The impact of digestible lysine and sulfur amino acids on eggshell quality and egg weight control in old ISA brown hens during 62 to 74 wk.

Modifying dietary amino acids has been proposed as a strategy to improve eggshell quality by slowing down increases in egg weight (EW). This study aimed to investigate the effects of different levels of digestible lysine (dLYS) and ratios of digestible sulfur amino acids (dTSAA) to dLYS on performance and eggshell quality in ISA brown hens. A total of 288 hens were individually housed and assigned to 8 treatments, which combined 2 levels of dLYS (5.9 and 5.5 g/kg) with 4 ratios of dTSAA:dLYS (90, 85, 80, and 75) in a factorial arrangement. The study lasted 12 wk, starting at 62 wk of age. The number of eggs was not affected by the interaction between dLYS and dTSAA:dLYS or their main effect. However, the interaction between dLYS and dTSAA:dLYS showed that reducing the dTSAA:dLYS ratio from 85 to 75 when hens were fed 5.5 g/kg of dLYS resulted in a lower EW. Conversely, when hens were fed 5.9 g/kg of dLYS, no significant difference was found in EW among the different ratios of dTSAA:dLYS. Although there was no interaction between the levels of dLYS and dTSAA:dLYS on eggshell quality, reducing the dLYS level from 5.9 to 5.5 slowed down the deterioration in eggshell-breaking strength and eggshell thickness, regardless of the dTSAA:dLYS ratio. These findings suggest that adjusting dietary dLYS while maintaining the dTSAA:dLYS ratio of no less than 85 may be an effective strategy for decelerating the deterioration of eggshell quality in laying hen operations without impacting the egg production rate.

The effects of total sulfur amino acids on the intestinal health status of broilers challenged with Eimeria spp.

This study evaluated the effects of total sulfur amino acid (TSAA) levels on the performance and intestinal health of broilers challenged with Eimeria spp. A total of 432 one-day-old off-sex Cobb 500 male chicks were randomly assigned to a 3 × 2 factorial arrangement (6 replicates/12 birds), with diets and Eimeria challenge as the main factors. The diets were as follows: 70% (no methionine [Met] supplementation), 85, and 100% TSAA, supplemented with L-Met. At day 14, the challenged birds (n = 216) were orally gavaged with a pool of Eimeria acervulina, Eimeria maxima, and Eimeria tenella sporulated oocysts, and the unchallenged birds (n = 216) received water. At 6 and 12 D post inoculation (dpi), performance and intestinal health were evaluated. The challenge, regardless of diets, significantly impaired the performance, intestinal villi height, villus-to-crypt ratio, and ileal digestibility of dry matter, energy, and crude protein (CP) and modulated the tight junction protein (TJP) expression throughout the experiment. Moreover, the superoxide dismutase activity was increased, whereas the reduced glutathione (GSH)-to-oxidized glutathione (GSSG) ratio was decreased by the challenge at 6 dpi. Regardless of the challenge, the 70% TSAA diet reduced the body weight and feed intake in all phases, whereas the ileal digestibility of CP was higher in birds fed with the 70% TSAA diet than in those fed with the 100% TSAA diet at 6 dpi. No major differences were observed among the diets with regard to the intestinal histomorphology and TJP expression, and birds fed with the 100% TSAA diet had the highest GSH concentration at 12 dpi. Few interactions were observed, and the Met supplementation counteracted the negative effects of the Eimeria challenge on GSH concentration when 85 and 100% of TSAA levels were reached. Overall, the Eimeria challenge had a negative impact on growth and intestinal health. Moreover, the supplementation of L-Met until either 85 or 100% of TSAA levels were reached was enough to assure good performance and intestinal health in birds challenged or not challenged with Eimeria spp.

In vitro inhibition of Saccharomyces cerevisiae growth by Metschnikowia spp. triggered by fast removal of iron via two ways.

Simple and convenient innovative assays in vitro demonstrating Metschnikowia spp. competition with Saccharomyces cerevisiae for an essential nutrient iron are presented. The tested Metschnikowia strains possess a common genetically determined property of secreting a pulcherriminic acid which in the presence of iron (III) ions forms an insoluble red pigment pulcherrimin. Both initial accumulation in growing Metschnikowia cells and subsequent precipitation in the form of pulcherrimin in the media contribute to iron removal by functioning cells. The predominant way depends on the strain. Due to fast elimination of iron, the growth of S. cerevisiae can be inhibited by tested Metschnikowia strains at concentrations of elemental iron in the media not exceeding 12 mg kg-1. Inhibition can be regulated by additional supply of microquantities of iron onto the surface of the solid medium within 20-24 h. At relatively low concentrations of elemental iron (below 1 mg kg-1), additional supplements of iron onto the surface provide an advancement in understanding the inhibition possibilities and enable the assay control. Microscopy observations revealed that Metschnikowia chlamydospores are involved in iron removal at relatively high iron concentrations. The results may find application in development of new methodologies and strategies for biocontrol or inhibition of pathogenic microorganisms.

