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The goal of this review article, based on a systematic literature search, is to critically assess the state of knowledge and experimental methodologies used to delineate the conversion and metabolism of the 2 methionine (Met) sources DL-methionine (DL-Met) and DL-2-hydroxy-4-(methylthio) butanoic acid (HMTBa). The difference in the chemical structures of HMTBa and DL-Met indicates that these molecules are absorbed and metabolized differently in animals. This review explores the methodologies used to describe the 2-step enzymatic conversion of the 3 enantiomers (D-HMTBa, L-HMTBa and D-Met) to L-Met, as well as the site of conversion at the organ and tissue levels. Extensive work was published documenting the conversion of HMTBa and D-Met into L-Met and, consequently, the incorporation into protein using a variety of in vitro techniques, such as tissue homogenates, cell lines, primary cell lines, and everted gut sacs of individual tissues. These studies illustrated the role of the liver, kidney, and intestine in the conversion of Met precursors into L-Met. A combination of in vivo studies using stable isotopes and infusions provided evidence of the wide conversion of HMTBa to L-Met by all tissues and how some tissues are net users of HMTBa, whereas others are net secreters of L-Met derived from HMTBa. Conversion of D-Met to L-Met in organs other than the liver and kidney is poorly documented. The methodology cited in the literature to determine conversion efficiency ranged from measurements of urinary, fecal, and respiratory excretion to plasma concentration and tissue incorporation of isotopes after intraperitoneal and oral infusions. Differences observed between these methodologies reflect differences in the metabolism of Met sources rather than differences in conversion efficiency. The factors affecting conversion efficiency are explored in this paper and are mostly associated with extreme dietary conditions, such as noncommercial crystalline diets that are very deficient in total sulfur amino acids with respect to requirements. Implications in the diversion of the 2 Met sources toward transsulfuration over transmethylation pathways are discussed. The strengths and weaknesses of some methodologies used are discussed in this review. From this review, it can be concluded that due to the inherent differences in conversion and metabolism of the 2 Met sources, the experimental methodologies (e.g., selecting different organs at different time points or using diets severely deficient in Met and cysteine) can impact the conclusions of the study and may explain the apparent divergences of conclusion found in the literature. It is recommended when conducting studies or reviewing the literature to properly select the experimental models that allow for differences in how the 2 Met precursors are converted to L-Met and metabolized by the animal to enable a proper comparison of their bioefficacy.

Methionine is an essential amino critical to many cell functions including the synthesis of proteins. Supplementation of methionine in vivo is typically through L-methionine, DL-methionine, or a methionine hydroxy analog (MHA). The goal of this study was to compare the function of L-methionine, DL-methionine, and an MHA as a source of methionine to myoblasts in vitro. Avian myoblasts isolated from turkey embryos were plated in media containing varying concentrations of DL-methionine (DLM; 1.125 mg/mL or 0.56 mg/mL) or methionine hydroxy analog (MHA; 1.28 mg/mL or 0.64 mg/mL) as well as a methionine deficient negative control group and an L-methionine supplemented positive control group. The results of the proliferation assay exhibited cell division in the absence of methionine which was not significantly different than the positive control group. Results from the myoblast fusion assay revealed significantly greater myotube diameter between methionine supplemented groups compared to the methionine deficient negative control. The findings of this study show an ability for avian myoblasts to proliferate in the absence of methionine, the significance of which is discussed. Additionally, findings from the fusion assay suggest that DL-methionine and MHA are potential cost-effective substitutes for methionine supplementation during terminal differentiation of avian myoblasts.

The present study investigated the interactive effects of copper sources and a high level of phytase on growth performance, nutrient digestibility, tissue mineral concentrations, and plasma parameters in nursery pigs. Weaning piglets (N = 192; 6.06 ± 0.99 kg), blocked by body weight, were randomly allotted to 1 of 4 dietary treatments, with 12 pens per treatment and 4 pigs per pen. A basal diet for each phase was formulated to meet nutrient requirements for nursery pigs with the exception that standardized total tract digestibility (STTD) P was reduced by 0.12% and Ca was adjusted to achieve Ca/STTD P = 2.15. The 4 dietary treatments were arranged in a 2 × 2 factorial design, with 2 Cu sources (125 mg/kg Cu from copper methionine hydroxy analogue chelate (Cu-MHAC) or copper sulfate (CuSO4)) and 2 phytase levels (0 or 1500 phytase units (FTU)/kg). Results showed that there was an interaction (P P 4. Pigs fed Cu-MHAC had greater apparent total tract digestibility (ATTD) of neutral and acid detergent fiber and STTD of P than those fed CuSO4. Phytase increased (P 4 when phytase was supplemented at 1500 FTU/kg. Cu-MHAC enhanced fiber and P digestibility regardless of phytase, compared with CuSO4. Phytase addition in P-deficient diets was effective in improving growth performance, Ca and P digestibility, and plasma inositol and growth hormone concentrations.

The study was conducted to determine the effects of mineral methionine hydroxy analog chelate (MMHAC) partially replacing inorganic trace minerals in sow diets on epigenetic and transcriptional changes in the muscle and jejunum of progeny. The MMHAC is zinc (Zn), manganese (Mn), and copper (Cu) chelated with methionine hydroxy analog (Zn-, Mn-, and Cu-methionine hydroxy analog chelate [MHAC]). On day 35 of gestation, 60 pregnant sows were allotted to two dietary treatments in a randomized completed block design using parity as a block: 1) ITM: inorganic trace minerals with zinc sulfate (ZnSO4), manganese oxide (MnO), and copper sulfate (CuSO4) and 2) CTM: 50% of ITM was replaced with MMHAC (MINTREX trace minerals, Novus International Inc., St Charles, MO). Gestation and lactation diets were formulated to meet or exceed NRC requirements. On days 1 and 18 of lactation, milk samples from 16 sows per treatment were collected to measure immunoglobulins (immunoglobulin G, immunoglobulin A, and immunoglobulin M) and micromineral concentrations. Two pigs per litter were selected to collect blood to measure the concentration of immunoglobulins in the serum, and then euthanized to collect jejunal mucosa, jejunum tissues, and longissimus muscle to measure global deoxyribonucleic acid methylation, histone acetylation, cytokines, and jejunal histomorphology at birth and day 18 of lactation. Data were analyzed using Proc MIXED of SAS. Supplementation of MMHAC tended to decrease (P = 0.059) body weight (BW) loss of sows during lactation and tended to increase (P = 0.098) piglet BW on day 18 of lactation. Supplementation of MMHAC increased (P < 0.05) global histone acetylation and tended to decrease myogenic regulatory factor 4 messenger ribonucleic acid (mRNA; P = 0.068) and delta 4-desaturase sphingolipid1 (DEGS1) mRNA (P = 0.086) in longissimus muscle of piglets at birth. Supplementation of MMHAC decreased (P < 0.05) nuclear factor kappa B mRNA in the jejunum and DEGS1 mRNA in longissimus muscle and tended to decrease mucin-2 (MUC2) mRNA (P = 0.057) and transforming growth factor-beta 1 (TGF-β1) mRNA (P = 0.057) in the jejunum of piglets on day 18 of lactation. There were, however, no changes in the amounts of tumor necrosis factor-alpha, interleukin-8, TGF-β, MUC2, and myogenic factor 6 in the tissues by MMHAC. In conclusion, maternal supplementation of MMHAC could contribute to histone acetylation and programming in the fetus, which potentially regulates intestinal health and skeletal muscle development of piglets at birth and weaning, possibly leading to enhanced growth of their piglets.

Our objective was to evaluate the lactational responses of dairy cows to methionine provided from 2 ruminally protected sources of methionine activity. Twenty-one Holstein dairy cows [11 primiparous (634 kg of body weight, 140 d in milk) and 10 second-parity (670 kg of body weight, 142 d in milk)] were assigned to a treatment sequence in 4 replicated 5 × 5 Latin squares plus 1 cow, with 14-d periods. Treatments were as follows: control; 7.5 or 15 g/d of a ruminally protected product of 2-hydoxy-4-methylthio-butyric acid (NTP-1401; Novus International Inc., St. Charles, MO); or 7.5 or 15 g/d of a ruminally protected dl-methionine product (Smartamine M; Adisseo, Alpharetta, GA). The diet was predicted to meet metabolizable protein and energy requirements. Diets contained 16.1% crude protein, and the control diet was predicted to be deficient in metabolizable methionine (1.85% of metabolizable protein) but sufficient in lysine (6.8% of metabolizable protein). Feed intake and milk yield were measured on d 11 to 14. Blood was collected on d 14. Dry matter intake, milk yield, energy-corrected milk, milk fat yield and percentage, and efficiencies of milk and energy-corrected milk yield were not affected by treatment. Milk protein percentage and milk protein yield increased linearly with supplementation, without differences between methionine sources or interactions between source and level. Linear regressions of milk protein percentage and milk protein yield against supplement amount within source led to slope ratios (NTP-1401:Smartamine M) of 95% for protein percentage and 84% for protein yield, with no differences between sources for increasing milk protein. Plasma methionine concentrations were increased linearly by methionine supplementation; the increase was greater for Smartamine M than for NTP-1401. Plasma d-methionine was increased only by Smartamine M. Plasma 2-hydoxy-4-methylthio-butyric acid was increased only by NTP-1401. Our data demonstrated that supplementation with these methionine sources can improve milk protein percentage and yield, and the 2 methionine sources did not differ in their effect on lactation performance or milk composition.

