Establishment of reference values for the lysine acetylation marker Nɛ-acetyllysine in small volume human plasma samples by a multi-target LC-MS/MS method.

Cardiovascular disease (CVD) and chronic kidney disease (CKD) constitute substantial burdens for public health. The identification and validation of risk markers for CVD and CKD in epidemiological studies requires frequent adaption of existing analytical methods as well as development of new methods. In this study, an analytical procedure to simultaneously quantify ten endogenous biomarkers for CVD and CKD is described. An easy-to-handle sample preparation requiring only 20 µL of human plasma is followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The method was successfully validated according to established guidelines meeting required criteria for accuracy, precision, recovery, linearity, selectivity, and limits of quantification. The scalability of the method for application in larger cohorts was assessed using a set of plasma samples from healthy volunteers (n = 391) providing first reference values for the recently established biomarker Nɛ-acetyllysine (Nɛ-AcLys). Other biomarkers analyzed were creatinine, ß-aminoisobutyric acid (ß-AIB), carnitine, 1-methylnicotinamide (1-MNA), citrulline, symmetric dimethylarginine (SDMA), asymmetric dimethylarginine (ADMA), homoarginine (hArg), and ornithine. All obtained results are within reference values specified elsewhere. Overall, these results demonstrate the suitability of the method for simultaneous quantification of ten endogenous biomarkers for CVD and CKD in plasma samples from larger cohorts and allow validation of Nɛ-AcLys as a biomarker in large cohorts.

Steroids and L-Lysine Aescinate for Acute Radiculopathy Due to a Herniated Lumbar Disk.

BACKGROUND AND OBJECTIVES: The efficacy of commonly prescribed analgesic and adjuvant drugs for the management of patients with radiculopathy has not been well established. Oral steroids are commonly used to treat sciatica or radiculopathy due to a herniated disk but the effect remains controversial. L-lysine aescinate showed superiority over placebo or baseline therapy with NSAIDs alone in treating sciatica, but have not been evaluated in an appropriately powered clinical trial. MATERIALS AND METHODS: Randomized, double-blind clinical trial conducted in two health centers in collaboration with Uzhhorod Natioanl University in Ukraine. Adults (N = 90) with acute radicular pain and a herniated disk confirmed by MRI were eligible. Participants were randomly assigned to three groups (N = 30 in each) to receive a baseline therapy with lornoxicam (16 mg per day) and adjunctive 5-day course of IV dexamethasone (first group: 8 mg per day/40 mg total) or 0,1% solution of L-lysine aescinate (5 mL and 10 mL for group 2 and 3 respectively). Primary outcomes were Visual Analogue Scale changes and the straight leg raise angle at 15th and 30th day. RESULTS: The level of pain improvement at 15th days after initiation of therapy with dexamethasone or solution of L-lysine aescinate at doses of 5 or 10 mL was not significantly different. The lowest levels of pain were achieved in patients who received the L-lysine aescinate 10 mL, but the range of decrease in pain was slightly greater in the group administered dexamethasone. CONCLUSIONS: Among patients with acute radiculopathy due to a herniated lumbar disk a short course of IV dexamethasone or L-lysine aescinate resulted in pain improvement at 15th and 30th day. Dexamethasone may be preferable if a longer-term analgesic effect is needed. Taking into account side effects of dexamethasone, a solution of L-lysine aescinate can be used to relieve pain symptoms.

Particulate Study on NeoProfen, a Neonatal Injectable Product.