Cassane Diterpenoids from the Aerial Parts of Caesalpinia pulcherrima and Their Antifeedant and Insecticidal Activities against Mythimna separate and Plutella xylostella.

Ten new cassane diterpenoids, caesalpulcherrins A-J (1-10), together with 11 known analogues (11-21) were isolated from the aerial parts of Caesalpinia pulcherrima. Their structures and relative stereochemistry were elucidated by spectrometric and spectroscopic methods, including one-dimensional (1D) and two-dimensional (2D) NMR, high-resolution electrospray ionization mass spectrometry (HRESIMS), and single-crystal X-ray diffraction analysis. Compounds 1-4 represent the first examples of 2,5-dimethoxyfuranocassane diterpenoids. Results of the antifeedant activity indicated that isovouacapenol C (12) and pulcherrin N (14) exhibited remarkable antifeedant activity against Mythimna separate with EC50 values of 3.43 and 4.20 µg/cm2, respectively. Meanwhile, pulcherrimin C (13) and 12-demethyl neocaesalpin F (18) exerted significant antifeedant activity against Plutella xylostella with an EC50 data of 4.00 and 3.05 µg/cm2, respectively. Some of the compounds showed obvious toxic activity against the plant-feeding generalist insect herbivores, M. separate and P. xylostella, at 0.8 mg/mL (800 ppm). Furthermore, the structure-activity relationships of antifeedant and insecticidal activities are also discussed in the article.

Dietary sulfur amino acids affect jejunal cell proliferation and functions by affecting antioxidant capacity, Wnt/ß-catenin, and the mechanistic target of rapamycin signaling pathways in weaning piglets.

Intestinal epithelial cells undergo rapid renewal along the crypt-villus axis (CVA), which ensures intestinal functions. Weaning stress differentially effects intestinal epithelial cell metabolism and physiological states along the CVA. Sulfur amino acids (SAA) play a key role in intestinal epithelial cell functioning. This study evaluated the effects of SAA dietary supplementation on weaning pig jejunal epithelial cells along the CVA. Sixteen Duroc × Landrace × Yorkshire piglets (6.16 ± 0.22 kg BW) were weaned at 21 d of age and were blocked by BW and gender and the randomly assigned to 1 of 2 groups fed diets consisting of low (0.53%) or high (0.85%) levels of SAA for a 7-d period. All piglets were euthanized for tissue sampling on day 7 postweaning. Jejunal epithelial cells were isolated along the CVA to yield 3 "cell fractions" (upper villus, middle villus, and crypt cells). The number of proliferating cells per crypt of piglets fed the high SAA diet was lower (P < 0.05) than that for low SAA diet. High SAA diet piglets tended to have decreased (P = 0.059) sucrase activities compared low SAA diet piglets. A high SAA diet increased (P < 0.05) total antioxidant capacity, catalase, and superoxide dismutase activities compared with a low SAA diet. mRNA expression levels of claudin-1, Slc5a1, and Slc7a9 in high SAA diet piglets were lower (P < 0.05) than for low SAA diet piglets. There were no interactions between dietary SAA and cell sections along the CVA for enzyme activities and mRNA expression in any of the weaned piglets. Protein amounts and phosphorylation levels related to Wnt/ß-catenin and mechanistic targeting of rapamycin (mTOR) signaling pathways were affected by SAA in weaning piglets. These findings indicate that dietary SAA affects jejunal cell proliferation and functions in weaning piglets. There appears to be no interactions between dietary SAA and cell sections along the CVA. The effects of SAA may be partly through affecting antioxidant capacity, and Wnt/ß-catenin and mTOR signaling pathway.

The effects of dietary sulfur amino acids on growth performance, intestinal morphology, enzyme activity, and nutrient transporters in weaning piglets.