Trace minerals have important roles in immune function and oxidative metabolism; however, little is known about the relationships between supplementation level and source with outcomes in dairy cattle. Multiparous Holstein cows (n=48) beginning at 60 to 140 days in milk were utilized to determine the effects of trace mineral amount and source on aspects of oxidative metabolism and responses to intramammary lipopolysaccharide (LPS) challenge. Cows were fed a basal diet meeting National Research Council (NRC) requirements except for no added zinc (Zn), copper (Cu) or manganese (Mn). After a 4-week preliminary period, cows were assigned to one of four topdress treatments in a randomized complete block design with a 2×2 factorial arrangement of treatments: (1) NRC inorganic (NRC levels using inorganic (sulfate-based) trace mineral supplements only); (2) NRC organic (NRC levels using organic trace mineral supplements (metals chelated to 2-hydroxy-4-(methythio)-butanoic acid); (3) commercial inorganic (approximately 2×NRC levels using inorganic trace mineral supplements only; and (4) commercial organic (commercial levels using organic trace mineral supplements only). Cows were fed the respective mineral treatments for 6 weeks. Treatment effects were level, source and their interaction. Activities of super oxide dismutase and glutathione peroxidase in erythrocyte lysate and concentrations of thiobarbituric acid reactive substances (TBARS) and total antioxidant capacity (TAC) in plasma were measured as indices of oxidative metabolism. Effects of treatment on those indices were not significant when evaluated across the entire experimental period. Plasma immunoglobulin G level was higher in cows supplemented with organic trace minerals over the entire treatment period; responses assessed as differences of before and after Escherichia coli J5 bacterin vaccination at the end of week 2 of treatment period were not significant. Cows were administered an intramammary LPS challenge during week 5; during week 6 cows fed commercial levels of Zn, Cu and Mn tended to have higher plasma TAC and cows fed organic sources had decreased plasma TBARS. After the LPS challenge, the extent and pattern of response of plasma cortisol concentrations and clinical indices (rectal temperature and heart rate) were not affected by trace mineral level and source. Productive performance including dry matter intake and milk yield and composition were not affected by treatment. Overall, results suggest that the varying level and source of dietary trace minerals do not have significant short-term effects on oxidative metabolism indices and clinical responses to intramammary LPS challenge in midlactation cows.

The present study was conducted to evaluate the efficacy of organic acid blends as dietary antibiotic replacer in marine fish olive flounder, Paralichthys olivaceus. Fish averaging 3.5 ± 0.05 g (mean ± SD) were fed one of the four experimental diets: (1) without antibiotic or organic acid (Control/CON); (2) with antibiotic—50 mg oxytetracycline per kg body weight per day (OTC); (3) with organic acid blend A—4 g/kg diet (OAA); and (4) with organic acid blend B—4 g/kg diet (OAB), for 10 weeks. At the end of the experiment, total intestinal bacterial counts in fish‐fed OAA, OAB and OTC were significantly lower than that of fish‐fed CON diet (p

This study aimed to investigate the effect of increasing the standardized ileal digestible (SID) total sulfur amino acid to lysine (TSAA:Lys) on the growth performance of nursery pigs raised with or without antibiotics (AGP) and to determine the optimal SID TSAA:Lys in nursery pigs raised without AGP. In Exp. 1, 924 nursery pigs (7.9 ± 1.3 kg), blocked by initial BW and sex, were randomly allotted to one of six treatments, with seven pens per treatment and twenty-two pigs per pen. The treatments were arranged in a 2 × 3 factorial design, with two AGP levels (0 or 50 mg/kg Carbodox) and three levels of SID TSAA:Lys (51.0, 58.5 or 66.0%). In Exp. 2, 990 weaned piglets (5.1 ± 0.9 kg), blocked by initial BW and sex, were randomly allotted to one of five dietary treatments (SID TSAA:Lys at 51, 58, 65, 72 or 79%) in the absence of AGP, with nine pens per treatment and twenty-two pigs per pen. Competing heteroskedastic models including broken-line linear (BLL), broken-line quadratic (BLQ), and quadratic polynomial (QP) were fitted for the growth performance data to estimate the optimal TSAA:Lys. In Exp. 1, AGP supplementation increased (p &lt, 0.05) ADG and ADFI during the 21 d period. Increasing SID TSAA:Lys in the diets with AGP did not affect growth performance, however, increasing SID TSAA:Lys in the diets without AGP resulted in a linear increase (p &lt, 0.05) in ADG and G:F. In Exp. 2, the best-fitting models for ADG and G:F from d 0 to 21 post-weaning were BLL, which yielded the optimal SID TSAA:Lys of 62% and 72%, respectively. The best-fitting models for ADG and G:F from d 21 to 42 post-weaning were BLL, which yielded the optimal SID TSAA:Lys of 59% and 58%, respectively. In conclusion, SID TSAA to Lys requirements under an antibiotic-free feeding regime during the first 21 d post-weaning were 62% and 72% in terms of ADG and G:F, respectively, whereas an SID TSAA:Lys of approximately 58% was required to maximize ADG and G:F for the late nursery phase.

White Striping (WS) and Woody Breast (WB) are 2 conditions that adversely affect consumer acceptance as well as quality of poultry meat and meat products. Both WS and WB are characterized with degenerative myopathic changes. Previous studies showed that WS and WB in broiler fillets could result in higher ultimate pH, increased drip loss, and decreased marinade uptake. The main objective of the present study was to compare the proteomic profiles of muscle tissue (n = 5 per group) with either NORM (no or few minor myopathic lesions) or SEV (with severe myopathic changes). Proteins were extracted from these samples and analyzed using a hybrid LTQ-OrbitrapXL mass spectrometer (LC-MS/MS). Over 800 proteins were identified in the muscle samples, among which 141 demonstrated differential (P < 0.05) expression between NORM and SEV. The set of differentially (P < 0.05) expressed proteins was uploaded to Ingenuity Pathway Analysis® (IPA) software to determine the associated biological networks and pathways. The IPA analysis showed that eukaryotic initiation factor-2 (eIF-2) signaling, mechanistic target of rapamycin (mTOR) signaling, as well as regulation of eIF4 and p70S6K signaling were the major canonical pathways up-regulated (P < 0.05) in SEV muscle compared to NORM. The up-regulation of these pathways indicate an increase in protein synthesis which could be part of the rapid growth as well as cellular stress associated with ongoing muscle degeneration and the attempt to repair tissue damage in SEV birds. Furthermore, IPA analysis revealed that glycolysis and gluconeogenesis were the major down-regulated (P < 0.05) canonical pathways in SEV with respect to NORM muscle. Down-regulation of these pathways could be the reason for higher ultimate pH seen in SEV muscle samples indicating reduced glycolytic potential. In conclusion, comparison of proteomic profiles of NORM and SEV muscle samples showed differences in protein profile which explains some of the observed differences in meat quality parameters. Future studies based on these differences could provide valuable insights into various cellular changes and identification of biomarkers related to WS and WB.

Lameness is a welfare issue and is the most common involuntary reason for culling pigs. Study objectives were to compare objective measures of lameness to gait score and assess effects of dietary chelated trace minerals in finisher pigs. The study was a 2 x 2 factorial arrangement consisting of naturally- occurring lame vs healthy pigs and 2 dietary treatments: 1) metal methionine hydroxy analogue chelate (MMHAC) supplied as MINTREX® Zn-Cu-Mn (Novus International, Inc.) supplemented at 80-10-20 mg/kg diet; and 2) sulfates Zn-Cu-Mn supplemented at 120-20-40 mg/kg diet. The study consisted of 4 groups of pigs (50-70 kg; 8 lame/8 non-lame per group) staggered one month apart. Dietary treatments were fed 53d. Measurements included gait scoring (0-4) and a panel of serum biomarkers (P2CP, CTX2, C2C, CTX1, osteocalcin) and were measured at baseline, d28 and d53. Serum biomarkers included bone synthesis (osteocalcin), bone degradation (CTXI), cartilage synthesis (P2CP), and cartilage degradation (C2C, CTX2) as well as the ratio of synthesis/ degradation for a total of 8 biomarkers. Proc Mixed GLM procedure of SAS was used and means were determined using a Tukey test. The main effects of healthy vs lame and dietary treatment were significant, but no diet x lameness interactions were observed. Lame pigs had elevated CTX2 (P< .01), C2C (P=.02) and tended to have reduced ratio of P2CP:CTX2 (P=.09) compared to healthy pigs. MMHAC increased P2CP (P=.01) and P2CP:CTX2 ratio (P=.03) in both healthy and lame pigs compared to sulfates. These findings demonstrate that biomarkers can distinguish mildly lame pigs (average score of 1) from healthy pigs and lower concentrations of MMHAC vs commercial level of sulfates increased cartilage synthesis and the ratio of cartilage synthesis/degradation in both lame and healthy pigs.