UNLABELLED: NeoProfen or sterile ibuprofen L-lysine at 10 mg/mL ibuprofen, in 2 mL single-use Type I glass vials is often a first choice medication used to close a patent ductus arteriosus in neonatal patients from 500 to 1500 g body weight. Visible particulate matter was found in vials that were placed on a commercial stability program prior to the approved expiration date of 2 years. A combination of instrumental techniques including inductively coupled plasma-mass spectrometry, x-ray photoelectron spectroscopy, scanning electron microscopy energy dispersive x-ray spectrometry, and Raman and Fourier transform infrared microspectroscopy was used to evaluate stability, pilot batch and packaging samples in a root cause investigation. The particulate matter was shown to consist largely of ibuprofen aluminum salts of various stoichiometries. It developed over time by a substitution mechanism, in which the ibuprofen anion in solution reacts with the aluminum oxide network of the borosilicate glass giving the ibuprofen aluminum salt with =Al-OH remaining in the network. For corrective action an alternate Type I borosilicate glass vial with interior coating, not found in the original vial, was chosen for the product to prevent this occurrence. LAY ABSTRACT: NeoProfen (sterile preservative-free ibuprofin L-lysine at 17 mg/mL in a single-use glass vial) is used to close a clinically significant patent ductus arteriosus in premature infants no more than 32 weeks gestational age. The neonatal population is especially sensitive to outside chemical, physical and environmental conditions because of incompletely developed organ systems, low birth weight and other underlying conditions. Two batches of this product were voluntarily recalled by the manufacturer, Lundbeck, and investigated for the source of particulate matter observed during a commercial stability testing program. This was found to result from an interaction between the product and the Type I borosilicate glass vial where ibuprofen substitutes for the aluminum oxide network in the glass, forming an ibuprofen aluminum hydroxide salt as particulate. In order to prevent this salt formation an alternate glass vial was chosen which had interiors treated using a chemical vapor deposition technique. These vials were found to preserve NeoProfen quality properties during short term stress and medium term stability studies.

Lysine requirement of adult males is not affected by decreasing dietary protein.

Recently, we reported the lysine requirement to be 41.2 mg.kg-1.d-1 using indicator amino acid oxidation (IAAO) in healthy adult males fed a protein intake of 1.0 g.kg-1.d-1. A lower protein intake has been hypothesized to significantly lower the requirement estimate. We tested this hypothesis using IAAO by estimating the lysine requirement at a protein intake of 0.8 g.kg-1.d-1 in five healthy adult males. Lysine requirement was determined from the rate of appearance of 13CO2 in breath (F13CO2) by using a primed 4-h continuous infusion of L-[1-(13)C]phenylalanine. Phenylalanine flux was not affected by graded increases in dietary lysine. Phenylalanine oxidation and F13CO2 decreased linearly (P < 0.05) as lysine intake increased to a breakpoint, after which the rates were not significantly different. Two-phase linear regression determined this breakpoint (mean lysine requirement) to occur at a dietary lysine intake of 45.0 mg.kg-1.d-1. We conclude that no reduction appears in the lysine requirement with a lower protein intake. Thus, lysine requirement appears not to be altered by protein intakes within the lower end of the protein requirement range.

Interactive effects of feed intake and stage of growth on the lysine requirement of pigs.

We studied the effect of reduced feed intake on the lysine requirement of pigs at the early growing (G) and finishing (F) phases. Two sets of 40 individually penned crossbred barrows averaging 27.1 +/- .2 (G) and 92.6 +/- 1.1 kg BW (F) were fed five dietary treatments (G; .75, .90, 1.05, 1.20, 1.35%; and F: .45, .60, .75, .90, 1.05% lysine) at two feeding levels (equivalents to 100 and 80% ad libitum intakes) for 15 d. In both stages pigs on the 80% feeding level had lower ADG (P < 0.01) and lower plasma urea nitrogen (PUN) concentrations (P < .10) than pigs on the 100% feeding level. In all instances, increasing dietary lysine caused ADG to increase (P < .05) and PUN to decrease (P < .10) linearly. A tendency for an interaction was detected between the effects of growth stage and the effects of feeding level on the lysine requirements estimated by ADG (P < .19) and PUN (P < .10). In the F stage, pigs on the 80% feeding level required a greater dietary lysine concentration to maximize ADG and minimize PUN (.85 and .87%, respectively) than pigs on the 100% feeding level (.61 and .68%, respectively). In the G stage, however, the dietary lysine concentrations required to maximize ADG (.97 to 1.01%) and minimize PUN (1.05 to 1.09%) were not different (P > .20) between feeding levels. We conclude that the effect of a reduction in feed intake on the lysine requirement depends on the stage of growth of the pigs.

Ratio of total sulfur amino acids to lysine for finishing pigs.

