Total Sulfur Amino Acids Research Articles

Dietary sufficiency of sulfur amino acid compounds influences plasma ascorbic acid concentrations and liver peroxidation of juvenile hybrid striped bass ( Morone chrysops × M. saxatilis)

The influence of sulfur amino acid (SAA) sufficiency in aquafeeds on tissue antioxidant status including liver ascorbic acid and lipid peroxidation has not been investigated with any fish to date. In this study, a basal diet consisting of lyophilized fish muscle and a crystalline amino acid premix without supplemental SAAs and containing 0.51% total SAAs (methionine + cystine) served as the negative control to which three graded levels of dl-methionine ( dl-met) or dl-2-hydroxy-4-methylthiobutanoic acid (MHA) were added. Quadruplicate groups of juvenile hybrid striped bass were fed each diet in a recirculating system for 6 weeks. Increases in dl-met or MHA in the diets linearly increased weight gain, survival, feed efficiency, protein efficiency ratio, protein conversion efficiency, whole-body protein and some amino acids in whole-body tissues. Because high inclusion levels of MHA (4.5–5.4 g/kg) increased intraperitoneal fat and also decreased whole-body protein and amino acids, protein conversion efficiency was used to determine relative bioavailability of MHA, which was 74.6% as effective as dl-met on an equal-weight basis. Fish fed 5.4 g MHA/kg diet had significantly higher ascorbic acid concentration in circulation than fish fed the basal diet or diets including 1.5, 3.0 g dl-met/kg or 4.5 g MHA/kg. The thiobarbituric acid reactive substances (TBARS) in liver also were negatively related to sufficiency of dietary SAA compounds. The present study is the first to provide evidence that methionine deficiency in aquafeeds may reduce/exhaust reservoirs of antioxidants such as ascorbic acid in fish tissue, which may result in irreversible oxidative stress and potentially bilateral cataracts as well as aggravate growth retardation, depressed feed efficiency and mortality.

Production Performance and Egg Quality of Hy-Line W36 Laying Hens Fed Reduced-Protein Diets at a Constant Total Sulfur Amino Acid:Lysine Ratio

Two hundred eight 20-wk-old Hy-Line W36 hens at a 5% production rate were assigned to 2 dietary treatments varying in CP content. Each treatment consisted of 13 replicates of 8 hens. Dietary CP levels of the control diet were 17.8, 19.9, 18.5, and 15.5% during the periods of 1) a 5 to 50% production rate, 2) a 50% production rate until mo 7, 3) mo 8 to 10 of the production cycle, and 4) mo 10 to 12 of the production cycle, respectively. The respective CP levels of the reduced-CP diet fed during these phases were 16.3, 18.4, 17.0, and 13.9%. The reduced-CP diets had dietary CP levels approximately 1.5 percentage units lower than their control counterparts. Dietary treatments met the minimal requirements for amino acids recommended by NRC (1994). Hen-day egg production, egg mass, and FCR were maintained well on the low-protein diet during the first 8 mo of production but tended to be impaired thereafter. In mo 10 and 11 of the laying period, egg mass was significantly ( P < 0.05) reduced and FCR was significantly ( P < 0.05) impaired on the reduced-CP diet compared with the control diet. Egg weight, eggshell thickness, eggshell breaking strength, and albumen height were not significantly affected by feeding the reduced-CP diet. In conclusion, layer performance can remain satisfactory on reduced-CP diets for short periods, but long-term feeding of reduced-CP diets may not be advisable because it will reduce performance in the late stage of production.

