Middle interhemispheric variant of holoprosencephaly: a distinct cliniconeuroradiologic subtype

BACKGROUND

The middle interhemispheric variant (MIH) is a subtype of holoprosencephaly (HPE) in which the posterior frontal and parietal areas lack midline separation, whereas more polar areas of the cerebrum are fully cleaved. While the neuroradiologic features of this subtype have been recently detailed, the clinical features are largely unknown.

OBJECTIVE

To present the clinical manifestations of MIH and to compare them with classic subtypes (alobar, semilobar, and lobar) of HPE.

METHODS

The authors evaluated 15 patients with MIH in a multicenter study. Neuroimaging and clinical data were collected and correlated. They compared the data with those of 68 patients who had classic HPE.

RESULTS

The frequency of endocrinopathy in MIH (0%) was lower compared with the classic subtypes (72%) (p < 0.0001). This correlated with the lack of hypothalamic abnormalities. The percentage of patients with seizures (40%) did not significantly differ from classic HPE. Spasticity was the most common motor abnormality, seen in 86% of MIH patients, similar to other subtypes. The frequency of choreoathetosis in MIH (0%) was lower than that for semilobar HPE (41%) (p < 0.0039). This correlated with the lack of caudate and lentiform nuclei abnormalities. Developmental functions, including mobility, upper-extremity function, and language, of the MIH group were similar to the least severe classic type, lobar HPE.

CONCLUSION

MIH is a recognizable variant of HPE with differing clinical prognosis. Similar to the lobar subtype by functional measures, MIH differs from classic HPE by the absence of endocrine dysfunction and choreoathetosis.

Nitrogen metabolism and growth performance of gilts fed standard corn-soybean meal diets or low-crude protein, amino acid-supplemented diets

Two experiments were conducted to determine the CP concentration below which N retention and growth performance are reduced when low-protein, amino acid-supplemented, corn-soybean meal diets are fed. In a N balance trial (Exp. 1), 12 gilts (initial weight 41 kg) were fitted with urinary catheters and fed six different diets during three 7-d periods in an incomplete block design. The diets were: 1) 18% CP; 2) 14% CP + AA, 3) 16% CP; 4) 12% CP + AA; 5) 14% CP; and 6) 10% CP + AA. Amino acids (lysine, threonine, tryptophan, and methionine) were supplemented such that the concentrations in the low-protein diets were equal to those in their standard (4% CP higher) counterparts. Nitrogen retention (g/d) decreased (P < 0.01) as CP decreased, in both standard (27.10, 24.53, and 20.99) and low-protein (21.51, 19.18, and 15.83) diets, but was lower (P < 0.01) in low-protein diets. There were no differences among treatments (P > 0.05) in biological value (68.2% standard vs 71.0% low-protein). In a growth performance trial (Exp. 2), 36 gilts (initial weight 19.5 kg) were penned individually and fed one of six diets for 35 d in a randomized complete block design. Dietary treatments were a 16% CP standard diet and low-protein diets formulated to contain 15, 14, 13, 12, and 11% CP supplemented with crystalline lysine, tryptophan, threonine, and methionine to equal the total concentrations in the standard diet. Protein concentration affected (P < or = 0.05) ADG, ADFI, feed efficiency, fat-free lean gain, longissimus muscle area, plasma urea, and plasma concentrations of most essential AA. For most of these traits, the major difference was poor performance of pigs fed the 11% CP diet. Thus, in Exp. 1, at AA concentrations from deficient to excess, low-protein, amino acid-supplemented diets failed to produce the same N retention as the equivalent corn-soybean meal diets. However in Exp. 2, the same performance was obtained with 16, 15, 14, 13, and 12% CP. Based on these data, we suggest that N balance is more sensitive than growth to amino acid adequacy andthat other AA (e.g., isoleucine and valine) may limit growth performance when the protein concentration is reduced by more than four percentage units.

Degree of amino acid restrictions during the grower phase and compensatory growth in pigs selected for lean growth efficiency

A total of 32 select line (SL) and 32 control line (CL) Duroc pigs were used in two trials to determine the effect of dietary amino acid contents during the grower (G) phase and selection for lean growth efficiency on growth performance, carcass traits, and meat quality. In each trial, pigs weighing 20 kg were assigned to 16 pens with two gilts or two castrated males per pen, and pens were randomly assigned within the genetic line to corn-soybean meal G diets formulated to contain 5.0, 7.0, 9.0, or 11.0 g lysine/kg. After 50 kg, all pigs were fed common finisher 1 (F1) and finisher 2 (F2) diets. Pigs were allowed ad libitum access to feed and water. After the initial statistical analyses, the data sets from the two trials were combined. During the G phase, pigs consumed less feed [linear (Ln), P < 0.001] and more lysine (Ln, P < 0.001), grew faster (Ln, P < 0.05) but utilized feed more and lysine less efficiently (Ln, P < 0.001) for weight gain as the amino acid content of G diets increased. Increasing dietary amino acids resulted in less ultrasound backfat (Ln, P < 0.001) and more serum urea nitrogen [Ln, P < 0.001; quadratic (Qd), P < 0.01] at the end of the G phase. Pigs grew more slowly during the F1 (Ln, P < 0.01 and Qd, P = 0.05) and F2 (Ln, P = 0.07) phases and utilized feed and lysine less efficiently (Ln, P < 0.05) for weight gain during the F1 phase as the amino acid content of G diets increased. The grower diet had no effect on overall weight gain and feed efficiency, carcass traits, or meat quality scores. The efficiency of lysine utilization for overall weight gain (Ln, P < 0.001) and lean accretion (Ln, P < 0.05) improved as the amino acid content of G diets decreased. The SL pigs grew faster (P < 0.05) and had less (P < 0.001) ultrasound backfat throughout the study compared with the CL pigs. The SL pigs had less 10th rib backfat (P < 0.001) and tended to have larger longissimus muscle area (P = 0.09) than the CL pigs, which were reflected in greater rate (P < 0.001) and efficiency (P < 0.05) of lean accretion. Marbling (P < 0.05) and meat color (P = 0.07) scores were lower in the SL pigs. No grower diet x genotype interactions were observed in response criteria of interest. The results indicate that pigs subjected to dietary amino acid restrictions during the G phase (as low as 5.0 g lysine/kg) compensated completely in terms of growth rate and body composition regardless of the genotype. Compensatory growth can have a positive impact not only on the overall efficiency of pig production but also on the environment by reducing excretion of unused nutrients.