We conducted two experiments to determine the optimum ratio of total sulfur amino acids (TSAA) to Lys for late finishing pigs. In Exp. 1, 50 barrows and 50 gilts were allotted to treatments with three replicates of three or four pigs per replicate in a randomized complete block (RCB) design within a split-plot arrangement of treatments. Sex was the whole plot and TSAA:Lys ratio was the subplot. Average initial and final BW were 77 and 111 kg. Barrows and gilts were fed diets formulated to contain .55 and .65% Lys, respectively. The ratios of TSAA:Lys were .50, .55, .60, .65, and .70. Diets met or exceeded an ideal amino acid pattern for all indispensable amino acids (except TSAA), and all diets were isonitrogenous and equal in electrolyte balance. In Exp. 2, 60 gilts were allotted to five treatments with four replicates of three gilts each in a RCB design. Average initial and final BW were 74 and 110 kg. Gilts were fed diets formulated to contain .65% Lys. The ratios of TSAA:Lys were .35, .425, .50, .575, and .65. In Exp. 1, there were no TSAA:Lys ratio effects (P > .10) for ADG, final BW, percentage muscle, longissimus muscle area, carcass length, percentage fat-free lean (PFFLEAN), lean gain per day (LGD), total fat (TOFAT), percentage TOFAT (PTOFAT), fat gain per day (FGD), lean:fat, retained energy in TOFAT as ether extractable lipid (RE-F), retained energy (RE), or serum urea N (SUN). Feed intake (ADFI) was greater (quadratic, P < .05) for pigs fed .70 TSAA:Lys than for pigs fed any other treatment. Hot carcass weight, psoas muscle weight, 10th rib fat thickness, dressing percentage, fat-free lean (FFLEAN), and retained energy in FFLEAN as protein (RE-P) responded inconsistently to TSAA:Lys ratio, resulting in cubic (P < .09) effects. In Exp. 2, ADFI (linear, P < .08), TOFAT (linear, P < .05), PTOFAT (linear, P < .07), FGD (linear, P < .05), RE-F (linear, P < .05), RE (linear, P < .05), and SUN (linear, P < .02; quadratic, P < .01) decreased as TSAA:Lys ratio increased. Also, gain:feed (GF) (linear, P < .01; quadratic, P < .04), PFFLEAN (linear, P < .04), and lean:fat (linear, P < .04) increased as TSAA:Lys ratio increased. One-slope, broken-line regression models estimated required ratios of TSAA:Lys of .44 (SUN), .40 (ADG), .47 (ADFI), .45 (GF), .45 (FFLEAN), .44 (LGD), .65 (TOFAT), .65 (FGD), .44 (RE-P), .65 (RE-F), .65 (RE), and .57 (lean:fat). Thus, for growth and muscling traits of late finishing pigs, the optimum ratio of TSAA:Lys is less than the current proposed ratio (.65), but to minimize fat accretion, the ratio is .65.

The lysine requirement of lactating primiparous sows.

We conducted an experiment with 289 primiparous sows to evaluate the effect of lysine intake on lactation and subsequent reproductive performance. Sows were randomly allotted to one of five experimental corn-soybean meal lactation diets. The first four diets contained incremental levels of apparently digestible lysine (.67, .86, 1.06, and 1.25%) and provided digestible lysine intakes of 27, 34, 41, and 48 g/d. All lysine was derived from intact protein sources. Synthetic valine, threonine, and methionine were used to maintain ratios to lysine that were equal to those of the .67% lysine diet. The fifth diet contained 1.06% digestible lysine and provided 43 g/d digestible lysine, but no additional synthetic amino acids were added. The average lactation length in this study was 16.9 +/- .2 d. Lysine intake during lactation did not affect number of pigs weaned, litter growth rate, sow backfat loss, or weaning to mating interval. Sow weight loss and loin eye area loss decreased quadratically (P < .05) with increasing lysine intake. These were minimized at 45 and 48 g/d digestible lysine, respectively. Removing synthetic amino acids from the 1.06% digestible lysine diet resulted in an increased litter growth rate (1.98 vs 2.15 kg/d, P < .05). Increasing dietary lysine intake while maintaining amino acid ratios to lysine for valine, threonine, and total sulfur amino acids during the first lactation resulted in a linear (P < .05) decrease in second litter total born. However, removal of synthetic amino acids from the 1.06% digestible lysine diet resulted in an increased second litter total born (12.9 vs 11.2, P < .05), which tended to be higher compared with the .67% digestible lysine treatment (12.9 vs 11.7, P = .13). The results suggest that primiparous sows are able to mobilize sufficient body reserves to maintain a high level of milk production at low levels of lysine intake during a 17-d lactation. Higher levels (45 to 48 g/d) of digestible lysine are required to minimize body protein loss. The source or composition of amino acids in the lactation diet may have an effect on second litter size.