Effect of Feed and Air Temperature on Optimum Egg Size and Profits During Phase 1 of Bovans White Hens

Two experiments were conducted to determine the most economical protein and lysine levels to feed laying hens during Phase I (weeks 21-36) of the laying cycle in order to optimize egg weight and profits when hens were exposed to warm (25.6 C Average in Exp. 1) and cool temperatures (20.0 C average in Exp. o o 2). In both experiments, nine hundred sixty 21-weeks old hens were randomly divided into six groups of 160 hens per group and fed one of six diets. Diets were formulated based on protein and lysine. Three diets formulated on protein contained 17.00, 18.70 and 20.80% protein and 0.90, 1.02 and 1.17% lysine, respectively. Three diets formulated based on lysine contained 0.75, 0.83 and 0.92% lysine and 14.98, 16.19 and 17.34% protein, respectively. Response criteria were egg production, feed consumption and egg weight. Neither diet nor method of formulation had an effect (p>0.05) on any response criteria other than egg weight in Exp. 1 and Exp. 2. In both experiments, egg weight increased (p<0.05) as the Lysine (or protein) content increased. Using an economic analysis with egg and feed prices at the time of the study, Bovans White hens required 1,076 mg lysine, 750 mg total sulphur amino acids (TSAA), 19.1 g protein and 264 kcal ME/hen/d for optimum profits during Phase I under warm conditions and 1,100 mg Lysine, 789 mg TSAA, 20.22 g protein and 310 kcal ME/hen/d during Phase I for maximum profits when kept under cool temperatures. Because feed and egg prices vary, there can be no fixed lysine (protein) requirement for optimal profit.

Total sulfur amino acid requirement and metabolism in parenterally fed postsurgical human neonates

BackgroundExcept for tyrosine, the amino acid requirements of human neonates receiving parenteral nutrition (PN) have not been experimentally derived. ObjectivesThe objectives were to determine the total sulfur amino acid (TSAA) requirement (methionine in the absence of cysteine) of postsurgical, PN-fed human neonates by using the indicator amino acid oxidation (IAAO) technique with l-[1-13C]phenylalanine as the indicator. DesignFifteen postsurgical neonates were randomly assigned to receive 1 of 18 methionine intakes ranging from 10 to 120 mg · kg−1 · d−1, delivered in a customized, cysteine-free amino acid solution. Breath and urine samples were collected for the measurement of 13CO2 and amino acid enrichment. Blood samples were collected at baseline and after the test methionine infusion for the measurement of plasma methionine, homocysteine, cystathionine, and cysteine concentrations. ResultsBreakpoint analysis determined the mean TSAA requirements to be 47.4 (95% CI: 38.7, 56.1) and 49.0 (95% CI: 39.9, 58.0) mg · kg−1 · d−1 with the use of oxidation and F13CO2, respectively. ConclusionsThis is the first study to report the TSAA requirement of postsurgical, PN-fed human neonates. The estimated methionine requirement expressed as a proportion of the methionine content of current commercial pediatric PN solutions was 90% (range: 48–90%) of that found in the lowest methionine-containing PN solution.

Re-evaluation of total sulphur amino acid requirement and determination of replacement value of cystine for methionine in semi-purified diets of juvenile Nile tilapia,Oreochromis niloticus

Two feeding experiments were conducted to re-evaluate the total sulphur amino acid (TSAA; methionine and cystine) requirement and determine the replacement value of cystine for methionine of juvenile Nile tilapia (Oreochromis niloticus). Semi-purified diets used in both experiments contained 3510 kcal gross energy and 280 g of protein per kilogram diet from casein, gelatin and crystalline amino acids. The basal diet of the first experiment contained 3.1 g methionine and 0.4 g cystine per kilogram. l-methionine was added to the seven remaining diets at 1.0 g kg⁻¹ increment to produce methionine levels ranging from 3.1 to 10.1 g kg⁻¹ diet. Each diet was fed to four replicate groups of juvenile Nile tilapia (1.28 g mean weight) in a recirculation system for 8 weeks. Broken-line regression analysis of weight gain data indicated that the TSAA requirement of juvenile Nile tilapia was 8.5 g kg⁻¹ of the diet or 30.4 g kg⁻¹ of dietary protein. In the second experiment, TSAA level was set at 95% of the requirement value determined in the first experiment. Seven diets were made with different ratios of l-methionine and l-cystine (20 : 80, 30 : 70, 40 : 60, 50 : 50, 60 : 40, 70 : 30 and 80 : 20, based on an equimolar sulphur basis). Each diet was also fed to four replicate groups of juvenile Nile tilapia (4.14 g mean weight) in a recirculation system for 8 weeks. Regression analysis of weight gain data using broken-line model indicated that cystine (on a molar sulphur basis) could replace up to 49% of methionine requirement in semi-purified diets for juvenile Nile tilapia.

