Complementary responses between feather meal and poultry by-product meal with or without ruminally protected methionine and lysine in growing calves

We evaluated feather meal (FTH) and poultry by-product meal (PBM) as complementary protein sources for growing calves. In a replicated 84-d growth trial, individually fed steer calves (n = 120; 252 +/- 24 kg) were supplemented with urea or with graded levels of soybean meal (SBM), FTH, PBM, or 2/3 FTH:1/3 PBM (CP basis). Protein efficiency, calculated as gain above the urea control vs natural protein intake using the slope-ratio technique, was greater for FTH than for SBM, PBM, and 2/3 FTH:1/3 PBM (P < .10). Addition of ruminally protected methionine and lysine did not affect protein efficiency (P > .30) for FTH, PBM, or 2/3 FTH:1/3 PBM. Even though true protein digestibility in the gastrointestinal tract in a trial with lambs was similar (P > .15) for FTH (83.1%) and PBM (91.2%), escape protein was greater for FTH (66.8%) than for PBM (43.6%). Analyses were conducted to estimate intestinal flow of amino acids relative to requirements for live animal gain, and no obvious amino acid deficiencies were present. The lack of a response in protein efficiency to ruminally protected methionine and lysine suggests that FTH and PBM are adequate in these amino acids. Although FTH and PBM are excellent sources of metabolizable protein, there was no complementary response in protein efficiency between them.

Effects of the reproductive cycle and age on calcium and phosphorus metabolism and bone integrity of sows

The purpose of this study was to determine the effects of stage of the reproductive cycle and age on Ca and P metabolism and bone integrity of sows. Five-day balance studies were conducted with first- and fifth-parity sows, and sows were slaughtered during the last trimester of gestation, at the end of lactation, or during the last trimester of the subsequent gestation. First-parity sows were studied during their first gestation (n = 11), first lactation (n = 10), or second gestation (n = 10). Fifth-parity sows were examined during their fifth gestation (n = 10), fifth lactation (n = 9), or sixth gestation (n = 9). All sows were fed 1.9 kg/d of a common diet (.76% Ca and .63% P) during gestation and were allowed ad libitum access to the same diet during lactation. Digestibilities of Ca and P were much greater during lactation than during gestation. During gestation, young sows absorbed and retained more Ca and P than did mature sows. However, during lactation, mature sows consumed more feed, and therefore Ca and P, and retained more Ca and P than did young sows. Bones of mature sows were larger, more mineralized, and stronger than the bones of young sows. Bone weight and strength decreased during lactation and increased during the subsequent gestation. Changes in weight and strength were greater in young sows than in mature sows.

Fertility control as a means of controlling bovine tuberculosis in badger (Meles meles) populations in south-west England: predictions from a spatial stochastic simulation model

A spatial stochastic simulation model was used to assess the potential of fertility control, based on a yet-to-be-developed oral bait-delivered contraceptive directed at females, for the control of bovine tuberculosis in badger populations in south-west England. The contraceptive had a lifelong effect so that females rendered sterile in any particular year remained so for the rest of their lives. The efficacy of fertility control alone repeated annually for varying periods of time was compared with a single culling operation and integrated control involving an initial single cull followed by annually repeated fertility control. With fertility control alone, in no instance was the disease eradicated completely while a viable badger population (mean group size of at least one individual) was still maintained. Near eradication of the disease (less than 1% prevalence) combined with the survival of a minimum viable badger population was only achieved under a very limited set of conditions, either with high efficiency of control (95%) over a short time period (1-3 years) or a low efficiency of control (20%) over an intermediate time period (10-20 years). Under these conditions, it took more than 20 years for the disease to decline to such low levels. A single cull of 80% efficiency succeeded in near eradication of the disease (below 1% prevalence) after a period of 6-8 years, while still maintaining a viable badger population. Integrated strategies reduced disease prevalence more rapidly and to lower levels than culling alone, although the mean badger group size following the onset of control was smaller. Under certain integrated strategies, principally where a high initial cull (80%) was followed by fertility control over a short (1-3 year) time period, the disease could be completely eradicated while a viable badger population was maintained. However, even under the most favourable conditions of integrated control, it took on average more than 12 years following the onset of control for the disease to disappear completely from the badger population. These results show that whilst fertility control would not be a successful strategy for the control of bovine tuberculosis in badgers if used alone, it could be effective if used with culling as part of an integrated strategy. This type of integrated strategy is likely to be more effective in terms of disease eradication than a strategy employing culling alone. However, the high cost of developing a suitable fertility control agent, combined with the welfare and conservation implications, are significant factors which should be taken into account when considering its possible use as a means of controlling bovine tuberculosis in badger populations in the UK.