Interaction of diet composition and a reduced nocturnal temperature regimen in weanling pigs.

A three-trial experiment using 3- to 4-wk-old newly weaned pigs was conducted to evaluate the possible interaction between a 16-h reduced nocturnal temperature regimen (RNT16) and a lowered nursery diet lysine regimen on weaned pig and subsequent growing-finishing performance. Nursery temperature treatments were 1) a control temperature (CT) regimen of 30 degrees C constant air temperature lowered 2 C degree/wk and 2) a regimen beginning 1 wk after weaning in which the temperature from 1600 to 0800 was lowered 6 C degree from CT. Within each temperature treatment, all pigs were offered a diet containing 1.20% lysine for the 1st wk after weaning followed by 1.20 or 1.10% lysine to 10.5 kg and 1.00 or .90% lysine to 20 kg. There was no interaction of temperature regimen and diet on overall nursery performance. The RNT16 pigs had improved (P = .1) ADG (.351 vs .342 kg/d) with no difference (P > .1) in ADFI (.693 vs .680 kg/d) or G:F (.508 vs .506) compared with CT. Pigs fed the lower lysine sequence had poorer (P < .0001) ADG (.333 vs .360 kg/d) and G:F (.487 vs .527) than controls. There was also no effect (P > .1) of RNT16 vs CT on subsequent performance to slaughter weight for ADG (.770 vs .755 kg/d) or G:F (.309 vs .311). There was also no effect (P > .1) of a lowered nursery lysine sequence compared to control on growing-finishing ADG (.768 vs .757 kg/d) or G:F (.312 vs .309).(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of a copper-lysine complex as a growth promotant for weanling pigs.

Eight 28- or 35-d experiments involving, 1,301 crossbred pigs weaned at 30 +/- 2 d of age (7.0 to 7.9 kg initial weight) were conducted to evaluate the efficacy of a Cu-lysine complex (CuLys; CuPLEX 80 in Exp. 1 to 5, and CuPLEX 100 in Exp. 6 to 8) at dietary concentrations of 50, 100, or 200 ppm as a growth promoter for weanling pigs. CuPLEX 80 contained 50% Cu in the complexed from (1 mol Cu:2 mol lysine) and 50% Cu as CuSO4.5H2O (CuSO4). All the Cu in CuPLEX 100 was in the complexed form. In general, the addition of Cu from CuSO4 or either CuLys source improved pig performance. Overall, averaged across Cu sources, there were no differences between 100 and 200 ppm of Cu in the magnitude of improvement over controls for daily gain (14.0 vs 14.3%), daily feed (12.1 vs 10.7%), or feed:gain ratio (1.6 vs 3.0%). Averaged across levels of Cu supplementation, the percentage improvements from CuLys additions were greater than those for CuSO4 for growth rate (16.8 vs 11.5%; P < .03) and feed intake (14.1 vs 8.7%' P < .01), but not for efficiency of feed utilization (2.2 vs 2.4%). These trends were similar for both sources of CuLys. Liver Cu concentrations of pigs receiving 200 ppm of Cu in the totally complexed form (CuPLEX-100) were lower (P < .025) than concentrations in those receiving 200 ppm of Cu from CuSO4 (111 vs 221 ppm).(ABSTRACT TRUNCATED AT 250 WORDS)

High-lysine corn as a source of protein and energy for finishing calves.

