Indispensable Amino Acid Requirements Research Articles

Digestible indispensable amino acid score (DIAAS): 10 years on.

The objective of the review is to revisit the findings of the 2011 Food and Agriculture Organization of the United Nations (FAO) Expert Consultation on Dietary Protein Quality Evaluation in Human Nutrition, and to report on progress on uptake of the findings. It is evident that since 2011 there has been a concerted research effort to enhance an understanding of the protein quality of foods. The validity of the growing pig ileal protein digestibility assay has been confirmed and numerous studies reported using the growing pig as a model to give true ileal amino acid digestibility values for foods as consumed by humans. This has allowed for the determination of digestible indispensable amino acid scores (DIAAS) for a range of foods. A new non-invasive true ileal amino acid digestibility assay in humans which can be applied in different physiological states, called the dual-isotope assay, has been developed and applied to determine the DIAAS values of foods. It is concluded that DIAAS is currently the most accurate score for routinely assessing the protein quality rating of single source proteins. In the future, the accuracy of DIAAS can be enhanced by improved information on: the ideal dietary amino acid balance including the ideal dispensable to indispensable amino acid ratio; dietary indispensable amino acid requirements; effects of processing on ileal amino acid digestibility and lysine bioavailability. There is a need to develop rapid, inexpensive in vitro digestibility assays. Conceptual issues relating DIAAS to food regulatory claims, and to holistic indices of food nutritional and health status are discussed. The first recommendation of the 2011 Consultation regarding treating each indispensable amino acid as an individual nutrient has received little attention. Consideration should be given to providing food label information on the digestible contents of specific indispensable amino acids.

Consideration of utilizable amino acid content in the context of dietary protein quality assessment

AbstractCurrent evaluation systems for protein quality focus only on indispensable amino acids (IAAs) and do not consider the dispensable amino acids (DAAs). However, at excess levels of IAAs, DAAs may become limiting. Here, we used published ileal amino acid digestibility data determined in growing pigs and currently assumed protein and IAA recommendations to estimate utilizable, oxidized, and non‐absorbed amino acids in different dietary protein and to compare these utilizable amino acid values to digestible indispensable amino acid score (DIAAS) values. For dietary protein sources with a DIAAS value <90, the amount of calculated utilizable amino acids increased proportionally with the DIAAS value according to “utilizable amino acids (mg/g protein) = DIAAS × 10”; for dietary protein sources with a DIAAS value >90, the amount of utilizable amino acid stays within the range 800–1000 mg/g protein. Cereals contained the lowest levels of utilizable amino acids and the highest amount of oxidized amino acids. Dairy and meat have the highest amount of utilizable amino acids followed by nuts and pulses. For many mixtures of protein sources, the highest value for utilizable amino acids, which considers both IAAs and DAAs, occurred at a different ratio of protein sources than the maximum DIAAS value, which only considers IAAs. From this theoretical study and based on the assumptions made, we conclude that estimation of utilizable amino acids from data typically reported in DIAAS studies further enables complementary insights next to DIAAS values. Careful consideration of protein and IAA requirements is critical in further work.

Mealworm larvae (Tenebrio molitor) and crickets (Acheta domesticus) show high total protein in vitro digestibility and can provide good-to-excellent protein quality as determined by in vitro DIAAS.

Edible insects, such as mealworms (Tenebrio molitor larvae; TM) and crickets (Acheta domesticus; AD), are a sustainable, protein-dense novel food with a favorable amino acid profile, which might be an alternative to animal proteins. To assess the protein quality of TM and AD, we assessed the digestible indispensable amino acid scores (DIAAS), considering individual amino acids and their ileal amino acid digestibility, using an in vitro model based on the INFOGEST digestion protocol. In addition, we evaluated if various processing and food preparation steps influenced the in vitro digestibility of individual amino acids and the in vitro DIAAS values of TM and AD and compared them to chicken breast as a reference of excellent protein quality. The total protein in vitro digestibility ranged from 91 to 99% for TM and from 79 to 93% for AD and was negatively affected by oven-drying and, to a lesser extent, by chitin-reduction. The in vitro DIAAS values were 113, 89, and 92 for chicken, blanched TM, and blanched AD, respectively, when considering the indispensable amino acid (IAA) requirements of young children between 6 months and 3 years. Across different processing and food preparation methods, the in vitro DIAAS values ranged between 59 and 89 for TM and between 40 and 92 for AD, with the lowest values found in chitin-reduced insects. Due to their similarities to chicken regarding protein composition, total protein in vitro digestibility, and in vitro DIAAS values, TM and AD might be an alternative to traditional animal proteins, provided that suitable processing and food preparation methods are applied. Our in vitro DIAAS results suggest that TM and AD can thus be considered good-quality protein sources for children older than 6 months. The DIAAS calculations are currently based on crude protein (total nitrogen × 6.25), resulting in an overestimation of insect protein content, and leading to an underestimation and potential misclassification of protein quality. The in vitro model applied in this study is a valuable tool for product development to optimize the protein quality of edible insects. Further studies are required to assess the in vivo DIAAS of insects in humans.

