DL-methionine Research Articles

PSVII-16 Dietary creatine and sulfur amino acids for finishing gilts

Abstract The objective of this study was to evaluate the effects of dietary creatine and SID methionine+cysteine (Met+Cys) levels on the performance, blood parameters and gene expression of the creatine transporter (SLC6A8) in finishing gilts. Forty gilts, averaging 75.26 ± 0.87 kg of initial weight, were distributed in a randomized blocks design in a 2x2 factorial scheme, consisting of two creatine monohydrate (CMH) supplementation levels (0.00 and 0.10%) and two levels of SID Met+Cys (0.40 and 0.44%, considering 0.44% as the requirement), with 10 replicates. DL methionine was used to ensure the dietary SID Met+Cys levels. Upon reaching a mean weight of 100± 5.85, blood was collected for the determination of urea, creatinine, lactate, glucose and homocysteine plasma concentrations. Afterwards, the gilts were slaughtered for the collection of Longissimus dorsi muscle samples, for further determination of the gene expression of the creatine transporter (SLC6A8). No interactions (P > 0.05) we observed between the CMH and SID Met+Cys on the performance and gene expression of the SLC6A8 transporter, and also were not affected (P > 0.05) by the dietary levels of CMH or SID Met+Cys, individually. However, there was an interaction (P = 0.03) between SID Met+Cys and CMH levels on the plasma creatinine concentration, showing a lower (P = 0.018) concentration (6.40 mg/dL) supplementing 0.10% CMH than not supplementing (8.96 mg/dL), only at 0.44% of SID Met+Cys. There were no interactions (P > 0.05) between SID Met+Cys and CMH on the other blood parameters, and also no individual effects were observed for the studied factors. It is concluded that supplementing 0.10% CMH reduced plasma creatinine concentration only at conventionally dietary SID Met+Cys level (0.44%), not affecting other blood parameters, growth performance and the gene expression of the creatine transporter SLC6A8 of finishing gilts.

DL – methionine can be replaced partially by phyto-additive without affecting growth performance, fat metabolism, and serum biochemistry in broilers

SUMMARY The aim was to evaluate the partial replacement of synthetic DL-Methionine (DL-Met) by Herbal Methionine (H-Met) compared to DL-Met and L-Methionine (L-Met), and the effects on growth performance, fat metabolism, and serum biochemistry in broilers. A total of 600 1-d-old male Cobb500™ chicks (Cobb x Cobb) were distributed in a completely randomized design, five dietary treatments, six replicates of 20 birds each. Liquid L-Met was provided through carboys connected to the water line. Two positive control (PC) treatments were used, either connected to the regular water line (PC1) or to carboys (PC2). The treatments were: Negative control (NC—no Met supplementation); PC1 and 2 (100% DL-Met); 60% DL-Met + 40% H-Met through feed (TH-Met); and 50% DL-Met + 50% L-Met through water (TL-Met). At 10, 22, and 42 d body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR) were determined. At day 21, serum and liver samples were used to evaluate serum biochemistry and the expression of genes related to fat metabolism, respectively. At 42 d, abdominal fat was weighed from 3 birds/replicate. In general, birds fed NC showed lower BWG, FI, higher FCR, and tended to have higher fat pad compared to the other treatments (P 0.05). For serum biochemistry, Aspartate amino transferase (AST) level was higher in birds fed NC and TH-Met than in PC2 and TL-Met (P

Growth Performance of Broilers as Influenced by Different Levels and Sources of Methionine Plus Cysteine

Simple SummaryThe current work evaluated the utilization of different sources of methionine either from DL-methionine (DL-Met) or L-methionine (L-Met) using different concentrations of dietary methionine plus cystine (Met + Cyst) in broiler chickens. Results showed that a better edible meat yield could be obtained by supplementing Met + Cyst at the rate of 80% of the digestible lysine.The objective of this work was to evaluate the utilization of methionine from DL-methionine (DL-Met) and L-methionine (L-Met) with different levels of dietary methionine plus cystine (Met + Cyst) in broilers. The experimental diets were formulated by using three levels of Met + Cyst, i.e., 74%, 77% and 80% of digestible lysine. Met + Cyst was provided either from DL-Met or L-Met. A total of 450 day-old broilers were divided into six groups (five replicates of 15 birds each) in a 3 × 2 factorial arrangement under completely randomized design. Weight gain (WG), feed intake (FI) and feed conversion ratio (FCR) was determined. At the end of the experiment (35 days), two birds from each replicate were slaughtered to determine carcass characteristics and serum homocysteine. Results indicate that the combined effect of L-Met and DL-Met significantly affected (p < 0.05) the WG in the starter period and FI in the finisher period. Neither source nor level of methionine influenced (p > 0.05) the FI, WG and FCR of broilers during the starter, finisher or overall phase of growth. The interaction between sources and levels of methionine did not influence (p > 0.05) the feed intake, weight gain and FCR during the overall phase of growth. Source of methionine had no (p > 0.05) effect on carcass characteristics. Methionine levels had a significant effect (p < 0.05) on carcass weight, chest weight and thigh weight. The interaction between sources and levels of methionine had a significant (p < 0.05) effect on the liver weight. The sources of methionine had significant (p < 0.05) effects on the liver and heart weight, while methionine levels significantly influenced (p < 0.05) the liver and gizzard weight. Finally, it was concluded that if DL-Met and L-Met are included in feed at a standard level, they are equally effective as a source of methionine for broilers.