Three trials evaluated the protein and energy value of high-lysine corn for finishing calves. In Trial 1, 60 finishing steer calves were used to evaluate corn source (high-lysine vs control) and protein source (urea, blood meal [BM], corn gluten meal [CGM]) and level (BM and CGM addition; low, medium, high). Calves were individually fed using Calan gates for 102 d, and then were pen-fed (two pens per corn treatment) the remaining 83 d. During the initial 102 d, calves fed high-lysine corn had similar gains but were 6% more efficient (P < .10) compared with calves fed control corn. Performance did not differ (P > .10) among sources or levels of protein supplementation. Over the entire feeding period (185 d), calves fed high-lysine corn were 10% more efficient (P < .10) than calves fed control corn. In the second study, in situ starch disappearance was faster (P < .10) and the proportion of CP degraded by 12 h was 27% greater (P < .10) for high-lysine corn than for control corn. In a metabolism trial, five steers fitted with ruminal, duodenal, and ileal cannulas were used in a randomized block design to evaluate the effect of corn source on site and extent of digestion. Intake and ruminal and total tract digestibility of OM and N did not differ (P > .10) between corn sources. Steers fed high-lysine corn tended to have greater ruminal (P = .23) and postruminal (P = .18) starch digestion, resulting in greater (P < .10) total tract starch digestibility.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect on performance and carcass characteristics of nursery to finisher pigs fed reduced crude protein, amino acid-supplemented diets.

An experiment was conducted to evaluate the effect of feeding reduced CP, amino acid (AA)-supplemented diets to pigs from weaning to slaughter weight on growth performance and carcass characteristics. Pigs were fed a 19%-16%-14% CP starter-grower-finisher high-CP sequence of diets, respectively, or a sequence of diets reduced in CP by 4 percentage units (3 percentage units in the finisher period) with or without lysine (LYS), tryptophan (TRP), and threonine (THR) supplementation. Pigs fed the low-CP diets without AA supplementation grew more slowly, were less efficient in feed conversion, and developed carcasses that contained a smaller longissimus muscle, greater, average backfat depths, and a lower percentage of muscle compared with pigs fed the high-CP sequence of diets (P < .01). The reduction in growth performance, feed efficiency, longissimus muscle area, and percentage of muscle in pigs fed the low-CP diets was alleviated by LYS, TRP, and THR supplementation (P > .10). Although pigs fed the low-CP diets supplemented with AA had reduced average and 10th rib backfat depths compared with pigs fed the unsupplemented, low-CP diets (P < .01), these fat depth measures remained greater (P < .05) than those of pigs fed the high-CP diets. Feeding reduced dietary CP, regardless of AA supplementation, resulted in reduced heart (P < .10) and liver weights (P < .01) compared with feeding the high-CP diets.(ABSTRACT TRUNCATED AT 250 WORDS)

Optimum ratio to lysine of threonine, tryptophan, and sulfur amino acids for finishing swine.

Forty-eight crossbred (PIC line 26 x Camborough 15) pigs were used in two finishing trials to compare the ideal ratios of threonine (Thr), tryptophan (Trp), and sulfur amino acids (SAA) to lysine (Lys) determined for young pigs to a proposed ratio of these amino acids for finishing pigs. Trial 1 involved 20 barrows and 20 gilts that were self-fed in sex groups of two. Trial 2 was a Latin square design that used four barrows and four gilts that were individually fed in metabolism cages. Separate diets were used for the early (EF = 56 to 90 kg) and late (LF = 90 to 112 kg) finishing periods. Diets were formulated from a corn-soybean meal mixture and contained 11% CP and .55% digestible lysine for EF pigs and 10% CP and .50% digestible lysine for LF pigs. Negative-control diets in both the EF and LF periods were designed to be slightly deficient in lysine and to contain digestible Thr (65%), Trp (18%), and SAA (60%) at the ideal ratio to digestible Lys determined for 10- to 20-kg pigs. The experimental diet in both the EF and LF periods was formulated to contain digestible Thr (70%), Trp (20%), and SAA (65%) at the proposed ideal ratio to digestible Lys for finishing pigs. In Trial 1, increased ratios of Thr, Trp, and SAA improved gain:feed ratio, whole-body and carcass protein concentration, and whole-body and carcass protein accretion. In Trial 2, LF pigs responded to the increased ratios of Thr, Trp, and SAA with decreased urinary nitrogen excretion and increased N retention.(ABSTRACT TRUNCATED AT 250 WORDS)

Sorghum amino acid-supplemented diets for the 50- to 100-kilogram pig.

