Glutamic Acid Supplementation Research Articles

Effects of Dietary L-glutamic acid on the Growth Performance, Gene Expression Associated with Muscle Growth-Related Gene Expression, and Intestinal Health of Juvenile Largemouth Bass (Micropterus salmoides)

The present research examined the impact of L-glutamic acid (Glu) supplementation on the growth performance, muscle composition, gene expression correlated with muscle growth, and intestinal health of largemouth bass. There were 525 fish in total, which were distributed randomly into five groups. Each group had three replicates, and each replicate consisted of 35 fish. Groups with control and experimental diets were assigned glutamic acid amounts of 0.2%, 0.4%, 0.6%, and 0.8%. The findings demonstrated that glutamic acid supplementation enhanced growth performance, feed intake (FI), and condition factor (CF), with the best value being attained at 0.4% Glu. The mean muscle fiber area was increased and the muscle fiber density was decreased in the 0.6% Glu group. The levels of total amino acids and specific amino acids, such as glutamic acid, aspartic acid, leucine, valine, alanine, and glycine, were shown to be higher in the 0.6% Glu group. In the 0.6% Glu group, the mRNA expression levels of atrogin-1, murf-1, foxo3a, and 4e-bp1 were decreased compared to the control group. Conversely, the mRNA expression levels of myf5, myog, myod, s6k1, tor, akt, and pi3k were increased in the 0.6% Glu group compared to the control group. The 0.4% Glu group had higher intestinal amylase, lipase, and protease activities and greater villus height, villus width, and muscle thickness. In summary, Glu can support largemouth bass growth, muscular development, intestinal digestion, and absorption.

Suplementação dietética de glutamina e ácido glutâmico sobre o desempenho, morfometria intestinal e características de carcaça de codornas de corte

ABSTRACT: This study evaluated the effect of dietary supplementation with glutamine and glutamic acid (Gln+Glu) on performance, intestinal morphometry, and carcass characteristics of broiler quails. Eight hundred birds were used, distributed in an entirely randomized design with 20 birds per experimental unit, and given five treatments (0.0; 0.2; 0.4; 0.6; and 0.8% Gln+Glu supplementation) with eight replicates. At 1-21 days of age, lower (P < 0.05) feed intake at 0.6 and 0.8% Gln+Glu supplementation and lower weight gain at 0.8% Gln+Glu supplementation compared to the control treatment were observed. By regression analysis, excluding the control treatment, there was an increasing linear effect (P < 0.05) for feed intake at 22 to 42 days of age. For intestinal morphometry, Gln+Glu supplementation only favored the villus development of the ileum (P < 0.05), giving it greater height at 0.2, 0.6, and 0.8% supplementation. Carcass characteristics, cuts, and edible viscera of the birds at 42 days were not affected (P > 0.05) by Gln+Glu supplementation levels. Thus, the glutamine and glutamic acid supplementation affected the performance and intestinal morphology of 21-d-old quails, decreasing feed intake and weight gain associated with the improvement of ileum morphology; conversely, performance and carcass characteristics at 42 days were not affected by amino acid supplementation.

Glutamic acid supplementation recovers the reduced performance of weanling pigs fed reduced crude protein diets.

