietary protein, mRNA transcription, protein translation and amino acid utilization, down-regulation of genes involved in mRNA degradation and ubiquitination of protein. Interestingly, the up-regulation of mitochondrial uncoupling protein 2 (UCP2) and down-regulation of oxidative phosphorylation related genes (cytochrome c oxidase subunit 4 isoform 2 [COX4I2], HIG1 domain family member 1A [HIGD1A] and cytochrome-b5 reductase [CYB5R]) suggest that energy metabolism may be also influenced by dietary fatty acid composition. These findings presented here provide a comprehensive understanding of the molecular mechanisms governing the effects of fish oil in grass carp.

Starch and lipid in diets for douradoSalminus brasiliensis(Cuvier 1816): growth, nutrient utilization and digestive enzymes

Carbohydrates and lipids are the major and cheaper non-protein energy sources for fish diets. This study aimed at determining ideal relationship between dietary starch and lipids and their influence on digestive enzyme profile of juvenile dourado. Trials were set up in a closed-loop system with controlled temperature, dissolved oxygen, pH and total ammonia. Experimental extruded diets formulated to contain different starch (St) to lipids (Lip) ratio (St : Lip = 0 : 1, 0.3 : 1, 0.7 : 1, 1.0 : 1, 1.4 : 1, 2.0 : 1, 2.3 : 1 to 3.3 : 1) were fed to juvenile dourado (3.34 ± 0.16 g) and stocked into 30 polyethylene tanks (330 L, 30 fish per tank) in a completely randomized design with unbalanced repetition (n = 3 or 4), in two daily meals (1000 and 1530) until satiation, for 95 days. Dietary starch contents higher than 145.2 g kg-1 (St : Lip > 1.0 : 1.0) hampered the performance of fish, but, paradoxically, the inclusion of carbohydrates in the diet elicited better utilization of dietary protein and energy by the species. Fish adapted digestive enzyme profile to dietary starch contents through increasing secretion of alkaline proteases and non-specific lipases, but secretion of amylase was not altered. Physiological responses show the limitation of species on the use of dietary carbohydrates.

Legume grain-based supplements in dairy sheep diet: effects on milk yield, composition and fatty acid profile

With the aim to find protein sources that are free of genetically modified organisms, the effects of legume grain-based concentrates, used as alternatives of a mixed concentrate feed containing soybean, were evaluated on sheep milk production. Twelve lactating ewes were divided into four groups, fed hay and, according to a 4 × 4 Latin square design, supplied with 800 g/day of a commercial mixed concentrate feed (MCF) containing maize and soybean, or the same amount of isoprotein concentrates consisting of chickpea (CH), faba bean (FB), or pea (PE) mixed with barley. The ewes ingested more of the concentrates with legume grains than the MCF (702, 702, 678 vs 587 g/day DM for CH, FB, PE and MCF; P ≤ 0.001). Compared with CH, FB and PE resulted in greater (P ≤ 0.05) milk yield (710, 718 vs 654 g/day for FB, PE and CH, respectively), and led to a greater (P ≤ 0.05) efficiency of dietary protein utilisation for milk casein synthesis (94, 97 vs 87 g casein/kg crude protein intake for FB, PE and CH, respectively), whereas MCF resulted in intermediate levels of milk yield (677 g/day) and milk casein/crude protein intake (88 g/kg). Chickpea increased the milk content of trans-vaccenic and rumenic acids in comparison with FB and PE and, similarly to MCF, increased the milk content of linoleic acid, as well as total unsaturated fatty acids (24.3, 23.9 vs 17.2, 16.8 g/100 g fatty acid methyl esters for MCF, CH, FB and PE; P ≤ 0.001), thereby improving the potential health-promoting index. Legume grains can replace soybean in diets of dairy ewes, as they do not adversely affect milk yield and composition.

The Biological Value of Protein.

