Effects of high-sulphur water on hepatic gene expression of steers fed fibre-based diets.

Sulphur-induced polioencephalomalacia (sPEM), a neurological disorder affecting ruminants, is frequently associated with the consumption of high-sulphur (S) water and subsequent poor performance. Currently, there is no economical method for S removal from surface water sources, and alternative water sources are typically neither readily available nor cost-effective. Determination of genes differentially expressed in response to high-S water consumption may provide a better understanding of the physiology corresponding to high dietary S and ultimately lead to the development of treatment and prevention strategies. The objective of this study was to determine changes in gene expression in the liver, an organ important for S metabolism, of fibre-fed steers consuming high-S water. For this study, liver tissues were collected on the final day of a trial from yearling steers randomly assigned to low-S water control (566 mg/kg SO4 ; n = 24), high-S water (3651 mg/kg SO4 ; n = 24) or high-S water plus clinoptilolite supplemented at either 2.5% (n = 24) or 5.0% (n = 24) of diet dry matter (DM). Microarray analyses on randomly selected healthy low-S control (n = 4) and high-S (n = 4; no clinoptilolite) steers using the Affymetrix GeneChip Bovine Genome Array revealed 488 genes upregulated (p < 0.05) and 154 genes downregulated (p < 0.05) in response to the high- vs. low-S water consumption. Real-time RT-PCR confirmed the upregulation (p < 0.10) of seven genes involved in inflammatory response and immune functions. Changes in such genes suggest that ruminant animals administered high-S water may be undergoing an inflammation or immune response, even if signs of sPEM or compromised health are not readily observed. Further study of these, and other affected genes, may deliver new insights into the physiology underlying the response to high dietary S, ultimately leading to the development of treatments for high S-affected ruminant livestock.

Effects of supplemental molybdenum on animal performance, liver copper concentrations, ruminal hydrogen sulfide concentrations, and the appearance of sulfur and molybdenum toxicity in steers receiving fiber-based diets.

Poor performance and S-induced polioencephalomalacia (sPEM) have been observed in ruminant livestock in high-S drinking water regions. No gainful method of removing S from drinking water is available and therefore a feed supplement that negates the effects of high-S water is needed. Our objective was to determine if supplementing Mo improves health and performance of steers administered a high-fiber diet and high-S drinking water. We hypothesized that if the supplemental Mo adequately bound excess S in the rumen, it would not be available at toxic concentrations. Yearling steers (n = 96; 260.0 ± 1.3 kg BW) were stratified by pretrial BW into 12 feedlot pens (n = 8 steers per pen). One of 3 treatments, low-S water (LS; 375 mg SO(4)/L), high-S water (HS; 2,218 mg SO(4)/L), or high-S water plus Mo (HSMO; 2,218 mg SO(4)/L; 187.5 mg Mo/kg DM), were randomly assigned to pens within 4 blocks for a 56-d trial. Body weights were recorded on d -2, -1, 29, 56, and 57, ruminal H(2)S concentrations were measured by rumenocentesis on d -1, 29, and 57, and liver biopsies were performed on d -1 and 57. Performance data were analyzed over the 56-d trial period (overall) as well as over 2 periods: Period 1 (d 0 to d 28) and Period 2 (d 29 to d 56). One case of sPEM was confirmed by the presence of cortical lesions in the HS treatment group. Daily DMI and ADG were affected by treatment and period (P < 0.001) main effects. The LS steers had the greatest (P < 0.05) DMI followed by HS and HSMO steers, respectively. Similar results were observed for ADG. Daily water intake was affected (P < 0.001) by period only, with greater daily water intake in Period 2 than Period 1. Change in hepatic concentrations of Cu, Fe, and Mo over the course of the trial were all affected (P < 0.001) by treatment. Hepatic Cu increased from d 1 to 57 in LS and HS steers but was depleted in HSMO steers. Hepatic Fe and Mo increased in HSMO steers only. Ruminal H(2)S concentrations were affected by treatment (P < 0.021), with greater H(2)S concentrations in HSMO compared with LS and HS steers. Signs of Mo toxicity such as severe diarrhea, loss of body condition, anorexia, changes in hair color, and stiffness in joints were observed in the Mo supplemented steers. These results indicate that added dietary Mo does not adequately bind excess S in the rumen, causing aggravated toxic effects from potentially both the high dietary S and Mo.