Limiting amino acids in meat and bone and poultry by-product meals

In situ, digestion, and growth studies were conducted to evaluate four meat and bone meals and six poultry by-product meals as sources of escape protein and to predict the first-limiting amino acid for growing calves. Escape protein values, determined by 12-h in situ incubation, ranged from 41.7 to 51.0% of CP for meat and bone meals; poultry by-product meals ranged from 32.0 to 39.8%. True protein digestion in the gastrointestinal tract of lambs differed among protein sources (P < .05), ranging from 79 to 95%. In each of three growth trials, 60 steers (258 +/- 24, 241 +/- 23, and 230 +/- 16 kg for Trials 1, 2, and 3, respectively) were supplemented with 4 of the 10 protein sources along with a urea supplement. Protein sources were fed at 30, 40, 50, and 60% of the supplemental CP, with urea supplying the remainder. Protein efficiency differed among treatments ( P < .10), ranging from .61 to 1.55. Amino acid composition was determined for each protein source, and the individual metabolizable amino acids were regressed on the protein efficiency values. Escape protein values were correlated (R2 = .75) with protein efficiency but had a negative slope. Metabolizable methionine was the only amino acid moderately correlated (R2 = .40, slope = 1.9) to protein efficiency, whereas other amino acids either correlated poorly or had negative slopes. These data indicate that the protein value of meat and bone meal and poultry by-product meal is limited by the amount of metabolizable methionine they contain.

Addition of ruminal escape methionine and lysine to meat and bone meal

A growth study was conducted to determine the effects of adding ruminal escape methionine and lysine to meat and bone meal (MBM). A basal diet of 44% sorghum silage, 44% corncobs, and 12% supplement (DM basis) was individually fed to 60 crossbred steers (234 +/- 14 kg). Supplements contained either urea, MBM, MBM plus protected methionine (MBM + M), or MBM plus protected methionine and lysine. Protein sources were fed to supply 30, 40, 50, and 60% of the supplemental CP, with urea supplying the remainder. Protein efficiency, calculated as gain above the urea control vs natural protein intake using the slope ratio technique, was used to evaluate the protein sources. The most efficiently used protein source was MBM + M, which was greater than MBM alone (P < .10). Meat and bone meal plus protected methionine and lysine had a protein efficiency similar to MBM + M (P > .30), indicating that lysine was not limiting. True protein digestibility of MBM in the gastrointestinal tract of lambs was determined to be 86.1%. In situ analysis performed by 12-h ruminal incubation of MBM determined the escape CP to be 53.0% of CP. Amino acid analysis was conducted to compare supplies to requirements for live animal gain. The urea control failed to meet the metabolizable protein requirement. Feeding MBM to provide additional metabolizable protein failed to provide an adequate amount of the essential amino acid methionine, which was first-limiting. These data indicate that protein efficiency of MBM can be enhanced by the addition of ruminal escape methionine.

Estimation of relative bioavailability of nutrients using SAS procedures

The General Linear Models procedure (PROC GLM) in SAS/STAT software can be programmed to perform the standard statistical analyses used for relative bioavailability studies. The first steps are validity checks to test for statistical validity (linearity), fundamental validity (intersection of regression lines at 0 supplemental level), and equality of the basal diet mean to the point of intersection. The CLASS variable capabilities of PROC GLM can be exploited to expedite these tests. After the validity checks, the GLM procedure can be used to obtain parameter estimates for calculation of relative bioavailability. Optional output provides an inverse matrix to calculate standard errors of slopes and slope ratios. Logarithmic and other transformations of the dependent variable to reduce variance heterogeneity or achieve linearity for subsequent calculation of appropriate bioavailability values also can be accomplished within the SAS System. When nonlinear regression models are more appropriate than linear models, the NLIN procedure can be used.

Borna disease

Borna disease virus, a newly classified nonsegmented negative-strand RNA virus with international distribution, infects a broad range of warm-blooded animals from birds to primates. Infection causes movement and behavioral disturbances reminiscent of some neuropsychiatric syndromes. The virus has not been clearly linked to any human disease; however, an association between infection with the virus and selected neuropsychiatric disorders has been suggested. We reviewed recent advances in Borna disease virus research, focusing on evidence of infection in humans.