Body composition and tissue accretion rates of barrows fed corn-soybean meal diets or low-protein, amino acid-supplemented diets at different feeding levels

Two experiments, each with 39 high-lean-gain potential barrows, were conducted to evaluate the organ weights, body chemical composition, and tissue accretion rates of pigs fed corn-soybean meal diets (CONTROL) and low-protein diets supplemented with crystalline lysine, threonine, tryptophan, and methionine either on an ideal protein basis (IDEAL) or in a pattern similar to that of the control diet (AACON). Amino acids were added on a true ileally digestible basis. The initial and final BW were, respectively, 31.5 and 82.3 kg in Exp. 1 and 32.7 and 57.1 kg in Exp. 2, and pigs were fed for 55 and 27 d in Exp. 1 and 2, respectively. In Exp. 1, the CONTROL and IDEAL diets were offered on an ad libitum basis, or by feeding 90 or 80% of ad libitum intake. In Exp. 2, the CONTROL, IDEAL, and AACON diets were offered on an ad libitum basis, or by feeding 80% of the ad libitum intake. Three pigs were killed at the start of the experiments and three from each treatment were killed at the end of each experiment to determine body chemical composition. In both trials, the whole-body protein concentration (g/kg) and the accretion rates of protein (g/d) were greater (P < 0.05) for pigs fed the CONTROL than for pigs fed the IDEAL and AACON diets. In Exp. 1, pigs fed the CONTROL diet had a trend (P < 0.10) for greater water and lower lipid concentration and had greater (P < 0.05) water and ash accretion rates. Whole-body protein concentration was greatest (P < 0.05) in pigs fed at 80% of ad libitum, but protein, water, and ash accretion rates were greatest (P < 0.05) in pigs allowed ad libitum access to feed. In summary, pigs fed the IDEAL and the AACON diets had less protein in the body and lower protein accretion rates than pigs fed the CONTROL diet. It seems that reductions in protein deposition in pigs fed the IDEAL and AACON diets may have been due to a deficiency of one or more essential amino acids or possibly to increases in the NE for metabolic processes leading to increases in adipose tissue deposition.

Growth performance, diet apparent digestibility, and plasma metabolite concentrations of barrows fed corn-soybean meal diets or low-protein, amino acid-supplemented diets at different feeding level

Two experiments, each with 36 barrows with high-lean-gain potential, were conducted to evaluate apparent nutrient digestibilities and performance and plasma metabolites of pigs fed corn-soybean meal diets (CONTROL) and low-protein diets. The low-protein diets were supplemented with crystalline lysine, threonine, tryptophan, and methionine either on an ideal protein basis (IDEAL) or in a pattern similar to that of the control diet (AACON). Amino acids were added on a true ileally digestible basis. The initial and final BW were, respectively, 31.5 and 82.3 kg in Exp. 1 and 32.7 and 57.1 kg in Exp. 2. In Exp. 1, the CONTROL and IDEAL diets were offered on an ad libitum basis or by feeding 90 or 80% of ad libitum intake. Pigs were fed for 55 d. In Exp. 2, the CONTROL, IDEAL, and AACON diets were offered on an ad libitum basis or by feeding 80% of the ad libitum intake. Pigs were fed for 27 d. Pigs fed the CONTROL diet had greater (P < 0.05) ADG and feed efficiency (G/F) than pigs fed the IDEAL (Exp. 1 and 2) and AACON diets (Exp. 2). As the level of feed intake decreased, ADG decreased (P < 0.05), but G/F tended to improve (P < 0.10) for pigs fed 90% of ad libitum in Exp. 1 and for pigs fed 80% of ad libitum in Exp. 2. In Exp. 1, the apparent total tract digestibilities of DM and energy were greater (P < 0.01) for pigs fed the IDEAL diet than for pigs fed the CONTROL diet. In Exp. 2, the apparent total tract digestibility of protein was greatest in pigs fed the CONTROL diet (P < 0.05) and was greater (P < 0.05) in pigs fed the AACON diet than in pigs fed the IDEAL diet. Plasma urea concentrations were lower in pigs fed the IDEAL diet than in pigs fed the CONTROL diet, regardless of feeding level. For pigs fed the CONTROL diet, plasma urea concentrations were lower when feed intake was 80% of ad libitum (diet level, P < 0.01). In summary, pigs fed the IDEAL and the AACON diets gained less and had lower plasma urea concentrations than pigs fed the CONTROL diet. Based on these data, it seems that the growth potential of pigs fed the IDEAL and AACON diets may have been limited by a deficiency of lysine, threonine, and(or) tryptophan and that the amino acid pattern(s) used was not ideal for these pigs.