Effects of high-sulfur water and clinoptilolite on health and growth performance of steers fed forage-based diets.

Sulfur-induced polioencephalomalacia (sPEM), a neurological disorder affecting ruminants, is associated with consumption of diets with increased S (high-S). High-S water is commonly found in many western states and is a major source of dietary S for grazing cattle. Consumption of high-S water has been associated with sPEM and decreased performance. Identification of a feed supplement that would counteract the negative effects of high-S water would decrease the incidence of sPEM and prevent performance reductions in regions with problematic water sources. The objectives of this study were to 1) determine the effects of administering high-S drinking water to forage-fed feedlot steers on health and performance, and 2) determine the effectiveness of clinoptilolite, a clay mineral with increased cation-exchange capacity, in negating the effects of high-S drinking water. Yearling steers (n = 96; 318.2 +/- 2.1 kg of BW) were randomly assigned to 1 of 4 treatments for a 77-d trial period: control with low-S water (566 mg of SO(4)/L), high-S water (3,651 mg of SO(4)/L), or high-S water plus clinoptilolite supplemented at 2.5 or 5.0% of the diet DM. Feed and water consumption were measured daily, and all steers were weighed on d -2, -1, 29, 53, 76, and 77. Plasma samples were collected on d 0, 58, and 77, and liver samples on d 0 and 77. There was a greater (P or= 0.546) in ADG or G:F were observed. Plasma Cu decreased (P = 0.029) to a greater magnitude in high-S water steers than the control steers over the 77-d trial period. Mineral analyses of hepatic tissue from randomly selected healthy steers from each treatment group (n = 10 per treatment) showed an interaction (P

Synthesis and Mechanical Wear Studies of Ultra Smooth Nanostructured Diamond (USND) Coatings Deposited by Microwave Plasma Chemical Vapor Deposition with He/H(2)/CH(4)/N(2) Mixtures.

Ultra smooth nanostructured diamond (USND) coatings were deposited by microwave plasma chemical vapor deposition (MPCVD) technique using He/H(2)/CH(4)/N(2) gas mixture. The RMS surface roughness as low as 4 nm (2 micron square area) and grain size of 5-6 nm diamond coatings were achieved on medical grade titanium alloy. Previously it was demonstrated that the C(2) species in the plasma is responsible for the production of nanocrystalline diamond coatings in the Ar/H(2)/CH(4) gas mixture. In this work we have found that CN species is responsible for the production of USND coatings in He/H(2)/CH(4)/N(2) plasma. It was found that diamond coatings deposited with higher CN species concentration (normalized by Balmer H(α) line) in the plasma produced smoother and highly nanostructured diamond coatings. The correlation between CN/H(α) ratios with the coating roughness and grain size were also confirmed with different set of gas flows/plasma parameters. It is suggested that the presence of CN species could be responsible for producing nanocrystallinity in the growth of USND coatings using He/H(2)/CH(4)/N(2) gas mixture. The RMS roughness of 4 nm and grain size of 5-6 nm were calculated from the deposited diamond coatings using the gas mixture which produced the highest CN/H(α) species in the plasma. Wear tests were performed on the OrthoPOD(®), a six station pin-on-disk apparatus with ultra-high molecular weight polyethylene (UHMWPE) pins articulating on USND disks and CoCrMo alloy disk. Wear of the UHMWPE was found to be lower for the polyethylene on USND than that of polyethylene on CoCrMo alloy.

Control of mu opioid receptor expression by modification of cDNA 5'- and 3'-noncoding regions.

Removal of a 712 base pair (bp) sequence following the coding region of a human micro opioid receptor (hmuOR) cDNA unexpectedly increased expression of the receptor protein. A series of 3'-noncoding region deletion mutants revealed that at least three discrete regions following the stop codon influenced receptor expression levels. Deletion of the 205-bp 5'-noncoding region immediately preceding the Kozak sequence doubled receptor expression relative to wild type, and simultaneous deletion of 5'- and 3'-noncoding regions increased expression several fold. The hmuOR noncoding regions may participate in a regulatory mechanism that controls the number of cell surface receptors.

A randomized phase II and pharmacokinetic study of dacarbazine in patients with recurrent glioma.