Biochemical and functional analysis of the Borna disease virus G protein

The Borna disease virus (BDV) antigenome is comprised of five major open reading frames (ORFs). Products have been reported only for ORFs I, II, and III, encoding N (p40), P (p24/p23), and M (gp18), respectively. ORF IV predicts a 57-kDa protein with several potential glycosylation sites. Analysis of radiolabeled extracts from BDV-infected C6 cells and BHK-21 cells transfected with a Semliki Forest virus vector that contains ORF IV demonstrated the presence of a 94-kDa protein (G protein) which was sensitive to tunicamycin, endoglycosidase F/N-glycosidase, and endoglycosidase H but not to O-glycosidase. Sera from BDV-infected rats detected the G protein and had neutralization activity that was reduced following immunoadsorption with the G protein. Preincubation of cells with the G protein interfered with BDV infectivity. This effect was enhanced by treatment of the G protein with the exoglycosidase alpha-mannosidase and reduced after subsequent treatment with N-acetyl-beta-D-glucosaminidase. In concert these findings indicate that ORF IV encodes a 94-kDa N-linked glycoprotein with extensive high mannose- and/or hybrid-type oligosaccharide modifications. The presence of neutralization epitopes on the G protein and its capacity to interfere with infectivity suggest that the G protein is important for viral entry.

Improved bacterial expression of the human P form phenolsulfotransferase. Applications to drug metabolism

Bacterial expression of human phenol phenolsulfotransferase (P-PST) has provided the opportunity to understand better the catalytic properties and biological role of this enzyme. However, as the yield of pure protein from the currently used expression system was low, we subcloned the P-PST c-DNA into pET-15b, a vector containing an oligohistidine domain, for improved expression. The fusion protein, His-P-PST, was isolated from the bacterial cytosol in a single affinity chromatography step, using a Ni2+ agarose column. The yield of His-P-PST from the pET-15b vector was improved 12-fold, compared with P-PST from the original vector. The purity was > 99%, as established by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and densitometry scanning. The enzyme was stable for at least 3 weeks when stored in 20% glycerol at -80 degrees C. A very rapid deterioration of the enzyme during 37 degrees C incubations was effectively prevented by the addition of bovine serum albumin. The sulfonation of several substrates was very similar for His-P-PST and P-PST, with Vmax/KM values (first order rate constants) for the high-affinity substrate p-nitrophenol of 143 +/- 27 and 120 +/- 25 ml min-1 microgram-1 PST [mean +/- SE; not significant (NS)], respectively, and for the low-affinity substrate acetaminophen of 0.21 +/- 0.11 and 0.14 +/- 0.07 ml min-1 microgram-1 PST (NS). The Vmax/KM for the sulfonation of the isoproterenol enantiomers showed a (+)/(-)-enantiomer ratio of 6.2 for His-P-PST and 7.4 for P-PST. Interestingly, 3- to 10-fold higher apparent KM values were obtained for these substrates with the crude human liver cytosol, compared with the recombinant P-PSTs, suggested to be due to endogenous or dietary P-PST inhibitors in the liver. In addition, the inhibition of acetaminophen sulfonation by quercetin was very similar for His-P-PST and P-PST, with IC50 values of 0.10 +/- 0.03 and 0.05 +/- 0.01 microM (NS), respectively. The additional amino acid residues in the His-P-PST, compared with the recombinant P-PST, thus did not significantly alter the catalytic properties. This bacterial expression system should lend itself to routine use in studies of the metabolism of drugs and environmental chemicals.

Narcolepsy secondary to fourth ventricular subependymoma

BACKGROUND

Secondary (symptomatic) narcolepsy is rare. We report a subependymoma of the fourth ventricle associated with narcolepsy. The patient was a 50-year old woman with a long history of narcolepsy who died of colonic carcinoma with no cerebral metastasis. She was positive for HLA-DR2. At autopsy there was a tumour dorsal to the fourth ventricle which involved the midbrain tectum and rostral pons. Histologic examination of the tumour confirmed it to be a subependymoma.

METHODS

Review of the previous cases of secondary narcolepsy was made with particular reference to the anatomical location of the lesions.

RESULTS

Most of the lesions were found around the third ventricle and rostral brainstem.