Supplemental methionine exerted chemical form-dependent effects on antioxidant status, inflammation-related gene expression, and fatty acid profiles of broiler chicks raised at high ambient temperature1.

This study was to explore metabolic effects of two forms and concentrations of supplemental methionine in grower and finisher diets for broiler chickens raised at high temperature. Male Cornish cockerel chicks (total = 360, day-old) were divided into four groups (10 pens/treatment, 9 chicks/pen) and fed with 100% or 130% required methionine in the diets as DL-methionine (DL-MET) or 2-hydroxy-4-(methylthio)butanoate (HMTBA). The room was maintained at 4 to 13 °C above the suggested thermoneutral temperature. The higher concentration of both DL-MET and HMTBA enhanced (P < 0.05) hepatic GSH concentrations of the growers and plasma ferric reducing ability of the finishers. The DL-MET-fed growers had greater (P < 0.05%) muscle GSH and hepatic unsaturated fatty acid concentrations than those fed HMTBA. Expression of inflammation-related genes in the liver of finishers was affected (P < 0.05) by interaction effects of the methionine form and concentration. In conclusion, effects of the extra methionine supplementation on the high ambient temperature-related metabolic responses of broilers varied with their age and(or) tissue and the methionine form.

The immune response of young turkeys to haemorrhagic enteritis virus infection at different levels and sources of methionine in the diet

BackgroundHaemorrhagic enteritis (HE) of turkeys was first described in 1937 in the USA, while in Poland it was first diagnosed in 1987. Polish haemorrhagic enteritis virus (HEV) isolates are usually low pathogenic and trigger a subclinical disease. Unfortunately, even the low- pathogenic HEV strains cause severe immunosuppression leading to secondary bacterial infections and huge economic losses. The objective of this study was to evaluate if the influence of Met on HEV infected turkeys immune response can be differentiated by both its level and source. Met is one of the amino acids that not only play a nutritional role but also participate in and regulate key metabolic pathways and immune response. In our study, the birds were assigned to 4 dietary treatments which differed in Met levels (0.55 and 0.78% in weeks 1–4 of age and 0.45 and 0.65% in weeks 5–8 of age, respectively) and sources (DL-methionine (DLM) or DL-methionine hydroxy analogue (MHA)).ResultsThe HEV added the percentage of CD4+ cells and decreased the percentage of IgM+ cells in the blood, spleen and caecal tonsils (CTs) of turkeys. In addition, it increased the percentage of CD4+CD25+ cells in blood, and interleukin-6 (IL-6) level in plasma. The higher dose of Met led to a significant decrease in the percentages of CD4+, CD8+ and CD4+IL-6+ cell subpopulations in the blood of HEV-infected and uninfected turkeys and to an increase in the percentage of IgM+ B cells in CTs. Turkeys administered feeds with an increased Met content displayed a decrease in plasma IL-6 levels and an increase in plasma IgA levels.ConclusionsThe results of this study indicate that HEV infection impairs the immune function in turkeys. Met content in the feed has a moderate effect on the immune response in HEV-infected turkeys. The source of this amino acid appears not be as important as its dose, because value of the analysed parameters did not differ significantly between turkeys receiving feeds with DLM or MHA. In the uninfected turkeys, the higher by 40% (than recommended by NRC) level of Met in the feeds had a positive effect on humoral immunity parameters.

