Methionine Hydroxy Analog Supplementation Research Articles

Evaluation of peripartum supplementation of methionine hydroxy analogue on beef cow–calf performance

The objective was to evaluate the effects of peripartum supplementation of a methionine hydroxy analogue (MHA) to primiparous, spring-calving beef females on dam and progeny performance. Angus heifers (n = 60) were blocked by expected parturition date, stratified by body weight (BW) and body condition score (BCS), and randomized to 1 of 15 pens. Pens were randomly assigned to 1 of 3 dietary treatments: a basal diet supplemented with 0 (M0), 15 (M15), or 30 (M30) g/animal/d of MHA (provided as MFP feed supplement, Novus International Inc., St. Charles, MO). Diets were fed from 45 ± 13 (SD) d pre-calving through 81 ± 13 d postpartum (DPP), after which all cow-calf pairs were managed as a single group on pasture until weaning (199 ± 13 DPP). Dam BW, BCS, and blood samples were taken at 6 predetermined timepoints. Progeny data were collected at birth, 2 intermediate timepoints, and at weaning. Milk samples were collected for composition analysis at 7 ± 2 DPP and at 55 ± 5 DPP. Serial progesterone samples were analyzed to establish resumption of cyclicity, and ultrasonography was performed at 55 ± 5 DPP to evaluate ovarian function. Cows were bred via artificial insemination at 82 ± 13 DPP and subsequently exposed to bulls for a 55-d breeding season. Pen was the experimental unit, and preplanned orthogonal contrasts were tested (linear effect and M0 vs. M15 + M30). Dam BW and BCS were not affected by treatment (P ≥ 0.29) throughout the study. Week 1 milk fat concentration increased linearly (P = 0.05) and total solids tended to increase linearly (P = 0.07) as MHA increased; however, no other milk components were affected (P ≥ 0.16). Treatment did not affect (P ≥ 0.16) dam reproductive parameters or progeny growth from birth until weaning. Post-calving, circulating methionine equivalents tended to linearly increase (P = 0.10) with increasing MHA supplementation. At breeding, plasma urea N linearly decreased (P = 0.03) with increased supplementation of MHA, and plasma non-esterified fatty acids were less (P = 0.04) in MHA-supplemented dams compared with dams receiving no MHA. Maternal circulating glucose, glutathione peroxidase, and thiobarbituric acid-reactive substances were not affected (P ≥ 0.15) by treatment at any point. These data indicate that peripartum supplementation of MHA may increase milk fat composition shortly after calving, but MHA supplementation did not improve progeny growth or dam reproductive performance in the current study.

Dietary methionine hydroxy analogue supplementation benefits on growth, intestinal antioxidant status and microbiota in juvenile largemouth bass Micropterus salmoides

To study the possible impacts of dietary methionine hydroxy analogue (MHA) on growth, intestinal antioxidant status, and intestinal microbiota in juvenile largemouth bass (LMB) Micropterus salmoides (14.49–14.58 g), we conducted a feeding trial for 84-days. Four hundred and eighty fish were randomized into four dietary MHA treatments (0.0, 3.0, 6.0, and 9.0 g/kg diet). Results revealed that dietary MHA supplementation: (1) dramatically improved growth of juvenile LMB; (2) markedly decreased intestinal protein and lipid peroxidation, and increased intestinal antioxidant activities via Keap1/Nrf2 axis; (3) increased the richness and diversity of intestinal microbial community; (4) changed intestinal microbiota composition, increased the abundances of Proteobacteria, Bacteroidetes, and Actinobacteria, and decreased the abundances of Firmicutes and Cyanobacteria at the phylum level; increased the abundances of Bifidobacterium and Bacillus and decreased the abundance of Bacteroides at the genus level. Collectively, dietary MHA supplementation has potential benefits in growth, intestinal antioxidant capacity, and intestinal microbiota in LMB. The dietary optimal Met level of LMB (14.49–131.06 g) was recommended to be 14.49 g/kg diet, corresponding to 8.30 g/kg diet sourcing from basic diet and 4.19 g Met/kg diet sourcing from MHA based on specific growth rate.