This study was conducted to evaluate the supplementation of glutamic acid (Glu) to reduced protein diets on the performance of weanling pigs. One hundred and eighty crossbred weanling pigs ([Yorkshire × Landrace] × Duroc, 21 d old) having similar body weight (BW) of 6.45 kg were randomly allotted to 1 of 6 dietary treatments (5 pigs per pen [2 barrows and 3 gilts]; 6 pens per treatment) based on BW and sex during a 6-week trial. Dietary treatments consisted of positive control (PC) diet formulated to have 226.9, 205.6, and 188.8 g crude protein (CP) during phases 1, 2, and 3, respectively, and negative control (NC) diets with 20 g CP reduction from PC diets and addition of Glu with increasing levels, resulting in the calculated Lys-to-Glu ratios of 1:2.25, 1:2.30.1:2.35, 1:2.40, and 1:2.45, designated as NC, NC1, NC2, NC3, and NC4, respectively. The BW of pigs receiving PC diet was higher (P < 0.05) than those receiving NC diet at d 7, 21 and 42. A higher (P < 0.05) average daily gain (ADG) from d 1 to 7, 8 to 21, 22 to 42 and during the overall experiment period was observed in pigs fed PC than NC diet. Pigs fed NC diets including the graded level of Glu linearly increased (P < 0.05) BW at d 42, ADG and gain-to-feed ratio (G:F) during the overall experimental period. In addition, trends in linear increase in BW (P = 0.056) at d 7 and ADG from d 1 to 7 and d 22 to 42 (linear effect, P = 0.081, P = 0.058 respectively) were observed. A tendency in the linear increment of NH3 (P = 0.082) at d 21 and linear reduction in methyl mercaptans (P = 0.054) emission at d 42 was observed in pigs fed NC diets supplemented with graded level of Glu. In conclusion, supplementing the reduced protein diet with Glu enhanced the growth performance in weanling pigs suggesting that supplementation of Glu can compensate the reduction of 2% CP in the basal diets.

Development and Application of a Fast Gas Chromatographic Method Offer New Insights into l-theanine Production Regulation in Camellia sinensis L.

Tea is the most consumed beverage worldwide, and l-theanine in tea leaves significantly affects their flavor and market quality. We have developed and validated a fast and reliable gas chromatographic method with flame ionization detection (GC-FID) to quantify l-theanine after its extraction from Camellia sinensis (tea plant) and derivatization. The procedure was completed in 40 min, from extraction to chromatographic analysis, with a recovery rate of more than 93% and allowing a high sample throughput. The GC-FID intraday precision was within 0.57-2.28%, while the interday precision ranged from 1.57 to 13.48%. The intraday accuracy ranged from -6.84 to 5.26%, while the interday accuracy ranged from -1.08 to 3.12%. The limit of detection was 2.28 μg/mL, and the limit of quantification was 6.47 μg/mL. The GC-FID method was validated by high-performance liquid chromatography with UV detection (HPLC-UV) and was used to investigate the biosynthesis and regulation of l-theanine in tea plants. We found that plants fed with ethylamine significantly increased l-theanine concentrations in roots, while exogenous supplementation of glutamic acid, carbamide, and glutamine did not significantly affect the l-theanine level in roots. Our results also indicated that roots were not indispensable for the biosynthesis of l-theanine, which was detected in undifferentiated embryonic calluses in concentrations (g/100 g dry weight) as high as in leaves of whole plants (1.67 and 1.57%, respectively) and without any exogenous theanine precursor supplementation.

Dietary lysine restriction induces lipid accumulation in skeletal muscle through an increase in serum threonine levels in rats

We previously reported that dietary amino acid restriction induces the accumulation of triglycerides (TAG) in the liver of growing rats. However, differences in TAG accumulation in individual cell types or other tissues were not examined. In this study, we show that TAG also accumulates in the muscle and adipose tissues of rats fed a low amino acid (low-AA) diet. In addition, dietary lysine restriction (low-Lys) induces lipid accumulation in muscle and adipose tissues. In adjusting the nitrogen content to that of the control diet, we found that glutamic acid supplementation to the low-AA diet blocked lipid accumulation, but supplementation with the low-Lys diet did not, suggesting that a shortage of nitrogen caused lipids to accumulate in the skeletal muscle in the rats fed a low-AA diet. Serum amino acid measurement revealed that, in rats fed a low-Lys diet, serum lysine levels were decreased, while serum threonine levels were significantly increased compared with the control rats. When the threonine content was restricted in the low-Lys diet, TAG accumulation induced by the low-Lys diet was completely abolished in skeletal muscle. Moreover, in L6 myotubes cultured in medium containing high threonine and low lysine, fatty acid uptake was enhanced compared with that in cells cultured in control medium. These findings suggest that the increased serum threonine in rats fed a low-Lys diet resulted in lipid incorporation into skeletal muscle, leading to the formation of fatty muscle tissue. Collectively, we propose conceptual hypothesis that “amino-acid signal” based on lysine and threonine regulates lipid metabolism.