Dietary manipulation to reduce aerial ammonia concentrations in nursery pig facilities

Two 4-wk trials (preliminary study) and three 5-wk trials (major study) were conducted to determine the effects of adding Yucca schidigera extract or anhydrous calcium chloride to nursery diets on the growth performance of nursery pigs and aerial ammonia concentration. The pigs were weaned between 13 and 15 d of age and had an initial BW of 3 to 6 kg. In each trial, pigs were allotted to three identical pig nursery rooms that were environmentally regulated. There were three diets (one diet per room): 1) control, containing 23% CP; 2) control plus 125 ppm of Yucca schidigera extract; and 3) control plus 1.95% anhydrous calcium chloride. Growth performance was recorded weekly. Aerial ammonia concentration was measured daily using aspiration detector tubes and during the last week of each trial using diffusion tubes. Manure samples were collected twice a week during the experimental period to determine ammonia and N concentrations and pH. Plasma urea concentration was determined in blood samples collected from the pigs at the end of each trial. Data were analyzed using split-plot and Latin square designs for the preliminary and major studies, respectively. Feed intake was similar among pigs fed all three diets. There were no differences in ADG and ADG/ADFI (G/F) between pigs fed the control diet and pigs fed the yucca extract diet (P > or = 0.41). In all trials, pigs fed the calcium chloride diet had lower ADG and G/F than pigs fed the other two diets (P < 0.05). In the preliminary study, aerial ammonia tended to be greater in the rooms in which pigs were fed the control diet than in the rooms with pigs fed the yucca extract diet (P = 0.08) and the calcium chloride diet (P = 0.11). In the major study, aerial ammonia increased weekly (diet x week; P < 0.001) in all rooms. In the 4th wk, ammonia concentrations were greater (P < 0.001) in the rooms in which pigs were fed the control diet than in the rooms in which the other two diets were fed. Dietary treatment had no effect on plasma urea concentration (P > or = 0.10), manure ammonia and N concentrations (P > or = 0.50), and manure pH (P > or = 0.78). Although aerial ammonia concentrations were relatively low, the addition of Yucca schidigera extract or calcium chloride to the diet of nursery pigs reduced ammonia concentrations in the nursery rooms.

Effect of pharmacological concentrations of zinc oxide with or without the inclusion of an antibacterial agent on nursery pig performance

A study involving nine research stations from the NCR-42 Swine Nutrition Committee used a total of 1,978 crossbred pigs to evaluate the effects of dietary ZnO concentrations with or without an antibacterial agent on postweaning pig performance. In Exp. 1, seven stations (IA, MI, MN, MO, NE, ND, and OH) evaluated the efficacy of ZnO when fed to nursery pigs at 0, 500, 1,000, 2,000, or 3,000 mg Zn/kg for a 28-d postweaning period. A randomized complete block experiment was conducted in 24 replicates using a total of 1,060 pigs. Pigs were bled at the 28-d period and plasma was analyzed for Zn and Cu. Because two stations weaned pigs at < 15 d (six replicates) and five stations at > 20 d (18 replicates) of age, the two sets of data were analyzed separately. The early-weaned pig group had greater (P < 0.05) gains, feed intakes, and gain:feed ratios for the 28-d postweaning period as dietary ZnO concentration increased. Later-weaned pigs also had increased (P < 0.01) gains and feed intakes as the dietary ZnO concentration increased. Responses for both weanling pig groups seemed to reach a plateau at 2,000 mg Zn/kg. Plasma Zn concentrations quadratically increased (P < 0.01) and plasma Cu concentrations quadratically decreased (P < 0.01) when ZnO concentrations were > 1,000 mg Zn/kg. Experiment 2 was conducted at seven stations (KY, MI, MO, NE, ND, OH, and OK) and evaluated the efficacy of an antibacterial agent (carbadox) in combination with added ZnO. The experiment was a 2 x 3 factorial arrangement in a randomized complete block design conducted in a total of 20 replicates. Carbadox was added at 0 or 55 mg/kg diet, and ZnO was added at 0, 1,500, or 3,000 mg Zn/ kg. A total of 918 pigs were weaned at an average 19.7 d of age. For the 28-d postweaning period, gains (P < 0.01), feed intakes (P < 0.05), and gain:feed ratios (P < 0.05) increased when dietary ZnO concentrations increased and when carbadox was added. These responses occurred in an additive manner. The results of these studies suggest that supplemental ZnO at 1,500 to 2,000 mg Zn/kg Zn improved postweaning pig performance, and its combination with an antibacterial agent resulted in additional performance improvements.

Variability among sources and laboratories in analyses of wheat middlings. NCR-42 Committee on Swine Nutrition