We conducted a randomized phase II study to determine the efficacy of dacarbazine (DTIC) in recurrent gliomas. Patients were randomly assigned to receive either DTIC 750 mg/m2 IV day 1 every 28 days (Arm A) or DTIC 200 mg/m2 IV days 1-5 every 28 days (Arm B). Pharmacokinetics were studied in 6 patients on each arm using HPLC analysis. Thirty-nine patients (30 male, 9 female), ages 27-67 years (median 53) were entered on the study (20 on Arm A, 19 on Arm B). No objective responses were seen. Median time to progression was 3 months. Median survival was 8 months. Treatment was generally well tolerated. Major toxicities were grade 1-2 nausea (33%). lethargy (28%), diarrhea (15%), alopecia (15%), and grade 3 neutropenia (8%). Four patients on Arm A had mild self-limited episodes of intravascular hemolysis occurring immediately after drug infusion, the mechanism of which is unknown. Mean AUC for DTIC, HMMTIC (5-[3-hydroxymethyl-3-methyl-1-triazeno] imidazole-4-carboxamide), and MTIC (5-[3-methyl-1-triazenol imidazole-4-carboxamide), in Arm A were 14.8, 0.17, and 1.15 mM min, respectively. Corresponding values for Arm B (on day 1 of 5) were 1.7, 0.06, and 0.29 mM min, respectively. The predicted HMMTIC and MTIC exposure over 5 days for Arm B, based on the day 1 data, is higher than with Arm A. We conclude that DTIC is well tolerated but does not have activity in patients with recurrent gliomas. The 5-day schedule appears less toxic, and pharmacokinetic studies show that it provides greater exposure to MTIC and HMMTIC compared to the one-day schedule.

Mutation of human mu opioid receptor extracellular "disulfide cysteine" residues alters ligand binding but does not prevent receptor targeting to the cell plasma membrane.

The mu opioid receptor, a primary site of action in the brain for opioid neuropeptides and opiate drugs of abuse, is a member of the seven transmembrane, G protein-coupled receptor (GPCR) superfamily. Two cysteine residues, one in each of the first two of three extracellular loops (ECLs), are highly conserved among GPCRs, and there is direct or circumstantial evidence that the residues form a disulfide bond in many of these receptors. Such a bond would dramatically govern the topology of the ECLs, and possibly affect the position of the membrane-spanning domains. Recent findings from several laboratories indicate the importance of the ECLs for opioid ligand selectivity. These conserved cysteine residues in the mu opioid receptor were studied using site-directed mutagenesis. Little or no specific binding of radiolabled opiate alkaloid or opioid peptide agonists or antagonists was observed for receptors mutated at either "disulfide cysteine" residue. Each mutant mu opioid receptor was expressed in both transiently- and stably-transfected cells, in some cases at levels comparable to the wild type receptor. The two point mutants possessing serine-for-cysteine substitutions were also observed to successfully reach the cell plasma membrane, as evidenced by electron microscopy. Consistent with related work with other GPCRs, the mu opioid receptor apparently also employs the extracellular disulfide bond. This information now permits accurate molecular modeling of extracellular aspects of the receptor, including plausible scenarios of mu receptor docking of opioid ligands known to require specific extracellular loop features for high affinity binding.

Evaluation of wheat middlings as a supplement for beef cows grazing native winter range with differing forage availabilities.

We conducted two studies to compare wheat middlings as a low-protein, highly digestible fiber supplement to soybean meal and corn-soybean meal supplement for cows grazing winter range. In two 60-d winter grazing trials (December to February) cows (BW 500 kg) were allotted by age and weight to a 2 x 4 factorial with two forage availabilities and four supplements. Cows received either soybean meal (SBM), corn-soybean meal (CS), low wheat middlings (LWM), or high wheat middlings (HWM). The SBM and LWM supplements were formulated to provide the same daily CP, and CS and HWM provided the same daily CP and ME. In a 4 x 4 Latin square, four ruminally fistulated steers (BW 765 kg) received the same supplements and had free access to mature prairie hay. Cows grazing the high forage pasture gained more (P < .01) weight than cows grazing the low forage pasture. Cows supplemented with HWM gained less weight (P = .05) than cows supplemented with a similar amount of CP and ME from CS. Weight change of cows receiving SBM or LWM was similar. Increasing the amount of wheat middlings from LWM to HWM increased weight change (P = .04). In Exp. 2, SBM and LWM had similar total digestible DMI (DDMI). Steers supplemented with CS had higher total (P = .08) DDMI than HWM. Supplementation with HWM resulted in lower total (P = .02) DDMI than LWM. Response to SBM and LWM was similar. The CS and HWM resulted in beneficial performance responses as well as increasing the level of wheat middlings from low to high.