CONCLUSIONS

Knowing the anatomical localization of the pathological changes in secondary narcolepsy could be important in improving our understanding of its pathogenesis.

Flavonoids, potent inhibitors of the human P-form phenolsulfotransferase. Potential role in drug metabolism and chemoprevention

The common dietary constituent quercetin was a potent inhibitor of sulfoconjugation of acetaminophen and minoxidil by human liver cytosol, partially purified P-form phenolsulfotransferase (PST), and recombinant P-form PST, with IC50 values of 0.025-0.095 microM. Quercetin inhibition of acetaminophen was noncompetitive with respect to acceptor substrate, with a Ki value of 0.067 microM. A number of other flavonoids, such as fisetin, galangin, myricetin, kaempferol, chrysin, and apigenin, were also potent inhibitors of P-form PST-mediated sulfation, with IC50 values < 1 microM. Studies of structural analogs indicated the flavonoid 7-hydroxyl group as particularly important for potent inhibition. Potential human metabolites of quercetin were poor inhibitors. Curcumin, genistein, and ellagic acid (other polyphenolic natural products) were also inhibitors of P-form PST, with IC50 values of 0.38-34.8 microM. Quercetin was also shown to inhibit sulfoconjugation by the human hepatoma cell line Hep G2. Although less potent in this intact cell system (IC50 2-5 microM), quercetin was still more potent than 2,6-dichloro-4-nitrophenol, the classical P-form PST inhibitor that has been shown to be an inhibitor also in vivo. These observations suggest the potential for clinically important drug interactions, as well as a possible role for flavonoids as chemopreventive agents in sulfation-induced carcinogenesis.

The effects of dietary protein concentration on compensatory growth in barrows and gilts

An experiment using 120 crossbred pigs (60 barrows and 60 gilts) was conducted to determine the effect of dietary protein concentration on the compensatory response in growth after a period of feed restriction. Thirty pigs were allowed ad libitum (AL) access to one of five corn-soybean meal diets (13.1 to 18.4% CP) from approximately 42 to 102 kg BW. Thirty additional pigs were restricted (R) to a maintenance amount of a 14.4% CP diet for 21 d, after which they were allotted to one of the five diets and allowed ad libitum access to feed until they reached 102 kg. Restricted pigs had lower ADFI, ADG, and ADG/ADFI (P < .05) than did AL pigs. During the postrestriction period, R pigs had higher ADFI and ADG (P < .001) and tended to be more efficient (P < .08) than AL pigs. Average backfat thickness was not different (P > .8) between AL and R pigs. Lean percentage (5% fat) was not affected (P > .5) by feeding regimen but increased linearly (P < .1) as protein level increased. Organ weights (expressed as a percentage of empty BW.75) were similar in AL and R pigs. However, kidney and stomach weights differed among protein levels (P < .01), as did liver weight (P < .06), with a linear increase (P < .02) in both kidney and liver weights to dietary protein level. Barrows had higher ADFI and ADG and greater average backfat thickness (P < .02) than gilts. Barrows had smaller LMA, a lower percentage of lean (P < .001), and higher average backfat (P < .005) than gilts. Liver weight was heavier (P < .02) and small intestine weight tended to be heavier (P < .07) for barrows than for gilts. Kidney, spleen, and lungs were heavier (P < .05) in gilts than in barrows. Livers from barrows tended to contain more protein (P < .06) and less fat (P < .05) than livers from gilts. These results indicate that a compensatory growth response occurred during relimentation, and that the effects of dietary protein concentration on growth rate and carcass measurements were similar in both AL and R pigs.

Changes in plasma urea concentration can be used to determine protein requirements of two populations of pigs with different protein accretion rates