Effects of dietary L-glutamine and glutamic acid combination, and whey powder on the performance and nutrient digestion in weaned piglets fed grain-based diets.

ObjectiveThe present study aimed to evaluate the influence of including L-glutamine along with glutamic acid as a supplement in weaned piglets’ diets with and without whey powder.MethodsTwo assays were carried out. A total of 40 piglets ([Landrace×Large White]× Pietrain) weaned at 24 days of age with an initial body weight of 6.6±0.6 kg were used in the first assay, and the following parameters were evaluated: growth performance, the incidence of diarrhea, morphometry, intestinal integrity, and hepatic glycogen index. The animals were then blocked into four groups according to different diets: diet all-grain feeding (G); diet all-grain feeding with whey powder (GW); and with vs without 1% supplementation of the commercial product containing L-glutamine and glutamic acid (A or NA). Whey powder was added according to the stage of life, corresponding to 17%, 10%, and 5%, respectively, in order to meet the need for lactose. The animals were evaluated at 24 to 42 days and at 24 to 55 days of age. The nutrient digestibility for the second assay was carried out by using 24 animals with an average weight of 11.49±1.6 kg, and the same diets were tested.ResultsThe supplementation of L-glutamine + glutamic acid or the addition of whey powder in diets for weaned piglets provided (p<0.05) greater feed intake, greater weight gain and improved feed conversion in the initial period (24 to 42 days age). However, in the whole period (24 to 55 days age) only amino acid supplementation affected (p<0.05) growth performance. There was a positive interaction (p<0.05) between the type of diet and L-glutamine + glutamic acid supplementation on villus height, crypt depth and the villus:crypt ratio in the duodenum. In addition, L-glutamine + glutamic acid supplementation reduced (p<0.05) the crypt depth and improved the villus:crypt ratio in the jejunum. The inclusion of whey powder affected (p<0.05) positively the digestibility coefficients analyzed except mineral matter digestibility coeficients. The supplementation of 1% the commercial product composed of L-glutamine and glutamic acid improved (p<0.05) only the digestibility coefficient of crude protein.ConclusionThese results indicate that supplementation of 1% commercial product containing L-glutamine + glutamic acid in diets for piglets from 24 to 55 days of age, dispenses with the use of whey powder when evaluating growth performance. Amino acid supplementation alone or associated with whey powder affects (p<0.05) positively the indicators of the intestinal integrity.

Metabolomics Analysis of the Effect of Glutamic Acid on Monacolin K Synthesis in Monascus purpureus.

Monacolin K is a secondary metabolite produced by Monascus with beneficial effects on health, including the ability to lower cholesterol. We previously showed that the yield of monacolin K was significantly improved when glutamic acid was added to the fermentation broth of Monascus purpureus M1. In this study, we analyzed M. purpureus in media with and without glutamic acid supplementation using a metabolomic profiling approach to identify key metabolites and metabolic pathway differences. A total of 817 differentially expressed metabolites were identified between the two fermentation broths on day 8 of fermentation. Pathway analysis of these metabolites using the KEGG database indicated overrepresentation of the citric acid cycle; biotin metabolism; and alanine, aspartate, and glutamate metabolic pathways. Six differentially expressed metabolites were found to be related to the citric acid cycle. The effect of citric acid as an exogenous additive on the synthesis of monacolin K was examined. These results provide technical support and a theoretical basis for further studies of the metabolic regulatory mechanisms underlying the beneficial effects of monacolin K and medium optimization, as well as genetic engineering of Monascus M1 for efficient monacolin K production.