Exigências de metionina + cistina total e digestível para alevinos revertidos de tilápia do Nilo, &lt;em&gt;Oreochromis niloticus&lt;/em&gt; (L.), baseadas no conceito de proteína ideal

The nutritional requirements of total and digestible methionine for reversed fingerlings of the Nile tilapia (Perciformes, Cichlidae) were determined. During a 40-day period fingerlings, weighing 1.31 &plusmn; 0.06g each, were fed on diets with 0.89; 0.94; 0.99; 1,09; 1.19 and 1.29% of total methionine + cystine, corresponding to 0.83; 0.88; 0.93; 1.03; 1.13 and 1.23% of digestible methionine + cystine. Since diets were supplemented with increasing levels of DL-methionine, diets reached 50.61; 0.54; 56.7; 62.80; 68.90 e 75% of methionine + cystine/lysine ratio (ideal protein concept), based on digestible amino acids values. Increasing methionine + cystine levels linearly diminished survival rate. Diets with 1.10% and 1.00% levels of total and digestible sulfur amino acid respectively had the best performance results for Nile tilapia fingerlings. This corresponds to 60.11 and 60.98% of total and digestible methionine + cystine/total and digestible lysine respectively.

Exigência de metionina mais cistina, com base no conceito de proteína ideal, em rações para alevinos de tilápia-do-nilo

Com o objetivo de avaliar o efeito dos níveis de metionina + cistina digestível, com base no conceito de proteína ideal, em dietas contendo níveis subótimos de lisina digestível (1,40%), foram utilizados 396 alevinos revertidos de tilápia (Oreochromis niloticus), da linhagem tailandesa, com peso inicial de 0,86 ± 0,02 g, em delineamento inteiramente ao acaso, composto de seis tratamentos, seis repetições por tratamento e 11 peixes por unidade experimental. Os tratamentos consistiram de cinco dietas com diferentes relações metionina + cistina:lisina digestível (59,5; 63,5; 67,5; 71,5 e 75,5%) e relação treonina:lisina digestível de 80,0%; e uma dieta contendo relação metionina + cistina:lisina digestível de 75,5% e treonina:lisina digestível de 85,0%, todas isoenergéticas e isoprotéicas. Os peixes foram alimentados ad libitum, em seis refeições diárias, durante 40 dias. Avaliaram-se os parâmetros de desempenho, a composição corporal, a deposição de proteína e gordura corporais e a eficiência de retenção de nitrogênio dos peixes.O aumento da relação metionina + cistina:lisina da dieta não influenciou as variáveis avaliadas, com exceção dos teores de gordura e umidade corporais, cujos efeitos foram quadráticos e aumentaram e diminuíram, respectivamente, até a relação estimada de 67,0 e 66,7%.Contudo, a elevação da relação treonina:lisina digestível nas dietas com relações metionina + cistina:lisina digestível de 75,5% proporcionou aos peixes melhor conversão alimentar e maior eficiência de retenção de nitrogênio e de utilização da proteína e lisina para ganho.Os níveis totais ou digestíveis de aminoácidos sulfurosos de 0,91 e 0,86%, que correspondem à relação metionina + cistina:lisina total e digestível de 57,2 e 59,5%, respectivamente, foram os que proporcionaram os melhores resultados de desempenho e características de carcaça de alevinos de tilápia-do-nilo.

Use of N‐Acetyl Cysteine for the Treatment of Parenteral Nutrition–induced Liver Disease in Children Receiving Home Parenteral Nutrition

Use of <i>N</i>‐Acetyl Cysteine for the Treatment of Parenteral Nutrition–induced Liver Disease in Children Receiving Home Parenteral Nutrition

Effect of Dietary Gelatin Supplementation on the Expression of Selected Enterocyte Genes, Intestinal Development and Early Chick Performance