The experiment had two objectives: 1) to determine the protein requirements of two strains of growing-finishing pigs based on growth performance, carcass characteristics, tissue accretion rates, and organ weights and 2) to evaluate whether protein requirements can be determined from changes in plasma urea concentration. Forty-six Gene Pool (GP) and 46 Hampshire (H) gilts with an initial BW of 28.5 kg were used. Pigs were allotted to two trials of a randomized complete block experiment with a 2 x 6 factorial arrangement of treatments. Five pigs from each strain were randomly selected and slaughtered at the beginning of each of the two trials. The remaining 72 pigs were individually penned and allotted to one of six dietary treatments (10, 13, 16, 19, 22, or 25% CP). Pigs remained on the experiment until the mean weight of a treatment group within each strain reached 115 kg (16 wk for GP and 14 wk for H), at which time all pigs of that strain were slaughtered. The only strain x protein level interactions that were detected were for carcass protein and water accretion rates. Gene Pool pigs grew less rapidly and utilized feed less efficiently than H pigs (P < .001). Average daily gain (quadratic, P < .05) and ADG/ADFI (quadratic, P < .05) were increased as protein level increased until a plateau was reached. Backfat depths were decreased (linear, P < .001) and longissimus muscle areas were increased (linear, P < .001) as protein level increased. Protein accretion rate was lower (P < .01) and fat accretion was higher (P < .01) in GP pigs than in H pigs. Protein accretion increased (quadratic, P < .001) and fat accretion decreased (linear, P < .001) with increasing dietary protein level. Examination of the response of plasma urea concentration over time suggested that GP pigs required 13% CP from 30 to 80 kg and 10% CP thereafter, whereas H pigs required 19% CP from 30 to 45 kg, 16% CP from 45 to 100 kg, and 13% CP thereafter.

Valine requirement of the finishing pig

Pigs weighing approximately 70 kg were used in two experiments to determine the valine requirement during the finishing period. In the first experiment, 10 gilts were allotted in two 5 x 5 Latin square designs to five semipurified diets that ranged in valine concentration from .35 to .55%. Urinary urea excretion was measured during each of the 3-d periods of the Latin square. Urea N excretion in relation to N intake and to creatinine N excretion was minimized (quadratic effect, P < .10) at valine concentrations of .45 to .50%. In Exp. 2, 36 barrows and 36 gilts were fed one of six diets containing .35 to .60% valine. The highest weight gains (not significant) and feed efficiencies (quadratic effect, P < .05) were achieved by the pigs that consumed .45% valine. Plasma urea concentration at the end of the experiment was lowest (quadratic effect, P < .05) in pigs that consumed .50% valine. Estimates of the valine requirement based on breakpoint and quadratic equation analyses ranged from .40 to .50% total valine (.33 to .43% ileal digestible valine). Pigs in Exp. 2 consumed approximately 2.5 kg/d (8,850 kcal/d of ME). Thus, the estimate of the valine requirement is approximately 11 g/d. These estimates of the valine requirements of finishing pigs are slightly higher than the National Research Council requirements when expressed as a percentage of the diet but are similar when expressed on a grams per day basis.

Acceleration of experimental lapine osteoarthritis by calcium pyrophosphate microcrystalline synovitis

OBJECTIVE

To investigate the effects of chronic calcium pyrophosphate dihydrate (CPPD) synovitis on the development of osteoarthritic (OA) lesions in an animal model.

METHODS

OA was induced in the right knees of 30 male New Zealand white rabbits by partial lateral meniscectomy and section of the fibular collateral and sesamoid ligaments (PLM/LS), followed by 8 weekly intraarticular (IA) injections of 1 mg (low-dose) or 10 mg (high-dose) of CPPD crystals in 3 sets of experiments (10 rabbits each). The contralateral left knees served as controls: experiment 1 PLM/LS alone, experiment 2 8 weekly IA injections of CPPD crystals alone, and experiment 3 sham surgery plus 8 weekly IA injections of CPPD crystals.

RESULTS

At 8 weeks, repeated IA injections of low-dose and high-dose CPPD crystals into meniscectomized right knees resulted in more severe OA than in meniscectomized but noninjected left knees (experiment 1) (P = 0.003 and P = 0.001, respectively). One-fourth of the meniscectomized knees (11 of 40), both CPPD-injected and noninjected, showed embedded synovial cartilage shards.

CONCLUSION

The data demonstrate a worsening effect of chronic CPPD crystal-induced synovitis on experimental OA produced in the rabbit knees by PLM/LS, and support a possible role for CPPD microcrystalline inflammation in the progression of OA lesions in clinical CPPD crystal deposition disease.

