VTechWorks Repository :: Browsing by Author "Harper, Allen F."

Browsing by Author "Harper, Allen F."

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An assessment of the effects of dietary folic acid supplementation on serum folates status, conceptus development and reproductive performance in gilts and sows
Harper, Allen F. (Virginia Tech, 1992-04-05)
The effects of dietary folic acid supplementation on serum folate status, conceptus development and reproductive performance in gilts and sows was investigated in a series of experiments. The specific objectives of the study were to: 1) to study the serum folates profile following rapid consumption of a single meal containing different levels of supplemental folic acid; 2) to study the effects of maternal folic acid supplementation on conceptus survival, growth and development prior to mid-gestation in gilts and sows; and 3) to study the effects of multiple levels of dietary folic acid supplementation on sow reproductive performance over four successive parities. In the first experiment (Chapter III), gilts fed a single, rapidly consumed meal, had a rapid increase in serum folates concentration during the first hour postprandial. Within eight hours after feeding, serum folates in the gilts had returned to near prefeeding levels. The results also suggest that supplementing the diet with increasing levels of folic acid over a range of 0 to 4 ppm results in more rapid postprandial uptake and elimination of folic acid from general circulation. In the second experiment (Chapter IV), supplementing the diet of first parity and third parity breeding sows with 2 ppm folic acid had no effect on litter size at day 45 of gestation. However, several measurements associated with placental and fetal growth were increased with folic acid supplementation. Results of a fifth parity trial with four levels of supplemental folic acid were variable and inconclusive. The implications of increased placental and fetal growth up to day 45 of gestation in the first and third parity sows is discussed. In the third experiment (Chapter V), a decline in serum folate concentration in pregnant sows from mating to mid- to late gestation was clearly demonstrated. Supplementing the sow's diet with folic acid over a range of 0 to 4 ppm resulted in a linear increase in serum folate concentration at mating, during gestation and at weaning. However, under the conditions of this experiment, folic acid supplementation had no significant effect on sow reproductive performance.
A comparison of virginiamycin and a lactobacillus probiotic as feed additives for swine and the effects of virginiamycin supplementation and crowding stress on swine performance
Harper, Allen F. (Virginia Polytechnic Institute and State University, 1982)
Two experiments were conducted to compare the feedlot performance of swine fed diets containing a commercially available lactobacillus probiotic and virginiamycin, a gram-positive antibiotic (experiment I) and to evaluate the feedlot performance of starter and grower-finisher swine housed under conditions of restricted and adequate space allowance fed diets with and without virginiamycin (experiment II). For experiment I, in four starter trials, pigs fed diets containing virginiamycin tended to eat more and grow faster than pigs fed the control diet while lactobacillus probiotic had no effect on performance. In the combined analysis of a starter-grower-finisher and a grower-finisher trial, virginiamycin supplementation had no effect on performance while the pigs fed the probiotic had significantly poorer gains than the control pigs. In three grower-finisher trials, virginiamycin supplementation improved daily gain and feed consumption while lactobacillus probiotic had no significant effect on performance. For experiment II, in four starter trials, increasing the number of pigs in 1.2 x 1.2 m nursery pens from six to 12 caused significant depressions in final weight, daily gain, feed intake, and feed efficiency. Virginiamycin supplementation significantly improved final weight, daily gain and feed efficiency. In two starter trials, reducing space allowance from .24 to .12 m² per pig caused significant depressions in final weight, daily gain and feed efficiency but virginiamycin had no effect on performance. In a series of grower-finisher trials, decreasing space allowance from .78 to .43 m² pig caused significant depressions in final weight, daily gain, feed intake and feed efficiency while virginiamycin improved feed efficiency. The virginiamycin X space allowance interaction was significant in only one instance with virginiamycin improving feed efficiency 6.2% when starter pigs were given adequate space allowance but only 2.5% when crowded. These findings suggest that virginiamycin is superior to the probiotic as a growth promotant for swine. Also, housing pigs under crowded conditions does not increase the level of response to virginiamycin.
Composting for Mortality Disposal on Hog Farms
Harper, Allen F. (Virginia Cooperative Extension, 2009)
Even on well-managed hog farms, some animals die before being marketed. A practical, cost-effective, and environmentally sound means to dispose of routine death losses is essential on all hog farms.