Therapeutic Effects of Parenteral Vitamin C (Ascorbic Acid) on Struvite Crystalluria in Domestic Male Cats

BACKGROUND: Struvite crystals (Magnesium Ammonium Phosphate) are one of the most common causes of urolith formation in cats. Presence of these crystals in urea leads to urinary obstruction and idiopathic cystitis. The prevalence of urinary crystals has increased in recent years, thus there has been a growing interest in development of noninvasive, fast responsive therapies. Vitamin C is a safe compound with antioxidant properties. This vitamin is known as urine acidifier as well. Since struvite crystals are more soluble in acidic pH, it could be expected that vitamin C application could improve crystals dissolution as well as their disposal. It could also prevent other complications. OBJECTIVES: This study was designed to analyze the effects of vitamin C in reducing the rate and intensity of struvite crystals with current long term therapies such as diet alteration, acidifier’s applications and diuretics. METHODS: Ten male domestic cats with clinical signs of lower urinary tract disease were selected. Struvite crystalluria was confirmed by urine analysis and ultrasonography. Cats were divided to treatment and control groups each containing 5 cats. Both groups were treated by conventional therapies for two weeks, however, during the 1st week the treatment group received injectable vitamin C (100 mg/kg, every 24h, SC) and the control group received oral DL Methionine (200mg/cat, every 8h), in addition to conventional therapies. Urine was collected at days 0, 7 and 14 and its pH, specific gravity and number of crystals were calculated. Presence of floating echogenic foci was evaluated using ultrasound. RESULTS: Significant decrease in struvite crystalluria was observed in both groups. However, in group treated by vitamin C this decrease was faster and more effective. In addition, in case of obstruction, vitamin C showed better therapeutic effects. CONCLUSIONS: According to these results, vitamin C injection could be a therapeutic approach in treatment of urinary tract obstructions where fast response is needed to avoid further complications. Oral methionine seems to be a suitable choice for prophylaxis in patients with moderated signs and relatively high urine pH or continuing therapy to prevent recurrence of disease.

Glucose metabolism is differentially altered by choline and methionine in bovine neonatal hepatocytes.

Choline and methionine serve essential roles in the liver that may interact with glucose metabolism. Our objectives were to quantify glucose export, cellular glycogen, and expression of genes controlling oxidation and gluconeogenesis in primary bovine neonatal hepatocytes exposed to increasing concentrations of choline chloride (CC) and D,L-methionine (DLM) with or without fatty acids (FA). Primary hepatocytes isolated from 3 Holstein calves were maintained as monolayer cultures for 24 h before treatment with CC (61, 128, 2028, 4528 μmol/L) and DLM (16, 30, 100, 300 μmol/L) with or without a 1 mmol/L FA cocktail in a factorial design. After 24 h, media was harvested to quantify glucose, β-hydroxybutyrate (BHB), and cells harvested to quantify glycogen, DNA, and gene expression. No interactions between CC and DLM were detected. The potential two-way interaction between CC or DLM and FA was partitioned into three contrasts when P ≤ 0.20: linear without FA, linear with FA, difference of slope. Fatty acids did not affect glucose or cellular glycogen but increased pyruvate carboxylase (PC), cytosolic and mitochondrial phosphoenolpyruvate carboxykinase (PEPCKc, PEPCKm), and glucose-6-phosphatase (G6PC) expression. Increasing CC decreased glucose but increased cellular glycogen. Expression of PC and PEPCKc was increased by CC during FA treatment. Increasing DLM did not affect metabolites or PC expression, although PEPCKc was marginally decreased. Methionine did not affect G6PC, while CC had a marginal quadratic effect on G6PC. Oxidative and gluconeogenic enzymes appear to respond to FA in primary bovine neonatal hepatocytes. Increased PC and PEPCKc by CC during FA treatment suggest increased gluconeogenic capacity. Changes in G6PC may have shifted glucose-6-phosphate towards cellular glycogen; however, subsequent examination of G6PC protein is needed. Unaltered PC and marginally decreased PEPCKc suggest increased oxidative capacity with DLM, although BHB export was unaltered. The differential regulation supports unique effects of CC and DLM within bovine hepatocytes.

Assessment of Meat Quality and Shelf Life from Broilers Fed with Different Sources and Concentrations of Methionine