Three experiments were conducted to evaluate lysine (Lys), threonine (Thr), methionine (Met), tryptophan (Trp), and nonessential N (+N) supplementation of all sorghum grain (S) diets on growth and carcass characteristics of 50- to 100-kg pigs. In Exp. 1, four replicate pens of four pigs each were fed: 1) sorghum-soybean meal positive control (S-SBM); 2) S + Lys + Thr + Met + Trp to equal the amino acid concentrations in S-SBM (LTMT); 3) Diet 2 + N (LTMT+N); and 4) S negative control. Compared with pigs fed S-SBM, pigs fed LTMT or LTMT+N had reduced (P < .05) ADG, ADFI, serum urea N (SUN), pancreas weight, LMA, and percentage of muscling (PM) but higher dressing percentage (DP) and similar 10th rib fat thickness (TRF). Apparent N digestibility was lower (P < .05) in pigs fed LTMT than in pigs fed LTMT+N or S-SBM. In Exp. 2, two replicate pens of four pigs each were fed: 1) S-SBM; 2) S + Lys + Thr (LT); 3) S + Lys + Thr + Met (LTM); 4) S + Lys + Thr + Trp (LTT); 5) LTMT; 6 to 9) as 2 to 5 +N; and 10) S negative control. Compared with pigs fed S-SBM, pigs fed S, LT, LT+N, and LTM+N had lower (P < .05) ADG. Daily gain of pigs fed LTM, LTT, LTMT, LTT+N, or LTMT+N was not different (P > .10) from pigs fed S-SBM.(ABSTRACT TRUNCATED AT 250 WORDS)

Feed intake pattern of group-housed growing-finishing pigs monitored using a computerized feed intake recording system.

The feed intake pattern and growth performance of boars, barrows, and gilts fed diets differing in lysine and protein content were measured on 120 crossbred pigs from 27 (SD 3.7) to 81.5 (SD 9.2) kg live weight. The pigs were housed in eight mixed-sex groups with five pigs of each sex in each group. They were fed from an electronic feed station that recorded individual meal sizes and the time and duration of visits to the feeder for each animal in the group. Four dietary treatments were compared. During the grower period (27 to 55 kg), diets ranged in lysine content form .98 to 1.31%; for the remainder of the study, lysine content was .88 to 1.18%. Barrows had a greater (P < .01) number of meals per day than the other two sexes (7.4 vs 7.0 vs 7.0 +/- .10, respectively), but there were no significant differences among sexes for daily feed intake or other feed intake traits. Daily feed intake increased with dietary lysine content, largely because of increased meal sizes resulting from longer feeder occupation times at each visit. Visits to the feeder were greatest between 0900 and 1100 and lowest between 2000 and 0400. Correlations between feeding pattern and growth traits were relatively low. Repeatabilities of feeding pattern traits were generally higher when measured over shorter time periods. These results suggest a change in feeding behavior with increasing dietary lysine levels and a relatively small effect of sex on feeding pattern for mixed-sex groups of 15 pigs fed from a single electronic feed station.

Efficacy of a lysine-tryptophan blend for growth of chicks.

Two chick experiments were conducted to compare the growth-promoting efficacy as well as the toxicity of a new source of L-tryptophan and L-lysine, Tryptosine (16.1% tryptophan, 56.3% lysine). A corn-feather meal-soybean meal basal diet was made singly deficient in either lysine or tryptophan, and graded doses of lysine or tryptophan from either Tryptosine or feed-grade sources of lysine and tryptophan were supplemented. Linear (P < .01) weight gain responses occurred, and responses to lysine or tryptophan in Tryptosine were similar to those obtained with equal doses of lysine or tryptophan provided by feed-grade sources of L-lysine.HCI or L-tryptophan. The toxicity trial involved additions of 1, 2, or 4% lysine with .29, .58, or 1.16% tryptophan to a lysine- and tryptophan-adequate corn-soybean meal diet. Both amino acids were provided as either Tryptosine or as feed-grade sources of lysine and tryptophan. Weight gain and feed intake were reduced in a linear fashion (P < .01) as levels of the two excess amino acids increased. The decreases caused by Tryptosine were similar to those caused by equivalent levels of excess feed-grade lysine and tryptophan.

Evaluation of copper sulfate and a copper lysine complex as growth promoters for weanling swine.