The effects of vitamin C and methionine hydroxy analog supplementation on performance, blood parameters, liver enzymes, thyroid hormones, antioxidant activity of blood plasma, intestine morphology, and HSP70 gene expression of broilers under heat stress

This experiment was performed to evaluate the effect of vitamin C and methionine hydroxy analog (MHA) on performance, blood parameters, liver enzymes, activity of selected hormones, antioxidant activity of blood plasma, intestine morphology, and HSP70 gene expression in broilers under heat stress. Four hundred 1-day-old male chickens of commercial Ross 308 strain were used in a completely randomized design with 4 treatments and 5 replicates of 20 chickens each. The experimental treatments were as follows: (1) base diet based on maize soybean (the control), (2) base diet with 0.2% vitamin C, (3) base diet with 0.46, 0.36, and, 0.32% methionine hydroxy analog, in the starter, grower, and finisher periods, respectively, and (4) base diet with a mixture of 0.2% vitamin C and 0.46, 0.36, and 0.32% of methionine hydroxy analog in the starter, grower, and finisher periods respectively. Although numerically higher than control, the effect of the experimental diets on performance was not significant across the experimental period (P>0.05). Glucose and LDL concentrations under all experimental treatments were significantly reduced compared to the control (P<0.05). The concentrations of liver enzymes (AST and ALT) and antioxidant activity (SOD, GPx, and MDA) of broilers were significantly different from the control under combined MHA and vitamin C supplementation (P<0.05). All experimental diets led to significantly increased T4 concentrations, compared to control (P<0.05). The length and width of intestinal villi of broilers were significantly increased in all of the experimental treatments compared to the control (P<0.05). The difference in HSP70 gene expression was significantly reduced in all of the treatments compared to the control (P<0.05). The results of this experiment showed that the use of vitamin C and methionine hydroxy analog (MHA) can be effective in reducing the negative effects of heat stress.

Methionine Hydroxy Analog Supplementation to Increase Feed Utilization for Indigenous Sheep

In the tropical area, productivity of ruminant has not optimized caused by the low quality of nutrition that leads to low-efficiency metabolism at the level of ruminal fermentation, post rumen digestibility, and intermediary metabolism. The study aimed to analyze effect of methionine hydroxy analog (MHA) on ruminal fermentation profiles of indigenous sheep specifically in the increase of ruminant productivity. In vitro utility test was conducted using rumen fluid of the indigenous sheep and sample of rational ration having a proportion of grass and concentrate 30%:70%, dry matter basis. The treatments implemented were three levels of MHA supplementation; T0: 0 g/day, T1: 3 g/day, and T2: 6 g/day. Variables measured were dry matter digestibility (DMD), organic matter digestibility (OMD), production of VFA, NH3, as well as total protein, and molar proportion of partial VFA of rumen fluid. Data were analyzed using analysis of variance (ANOVA) in a completely randomized design (CRD). The 0.2% MHA supplementation increased OMD with the highest production of total protein was from 28.57 mg/g (T0) to 40.49 mg/g (T2) (P&lt;0.05). Meanwhile, the lowest ratio of acetate : propionate was from 2.74 (T0) to 2.33 (T2) (P&lt;0.05). Supplementation of MHA up to 6 g/day concentrate increased the performance of fermentation and/or feed utility.

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 methionine hydroxy analogue supplementation on the expression of antioxidant-related genes of acute heat stress-exposed broilers

We evaluated the effects of heat stress (HS) and methionine supplementation on biological markers of stress and expression of the genes for superoxide dismutase (SOD), thioredoxin (TRx), thioredoxin reductase 1 (TRxR1) and methionine sulfoxide reductase A (MsrA) in broilers aged 1 to 21 or 22 to 42 days. The broilers were divided into two treatments, one with the recommended level of methionine supplementation (MS, supplementation of dl-2-hydroxy-4-methylthiobutanoic acid (dl-HMTBA)) and one without methionine supplementation (MD). The animals were maintained at a temperature of thermal comfort or one of HS (38°C for 24 h). Mortality was only observed in 42-day-old broilers exposed to HS and fed the MD diet, and the rate was 5%. Starter period: we observed an interaction effect between diet and temperature on the gene expression of TRxR1 and MsrA, and expression of these genes was higher in the HS animals that received the MS diet than that in birds with the MD diet. Grower period: the expression of SOD, TRxR1 and MsrA genes, activities of aspartate aminotransferase (AST) and creatine kinase (CK) and content of creatinine were influenced by both study variables. In the HS animals, the expression of these genes, AST activity and creatinine content increased and CK activity decreased. In the animals on the MD diet, the expression of these genes and AST and creatinine values were higher and the CK activity was lower than those for the birds on the MS diet. Our results indicated that under HS conditions, the supplementation with dl-HMTBA could mitigate major damage caused by stress through the action on some genes related to TRx complex activity.