Cytokine mRNA Expression in the Small Intestine of Weanling Pigs Fed Diets Supplemented with Specialized Protein or Peptide Sources
Zhao, J.; Harper, Allen F.; Webb, Kenneth E. Jr.; Kuehn, Larry Alexander; Gilbert, Elizabeth R.; Xiao, X.; Wong, Eric A. (2008-12)
Cytokines play a central role in the mucosal immune response and are involved in regulation of nutrient absorption, metabolism and animal growth This study investigated the effect of diet manipulation with specialized protein or peptide sources on expression of cytokine (IL-1, IL-6, IL-10, and TNF-alpha) mRNA abundance in different intestinal regions and at different ages post-weaning in piglets. A total of 48 (17 days of age, 6.16 +/- 0.34 kg BW) weanling pigs were fed either a corn-soy/whey protein basal diet, the basal diet supplemented with spray-dried plasma protein (SDPP), or the basal diet supplemented with Peptiva (R), a hydrolyzed marine plant protein. A fourth treatment group was fed the SDPP diet, but the feed intake level was limited (SDPP-LF). Pigs were killed at 3 and 10 d, and intestinal cytokine mRNA was measured by real-time PCR using the relative quantification method. The SDPP-LF group exhibited an increased TNF-alpha mRNA abundance compared with the ad libitum SDPP group (p<0.05). The TNF-alpha and IL-10 mRNA abundance increased from the proximal to distal part of the intestine, and the mRNA abundance was greater (p<0.01) in the distal intestine as compared with the proximal and middle intestine. The cytokines IL-1-beta, IL-10 and TNF-alpha mRNA abundance also increased from d3 to d10 postweaning (p<0.01). In summary, restricted feeding increased the TNF-alpha mRNA abundance in the small intestine, however neither SDPP nor peptide supplementation affected cytokine mRNA expression. Abundance of mRNA for most cytokines examined in this study increased with age post-weaning, suggesting that during 10 d after weaning the mucosal immune system is still under development.
Developmental Regulation of the Expression of Nutrient Transporter and BrushBorder Membrane Hydrolase Genes in the Small Intestine of Piglets
Xiao, Xunjun (Virginia Tech, 2005-12-14)
The objective of this study was to evaluate developmental regulation of the expression of nutrient transporter and brushborder hydrolase genes in the small intestine of piglets. Seventy piglets from seven sows were killed at birth (d 0), during suckling (d 1, 3, 7, 14, 21) and postweaning (d 22, 24, 28, 35), and intestinal segments (duodenum, jejunum and ileum) were collected. The mRNA abundance was determined by Northern blot using specific cDNA probes for three disaccharidases (lactase-phlorizin hydrolase, LPH, sucrase-isomaltase, SI, and maltase-glucoamylase, MGA), three peptide hydrolases (aminopeptidase A, APA, aminopeptidase N, APN, and dipeptidyl peptidase IV, DPP IV), two sugar transporters (Na+-dependent glucose transporter 1, SGLT1, and facilitated glucose transporter 5, GLUT5), a peptide transporter (H+-dependent peptide transporter 1, PepT1), four amino acid transporters (excitatory amino acid carrier 1, EAAC1, Na+-dependent neutral amino acid transporter, ATB0, the light chain of a heterodimeric transport system b0,+ involved in the heteroexchange of cationic and neutral amino acids, b0,+AT, and Na+-independent large branched and aromatic neutral amino acid transporter 2, LAT2), and two iron transporters (divalent metal ion transporter 1, DMT1, and iron-regulated transporter 1, IREG1). Protein expression was quantified by Western blot using specific antibodies for LPH, SI, SGLT1, and PepT1. During suckling, the abundance of LPH, APA, APN, DPP IV, b0,+AT mRNA increased quadratically (P < 0.001) with age from birth to d 7 or 14 then remained unchanged or slightly declined with age to d 21. The mRNA abundance of SI increased and LAT2 decreased linearly (P < 0.001) with age, and the abundance of MGA and GLUT5 mRNA remained unchanged with age. There was an age x intestinal segment interaction (P < 0.001) for the abundance of EAAC1 and ATB0 mRNA. The abundance of EAAC1 mRNA increased from d 0 through 14 and remained stable to d 21 in the ileum, and it was low and slightly increased with age through d 21 in the duodenum and jejunum. The abundance of ATB0 mRNA generally increased from d 0 to 21 in the duodenum and ileum, and increased from d 0 to 7 and then decreased to d 21 in the jejunum. The abundance of SGLT1 and PepT1 mRNA was substantial at birth and transiently declined to d 1. The abundance