Bioavailability of zinc from inorganic and organic sources for pigs fed corn-soybean meal diets

Two experiments were conducted with pigs 1) to determine the effect of supplemental Zn on growth performance, bone Zn, and plasma Zn in pigs fed Zn-unsupplemented, corn-soybean meal diets and 2) to assess bioavailability of Zn from inorganic and organic Zn sources. In both experiments, weanling pigs were fed a diet with no supplemental Zn for 5 wk to deplete their Zn stores. In Exp. 1, 192 pigs were fed a corn-soybean meal diet (growing diet, 32 mg/kg of Zn; finishing diet, 27 mg/kg of Zn) supplemented with feed-grade ZnSO4.H2O to provide 0, 5, 10, 20, 40, and 80 mg/kg of supplemental Zn. Supplemental Zn did not affect weight gain, feed intake, or gain/feed during either the growing or the finishing period (P > .05). However, bone and plasma Zn concentrations increased linearly (P < .01) in response to supplemental Zn at dietary Zn levels between 27 mg/kg (basal) and 47 mg/kg (breakpoint). In Exp. 2, three levels of supplemental Zn from ZnSO4.H2O (0, 7.5, and 15 mg/kg of supplemental Zn) were used to construct a standard curve (metacarpal, coccygeal vertebrae, and plasma Zn concentrations regressed on supplemental Zn intake; R2 = .93, .89, and .82, respectively). From the standard curve, the bone and plasma Zn concentrations obtained from pigs fed 15 mg/kg of supplemental Zn from ZnO and 7.5 mg/kg of supplemental Zn from Zn-methionine (ZnMET) and Zn-lysine (ZnLYS) were used to calculate bioavailable Zn via multiple linear regression, slope-ratio analysis. The estimates of Zn bioavailability differed depending on which variable was used. Overall trends indicated the following rankings: ZnSO4.H2O > ZnMet > ZnO > ZnLys.

The effect of protein intake on boar libido, semen characteristics, and plasma hormone concentrations

To determine the effect of low protein intake on boar libido, semen characteristics, and plasma hormone concentrations, 20 crossbred boars (1 yr of age) were divided into 10 littermate pairs, and boars from within pairs were fed 44 g/kg of BW.75 per day of either a low-protein diet (7% CP) or a control diet (16% CP) with the same energy content (3.41 Mcal of ME/kg). During the first 16 wk and from wk 19 to 23, semen was collected two times per week. During wk 17 and 18, boars were subdivided within dietary treatment and semen was collected either two or seven times per week. Blood samples were collected at 12-min intervals for 6 h before and 1 h after an intravenous injection of GnRH (375 ng/kg of BW) during wk 24. All plasma samples were analyzed for LH and pooled samples were analyzed for estradiol-17 beta and testosterone. Boars with low protein intakes required more time to start ejaculation (P = .11, wk 0 through 7; P < .04, after wk 7), had a shorter duration of ejaculation (P < .09, wk 19 through 23), and had reduced semen volumes (P < .01, after wk 7) compared with boars on the control treatment. There was no interaction between dietary treatment and semen collection frequency (P > .39) for any of the semen or libido measurements. Testosterone and LH concentrations were not affected by protein intake (P > .5). However, concentration of estradiol-17 beta was greater in boars fed the control diet than in boars fed the low-protein diet (582 vs 202 pg/mL, respectively; P < .08). Estrogen concentrations in boars were negatively correlated with the time required for the boar to start ejaculating (r2 = .72). Boars with low protein intakes had reduced libido and semen volume. This reduction in libido and semen volume may be a result of a decrease in estradiol-17 beta concentration in circulation.

The effect of energy and protein intakes on boar libido, semen characteristics, and plasma hormone concentrations

To determine the effect of energy and protein intakes on boar libido, semen characteristics, and plasma hormone concentrations, 24 crossbred boars (1 yr of age) were allotted to one of three dietary treatments. Two protein levels (7.7 and 18.1 g/d of lysine) and two energy levels (6.1 and 7.7 Mcal/d of ME) were combined to create 1) low-energy and low-protein (ep), 2) low-energy and high-protein (eP), and 3) high-energy and high-protein (EP) treatments. Semen was collected two times per week for 27 wk. During wk 28, blood samples were collected before and after a intravenous injection of GnRH (375 ng/kg of BW). The EP boars had higher (P < .01) ADG than the eP boars (373 vs 169 g), which had higher (P < .01) ADG than the ep boars (169 vs 92 g). Fewer EP and eP boars (zero of eight and two of eight, respectively) than ep boars (five of eight) consistently refused to mount the collection dummy (P < .05). During the final 20 wk of the semen-collection period, EP and eP boars had 33% longer durations of ejaculation (P < .04), had 60% greater semen and gelatinous fraction volumes (P < .03), but had 25% lower sperm concentration in their semen (P < or = .12) than ep boars. The EP boars produced 38% more sperm than the ep boars (P < .10). Baseline LH concentration, LH pulse frequency, LH pulse amplitude, testosterone concentration, and estradiol-17 beta concentrations were not affected by treatment (P > .10).(ABSTRACT TRUNCATED AT 250 WORDS)