Methionine hydroxy analogue improves intestinal immunological and physical barrier function in young grass carp (Ctenopharyngodon idella)

This study was conducted to test the hypothesis that methionine hydroxy analogue (MHA) enhances the defense against enteritis occurrence via improving intestinal barrier function in fish. After 630 young grass carp (Ctenopharyngodon idella) (259.70 ± 0.47 g) fed six graded levels of MHA (0, 2.4, 4.4, 6.4, 8.5 and 10.5 g/kg diet) and one dl-methionine group (6.4 g/kg diet) for 8 weeks. At the end of feeding trial, 15 fish from each treatment were challenged with Aeromonas hydrophila for 14 days. The results indicated that optimal MHA enhanced the capacity of fish against enteritis emergence, which might be related to the positive effects of MHA on intestinal immunological and physical barrier function in fish. Dietary MHA supplementation enhanced intestinal immunological barrier function via (1) lysozyme (LZM) and acid phosphatase (ACP) activities, complement 3 (C3), C4 and immunoglobulin M (IgM) contents and up-regulated mRNA levels of liver-expressed antimicrobial peptide 2, hepcidin (head kidney), β-defensin-1; (2) repressing p38MAPK/IKKβ/IκBα/NF-κB signaling pathway to down-regulate pro-inflammatory cytokines mRNA levels except IL-8 mRNA level only in mid and distal intestine; (3) potentiating TOR-signal cascades to up-regulate anti-inflammatory cytokines. Meanwhile, dietary MHA supplementation improved intestinal physical barrier via (1) down-regulating c-Jun N-terminal kinase mRNA levels to inhibit death receptor and mitochondria pathways induced apoptosis; (2) modulating Keap1a/Nrf2 system to elevate antioxidant enzymes genes isoforms mRNA levels and corresponding enzymes activities, subsequently alleviate oxidative damage; (3) down-regulating MCLK gene expression to up-regulating occludin, zonula occluden 1 and claudins mRNA levels except claudin-7a and claudin-7b only in the proximal intestine. In conclusion, bases on the capacity defense against enteritis, proximal intestinal malondialdehyde content and lysozyme activity, the optimal MHA supplementation levels were 5.83, 5.59 and 6.07 g/kg diet (4.01 g/kg methionine basal), respectively. This study indicates that MHA exerts a positive effect on fish intestinal health status and a superior efficacy to dl-methionine based on the positive effects.

Methionine hydroxy analogue enhanced fish immunity via modulation of NF-κB, TOR, MLCK, MAPKs and Nrf2 signaling in young grass carp (Ctenopharyngodon idella).

Our study investigated the effect of dietary methionine hydroxy analogue (MHA) on growth and immunity (head kidney, spleen and skin) of young grass carp (Ctenopharyngodon idella). A total of 630 grass carp (259.70±0.47g) were fed graded levels of MHA (0, 2.4, 4.4, 6.4, 8.5 and 10.5g/kg diet) and one dl-methionine (DLM) group (6.4g/kg diet) for 8 weeks. At the end of the feeding trial, fish were challenged with Aeromonas hydrophila for 14 days. The results indicated that optimal MHA increased lysozyme (LZ) and acid phosphatase (ACP) activities, complement 3 (C3), C4 and immunoglobulin M (IgM) contents and up-regulated mRNA levels of liver expressed antimicrobial peptide 2, hepcidin (head kidney), β-defensin-1 in the immune organs (P<0.05), suggesting that MHA could enhance antimicrobial ability of fish. Meanwhile, optimal MHA enhanced the immune function of immune organs 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<0.05). In addition, optimal MHA improved cellular structure integrity of immune organs 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<0.05). Simultaneously, optimal MHA improved cellular structure integrity of immune organs 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<0.05). 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 mRNA levels (P<0.05). In conclusion, MHA exerted a positive effect on the immune function and structural integrity of immune organs in fish. Furthermore, according to the positive effect, MHA was superior to DLM in grass carp. However, based on the growth performance, the efficacy of MHA relative to DLM was 97%. Finally, on the premise of the basal diet containing 4.01g/kg methionine, the optimal MHA supplementation levels based on feed intake, PWG, defense against skin hemorrhage and lesion, LZ and ACP activities, IgM content, against malondialdehyde, protein carbonyl and ROS in the head kidney of young grass carp were 5.07, 5.21, 5.76, 5.90, 5.88, 5.80, 6.22, 5.68 and 6.85g/kg diet, respectively.