Day-old Ross 308 chicks were used to evaluate the effect of dietary gelatin on intestinal development and broiler chick performance. Chicks were randomly allocated to two dietary treatments. The first treatment was the control SB diet based on corn-soybean meal and second treatment was the SBG test diet that contained 2% added gelatin with the total sulfur amino acid level remaining the same as in SB. Each treatment consisted of 4 replicate pens with 14 chicks per pen. Total duration of experiment was 0-3 weeks of age. Chick performance (weight gain and feed conversion efficiency) was evaluated on day 7 and 14. To assess intestinal development, abundance of mRNA of selected enterocyte genes (alkaline phosphatase, leucine aminopeptidase and mucin) was quantitatively determined by RT-PCR on day 7. Biochemical indices including DNA concentration, protein:DNA and protein:RNA ratios were also used to assess intestinal development. Results indicated that chicks fed the SBG diet had improved feed conversion efficiency on day 7 (p<0.05) and higher body weight gain on day 21 (p<0.05) compared to chicks fed the SB diet. Furthermore, eneterocyte genes assessed were upregulated (p<0.05) in the duodenum of SBG chicks. Jejunal protein:RNA ratio was also higher for SBG chicks (p<0.05), indicating a higher rate of protein synthesis in this tissue. The non-essential amino acids provided by gelatin beyond the most limiting appear to enhance early intestinal development and chick growth.

The Lysine and Total Sulfur Amino Acid Requirements of Six- to Twelve-Kilogram Pigs

Three experiments were conducted to determine the Lys and TSAA requirement of 6- to 12-kg pigs. There were 5 replications of 5 or 6 pigs per pen (for Exp. 1, 2, and 3, n = 150, 150, and 168 with initial BW of 6.3, 6.7, and 6.4kg and final BW of 10.8, 11.7, and 11.2 kg, respectively). In Exp. 1, pigs were fed in a 13-d growth assay and treatments were: positive control (PC, 40% corn, 38% soybean meal, 10% whey, 3% fish meal, 3% fat, and 1.45% true ileal digestible (TID) Lys), and TID Lys levels of 1.1, 1.2, 1.3, 1.4, and 1.5%. The addition of Lys increased G:F (linear, P < 0.05), ADG (linear, P < 0.05; quadratic, P < 0.05), and ADFI (linear, P < 0.05; quadratic, P < 0.10). Growth performance of pigs fed the 3 highest levels of Lys was not different from those fed the PC diet. Plasma urea N (PUN) decreased linearly (P < 0.001) with the addition of Lys. Break point analysis estimated requirements of 1.43 and 1.41% for ADG and PUN, respectively. In Exp. 2, pigs were fed in a 14-d growth assay and treatments were PC (similar to that in Exp. 1; 0.88% TID TSAA), and TID TSAA levels of 0.62, 0.68, 0.74, 0.80, and 0.86% with a TID Lys level of 1.35%. There was no response of increasing TSAA from 0.62 to 0.86%. In Exp. 3, pigs were fed in a 13-d growth assay and treatments were PC (same as Exp. 2) and TID TSAA levels of 0.52, 0.58, 0.64, 0.70, and 0.76% with a TID Lys level of 1.35%. The addition of TSAA increased ADG (linear, P < 0.05; quadratic, P < 0.05) and decreased PUN (linear and quadratic, P < 0.001). However, pigs receiving the basal diet with varying levels of TSAA had lower ADG (P < 0.05) and G:F (P < 0.001) than pigs fed the PC diet. Break point analysis estimated requirements of 0.58 and 0.56% TID TSAA for ADG and PUN, respectively. Data from these experiments suggest the TID Lys requirement is 1.40% or 18.90mg TID Lys/g gain for 6- to 12-kg pigs, and the TID TSAA requirement is near 10.14mg TID TSAA/g gain, resulting in a TSAA:Lys ratio that is approximately 0.54.