Pattern of Amino Acid Requirements in Humans: An Interspecies Comparison using Published Amino Acid Requirement Recommendations

We undertook an interspecies comparison of essential (indispensable) amino acid requirements, in relation to those for total protein, to examine whether the current, internationally proposed human amino acid requirement patterns are significantly different from those of other animals. Data were compiled in their original form and then expressed as mg amino acid/g total dietary protein (N × 6.25) required (amino acid requirement pattern). Patterns of requirements within the various species were organized according to four, arbitrary age-developmental groupings (very young, early growth, growth and mature), and these were compared with the requirements for (a) human infants, (b) 2–5 year old children, (c) 10–12 year old children and (c) adults, respectively. Statistical comparisons determined if significant differences existed between humans and other species, at apparently similar age-development stages, for both the total and for individual indispensable amino acids. The sum of the specific indispensable amino acid requirements for humans was significantly different than that for other species at infancy, growth and adulthood; the greatest differences, however, were for the amino acid requirement pattern in adulthood. The change between the very young and adult was the greatest for humans. Some of this difference might be due to experimental factors, including the biological status of a species within the arbitrary groupings described and the criteria used to determine “requirements.” Nevertheless, it is difficult to escape the conclusion that the current international human amino acid requirements, for adults in particular, appear to be anomalous when judged against data for other animal species.

Carcass Characteristics, Meat Quality and Nutritional Composition of Kadaknath, a Native Chicken Breed of India.

The study was carried out to investigate the carcass and meat quality traits and nutritional profile of the meat of the Kadaknath, a unique native chicken breed in comparison with commercial broilers. The yield of the carcass, breast and giblets of the Kadaknath was lesser (p < 0.01), while that of the legs, wings, back, and neck was higher (p < 0.01) than broilers. The meat of the Kadaknath was significantly (p < 0.0001) darker (42.44, 50.92) and more yellow (6.23, 8.99) than broilers. The decline in pH of the meat was lower (p < 0.001) in the Kadaknath compared to broilers. Kadaknath meat had more protein and less fat, moisture and ash content than broilers (p < 0.01). Furthermore, it was richer (p < 0.01) in 11 amino acids, including those which are known to impart a sweet and umami taste, than the meat of broilers (3 amino acids). Both genotypes were almost similar in meeting the daily requirements of indispensable amino acids of adult human. The study concluded that the Kadaknath differed in carcass and meat quality characteristics from the broilers, and the nutritional quality of Kadaknath meat in terms of high protein and less fat and higher content of amino acids (tasty type) was better in Kadaknath meat as compared to broiler meat.

Amino acid oxidation methods to determine amino acid requirements: do we require lengthy adaptation periods?

Determination of indispensable amino acid (IAA) requirements necessitates a range of intakes of the test IAA and monitoring of the physiological response. Short-term methods are the most feasible for studying multiple intake levels in the same individual. Carbon oxidation methods measure the excretion of 13CO2 in breath from a labelled amino acid (AA) in response to varying intakes of the test AA following a period of adaptation. However, the length of adaptation to each AA intake level has been a source of debate and disagreement among researchers. The assertion of the minimally invasive indicator amino acid oxidation (IAAO) technique is that IAA requirements can be estimated after only a few hours (8 h) of adaptation to each test AA intake, suggesting that adaptation occurs rapidly in response to dietary adjustments. On the contrary, the assertion of most other techniques is that 6-7 d of adaptation is required when determining IAA needs. It has even been argued that a minimum of two weeks is needed to achieve complete adaptation. This review explores evidence regarding AA oxidation methods and whether long periods of adaptation to test IAA levels are necessary when estimating IAA requirements. It was found that the consumption of experimental diets containing lower test IAA intake for greater than 7 d violates the terms of a successful adaptive response. While there is some evidence that short-term 8 h IAAO is not different among different test amino acid intakes up to 7 d, it is unclear whether it impacts assessment of IAA requirements.