Diet preference and meal patterns of weanling pigs offered diets containing either spray-dried porcine plasma or dried skim milk

Preference tests and meal pattern analyses were conducted to examine the feed intake response of weanling pigs to spray-dried porcine plasma (SDPP). In Exp. 1, 36 weanling pigs (mean +/- SD; 6.2 +/- .8 kg and 26 d of age) were allowed to choose between a SDPP diet (8.5% SDPP, 20% dried whey, 10% lactose, and .13% DL-methionine) and a dried skim milk (DSM) diet (20% each of DSM and dried whey) throughout 21 d postweaning. Twenty-eight pigs preferred the SDPP diet and seven pigs preferred the DSM diet. Preference for SDPP became apparent by d 2 (60% of total feed consumption) and increased (P < .01) to d 21 (71% of total feed consumption). Average daily feed consumption was 371 and 172 g for the SDPP and DSM diets, respectively (P < .01). The meal patterns of 16 weanling pigs (mean +/- SD; 7.2 +/- .3 kg and 26 d of age) offered either the SDPP or the DSM diet were examined in Exp. 2. On d 3, 7, and 14 postweaning, feeding behavior was observed continuously for 18 h (0600 to 2400). Time spent consuming feed and time between periods of feeding were recorded. Although the difference was not significant, pigs fed the SDPP diet consumed 27 and 6% (P = .38) more feed than pigs fed the DSM diet during the first 7 d and during the entire 21-d period, respectively. This difference was reflected in increased (P < .05) rate of feed consumption on d 3 and 7. Diet had no effect (P > .10) on meal size, the number of meals, or the percentage of time spent consuming feed. Weanling pigs prefer diets containing SDPP to those containing DSM, and the increased consumption of diets containing SDPP may be due to greater palatability.

Genomic organization of Borna disease virus

Borna disease virus is a neurotropic negative-strand RNA virus that infects a wide range of vertebrate hosts, causing disturbances in movement and behavior. We have cloned and sequenced the 8910-nucleotide viral genome by using RNA from Borna disease virus particles. The viral genome has complementary 3' and 5' termini and contains antisense information for five open reading frames. Homology to Filoviridae, Paramyxoviridae, and Rhabdoviridae is found in both cistronic and extracistronic regions. Northern analysis indicates that the virus transcribes mono- and polycistronic RNAs and uses termination/polyadenylylation signals reminiscent of those observed in other negative-strand RNA viruses. Borna disease virus is likely to represent a previously unrecognized genus, bornaviruses, or family, Bornaviridae, within the order Mononegavirales.

Postpartum hypophagia in primiparous sows: II. Effects of feeding level during gestation and exogenous insulin on lactation feed intake, glucose tolerance, and epinephrine-stimulated release of nonesterified fatty acids and glucose

The objectives of this experiment were 1) to determine whether allowing sows ad libitum access to feed from d 60 of gestation affects glucose tolerance and 2) to determine whether exogenous insulin increases feed intake by preventing mobilization of nonesterified fatty acids (NEFA). Sixty crossbred sows were assigned to one of two feeding regimens during gestation, either a standard level of feed (SL; 1.85 kg/d) or allowed ad libitum access to feed (AL). Sows also received an injection of either .75 IU of insulin/kg BW or saline daily during the first 7 d of lactation. Exogenous insulin increased ADFI at d 7 of lactation (P = .07) and increased total feed intake at d 7 and 14 of lactation (P = .09). Total feed intake during d 0 to 21 was not affected by insulin treatment. Compared with the SL sows, the AL sows were less tolerant of glucose infusion (1 g of glucose/kg BW, i.v.) on d 1 of lactation (P < .01). Baseline and peak concentrations of insulin were not affected by feeding level during gestation (P = .4). Baseline and peak concentrations of NEFA were greater in AL sows than in SL sows (P < .001) and were not affected by insulin treatment (P = .39). Release of NEFA after epinephrine stimulation was greater in AL sows than in SL sows (P < .05). The data indicate that the reduced feed intake during lactation exhibited by sows that are overfed during gestation may be caused by insulin resistance. Exogenous insulin seems to increase feed intake by reducing plasma glucose rather than be affecting plasma NEFA.