A trial with different concentrations of DL-methionine (DLM) and DL-2-hydroxy-4-methylthiobutanoic acid (DL-HMTBA) in broiler feed was performed to investigate their effect on the meat quality parameters and the shelf life of breast fillet. In total, fillets from 210 male broiler chickens (Ross 308) were tested in seven groups with 30 animals each. Three different concentrations (0.04, 0.12, and 0.32%; on an equimolar basis) of either DLM or DL-HMTBA were added to a basal diet, summing up to seven treatment groups. After slaughter, fillets were packed aerobically and stored at 4°C. The investigated parameters comprised measurements of microbial as well as physicochemical parameters, such as pH, drip loss, cooking loss, and color measurements. Additionally, sensory investigations were conducted and shelf life was calculated. Mean pH values were between 6.1 and 6.4. Drip loss values were low, with mean values below 0.4%. The cooking loss ranged between 22% and 28% on average. The fillets showed a normal initial microbial quality (2.5 log10 cfu/g) and spoilage process with microbial counts of 8.5 log10 cfu/g at the end of storage. The study revealed a significant influence of methionine supplementation on the quality of broiler breast meat in comparison with the basal group. Methionine supplementation led to higher pH values and a higher water binding. Higher concentrations of methionine had a positive influence on the water-holding capacity by lowering the cooking loss. The L∗ value showed a significant negative correlation to the methionine concentration supplemented. No differences in physicochemical as well as sensory parameters could be detected between both methionine sources. The fillets showed a normal sensory spoilage process and a shelf life of 6 d. White striping was positively correlated to fillet weight as well as color values and significantly affected the Purchase Decision, the sensory investigation, and thus the shelf life of the samples.

The effect of different dietary levels of DL-methionine and DL-hydroxy analogue on the antioxidant status of young turkeys infected with the haemorrhagic enteritis virus

BackgroundThe results of experiments involving broiler chickens and turkeys indicate that increased dietary methionine (Met) levels may improve the antioxidant protection of tissues in fast-growing birds. This is an important consideration since viral infections induce oxidative stress. The aim of this study was to verify the hypothesis that turkey diets with increased Met content can suppress oxidation processes induced by infection caused by the haemorrhagic enteritis virus (HEV), and that the noted effect is determined by the chemical form of this amino acid: DL-methionine (DLM) or DL-hydroxy analogue of Met (MHA).ResultsDietary Met content above 40% higher than the level recommended by the NRC (1994) intensified lipid peroxidation in the small intestine, leading to an increase in malondialdehyde (MDA) and lipid peroxide (LOOH) levels, but it also stimulated antioxidant mechanisms in the blood and liver of turkeys infected with HEV. In comparison with DLM, MHA contributed to more severe symptoms of oxidative stress, such as elevated MDA levels in the intestines, and a decrease in glutathione peroxidase (GPx) activity and ferric-reducing ability of plasma (FRAP).ConclusionsIn HEV-infected turkeys, diets with increased Met content did not exert a clear antioxidant effect, which was noted in uninfected birds. The prooxidant activity of Met observed in the small intestinal wall was suppressed in the blood and liver of turkeys, most likely due to intensified synthesis of uric acid and glutathione. In comparison with MHA, DLM had a more beneficial influence on the analysed parameters of the redox status in the small intestine, blood and liver of turkeys.

Methionine deficiency decreases hepatic lipid exportation and induces liver lipid accumulation in broilers

The objective of the study was to investigate the effects of deficiency or high level addition of methionine (Met) in diet on homocysteine (Hcy) metabolism and hepatic lipid metabolism in broiler. A completely random design was used with 3 dietary treatments with the addition of Met from DL-methionine (DLM) at 0%, 0.22%, and 0.32% in a basal diet. The analyzed dietary Met was 0.271%, 0.485%, and 0.584% respectively for the Met-deficient, sufficient, and excessive diet. A total of 360 one-day-old male Ross 308 broiler chicks were randomly assigned to the treatments. The trial was last for 21 d. Compared to the Met-sufficient diet, the Met-deficient diet significantly resulted the decrease of 1 to 21 d growth performance and the increase of liver ether extract (EE). Compared to the Met-sufficient group, the expression of lipid transport gene apolipoprotein B (APOB) in both Met-deficient and Met-excessive group was decreased (P < 0.05). However, compared to the Met-sufficient group, a decreased of serum low-density lipoprotein cholesterol (LDLC) was only shown in birds fed a Met-deficient diet (P < 0.05). Although the plasma Hcy content was decreased, the expression of Cystathionine β-synthase (CβS) and hepatic inflammatory cytokines included interleukin-1 (IL-1) and interleukin-8 (IL-8) was significantly decreased in birds fed the Met-deficient diet when compared to those in Met-sufficient group (P < 0.05). When compared to the Met-sufficient group, the broilers in high dietary Met group had increased levels of catabolic enzyme genes expression especially acyl-coenzyme A oxidase 1 (ACOX1) and carbohydrate response element-binding protein (CHREBP) (P < 0.05), and a decreased content of liver EE. In conclusion, dietary Met deficiency decreased the hepatic lipid export and subsequently increased the hepatic lipid accumulation. High dietary Met addition increased the hepatic lipid catabolism and subsequently decreased the liver lipid accumulation.