of SGLT1 mRNA generally increased from d 1 to 21, and PepT1 mRNA abundance increased to d 3 and then plateaued through d 21. Postweaning, the mRNA abundance of all of these carbohydrate and protein assimilation related genes increased during the first day (3 d for ATB0) after weaning then declined to the levels at weaning in the jejunum and ileum, followed by a subsequent change pattern that varied among genes. During suckling, the mRNA abundance of LPH, SGLT1, and APA was greater in the duodenum and jejunum than the ileum (P < 0.001). The PepT1 and APN mRNA was evenly distributed among intestinal segments, and the expression of MGA, DPP IV, EAAC1, b0,+AT, ATB0, and LAT2 mRNA was generally greater in the jejunum and ileum than the duodenum or greatest in the ileum. Postweaning, the mRNA abundance of all of these carbohydrate and protein assimilation related genes examined was generally greater in the jejunum and ileum than the duodenum or highest in the ileum. From d 0 through 35, DMT1 and IREG1 mRNA was predominantly (P < 0.05) distributed in the duodenum, where the abundance of DMT1 and IREG1 mRNA increased with age during suckling, and then rapidly decreased after weaning. The protein expression of LPH and SI exhibited a similar developmental pattern as that for the mRNA abundance. Unlike the developmental regulation of their respective mRNA abundance, the protein expression of SGLT1 exhibited a general decline from suckling to postweaning. The protein expression of PepT1 gradually decreased with age from birth to d 35 in the duodenum, and initially declined from birth to the lowest value then slightly increased with age through d 21, followed by an increase to d 35 in the jejunum and ileum. In conclusion, the gene expression of these brushborder hydrolases and nutrient transporters was not only differentially regulated by age but also differentially distributed along the small intestine of piglets at early stages of life. These differences in ontogenetic regulation and the distribution may be related to the luminal substrate concentration as well as the nutrient categories, and the developmental regulation of these genes may occur not only at the transcriptional level but also at the posttranscriptional level.
Effect of P.G. 600 on the timing of ovulation in gilts treated with Regu-mate
Horsley, Brandon Ryan (Virginia Tech, 2004-09-14)
We previously reported that ovulation rate, but not pregnancy rate or litter size at d 30 post-mating, was enhanced by gonadotropin treatment (P.G. 600; Intervet America Inc., Millsboro, DE) in gilts fed a progestin (Regu-mate; Intervet America Inc.) compared with gilts receiving progestin alone. We hypothesized that P.G. 600 altered the timing of ovulation, therefore mating gilts 12 and 24 h after first detection of estrus, as is common in the swine industry, may not have been the most appropriate breeding regimen. The objective of this study was to determine the effect of P.G. 600 on the timing of ovulation in gilts treated with Regu-mate. Randomly cycling, crossbred gilts (5.5 m of age, 117 kg BW, and 14.7 mm BF) were fed a diet containing Regu-mate to provide 15 mg/d for 18 d. Twenty-four h after Regu-mate withdrawal, gilts received i.m. P.G. 600 (n = 25) or saline (n = 25). Gilts were checked for estrus at 8 h intervals. After first detection of estrus, trans-rectal ultrasonography was performed at 8 h intervals to determine the time of ovulation. Gilts were killed 9 to 11 d after the onset of estrus to determine ovulation rate. All gilts displayed estrus by 7 d after treatment with P.G. 600 or saline. Compared with saline, P.G. 600 increased (P = 0.07) ovulation rate (14.8 + 1.1 vs. 17.5 + 1.0, respectively). The intervals from injection-to-estrus (98.4 + 2.7 vs. 110.9 + 2.7 h; P < 0.01) and injection-to-ovulation (128.6 + 2.8 vs. 141.9 + 3.2 h; P < 0.01) were decreased in gilts treated with P.G. 600 compared with gilts treated with saline. Estrus duration (54.4 + 2.3 vs. 53.7 + 2.5 h; P = 0.83), estrus-to-ovulation (30.2 + 2.0 vs. 31.7 + 2.2 h; P = 0.62) and time of ovulation as a percentage of duration of estrus (55.8 + 2.7 vs. 57.5 + 3.0%; P = 0.67) were similar for the P.G. 600 and saline-injected gilts, respectively. In summary, P.G. 600 advanced the onset of estrus and ovulation following termination of Regu-mate treatment and increased ovulation rate. However, treatment of gilts with P.G. 600 had no effect on the timing of ovulation relative to the onset of estrus.