Early weaning results in intestinal dysfunction in piglets, while sulfur amino acids (SAA) are involved in improving intestinal functions. We tested a hypothesis that dietary supplementation with SAA can improve intestinal functions of weaning piglets and analyzed the effects of different dietary SAA levels on intestinal functions. A total of 80 piglets (Duroc × Landrace × Yorkshire) were weaned at 21 d of age and randomly assigned to one of the five diets that contained 0.53%, 0.63%, 0.74%, 0.85%, or 0.96% SAA, which corresponded to 70%, 85%, 100%, 115%, or 130% of the SAA:Lys ratio recommended by the National Research Council (2012). The 14 d feeding experiment involved 16 pens per diet and one piglet per pen. Eight randomly selected piglets from each treatment were euthanized for tissue sampling on day 7 and 14 post weaning. Supplementation with SAA led to a rise over time in G:F (linear, P = 0.001; quadratic, P = 0.001). Between day 0 and 14 of treatment, the jejunal crypt depth decreased (linear, P = 0.018; quadratic, P = 0.015), while that of the duodenal villus (linear, P = 0.049) and ileal villus width (linear, P = 0.029; quadratic, P = 0.034) increased. The activities of jejunal alkaline phosphatase (ALP) were quadratically increased (P = 0.040) from day 0 to 14 due to dietary SAA. Dietary SAA also elevated the activities of jejunal lactase (linear, P = 0.003; quadratic, P = 0.004), jejunal sucrase (linear, P = 0.032; quadratic, P = 0.027), and jejunal contents of glutathione (GSH) from day 0 to 7, as well as the activity of jejunal maltase (linear, P = 0.014; quadratic, P = 0.001) between day 0 and 14. During the first wk, dietary SAA linearly increased the amounts of intestinal-type fatty acid-binding protein (I-FABP) (P = 0.048) and SGLT-1 (P = 0.021) and linearly decreased the amount of GLUT2 (P = 0.029) proteins in the jejunum. The abundance of jejunal I-FABP (P = 0.044) and PEPT1 (P = 0.049) protein linearly increased from day 0 to 14 in response to this supplementation. These findings indicate that there is a dose-dependent response to dietary SAA on feed efficiency and intestinal parameters of weanling pigs.

Effects of different sulphur amino acids and dietary electrolyte balance levels on performance, jejunal morphology, and immunocompetence of broiler chicks.

As alterations of dietary electrolyte balance (DEB) can influence amino acid metabolism via changes the ions incur in their configurations, performance and immunological responses of broiler chicks might be affected. So, the current study was carried out to investigate the effects of different levels of sulphur amino acids (SAA) and DEB on performance, jejunal morphology and immunocompetence of broiler chicks. A total of 360 1-day-old male Ross 308 broiler chicks were randomly assigned to nine experimental treatments with four replicates of 10 birds each. Experimental treatments consisted of three levels of SAA (100, 110, and 120% of NRC recommendation, provided by methionine supplementation in diets with the same cysteine level) and three levels of DEB (150, 250, and 350 mEq/kg) that were fed during the entire of trial in a 3 × 3 factorial arrangement. Results showed that the relative weights of intestine and abdominal fat were decreased markedly (p < 0.001) with increasing levels of SAA and DEB respectively. Antibody titre against sheep red blood cell was neither individually nor in combination influenced by supplementation of SAA or DEB. Nevertheless, a decrease in DEB level led to a suppression in heterophile (p < 0.05) and an increase in lymphocyte counts (p = 0.06); consequently, heterophile to lymphocyte ratio was significantly decreased (p < 0.05) by decremental levels of DEB. Albumin to globulin ratio was increased after inclusion of at least 10% SAA (p < 0.001) and 150 mEq DEB/kg in the diet (p = 0.11). Although feeding high-DEB level led to a remarkable decrease in villus height (p < 0.01) and goblet cell numbers (p < 0.001), supplementing the highest level of SAA improved the height of jejunal villus. During the entire trial period, average daily feed intake (ADFI) was increased by incremental SAA levels (p < 0.05). However, inclusion of 150 mEq/kg led to not only a remarkable increase (p < 0.0001) in both ADFI and average daily weight gain (ADWG) but also to improved (p < 0.001) feed conversion ratio (FCR) both during the growing and over the entire trial periods. The present findings indicated that inclusion of low DEB decreased the heterophile to lymphocyte ratio and improved both the albumin to globulin ratio and intestinal health indices. The best growth performance was obtained with 150 mEq DEB/kg in the diet for each level of SAA.

Role of sulfur containing amino acids as an adjuvant therapy in the prevention of diabetes and its associated complications.