Two 5-wk trials using 176 weanling pigs (average initial weight of 8.3 kg and age of 31 d) were conducted to examine the effect of feeding varying levels of dietary Cu from copper sulfate (CuSO4) or a copper lysine complex (CuLys) on performance, mineral stores, serum copper, and serum mitogenic activity. Dietary treatments were 0 (15 mg/kg of Cu in basal diet), 100, 150, or 200 mg/kg of supplemental Cu from CuSO4 or CuLys. Average daily gain and ADFI increased linearly (P < .01) with increasing dietary levels of Cu during wk 1 to 2, 3 to 5, and 1 to 5, with no difference (P > .10) between the Cu sources. Overall gain:feed ratios were not consistently affected by Cu source. Dietary Cu linearly increased liver, kidney (P < .001), and brain (P < .05) concentrations of Cu. In the liver, the linear response to supplemental Cu differed between Cu sources (P < .001); pigs fed 200 mg/kg of Cu from CuLys had the highest concentration of Cu. Serum Cu concentrations increased linearly during wk 1 to 2 (P < .01), 3 to 5, and 1 to 5 (P < .001), with no difference (P > .10) between sources. Serum mitogenic activity increased linearly during wk 1 to 2 and 1 to 5 (P < .05). Growth performance was linearly improved as the dietary level of Cu increased from 15 to 200 mg/kg, with similar responses for both Cu sources. Serum and tissue concentrations of Cu were generally equally affected by the two Cu sources, except liver Cu concentration, which was onefold higher for pigs fed 200 mg/kg of Cu as CuLys.

Interactive effects of dietary chromium tripicolinate and crude protein level in growing-finishing pigs provided inadequate and adequate pen space.

An experiment was conduct to determine the interactive effects of dietary chromium tripicolinate (CrPic), CP, and pen space (PS) as a stress on growth performance, carcass traits, and plasma hormones and metabolites of crossbred growing-finishing pigs (128 pigs; initial BW 27.2 kg). A factorial arrangement of treatments included two levels of Cr (0 and 400 ppb as CrPic), two levels of CP (80 [80P] and 120% [120P] of the lysine requirement; NRC, 1988), and two levels of PS (adequate [APS] or inadequate [IPS]). In the grower phase, ADG was decreased more by IPS when pigs were fed 80P (CP x PS, P < .08). Gain/feed (G/F) was decreased by IPS in pigs fed 80P; however, in pigs fed 120P, IPS increased G/F (CP x PS, P < .01). Supplemental Cr did not affect (P > .10) ADG, ADFI, or G/F in the grower phase. In the finisher phase, pigs, fed 120P had less (P < .10) ADFI but similar (P > .10) ADG compared with pigs fed 80P. Gain/feed was higher (P < .10) in pigs fed 120P than in pigs fed 80P. Daily gain ADFI were lower (P < .03) in pigs provided IPS than in pigs provided APS. In pigs fed 80P, CrPic tended to result in higher ADG and G/F; however, in pigs fed 120P, Cr tended to result in lower ADG and G/F (CP x Cr, P < .09). Pigs fed 120P had greater (P < .03) longissimus muscle area (LMA) and percentage of muscling (PM) and less (P < .03) 10th rib fat thickness (TRF) than pigs fed 80P. Pigs provided IPS had greater LMA and PM and less TRF than pigs provided APS (P < .03). Pigs fed CrPic had higher TRF when provided IPS but lower TRF when provided APS (Cr x PS, P < .07). Feeding CrPic had minimal effect on plasma urea N, cholesterol, glucose, NEFA, insulin, or growth hormone.

Protein requirements of growing steers limit-fed corn-based diets.

In Exp. 1, six steers (254 kg) were used in a 6 x 4 incomplete Latin square to determine the effects of solvent-extracted soybean meal alone or in combination with rumen-protected methionine and lysine on N balance in steers limit-fed a high-corn diet to gain 1.1 kg/d. The basal diet contained (DM basis) 80% rolled corn, 15% alfalfa, and .9% urea (13.9% CP), and 2 or 4% soybean meal replaced corn to give CP concentrations of 14.8 and 15.6%, respectively. Each diet was fed with and without 5 g/d of Smartamine-ML (.75 and 2.0 g of rumen-protected methionine and lysine, respectively). Nitrogen retention increased linearly (P = .09) with level of soybean meal. Rumen-protected methionine and lysine had no effect on N balance. In Exp. 2, seven steers (233 kg) were used in a 7 x 4 incomplete Latin square experiment to investigate optimal levels and sources of CP for steers limit-fed to gain 1 kg/d. Treatments included a negative-control diet (urea; 11.7% CP) and six diets containing either 13.5, 15.4, or 17.2% CP with either solvent-extracted or expeller-processed soybean meal. Diets provided 75, 87.5, 100, or 112.5% of estimated CP requirement for a gain of 1 kg/d. The basal diet contained 83% rolled corn, 15% alfalfa, and .2% urea. Nitrogen retention increased linearly (P = .006) with soybean meal addition, and no differences were observed between CP sources. The CP system underpredicted the protein requirements of limit-fed steers under our conditions.