Effect of vaccination against porcine circovirus type 2 (PCV2) on ejaculate characteristics and the shedding of virus in boar semen
Alberti, Kyle Anthony (Virginia Tech, 2010-05-05)
Research has demonstrated that porcine circovirus type 2 (PCV2) can be shed into boar semen, raising the possibility that artificial insemination may be an important route by which disease associated with PCV2 is transmitted. The objective of this experiment was to determine the effect of vaccination against PCV2 on ejaculate characteristics and PCV2-specific antibody titers in serum of PCV2-positive boars viremia and viral shedding in semen. Semen and blood samples were collected weekly from week 0 to week 8. After collections at week 0, boars were vaccinated with a commercial vaccine against PCV2 (n = 5) (Suvaxyn PCV2 One dose; Fort Dodge Animal Health, Fort Dodge, IA) or served as controls and received 2 ml 0.9% saline (n = 5). Sperm concentrations and characteristics of sperm motility were assessed using a computer-assisted sperm analysis system (Hamilton Thorne Research, Beverly, MA) and sperm morphology was evaluated after staining using light microscopy. The PCV2 antibody titers were determined in serum using an ELISA (Iowa State Veterinary Diagnostic Laboratory; Ames, IA). The genomic copy number of PCV2 DNA in serum and semen was determined by PCR (Iowa State Veterinary Diagnostic Laboratory; Ames, IA). There were no effects of treatment or treatment by week on semen characteristics (P > 0.05). An effect of treatment by week was detected for serum antibody titers (P < 0.01). Compared with controls, antibody titers in vaccinated boars tended to be greater at week 0 (1.13 ± 0.05 titer/ml vs 1.01 ± 0.05 titer/ml; P = 0.09) and were greater at week 2 (1.15 ± 0.05 titer/ml vs 1.01 ± 0.05 titer/ml; P < 0.05) but lesser at week 7 (1.01 ± 0.05 titer/ml vs 1.23 ± 0.05 titer/ml; P < 0.01) and tended to be lesser at week 8 (1.05 ± 0.05 titer/ml vs 1.17 ± 0.05 titer/ml; P = 0.07). There were no effects of treatment, week, or treatment by week for serum genomic copy number of PCV2 DNA (P > 0.1). An effect of week was detected for semen genomic copy number of PCV2 DNA (P < 0.04). During week 3, PCV2 genomic copy number was at its greatest numerical value, however, semen PCV2 genomic copy number was at its lowest point. This was followed by an increase in semen PCV2 genomic copy number during week 7. This increase could be related to the increase in viral shedding in the serum. In summary, vaccination against PCV2 can lower antibody titers when given post-infection and has no effect on indicators of semen fertility. Vaccination also can decrease the length of reoccurring infection by decreasing the length of viral shedding in serum.