A comparative evaluation of functions for partitioning nitrogen and amino acid intake between maintenance and growth in broilers

SUMMARYThe results from three types of study with broilers, namely nitrogen (N) balance, bioassays and growth experiments, provided the data used herein. Sets of data on N balance and protein accretion (bioassay studies) were used to assess the ability of the monomolecular equation to describe the relationship between (i) N balance and amino acid (AA) intake and (ii) protein accretion and AA intake. The model estimated the levels of isoleucine, lysine, valine, threonine, methionine, total sulphur AAs and tryptophan resulting in zero balance to be 58, 59, 80, 96, 23, 85 and 32 mg/kg live weight (LW)/day, respectively. These estimates show good agreement with those obtained in previous studies. For the growth experiments, four models, specifically re-parameterized for analysing energy balance data, were evaluated for their ability to determine crude protein (CP) intake at maintenance and efficiency of utilization of CP intake for producing gain. They were: a straight line, two equations representing diminishing returns behaviour (monomolecular and rectangular hyperbola) and one equation describing smooth sigmoidal behaviour with a fixed point of inflexion (Gompertz). The estimates of CP requirement for maintenance and efficiency of utilization of CP intake for producing gain varied from 5·4 to 5·9 g/kg LW/day and 0·60 to 0·76, respectively, depending on the models.

Application of the Indicator Amino Acid Oxidation Technique for the Determination of Metabolic Availability of Sulfur Amino Acids from Casein versus Soy Protein Isolate in Adult Men ,

Our objective was to determine the metabolic availability (MA) of sulfur amino acids in dietary proteins using the indicator amino acid oxidation (IAAO) technique. Five to seven men received graded levels (20, 40, 60, and 70%) of the mean total sulfur amino acid (TSAA) requirement of 13 mg · kg−1 · d−1 as a crystalline AA mixture, casein, and soy protein isolate (SPI) (40, 50, 60, and 70%), respectively. Five of these subjects received 40% of TSAA requirement from SPI supplemented with methionine to the level of 40% of requirement. These 5 subjects also repeated the level of 60% TSAA requirements from both casein and SPI to assess repeatability. The mean MA of TSAA from SPI (71.8 α 3.6%) was lower than from casein (87.4 α 3.8%, P < 0.05). Supplementation of SPI with methionine decreased the IAAO (11.5 α 0.3% administered dose) compared with unsupplemented SPI (12.8 α 0.5% administered dose, P < 0.05). IAAO was similar for repeated measurements of casein and SPI, respectively, at the 60% TSAA intake level (10.8 α 1.0 vs. 10.7 α 1.2% for casein; 12.7 α 1.3 vs. 12.9 α 2.6% for SPI). In conclusion, the IAAO technique can be used to determine the MA of AA for protein synthesis in test proteins for humans.

Supplementation of taurine and methionine to all-plant protein diets for rainbow trout ( Oncorhynchus mykiss)

Taurine has been demonstrated to be a conditionally indispensable nutrient for several carnivorous fish species. Currently, trout feeds contain reduced levels of fishmeal which had been the primary source of dietary taurine. The reduction of fishmeal in the diet, and thus dietary taurine, may limit growth. A 12-week feeding trial was conducted using a factorial treatment design with taurine supplementation (3 levels) and methionine supplementation (3 levels) as the main effects. The diets were formulated to be fishmeal free, containing only plant proteins. Taurine was supplemented at 0, 5, and 10 g/kg dry diet and methionine was supplemented at 0, 5, and 10 g/kg dry diet in a 3 × 3 factorial design. All diets were formulated to contain 43.8% crude protein from intact protein and 20% lipid. Fifteen fish with a mean initial weight of approximately 18.4 g per fish were stocked in each of 27 tanks. The unsupplemented diet had 3.6 g of taurine/kg diet and 11.5 g total sulfur amino acids (met + cys)/kg diet. Supplementation with taurine improved growth ( p = 0.096, g gain per fish), and with 5 g/kg diet an increase in feed consumption ( p = 0.095) was observed. Methionine supplementation reduced growth ( p = 0.010, g gain per fish) and feed consumption ( p = 0.055). Neither taurine nor methionine supplementation had an effect on protein retention efficiency, energy retention efficiency or feed conversion ratio. Increased methionine intakes resulted in decreased ( p = 0.009) intraperitoneal fat deposition, whereas taurine levels had no effect. Plasma GH levels were not affected by either methionine or taurine supplementation, but decreased plasma IGF-I concentrations ( p = 0.009) were associated with methionine supplementation (5 g/kg diet). In conclusion, dietary taurine inclusion does appear beneficial for trout fed all-plant protein diets, and supplementation of methionine above the requirement does not appear to spare taurine.