Cloning of a brain N-methyl-D-aspartate- and D, L-epsilon-2-amino-4-propyl-5-phosphono-3-pentanoic acid (CGP 39653)-binding protein.

A complex of four proteins isolated from neuronal membranes has ligand binding sites for N-methyl-d-aspartate (NMDA) receptor agonists and antagonists and forms NMDA-activated ion channels upon reconstitution into lipid membranes. In this study, the cDNA of a subunit of this complex containing binding sites for the competitive antagonists of NMDA receptors was cloned. The cDNA clone coded for a protein of 719 amino acids (78.9 kDa). The expressed protein had binding activity for the agonists l-[3H]glutamate and [3H]glycine, the antagonist (+/-)-[3H]-(E)-2-amino-4-propyl-5-phosphonopentanoic acid ([3H]CGP 39653), but not the ion channel inhibitors. The cloned cDNA had no homology to other cloned cDNAs. Northern blot analyses indicated high expression of an 3.8 kb poly(A+) RNA in brain, but not in other tissues. These findings indicate that proteins that have recognition sites for NMDA receptor activators and inhibitors and that differ from the well-characterized NMDA receptor proteins NR1-3 are expressed in mammalian brain.

Granulocyte colony-stimulating factor in severe chemotherapy-induced afebrile neutropenia.

BACKGROUND: Randomized trials of colony-stimulating factors in febrile patients with neutropenia after chemotherapy have not consistently shown clinical benefit. Nevertheless, the use of colony-stimulating factors to treat patients with chemotherapy-induced neutropenia is widespread. METHODS: We performed a randomized, double-blind, placebo-controlled trial of granulocyte colony-stimulating factor (G-CSF) in afebrile outpatients with severe chemotherapy-induced neutropenia. We measured the number of days of neutropenia, rate of hospitalization, number of days in the hospital, number of days the patient received parenteral antibiotics, and number of culture-positive infections. RESULTS: We randomly assigned 138 patients to receive G-CSF (n=71) or placebo (n=67). The median time to an absolute neutrophil count of at least 500 per cubic millimeter was significantly shorter for patients who received G-CSF (two days, vs. four days for the patients given placebo). However, there was no effect on the rate of hospitalization, number of days in the hospital, duration of treatment with parenteral antibiotics, or number of culture-positive infections. CONCLUSIONS: Routine therapeutic application of G-CSF in afebrile patients with severe neutropenia can reduce the duration of neutropenia, but this does not appear to provide practical clinical benefit.

Cloning of the cDNA for a brain glycine-, glutamate- and thienylcyclohexylpiperidine-binding protein.

Polyclonal antibodies (Ab's) were raised against a 43-kDa component of a protein complex that has ligand recognition sites similar to those of brain N-methyl-D-aspartate (NMDA) receptors. The Ab's were used to immunopurify from brain synaptic membranes a 60-kDa glycine (Gly), glutamate (Glu) and thienylcyclohexylpiperidine (TCP)-binding protein and to screen a rat hippocampal cDNA expression library. A 1.85-kb clone, pGlyBP, coding for a protein of 470 amino acids (52.7 kDa) was identified. Northern blot analyses performed on poly(A+) RNA from brain revealed hybridization of the labeled cDNA probes to transcripts of 1.9 kb. E. coli transformed with the pGyBP expressed a protein that was recognized by the anti-43 kDa Ab's and had recognition sites for Gly, Glu and TCP. The cloned protein has 2 glycosylation sites, 3 hydrophobic domains, 4 cysteine-rich motifs (C-X2-C-X16-20-C-X5-11), and 2 regions homologous to the NR1 receptor protein.

Neurotransmitter transporters: three important gene families for neuronal function.

Three distinct gene families encode transporter proteins that aid in temporal and spatial buffering of neurotransmitter and neurotransmitter metabolite concentrations and allow neurons to cycle and recycle transmitter molecules. Analyses of these gene families and their products are likely to enhance understanding of the molecular neurobiology of neuronal function and may elucidate contributors to the genetic etiologies of neurological and psychiatric disease.

Purification and pharmacological and immunochemical characterization of synaptic membrane proteins with ligand-binding properties of N-methyl-D-aspartate receptors.