Effects of a dietary antioxidant blend on growth performance, liver function, oxidative stress, and meat and fat quality in pigs and broiler chickens fed diets high in oxidants
Lu, Ting (Virginia Tech, 2013-08-22)
High feed ingredient prices have increased the use of by-products containing a high proportion of polyunsaturated fatty acids (PUFA) in pig and chicken feeds. This can increase the oxidation of other feed nutrients as well as causing oxidative stress in animals. Two studies were conducted to evaluate the effects of a dietary antioxidant blend (AOX, ethoxyquin and propyl gallate) in pigs and broiler chickens fed a diet high in oxidants. The objective of the first study was to evaluate the antioxidant blend on growth performance, meat quality, liver function, oxidative status, carcass characteristics, meat quality, and fatty acid profile in pigs. Crossbred barrows (n = 100, 10.91 ± 0.65 kg, 36 ± 2 d of age, Landrace × Duroc) were allotted to 5 treatments based on body weight (BW, 5 replicate pens per treatment, 4 pigs per pen). Treatments included: 1) HO: high oxidant diet containing 5% oxidized soy oil and 10% PUFA source (containing docosahexaenoic acid, DHA, 3.7% of diet); 2) VE: the HO diet with 11 IU/kg of added vitamin E; 3) AOX: the HO diet with AOX (135 mg/kg); 4) VE+AOX: the HO diet with both vitamin E and AOX; and 5) SC: a standard corn-soy control diet. The trial lasted for 118 d; on d 83, the HO diet pigs were switched to the SC diet because the animals were displaying very poor health. Compared with SC pigs, HO pigs had decreased average daily gain (ADG) and average daily feed intake (ADFI) from d 26 to 82 (P < 0.05). However, after switching the HO pigs to the SC diet, the VE treatment became the most stressed treatment with the poorest performance from d 83 to 118 (P < 0.05). The AOX restored pig performance to a level similar to pigs fed the SC diet (P > 0.05) with greater gain to feed ratio (G:F) for the entire period (P < 0.05). The AOX added treatments also attenuated the enlarged liver symptoms and reduced markers of liver stress including total bilirubin and aspartate transaminase, thiobarbituric acid reactive substances (TBARS) and carbonyl concentrations. In addition, the AOX addition in the high oxidant diet restored the lighter carcass weight, less back fat, less lean body mass and smaller loin eye area, decreased dressing percentage and intensive lipofuscin deposition induced by the high oxidant diet. However, the traits of loin muscle redness and belly firmness were not fully corrected by AOX. The second study was to investigate the antioxidant blend and vitamin E on growth performance, oxidative status, meat quality, fatty acid profile, liver function and inflammatory response in broiler chickens. Cobb 500 male broilers (n = 1200, 44.7 ± 0.8 g, d 0) were randomly distributed into 60 floor pens across 6 treatments with 10 replicate pens of 20 chicks each. Treatments included: 1) HO: high oxidant diet with vitamin E at 10 IU/kg, 3% oxidized oil, 3% PUFA source; 2) VE: the HO diet with vitamin E at 200 IU/kg; 3) AOX: the HO diet with AOX at 135 mg/kg, 4) VE+AOX: the HO diet with both vitamin E at 200 IU/kg and AOX at 135 mg/kg, 5) SC: standard control, a corn soy diet with vitamin E at 10 IU/kg, 3% non-oxidized soybean oil, no PUFA source, and 6) PC: positive control, the SC diet with AOX at 135 mg/kg. Compared to the SC birds, the PUFA added treatments (HO, VE, AOX, VE+AOX) groups had greater body weight, ADG and ADFI from d 0 through d 21 (P < 0.05). However, the growth of birds fed the VE treatment fell behind that of other treatments (P < 0.05) during the last 21 d of the trial. Compared to the HO birds, the AOX birds had lower TBARS and greater uric acid concentrations in the plasma, greater gene expression of superoxide dismutase and less drip loss, suggesting enhanced systematic antioxidant capability. In addition, dietary addition of AOX or AOX plus VE moderately improved liver function and reduced inflammation in fat tissue to a level similar to control groups. In both studies, the AOX supplement was effective in preserving PUFA, especially DHA deposition in the back fat of pigs and abdominal fat of chickens. These results suggest that feeding the high oxidant diet caused a series of changes in growth performance, liver function, oxidative status, carcass characteristics and meat quality in pigs, and AOX addition attenuated many of these. The supplementation of AOX also showed some effects on reducing oxidative stress in chickens. However, the effects were not as profound as the pig study.
The Effects of Genotype, Chromium Picolinate Supplementation, Sex, and Their Interactions on Growth Performance, Carcass Characteristics, and Muscle Quality in Pigs
Green, Brent Kenneth II (Virginia Tech, 1997-08-22)
Two trials (n = 160) were conducted to evaluate the effects of the halothane gene, chromium picolinate supplementation, and sex on growth performance, carcass characteristics, and meat quality in pigs. Halothane negative (NN) and halothane carrier (Nn) pigs (barrows, gilts) were supplemented with either 0 or 200 ppb chromium picolinate from 28.7 to 107.3 kg. There were no differences between genotypes for ADG or G/F. Chromium had no significant effect on any growth, carcass, or muscle quality characteristics, although chromium-fed pigs were slightly fatter. Barrows gained faster (P < .001) and consumed more feed (P < .001) than gilts, yielding heavier (P < .001) carcasses, and heavier (P < .05) wholesale cuts. Gilts had less backfat (P < .001) and larger (P < .01) LMA, and tended to gain more efficiently than barrows. Carrier pigs had lower pH values, higher CIE L* values, higher drip loss, and lower protein solubility (P < .05), all indicators of decreased quality. Chromium supplementation resulted in pork with higher (P<.05) CIE a*, CIE b*, and Chroma C values. Halothane carrier barrows and all gilts that were not fed chromium had lower lipid muscle content than NN barrows (P < .05). Gilts had higher CIE L* and a* values (P < .001), less lipid, and higher moisture percentage (P < .02) than barrows. Chromium picolinate did not negatively affect pork muscle quality.