The lysine requirement and ratio of total sulfur amino acids to lysine for chicks fed adequate or inadequate lysine.

Experiments (Exp.) were conducted with Cornish Rock males (4 to 14 or 15 d of age) to determine the Lys requirement (Exp. 1) and the optimum ratio of TSAA:Lys for chicks fed adequate or inadequate Lys (Exp. 2). In Exp. 1, 180 chicks were allotted on the basis of BW to six treatments with six replications of five chicks each in a completely randomized design (CRD). Average initial and final BW were 73.5 and 415.5 g. The Lys levels fed were: 0.8, 0.9, 1.0, 1.1, 1.2, and 1.3% digestible Lys. In Exp. 2, 240 chicks were allotted on the basis of BW to 12 treatments with four replications of five chicks each in a CRD. Average initial and final BW were 68.5 and 336.3 g. Chicks were fed either 0.82 or 1.0% digestible Lys and within each Lys level, a ratio of TSAA:Lys of: 0.55, 0.63, 0.72, 0.80, 0.88, and 0.96, resulting in a 2 x 6 factorial arrangement of treatments. At the end of each trial, all chicks were weighed and pen feed consumption was measured. In Exp. 1, average daily gain (ADG) and gain:feed (GF) increased (linear, P < 0.01; quadratic, P < 0.02) as dietary Lys increased. A cubic (P < 0.04) effect of Lys for average daily feed intake (ADFI) was observed. One-slope, broken-line regression models estimated Lys requirements of 1.0, 0.9, and 1.1% for ADG, ADFI, and GF, respectively. In Exp. 2, chicks fed 1.0% Lys had higher (P < 0.01) ADG, ADFI, and GF than chicks fed 0.82% Lys. Daily gain, ADFI, and GF increased (linear, P < 0.01; quadratic, P < 0.01) as TSAA:Lys increased. For ADG, ADFI, and GF, one-slope, broken-line regression models estimated required ratios of TSAA:Lys of 0.66, 0.71, and 0.63 for chicks fed 1.0% Lys and 0.66, 0.67, and 0.63 for chicks fed 0.82% Lys. There were no differences (P > 0.05) in the estimated ratios of TSAA:Lys required to maximize ADG, ADFI, and GF for chicks fed 0.82 and 1.0% Lys. Thus, similar ratios of an indispensable amino acid to Lys can be obtained when chicks are fed at or slightly below their Lys requirement.

Efficacy of phase-feeding in supporting growth performance of broiler chicks during the starter and finisher phases.

A feeding regimen has been developed that uses regression equations to predict amino acid requirements over time. Phase-feeding (PF) of broilers was tested to evaluate its efficacy compared with feeding broilers NRC or Illinois ideal chick protein (IICP) recommendations. In Experiment 1, NRC or IICP requirements for lysine, sulfur amino acids, and threonine were fed from 0 to 21 d, whereas PF was tested using a series of three diets (0 to 7, 7 to 14, and 14 to 21 d). No differences (P > 0.05) in weight gain, feed intake, feed efficiency, digestible amino acid intake, or gain per unit digestible amino acid intake were noted among chicks fed NRC, IICP, or PF diets. In Experiment 2, NRC or IICP requirements were fed from 40 to 61 d, whereas PF was tested using a series of three diets (40 to 47, 47 to 54, and 54 to 61 d). No differences (P > 0.05) in weight gain or feed intake were observed, but the feed efficiency of birds fed the IICP diet was decreased (P < 0.05). The IICP and PF diets resulted in decreased (P < 0.05) digestible lysine and threonine intake; gain per unit digestible lysine and threonine intake was increased (P < 0.05) by PF. No differences (P < 0.05) in breast meat, wing, or leg yield were noted among treatments. Economic analysis indicated that PF may facilitate reduced dietary costs without sacrificing growth performance or carcass yield.