Replacement of Fish Meal with Soybean Meal in the Production Diets of Juvenile Red Snapper, Lutjanus campechanus

The replacement of fish meal with soybean meal in fish diets has met with varying degrees of success. Quite often, poor responses to high soybean meal diets are either due to shifts in the nutrient profile or a reduced palatability of the diet when fish meal is removed. The present research was designed to evaluate the replacement of menhaden fish meal with solvent-extracted soybean meal in practical diets containing 10% poultry by-product meal and formulated to contain 40% protein, 8% lipid, and a total sulfur amino acid content of > 3.0% of the protein. The response of red snapper (mean initial weight 10.9 g) to diets containing graded levels of fish meal (30,20, 10, 0%) as well as the response to a low fish meal diet (10%) without poultry by-product meal were evaluated over a 6-wk growth period. Significant (P± 0.05) differences in final mean weight, percent weight gain, and feed conversion were observed. Final weights (percent gain) ranged from 30.9 g (185.5%) for fish offered diets with 30% fish meal to 12.6 g (16.3%) for fish offered diets with 0% fish meal. Corresponding feed conversion efficiencies ranged from 60.1% to 7.7%. No significant differences were observed for survival between treatment means. Although there was a clear reduction in performance as the fish meal was replaced with soybean meal, the use of 10% poultry by-product meal or 10% fish meal resulted in similar performance of the fish. This is a good indication that poultry by-product meal does not have palatability problems and could be used as a substitute. The present findings suggest that replacing fish meal with high levels of soybean meal appears to reduce the palatability of the diet. While the cost reducing benefit, with respect to the replacement of fish meal, has been shown with other species, before high levels of inclusion can be efficiently utilized further research is needed to address the palatability problems observed with red snapper.

Effects of Reduced- Protein Diets at Constant Total Sulfur Amino Acids: Lysine Ratio on Pullet Development and Subsequent Laying Hen Performance

The effect of using a low protein regime in pullet development and subsequent layer performance was studied. The experiment consisted of two periods of rearing and laying. Two hundred and sixty Hy-line W36 chicks were used. In the rearing period, dietary protein level and ME content series of the control group used during starter (18-42), grower (43-63) and developer (64-119d) phases were 20, 2930, 18, 2930, and 16, 3025, respectively. Dietary protein sequence of the low protein group was 18.5, 16.5, and 14.6% during the respective periods. In the laying period lasted from week18 to week32 of age, CP content of the control and reduced-protein diets were 17.8 and 16.3%, respectively. Reduced-protein diets were kept isoenergetic with their corresponding controls in each period and phase and they balanced to keep the same total sulfur amino acid to lysine ratio as well. Results indicated that birds on reduced-protein diet during starter phase of the rearing period consumed less feed (p = 0.003) and as a result they had significantly (p = 0.012) better feed conversion ratio (FCR) compared to the control. However, dietary protein regime had no significant effect on weight gain, feed intake and FCR during grower and developer phases. In the laying period, there was no significant difference in terms of layer performance and egg quality criteria. In conclusion, reduced-CP diets can be satisfactory used for rearing pullets and laying hens up to 32 weeks of age.

Parenteral sulfur amino acid requirements in septic infants

To investigate parenteral methionine requirements of critically ill, septic infants, we conducted an investigation involving 12 infants (age 2±1 years; weight 13±2kg) using the intravenous indicator amino acid oxidation and balance technique. They received a balanced parenteral amino acid formula supplying a cysteine intake at 36 mg.kg−1.d−1. They were randomized to one of 6 different methionine intakes. Total amino acid and energy intakes were 2±0.3g.kg−1.d−1 and 59±13 kcal/kg−1.d−1. After adaptation to the assigned methionine intake for at least 24 h, an L-[1-13C] leucine tracer was given as a primed, 6h continuous, intravenous infusion. As shown in the figure, leucine balance was negative at methionine intakes of 20 and 24 mg.kg−1.d−1 (p<0.05) and total sulfur amino acid (TSAA) intakes of 56 and 60 mg.kg−1.d−1. Leucine balance was positive at methionine intakes of 28, 35, 41 and 45 mg.kg−1.d−1, and TSAA intakes of 64, 71, 77 and 81 mg.kg−1.d−1. Methionine requirement of critically ill infants appears to be at least 27 mg.kg−1.d−1, at cysteine intakes of 36 mg.kg−1.d−1. Ajinomoto 3ARP Program. NIH DK 62363.