In-situ single-step electrochemical AgO modified graphite pencil electrode for trace determination of DL-methionine in human serum sample

A proficient and cost-effective electrochemical method for the determination of DL-methionine (DLM) has been successfully developed. The in-situ single-step AgO modification of the graphite pencil electrode (GPE) was characterized by Field Emission Scanning Electron Microscope (FE-SEM), Energy Dispersed X-ray (EDX), X-ray Photoelectron Spectroscopy (XPS), and cyclic voltammetry. The electrocatalytic activity of the silver ions in 0.10 M NaOH (pH 13.7 ± 0.2) initiated the oxidation reaction of DLM on the GPE surface via Ag2+ metal-induced reaction of hydroxyl radical (OH·). Electrode linearity dependence obtained is given as iμA= 68.1CDLM + 2.99 for a linear range concentration of 60 μM - 500 μM with a correlation coefficient (R2) of 0.986 and limit of detection of 0.42 μM. Effects of potential interferences such as ascorbic acid (AA), l-alanine (Aln) and cysteine was found to be insignificant. The developed detection method was found to be suitable for both voltammetric and amperometric techniques for the development of non enzymatic sensor of DLM, and its real life application in human serum sample by standard addition method with a correlation coefficient (R2) of 0.999.

Effects of L‐methionine on performance, gut morphology and antioxidant status in gut and liver of piglets in relation to DL‐methionine

This study investigated the hypothesis that dietary supplementation of L-methionine (L-Met) in weaned piglets in relation to DL-methionine (DL-Met) results in a higher antioxidant status and lower need for antioxidant enzyme activation in intestinal epithelium and body tissues, and improves gut morphology and gut barrier function as well as performance. A total of 99 early-weaned 21-day old piglets were allotted to six groups and fed a semi-synthetic wheat-barley-based basal diet supplemented with 0.067%, 0.107% and 0.147% of either DL-Met (MetAmino; Evonik, Hanau, Germany) or L-Met (L-Met100; CJ Europe, Schwalbach am Taunus, Germany) to reach dietary Met concentrations of 0.16%, 0.20% and 0.24%, of which the latter met the requirements for maintenance and growth based on a pre-experiment. Feed intake and body weights were recorded weekly, and samples of plasma, liver and duodenum and jejunum mucosa were collected after 3weeks at slaughter. Plasma concentrations of L-Met were similar, and those of D-Met and total Met were higher in piglets fed DL-Met in relation to those fed L-Met. Feed intake, daily gains and feed:gain ratio, and the relative bio-efficacy based on gains and feed:gain ratio were similar for both groups. Likewise, villi length, crypt depth, the villi length:crypt depth ratio in duodenum and jejunum and gene expression of tight junction proteins in the jejunum did not differ. Concentrations of antioxidants like glutathione and tocopherol, the total antioxidant capacity, the mRNA abundance or activity of antioxidant enzymes like superoxide dismutase and glutathione peroxidase, concentrations of thiobarbituric acid reactive substances, markers for oxidative damage of lipids and the expression of inflammatory genes were similar in liver and jejunum mucosa. These data indicate that the effects of L-Met and DL-Met supplementation are comparable considering both piglet performance and parameters of gut health and function like gut morphology and the intestinal antioxidant status.

Efficacy of 2-hydroxy-4-methylthiobutanoic acid compared to DL-Methionine on growth performance, carcass traits, feather growth, and redox status of Cherry Valley ducks

The objective of this study was to compare the bio-efficacy of 2-hydroxy-4-methylthiobutanoic acid (DL-HMTBA) with that of DL-methionine (DLM) as sources of methionine in terms of the growth performance, carcass traits, feather growth, and redox statuses of Cherry Valley ducks. Six hundred and thirty male ducks were randomly allotted to 9 dietary treatment groups with 7 replicates of 10 birds each. The first group received a basal diet (BD) without methionine addition that was deficient in the total number of sulfur amino acids. In Groups 2 to 5 and Groups 6 to 9, the BD was supplemented with 4 increasing doses of methionine as either DLM or DL-HMTBA. The trial was run from ages 1 to 42 d. Dietary supplementation with DLM and DL-HMTBA improved body weight gain and feed intake as well as weights of carcasses, breast meat, and feathers compared with the BD. No significant difference was observed between the 2 methionine sources on growth performance, carcass traits, and feather growth. Concentrations of some redox markers in the pectoralis major muscle were improved by addition of methionine to the BD. However, a significant difference was observed between DLM and DL-HMTBA in this respect, as the supplementation of DL-HMTBA significantly increased the total antioxidant capacity, the activities of glutathione peroxidase, and the concentration of reduced glutathione in the pectoralis major muscle, compared with DLM. No significant difference between methionine sources was found with regard to the concentrations of oxidized glutathione and malondialdehyde in the pectoralis major muscle. Both DLM and DL-HMTBA increased malondialdehyde concentrations in the pectoralis major muscle compared with the BD. In conclusion, these results indicated that DLM and DL-HMTBA have equal biological value for the growth performance, carcass traits, and feather growth of Cherry Valley duck. Moreover, the improved antioxidant capacity observed with DL-HMTBA makes this a better candidate than DLM for lowering the oxidation process in the meat during post-mortem storage and thereby contributes to a better duck meat quality.