Amino acid supplementation is gaining acceptance as an important adjuvant therapy in the treatment of diabetes and its associated complications. Numerous studies in the literature report the impaired amino acid metabolism in diabetes and the beneficial effects of amino acids are positively correlated with the increase in plasma levels of those amino acids. Oxidative stress is known to play a major role in diabetic pathophysiology. Sulfur containing compounds are well known in the treatment of oxidative stress induced pathological disorders. Methionine, cysteine, and homocysteine are the three common sulfur containing amino acids. In addition, taurine, a sulfonic acid containing an amino group (amino sulfonic acid), is found in substantial amounts in mammalian tissues. Both experimental and clinical studies reported the modulatory effects of cysteine, N-acetyl cysteine, or compounds having cysteine moiety in the regulation of insulin secretion and plasma glucose levels. Taurine supplementation has been found to prevent the onset of diabetes mellitus in experimental models of both insulin dependent and insulin independent pathways. Recent reports suggest that the beneficial role of cysteine or taurine is mediated via their ability in reducing glycooxidation and preventing the generation of intracellular reactive intermediates. Studies with methionine or S-adinosyl methionine has been shown to increase mitochondrial DNA density in skeletal muscle, improve insulin sensitivity and prevent body weight gain. Homocysteine, on the other hand, is an emerging risk factor for cardiovascular disease and diabetic patients have higher levels of this sulfur containing amino acid. Supplementation with cysteine or taurine, however, was found to be effective in reducing plasma homocysteine levels. This review will discuss the role of sulfur containing amino acids in the regulation of hyperglycemia and in the development of its associated pathological dysfunctions.

A derivative of the CRMP2 binding compound lanthionine ketimine provides neuroprotection in a mouse model of cerebral ischemia.

Lanthionines are novel neurotrophic and neuroprotective small molecules that show promise for the treatment of neurodegenerative diseases. In particular, a recently developed, cell permeable lanthionine derivative known as LKE (lanthionine ketimine 5-ethyl ester) promotes neurite growth at low nanomolar concentrations. LKE also has neuroprotective, anti-apoptotic, and anti-inflammatory properties. Its therapeutic potential in cerebral ischemia and its mechanisms of neurotrophic action remain to be fully elucidated. Here, we hypothesize that the neuroprotective actions of LKE could result from induction or modulation of CRMP2. We found that treating primary cultured mouse neurons with LKE provided significant protection against t-butyl hydroperoxide-induced neuronal death possibly through CRMP2 upregulation. Similarly, in vivo studies showed that LKE pre and/or post-treatment protects mice against permanent distal middle cerebral artery occlusion (p-MCAO) as evidenced by lower stroke lesions and improved functional outcomes in terms of rotarod, grip strength and neurologic deficit scores in treated groups. Protein expression levels of CRMP2 were higher in brain cortices of LKE pretreated mice, suggesting that LKE's neuroprotective activity may be CRMP2 dependent. Lower activity of cleaved PARP-1 and higher activity of SIRT-1 was also observed in LKE treated group suggesting its anti-apoptotic properties. Our results suggest that LKE has potential as a therapeutic intervention in cerebral ischemia and that part of its protective mechanism may be attributed to CRMP2 mediated action and PARP-1/SIRT-1 modulation.

The effects of added sulphur amino acids, threonine and an ideal amino acid ratio on nitrogen metabolism in mature, overweight dogs.

The objectives of this study were to investigate the effects of added essential amino acids in conjunction with a dietary lysine/MJ of 0.72 on nitrogen (N) metabolism in dogs. Treatments were; a control diet, a diet that provided an ideal amino acid profile (IAA), a diet with added total sulphur amino acids (TSAA), and a diet with added TSAA and threonine (TT). Diets were fed to eight overweight, mature, female hounds using a replicated 4 x 4 Latin Square design. Food intake was similar across treatments, however, food N intake was higher (p < 0.001) for TSAA than control, IAA or TT. Nitrogen absorbed was higher (p < 0.01) for TSAA than IAA and control. Urea N excretion was greater for control than TT (p < 0.05). Urine N excretion did not differ between diets. There were no differences in digestibility or N retention of diets. There were no differences in protein turnover, synthesis, or degradation. Blood metabolites were within normal ranges and did not differ due to dietary treatment. Based on the measurements made in this study, there is no benefit for added TSAA, TT or additional EAA in diets for mature dogs formulated to provide a 0.72 g lysine/MJ ME ratio.

Extracellular cysteine (Cys)/cystine (CySS) redox regulates metabotropic glutamate receptor 5 activity.