A cooperative research study was conducted by members of a regional committee (North Central Regional Committee on Swine Nutrition [NCR-42]) to assess the variability in nutrient composition (DM, CP, Ca, P, Se, NDF, and amino acids) of 14 sources of wheat middlings from 13 states (mostly in the Midwest). A second objective was to assess the analytical variability in nutrient assays among 20 laboratories (labs; 14 experiment station labs and six commercial labs). Wheat middlings were obtained from each participating station's feed mill. The bulk density of the middlings ranged from 289 to 365 g/L. The number of labs that analyzed samples were as follows: DM and CP, 20; Ca, 16; P, 15; Se, 7; NDF, 10; and amino acids, 9. Each lab used its own analytical procedures. The middlings averaged 89.6% DM, 16.2% CP, .12% Ca, .97% P, 36.9% NDF, .53 mg/kg Se, .66% lysine, .19% tryptophan, .54% threonine, .25% methionine, .34% cystine, .50% isoleucine, and .73% valine. As expected, there was considerable variation in nutrient composition among the 14 sources (P < .01), especially for Ca (.08 to .30%) and Se (.05 to 1.07 mg/kg). "Heavy" middlings (high bulk density, >335 g/L), having a greater proportion of flour attached to the bran, were lower in CP, lysine, P, and NDF than "light" middlings (<310 g/L), having cleaner bran, resulting in negative correlations between bulk density and CP (r = -.61), lysine (r = -.59), P (r = -.54), and NDF (r = -.81). Each 1-percentage-point increase in CP in the wheat middlings was associated with .0235 (r2 = .61) and 2.1 (r2 = .39)-percentage-point increases in lysine and NDF, respectively. Lysine content was associated with NDF, CP, and bulk density of wheat middlings (r2 = .88). There was considerable variation among laboratories (P < .01) in analysis of all nutrients. The CV among sources (100 x sigmaS/mean) was greater than among labs (100 x sigmaL/mean) for CP, Ca, P, Se, and NDF, but the CV among labs was greater than that among sources for DM and all of the amino acids except lysine and phenylalanine.

Further assessment of the dietary lysine requirement of finishing gilts

A cooperative research study involving 635 gilts was conducted at eight research stations to further estimate the lysine requirement of finishing gilts. Dietary crude protein levels of the five dietary treatments ranged from 16.0 to 24.4% with calculated lysine levels of .80, .95, 1.10, 1.25, or 1.40%. Each station contributed a minimum of two replicate pens of pigs per treatment. Average initial and final weights were 53.6 and 116.4 kg, respectively. At the end of the experimental period, pigs were killed and hot carcass weight, 10th-rib fat depth, and longissimus muscle area were measured. Carcass fat-free lean percentage and fat-free lean gain were estimated from these data. Daily lysine intakes averaged 21.8, 25.9, 30.5, 34.3, and 37.8 g/d for the five treatment groups, respectively. Increasing the dietary lysine from .80 to .95% numerically increased weight gain and gain:feed, but these increases were not maintained at higher levels of dietary lysine. Overall, rate and efficiency of gain decreased (cubic, P < .01) with increasing dietary lysine. Carcasses were leaner at the two higher levels of dietary lysine as evidenced by reduced 10th rib backfat (linear, P < .01), increased longissimus area (quadratic, P < .04), and increased percentage of estimated fat-free lean (linear, P < .01). Carcass fat-free lean gain was not influenced by dietary lysine except for a small numerical improvement (P < .11) at the .95% level of dietary lysine that paralleled the improvement in body weight gain. The results indicate that the dietary lysine requirement of finishing gilts with a mean carcass fat-free lean growth rate of 306 g/d from 54 to 116 kg body weight is probably no higher than .80% of the diet to achieve maximum rate and efficiency of body weight gain and carcass lean growth rate. The results also indicate that higher dietary lysine levels may increase carcass leanness in finishing gilts, possibly due to reduced intake of NE. Whether this response is due to the effects of lysine alone, protein (i.e., other amino acids), or soybean meal is unknown.

Effect of dietary concentration of metabolizable lysine on finishing cattle performance

A finishing trial and a metabolism trial were conducted to determine the effect of supplemental metabolizable Lys level on finishing calf performance and to estimate the metabolizable Lys requirement of finishing calves. The finishing trial included 60 individually fed crossbred beef steer calves (237 kg; SD = 20 kg) supplemented with either incremental amounts of rumen-protected Lys and Met, or Met alone. Addition of Lys and Met improved gains and efficiencies (quadratic; P < .02) during the first 56 d. There was no response to supplemental Met alone, suggesting that supplemental Lys rather than Met was responsible for the improvement in performance. Using nonlinear analyses to compare gain relative to supplemental Lys intake, maximum gain was determined to be 2.10 kg/d, or .27 kg/d above the zero Lys control, at a supplemental Lys intake of 2.56 g/d. Steers supplemented with 3 and 4 g of Lys had a weight advantage over the control steers of 16 kg at 56 d and 32 kg at the end of the 161-d trial. However, there were no statistical responses to Lys or Met during any periods after 56 d. During a separate metabolism trial, four steers fed the control finishing diet were slaughtered, and abomasal contents were collected for amino acid analyses. The predicted (Level 1 NRC, 1996) metabolizable protein flow to the abomasum for the control diet was 715 g/d, and the predicted Lys flow was 37.9 g/d. A supplemental Lys intake of 2.56 g/d would increase the Lys flow to 40.5 g/d. Feedlot diets low in ruminal escape protein may be deficient in metabolizable Lys, especially early in the feeding period. The metabolizable Lys requirement of steer calves gaining 2.10 kg/d is estimated to be 40.5 g/d.