γ-Polyglutamic acid production in Corynebacterium glutamicum using sugar by one-step fermentation

γ-polyglutamic acid (γ-PGA) is widely used in food processing, cosmetic production, medicinal industry, etc. Currently, the production strains used in fermentation process are commonly glutamic acid-dependent, which results in extra cost. In this study, a de novo way of producing γ-PGA from sugars was reported. To this end, the γ-polyglutamate synthase gene cluster pgsBCA was cloned from the natural γ-PGA-producing strain Bacillus subtilis (ATCC 6051-U), and was constitutively and inducibly expressed in Corynebacterium glutamicum ATCC 13032. Only inducible expression of pgsBCA can lead to the generation of γ-PGA with a titer of 1.43 g/L from glucose, without any supplementation of glutamic acid. The production was further elevated to 1.98 g/L upon optimization of the induction conditions with the induction time at 2 h post-inoculation and the IPTG concentration of 0.8 mmol/L. Moreover, to achieve a higher titer of γ-PGA, pgsBCA was inducibly expressed in C. glutamicum F343, which shows a paramount glutamate production capacity. The final γ-PGA production reached 10.23 g/L in shake flasks and 20.08 g/L in a 5-L fermentor using glucose as the substrate. The weight-average molecular weight (Mw) of γ-PGA from recombinant strain F343 showed 34.77% higher than that produced by B. subtilis. This study provides a novel way of producing γ-PGA from sugars directly and potentiates new applications of γ-PGA in the future.

Growth performance and intestinal replacement time of 13C in newly weaned piglets supplemented with nucleotides or glutamic acid

Dietary supplementation of nucleotides (NU) and glutamic acid (GA) have been suggested for post-weaned pigs because of their potential role as performance enhancers. During this phase, both additives may become essential for newly weaned piglets acting mainly for energy generation and forming molecular basis that are important for intestinal renewal. Two experiments were conducted to evaluate the effects of dietary NU and GA on growth performance and intestinal replacement time of 13C in weaned piglets. In both experiments pigs were assigned to treatments in a 2 × 2 factorial arrangement, based on two levels of NU (0 and 0.1%) and two levels of GA (0 and 1%). The energy source of the maternal diet was based on corn (rich in 13C) whereas piglets’ post-weaning diets were based on rice (poor in 13C). In the first experiment, 84 piglets were weaned at 21 days of age and growth performance was monitored during three experimental phases (0–15d, 16–27d and 28–35d). In the second experiment, in order to assess the intestinal replacement time of 13C in weaned piglets, the differences between the natural 13C abundance in maternal diet and piglets post-weaning diets were used. At day 0 (weaning), three piglets were slaughtered and used as an initial 13C ratio for duodenum and jejunum. At days 3, 6, 9, 14, 21, 34 and 49, three more piglets by treatment were slaughtered. Exponential regression analysis from each treatment was used to determine the incorporation of 13C in small intestine tissues between supplemented and control groups (without NU and GA) to determine the 13C replacement time. In the first study, dietary NU improved G:F (p < 0.05) from day 28–35, whereas dietary GA improved G:F (p < 0.05) from day 0–15, day 28–35 and for the overall experimental period (day 0–35). In the second study, NU supplementation and the interaction of NU × GA improved the replacement time of 13C in the duodenum mucosa (21.12 ± 2.14 days and 21.85 ± 2.13 days, respectively) compared to control (24.95 days). The use of dietary NU and GA during the post-weaning period improves performance but only NU accelerates the replacement time of 13C on duodenal mucosa during the post-weaning period in pigs.

Effects of natural feeding stimulants and glutamic acid supplementation on the feed intake, growth performance and digestive enzyme activities of red sea bream ( Pagrus major ) fed fish meal‐free soy protein concentrate (SPC)‐based diet