Digestible indispensable amino acid scores of animal and plant ingredients potentially used in dog diet formulation: how this protein quality metric is affected by ingredient characteristics and reference amino acid profile.

The ability of a diet or an ingredient to satisfy the indispensable amino acid (IAA) requirements of an individual is a reflection of protein quality (PQ). The concept of PQ is gaining recognition in the pet food industry as a way to identify candidate ingredients for diet formulation. The objective of this report was to use IAA digestibility data from swine and cecectomized rooster assays to generate digestible IAA scores (defined herein as DIAAS-like values) to predict the PQ of ingredients used in dog diets. However, as PQ equation development relies on a reference IAA profile, which is intended to be based on the physiological requirements of a specific population, we sought to generate DIAAS-like values using IAA requirements established by the National Research Council (NRC) as well as practical IAA recommendations presented by the Association of American Feed Control Officials (AAFCO) and European Pet Food Industry Federation (FEDIAF), to assess how these profiles may affect PQ. In total, 30 animal (75 unique inputs) and 27 plant ingredients (94 unique inputs) satisfied all inclusion criteria to be used in the final data set. Ingredients were initially categorized as animal or plant, and further categorized based on AAFCO Official Common and Usual Names and Definitions of Feed Ingredients to allow for additional, more distinct comparisons to be made. Data were analyzed using PROC GLIMMIX in SAS, with ingredient reference as a random effect, and ingredient category, regulatory body, and life stage as fixed effects. As expected, differences were observed in DIAAS-like values for nearly all ingredients and ingredient categories when determined using NRC, AAFCO, or FEDIAF IAA requirements or recommendations as the reference pattern. Moreover, applying reference patterns based on NRC adult maintenance IAA requirements consistently produced the lowest DIAAS-like values. Ultimately, while future studies assessing PQ should utilize NRC minimal requirements, individual ingredient and ingredient category differences in DIAAS-like values when using AAFCO and FEDIAF recommendations underpin the different regulatory approaches to establishing dietary nutrient recommendations that exist globally and support the need for harmonization of dietary recommendations.

513 Late-Breaking: Effects of Dietary Protein Content and Crystalline Amino Acid Supplementation Patterns on Gut Health of Weaned Pigs Raised Under Different Sanitary Conditions

Abstract The objective of this experiment was to investigate the effects of dietary crude protein (CP) content and crystalline amino acids (CAA) supplementation patterns on the histomorphology, immune response, and microbial metabolites in weaned pigs under clean (CSC) or unclean sanitary conditions (USC). One hundred forty-four piglets (6.35 ± 0.63 kg BW) were assigned to 1 of 3 diets: a high CP (HCP; 21%) and two low CP (LCP; 18%) diets supplemented with 10 crystalline indispensable amino acids (IAA) to meet all IAA requirements or only 6 IAA (Lys, Met, Thr, Trp, Val, and Ile) to meet IAA requirements except for Leu, His, and Phe. Each treatment had 8 replicates per sanitary condition with 3 pigs per pen. The CSC room was cleaned and washed weekly, whereas the USC room remained unwashed throughout the experiment and had sow manure spread in the pens. Data were analyzed using the MIXED procedure of SAS with orthogonal contrasts. Pigs fed the LCP diets had longer (P < 0.05) jejunal villi and higher villus height to crypt depth ratios than those fed the HCP diet. No significant difference is found in histomorphology between pigs fed LCP diets with different CAA supplementation patterns. Pigs raised under USC had greater (P < 0.05) plasma interleukin (IL)-10 and IL-6 concentrations and reduced (P < 0.05) plasma tumor necrosis factor-alpha concentration. Also, the LCP diets resulted in a greater (P < 0.05) plasma IL-10 concentration. Interactions (P < 0.05) between sanitation and dietary CP content were observed for goblet cell density and acetate and total volatile fatty acids contents in the jejunum. In conclusion, CAA supplementation patterns did not affect gut morphology in weaned pigs. Feeding LCP diets to weaned pigs improved gut morphology and microbial metabolites in jejunum under USC and ameliorated systemic inflammation induced by USC.