Effects of fat and/or methionine hydroxy analog added to a molasses-urea-based supplement on ruminal and postruminal digestion and duodenal flow of nutrients in beef steers consuming low-quality lovegrass hay.

Five crossbred beef steers (initial BW = 338.6 ± 7.8 kg) fitted with ruminal and duodenal cannulas were used in a 5 × 5 Latin square design experiment to evaluate the effects of methionine hydroxy analog (MHA) and/or yellow grease (fat) added to a molasses-urea-based supplement on intake and characteristics of digestion. Steers were fed low-quality hay (long-stem lovegrass : 3.3% CP, 76.8% NDF; DM basis) ad libitum and supplemented with 0.91 kg/d (as fed) of 1 of 4 supplements in a 2 × 2 + 1 factorial arrangement of treatments. Supplemental treatments were 1) control (no supplement, NC); 2) molasses-urea liquid supplement (U); 3) U containing (as-fed basis) 1.65% MHA (UM); 4) U containing (as-fed basis) 12% fat (UF); and 5) U containing (as-fed basis) 1.65% MHA and 12% fat (UMF). Total and forage OM intake (kg/d and as % of BW) increased ( < 0.01) with molasses-urea, decreased ( ≤ 0.04) with MHA, and were not affected ( = 0.61) with fat supplementation. Total tract NDF digestibility increased ( = 0.01) with molasses-urea supplementation, and was less ( = 0.01) for fat than for nonfat supplementation. Total and microbial N flowing to the duodenum increased ( = 0.01) with molasses-urea supplementation. Although, total N flowing to duodenum was not affected ( = 0.27), microbial N decreased ( = 0.01), and nonammonia nonmicrobial N (NANMN) increased ( = 0.01) with fat supplementation. Extent of in situ OM and NDF digestibility at 96 h increased ( = 0.01) with molasses-urea supplementation, but were not affected ( ≥ 0.14) by either MHA or fat supplementation. Duodenal flow of total AA, essential AA, and nonessential AA increased ( ≤ 0.02) with molasses-urea supplementation. Total and nonessential serum AA concentration decreased ( < 0.01) with molasses-urea supplementation. Total ruminal VFA concentration increased ( = 0.01) with molasses-urea supplementation, and was not affected ( ≥ 0.14) by MHA or fat supplementation. Fat can be used in molasses-urea liquid supplements for cattle consuming low-quality forage to increase energy intake without negatively affecting forage intake or characteristics of digestion. However, adding MHA did not further improve the response to urea supplementation of cattle consuming low-quality forage. Conversely, the inclusion of MHA on urea supplement decreased forage intake.

Preliminary study on effects of methionine hydroxy analog and taurine supplementation in a soy protein concentrate-based diet on the biological performance and amino acid composition of rainbow trout [Oncorhynchus mykiss(Walbaum)