Exogenous growth hormone induces somatotrophic gene expression in neonatal liver and skeletal muscle

The extent to which the local somatotrophic axis is functional in extrahepatic tissues in the neonate is unclear. We therefore determined the expression of growth hormone (GH) receptor (GHR), and insulin-like growth factors I and II (IGF-I and IGF-II) mRNA in liver and skeletal muscle (longissimus) of neonatal pigs given daily intramuscular injections of either recombinant porcine GH (1 mg/kg body wt; n = 6) or saline (n = 5) for 7 days. Exogenous GH increased plasma concentrations of GH 30-fold and IGF-I threefold. Abundances of specific mRNA in liver and muscle were measured by RNase protection assays (values are arbitrary density units). In liver, GH treatment increased GHR (6.0 vs. 9.7; P < 0.01) and IGF-I (5.2 vs. 49.0; P < 0.001) but not IGF-II (19.5 vs. 17.2) mRNA. In muscle, GH treatment increased IGF-I mRNA (13.3 vs. 22.8; P < 0.05) but not GHR (8.3 vs. 9.5) or IGF-II (16.1 vs. 16.9). These results demonstrate that exogenous GH can induce local somatotrophic function predominantly in liver but also in muscle of newborn pigs. Our novel finding on the selective increase in muscle IGF-I but not GHR gene expression suggests differences in posttranscriptional regulation and/or intracellular signaling mechanisms.

Growth promotion effects and plasma changes from feeding high dietary concentrations of zinc and copper to weanling pigs (regional study)

An experiment was conducted to determine the effect of high dietary intakes of Zn and Cu and their combination on growth performance of weanling pigs with diverse health status and management strategies. Twelve experiment stations cooperated and used a total of 1,356 pigs that averaged 6.55 kg BW and 22.2 d age at weaning. The four dietary treatments, all of which met or exceeded NRC requirements, were 1) control, 2) 3,000 ppm Zn (from Zn oxide), 3) 250 Cu ppm (from Cu sulfate), or 4) 3,000 ppm Zn and 250 ppm Cu. The diets were fed as a complex Phase I diet (1.4% lysine) for 7 d followed by a Phase II diet (1.2% lysine) for 21 d. Chlortetracycline (220 ppm) was added to all diets. Fecal color (1 = yellow to 5 = black) and consistency (1 = very firm to 5 = very watery) were scored daily for 3 wk. At the end of the 28-d study, 412 pigs were bled at five stations, and plasma Cu, Zn, and Fe concentrations were determined at one station with atomic absorption spectrophotometry. Average daily gain (375, 422, 409, 415 g/d), feed intake (637, 690, 671, 681 g/d), and gain/feed (586, 611, 611, 612 g/kg) were improved (P < .01) by the addition of Zn and(or) Cu. Significant Cu x Zn interactions imply that the responses to Zn and Cu were independent and not additive. There were significant (P < .01) Zn and Cu effects and a Zn x Cu interaction on fecal color (3.17, 3.24, 4.32, 3.57) and consistency (2.39, 2.14, 2.14, 2.13). Dietary additions of Cu and Zn resulted in elevated plasma concentrations of Cu and Zn, respectively. These data indicate that pharmacological additions of 3,000 ppm Zn (oxide) or 250 ppm Cu (sulfate) stimulate growth beyond that derived from intakes of Zn and Cu that meet nutrient requirements. However, the combination of Zn and Cu did not result in an additive growth response.

Sulphonation of N-hydroxy-2-acetylaminofluorene by human dehydroepiandrosterone sulphotransferase

1. The aim was to determine which human recombinant sulphotransferase (ST) isoform(s) were responsible for the sulphonation and, thus, potential further bioactivation of the classical hepatic procarcinogen N-hydroxy-2-acetylaminofluorene (N-OH-2AAF). 2. N-OH-2AAF was incubated together with the cosubstrate 3'-phosphoadenosine-5'-phosphosulphate (PAPS) and either human liver cytosol or recombinant P-form phenolsulphotransferase (P-PST), M-form PST, dehydroepiandrosterone-ST (DHEA-ST) or oestrogen ST (EST). Formation of 3'-phosphoadenosine-5'-phosphate (PAP) from PAPS, measured by HPLC, was used as the assay for determination of sulphoconjugation rates. 3. The liver cytosol produced a 100% increase in PAP formation in the presence of 200 microM N-OH-2AAF as compared with baseline levels (p < 0.01), corresponding to a rate of 19 pmol/min/mg protein. Recombinant P-PST, however, was without effect. This is in contrast to previous suggestions using crude enzyme preparations. Like P-PST, recombinant M-PST and EST did not sulphonate N-OH-2AAF. On the other hand, recombinant DHEA-ST produced a 161% increase in PAP formation in the presence of 200 microM N-OH-2AAF as compared with baseline values (p < 0.001). 4. Kinetic studies of N-OH-2AAF sulphonation by DHEA-ST and human liver cytosol gave similar apparent Kms. Interestingly, the Vmax for N-OH-2AAF sulphonation by DHEA-ST was very similar to that of DHEA, the natural substrate for DHEA-ST. 5. This is the first paper to demonstrate the involvement of the human DHEA-ST in the sulphonation of an N-hydroxylated aromatic amide carcinogen.