217 Effects of Dietary Protein Content and Crystalline Amino Acid Supplementation Patterns on Growth Performance of Weaned Pigs Raised Under Different Sanitary Conditions

Abstract The objective of this experiment was to determine the effects of dietary crude protein (CP) content and crystalline amino acids (CAA) supplementation patterns on the growth performance of weaned pigs under clean (CSC) or unclean sanitary conditions (USC). One hundred forty-four piglets (6.35 ± 0.63 kg BW) were housed under CSC or USC for 3 wk and assigned to 1 of 3 diets: a high CP (HCP; 21%) and two low CP (LCP; 18%) diets supplemented with 10 crystalline indispensable amino acids (IAA) to meet all IAA requirements or only 6 IAA (Lys, Met, Thr, Trp, Val, and Ile) to meet IAA requirements except Leu, His, and Phe. Each treatment had 8 replicates (3 pigs per pen) per sanitary condition. The CSC room was cleaned and washed weekly. For the USC room, sow manure was spread and remained unwashed. Data were analyzed using the MIXED procedure of SAS with orthogonal polynomial contrasts. Pigs raised under USC had reduced (P < 0.05) ADG and G:F in wk 2, but overall, no difference was found between sanitary conditions due to contrary results in wk 3. Overall, ADG and ADFI were not affected but G:F tended (P < 0.10) to be lower for USC pigs. Also, G:F did not differ between HCP (0.79) and LCP (0.81) under CSC, however, LCP interactively decreased (P < 0.05) G:F to 0.75 compared to 0.83 in HCP under USC. The CAA supplementation patterns did not influence growth except reduced (P < 0.05) ADFI in wk 3. Pigs fed the HCP diet had higher (P < 0.05) fecal scores throughout the experiment than those fed LCP diets under both sanitary conditions. In conclusion, overall growth performance did not differ between HCP and LCP under CSC, but LCP diets reduced G:F under USC. The fecal score decreased in LCP diets regardless of sanitary conditions.

Protein Intakes in Rural India – Implications of Protein Quality

A prevalence of 18% Low Birth Weight (LBW), 38% stunting in <5y children, and 18% sarcopenia in adults have been recently reported in India. These could partly be due to a poor-quality protein intake, which could support positive birth outcomes, linear growth in children and maintenance of the adult skeletal muscle mass with appropriate exercise. Quality protein is a highly digestible protein with adequate quantity of Indispensable Amino Acids (IAA). The measurement of risk of deficient quality protein intake requires knowledge of IAA requirements and their digestibility from different food proteins. The present analyses, using dietary intake data of different age groups from the latest National Nutrition Monitoring Bureau rural survey, showed that the protein quality of rural Indian diets was suboptimal and had considerable impact on the risk of quality protein deficiency, which varied from 14 to 80% among different age groups. Modest additions of animal source foods (such as milk and egg) could alleviate the risk of quality protein deficiency in the population. Dietary protein quality should be considered while evaluating dietary interventions and framing the policy of supplementary nutrition programs for vulnerable populations.

Use of the precision-fed cecectomized rooster assay to determine standardized amino acid digestibility, true metabolizable energy content, and digestible indispensable amino acid scores of plant-based protein by-products used in canine and feline diets.

Traditionally, protein by-products from oil seeds and cereal grains have been used in pet foods as sustainable, inexpensive, and protein-rich ingredients. However, the on-going demonization of soy- and corn-based ingredients continue to hinder their use in pet food and treat formulations. Ideally, the further demonstration of their protein quality and nutrient composition may encourage their favorable return as acceptable ingredients in pet foods and treats. Therefore, the objectives of this study were to determine the macronutrient composition, indispensable amino acid profile, standardized amino acid digestibility, true metabolizable energy content corrected for nitrogen (TMEn), and digestible indispensable amino acid scores (DIAAS-like) of soy flakes (SF), peanut flour (PF), soybean meal (SBM), and corn gluten meal (CGM). Standardized amino acid digestibility was assessed using the precision-fed cecectomized rooster assay. All test ingredients demonstrated a profile of highly digestible indispensable amino acids except for lysine in PF, which was lowest (P < 0.05) at 45.5%. The SBM and CGM had the highest (P > 0.05) digestibilities of indispensable amino acids. A DIAAS-like value was calculated for each ingredient using either AAFCO (2020) recommended values or NRC (2006) recommended allowances as the reference protein pattern. For adult dogs compared to AAFCO recommended values, the first-limiting amino acid was lysine for PF and CGM but it was methionine for SF and SBM. For adult cats compared to AAFCO recommended values, the first-limiting amino acid was lysine for PF and CGM but it was threonine for SF. There was no first-limiting amino acid in SBM for cats as DIAAS-like values were over 100% for all indispensable amino acids. The TMEn values were highest (P < 0.05) for PF and CGM (4.58 and 4.31 kcal/g [dry matter basis], respectively). The protein quality of these plant-based protein by-products reflects their value as nutritional ingredients for canine and feline diets. However, the prior processing of these by-products must be considered before exposing them to additional processing methods, such as extrusion. Additionally, the inclusion of complementary proteins or supplemental amino acids will be needed to meet all indispensable amino acid requirements for a portion of nutritionally complete and balanced pet food.