A method was developed for the solubilization of approximately 50% of proteins in synaptic membranes that have ligand-binding characteristics of N-methyl-D-aspartate (NMDA) receptors. Affinity chromatographic separation of the solubilized proteins through L-glutamate-derivatized matrices and subsequent elution by NMDA-containing buffers led to the purification of four predominant proteins with estimated sizes of 67-70, 53-62, 41-43, and 28-36 kDa. The co-purification of NMDA-sensitive L-glutamate binding, dizocilpine-sensitive thienylcyclohexyl piperidine (TCP)-binding, and strychnine-insensitive glycine-binding proteins was achieved by this affinity chromatographic procedure. Glutamate, glycine, and the polyamine spermidine increased both the "on" rate and the equilibrium level of [3H]TCP binding to the isolated proteins. The group of proteins eluted by NMDA from the glutamate-derivatized matrices could be further purified through size exclusion chromatography of the NMDA-sensitive glutamate-binding from the dizocilpine-sensitive TCP-binding proteins. Polyclonal and monoclonal antibodies to the cloned NMDA receptor protein NMDAR1 did not react with any proteins in the solubilized membrane proteins or the purified fractions. However, immunoreaction of antibodies raised against a glutamate-binding protein and a phosphonoaminocarboxylic acid-binding protein indicated that these are two of the major proteins in the purified fractions. These studies indicate that these two proteins might be components of a complex that has some of the characteristics of NMDA receptors and that neuronal membranes may contain varieties of NMDA-like receptors composed of protein subunits that differ from the NMDAR1 and NMDAR2 receptor proteins.

Human kappa opiate receptor second extracellular loop elevates dynorphin's affinity for human mu/kappa chimeras.

To investigate roles of second extracellular loop sequences in peptide and nonpeptide ligand recognition by human opiate receptors, we have constructed a chimeric receptor in which this domain of the human mu opiate receptor has been replaced with that of the human kappa opiate receptor. The chimeric opiate receptor displays dramatically increased affinity for dynorphin peptides. Affinities for dynorphin A-(1-17), dynorphin A-(1-13), and alpha-neoendorphin increase by up to 250-fold when compared with the wild-type human mu opiate receptor. The chimera maintains recognition of the mu-selective ligands morphine and [D-Ala2,MePhe4,Gly-ol5]enkephalin and displays no significant changes in affinity for the kappa-selective small molecule ligand U50,488. The chimeric opiate receptor displays evidence for effective G-protein coupling; 100 nM dynorphin A-(1-17) is as effective as 100 nM morphine at inhibiting forskolin-stimulated adenyl cyclase activity through actions at the chimeric receptor. These data suggest that the putative second extracellular loop contributes substantially to the kappa receptor's selectivity in dynorphin ligand recognition.

-mu opiate receptor. Charged transmembrane domain amino acids are critical for agonist recognition and intrinsic activity.

The mu opiate receptor is a principal brain site for activities of morphine, other opiate drugs, and opioid peptides in modulating pain and altering mood. Recent cloning of cDNAs encoding rat and human mu receptors reveals charged amino acid residues within putative transmembrane domains (TMs) II, III, and VI, a substantial N-terminal extracellular domain, and a C-terminal intracellular domain. Deletion of 64 N-terminal amino acids produced little effect on receptor function (Wang, J.B., Imai, Y., Eppler, C.M., Gregor, P., Spivak, C.E., and Uhl, G.R. (1993) Proc. Natl. Acad. Sci. U.S.A. 90, 10230-10234). Further deletion of 33 C-terminal amino acids yielded a receptor at which morphine, but not the substituted enkephalin DAMGO ([D-Ala2,MePhe4,Glyol5]enkephalin), inhibited adenylate cyclase. Alanine substitution for each charged TM residue in the N-terminally deleted receptor reduced affinities for morphine, DAMGO, and the opiate antagonist naloxone. Replacement of TM II Asp114 with asparagine or glutamic acid increased mu receptor affinity for naloxone. TM II and TM III glutamic acid substitutions for Asp114 and Asp147 reduced agonist binding affinities but allowed full inhibition of adenylate cyclase at high agonist concentrations. TM VI histidine substitution with alanine yielded a receptor that produced almost twice the cyclase inhibition displayed by the wild type receptor in parallel transient expression assays. These findings underscore the importance of charged residues in TM II, III, and VI for different receptor functions and the modest involvement of extensive portions of N- and C-terminal receptor domains in these processes.

cDNA cloning of an orphan opiate receptor gene family member and its splice variant.