A feeding trial was conducted on the effects of methionine hydroxy analog (MHA) and taurine supplementation in diets with high levels of soy protein concentrate (SPC) on the growth performance and amino acid composition of rainbow trout, Oncorhynchus mykiss (Walbaum) comparing with fish meal based diet. The control diet had 520 g kg−1 fish meal. In the methionine deficient diets (5.1 g kg−1), fish meal was replaced by 490 g kg−1 of the SPC in the SPC49 diet. The SPC49 diet was supplemented with either MHA (6 g kg−1) only or a combination of MHA and taurine (2 g kg−1). Fish were fed isoproteic (460 g kg−1) and isolipidic (130 g kg−1) diets for 12 weeks. Growth performance (i.e. weight, feed conversion ratio, and thermal-unit growth coefficient) was inferior in fish fed the SPC49 diet. MHA supplementation improved growth performance (P < 0.05). No difference was observed when taurine was added to the SPC49 and MHA diet (P > 0.05). Whole-body taurine contents increased with taurine supplementation, whereas plasma methionine increased with MHA supplementation (P < 0.05). In conclusion, the substitution of fish meal with SPC supplemented with MHA did not negatively impact growth, and the addition of taurine did not improve growth performance in rainbow trout.

Effects of methionine hydroxy analog on voluntary intake, digestibility, nitrogen balance, and chewing behavior in sheep fed grass silage

Voluntary intake, digestibility, N balance, and chewing behavior of six 6-mo-old (young) and six 30-mo-old (mature) Texel wethers (32.6 and 83.1 kg average BW) given ad libitum access to grass silage and 100 g of top-dressed soybean meal with or without 5 g of methionine hydroxy analog (MHA) in the acid form were examined according to a two-period crossover design. Supplementation level of MHA in the acid form corresponded to .32 and .16 g of MHA/kg BW.75, respectively, in young and mature wethers. There was no effect (P greater than .10) of MHA on mean voluntary DMI. Methionine hydroxy analog supplementation increased (P less than .02) digestibility of DM, OM, and CP by young wethers but not (P greater than .18) by mature wethers. The MHA decreased eating time (P less than .03) in both young and mature wethers and intake level (P = .01) in young wethers during the first 1.5 h of access to grass silage. With MHA, both age groups increased (P less than .05) the daily number of meals and decreased (P less than .02) the mean duration of each meal. There was no effect (P greater than .06) of MHA on daily and unitary eating, ruminating, and masticating times; however, mean duration of consecutive rumination bolus cycles was longer (7.2%; P = .01) in young wethers. Young vs mature sheep ate more (53.4 vs 39.3 g of DM/[d.kg BW.75]; P less than .001) and had shorter unitary mastication times (P = .001). Results suggest that, depending on its relative level of supplementation, MHA in the acid form could act through both palatability and effects on ruminal metabolism.

Effects of Methionine Hydroxy Analog on Milk Secretion and Ruminal and Blood Variables of Dairy Cows Fed a Low Fiber Diet1,2

Twenty-eight Holstein cows were in a reversal trial to determine effects of adding 34 g/day of methionine hydroxy analog to a low fiber ration. Cows were subjected to this feeding treatment sequence after parturition: days 1 through 28, normal fiber ration; days 29 through 56, low fiber ration; days 57 through 77, low fiber ration with or without 34 g/day of methionine hydroxy analog; days 78 through 98, low fiber ration; days 99 through 119, low fiber ration with or without 34 g/day of methionine hydroxy analog (days 57 through 77 treatments reversed). Milk, rumen fluid, and blood were collected at regular intervals during each period. Overall, supplementation with methionine hydroxy analog increased only milk fat 6%. After milk fat percentage was depressed by low fiber diet, supplementation with methionine hydroxy analog increased milk fat percentage only for those cows that initially had less than 20% decrease of milk fat percentage. This enhanced milk fat percentage was accompanied by increase of ratio of ruminal acetate to propionate in animals with less than 10% depression. Supplementation with methionine hydroxy analog had no effect on blood glucose, insulin, or acetate concentrations and did not affect uptake of acetate by the mammary gland. Initial milk fat production affects the ability of methionine hydroxy analog supplementation to enhance milk fat percentage of dairy cattle fed low fiber diets.