Growth performance and digestive and metabolic responses of gilts penned individually or in groups of four

Two experiments were conducted to identify factors involved in the growth retardation of pigs housed in groups. In each experiment, 60 gilts were allotted to two treatments in a randomized complete block design. Twelve gilts were penned individually with one feeder, one waterer, and a space allowance of 1.5 m2 per pen. Forty-eight gilts were allocated to 12 groups of four and penned together with four feeders, four waterers, and a space allowance of 6 m2 per pen. In Exp. 1 there were 60 growing gilts (initial and final BW of 17.9 and 50.8 kg, respectively), and in Exp. 2 there were 60 finishing gilts (initial and final BW of 46.0 and 118.3 kg, respectively). In Exp. 1 there was a trend (P < .10) toward greater final BW, ADG, and average backfat thickness of gilts penned individually. Apparent digestibilities of DM, CP, and energy tended (P < .10) to be greater and plasma NEFA concentrations were lower (P < .05) for gilts penned individually. Plasma concentrations of urea and glucose were similar between treatments. In Exp. 2, ADG was greater (P < .05) and there was a trend (P < .10) for greater final weight, ADFI, loin weight, and primal cut weight of gilts penned individually. Apparent digestibilities of DM, CP, and energy and the plasma concentrations of urea, glucose, and NEFA were similar in both treatments. In summary, growing gilts penned four per group had reductions in daily gain, backfat thickness, and apparent digestibilities of DM, CP, and energy and increases in plasma NEFA concentrations. Finishing gilts penned four per group had reductions in daily gain and feed intake with no changes in apparent nutrient digestibilities or plasma metabolite concentrations compared to individually penned gilts.

Metabolize methionine and lysine requirements of growing cattle

Two growth studies were conducted to determine the Met and Lys requirements of growing cattle. In each 84-d trial, steer calves were fed individually diets containing 44% sorghum silage, 44% corn cobs, and 12% supplement (DM basis) at an equal percentage of BW. In Trial 1, 95 crossbred steers (251 kg) were supplemented with urea or meat and bone meal (MBM). Incremental amounts of rumen-protected Met were added to MBM to provide 0, .45, .9, 1.35, 3, and 6 g/d metabolizable Met. In Trial 2, 60 steers (210 kg) were supplemented with urea or corn gluten meal (CGM). Incremental amounts of rumen-protected Lys were added to CGM to provide 0, 1, 2, 3, 4, 5, 6, 8, and 10 g/d metabolizable Lys. Supplementation with MBM and CGM increased the supply of metabolizable protein to the animal. Steers fed MBM plus 0 Met gained 49 g/d more than steers fed urea, whereas steers fed CGM plus 0 Lys gained 150 g/d more than steers fed urea. Supplementation of rumen-protected Met and Lys improved ADG in steers fed MBM and CGM, respectively (P < .10). Nonlinear analysis, comparing gain vs supplemental Met and Lys intake, predicted supplemental Met and Lys requirements of 2.9 and .9 g/d, respectively. This amount of additional Met promoted .13 kg/ d gain greater than MBM alone, and this amount of additional Lys promoted .10 kg/d gain greater than the CGM alone. Metabolizable Met and Lys requirements were predicted from Level 1 of NRC (1996) calculated metabolizable protein supply, amino acid analysis of abomasal contents, and the maximum response to supplemental AA. Steers gaining .39 kg/d required 11.6 g/ d Met or 3. 1% of the metabolizable protein requirement, whereas steers gaining .56 kg/d required 22.5 g/d Lys or 5.7% of the metabolizable protein requirement.

Evaluation of feather meal as a source of sulfur amino acids for growing steers

In situ and digestion studies were conducted to evaluate feather meal (FTH), blood meal (BM), and meat and bone meal (MBM) for escape protein content, amino acid composition of the escape protein, true protein digestibility, and digestibility of the individual amino acids. Following 12 h of ruminal incubation, escape protein values were 73.5, 92.4, and 60.8% of CP for FTH, BM, and MBM, respectively. Blood meal and MBM were poor sources of sulfur amino acids (SAA), whereas FTH was a good source. Most of the SAA of FTH, however, was Cys, with very little Met. True protein digestibilities were not different for the protein sources (P > .15), ranging from 86.7 to 94.0% of the CP. However, digestibilities of the individual amino acids were quite different. Two growth studies were conducted to evaluate FTH as a source of SAA for growing cattle. The first study used 120 steers (228 +/- 15 kg) supplemented with urea, MBM, MBM plus 1% FTH, or MBM plus 2% FTH. Additionally, incremental amounts of rumen-protected Met were added to treatments containing MBM. Supplementation of MBM increased (P < .05) ADG compared with the urea control. Addition of FTH to MBM resulted in a linear (P < .01) increase in ADG. However, addition of rumen-protected Met to MBM plus FTH treatments further improved gains. Although FTH is an effective source of SAA, Met probably was first-limiting. The second study used 90 steers (243 +/- 18 kg) supplemented with BM plus incremental amounts of SAA from either FTH or rumen-protected Met. Addition of SAA improved ADG compared with BM alone (P < .05). Rumen-protected Met as a source of SAA improved ADG compared with FTH (P < .05). The SAA from FTH promoted a gain response equal to 50% of the response obtained with rumen-protected Met. Formulation of ruminant diets for metabolizable amino acids must account for escape value and digestibility of each individual amino acid. Feather meal is an effective source of SAA; however, Cys supplies over five times the amount supplied by Met.

The effect of infusion of urea into the vena cava on feed intake of finishing gilts