Comparative study on the utilization of crystalline methionine and methionine hydroxy analogue calcium by Pacific white shrimp (Litopenaeus vannamei Boone)

The objective of this study was to compare the supplemental effects of crystalline DL-methionine (DL-Met) and methionine hydroxy analogue calcium (MHA-Ca) on growth performance of Pacific white shrimp. Eight isoproteinic (355.3 ± 2.0 g/kg diet) and isolipidic (70.0 ± 2.2 g/kg diet) diets were prepared as positive diet (20% fish meal), negative diet (15% fish meal) and DL-Met, MHA-Ca-supplemented diets with the supplementation of 0.03%, 0.06%, 0.09% DL-Met and 0.04%, 0.07%, 0.1% MHA-Ca in negative diet respectively. Pacific white shrimp (0.92 ± 0.03 g) were fed one of the eight diets for 49 days. The results showed that dietary DL-Met did not affect weight gain (WG) and feed conversion ratio (FCR) (p > 0.05), but the supplementation of 0.1% MHA-Ca significantly increased WG, protein and lipid retention, and reduced FCR (p < 0.05) when compared to the negative group, and reached the similar levels as the positive control. The total free amino acids (TFAA) in haemolymph of MHA-Ca groups and PC, NC group peaked at the 3rd hr after feeding, but the peaking time of DL-Met groups was advanced to the 2nd hr. Activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in haemolymph of all MHA-Ca groups peaked at the 2nd hr, but DL-Met groups peaked at the 1st hr after feeding. The above results indicated that the supplementation of 0.1% MHA-Ca in a low fish meal diet could improve the growth performance and feed utilization of Pacific white shrimp, but dietary DL-Met did not significantly affect the growth.

Gene expression and activity of methionine converting enzymes in broiler chickens fed methionine isomers or precursors.

Common dietary supplemental methionine (Met) sources include DL-methionine (DL-Met) and the Met precursor DL-2-hydroxy-4-(methylthio) butanoic acid (DL-HMTBA). For bio-utilization, D-Met and DL-HMTBA are converted into L-Met through oxidation and transamination. The objective of this study was to determine the effect of different dietary supplemental Met sources on gene expression and enzyme activity of Met oxidases in male broiler chickens. Liver, muscle, duodenum, jejunum, and ileum were collected at days 10 (d 10), 21 (d 21), and 26 (d 26) post-hatch from male broiler chickens that were fed a basal diet deficient in sulfur amino acids (SAA) (control), or the control diet supplemented with DL-Met, L-Met, or DL-HMTBA to meet SAA requirements. The mRNA abundance of D-Met oxidase, L-HMTBA oxidase, and D-HMTBA oxidase was measured by real-time PCR, and oxidase activities were measured using colorimetric assays (n = 5). Liver expressed more D- and L-HMTBA oxidase mRNA, while breast muscle and liver expressed more D-Met oxidase mRNA than other tissues. In the liver, DL-HMTBA and L-Met supplementation were associated with greater mRNA abundance of L-HMTBA oxidase compared to the control diet-fed group at d 10 but not d 21 or d 26. DL-HMTBA supplementation, however, was not associated with changes in the mRNA abundance of D-HMTBA oxidase. The Met-deficient diet at d 26 was associated with greater hepatic abundance of DAO mRNA, which is responsible for oxidation of amino acids. Oxidase activities were similar among the Met deficient and Met-supplemented groups. In conclusion, dietary Met supplementation influenced the transcriptional regulation and activity of Met oxidases in a tissue and age-specific manner. Met oxidases may thus act as a determining factor in the bioefficacy of different dietary supplemental Met sources.