Amino acid composition of two masticatory nuts (Cola acuminata and Garcinia kola) and a snack nut (Anacardium occidentale)

The amino acid compositions of Cola acuminata, Garcinia kola and Anacardium occidentale were evaluated by ion-exchange chromatography. Glutamic acid was the most concentrated acid in the samples. In all the amino acids determined, A. occidentale had the most concentrated acid on a pairwise basis. The total amino acids were 356.24 mg/g protein, 112.90 mg/g protein and 659.17 mg/g protein for C. acuminata, G. kola and A. occidentale, respectively. The percentage total essential amino acids were 38.39% (C. acuminata), 47.05% (G. kola) and 51.04% (A. occidentale). Also the percentage total acidic amino acids were 38.16% (C. acuminata), 30.61% (G. kola) and 30.35% (A. occidentale). The calculated isoelectric points were 2.0 (C. acuminata), 0.7 (G. kola) and 3.9 (A. occidentale), showing they can all be precipitated at acidic pH. While threonine was the limiting amino acid in A. occidentale, it was valine in both C. acuminata and G. kola. The percentage cystine (Cys) levels in the total sulphur amino acid were 44.27% (C. acuminata), 37.75% (G. kola) and 50.51% (A. occidentale). The aim of this work was to compare the amino acid profile of the samples. It is recommended that C. acuminata and G. kola consumption be avoided by ulcer patients because of their high levels of acidic amino acids. A. occidentale amino acid scores ranged from 42% to 127%, suggesting that it could be used to enhance the protein quality of cereals through food complementation.

Nutrient retention capabilities of Nile tilapia ( Oreochromis niloticus) fed bio-regenerative life support system (BLSS) waste residues

Nile tilapia were evaluated as a bio-regenerative sub-process for reducing solid waste potentially encountered in bio-regenerative life support systems. Ten juvenile Nile tilapia (mean weight = 2.05 g) were stocked into triplicate aquaria and fed one of seven experimental diets consisting of vegetable, bacterial, or food waste for a period of seven weeks. Weight gain (g), specific growth rate (mg/d), and daily consumption (g) was significantly higher ( p < 0.05) in the control group (13.80, 281.60, and 47.49, respectively) followed by the wheat bran/wheat germ group (4.25, 86.87, and 24.24). Carbon and crude lipid retention was significantly higher ( p < 0.001) in fish fed the control diet (37.99 and 68.54, respectively) followed by fish fed the wheat bran/wheat germ diet (23.19 and 63.67, respectively). Nitrogen, sulfur, and crude protein retention was significantly higher ( p < 0.001) in fish fed the wheat bran/wheat germ group (40.73, 98.65, and 40.75, respectively) followed by fish fed the control diet (23.68, 21.89, and 23.68, respectively). A general loss of minerals was observed among all groups. Strong associations were observed between crude lipid retention and sulfur retention ( r 2 = 0.94), crude lipid retention and carbon retention ( r 2 = 0.92), WG and fiber content of dietary treatments ( r 2 = 0.92), WG and carbon retention and ( r 2 = 0.88), WG and lysine content of waste residues ( r 2 = 0.86), crude protein retention and carbon retention ( r 2 = 0.84), sulfur retention and crude protein retention ( r 2 = 0.84), and total sulfur amino acid (TSAA) content of residues and WG ( r 2 = 0.81). Weaker associations existed between WG and crude lipid retention ( r 2 = 0.77), crude fiber content and carbon retention ( r 2 = 0.76), and WG and methionine content of waste residues ( r 2 = 0.75). Additional research is needed to improve the nutritional quality of fibrous residues as a means to improve tilapia’s ability to utilize these residues as a food source in bio-regenerative support systems.