Three experiments were conducted to evaluate the relationship between feed intake and plasma urea concentration. In Exp. 1, six gilts (BW 53 kg) with catheters in their venae cavae were used in a 5x5+1 Latin square design to determine the amount of infused urea needed to mimic the plasma urea concentration of pigs fed a 25% CP diet. Five gilts were fed a 16% CP corn-soybean meal diet and were infused continuously with either saline or one of four doses of urea (6, 12, 18, and 24 g/d) during each of five periods (12 h/period). Between periods, infusions were stopped for 36 h. The sixth pig was fed a 25% CP diet and infused with saline during each of the experimental periods. Venous blood samples were obtained at 1-h intervals starting 1 h before infusion. As expected, plasma urea concentration increased with increasing amount of urea infused. A daily infusion of 24 g of urea resulted in a plasma urea concentration similar to that of the pig fed the 25% CP diet with saline infusion. In Exp. 2, 12 gilts (BW 60 kg) were used in a crossover design. Pigs received a 16% CP diet and a different treatment (saline or 24 or 30 g/d of urea) in each of three infusion periods. Each infusion period lasted 2 wk. Infusions were stopped for 2 d between periods. Blood samples were obtained before infusion and daily after infusions started. Feeders were weighed daily to determine ADFI. Experiment 3 was similar to Exp. 2, except that only two treatments (saline and 30 g/d of urea) were used. Data from Exp. 2 and 3 were combined for statistical analysis. Plasma urea concentration increased linearly (P<.001) with increasing amount of urea infused. Overall, there was a trend (P<.10) for urea infusion to decrease ADFI, and pigs infused with 30 g/d consumed less (P<.05) feed than pigs infused with saline. Therefore, plasma urea concentration may play a role in regulating feed intake in gilts consuming excess protein.

Variability among sources and laboratories in nutrient analyses of corn and soybean meal. NCR-42 Committee on Swine Nutrition. North Central Regional-42

A cooperative research study involving members of a regional committee (North Central Regional Committee on Swine Nutrition [NCR-42]) was conducted to assess the variability in nutrient composition (DM, CP, Ca, P, Se, and amino acids) of corn and soybean meal from 16 sources (15 states, mostly in the Midwest) and to assess the analytical variability in nutrient assays among 22 laboratories (labs; 16 experiment station labs and six commercial labs). Corn samples were obtained from each participating station's feed mill during a 3-yr period (1989, 1990, and 1992), as were soybean meal samples during a 2-yr period (1989 and 1990). Both regular soybean meal (with hulls) and dehulled soybean meal were represented in the study. Samples were analyzed for DM and CP by all 22 labs, for Ca and P by 15 labs, for amino acids by 10 labs, and for Se by 6 labs. Each lab used its own analytical procedures. Samples of corn and soybean meal varied in their nutrient composition depending on the area of origin. The greatest variation among sources was in Se concentration, ranging from .02 to .29 mg/kg in corn and .08 to .95 mg/kg in soybean meal. Crude protein and lysine in corn were positively correlated, but the regression coefficient was low (r2 = .49). The relationship between CP and lysine for the two soybean meals combined was considerably stronger (r2 = .81). Lysine in corn increased by .018 percentage point and lysine in soybean meal (regular and dehulled combined) increased by .063 percentage point for each 1 percentage point increase in CP. Except for CP and Se, the analytical variability among labs was as great as, and in some cases greater than, the variability in nutrient composition among sources of corn and soybean meal. Within-lab analytical variability tended to be less than among-lab variability. Some labs performed certain analyses with considerably less variability and more accuracy than others.

The effect of excess protein on growth performance and protein metabolism of finishing barrows and gilts

Two experiments were conducted to evaluate the effect of excess protein on growth performance, carcass characteristics, organ weights, plasma urea concentration, and liver arginase activity of finishing barrows and gilts. In Exp. 1, 35 barrows and 35 gilts with an initial BW of 51 kg were used. Five pigs of each sex were slaughtered at the start of the study to determine initial body composition. The remaining 60 pigs were allotted to a randomized complete block (RCB) experiment with a 2x5 factorial arrangement of treatments (two sexes x five protein levels: 13, 16, 19, 22, and 25% CP). The experiment continued until the average BW was 115 kg, at which time three blocks of pigs (30 total) were selected randomly and slaughtered. Feed intake decreased with increasing protein concentration (linear, P<.05), and the reduction was greater in gilts than in barrows (P<.05). There was a trend toward a linear negative effect of dietary protein on ADG (P<.10) and also a quadratic effect of protein on protein accretion (P<.10). Fat accretion decreased linearly as protein level increased (P<.05). Increased protein concentrations increased liver, kidney, and pancreas weights (linear, P<.05). Plasma urea concentration increased with each protein concentration, with the exception of the 25 vs. 22% CP treatment in gilts. In Exp. 2, 18 barrows and 18 gilts (BW 63 kg) were allotted to an RCB design consisting of a 2x2 factorial arrangement of treatments with two sexes and two dietary protein concentrations (16 and 25% CP). The experiment was terminated when the average BW of pigs reached 105 kg. Average daily feed intake was greater (P<.10) in barrows than in gilts. Average daily gain was reduced by 18% in gilts when dietary protein was increased from 16 to 25% but was only reduced 3% in barrows (sex x protein, P<.10). Barrows had lighter livers (P<.005), greater arginase activities (P<.05), and greater plasma urea concentrations (P<.005) than did gilts. Increasing dietary protein concentration from 16 to 25% increased liver weight, arginase activity, and plasma urea concentration (P<.005). These data suggest that gilts are more sensitive than barrows to excessive intakes of protein. The more negative effects in gilts may be related to liver metabolic capacity and activity of urea cycle enzymes.