Protein intakes of pregnant women and children in India-protein quality implications.

The recent National Family Health Survey (NFHS‐4, 2016) reports a national average of 18% for low birthweight (LBW) and 38% for stunting in children <5 years. Nutrition and environmental influences (chronic enteric pathogenic exposure through poor water, sanitation, and hygiene) are two critical factors that impact the health outcomes of the populxation. This is particularly relevant for vulnerable age groups such as pregnant women and children <5 years, who bear long‐lasting and intergenerational consequences of impoverished nutrition and suboptimal living conditions. The present review provides, for the first time, an analysis of indispensable amino acid (IAA) requirements for pregnant women, separately for the second and third trimesters, using protein accretion data from a recent Indian study. Furthermore, using these estimates for pregnancy, and the current IAA requirements for young children, the quality of protein was assessed in Indian diets consumed by pregnant women and children (1–3 and 4–6 years) from national representative rural National Nutrition Monitoring Bureau survey. The assessment was considered in the context of an adverse environment and in relation to outcomes such as LBW, stunting, and underweight. Finally, an assessment was made of the proportion of the surveyed population at risk of dietary quality protein inadequacy and implications for planning nutrition intervention programmes. Specifically, state‐wise estimates of the risk of quality protein inadequacy are provided, in addition to evaluations of additional dietary supplementation, which could inform the policy of supplementary nutrition programmes to improve health outcomes.

Estimation of L-lysine Requirement by Indicator Amino Acid Oxidation Method Using Random Effects Model

In recent years, it has been suggested that the method for determining the requirements for indispensable (essential) amino acids be changed from the nitrogen balance method to the tracer methods. In particular, the indicator amino acid oxidation (IAAO) method has been implemented. Although the requirements for indispensable amino acids have been reported in several independent trials, no reported study has statistically integrated these data. In addition, the requirement as obtained from the IAAO method reported to date is the estimated average requirement (EAR), which will be met nutrient requirements in 50% of population only; thus, the risk of deficiency cannot be ruled out from a nutritional perspective. In this study, we statistically synthesized the data of multiple required amounts of lysine obtained by the IAAO method and attempted to accurately estimate the EAR. Further, we estimated the recommended dietary allowance (RDA) value from the obtained estimated EAR value. Analysis using a random effects model estimated that the EAR of lysine in healthy adults was approximately 37 mg/kg (95% CI: 31.2–42.5). In addition, the RDA was estimated to be about 46 mg/kg. These values are higher than the previously reported value of 30 mg/kg.

Can the digestible indispensable amino acid score methodology decrease protein malnutrition.

Protein undernutrition is a serious global problem that results in stunted growth, disease, and premature death in millions of people annually. Protein deficiency is caused by a deficiency in specific indispensable amino acids and efforts to alleviate protein malnutrition, therefore, need to focus on the provision of adequate quantities of digestible indispensable amino acids. The digestibility of amino acids is most correctly determined at the end of the small intestine, and digestibility values obtained using this approach are termed “ileal digestibility values.” The total protein provision to an individual is based on the sum of digestible indispensable amino acids consumed in a meal. The protein quality of a single ingredient is less important than the quality of the mixed meal that is consumed. To assist in calculating the protein quality of meals for humans, the FAO recommends that a system called the “Digestible Indispensable Amino Acid Score” or DIAAS be used. This system is based on the ileal digestibility of each amino acid in individual protein foods, but allows for the calculation of the quality of a meal consisting of a number of protein foods. The system can then be used to assess the quality of total protein intake consumed as a meal. Comparison of this value to the requirements for indispensable amino acids by humans can be used to estimate an individual’s protein status.