The biological value of a protein extends beyond its amino-acid composition and digestibility, and can be influenced by additional factors in a tissue-specific manner. In healthy individuals, the slow appearance of dietary amino acids in the portal vein and subsequently in the systemic circulation in response to bolus protein ingestion improves nitrogen retention and decreases urea production. This is promoted by slow absorption when only protein is ingested (e.g. casein). When a full meal is ingested, whey achieves slightly better nitrogen retention than soy or casein, which is very likely achieved by its high content of essential amino acids (especially leucine). Elderly people exhibit 'anabolic resistance' implying that more protein is required to reach maximal rates of muscle protein synthesis compared to young individuals. Protein utilization in inflammatory or traumatic conditions increases substantially in the splanchnic tissues containing most of the immune system, and in wounds and growing tissues. This happens especially in the elderly, which often suffer from chronic inflammatory activity due to disease, physical inactivity and/or the aging process itself. Consequently, the proportion of protein absorbed in the gut and utilized for muscle protein synthesis decreases in these situations. This compromises dietary-protein-induced stimulation of muscle protein synthesis and ultimately results in increased requirements of protein (∼1.2 g/kg body weight/day) to limit gradual muscle loss with age. To optimally preserve muscle mass, physical exercise is required. Exercise has both direct effects on muscle mass and health, and indirect effects by increasing the utilization of dietary protein (especially whey) to enhance rates of muscle protein synthesis.

The Effects of Partial Replacement of Soybean Meal by Xylose-Treated Soybean Meal in the Starter Concentrate on Performance, Health Status, and Blood Metabolites of Holstein Calves

The objective was to study the effects of partial replacement of soybean meal (SBM) with xylose-treated SBM (XSBM) as a source of rumen undegradable protein (RUP) in the starter concentrate of calves on performance, health status and selected blood metabolites. Twenty-one female Holstein dairy calves (body weight=39.6±2.3 kg) were randomly assigned to 3 groups (n=7 each): i) starter concentrate with 25% SBM [control (CTR)]; ii) starter concentrate with 17.5% SBM +7.5% XSBM (7.5XSBM); and iii) starter concentrate with 12.5% SBM+12.5% XSBM (12.5XSBM). Calves received 2 L of milk twice daily, with ad libitum access to starter concentrates from d 4 until weaning (d 56). Performance and health status were recorded throughout the experiment. Blood samples collected on d 4, 35 and 56 were assayed for concentrations of glucose, total protein (TP), and plasma urea nitrogen (PUN). Starter intake (560, 400, and 420 g/d for CTR, 7.5XSBM, and 12.5XSBM, respectively), average daily gain (0.67, 0.6 and 0.57 kg/d), and feed to gain ratio (0.83, 0.67, and 0.74) were affected by treatments (P<0.05). Hearth girth, height at withers, body length, rectal temperature, faecal score, and respiratory score did not differ among treatments. Mean plasma glucose and TP were not affected by treatments, whereas PUN in the 12.5XSBM group was lower than in the other groups (P<0.05). In conclusion, the present results showed that partial replacement of SBM by XSBM may improve efficiency of dietary protein utilisation in pre-weaned calves, which warrants further studies.

Serum-derived Bovine Immunoglobulin Isolate: A New Medical Food for the Clinical Dietary Management of Enteropathy

Purpose: The intestinal epithelial barrier is critical in maintaining gut homeostasis. The loss of structural and functional integrity of the intestinal epithelial barrier increases permeability, which can allow greater antigenic penetration and subsequent activation of mucosal immune responses. The related inflammatory responses can contribute to several gastrointestinal (GI) disorders or enteropathies. The clinical manifestations vary among enteropathies, though abdominal pain or discomfort, bloating, flatulence, and altered bowel habits are common. The complex interactions between immune and nervous systems with the gut require a multifactorial, pathophysiological approach rather than targeting a single receptor/effector pathway. Methods: A number of studies suggest a potential role for serum-derived bovine immunoglobulin/protein isolate (SBI) to provide distinct nutrition in enteropathies, which decrease absorption and utilization of specific nutrients, alongside traditional medications that target specific aspects of the disease. SBI is a prescription medical food, specially formulated to be consumed orally or enterally under the medical supervision for the dietary management of enteropathy. It is affirmed as generally recognized as safe with no FDA objections. SBI has been shown in various nonclinical and clinical studies to have multiple mechanisms of action. These include: neutralizes bacterial endotoxins, balances intestinal microbiota, maintains integrity of the tight junctions, reduces cellular and soluble markers of immune activation, increases anti-inflammatory markers, and improves intestinal barrier dysfunction affected by inflammation. Results: Non-clinical trials have confirmed that plasma proteins containing immunoglobulins affects cellular immune activation, resulting in improved intestinal mucosal barrier function, reduced inflammation and diarrhea, as well as improved dietary protein utilization. In a HIV clinical study, SBI has been reported to decrease loose or watery bowel movements and increase absorptive function. Early studies in patients with IBS-D, malnutrition, or HIV enteropathy have noted improvements in nutrient retention and GI symptoms. Conclusion: The nutritional therapeutic approach aimed at restoring the mucosal membrane homeostasis and inhibiting intestinal immune activation through multiple mechanisms may be beneficial in GI disorders. Non-clinical and clinical studies demonstrate that nutritional management with SBI facilitates the restoration of the intestinal epithelial barrier and immune activation, thereby managing GI symptoms and improving nutritional status. SBI may prove beneficial in the nutritional management of diseases associated with intestinal inflammation.