Addition of fat to the diets of lactating sows: II. Effects on hormone-sensitive lipase activity, energy mobilization in response to epinephrine, and plasma insulin and glucose concentrations

Four experiments were conducted to determine the effects of dietary fat on lipolysis in lactating sows. In Exp. 1, a 6 x 6 Latin square was used to determine the optimal dosage of epinephrine for use in a subsequent epinephrine challenge. Peak concentrations of plasma glucose and response area increased linearly (P < .10) with epinephrine dosage. However, plasma NEFA peak and response area were quadratically affected (P < .05 and .06, respectively) by epinephrine dosage, with a minimum NEFA peak concentration observed at .4 microg/kg and a maximum at 1.6 microg/kg. In Exp. 2, the effect of dietary tallow on the response to epinephrine infusion (1.6 microg/kg BW) was examined. No differences (P > .10) between treatments were observed in NEFA, glycerol, or peak concentrations of plasma glucose following epinephrine administration. In Exp. 3, the effect of dietary fat on hormone-sensitive lipase activity was examined. Sows (n = 36) were fed diets containing either 0 or 10% added tallow. Hormone-sensitive lipase activity on d 28 of lactation was increased by the addition of tallow to the diet (P = .06). No effect of dietary tallow was observed on hormone-sensitive lipase activity of adipose tissue on d 21 of lactation (P > .10) in Exp. 3 (n = 16 sows) and Exp. 4 (n = 30 sows). In summary, diets containing 10% added tallow did not alter the rate of lipolysis, as measured by exogenous epinephrine challenge, in adipose tissue of lactating sows.

Addition of fat to the diets of lactating sows: I. Effects on milk production and composition and carcass composition of the litter at weaning

In Exp. 1 two groups of 18 sows were used to evaluate the effects of supplemental dietary fat on sow and litter performance and milk production and composition. Sows were provided ad libitum access to either a corn-soybean meal (control) diet or a similar diet containing 10% tallow. Feed intake, ME intake, and milk yield did not differ (P > .10) between treatments. The percentage of solids in milk was greater (P < .05) for sows fed the tallow diet, due to an increase (P < .05) in the fat and ash content. Compared with percentages of fatty acids in milk of sows fed the control diet, the percentages of C10:0, C14:0, C16:0, C16:1, and C18:3 fatty acids were lower (P < .05) and the percentages of C18:0 and C18:1 fatty acids were higher in milk of sows fed tallow diets (P < .05). In Exp. 2, 30 sows were fed diets similar to those fed in Exp. 1, and the effects of a tallow diet on pig carcass composition at weaning were determined. Litter size was standardized to 10 pigs. There were no differences (P > .10) in ADFI of sows. Daily ME intake was greater for sows fed tallow than for control sows during wk 2 (P < .05), wk 3 (P < .10), and the entire lactation (P < .05) period. Litter weaning weight was greater (P < .05) for pigs from sows fed tallow diets than for pigs from control sows. Pigs from tallow-fed sows had greater carcass fat weight and fat percentages (P < .05) and lower water and protein percentages (P < .05). These data indicate that the increased fat content of milk from sows fed tallow diets resulted in an increased weight gain for litters nursing these sows. The composition of the increased weight gain is almost exclusively fat.

New targets for anti-inflammatory drugs

Inflammatory and autoimmune diseases, including rheumatoid arthritis, inflammatory bowel diseases, multiple sclerosis, psoriasis and asthma, provide drug discoverers with a tremendous challenge. The precise causes of these diseases are not known, but our understanding of the molecular and cellular mechanisms associated with inflammatory diseases has increased dramatically. As a consequence, a wide array of gene targets have emerged that control cell influx and activation, inflammatory mediator release and activity, and tissue proliferation and degradation. Since multiple gene products have been identified at the sites of inflammation, there has been a surge of interest in identifying intracellular signaling targets, including transcription factors that control inflammatory gene expression and which are amenable to drug discovery.

Effect of immune priming on Borna disease

Borna disease virus (BDV) is a neurotropic virus with a broad host and geographic range. Lewis rats were immunized against BDV with a recombinant vaccinia virus expressing the BDV nucleoprotein and were later infected with BDV to evaluate protection against Borna disease (BD). Relative to animals that were not immunized, immunized animals had a decreased viral burden after challenge with infectious virus, more marked inflammation, and aggravated clinical disease. These data suggest that a more robust immune response in Borna disease can reduce viral load at the expense of increased morbidity.

Bioactivation of the cooked food mutagen N-hydroxy-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine by estrogen sulfotransferase in cultured human mammary epithelial cells

Cooked food mutagens from fried meat and fish have recently been suggested to contribute to the etiology of breast cancer. Thus, the most prevalent of these compounds, i.e. 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, or rather its more mutagenic N-hydroxylated metabolite (N-OH-PhIP), forms DNA adducts in mammary cells, including human mammary epithelial (HME) cells. The objective of this study was to determine the involvement of estrogen sulfotransferase (EST), the only sulfotransferase identified in HME cells, in the further bioactivation of N-OH-PhIP. These studies were done in vitro using human recombinant EST and in intact HME cells. Human recombinant EST increased the covalent binding of [3H]N-OH-PhIP to calf thymus DNA approximately 3.5-fold in the presence of the sulfotransferase co-substrate 3'-phosphoadenosine-5'-phosphosulfate at each N-OH-PhIP concentration (1, 10 and 100 microM) (n = 6, P < 0.001). In contrast, EST did not catalyze the DNA binding of two other cooked food mutagens, N-hydroxy-2-amino-3-methylimidazo[4,5-f]quinoline and N-hydroxy-2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, which are mainly hepatocarcinogens. Cultured HME cells displayed high EST activity, which could be completely inhibited by 1 microM estrone. When the cells were incubated with [3H]N-OH-PhIP, binding to native DNA occurred at 60-240 pmol/mg DNA. This binding was inhibited to 55% of control by 1 microM estrone (P < 0.01, n = 8), suggesting that EST plays a significant role in carcinogen bioactivation in human breast tissue.