Two experiments were conducted for red sea bream (Pagrus major). In experiment 1, the optimum level of glutamic acid and natural feeding stimulants to enhance feed intake were determined and found that glutamic acid level of 0.5% and fish meat hydrolysate (FMH) were effective. In experiment 2, fish were fed with soy protein concentrate (SPC)-based diet with synthetic feeding stimulants (Basal diet), the Basal diet with FMH (FMH diet), the FMH diet with glutamic acid (FMHG diet) and with fish meal diet (FM diet) as a control until satiation for 8 weeks. Feed intake of FMHG-fed fish was significantly higher than others (p < 0.05). Specific growth rate and the feed conversion ratio of FMHG were comparable to those of FM-fed fish (p > 0.05). Relative visceral fat ratio and crude lipid content of any SPC-based diet-fed fish tended to be lower than those of FM diet-fed fish. There were no significant differences in trypsin and lipase activities hepatopancreas among treatments. SPC can be utilized as a sole protein source in a diet for red sea bream. The lower growth performance in SPC-based diet- fed fish was not due to poor digestive enzyme secretion but could be associated with lipid utilization disorder.

Glutamic acid supplementation reduces body fat weight in finishing pigs when provided solely or in combination with arginine and it is associated with colonic propionate and butyrate concentrations.

Changes in the composition of gut microbiota have been proposed as possible causes of obesity. Our previous study showed that glutamic acid (Glu) alone or a combination of Glu and arginine (Arg) decreased backfat thickness in finishing pigs. Therefore, this study aimed to investigate the effects of dietary supplementation with Glu and/or Arg on body fat weight, composition of gut microbiota, and short-chain fatty acid concentrations in the colons of finishing pigs, and to elucidate whether body fat weight was associated with changes in the colonic microbial community and concentrations of colonic metabolites. Sixty Duroc × Large White × Landrace pigs with an average initial body weight of 77.1 ± 1.3 kg were randomly assigned to one of five treatment groups (12 pigs per group). The pigs in the control group were fed a basal diet (BD group), while those in the experimental groups were fed a basal diet supplemented with either 2.05% l-alanine (Isonitrogenous, IS group), 1.00% l-arginine (Arg group), 1.00% glutamate + 1.44% l-alanine (Glu group), or 1.00% l-arginine + 1.00% glutamate (Arg_Glu group). The results showed that dietary supplementation with alanine has no effect (P > 0.05) on body fat weight, while with both Glu and Arg + Glu decreased (P < 0.05) body fat weight and increased (P < 0.05) colonic concentrations of propionate, butyrate, and valerate relative to the BD group. Negative relationships (P < 0.05) were observed between body fat weight and colonic propionate and butyrate concentrations. Compared to the IS group, dietary supplementation with Arg or Arg + Glu decreased (P < 0.05) colonic tyramine concentration. Compared to the IS group, the butyrate concentration increased (P < 0.05) in the Arg_Glu group. Compared to the BD group, the relative colonic abundance of Actinobacteria was higher (P < 0.05) in the Arg_Glu group. The abundances of Lachnospiraceae_XPB1014_group, norank_f_Erysipelotrichaceae, and Roseburia sp. were negatively (P < 0.05) correlated with body fat weight, and the abundance of norank_f_Erysipelotrichaceae was also negatively (P < 0.05) correlated with colonic butyrate concentration. These findings suggest that decreased body fat weight in finishing pigs can be induced by Glu supplementation alone or in combination with Arg. Glu + Arg supplementation was also associated with increased colonic butyrate and propionate concentrations and increased colonic Actinobacteria abundance.

Modulation of Physiologic Parameters in Molted Isa Brown Laying-Hens by Glutamine + Glutamic Acid Supplementation

ABSTRACT Feed costs are the main limiting factors in poultry industry and alternative sources of food and/or feed supplements to optimize the bird´s life cycle and to extend their production period need to be explored. This study evaluated morphometric parameters of the small intestine and gonadotropin transcript levels in Isa Brown laying hens supplemented with glutamine + glutamic acid (Aminogut®) during a second production cycle. Molting was induced and groups of 100 hens each, were supplemented with 0, 0.8, 1.6 or 2.4% Aminogut® in their diet. At the end of the experimental period, tissue sections from duodenum, jejunum and ileum were processed by the Hematoxylin-Eosin technique and samples from hypothalamus and hypophysis were collected for RT-PCR analysis of GnRH and GnRHR transcript levels. As results, the height of the intestinal villi of the duodenum and ileum was significantly (p<0.05) higher in hens supplemented with 0.8% and 1.6% Aminogut®, while in the jejunum, no significant differences were found. Hens treated with increased doses of Aminogut® tended to increase GnRH transcripts levels, whereas those of GnRHR tended to decrease proportionally. It is concluded that supplementation of Isa Brown laying hens during a second production cycle with Aminogut® developed increased villus height in duodenum and ileum that may promote better absorption of nutrients and potentially to increase the egg production. This study shows the importance of molecular techniques such as RT-PCR to support the biological effects of nutritional compounds on morphological parameters and hen productivity.