Effects of excess DL- and L-methionine on growth performance of starter Pekin ducks

A dose-response experiment was conducted to investigate the effects of excess DL-methionine (DLM) and L-methionine (LM) on growth response of starter Pekin ducks from 7 to 21 days of age. A total of 462 seven-day-old male Pekin ducklings were allotted to 77 wire-floor pens with 6 birds per pen. There were 11 treatments including a methionine-adequate control diet (containing 0.49% methionine) and control diets supplemented with 5 levels of crystal DLM or LM (0.25, 0.50, 0.75, 1.0, and 1.25%) based on equal product weight. At 21 d of age, weight gain, feed intake, and feed/gain of ducks from each pen were measured. In our study, the weight gain and feed intake did not change markedly and kept a plateau when supplemental DLM or LM was below 0.50%, but the weight gain and feed intake decreased further as supplemental DLM or LM increased from 0.50 to 1.25%. When the maximum safe level (MSL) of supplemental methionine sources and methionine content of the control diets were combined, the total tolerable upper limits of methionine for weight gain and feed intake were 0.91 and 0.85% when DLM was used, respectively, and the corresponding values were 0.89 and 0.84% when LM was used, respectively. On the other hand, both excess DLM and LM reduced weight gain and feed intake (P <0.05) but there were no significant differences (P >0.05) in weight gain and feed intake between the ducks fed DLM- and LM-supplemented diets. Furthermore, linear slope-ratio assay was also used to evaluate the relative toxicity of excess DLM and LM. According to this assay, the efficiencies of DLM relative to LM for depression of weight gain and feed intake were 97 and 95%, respectively. In summary, excess DL- and L-methionine were toxic for starter Pekin ducks and both methionine sources were equally growth depressing.

Methionine hydroxy analogue supplementation modulates gill immunological and barrier health status of grass carp (Ctenopharyngodon idella)

This study was conducted to investigate the effects of methionine hydroxy analogue (MHA) on the physical barrier and immune defence in the gill of young grass carp (Ctenopharyngodon idella). A total 630 young grass carp with an average initial weight of 259.70 ± 0.47 g were fed graded levels of MHA (0, 2.4, 4.4, 6.4, 8.5 and 10.5 g/kg diet) and one DL-methionine (DLM) group (6.4 g/kg diet) for 8 weeks. After feeding trial, 15 fish from each treatment were challenged with Flavobacterium columnare. Compared to the basal diet, optimal MHA improved cellular structure integrity of gill via repressing death receptor and mitochondria pathways induced apoptosis, which might be related to the down-regulation of c-Jun-N-terminal kinase mRNA levels (P < .05). Simultaneously, optimal MHA supplementation improved cellular structure integrity of gill via elevating glutathione contents, antioxidant enzymes activities and corresponding isoforms mRNA levels to attenuate oxidative damage, which might be to the up-regulation of NF-E2-related factor 2 mRNA levels and down-regulation of Kelch-like ECH-associating protein 1a mRNA levels (P < .05). Besides, optimal MHA improved intercellular structure integrity of immune organs via up-regulating the mRNA levels of intercellular tight junctions-related genes, which might be owing to the down-regulation of myosin light chain kinase (MLCK) mRNA levels (P < .05). Summarily, MHA could improve the physical barrier of fish gill. In addition, optimal MHA supplementation increased lysozyme (LZ) and acid phosphatase (ACP) activities, complement 3 (C3), C4 and immunoglobulin M contents and up-regulated mRNA levels of liver-expressed antimicrobial peptide 2, hepcidin and β-defensin, suggesting that MHA could enhance antimicrobial ability of fish gill. Meanwhile, optimal MHA supplementation enhanced the immune defence of gill via down-regulating pro-inflammatory cytokines mRNA levels and up-regulated anti-inflammatory cytokines mRNA levels, which might be attributed to the down-regulation of nuclear factor κB p65, c-Rel, IκB kinase β, p38 mitogen activated protein kinase, eIF4E-binding protein1 (4E-BP1) and 4E-BP2 mRNA levels and up-regulation of inhibitor of κBα, ribosomal protein S6 kinase 1 and target of rapamycin mRNA levels (P < .05). In conclusion, the positive effect of MHA on gill health is associated with the improvement of the defence against apoptosis, antioxidant status, tight junctions and immune defence of fish gill. Meanwhile, MHA was superior to DLM on improving the physical barrier of fish gill. For the direction to healthy breeding of young grass carp, the optimal MHA supplementation levels on the premise of 4.01 g/kg methionine basal were estimated by quadratic regression curve, such as 5.49, 6.17 and 6.02 g/kg diet bases on the defence against gill-rot, malondialdehyde content and LZ activity in the gill, respectively.