Effects of Spray-Dried Porcine Plasma (SDPP) Administered as an Oral Gavage on Indicators of Health, Welfare, and Performance in Pigs Transported After Weaning
Wittish, Laura (Virginia Tech, 2011-06-30)
Transportation of swine is an emerging welfare issue, especially for piglets weaned and then immediately transported. Weaned pigs fed starter diets containing SDPP display improved growth performance. The objective of this study was to determine effects of pre-weaning SDPP on indicators of health, welfare, and performance in transported weaned pigs. Pigs were assigned to treatments: I. SDPP + transport, II. Water + transport, III. SDPP + no transport, or IV. Water + no transport. Pigs received their gavage twice daily for 5 d prior to weaning. Pigs were weaned and either transported or moved directly to the wean-to-finish barn. Rectal temperatures and blood samples were obtained at weaning and after relocation. Body weight was determined on d 1, at weaning, after relocation, and at weekly intervals for 5 wk thereafter. Blood chemistry profiles and serum cortisol concentrations were also determined. Rectal temperature and potassium increased and calcium decreased after groups I and II were transported. Glucose was lowest in group II. Total protein was greater in group I compared to group III. Albumin was greatest in group I compared to all other groups. Sodium was greatest in group II compared to all other groups. Anion gap was greatest in group II compared to group IV. Cortisol, phosphorus, gamma-glutamyltransferase, and chloride, were greater in groups I and II after transportation. In summary, transportation impacted several physiological indicators of health and well-being in weaned pigs, and providing SDPP prior to weaning prevented transportation-induced changes in sodium, glucose, and anion gap levels.
Efficacy and safety of a new genetically modified phytase for improving dietary phosphorus utilization of swine and poultry
Skaggs, James H. (Virginia Tech, 1999-08-19)
Four experiments were conducted to evaluate the efficacy and safety of a microbial phytase (Novo SP938) in weanling and grower pigs, and starter turkeys fed corn-soybean meal based diets. Pig and turkey BW and pen feed consumption were recorded weekly. Fecal and excreta samples were collected for determination of Ca and P digestibility. At the end of all experiments animals were slaughtered, and 10th ribs or right foot for pigs, and both middle toes for turkeys were removed for bone analysis. In pigs performance, bone measurements, and digestibilities of P and Ca increased as levels of phytase increased. Concentration of P and Ca in the feces decreased as dietary phytase increased. In turkeys, BW gain and toe ash increased as nonphytate P or phytase increased, when added to a low-P diet. Concentrations of P and Ca decreased as phytase was added to the diet. Based on nonlinear or linear equations, the average P equivalency of 500 U phytase/kg feed was .64 and .67 g of inorganic P for pigs and turkeys, respectively. There were no adverse effects of feeding 10,000 U phytase/kg feed in pigs and turkeys. Supplementation with Novo SP938 phytase was effective in improving performance, bone mineralization, P and Ca utilization, and decreasing P and Ca concentrations in the feces of pigs and excreta of young turkeys fed low-P diets, with no health effects, even at very high supplementation rates.