Dietary supplementation with glutamine or glutamic acid for weanling piglets

Abstract: The objective of this work was to evaluate the effects of dietary glutamine and glutamic acid supplementation on carbon turnover (δ13C) in the muscles of piglets, on animal performance, and on feed economic feasibility. The diets consisted of: control (C), 1% glutamine (G), and 1% glutamic acid (GA). In experiment I, 111 piglets were used to assess carbon turnover in the Masseter, Psoas major, and Abdominal internal oblique muscles in terms of their isotopic composition and 13C substitution over time. In experiment II, 72 piglets were assigned randomly to blocks (eight replicates per treatment and three animals per experimental unit), in order to evaluate animal performance and feed economic feasibility. The GA diet promoted the best 13C acceleration in the studied muscles. No diet effects were observed on performance variables. The G and GA diets presented higher costs than the C diet. Although supplementation with 1% glutamine or glutamic acid accelerates carbon turnover in the studied muscles, which suggests a faster recovery during post-weaning and proves the anabolic effect of these additives, its use is not economically viable for weanling piglets.

Dietary glutamine, glutamic acid and nucleotide supplementation accelerate carbon turnover (δ13C) on stomach of weaned piglets.

The use of stable isotope analysis as a tool for characterization of carbon turnover (δ13C) in piglet's tissues by tracing its feeding system has drawn attention. Thus, this study aimed at evaluating the influence of dietary glutamine, glutamic acid and nucleotides supplementation on carbon turnover in fundic-stomach region of weaned piglets at an average age of 21 days. The diets consisted of additive-free diet – control (C); 1% glutamine (G); 1% glutamic acid (GA) and 1% nucleotides (Nu). At weaning day (day 0: baseline), 3 piglets were slaughtered to quantify the δ13C of stomach. The remaining 120 piglets were blocked by weight and sex, randomly assigned to pens with 3 piglets slaughtered per treatment at days 1, 2, 4, 5, 7, 9, 13, 20, 27 and 49 after weaning in order to verify the fundic-stomach isotopic composition by treatments. Samples were analyzed in terms of 13C/12C ratio by mass spectrometry and converted to relative isotopic enrichment values (δ13C ‰) used to plot the first order exponential curves over time using OriginPro 8.0 software. The inclusion of glutamine, glutamate and nucleotides in piglet's diets has accelerated the carbon turnover in stomach during the post-weaning period, demonstrating also that glutamate has guaranteed fastest 13C incorporation rate on fundic-stomach region and pH-lowering. Besides that, stable isotopes technique (δ13C) has proved to be an important methodology to determine the time-scales at which piglets shift among diets with different isotopic values, characterizing the trophic effects of additives and the phenotypic flexibility of stomach.

Dietary supplementation of L-glutamine and L-glutamate in broiler chicks subjected to delayed placement