The present experiment was conducted to evaluate the effects of trace mineral (Cu, Zn, Mn and Fe) premixes from inorganic and chelated (chelated to 2-hydroxy-4-methylthiobutanoic acid or hydroxy analog of methionine; Mintrex™, Novus International Inc., St. Charles, MO, USA) sources, in rockfish, (Sebastes schlegeli). fed diets containing mineral inhibitor phytic acid. Seven isonitrogenous (46% crude protein/CP) and isocaloric (16.63 KJ available energy per g diet) semi-purified diets comprising of a Basal control and diets supplemented either with the inorganic (I) or chelated premix (M) at three different levels of 0.75 (I0.75/M0.75), 1.5 (I1.5/M1.5) and 3 (I3/M3) g kg−1 diets were formulated. Twenty-four fish averaging individual wet body weight of 9 ± 0.2 g (Mean ± SD) were fed one of the experimental diets in quadratic group for 16 weeks. Average weight gain (WG) of fish fed M3 was significantly higher than that of fish fed Basal control and I1.5 diets (P

The present experiment was conducted to evaluate the efficacy of trace minerals (Cu, Zn and Mn) premixes from inorganic and chelated (chelated to 2-hydroxy-4-methylthiobutanoic acid or hydroxy analog of methionine; Mintrex™) sources, in juvenile Pacific white shrimp, ( Litopenaeus vannamei ) fed plant protein based practical diets. Eight experimental diets comprising a trace minerals (Cu, Zn and Mn) deficient Basal control, and diets supplemented with the trace mineral premixes at four different levels of 2.5 (M 2.5 ), 5 (M 5 ), 7.5 (M 7.5 ) and 8.5 g/kg (M 8.5 ) from chelated source and at three different levels of 5 (I 5 ), 8.5 (I 8.5 ) and 20 g/kg (I 20 ) from inorganic source were formulated. Eleven numbers of juvenile shrimp averaging 0.6 ± 0.01 g (mean ± SD) were fed one of the eight experimental diets in triplicate groups for 8 weeks. At the end of the feeding trial, shrimp fed M 2.5 and I 8.5 diets exhibited the similar final weight (FW) and weight gain (WG) ( P 5 compared to I 8.5 diet ( P Zn super oxide dismutase (Cu Zn SOD) from the serum and hepatopancreas tissue was recorded to be peaked for the group of shrimp fed M 5 diet. Moreover, plasma protein and glucose levels were recorded to be similar between the groups of shrimp fed M 2.5 and I 20 diets ( P L. vannamei ) fed plant protein based diets. Statement of relevance The significance of trace mineral bioavailability has become more important as the composition of majority of commercial fish feed has been changing and there is an increased use of dietary plant protein. As a result, the bioavailability of trace minerals is being adversely affected by the presence of antagonistic factor such as phytic acid in plant protein. Even though, our knowledge in fish nutrition has advanced significantly, the information on trace minerals requirement is still limited and fragmentary. Inorganic form (sulfate/nitrate) of trace mineral has traditionally been used in aquafeed formulation. However, the limited bioavailability of inorganic source of trace mineral due to its higher affinity to antinutrients has hastened the search for alternative form of inorganic trace minerals. Overall performance observed in the present experiments vouched the potential benefit of using chelated trace mineral, Cu, Zn & Mn premix in marine shrimp, Pacific white shrimp to promote the optimum growth, trace minerals saturation in shrimp body and tissue as well as to ensure the optimum enzyme activity and health of cultured shrimp. The present experiment opens a new avenue to compare the efficacy of inorganic and chelated source of trace minerals in other commercially important marine and fresh water fish species. Whereas, the sustainability issue has put a new dimension in aquafeed formulation with a wide array of new ingredients and additives, on the other hand, the importance of basic nutrient such as trace minerals is still in sideline. Substantial investment and integrated scientific efforts are warranted to bridge the knowledge gap and further improve our understandings on the significance of dietary trace mineral in fish nutrition and health at the least cost to environment.

Research has indicated that trace mineral (TM) supplementation may alter immune function and reduce morbidity associated with bovine respiratory disease. The objective of this experiment was to determine the influence of dietary Cu, Mn, and Zn supplementation on the performance, clinical signs, and TM balance of calves following a bovine viral diarrhea virus (BVDV) and (MH) combination respiratory pathogen challenge. Steers ( = 16; 225 ± 20 kg BW) from a single ranch were processed, weaned, and randomly pairwise assigned to either the TM-supplemented (MIN) or the control (CON) experimental treatments. The MIN calves received an additional 150 mg of Cu, 130 mg of Mn, and 320 mg of Zn daily and the CON calves received the basal diet with no additional Cu, Mn, or Zn supplementation. The basal diet contained sufficient Mn and Zn but inadequate Cu based on published nutrient requirements. After 46 d on the experimental treatments, all calves were naturally exposed to a heifer persistently infected with BVDV type 1b for 4 d and then subsequently intratracheally challenged with MH. Data were analyzed using the GLIMMIX procedure of SAS with sampling time serving as a repeated measure and calf serving as the experimental unit. The respiratory challenge was validated via increased BVDV type 1b antibody concentrations, MH whole cell and leukotoxin antibody concentrations, rectal temperatures (TEMP), and subjective clinical severity scores (CS). Calf performance ( ≥ 0.48) was not affected by TM supplementation. Mineral supplementation also did not impact the CS or TEMP of calves ( ≥ 0.53). There was a treatment × time ( < 0.001) interaction observed for liver Cu concentrations. The concentrations of Cu, Mn, Zn, and Fe within the liver; Cu, Mn, and Zn within the muscle; and Cu, Zn, and Fe within the serum were all impacted by time ( ≤ 0.03). Calves receiving the MIN treatment had greater ( < 0.01) liver Cu and Mn concentrations compared with CON calves. In contrast, serum Cu and Fe concentrations were increased ( ≤ 0.05) in CON calves compared with MIN calves. Mineral supplementation did not impact TM concentrations within the muscle ( ≥ 0.38). The supplementation of Cu, Mn, and Zn can improve the Cu and Mn status within the liver and serum of calves in response to a BVDV and MH challenge. When Cu is supplemented to calves receiving a marginally Cu-deficient diet, Cu status within the body is significantly improved.

Lameness in gilts and sows has an economic impact on pig production and is a major welfare concern. Study objectives were to compare subjective and objective lameness measurements and assess efficacy of chelated trace minerals in finisher pigs. Two dietary treatments: metal methionine hydroxy analogue chelate (MMHAC) supplied as MINTREX® Zn-Cu-Mn (Novus International, Inc.) supplemented at 80-10-20 mg/kg diet; and sulfates Zn-Cu-Mn supplemented at 120-20-40 mg/kg diet were fed. Four groups of pigs (50-70 kg; 8 pigs/grp) were fed dietary treatments for a duration of 8 wk prior to injection of 2 mg sodium urate crystals into the right rear distal interphalangeal joint. Data collection occurred at baseline, 6, 12, 24, 48, 72 and 144 hr post-urate injection. Measurements included gait scoring (0-4), a panel of serum biomarkers for synthesis and degradation of cartilage (P2CP, CTX2, C2C), bone (osteocalcin, CTX1) and static force-plate. A Proc Mixed GLM procedure of SAS was used and means were determined using a Tukey test. Urate injections resulted in elevated gait scores, peaking at 12 hr and similar to baseline at 72 hr; pigs fed MMHAC had lower gait scores (P< 0.01) compared to sulfate. C2C (P=0.09), CTX2 (P=0.10) and osteocalcin (P< 0.01) paralleled closely to changes in gait score, peaking at 12 h and returning to baseline at 24 to 72 hr. Osteocalcin (P=0.07) and osteocalcin: CTX1 ratio (P=0.05) were increased with MMHAC. These findings demonstrate that biomarkers can distinguish between healthy vs lame pigs and MMHAC, at lower concentrations vs sulfates, reduced gait score and increased osteocalcin.