Postpartum hypophagia in primiparous sows: I. Effects of gestation feeding level on feed intake, feeding behavior, and plasma metabolite concentrations during lactation

To investigate the relationship between feeding level during gestation and voluntary feed intake, feeding behavior, and plasma metabolite levels during lactation, 18 crossbred, primiparous sows were assigned to two dietary treatments. From d 60 of gestation until farrowing, sows were fed either a standard level of feed (SL; 1.85 kg/d) or were allowed ad libitum (AL) access to feed. During a 28-d lactation all sows were allowed ad libitum access to feed. Eight SL and seven AL sows completed the experiment. Feed intake was measured daily during the final 40 d of gestation and throughout lactation. On d 105 of gestation and d 1, 7, 14, and 21 of lactation, feeding behavior was observed and blood samples were collected via indwelling catheters. Plasma was analyzed for nonesterified fatty acids (NEFA), insulin, glucose, and alpha-amino N. During gestation AL sows ate more feed than did SL sows. This increased intake was balanced by reduced feed intake during lactation, when AL sows ate less than SL sows (P < .001). The AL sows gained more weight during gestation (P < .001) and lost more weight during lactation (P < .005) than did the SL sows. Feed intake and weight change during gestation and lactation combined were not different between treatments (P = .85). During lactation, the AL sows ate fewer meals (P < .05) of a similar size than did the SL sows. During lactation, the area under the curve formed by plasma NEFA concentration was greater (P = .06) and that for insulin was less (P < .01) in AL than in SL sows.(ABSTRACT TRUNCATED AT 250 WORDS)

Bioavailability of threonine in soybean meal for young pigs

The bioavailability of threonine in solvent-extracted soybean meal for 10- to 20-kg pigs was determined using the slope-ratio method. In Exp. 1, the assay range was determined by feeding six diets to 144 pigs. The basal diet (.40% threonine) contained corn, soybean meal, and corn gluten meal. Five additional diets were formulated by supplementing the basal diet with .05 to .25% crystalline L-threonine in .05% increments. Weight gain, gain/feed, and plasma concentrations of threonine and urea responded quadratically (P < .05) to increasing dietary threonine. Breakpoints ranged from .51 to .54% dietary threonine. Experiment 2 consisted of seven trials in which a total of 239 pigs were used in a randomized complete block design. Pigs were penned individually and had ad libitum access to feed and water during the 21-d experiment. The same basal diet that was used in Exp. 1 was supplemented with .018, .053, or .070% threonine from either L-threonine or soybean meal. The weight gains of the pigs were partitioned to yield the response due to the supplemental threonine ingested. Multiple regression was performed on partitioned weight gain vs supplemental threonine intake, and the assay was tested for validity. The regression lines for L-threonine and soybean meal were linear (P < .05) and the intercepts were not significantly different (P > .10). The slope ratio for soybean meal:L-threonine was .80. Although the difference between the soybean meal and L-threonine slopes was not significant (P > .23), the best estimate of the bioavailability of threonine in soybean meal relative to that of L-threonine was 80%.

Effects of dietary protein concentration (corn:soybean meal ratio) and body weight on nitrogen balance of growing boars, barrows, and gilts: mathematical descriptions

The effects of dietary CP level (actually corn:soybean meal ratio) and BW on N intake, N digestibility, the efficiency of utilization of N (apparent biological value), and N retention were measured in 36 pigs: 12 boars (five collection periods), 12 barrows (four collection periods), and 12 gilts (nine collection periods). Initial and final BW of the boars, barrows, and gilts were 19, 24, and 27 kg and 80, 69, and 110 kg, respectively. Diets were based on corn and soybean meal and contained 11 to 23% CP. Averaged over all collection periods, N retention was 24.2, 20.0, and 19.8 g/d for boars, barrows, and gilts, respectively. The response of N retention to CP levels was quadratic (P < .15) and cubic (P < .01) for boars, linear (P < .01) and quadratic (P < .05) for barrows, and linear (P < .15) for gilts. Rates of N retention responded quadratically (P < .001) for all sexes as pigs gained weight, reaching a maximum when pigs weighed 55 to 65 kg. Multiple-regression analyses were conducted and equations were developed that described the effects of CP level (or lysine intake) and BW on N retention for each sex. The results indicated that N balance was a function of both CP level (or lysine intake) and BW and that the nature of the response differed for each sex.