Effect of Methionine Hydroxy Analog Supplementation on Dairy Cattle Hoof Growth and Composition1,2

Fifty lactating Holstein cows were assigned randomly to one of two treatments, control and control plus approximately 30g methionine hydroxy analog, and confined on concrete for 11 mo. The control diet consisted of sorghum silage and concentrate fed as a blended ration. Sulfur contents of dry matter were .12% and .16% for control and methionine hydroxy analog rations. Hoof growth and hardness were measured on front and rear right abaxial claws in the dorsal and lateral regions. Hoof growth rates were measured for four periods; summer-fall, fall-winter, winter-spring, and spring-summer, each 70 to 90 days. Hooves of cows fed methionine hydroxy analog grew faster than those of control cows during spring-summer in all regions. Variations of growth rates of hooves were seasonal and tended to follow variations in daily photoperiod. Wear rates were not affected significantly by treatment. Hooves of cows fed methionine hydroxy analog were softer in the top dorsal region at the end of winter-spring and in the dorsal toe region at the end of spring-summer. All other locations were not affected significantly by treatment. The toe region was harder than the top of the hoof. Cows fed methionine hydroxy analog had less cysteine and proline in hoof than control cows and greater percentages of methionine lysine, tyrosine, and glutamic acid. These results suggest that a decrease of disulfide bonding occurred in the hoof tissue of cows fed methionine hydroxy analog. Cows fed methionine hydroxy analog produced more actual milk, milk fat, and 4% fat-corrected milk during 180 days than did control cows.

The Effect of Methionine or Methionine Hydroxy Analogue Supplementation on Chick Response to Total Sulfur Amino Acid Intake

The results of four battery trials were used to compare the relative effectiveness of dl-methionine (DLM) and dl-methionine hydroxy analogue (M-analog) as supplements to soybean meal diets fed to broiler strain chicks. A total of 108 observations of 28-day body weight and corresponding total sulfur amino acid (TSAA) consumption were divided equally to form regression models based on TSAA intake containing either DLM or molecular equivalent amount of M-analog. At maximum effective TSAA intake, the predicted chick body weight resulting from DLM supplementation was 695 grams as compared to 693 from M-analog supplementation. At mean TSAA intake, predicted chick weights were 651 and 650 grams resulting from DLM, and M-analog supplementation, respectively. The pooled mean weight of unsupplemented controls was 584 grams. At low levels of supplementation, the linear change in weight per gram TSAA consumed was predicted to be 77.2 grams with DLM and 76.6 grams with M-analog.

Methionine Hydroxy Analog Supplementation of Low Protein Calf Rations1,2

Thirty-six Holstein calves were randomly assigned at 3 days of age to one of three complete calf rations: ration A, B, or C containing 0, .25, or .50% methionine hydroxy analog. All three rations were isonitrogenous at 13.5% crude protein (dry basis) and were offered adlibitum until calves were 12 wk of age. Calves were fed 3.64kg whole milk once daily for 4 wk. Average daily gains (kg) and dry matter intakes (kg) from 4 to 12 wk were .88, 2.49; .77, 2.50; and .56, 1.98 for calves fed A, B, and C. Weight gains differed between all rations while intake was higher for A and B than for C. Dry matter intakes (kg per kg gain) from 4 to 12 wk were 2.85, 3.32, and 3.54. Serum amino acids for five calves on each treatment were similar for A and B. Calves fed C had lower serum values for all individual essential amino acids compared to A and B and 28% lower circulating total essential amino acids. Serum cysteine increased as dietary methionine hydroxy analog increased. An amino acid imbalance or toxicity may have been produced which severely reduced gain, intake, and serum amino acids on ration C but only reduced gain on ration B.

Value of Methionine Hydroxy Analogue Supplementation of Broiler Rations

It has been shown that methionine hydroxy analogue will satisfy the methionine requirement of the chick (Bird, 1952; Gordon and Maddy, 1953). As part of an extensive program for testing the utility of methionine hydroxy analogue, experiments were carried out under conditions in which a high degree of control was maintained over temperature, light and other environmental factors. Data are presented to show that the type of experimental design employed demonstrates that the addition of low levels of methionine hydroxy analogue to practical broiler rations will give statistically significant improvements in feed efficiency. Experimetal work involving larger numbers of birds on floor trials or under field conditions will be reported subsequently.The basal diet used in this study was composed of soybean oil meal (44% protein) 35%, ground yellow corn 57.55%, alfalfa leaf meal 3.0%, dicalcium phosphate 1.975%, calcium carbonate 1.5%, iodized salt 0.5%, MnSO4 (70%) 0.025%. The following ingredients …