Three experiments were conducted to quantify the efficacy of exogenous protease in poultry diets containing soybeans with varying trypsin inhibitor (TI) concentrations. Test diets contained 4 g/kg of TiO2 as a digestibility marker and protease (CIBENZA® DP100 at 300 U/g diet, Novus International). A randomized complete block design was analyzed using ANOVA with LSD multiple pair-wise comparison used to compare treatment means. For Exp 2 and 3, a common starter diet was fed to broiler chickens until d 16 of life and then switched to test diets. Exp 1 was a 2×6 factorial arrangement of 2 protease levels (0 and 300 U/g) and 6 dietary TI levels (0.72, 1.16, 1.61, 2.06, 2.50, and 2.95 mg/g) with 6 replicates/treatment; 8 chicks/pen. In Exp 2 (12 replicates/treatment; 8 chicks/pen), apparent ileal AA digestibility (AIAAD) was evaluated in diets containing 250 g/kg full fat extruded soybeans (FFES)+SBM (negative control; 5.8 mg/g TI) with or without protease or SBM (positive control; 3.1 mg/g TI). Test diets were fed from d 16–21 of age, AIAAD and relative pancreas weight was measured on d 21. In Exp. 3, broilers were allocated to a 2×2 factorial arrangement of treatments with 9 replicates/treatment and 8 chicks/pen. The dietary factors were SBM inclusion (420 or 960 g/kg; SBM TI = 3.85 mg/g), or protease inclusion (0 or 300 U/g). Test diets were fed from d 22–30, ileal digesta was collected on d 30. With increasing TI, pancreas weight increased (P

This study investigated the interactive effects of Zn sources, Cu sources and phytase on growth performance in nursery pigs. A total of 288 weaning barrows (BW = 5.71 ± 0.81 kg), blocked by initial body weight, were randomly allotted to 1 of 8 dietary treatments, with 9 pens per treatment and 4 pigs per pen. The 8 dietary treatments were arranged in 2 × 2 × 2 factorial design, with 2 Zn sources [2000 ppm Zn from ZnO during phase 1 (d 1 to 14) and 2 (d 15 to 28), and 100 ppm Zn from ZnO during phase 3 (d 29 to 42); 100 ppm Zn from Zn methionine hydroxy analogue chelate (Zn-MHAC, MINTREX® Zn, Novus International Inc., St. Charles, MO) during phase 1 to 3], 2 Cu sources [150 ppm Cu from CuSO4 or Cu-MHAC (MINTREX® Cu) during phase 1, and 80 ppm Cu from CuSO4 or Cu-MHAC during phase 2 and 3], and 2 phytase inclusion levels (0, 500 FTU/kg). Results showed that there were no differences (P > 0.10) between ZnO and Zn-MHAC groups in terms of growth performance during the entire nursery period. Compared with CuSO4, Cu-MHAC tended to increase ADG (P = 0.07) and G:F (P = 0.08) during the entire nursery period. There tended to be an interaction (P = 0.09) between Cu sources and phytase on G:F during phase 2. Specifically, without phytase supplementation, there was no difference (P = 0.63) on G:F during phase 2 between Cu-MHAC and CuSO4, whereas with phytase supplementation, Cu-MHAC increased G:F during phase 2 (P = 0.05) compared with CuSO4. In conclusion, Zn-MHAC supplementation at 100 ppm could replace pharmacological level of ZnO without affecting growth performance. Cu-MHAC could improve growth performance compared with CuSO4. Cu-MHAC exerted synergistic effect with phytase on improving feed efficiency.

A multitrial analysis was conducted to evaluate the effect of different levels of Cu from either Cu(2-hydroxy-4-(methylthio)butanoic acid [HMTBa])2 or CuSO4 on growth performance in nursery pigs. Six nursery trials were conducted from 2007 to 2012 under the same commercial conditions with initial BW of 5.75 ± 0.41 kg at 21 ± 3 d of age; the trials lasted for 42 d with a 3-phase feeding program (7 d in Phase I, 14 d in Phase II, and 21 d in Phase III). Diets were medicated with antibiotics and supplemented with 3,000 mg/kg Zn as ZnO during phases I and/or II. Treatments included a basal diet without added Cu or according to the NRC (1998) and supplemental levels of Cu (50 to 250 mg Cu/kg diet) from either Cu(HMTBa)2 or CuSO4; HMTBa was supplemented to make diets isomethionine. Treatments from each trial included 6 or 9 replicate pens/treatment with 22 to 25 piglets/pen. Mixed model analysis was conducted in which trial was considered a random effect, Cu level was considered a continuous fixed effect, and Cu source was a fixed effect. The basal diet within trial and statistical tests of the intercept between sources were not different, resulting in fitting a common intercept mixed model to the overall responses across phases. Cumulative ADG and ADFI quadratically responded (P < 0.05) with increasing Cu supplementation; predicted optimal ADG and ADFI occurred at 174 and 119 mg/kg, respectively. Increasing Cu supplementation linearly improved G:F (P = 0.054). No differences between sources were observed in ADG or ADFI. Numerically, pigs fed Cu(HMTBa)2 had higher ADG and lower ADFI compared to pigs fed CuSO4, resulting in better G:F for pigs supplemented with Cu(HMTBa)2 compared to pigs supplemented with CuSO4 (P < 0.01). The linear slope for increasing Cu supplementation on G:F was 2.1-fold higher for Cu(HMTBa)2 than that of CuSO4, with larger differences occurring in Phase II. In conclusion, Cu supplementation in nursery diets resulted in improved performance and Cu(HMTBa)2 is more effective than CuSO4 in improving feed efficiency.

The objective of this experiment was to test the effect of a Met analog, 2-hydroxy-4-methylthio-butanoic acid (HMTBa), on ruminal fermentation and microbial protein synthesis, nutrient digestibility, urinary N losses, and performance of dairy cows. Eight multiparous lactating Holstein dairy cows were assigned to 4 levels of HMTBa [0 (control), 0.05, 0.10, and 0.15% (dry matter basis)] in a replicated 4×4 Latin square trial. Experimental periods were 28 d, including 21 d for adaptation. Ruminal ammonia and microbial N were labeled through a 6-d intraruminal infusion of (15)NH4Cl, and microbial protein synthesis in the rumen was estimated using the reticular sampling technique. Treatment had no effect on dry matter intake (28.4 to 29.8kg/d), milk yield (44.1 to 45.3kg/d), feed efficiency, and milk composition. Total-tract apparent digestibility of nutrients was generally not affected by treatment, except digestibility of crude protein and starch decreased quadratically with HMTBa supplementation. Fecal, but not urinary, and total excreta N losses were increased quadratically by HMTBa. Ruminal pH, ammonia concentration, protozoal counts, and the major volatile fatty acids were not affected by treatment. Microbial N outflow from the rumen was linearly increased by HMTBa. 2-Hydroxy-4-methylthio-butanoic acid linearly increased the proportion of Fecalibacterium and quadratically decreased the proportion of Eubacterium in ruminal contents. Of the individual bacterial species, HMTBa increased or tended to increase Prevotella loescheii and Prevotella oralis. 2-Hydroxy-4-methylthio-butanoic acid linearly increased the concentration (and yield) of 15:0 in milk fat. In the conditions of this crossover experiment, HMTBa had no effect on feed intake and performance of dairy cows, decreased dietary crude protein digestibility, and increased microbial N outflow from the rumen.

The objectives of our study were to evaluate the productive response to methionine supplementation in lactating dairy cows and to define a relationship between metabolizable Met (MP Met) intake and production. A database of 64 papers meeting the selection criteria was developed evaluating postruminally infused dl-methionine (9 papers with 18 control diets and 35 treatment comparisons), 2-hydroxy-4-methylthio butanoic acid (HMTBa) provided as either a liquid or Ca salt form (17 papers with 34 control diets and 46 treatment comparisons), Mepron (Evonik Industries, Essen, Germany; 18 papers with 35 control diets and 42 treatment comparisons), and Smartamine (Adisseo Inc., Antony, France; 20 papers with 30 control diets and 39 treatment comparisons). Dietary ingredients and their accompanying nutritional compositions as described in the reports were entered into the Cornell-Penn-Miner software to model the diets and to predict nutrients that were not reported in the original publication. Data were analyzed using a weighted analysis of response to supplementation compared with the intraexperiment control, as well as through a regression analysis to changing dietary MP Met. Data included in the analysis were from experiments published between 1970 and 2011 with cows supplemented with between 3.5 and 67.9 g of Met or its equivalent from HMTBa. Cows supplemented with Smartamine consumed more, whereas cows supplemented with Mepron consumed less DM compared with controls. Milk yield did not significantly respond to Met supplementation, although it tended to increase for cows supplemented with HMTBa and Mepron. Milk protein yield was increased due to supplementation from all sources or from infusion, and protein concentration was greater for all supplements or infusion of dl-Met, except for cows supplemented with HMTBa. Irrespective of Met source, milk protein yield increased 2.23 g of protein/g of MP Met until reaching the breakpoint. Milk fat yield was increased for Mepron and HMTBa, whereas milk fat concentration was increased for infused dl-Met and for cows supplemented with HMTBa. Based on regression analysis, response of milk fat yield to Met supplementation was not different for infused dl-Met, Mepron, and Smartamine (1.87 g of fat/g of MP Met), whereas the response to HMTBa was significantly greater at 5.38 g of fat/g of MP Met.