Extracellular cysteine (Cys)/cystine (CySS) redox potential (E(h)) has been shown to regulate diverse biological processes, including enzyme catalysis, gene expression, and signaling pathways for cell proliferation and apoptosis, and is sensitive to aging, smoking, and other host factors. However, the effects of extracellular Cys/CySS redox on the nervous system remain unknown. In this study, we explored the role of extracellular Cys/CySS E(h) in metabotropic glutamate receptor 5 (mGlu5) activation to understand the mechanism of its regulation of nerve cell growth and activation. We showed that the oxidized Cys/CySS redox state (0 mV) in C6 glial cells induced a significant increase in mGlu5-mediated phosphorylation of extracellular signal-regulated kinase (ERK), blocked by an inhibitor of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (MEK), U0126, a nonpermeant alkylating agent, 4-acetamide-4'-maleimidylstilbene-2,2'-disulfonic acid (AMS), and a specific mGlu5 antagonist, 2-methyl-6-(phenylethynyl)pyridine (MPEP), respectively. ERK phosphorylation under oxidized extracellular Cys/CySS E(h) was confirmed in mGlu5-overexpressed human embryonic kidney 293 (HEK293) cells. Oxidized extracellular Cys/CySS E(h) also stimulated the generation of intracellular reactive oxygen species (ROS) involved in the phosphorylation of ERK by mGlu5. Moreover, activation of mGlu5 by oxidized extracellular Cys/CySS E(h) was found to affect expression of NF-κB and inducible nitric oxide synthase (iNOS). The results also showed that extracellular Cys/CySS E(h) involved in the activation of mGlu5 controlled cell death and cell activation in neurotoxicity. In addition, plasma Cys/CySS E(h) was found to be associated with the process of Parkinson's disease (PD) in a rotenone-induced rat model of PD together with dietary deficiency and supplementation of sulfur amino acid (SAA). The effects of extracellular Cys/CySS E(h) on SAA dietary deficiency in the rotenone-induced rat model of PD was almost blocked by MPEP pretreatment, further indicating that oxidized extracellular Cys/CySS E(h) plays a role in mGlu5 activity. Taken together, the results indicate that mGlu5 can be activated by extracellular Cys/CySS redox in nerve cells, which possibly contributes to the process of PD. These in vitro and in vivo findings may aid in the development of potential new nutritional strategies that could assist in slowing the degeneration of PD.

Dietary sulfur amino acid supplementation reduces small bowel thiol/disulfide redox state and stimulates ileal mucosal growth after massive small bowel resection in rats.

Following massive small bowel resection in animal models, the remnant intestine undergoes a dynamic growth response termed intestinal adaptation. Cell growth and proliferation are intimately linked to cellular and extracellular thiol/disulfide redox states, as determined by glutathione (GSH) and GSH disulfide (GSSG) (the major cellular redox system in tissues), and cysteine (Cys) and its disulfide cystine (CySS) (the major redox system in plasma), respectively. The study was designed to determine whether dietary supplementation with sulfur amino acids (SAA) leads to a greater reduction in thiol/disulfide redox state in plasma and small bowel and colonic mucosa and alters gut mucosal growth in an established rat model of short bowel syndrome (SBS). Adult rats underwent 80% jejunal-ileal resection (RX) or small bowel transection (surgical control) and were pair-fed either isonitrogenous, isocaloric SAA-adequate (control) or SAA-supplemented diets (218% increase vs. control diet). Plasma and gut mucosal samples were obtained after 7 d and analyzed for Cys, CySS, GSH, and GSSG concentrations by HPLC. Redox status (E(h)) of the Cys/CySS and GSH/GSSG couples were calculated using the Nernst equation. SAA supplementation led to a greater reduction in E(h) GSH/GSSG in jejunal and ileal mucosa of resected rats compared with controls. Resected SAA-supplemented rats showed increased ileal adaptation (increased full-thickness wet weight, DNA, and protein content compared with RX control-fed rats; increased mucosal crypt depth and villus height compared with all other study groups). These data suggest that SAA supplementation has a trophic effect on ileal adaptation after massive small bowel resection in rats. This finding may have translational relevance as a therapeutic strategy in human SBS.

The interactive effects of glycine, total sulfur amino acids, and lysine supplementation to corn-soybean meal diets on growth performance and serum uric acid and urea concentrations in broilers.