Effects of dietary l-lysine intake on the intestinal mucosa and expression of CAT genes in weaned piglets

The objective of this study was to evaluate effects of dietary L-lysine on the intestinal mucosa and expression of cationic amino acid transporters (CAT) in weaned piglets. Twenty-eight piglets weaned at 21 days of age (Duroc × Landrace × Yorkshire; 6.51 ± 0.65 kg body weight) were assigned randomly into one of the four groups: Zein + LYS (zein-based diet + 1.35 % supplemental lysine), Zein - LYS (zein-based diet), NF (nitrogen-free diet), and CON (basal diet). The experiment lasted for 3 weeks, during which food intake and body weight were recorded. At the end of the trial, blood was collected from the jugular vein of all pigs, followed by their euthanasia. Dietary supplementation with lysine enhanced villus height and crypt depth in the jejunum (P < 0.05). Jejunal mRNA levels for the b(0,+)-AT, y(+)LAT1 and CAT1 genes were greater (P < 0.05) in the Zein + LYS group than in the control, and the opposite was observed for CAT1. Dietary content of lysine differentially affected intestinal CAT expression to modulate absorption of lysine and other basic amino acids. Thus, transport of these nutrients is a key regulatory step in utilization of dietary protein by growing pigs and lysine in the diet influences the expression of amino acid transporters in the small intestine.

Lipid digestion, absorption and uptake in Solea senegalensis

Dietary lipids are the major energy source for metabolic purposes in most fish species, and improve dietary protein utilization for growth. In a previous study we have reported a low tolerance of Senegalese sole juveniles to dietary lipid levels and suggested a maximal dietary inclusion level of 8% lipids for both optimal growth and nutrient utilization. The mechanisms behind this apparent poor utilization of the dietary lipids are still to be elucidated. The primary aim of the present study was to investigate the overall process of digestion and lipid absorption in relation to dietary lipid levels.Triplicate groups of twenty fish (mean initial mass 29g) were fed two isonitrogenous diets (54% of protein dry matter basis) with different lipid levels (L4 and L17, 4 and 17% lipids dry matter basis), for 88days. Protein and lipid apparent digestibility coefficients as well as lipase activity were similar in both groups suggesting that Solea senegalensis has the ability to digest equally well a low fat or a high fat diet. Plasma triglyceride concentrations were significantly higher 5 and 16h after feeding in fish fed the L17 compared to those fed L4, following dietary lipid supply, demonstrating effective lipid absorption. Expression of proteins related to lipid transport (microsomal triglyceride transfer protein), trafficking (Fatty acid binding protein 11) and fatty acid uptake (VLDL-r) was significantly higher in liver of fish fed the high fat diet 16h after the meal, but remained unchanged in muscle. In conclusion, it seems that high fat diets do not impair lipid digestion and absorption.

Serum‐derived bovine immunoglobulin isolate (SBI) as a potential therapy for inflammatory bowel disorders (IBD)

Cytokine‐mediated dysfunction of the intestinal mucosal barrier is observed during the active phase of IBD. SBI may reduce its impact by reducing excessive pro‐inflammatory cytokine expression, such as TNFα, INFγ, and interleukins (eg, IL‐1, IL‐6). For example, mdr1a knockout mice prone to intestinal mucosal barrier alterations (a genetic model for IBD) who received SBI had lower levels of IL‐6 and IL‐17 in the mucosa during the onset of colitis.Research demonstrates that SBI survives initial digestive processes, improving gastrointestinal (GI) function and morphology in a clinically significant way. Animal studies confirm SBI improves cellularity of the lamina propria of the small intestine, resulting in improved mucosal barrier function, reduced inflammation and diarrhea, and improved dietary protein utilization through increased absorption, reduced permeability and mitotic activity, increased villus heights, with improved weight gain and bone density. SBI decreased watery bowel movements and increased nutrient absorption/retention in HIV patients, and was well tolerated. Early studies in patients with IBS‐D, malnutrition or HIV enteropathy demonstrated improved GI symptoms. In toto, the accumulated evidence suggests SBI is beneficial for inflammatory GI diseases such as Crohn's and ulcerative colitis and demonstrates strongly the need for additional research. Study funded by Entera Health.