The objective of this experiment was to measure the apparent total tract digestibility (ATTD) and the retention rate of Zn, Cu, Mn, and Fe in pigs fed either inorganic or organic sources of Zn, Cu, Mn, and Fe. The experimental design was a randomized complete block design with a 2 × 3 factorial arrangement of treatments. There were 2 types of diets (corn grits-based or corn-soybean meal [SBM]-based diets) and 3 micromineral treatments (basal micromineral premix [BMM], inorganic micromineral premix [IMM], and organic micromineral premix [OMM]). The BMM contained no added Zn, Cu, Mn, or Fe; the IMM microminerals were provided as sulfates of Zn, Cu, Mn, and Fe at 40, 50, 20, and 100 mg/kg, respectively. The OMM contained the same levels of the 4 microminerals as IMM, but Zn, Cu, Mn, and Fe in this premix were provided by Zn(2-hydroxy-4-methylthio butanoic acid [HMTBa])2, Cu(HMTBa)2, Mn(HMTBa)2, and FeGly, respectively. Forty-eight barrows (initial BW: 31.1 ± 4.2 kg) were housed individually and allowed ad libitum access to the corn grits diet with BMM for 2 wk. All pigs were then moved to metabolism cages and randomly assigned to 1 of the 6 treatment diets with 8 replicates per diet. Fecal and urine samples were collected for 5 d following a 5-d adaptation period. Compared with corn grits diets, pigs fed corn-SBM diets had greater (P < 0.05) absorption and retention of Zn, Cu, and Mn but less (P < 0.05) ATTD of Zn and Cu. Compared with BMM, supplementation of IMM or OMM increased (P < 0.05) absorption, retention, ATTD, and retention rate of Zn, Cu, Mn, and Fe. Compared with IMM, adding OMM to the corn-SBM diet improved (P < 0.05) the absorption and retention of Cu and Mn and the ATTD of Cu, but these differences were not observed in the corn grits diets (interaction, P < 0.05). In addition, adding OMM to the corn-SBM diet increased (P < 0.05) absorption and retention of Zn and Fe and ATTD of Zn, Mn, and Fe compared with adding IMM to the corn-SBM diet. Supplementation of OMM also increased (P < 0.05) the ATTD and retention rate of P in corn-SBM diets. Results indicate that Zn(HMTBa)2 has greater digestibility and Cu(HMTBa)2 and Mn(HMTBa)2 have greater digestibility and retention rates compared with their inorganic sulfates, if included in a corn-SBM diet. Supplementation of organic microminerals also improves the digestibility of P in a corn-SBM diet.

In 2011, aquaculture accounted for almost 64 million MT of fish, crustaceans and mollusks (FAO, 2012). Fish meal has historically been the protein source of choice in aquatic feeds, but global supplies have reached a plateau making it less available and more expensive. As a consequence, the use of cheaper proteins made from processed plant proteins, byproducts from agriculture, fisheries or the slaughtering of terrestrial production animals was popularized within the aquaculture feed industry. Although these alternative ingredients may contain a crude protein (CP) content comparable to fish meal, they may be less digestible and deficient in one or more of the ten essential amino acids (EAAs). This has required the adoption of more modern formulation approaches which take into account nutrient availability, especially in regard to EAAs. EAA requirements have been established for a number of species of fish and shrimp. Methionine (Met) followed by lysine (Lys) are the first limiting amino acids in plant and rendered animal byproducts. Formulating for EAAs by simply increasing the dietary inclusion levels of the feedstuffs that contain intact sources of the targeted EAAs can lead to overformulated feeds with excessive levels of CP and other nutrients. A more rational approach is to supplement the diet with crystalline amino acids (CAAs). A first step to the application of a nutrient-based formulation approach is knowledge of the digestible EAA content of the ingredients available for use in the formula. It is highly desirable to formulate on a CP, EAA and energy digestibility basis in line with current formulation practices of most modern feed companies. Further expansion of current EAA digestibility values across ingredients and farmed aquatic species will further enable nutrient based formulation. By formulating on an EAA basis across farmed aquatic species, nutritionists have realized least cost formulation opportunities with the use of CAAs which are now available throughout the world at accessible prices. The CAAs mostly used by the animal feed industry, in order of usage, are the following: dl -methionine or Met analogs, l -lysine, l -threonine, l -tryptophan, l -isoleucine and l -valine. Met and Lys are the most currently used due to their wide availability and importance as most limiting EAAs in plant protein ingredients, such as soy and corn based meals. There is a relatively wide variation in the dietary Met and Lys requirement values for farmed fish and shrimp. This is due to differences in species requirements, culture systems, developmental stage and composition of experimental diets. The dietary Met requirements for fish and shrimp range from 0.5 to 1.5% and from 0.7 to 0.9% of the diet, respectively (NRC, 2011). The dietary Lys requirements range from 1.2% to 3.3% of the diet for cultured fish and from 1.6 to 2.1% of the diet for cultured shrimp. Appropriate dietary Met and Lys levels improve the use of other EAAs because they have the ability to reduce the oxidation rate of other amino acids. The present review discusses bioavailability, requirements and sources of EAAs and practical considerations for their application in aquaculture feeds. The appropriate supplementation of crystalline amino acids in feeds for fish and shrimp represents an opportunity to reduce formulation costs in the face of the volatile commodity market of protein ingredients and the short supply of fish meal. Competitiveness in the aquatic animal feed industry today depends upon application of modern and environmentally-sound formulation techniques based on nutrient value and supplementation with crystalline EAA to meet animal nutrient requirements.

White striping (WS) and woody breast (WB) are 2 poultry meat quality defects that affect the acceptance of raw breast fillets as well as properties of cooked and further processed products. The present study was intended to evaluate the incidence of these conditions in broilers at different ages and to compare the properties of fillets with different degrees of WS and WB. For this study, 1,920 birds were processed, at 6 and 9 wk of age, in a standard commercial inline processing system. After chilling, carcasses were deboned and butterfly fillets were collected and weighed. Individual fillets were scored for normal, moderate, severe, and very severe degrees of WS and WB, and for petechial hemorrhagic lesions (PHEM, 0 - no lesion to 2 - severe lesion). Representative fillets with NORM-WS/WB, SEV-WS, SEV-WB, and SEV-WS/WB were selected and stored at 4°C. After 24 h, fillet length, width, cranial height, and caudal height, as well as pH, color, and drip loss were recorded. There was an increase in incidence of severe and very severe WS and WB conditions at 9 wk compared to 6 wk of age. The relationship between fillet weight and the myopathies plateaued at 9 wk of age with more fillets showing a higher score. Mean PHEM scores were higher (P < 0.05) in SEV-WS, SEV-WB, and SEV-WS/WB compared to NORM-WS/WB birds, both at 6 and 9 weeks. NORM-WS/WB birds had lower (P < 0.05) live and breast weight, breast yield, and cranial and caudal heights, as well as b* value (yellowness) compared to SEV-WS/WB. NORM-WS/WB had lower (P < 0.05) pH while NORM-WS/WB and SEV-WS samples showed lower (P < 0.05) drip loss when compared to SEV-WB and SEV-WS/WB. The results from this study showed that the severe degrees of WS and WB are associated with heavier and older birds, and thicker breast fillets. Occurrence of severe degrees of WS and/or WB can affect various raw meat quality factors, mainly color and water holding capacity.

An experiment was conducted to characterize a gut health challenge model consisting of a diet containing rye, wheat, and feather meal and a mild mixed-species Eimeria challenge, and to evaluate the effect of carbohydrase and protease on growth performance and gut health of young broilers. The study included 4 treatments: negative control, carbohydrase alone, protease alone, and combination of carbohydrase and protease. Each test diet was fed to 18 battery pens of broilers with 8 male birds per pen from 0 to 22 d of age. Carbohydrase improved body weight, feed intake, and feed conversion ratio (FCR) on d 7, 14, and 21(P < 0.01). Protease increased body weight on d 7 and 21 and improved 0 to 7 d FCR (P < 0.05). More lymphocyte infiltration was observed in small intestine mucosa of negative control birds on d 8, carbohydrase supplementation lessened this. Both carbohydrase and protease reduced digesta viscosity on d 22 with the carbohydrase effect being the greater of the two, and the combination effect was not different from the carbohydrase effect alone (P < 0.01). Ileal Clostridium perfringens of 15-day-old broilers was decreased by carbohydrase, a further reduction was achieved by combining carbohydrase with protease (P = 0.01). Liver vitamin E concentration on d 15 (P < 0.01) and 22 (P = 0.02) was increased by carbohydrase, and the carbohydrase effect was greater in the presence of protease on d 22 (P = 0.04). Plasma α-1-acid glycoprotein level and liver Zn and Cu concentrations of broilers were reduced by carbohydrase on d 15 (P < 0.01). Broilers fed carbohydrase had higher levels of plasma zeaxanthin on d 22 and higher levels of plasma lutein on d 15 and 22 (P < 0.01). In summary, a rye wheat based diet containing feather meal when fed to broilers in addition to a mild Eimeria challenge induced subclinical enteritis characterized by digestion inefficiency, dysbacteriosis, inflammation, and gut barrier failure; carbohydrase and protease could be effective tools to improve growth performance and gut health of broilers suffering from this type of subclinical enteritis.