Four experiments were conducted to determine the interactive effects of Gly, TSAA, and Lys in corn-soybean meal diets on growth performance of broilers. All experiments were conducted with female Ross x Ross 308 or 708 broilers in brooder batteries from 0 to 18 d posthatching. Treatments had 5 to 8 replications with 5 or 6 broilers per replicate pen. Diets in all experiments were fed without or with Gly (2.32% total Gly + Ser). All diets contained 0.25% l-Lys.HCl except in experiment 1, where no crystalline Lys was added. In experiment 1, the total dietary Lys level was 1.26% with TSAA:Lys of 0.72 and 0.76. Increasing TSAA:Lys increased (P < 0.07) G:F. The main effect of Gly was not significant for ADG, ADFI, or G:F; however, G:F was increased by Gly in broilers fed 0.72 but not in those fed 0.76 TSAA:Lys (Gly x TSAA:Lys, P < 0.03). In experiment 2, the total dietary Lys level was 1.26% with TSAA:Lys of 0.51, 0.68, 0.72, and 0.76. Glycine addition did not affect ADG, ADFI, or G:F; however, increasing TSAA:Lys linearly increased (P < 0.01) ADG, ADFI, and G:F and the response was quadratic for ADG and G:F. Experiment 3 was similar to experiment 2 except the total dietary Lys level was 1.35%. Glycine addition increased (P < 0.03) G:F and decreased (P < 0.04) serum uric acid (SUA) and serum urea N concentrations. Also, increasing TSAA:Lys linearly and quadratically (P < 0.02) increased ADG, ADFI, and G:F. In experiment 4, broilers were fed 2 levels of total dietary Lys (1.26 and 1.35%), 3 levels of TSAA:Lys (0.72, 0.76, and 0.80), and without or with Gly supplementation up to a total of 2.32% Gly + Ser. Glycine addition increased ADG (P < 0.02) and G:F (P < 0.01). The increase in G:F with Gly was not the same for all TSAA:Lys (Gly x TSAA:Lys, P < 0.07). Increasing Lys increased (P < 0.01 to 0.10) ADG, ADFI, and G:F. Glycine addition increased ADG and ADFI more in broilers fed 1.35% Lys than in those fed 1.26% Lys (Lys x Gly, P < 0.09). Glycine addition increased SUA in broilers fed 1.26% Lys but decreased SUA in broilers fed 1.35% Lys (P < 0.01). Glycine addition decreased SUA in broilers fed the TSAA:Lys of 0.80 but not at the other TSAA:Lys (P < 0.08). These data indicate that Gly increased G:F and decreased SUA in diets with 1.35% Lys and excess TSAA.

Estimation of the true ileal digestible lysine and sulfur amino acid requirement and comparison of the bioefficacy of 2-hydroxy-4-(methylthio)butanoic acid and DL-methionine in eleven- to twenty-six-kilogram nursery pigs.

Three experiments were conducted to determine the true ileal digestible (TID) Lys and sulfur AA (SAA) requirement and to compare the bioefficacy of 2-hydroxy-4-(methylthio)butanoic acid (HMTBA) and dl-MET as Met sources in nursery pigs. Experiment 1 included 2 studies: 1 was 662 nursery pigs (Triumph 4 x PIC C22; initial BW 12.2 +/- 0.18 kg) allotted to 1 of 5 dietary treatments with TID Lys concentrations ranging from 1.10 to 1.50%; and the second study was 665 nursery pigs (Triumph 4 x PIC C22; initial BW 12.3 +/- 0.18 kg) allotted to 1 of 5 dietary treatments with TID SAA concentration ranging from 0.63 to 0.90%. In Exp. 2, 638 nursery pigs (Triumph 4 x PIC C22; initial BW 13.0 +/- 0.16 kg) were allotted to the same 5 SAA dietary treatments as in Exp. 1. In Exp. 3, 1,232 pigs (Triumph 4 x PIC C22; initial BW 11.0 +/- 0.30 kg) were allotted to 1 of 7 dietary treatments. The basal diet (diet 1) was supplemented with high concentrations of synthetic AA but no Met; this resulted in a dietary concentration of TID Lys of 1.30% and TID SAA of 0.50%. Diets 2 to 7 were the basal diet supplemented with 3 equimolar levels of HMTBA or dl-MET to provide TID SAA concentrations of 0.56, 0.62, and 0.68%, respectively. In Exp. 1, increasing TID Lys from 1.10 to 1.50% increased ADG (quadratic; P < 0.05) and improved G:F (linear; P < 0.002). The pooled data of Exp. 1 (SAA study) and Exp. 2 indicated that increasing TID SAA from 0.63 to 0.90% increased ADG (quadratic; P < 0.01) and improved G:F (quadratic; P < 0.01). Various methods of analyzing the growth response surface indicated that the optimal TID Lys concentration ranged from 1.28 to 1.32% for ADG (Exp. 1), and the optimal TID SAA concentration ranged from 0.73 to 0.77% for ADG and 0.80 to 0.83% for G:F (pooled Exp. 1 and 2), respectively. In Exp. 3, increasing TID SAA concentrations from 0.50 to 0.68% resulted in a linear improvement of ADG (P < 0.001), ADFI (P < 0.05), and G:F (P < 0.001). The best fit comparison of HMTBA and dl-MET was determined by the Schwartz Bayesian Information Criteria index, which indicated the average relative efficacy of HMTBA vs. dl-MET was 111%, with 95% confidence interval of 83 to 138%, within the range of TID SAA tested. Thus, the TID Lys and SAA requirements of modern lean-genotype pigs from 11- to 26-kg were greater than the 1998 NRC recommendations, and both HMTBA and dl-MET as Met sources can supply equimolar amounts of Met activity.

Effect of amino acids containing sulfur on dithiolopyrrolone antibiotic productions by Saccharothrix algeriensis NRRL B-24137.