Significant Amounts of Functional Collagen Peptides Can Be Incorporated in the Diet While Maintaining Indispensable Amino Acid Balance.

The results of twenty years of research indicate that the inclusion of collagen peptides in the diet can lead to various improvements in health. According to the current protein quality evaluation method PDCAAS (Protein Digestibility-corrected Amino Acid Score), collagen protein lacks one indispensable amino acid (tryptophan) and is therefore categorized as an incomplete protein source. Collagen protein displays a low indispensable amino acid profile, yet as a functional food, collagen is a source of physiologically active peptides and conditionally indispensable amino acids that have the potential to optimize health and address physiological needs posed by aging and exercise. The objective of this study was to determine the maximum level of dietary collagen peptides that can be incorporated in the Western pattern diet while maintaining its indispensable amino acid balance. Iterative PDCAAS calculations showed that a level as high as 36% of collagen peptides can be used as protein substitution in the daily diet while ensuring indispensable amino acid requirements are met. This study suggests that the effective amounts of functional collagen peptides (2.5 to 15 g per day) observed in the literature are below the maximum level of collagen that may be incorporated in the standard American diet.

Edible caterpillars of Imbrasia truncata and Imbrasia epimethea contain lipids and proteins of high potential for nutrition

Imbrasia truncata and I. epimethea caterpillars were evaluated as dietary protein and lipid sources. They contained approximately 7.0 g/100 g fresh weight (FW) of lipids and 20.0 g/100 g FW of proteins calculed with determined nitrogen to protein conversion factors: 6.01 ± 0.21 and 6.27 ± 0.15 for I. truncata and I. epimethea, respectively. Unsaturated fatty acids represented about 2.63 ± 0.21 g/100 g FW for I. truncata and 3.24 ± 0.21 g/100 g FW for I. epimethea, with α-linolenic acid as major fatty acid (around 1.88 ± 0.15 g/100 g FW for I. truncata 2.17 ± 0.13 g/100 g FW for I. epimethea) and very low n-6/n-3 ratios: 0.15 (I. truncata) and 0.27 (I. epimethea). Polar lipids (phospholipids and glycolipids + sulfolipids), representing between 4 and 6% of lipids, contained little amounts of arachidonic acid (C20:4n-6). The major tocopherol isomer was α−tocopherol in I. truncata (0.52 ± 0.08 g/100 g FW) and γ−tocopherol in I. epimethea (1.00 ± 0.08 g/100 g FW). The proteins of both insect included all indispensable amino acids at amounts (mg/g protein) higher than the indispensable amino acid requirement patterns recommended by WHO/FAO/UNU (2007). In conclusion, Imbrasia caterpillars exhibit a great nutritional potential due to the presence of good quality proteins and healthy fat

Protein quality & amino acid requirements in relation to needs in India.

The relevance of protein and its constituent amino acids (AAs) in the structure and function of the human body is well known. Accumulating evidence has conferred specific functional and regulatory roles for individual AAs, adding relevance to their requirements across different age groups. The methods for measuring AA requirements have progressed from the classical nitrogen balance to the current stable isotope-based AA balance methods. Requirements of most of the indispensable AA (IAA) have been estimated in healthy Indian population by the best available balance method and has shown to be higher than earlier 1985 WHO/FAO/UNU (World Health Organization/Food and Agriculture Organization/United Nations University) recommendations. In addition, potential changes in the requirement, through adaptation to chronic undernutrition or to infection, have also been evaluated. In 2007, the WHO/FAO/UNU released a recommendation that increased the daily IAA requirement, based on primary evidence from Indian balance studies. This meant that to ensure that the new IAA requirements were met, individual foods or mixed diets needed to be assessed for their protein quality, or their ability to deliver the required amount of IAA. The recent FAO report on protein quality evaluation recommends the use of a new chemical AA score, the digestible IAA score (DIAAS), to replace the earlier protein digestibility corrected AA score. The DIAAS requires the determination of individual AA digestibility at the ileal level. A minimally invasive dual stable isotope tracer-based approach has been developed in India and has been used to determine digestibility of various foods in Indian adults and children. The increase in IAA requirements and subsequent protein quality requirements have implications for national regulatory frameworks, growth and development, and in turn, for economic and agricultural policy.