This study was conducted to investigate the effect of dietary glutamine (Gln) + glutamic acid (Glu) supplementation on growth performance and physiological stress response in broiler chickens subjected to 24 h delay in placement. Equal number of day-old broiler chicks were assigned to either immediate placement or with 24 h delay in placement with no access to feed and water. Chicks from each placement group were fed either standard starter diet (control) or standard starter diet +1% AminoGut (AG; mixture of 10% Gln and 10% Glu) from 1 to 21 d. Blood and duodenal samples were collected at 21 d for analysis of serum levels of ceruloplasmin (CER), ovotransferin (OVT) and α-1 acid glycoprotein (AGP), duodenal heat shock protein (HSP) 70 expression, and villi length and crypt depth. Results showed that delayed placement for 24 h was detrimental to weight gain during the starter phase (1 to 21 d) but not thereafter. AG supplementation was not able to eliminate that reduction in weight gain and feed intake during the starter stage. However, the observed enhancement in villi length and crypt depth at d 21 resulted in improvement of FCR and weight gain during the finisher stage (22 to 42 d) and consequently the overall period (1 to 42 d). Broiler chickens supplemented with AG also showed lower mortality rate, and higher AGP, OVT, CER, and HSP 70 expression compared to their control counterparts. Based on AGP, OVT, CER, and HSP 70 expression, there is no indication that delayed placement was physiologically stressful to the broiler chickens at 21 d of age.

Ảnh hưởng của sự bổ sung acid glutamic lên tăng trọng, chất lượng quầy thịt, tỷ lệ tiêu hóa dưỡng chất và hiệu quả kinh tế của thỏ Californian tăng trưởng

This study was conducted to evaluate the effects of glutamic acid supplementation levels in diets on growth performance, carcass quality and nutrient digestibility of growing Californian rabbits. Sixty Californian rabbits at 42 days of age were arranged in a completely randomized design with 5 treatments and 3 replications. Five treatments were glutamic acid supplementation with levels of 0; 0.2; 0.4; 0.6 and 0.8 g/rabbit/day corresponding to G0, G0.2, G0.4, G0.6 and G0.8 treatments, respectively. Each experimental unit consisted of four rabbits with 2 males and 2 females. The apparent nutrient digestibility and nitrogen retention of the rabbits were measured at 70 days of age in 7 days. This experimental period lasted 10 weeks. The results showed that nutrient intakes were not significantly different (P>0.05) among treatments. Daily weight gain was improved for the rabbits supplemented glutamic acid with significantly higher value (19.8 g/rabbit/day) (P

Effect of supplementation of glutamic acid and aspartic acid in egg yolk tris and egg yolk-citrate-glucose diluents on cryopreservation of Murrah buffalo bull spermatozoa

Present study was designed to assess the effect of supplementation of glutamic acid and aspartic acid in egg yolk tris and egg yolk-citrate-glucose diluents on spermatozoa quality of Murrah buffalo bull after equilibration and thawing. Semen was collected from four Murrah buffalo bulls biweekly from each bull with the help of artificial vagina (AV) on dummy animal between 08:00 to 09:00 hours using standard protocol. A total of thirty two ejaculates were taken from four bulls. In fresh ejaculates were pooled and divided into eight equal parts. The two basic diluents used for extending semen were Egg yolk Tris (EYT) and Egg yolk-citrate glucose (EYCG). Glutamic acid and aspartic acid were supplemented in different combinations. Diluted semen was equilibrated and cryopreserved. At two stages viz. after equilibration and after 12 hours of cryopreservation (thawed samples) progressive motility, percent live and percent acrosomal damage of spermatozoa was assessed. Post thaw acrosomal damage was significantly higher ( P <0.05) in EYCG than EYT. Supplementation of aspartic acid to EYT and EYCG significantly ( P <0.05) decreased the post thaw acrosomal damage as compared to control. Supplementation of glutamic acid to EYT and EYCG significantly ( P <0.05) improved all the studied spermatozoa qualities. The addition of both aspartic and glutamic acid together did not produce any additive effect on spermatozoa quality. It can be concluded that tris buffer was a better substitute to citrate buffer and glutamic acid alone may be supplemented to semen extender to improve the spermatozoa quality after equilibration and thawing.