Effects of Dietary Supplementation of Lutein and DL-Methionine on Serum Antioxidant Profile and Cellular Immunity of Captive Golden Pheasants (Chrysolophus pictus)

Both carotenoids and methionine independently act as antioxidant and immune-modulator. As captive pheasant's diets are deficient in these nutrients, supplementation of either of these nutrients alone or in combination could be expected to be beneficial. Hence, this experiment was conducted to study the effect of supplementing lutein and DL-methionine on serum antioxidant status and cellular immunity of captive golden pheasants. Twenty-four adult male golden pheasants were randomly distributed into four groups of six each in an experiment based on 2×2 factorial designs. Basal diet contained no supplementary lutein or DL-methionine (M0C0). The diets of the birds in group M0C1 were supplemented with lutein (40 mg/kg DM) without supplementary DL methionine, whereas, those in group M1C0 were supplemented only with DL-methionine (1.5 g/kg DM). Birds in group M1C1 were fed both the supplements. Supplementation of lutein, but not DL methionine resulted in increased (P<0.01) serum concentration of total carotenoids, total antioxidant capacity and superoxide dismutase, along with reduced (P<0.01) concentration of malondialdehyde. Supplementation of both lutein and DL-methionine increased (P<0.01) serum concentration of reduced glutathione; however, the best response was observed when both the supplements were fed together. Supplementation of lutein increased the foot web index which is suggestive of improved cellular immunity. It is concluded that feeding of supplementary lutein at 40 mg/kg DM would improve the antioxidant status and cellular immune response of captive golden pheasants.

Growth Performance, Immune Response and Carcass Status of Broiler Chickens Fed Diets Contain Different Sources of Methionine

An experiment was conducted for a period of 42 days to assess the possible substitution of synthetic DL-methionine (DL-Met) by herbal methionine (H-Met) with graded levels on growth performance, immune response and carcass traits of broiler chicks. A total of 150-day-oldArber Acer chicks were randomly allotted into five experimental groups (30 chicks/group), each group with three replicates of 10 birds per replicate. Group 1 of birds was kept as a control group and the birds fed the basal diet containing the full methionine requirement (100%) from DL-Met without any H-Met substitution. While, other experimental groups fed on basal diet with DL-Met / H-Met at percentage of 75/25, 50/50, 25/75 and 0/100 for groups 2 – 5 respectively. The results showed that, 50% replacement of DL- Met by H- Met improved (P≥0.05) final body weight and weight gain by about 2.2% and 2.3% respectively when compared with chick of control group. H- Met inclusion had no effect on feed intake, while 50% replacement of 50% of synthetic methionine by H- Met non-significantly (P≥0.05) improved FCR, PER, EEU and PI by about 2.1%, 2.4%, 2.2% and 4.2% respectively when compared with the control. 50% replacement of synthetic Met by H- source non-significantly reduced blood serum triglyceride, cholesterol, GPT and ALP when compared with the control. 50% of synthetic Met replacement by H- Met synergistically together and had immune-stimulant effect and lower fat liver content of broiler chickens.

Different sources of sulfur in diets of adult cats on the urinary parameters and acid-base balance

ABSTRACT: Urolithiasis is a common disorder in the veterinary clinic and is considered as one of the most frequently cause of morbidity. This disorder is closely associated with urinary pH and nutrition plays a key role in the control of this disease, because through dietary manipulation it is possible to modify the urinary pH. Sulfur is considered macroelement with a strong influence on the acid-base status and may be crucial to control urinary pH in cats. The purpose of this study was to evaluate the effects of addition of different sources of sulfur (S) in the diet of cats on the urinary parameters and acid-base balance. Forty-two healthy adult cats were divided into 3 groups, and each group of 14 cats received 7 diets in a complete randomized block design. Calcium sulfate (CaSO4), DL-methionine (DLM) and methionine hydroxy analog (MHA) were added to a control diet in two levels (1.28g S/kg and 2.56g S/kg) to formulate 6 other experimental diets. The acid-base balance was evaluated by hemogasometry in samples of venous blood. The DLM at the highest level and MHA differed of the control diet in relation to urinary pH (P&lt;0.05). Calcium sulfate; although, not differentiated from the control diet, has been shown to alter urinary pH despite its zero electrolyte balance. Apparently, the alkalizing effect of calcium was not sufficient to avoid sulfate acidification of the urine. Treatments showed no alteration of the acid-base balance of the animals and no affect the consumption of the diets.