Consideration of insects as a source of dietary protein for human consumption.

Consumption of sufficient dietary protein is fundamental to muscle mass maintenance and overall health. Conventional animal-based protein sources such as meat (ie, beef, pork, lamb), poultry, fish, eggs, and dairy are generally considered high-quality sources of dietary protein because they meet all of the indispensable amino-acid requirements for humans and are highly digestible. However, the production of sufficient amounts of conventional animal-based protein to meet future global food demands represents a challenge. Edible insects have recently been proposed as an alternative source of dietary protein that may be produced on a more viable and sustainable commercial scale and, as such, may contribute to ensuring global food security. This review evaluates the protein content, amino-acid composition, and digestibility of edible insects and considers their proposed quality and potential as an alternative protein source for human consumption.

Dietary histidine requirement and physiological effects of dietary histidine deficiency in juvenile red drum Sciaenop ocellatus

In order to develop nutritious and cost-effective diets, the amino acid requirements of cultured fish species must be quantified. Several indispensable amino acid requirements of red drum Sciaenops ocellatus have already been reported; however, its requirement for histidine (His) has yet to be quantified. The aims of the present studies were to determine the minimum dietary His requirement of juvenile red drum and the physiological effects of His deficiency. A basal diet was prepared using lyophilized red drum muscle as an intact protein (10.5% of dietary protein) supplemented with crystalline amino acids (excluding His) to provide a total of 35% crude protein (CP) in the diet. Five isonitrogenous and isoenergetic experimental diets were prepared by supplementing the basal diet (0.3g His/100g dry diet) with increasing amounts of His (0.5, 0.7, 0.9, 1.1, 1.3g/100g dry diet). These diets were fed to triplicate tanks of juvenile red drum (initial average weight of 0.98±0.08g/fish) for 6weeks in feeding trial 1 to quantify the minimum dietary His requirement. His level had significant effects on relative weight gain, feed efficiency ratio, protein efficiency ratio, and plasma free His. According to quadratic broken-line regression on relative weight gain percentage, the dietary His requirement was 0.59 (±0.15) g/100g dry diet (1.6% of CP). Feeding trial 2 was performed to further examine His deficiency in red drum. In that trial, the basal diet and a His-supplemented diet (~1.2g/100g dry diet) were fed to juvenile red drum (initial average weight of 1.53±0.08g/fish) in triplicate tanks for 8weeks. Cataracts were found in 16.7% of eyes from fish fed the basal diet while no fish in the supplemented group developed cataracts. His-supplemented fish were found to have higher erythrocyte fragility than those fed the basal diet. Based on these results, the His requirement of red drum was defined and His deficiency was observed to affect blood parameters and increase the possibility of cataract development.

Amino Acid Requirements of Gilthead Bream (&lt;i&gt;Sparus aurata&lt;/i&gt;) Juveniles

In one trial 120 gilthead bream fingerlings received tow different feed mixtures containing two different levels of protein (diet A.400 and B 360 gkg-1). The average initial live weight was about 2.2 ±0.1 g fish-1 in each replicate of all treatments. Twenty fish per aquarium were stocked randomly in 6 glass aquaria (120 l each). Fish were fed with experimental diets at rate 8 % of the body weight daily. The amino acids (AA) content was in the diets, whole fish and muscle at the end of the growth period (60 days). The results indicated that, at the end of experiment Sea bass fry had reached an average live weight 18.5 and 16.2 g fish-1 for fish fed diet A and B respectively. Also the increase of protein levels in the feed to 40% caused a significant decrease in the content of indispensable amino acid (IAA) and dispensable amino acid (as %v of whole fish and muscle of wet weight). Tow methods were subsequently used to estimate the quantitative IAA requirements of Sea bass fry based on the hypothesis that (a) the dietary requirement pattern of IAA reflects the tissue pattern and (b) the rate of daily deposition in the fish can be equated with the dietary requirement as percentage of 100 g-1 diet. The quantitative IAA requirement (%) of Sea bass (Dicentrarchus labrax) diets as follow: Lysine 2.27, Methionine 1.09, Therionine 0.61, Leucine 2.4, Isoleucine 0.47, Histidine1.6, Arginine 1.39, Phenylalanine 1.43, Valine 1.22 and Tryptophane 0.42.