SUMMARY Two 54-d grow-out trials were conducted in a commercial broiler facility to determine the effect on performance, carcass yield, footpad lesions, and litter trace mineral concentrations when feeding broiler chicks diets containing reduced levels of chelated Zn-(HMTBA)2 [where HMTBA is 2-hydroxy-4-(methylthio)butanoic acid; trials 1 and 2], Cu-(HMTBA)2 (trial 2), and Mn-(HMTBA)2 (trial 2) in comparison with industry levels of the respective inorganic trace minerals (ITM). A total of 122,400 Ross 708 straight-run chicks were distributed into 8 houses with approximately 15,300 chicks per house for trials 1 and 2, with 4 replicate houses per treatment. Treatments in trial 1 consisted of 30 ppm of Zn as chelated Zn-(HMTBA)2 and 100 ppm of Zn as ZnSO4 (ITM). In trial 2, treatments consisted of 32, 8, and 32 ppm from Zn-, Cu-, and Mn-(HMTBA)2, respectively, and 100, 125, and 90 ppm of Zn, Cu, and Mn, respectively, as sulfates (ITM). Trial 1 was carried out on built-up litter, and trial 2 was on fresh litter. In trials 1 and 2, no differences (P > 0.05) were observed in performance, carcass yield, or tibia Zn over the 54-d period between treatments. On d 54 (trial 1), chicks fed diets supplemented with Zn-(HMTBA)2 had 27.3% more grade 1 and 2 paws than those fed ITM (P < 0.01). On d 54 (trial 2), the chicks fed Zn-, Cu-, and Mn-(HMTBA)2 had 23.3% more grade 1 and 2 paws than those fed ITM (P = 0.07). For trial 2, litter Zn, Cu, and Mn from birds fed Zn-, Cu-, and Mn-(HMTBA)2 were reduced by 40, 74, and 35%, respectively, compared with birds fed the respective ITM. In summary, based on the present data, commercial levels of ITM can effectively be replaced with reduced levels of Zn-, Cu-, and Mn-(HMTBA)2 without compromising bird performance while achieving a significant improvement in footpad health and a reduction in trace mineral concentrations in the litter.

The objectives of the current study were to determine the fate and contribution to Met kinetics of 2-hydroxy-4-(methylthio)butanoate (HMTBA) at the whole-body, splanchnic, and mammary levels. Four multicatheterized cows (31.3 kg of milk/d; 17.7 kg of DMI/d) were used in a crossover design, with two 1-wk periods, to determine the metabolic fate of HMTBA and its effect on Met metabolism. Over the last 2 d of each period, cows were infused, via a jugular vein, with saline or HMTBA (Alimet, Novus International Inc., St. Louis, Mo) at the rate of 36 g/d. During the last 8h, the HMTBA infusion was substituted by equimolar [1-(13)C]HMTBA (8.79 mmol/h) and l[methyl-(2)H(3)]Met (1.31 mmol/h) was infused in all cows. During the last 5h, hourly samples (n=6) were collected to determine plasma flows plus the isotopic enrichments (IE) and concentrations of HMTBA ((13)C) and Met (both (13)C and (2)H(3)) in plasma from an artery plus portal, hepatic, and mammary veins. The IE of [(13)C] and [(2)H(3)]Met were also determined in milk protein taken over the last 1h of infusion in HMTBA-infused cows. The infused HMTBA increased whole-body plasma flux of Met by 6.5 mmol/h (from 17.9 to 24.4 mmol/h). Based on enrichments of (13)C-labeled Met, 3.8 mmol/h of Met flow through plasma was derived directly from HMTBA. These 2 estimates accounted for between 43 to 74% of the HMTBA dose infused, contributing to increased whole-body Met availability. Although the portal-drained viscera, liver, and mammary gland (MG) extracted 11, 37, and 3.4%, respectively, of the infused HMTBA, tissue net Met fluxes were either unchanged (portal-drained viscera, MG) or even reduced (liver: -7.9 vs. -2.4±0.6 mmol/h). Therefore, net postsplanchnic supply of Met decreased from 7.0 to 2.9 mmol/h between control and HMTBA-infused cows, compared with needs for milk protein secretion of 7.6 and 8.1 mmol/h, respectively. The HMTBA provided directly 15% of the Met required for milk protein secretion, with 0.2 mmol/h synthesized within the MG, whereas 1.1 mmol/h originated from Met produced in other tissues and transported to the MG through blood circulation. Most of the remainder needed by the MG arose from unlabeled Met released from protein breakdown in extra-splanchnic tissues and that was not reused to support intracellular protein synthesis, as this function was performed by Met synthesized from HMTBA in situ. Absorbed HMTBA, therefore, both produces and spares Met for use by the MG.

SUMMARY Dietary supplementation of trace minerals with a large safety margin is common practice in the poultry industry to prevent trace mineral deficiency. However, oversupplementation of inorganic trace minerals often results in poor bioavailability and low body retention, and can result in more than 90% of the dietary trace minerals being excreted into the environment. In this trial, litter mineral concentrations at the conclusion of the study had very high concentrations of Ca (2.3%), P (1.7%), Cu (150 ppm), Fe (350 ppm), Mn (420 ppm), and Zn (350 ppm). It has been demonstrated that chelated trace minerals are more bioavailable, perhaps because of reduced loss to antagonisms in the intestinal lumen compared with inorganic sources. In 2 commercial broiler trials, performance, meat yield, and footpad health associated with reducing Zn and Mn supplementation while feeding a 50:50 blend of inorganic (sulfates) and chelated forms of Zn, Cu, and Mn were tested. Birds fed the blended treatment exhibited similar or improved growth performance and similar tissue mineral storage compared with those fed the inorganic trace mineral control. In addition, chelated trace minerals improved breast meat yield and footpad health in one trial. In summary, chelated trace minerals are effective alternative trace mineral sources for satisfying the trace mineral needs of rapidly growing broilers and allowing for a reduction in dietary mineral supplementation, thereby potentially reducing the excretion of minerals into the environment.

The objective of the study was to evaluate the effect of diets supplemented with fatty acids of different degrees of saturation, in the absence or presence of an antioxidant (AOX; Agrado Plus, Novus International Inc., St. Charles, MO), on dairy cow lactation performance. Calcium salts of long-chain fatty acids were supplemented as a source of lower saturation fatty acid, and a palm acid product was supplemented as the higher saturation fatty acid source. Sixty early-lactation Chinese Holstein cows (100+/-23 d in milk) were randomly allocated to 4 dietary treatments in a 2 x 2 factorial design: (1) lower saturation fatty acid (LS), (2) LS and AOX, (3) higher saturation fatty acid (HS), and (4) HS and AOX. The Ca salts of long-chain fatty acids and palm acid product were supplied at 1.8 and 1.5% on a dry matter basis, respectively, to form isoenergetic diets. The AOX was added at 0.025% in the ration. The experiment lasted 9 wk, including 1 wk for adaptation. Lactation performance was recorded and milk was sampled and analyzed weekly. Blood samples were taken from the coccygeal vein to determine metabolism parameters on d 16, 36, and 56 during the experiment. Neither fatty acid type nor AOX supplementation showed a significant effect on dry matter intake during the study. Milk yield was lower in the LS-fed cows compared with the cows fed HS. Milk fat and milk protein concentrations were not affected by fatty acid type or AOX supplementation. Adding AOX increased the yield of milk in the LS-fed cows, but did not affect those fed HS. Activity of plasma superoxide dismutase was significantly lower, plasma glucose tended to be lower, and plasma malondialdehyde was higher in the LS-fed animals compared with those fed HS. Addition of AOX decreased both plasma nonesterified fatty acids and hydrogen peroxide contents and increased total antioxidant capacity across the fatty acid types. Plasma beta-hydroxybutyrate was not affected by fatty acid type or AOX treatment. Cows fed LS had higher cis-9C(18:1) and trans-10, cis-12C(18:2) in milk at the expense of C(18:0), whereas AOX addition increased milk cis-9C(18:1) at the expense of milk C(12:0), C(16:0), and trans-10, cis-12C(18:2). It is inferred that feeding LS resulted in inferior lactation performance, whereas addition of antioxidant partially alleviated these negative effects.