Effects of Adequate or Marginal Excess of Dietary Methionine Hydroxy Analogue Free Acid on Growth Performance, Edible Meat Yields and Inflammatory Response in Female Broiler Chickens

Two experiments were conducted to determine the effects of adequate or marginal excess of dietary DL-2-hydroxy-4-(methylthio) butanoic acid (MHA) on productive performance and inflammatory response induced by E. coli lipopolysaccharide (LPS). In first experiment, day-old-female chicks (Ross strain) were provided for 48 days with four experimental diets; (1) AB diet: a diet with antibiotics (AB) and DL-methionine (DLM) to meet the total sulfur amino acid (TSAA) requirements of broiler chickens, (2) DLM diet: the first diet without AB, (3) MHA diet: a diet supplemented with MHA in place of DLM of the diet 2 to meet the TSAA requirement, (4) excess MHA diet: a diet with 1.6 folds higher than the content of MHA in the MHA diet. All diets were formulated with ingredients of plant origin. There was no difference in growth performance among the dietary treatments. Edible meat yields in chicks fed the excess MHA diet were better than that in chicks fed the DLM or MHA diet. Chicks fed the excess MHA or MHA diet showed lower plasma ceruloplasmin and alpha-1 acid glycoprotein concentration following LPS injection than those fed the DLM diet at 23 days of age. The concentrations in chicks fed the excess MHA diet were comparable to those chicks fed the AB diet. In second experiment, 7-days -old female chicks were fed either of the DLM or MHA diet for 14 days. Chicks fed the MHA showed higher excreta dry matter content than chicks fed the DLM diet. Heterophil to lymphocyte ratio in blood after LPS injection was lower in chicks fed the MHA diet than that in chicks fed the DLM diet. These results suggest that marginal excess supplementation of MHA, in place of DLM, to diet improved meat production in female broiler chicks and dietary MHA has potential to alleviate certain stress responses.

Monocarboxylate transporter 1 mediates DL-2-Hydroxy-(4-methylthio)butanoic acid transport across the apical membrane of Caco-2 cell monolayers.

The methionine hydroxy analogue DL-2-hydroxy-(4-methylthio)butanoic acid (DL-HMB) is a supplementary source of methionine commonly added to commercial animal diets to satisfy the total sulfur amino acid requirement. In this study, we characterized DL-HMB transport across the apical membrane of Caco-2 cells to identify the transport mechanism involved in the intestinal absorption of this methionine source. DL-HMB transport induced a significant decrease in intracellular pH (pH(i)) and was inhibited in the presence of the protonophore carbonyl cyanide 4-(trifluoromethoxy)-phenylhydrazone. Moreover, both Na(+) removal and 5-(N-ethyl-N-isopropyl)amiloride, an inhibitor of apical Na(+)/H(+) exchanger (NHE3), significantly reduced substrate uptake and pH(i) recovery, suggesting cooperation between H(+)-dependent DL-HMB transport and NHE3 activity. cis-Inhibition experiments with L-Ala, beta-Ala, D-Pro, betaine, or glycyl-sarcosine excluded the participation of systems proton amino acid transporter 1 and peptide transporter 1. In contrast, alpha-cyano-4-hydroxycinnamate, phloretin, L-lactate, beta-hydroxybutyrate, butyrate, and pyruvate, inhibitors and substrates of monocarboxylate transporter 1 (MCT1), significantly reduced DL-HMB uptake. Dixon plot analysis of L-lactate transport in the presence of DL-HMB revealed a competitive interaction (inhibition constant, 17.5 +/- 0.11 mmol/L), confirming the participation of system MCT1. The kinetics of DL-HMB uptake was described by a model involving passive diffusion and a single low-affinity, high-capacity transport mechanism (K(D), 1.9 nL/microg protein; K(m), 13.1 +/- 0.04 mmol/L; and V(max), 43.6 +/- 0.14 pmol/microg protein) compatible with MCT1 kinetic characteristics. In conclusion, the methionine hydroxy analogue is transported in Caco-2 cell apical membrane by a transport mechanism with functional characteristics similar to those of MCT1.