Radioligand binding and cDNA homology studies have suggested the existence of opiate receptors distinct from the recently-cloned mu, delta and kappa receptors. XOR1S, a rat brain cDNA whose predicted translation product displays 67-72% homology with those encoded by mu 1, delta 1 and kappa 1 opiate receptor cDNAs, was constructed from two partial cDNAs identified through cDNA homology approaches. A longer XOR1L variant of this cDNA was also identified by polymerase chain reaction studies using genomic DNA and cDNA from brain and peripheral tissues. XOR1 mRNA is most highly expressed in hypothalamus. COS cell expression of both clones confers neither robust binding of opiate ligands nor reproducible opiate inhibition of forskolin-stimulated adenylate cyclase. These studies identify an orphan clone that helps to define features of the opiate receptor gene family, including apparent differential splicing and expression in peripheral tissues.

Expressed mu opiate receptor couples to adenylate cyclase and phosphatidyl inositol turnover.

The recently cloned rat mu opiate receptor cDNA has been expressed in COS and Chinese hamster ovary (CHO) cells to examine the coupling of this receptor to G-protein linked second messenger systems and examine possible coupling to multiple second messenger systems. Morphine (1 microM) reduced both forskolin-stimulated cAMP levels and IP3 levels by 20 +/- 5 and 34 +/- 8% respectively in COS and CHO cell cultures expressing the cloned rat mu receptor cDNA. Both effects could be blocked by naloxone and Gpp(NH)p. These results represent the first clear representation of the second messenger system promiscuity possible with a single cloned opiate receptor.

Human mu opiate receptor. cDNA and genomic clones, pharmacologic characterization and chromosomal assignment.

A human mu opiate receptor cDNA has been identified from a cerebral cortical cDNA library using sequences from the rat mu opiate receptor cDNA. The human mu opiate receptor (h mu OR1) shares 95% amino acid identity with the rat sequence. The expressed mu OR1 recognized tested opiate drugs and opioid peptides in a sodium- and GTP-sensitive fashion with affinities virtually identical to those displayed by the rat mu opiate receptor. Effects on cyclic AMP are similar to those noted for the rat mu opiate receptor. An 18 kb genomic clone hybridizing with the h mu OR1 cDNA contains 63 and 489 bp exonic sequences flanked by splice donor/acceptor sequences. Analysis of hybridization to DNA prepared from human rodent hybrid cell lines and chromosomal in situ hybridization studies indicate localization to 6q24-25. An MspI polymorphism, producing a 3.7 kb band, may prove useful in assessing this gene's involvement in neuropsychiatric disorders involving opiatergic systems.

Effect of methionine addition to a urea-grain supplement on intake and digestibility of mature, dormant grasses and performance of cows grazing winter range.

A digestibility trial involving 20 Hampshire ram lambs and a 2-yr grazing study using 103 mature crossbred cows were conducted to determine the effects of methionine addition to a urea-grain supplement on intake and digestibility of dormant range grasses and on cow performance. In each trial, four treatment groups were supplemented with either a urea-grain control (CON), urea-grain plus methionine (MET, 3.3% DL-methionine), urea-grain plus inorganic sulfur (SUL, 3.0% sodium sulfate), or soybean meal (SBM). Supplements were designed to provide 45 and 360 g of CP.animal-1.d-1 (lambs and cows, respectively) and were balanced for ME, Ca, P, and K. Lambs had ad libitum access to mature prairie hay, whereas cows grazed dormant winter range from mid-November until mid-February. For the grazing study, forage OM intake (OMI) was determined in late November and in late January by the fecal output/indigestibility ratio technique. Controlled-release chromic oxide boluses were used as an external marker to estimate fecal output, and acid insoluble ash was used as an internal marker to predict OM digestibility (OMD). Mean daily DMI of mature prairie hay was 1,057 g/lamb and was not affected by supplementation. Apparent DM, NDF, and ADF digestibilities and N biological value did not differ (P > .10) among treatments. Nitrogen digestibility was increased (P = .06) for lambs fed the MET or SUL compared with CON.(ABSTRACT TRUNCATED AT 250 WORDS)