Three experiments were conducted to evaluate the effects of feeding 2-hydroxy-4- (methylthio)-butanoic acid (HMTBA) on performance and carcass characteristics of feedlot cattle and on microbial fermentation in a continuous-culture system. In Exp. 1, 160 crossbred steers (initial BW = 385 +/- 10.3 kg) were assigned to 4 treatments consisting of control (0% HMTBA) or 3 diets containing HMTBA (0.069, 0.137, and 0.204%; DM basis) in a randomized complete block design. As the percent of HMTBA increased in the diet, final BW (P = 0.069), final BW adjusted to a constant dressing percent (P = 0.063), and overall ADG (P = 0.099) tended to decrease linearly. Overall DMI decreased linearly (P or = 0.10) were noted for carcass characteristics, except for a tendency (P = 0.078) for a linear increase in the percentage of cattle grading USDA Choice with increasing HMTBA dose. In Exp. 2, 80 crossbred steers (initial BW = 450 +/- 17 kg) in a randomized complete block design were assigned to a control (0% HMTBA) diet or to a diet in which the concentrations of HMTBA were gradually increased from 0.036 to 0.212% of DM over a 50-d period. The HMTBA-containing diet tended to decrease DMI (P = 0.132), but G:F (P = 0.319) for the overall feeding period, carcass measurements, and USDA quality grade (P > or = 0.149) did not differ between treatments. In Exp. 3, continuous culture fermenters (n = 5/treatment) were used to determine the effects of HMTBA (control vs. 0.24% HMTBA) on microbial fermentation. No differences (P > or = 0.31) were detected between treatments in ruminal OM digestibility, microbial N synthesis, pH, ammonia, molar proportions of VFA, or effluent concentration of selected long-chain fatty acids. These results suggest that HMTBA decreased DMI by feedlot steers fed a steam-flaked corn-based diet in a dose-dependent manner; however, gradually increasing the dose over time seemed to moderate effects on DMI. No major changes in microbial fermentation in continuous culture were observed with HMTBA at 0.24% of dietary DM, suggesting effects of HMTBA on DMI were not likely associated with changes in ruminal digestion or fermentation.

The objective of the study was to evaluate the effect of feeding the dietary antioxidant Agrado Plus (AOX; Novus International, St. Louis, MO) in diets that contained 2% fresh fat (FF) or oxidized fat (OF) on milk production and composition and antioxidant status of cows during mid to late lactation. Forty-four mid to late lactating primiparous cows housed in a tie-stall barn were fed a diet that contained 2% FF for 15 d as adaptation period and then randomly allocated to 1 of the 4 dietary treatments (FF, FF+AOX, OF, OF +AOX) for 6 wk. Feeding AOX increased dry matter intake, 3.5% fat-corrected milk, and milk fat yield, and decreased milk protein content but not yield. Feeding OF increased milk fat yield, but decreased dry matter intake and body weight gain. Milk fat composition changed with treatments: AOX increased cis 18:1 and decreased trans-11 18:1, whereas OF decreased trans-9 and trans-11 18:1 and cis-9, trans-11 18:2 in milk. Plasma antioxidant enzymes and status were affected by treatments. Feeding OF increased superoxidase dismutase activity but decreased plasma antioxidant status, whereas AOX supplementation increased glutathione peroxidase activity across fat types and increased the antioxidant status and superoxidase dismutase activity when feeding OF diets. It can be concluded that feeding AOX improved lactation performance and the antioxidant status of the cow across fat types, and feeding OF increased milk fat yield but decreased dry matter intake, body weight gain, and antioxidant status. The negative effects of feeding OF were partially alleviated by AOX.

The objective of this study was to compare the gain-response curve to dietary levels of 2-hydroxy-4(methylthio) butanoic acid (HMTBA) and DL-Met (DLM) across 4 floor pen trials in which different diets were used. Six replicates of 38 or 41 birds per pen (trials 1 to 2 and 3 to 4, respectively) were used in a 2 x 3 factorial arrangement. A control with 12 replicates was also included. The 2 Met sources were fed at 3 equimolar levels equally spaced, with the highest level added at requirements from 1 to 48, 49, 43, or 49 d for trials 1, 2, 3, and 4, respectively. Commercial-type TSAA-deficient control diets contained sorghum, wheat, corn, or corn plus meat and bone meal for trials 1, 2, 3, and 4, respectively. Performance improved at all times for most parameters after supplementing with HMTBA or DLM (P0.05). No differences were found in the birds fed HMTBA or DLM at any age and trial (P0.05), except for trial 1, in which 17-d-old birds performed better when fed HMTBA than DLM (P0.05). In each trial, linear, quadratic, and exponential regressions were conducted upon the gain response of birds fed HMTBA and DLM separately. Equations with better goodness of fit were used to compare the estimated gain responses to feeding HMTBA vs. DLM. In 3 trials, the shape of the gain-response curve differed when feeding HMTBA vs. DLM. In trials 3 and 4, feeding HMTBA at commercial levels resulted in greater gain responses than DLM (P0.05), whereas, in trials 2 and 4, at very deficient levels, DLM-fed birds outperformed those fed HMTBA (P0.05). When the 4 trials were combined, the dose-response curve with the best goodness of fit was linear for HMTBA and quadratic for DLM. It can be concluded that the 2 Met sources have a different dose-response form, HMTBA could outperform DLM at commercial levels, and DLM could outperform HMTBA at deficient levels.

Poultry diets are typically supplemented with DL-2-hydroxy-4(methylthio) butanoic acid (HMTBA, or the hydroxy analog of methionine) or DL-methionine (DLM). Although HMTBA and DLM provide methionine activity, they are structurally distinct molecules with different physiological characteristics until they are converted to L-methionine. The relative rates of intestinal HMTBA vs. DLM absorption have been controversial, and it has been claimed that HMTBA is not fully absorbed. We measured the uptake of HMTBA and DLM in an in vitro everted intestinal slice model. Sections of intestinal slices (jejunum and ileum) were incubated with 0.1 to 50 mM HMTBA that was radiolabeled or DLM that was radiolabeled, and absorption was measured by scintillation counting. The HMTBA uptake was equal to or greater than DLM absorption in each tissue and at every time point with one exception. Furthermore, the rates of HMTBA absorption were always equal to or significantly greater than DLM uptake. In a separate in vivo experiment, absorption of HMTBA and L-methionine was monitored along the entire gastrointestinal (GI) tract. Broilers were fed commercial-type corn-soy diets supplemented with 0.21% HMTBA. Digesta was collected from crop, proventriculus, gizzard, duodenum, jejunum, ileum, large intestine, and cloaca and analyzed for the concentration of free HMTBA and free methionine in each compartment. These studies demonstrated that HMTBA is absorbed completely and along the entire GI tract, especially the upper GI tract. Furthermore, there was a higher concentration of free L-methionine than HMTBA in the digesta from every segment distal to the gizzard.

Controversy about the efficacy of Alimet as a source of methionine arises from the fact that when it is ingested, it is fundamentally different from methionine. Thus, broiler performance studies comparing efficacy of Alimet and DL-methionine (DL-met) continue to be of interest. This report will cover two studies using Alimet Feed Supplement (an 88% aqueous solution of 2-hydroxy-4-(methylthio)butanoic acid, HMTBA). The objective of the first was to compare Alimet with DL-met as sources of supplemental L-methionine (L-met) for broiler production. The sources were fed on an equal dry-matter basis at a level approximating 85% of that used in commercial practice in the UK, where the study was run. A basal diet was used to confirm sensitivity to methionine source addition. No antibiotics were fed. Results confirmed a significant response to supplemental methionine over the 0-42 day study for gain and feed conversion efficiency with no significant difference between Alimet and DL-met. The objective of the second study was to compare performance of Alimet with DL-met when birds were fed high inclusion levels. In this experiment, conducted at Novus International, performance in a basal diet was compared to five supplemental levels of Alimet or DL-met (0.2, 0.5, 1.0, 1.5 and 2.0%). The first level of supplementation was designed to represent an adequate diet with subsequent levels representing excessive addition. Results confirmed that the performance and feed intake of birds fed DL-met was more negatively affected than those fed Alimet, with differences becoming significant above the 0.5% level. Data presented here confirm full molar equivalency of HMTBA to DL-met in broilers fed commercial diets and illustrate the relatively greater safety of Alimet when fed at higher inclusion levels.