Effect of l‐glutamic acid supplementation on performance and nitrogen balance of broilers fed low protein diets

The aim of this study was to evaluate the effect of protein reduction and supplementation of l-glutamic acid in male broiler diets. A total of 648 chicks of the Cobb 500 strain were distributed in a completely randomized design with six treatments and six replications with eighteen birds per experimental unit. The study comprised pre-starter (1-7days), starter (8-21days), growth (22-35days) and final (36-45days) phases. The first treatment consisted of a control diet formulated according to the requirements of essential amino acids for each rearing phase. The second and third treatments had crude protein (CP) reduced by 1.8 and 3.6 percentage points (pp) in relation to the control diet respectively. In the fourth treatment, l-glutamic acid was added to provide the same glutamate level as the control diet, and in the last two treatments, the broilers were supplemented with 1 and 2pp of glutamate above that of the control diet respectively. The reduction in CP decreased the performance of broilers and the supplementation of l-glutamic acid did not influence performance when supplied in the diets with excess of glutamate. The lowest excreted nitrogen values were observed in the control diet, and treatments 2 and 3, respectively, in comparison with treatments with the use of l-glutamic acid (5 and 6). Retention efficiency of nitrogen was better in the control diet and in the treatment with a reduction of 1.8pp of CP. It was verified that the serum uric acid level decreased with the CP reduction. A reduction in CP levels of up to 21.3%, 18.8%, 18.32% and 17.57% is recommended in phases from 1 to 7, 8 to 21, 22 to 35 and at 36 to 42days, respectively, with a level of glutamate at 5.32%, 4.73%, 4.57%, 4.38%, also in these phases.

GLUTAMIC ACID IMPROVES BODY WEIGHT GAIN AND INTESTINAL MORPHOLOGY OF BROILER CHICKENS SUBMITTED TO HEAT STRESS

The objective of this study was to evaluate the effects of 1% dietary glutamic acid on the body weight, intestinal morphometry, and anti-Newcastle antibody titers of broiler chickens submitted to heat stress. One-d-old male broiler chicks (n=120) were distributed according to a 2 x 2 factorial design with two environmental temperatures (thermoneutral or heat stress) and two diets (with 0 or 1% glutamic acid). Heat stress temperature was constantly maintained (24h/day) 5 oC higher than the thermoneutral temperature. Diets supplied the nutritional requirements of broilers in the pre-starter (1 to 7d) and starter (8 to 21d) phases. Birds were vaccinated against Newcastle disease on d 7 via eye drop. On days 5, 10, 15, and 20, individual body weight was determined, serum samples were collected from five birds, and duodenum samples were collected from four birds per treatment. Serum anti-Newcastle antibody titers were determined by enzyme immunoassay and transformed into log10. Villus height, crypt depth, and villus: crypt ratio were measured in the duodenum. Data were analyzed by ANOVA. Chronic heat stress negatively affected body weight and intestinal morphometry during the pre-starter and starter phases, but had no effect on antibody titers. Dietary glutamic acid supplementation (1%) improved body weight and intestinal integrity of birds submitted to heat stress when compared with non-supplemented and heat-stressed birds.

&lt;b&gt;Glutamic acid supplementation on low protein diets for laying hens

With the objective of evaluating the effect of reducing crude protein (CP) and L-glutamic acid supplementation, Dekalb Brown laying hens with 34 weeks of age. The birds were distributed in six treatments in a completely randomized design, eight replications of eight birds. The control diet contained 17% CP. The second and third treatments had CP reduced by 1.5 and 3.0 percentage points (pp) of CP in relation to the control diet, respectively. In the fourth treatment, was added the same amount of glutamate of the control diet (2.982%), and the last two treatments was added 1 and 2 pp of glutamate in relation to control diet (3.982 and 4.98%), respectively. The treatment with 15.17% CP + 0.341% L-glutamic acid (T4) promoted higher egg production, and the control diet showed greater egg weight than others treatments. There was no significant effect on the variables on quality of eggs. The T4 presented values of excreted nitrogen similar to the others treatments, with lower concentration of uric acid than the control diet and lower cost in the production. In conclusion, it is recommended the treatment with 15.17% CP + 0.341% L-glutamic acid for Brown laying hens with 34 weeks of age.