AIMS: To study the effect of sulfur-containing amino acids (L-cysteine, L-cystine, L-methionine and DL-ethionine) on the production of dithiolopyrrolone antibiotics by Saccharothrix algeriensis NRRL B-24137. METHODS AND RESULTS: The production levels of dithiolopyrrolones were investigated by using high performance liquid chromatography in a chemically semi-synthetic medium. The production of the studied antibiotics depends upon the nature, concentration and the time of addition of these sources in the culture medium. Both cysteine and cystine favoured the specific productions of dithiolopyrrolones; iso-butyryl-pyrrothine (ISP) by cysteine, however butanoyl-pyrrothine, senecioyl-pyrrothine and tigloyl-pyrrothine by cystine, when added initially to the culture medium. The maximum specific productions of dithiolopyrrolones were observed in the presence of 5 mmol l(-1) cystine for thiolutin, 5 mmol l(-1) cysteine for ISP, and 10 mmol l(-1) cystine for others studied dithiolopyrrolones as shown in Fig. 3. The production of these antibiotics was decreased when the concentrations of cysteine and cystine were in excess. All dithiolopyrrolone specific productions were strongly inhibited by addition of methionine and ethionine, without inhibition of mycelial growth. CONCLUSIONS: Among all studied amino acids, cystine and cysteine can be used as supplements for improvement the production of dithiolopyrrolone antibiotics by S. algeriensis NRRL B-24137. SIGNIFICANCE AND IMPACT OF THE STUDY: Dithiolopyrrolone antibiotics have many important applications for employing them as medicaments, particularly in the treatment of human and animal cancers. In the present work, the influence of containing-sulfur amino acids on dithiolopyrrolone antibiotic productions was studied. The obtained results can be employed for the optimization of the culture medium for the dithiolopyrrolone productions in higher quantities.

The effect of graded levels of dietary casein, with or without methionine supplementation, on glutathione concentration in unstressed and endotoxin-treated rats.

Glutathione (GSH) concentration was measured in rats fed either graded levels of dietary casein (experiment 1; 180 g, 120 g, 80 g, or 60 g protein/kg diet) or graded levels of dietary casein, supplemented with methionine to equalize dietary sulfur amino acid content to that seen in an 180 g/kg casein diet supplemented with 0.3 g L-methionine/kg diet (experiment 2; 180 g protein +0.3 g L-methionine, 80 g protein +6.70 g L-methionine, or 60 g protein +7.45 g L-methionine/kg diet). Rats were given an inflammatory challenge by intraperitoneal injection of endotoxin (lipopolysaccharide from Escherichia coli), and were compared with ad libitum and pair-fed controls. Glutathione concentration in various organs (liver, lung, spleen, and thymus) decreased in animals fed the low-protein diets (80 g or 60 g/kg diet). Addition of the sulfur amino acid, methionine, to the low-protein diets restored glutathione concentrations in animals fed ad libitum and prevented the fall in GSH concentration, which occurred in lung, spleen, and thymus in response to the endotoxin. Despite the similarity in the amount of sulfur amino acid consumed between the groups fed the 180 g protein +0.3 g L-methionine and the 60 g protein +7.45 g L-methionine/kg diet, in experiment 2, hepatic GSH concentration significantly increased in the latter group, in animals fed ad libitum and in the endotoxin-treated animals, but not in the pair-fed controls.

Use of bioimpedance spectroscopy to estimate body water distribution in rats fed high dietary sulfur amino acids.

The effect of dietary sulfur amino acids on bioelectric properties was studied in rats by using bioimpedance spectroscopy. Weanling rats were assigned to one of 12 groups in a factorially arranged experiment with dietary variables of supplemental sulfur amino acid (none, 10 g DL-methionine/kg or 10 g DL-homocystine/kg), pyridoxine hydrochloride (0 or 7.5 mg/kg) and nickel (0 or 1 mg/kg). After 9 wk of feeding, 20-h urine specimens were collected from food-deprived rats for measurements of creatinine, and then bioimpedance was measured with multifrequency (Hydra ECF/ICF 4200) and single-frequency (RJL Systems model 101) analyzers. Urinary creatinine excretion was measured by intracellular water (ICW), total body solid and urinary volume (R2 = 0.675). Extracellular water (ECW) did not add significantly to the model. Rats fed methionine had significantly lower total body water, ICW and ECW than rats fed no supplemental sulfur amino acid. Rats fed homocystine had significantly lower ECW and a significantly higher ratio of ICW to ECW. Rats fed methionine or homocystine had significantly lower capacitance corrected for body length and ICW than those fed no supplemental sulfur amino acids. These results suggest that dietary homocystine changes the distribution of body water and that sulfur amino acids can affect membrane porosity and/or membrane thickness.