To investigate the presence of poly(A) + RNA that encode proteins capable of transporting L-methionine (L-Met) and/or DL-2-hydroxy-4-(methylthio) butanoic acid (HMB), Xenopus oocytes were injected with poly(A) + RNA isolated from broiler intestinal mucosa. Healthy oocytes at stage V or VI were collected from Xenopus laevis and microinjected with water, poly(A) + RNA or size-fractioned poly(A) + RNA. The ability of the injected oocytes to take up either L-Met or HMB was examined by incubating oocytes with [methyl- 3 H]-L-Met or [5- 14 C]-HMB. A greater uptake of L-Met (P < 0.01) and HMB (P < 0.05) by oocytes injected with poly(A) + RNA from the duodenum, jejunum and ileum of the small intestine was observed compared with water-injected oocytes. The greatest (P < 0.05) uptake occurred when poly(A) + RNA from the jejunum or ileum was injected. Injections from four different pools of sucrose gradient-fractionated poly(A) + RNA from all three intestinal segments induced (P < 0.01) L-Met uptake. There were three to four different pools of sucrose gradient-fractionated poly(A) + RNA from the duodenum, jejunum and ileum that induced (P < 0.05) HMB uptake. Uptake of HMB was greater at pH 5.5 than at pH 7.5 and was independent of Na + . Uptake of L-Met induced by all four poly(A) + RNA pools decreased dramatically when Na + was removed from the uptake buffer, which indicated that the majority of L-Met uptake was Na + -dependent. These results indicate that there are multiple sized poly(A) + RNA that encode proteins capable of mediated transport of L-Met and/or HMB present in broiler intestinal mucosa. J. Nutr. 132: 382-386, 2002.

The objective of this research was to determine the efficacy of 2 types of adsorbents [hydrated sodium calcium aluminosilicates (HSCAS) vs. a combination of clay and yeast cell wall] in preventing aflatoxicosis in broilers. A total of 275 one-day-old birds were randomly divided into 11 treatments, with 5 replicate pens per treatment and 5 chicks per pen. The 11 treatments included 3 diets without any adsorbent containing either 0, 1, or 2 mg/kg of aflatoxin B1 (AFB1) plus 8 additional treatments employing 2 dietary levels of AFB1 (1 or 2 mg/kg), 2 different adsorbents [Solis (SO) and MTB-100 (MTB)], and 2 different levels of each absorbent (0.1 and 0.2%) in a 2×2×2 factorial arrangement. Solis is a mixture of different HSCAS and MTB is a combination of clay and yeast cell wall. Feed and water were provided ad libitum throughout the 21-d study period. Body weight gain and feed intake were depressed and relative liver weight was increased in chicks fed AFB1 compared with the positive control (P

Three soybean meal, 3 SoyPlus (West Central Cooperative, Ralston, IA), 5 distillers dried grains with solubles, and 5 fish meal samples were used to evaluate the modified 3-step in vitro procedure (TSP) and the in vitro immobilized digestive enzyme assay (IDEA; Novus International Inc., St. Louis, MO) for estimating digestibility of AA in rumen-undegraded protein (RUP-AA). In a previous experiment, each sample was ruminally incubated in situ for 16 h, and in vivo digestibility of AA in the intact samples and in the rumen-undegraded residues (RUR) was obtained for all samples using the precision-fed cecectomized rooster assay. For the modified TSP, 5 g of RUR was weighed into polyester bags, which were then heat-sealed and placed into Daisy(II) incubator bottles. Samples were incubated in a pepsin/HCl solution followed by incubation in a pancreatin solution. After this incubation, residues remaining in the bags were analyzed for AA, and digestibility of RUP-AA was calculated based on disappearance from the bags. In vitro RUP-AA digestibility estimates obtained with this procedure were highly correlated to in vivo estimates. Corresponding intact feeds were also analyzed via the pepsin/pancreatin steps of the modified TSP. In vitro estimates of AA digestibility of the feeds were highly correlated to in vivo RUP-AA digestibility, which suggests that the feeds may not need to be ruminally incubated before determining RUP-AA digestibility in vitro. The RUR were also analyzed via the IDEA kits. The IDEA values of the RUR were good predictors of RUP-AA digestibility in soybean meal, SoyPlus, and distillers dried grains with solubles, but the IDEA values were not as good predictors of RUP-AA digestibility in fish meal. However, the IDEA values of intact feed samples were also determined and were highly correlated to in vivo RUP-AA digestibility for all feed types, suggesting that the IDEA value of intact feeds may be a better predictor of RUP-AA digestibility than the IDEA value of the RUR. In conclusion, the modified TSP and IDEA kits are good approaches for estimating RUP-AA digestibility in soybean meal products, distillers dried grains with solubles, and fish meal samples.

A dual-effluent continuous culture system was used to investigate, in a 2 x 2 factorial design, the effect of feeding a fresh (FF) or oxidized (OF) blend of unsaturated fats (33% fish oil, 33% corn oil, 26% soybean oil, and 7% inedible tallow) when supplemented with a blend of antioxidants (AO; Agrado Plus, Novus International Inc.; Agrado Plus is a trademark of Novus International Inc. and is registered in the United States and other countries) on nutrient digestibility, bacterial protein synthesis, and fatty acid metabolism. Twice a day for 10 d, 12 fermenters were fed a diet that consisted of 52% forage and 48% grain mixture that contained 3% (dry matter basis) FF or OF, with or without AO. The OF contained a higher concentration of peroxides (215 vs. 3.5 mEq/kg), and a lower concentration of unsaturated fatty acids than the FF. Feeding OF reduced nitrogen digestibility, microbial nitrogen yield, and efficiency (expressed as kilograms of dry matter digested) and increased the outflow of saturated fatty acids in the effluent when compared with feeding FF. Adding AO improved total carbohydrate, neutral, and acid detergent fiber digestibilities and the amount of digested feed nitrogen converted to microbial nitrogen across the types of fats. From this study, we concluded that feeding OF reduced microbial nitrogen and increased the outflow of saturated fatty acids. Feeding AO improved fiber digestibility by rumen microorganisms, regardless of the type of fat.

The objective of this study was to measure net portal absorption of 2-hydroxy-4-methylthiobutanoate (HMTBA) in dairy cows. Four multicatheterized lactating cows were used in a cross-over design with 7-d experimental periods. They were fed every other hour a total mixed ration and received, in addition, twice a day, 12.5 or 25 g/meal of HMTBA. On the last day of treatment, net portal absorption of HMTBA was numerically greater after the 25-g compared with the 12.5-g bolus meal of HMTBA, and the amount absorbed relative to the dose ingested was unchanged between treatments averaging 11.2 +/- 4.7% of the dose. This represents a minimum value of HMTBA availability because it does not take into account any HMTBA metabolized to Met by gut tissues (in sheep this amounted to another 5% of the dose). A rapid method to estimate net portal absorption based on temporal variations of the peripheral plasma HMTBA concentrations following the HMTBA meal is also presented. Based on the good relationship (concordance correlation coefficient = 0.97) observed between direct measurements and estimations, this simplified approach offers a reasonable approach to assess HMTBA absorption under different feeding situations.

The aim of this study was to evaluate effects on nutritional responses of supplemental DL-methionine and 2-hydroxy-4-(methylthio) butanoic acid (HMTBA) in a commercial-type diet in growing dogs. A nitrogen balance study was conducted as a randomized complete block design using 30 Pointer puppies (72-d-old; 5.5 kg). A corn and poultry byproduct meal based diet was supplemented with 0.1 or 0.2% DL-methionine or HMTBA on an equimolar basis. Organic matter and gross energy tended (p < 0.10) to be less digestible by dogs fed the 0.1% HMTBA diet compared with the 0.2% DL-methionine diet, but other nutrients were unaffected. Postprandial urinary calcium tended (p < 0.10) to be lower for the basal and HMTBA treatments. Fecal ammonia tended (p < 0.10) to be lower for the 0.1% HMTBA diet than for the 0.2% DL-methionine diet. At the levels tested, DL-methionine and HMTBA appear to act similarly when included in a corn and poultry by-product meal diet fed to young dogs.

Anabolic availability of the hydroxyl methionine analog, 2-hydroxy-4-methylthiobutanoic acid (HMTBA), given as oral doses to lambs, was quantified both directly as appearance in the portal vein and as synthesis to Met by digestive tract tissues. Eight lambs, prepared with vascular catheters in the mesenteric and portal veins plus the aorta, received twice daily for 7 d either 0.46 g or 2 g of HMTBA. On d 7, [1-13C]HMTBA was supplied as 1 oral dose while [methyl-2H3]Met was infused into the jugular vein. Peak absorption as HMTBA occurred 70 to 90 min after the oral dose. All digestive tract tissues converted HMTBA to Met, equivalent to 24% of the Met provided by the diet for the larger HMTBA dose. Overall, total availability of HMBTA averaged 17.9% of the dose (range 10.6 to 27.9%), with 12.5% (range 7 to 22%) as absorbed HMBTA and the remainder as Met synthesized by digestive tract tissues. Release of 13CO2 into the portal vein accounted for another 23% of the dose. In all digestive tract tissues, the d-isomer was present in a smaller proportion than in the dose. In terms of whole-body kinetics, HMTBA loss from the plasma followed first-order kinetics, with a mean biological half-life of 76 min. Using this value, a simple model was devised to estimate HMTBA absorption based on peripheral plasma samples. When compared with direct measures of absorption, the model gave a slope of 0.81 (R2 = 0.68) and offers a practical means to test HMTBA availability to animals.