Effects of dietary sulfur-containing amino acids on oxidative damage in rat liver caused by N-nitrosodimethylamine administration.

Effects of dietary protein and S-containing amino acids on oxidative damage were investigated in rat liver. After feeding rats for 3 weeks from weaning, lower GSH levels and higher metallothionein (MT) levels were found in the liver of rats fed on a 10% soyabean-protein-isolate (SPI)-based diet than those fed on a 10% casein-based diet. After injection of N-nitrosodimethylamine (NDMA) at 20 mg/kg body weight, increases in lipid peroxide, determined as thiobarbituric-acid reactive substances (TBARS), and gamma-glutamyltransferase (GGT) activity in the liver were observed in the 10% SPI diet group. By supplementing the 10% SPI diet with 0.3% cystine or methionine, GSH levels were increased, while MT levels were decreased, and elevation in TBARS levels after NDMA injection was diminished. On the other hand, increase in GGT activity could be prevented only by methionine supplement. On a 20% SPI or casein diet, TBARS concentration and GGT activity were not altered after NDMA injection with concomitant increase in GSH levels and decrease in MT levels. These results indicate that sufficient amounts of methionine and cystine in a diet are important to protect the liver from oxidative damage after NDMA administration, and GSH plays a primary role in the cellular protective function when compared with MT.

Influence of the dietary ratio between sulphur containing amino acids and lysine on performance of growing-finishing pigs fed diets with various lysine concentrations.

This study was conducted to determine the optimal ratio between sulphur containing amino acids and lysine in diets for growing-finishing pigs. Therefore, a total of five trials was carried out in which growing-finishing pigs (live weight range between 53 and 105 kg) were fed diets with various concentrations of lysine (0.62, 0.70 and 0.78%) and various ratios between sulphur containing amino acids to lysine. The diets contained 12.9 MJ ME per kg and 13.5% CP; the ratio between sulphur containing amino acids to lysine was adjusted by individual supplementation of the diets with DL-methionine. Increasing dietary levels of lysine from 0.62 to 0.78% continuously increased daily body weight gains and improved feed conversion efficiency as well as carcass characteristics. There was no significant interaction between the dietary lysine supply and the ratio between sulphur containing amino acids to lysine on animal performance parameters. This means that the effect of the ratio of sulphur containing amino acids to lysine was similar for various dietary lysine concentrations. The optimum ratio between sulphur containing amino acids to lysine according to quadratic regression analysis was 0.60, for both, growth and feed conversion. Reducing the ratio between sulphur containing amino acids to lysine from 0.59 to 0.53 and 0.47 reduced body weight by 3 and 12%, resp., and elevated the feed conversion ratio by 2 and 12%, resp. An increase of the ratio between sulphur containing amino acids to lysine from 0.59 to 0.65 failed to increase the animal performance. In contrast to animal performance parameters, optimum carcass characteristics (eye muscle area, fat area above eye muscle, meat-fat ratio and lean percentage) were achieved already at a ratio of sulphur containing amino acids to lysine of 0.53.

Hepatic betaine-homocysteine methyltransferase activity in the chicken is influenced by dietary intake of sulfur amino acids, choline and betaine.

There is much interest in the metabolism of homocysteine, because elevated plasma homocysteine [hyperhomocyst(e)inemia] is an independent risk factor for the development of cardiovascular disease. Four chick assays were conducted to determine the effects of varying dietary sulfur amino acids, choline and betaine on the activity of hepatic betaine-homocysteine methyltransferase (BHMT), an enzyme likely to be important in modulating plasma homocysteine. In Experiment 1, chicks were fed a purified crystalline amino acid diet containing adequate sulfur amino acids and choline. Excess dietary methionine, or the combination of excess cystine with choline or betaine, caused a small increase (P < 0.05) in BHMT activity. In Experiment 2, use of a methionine-deficient purified diet resulted in a threefold increase (P < 0.05) in BHMT activity, and addition of choline or betaine further increased (P < 0.05) BHMT activity. In Experiment 3, use of a methionine-deficient corn-peanut meal diet increased BHMT (P < 0.05) relative to that of chicks supplemented with adequate methionine, and addition of surfeit choline to the methionine-deficient basal diet caused a further increase (P < 0.05). In Experiment 4, addition of both surfeit choline and surfeit betaine to the methionine-deficient corn-peanut meal diet caused an increase (P < 0.05) in BHMT activity relative to that observed in chicks fed the methionine-deficient basal diet. These assays show that large increases in BHMT activity can be produced under methionine-deficient conditions, especially in the presence of excess choline or betaine.