Enhancing Boar Reproductive Performance for Purposes of Artificial Insemination
Kozink, Daniel Michael (Virginia Tech, 2002-12-02)
The objectives were to: 1) determine if im treatments of Lutalyse expedited the training of sexually inexperienced boars for semen collection and increased spermatozoal output, and 2) determine the effects of dietary L-carnitine supplementation on boar libido, semen quality, sperm production, and maintenance of sperm motility during liquid storage. Experiment 1 utilized lean-type, terminal-line boars (National Pig Development, Roanoke Rapids, NC) (n = 40; 177.4 ± 2.4 d of age and 112.8 ± 2.0 kg body weight) that had not previously experienced natural mating. Boars were individually moved twice weekly for 6 weeks (total of 12 training sessions) to a semen collection room equipped with an artificial sow. Upon entering the semen collection room, boars received in treatments of either deionized water (4 mL, n = 10) or Lutalyse at doses of 5 mg (n = 10), 10 mg (n = 10), or 20 mg (n = 10), and subsequently received a libido score of 1 to 5 (1 = no interest in the artificial sow; 5 = mounting the artificial sow and allowing semen collection). The percentages of boars successfully trained for semen collection during the experimental period were similar (P > 0.05) for controls (20%) and boars receiving 5 mg (30%), 10 mg (20%), or 20 mg (10%) of Lutalyse. Average libido score for boars receiving 10 mg Lutalyse (2.35 ± 0.08) was greater (P < 0.05) than for controls (2.14 ± 0.06). Libido score for the 20 mg treatment group were (1.78 ± 0.06) lower (P < 0.05) compared to the other treatment groups. Characteristics of ejaculates (volume, gel weight, sperm concentration, total spermatozoa) from control boars and boars treated with Lutalyse at doses of 5, 10, or 20 mg were similar (P > 0.05). For Exp. 2, the same group of boars was utilized in two similar trials (Trial 1, 1a, 1b: n = 9 for control and L-carnitine-treated boars; Trial 2, 2a, 2b: n = 10 for control and L-carnitine-treated boars). Boars were fed a fortified, corn and soybean meal-based diet at a rate of 2 kg/d. Boars that were randomly selected for L-carnitine treatment received the same diet mixed with L-carnitine to achieve supplementation of 500 mg/d. For 16 wk, semen was collected weekly via the gloved hand method and was analyzed for gel-free volume, gel weight, sperm concentration, sperm per ejaculate, and characteristics of sperm motility. Time to ejaculation (reaction time), duration of ejaculation, and number of false mounts were also recorded for each collection. Trials 1a and 2a were conducted during weeks 16 and 17 for each respective trial. Boars were collected once on 4 consecutive days, allowed 4 d of rest, and then collected again, to estimate daily spermatozoal production. At the end of 16 wk, a semen sample was also processed and extended in Beltsville Thawing Solution (BTS) to achieve a dilution of 3 x 109 spermatozoa/100 mL-dose for Trials 1b and 2b. The extended semen was stored in plastic bottles at 18°C and motility was evaluated daily for 7 d post collection. L-carnitine supplementation for 16 wk had no effects on semen volume, gel weight, total number of sperm cells per ejaculate, reaction time, or sperm motility (P > 0.1). Boars receiving the L-carnitine-supplemented diet displayed an increase in the number of false mounts before ejaculating and an increase in sperm concentration (P < 0.05) in Trial 2. A treatment by week interaction was detected for sperm concentration in Trial 2 (P < 0.005). Increased sperm concentrations in L-carnitine-treated boars were demonstrated after only one week of feeding the respective diets. Given that the production of a mature sperm cell requires 7 to 8 wk in boars, it is therefore difficult to conclude that differences in sperm concentration were due solely to treatment. Daily spermatozoal production was similar between control boars and boars supplemented with L-carnitine (P > 0.1) for both Trials 1a and 2a. L-carnitine supplementation did not affect percent motility in Trials 1b and 2b or sperm progressive motility in Trial 2b during 7 d storage (P > 0.1). A treatment by day interaction was determined for sperm velocity (P < 0.05) in Trial 2b. L-carnitine supplementation decreased mean sperm velocity significantly after 2 d of storage. Overall, L-carnitine had no beneficial effects on boar libido, semen quality, sperm production, or maintenance of sperm motility during liquid storage. However, Lutalyse increased libido scores, but did not affect the number of boars trained for semen collection or number of spermatozoa ejaculated.
Growth Performance, Carcass Traits, and Reproductive Characteristics in Boars Fed Diets Supplemented With an Organic Source of Selenium
Speight, Susan Michelle (Virginia Tech, 2010-08-11)
The objectives of this study were to assess growth and reproductive performance of boars fed a diet supplemented with organic selenium (Se). Crossbred boars received one of three treatments: I. basal diet with no supplemental Se, II. basal diet supplemented with 0.3 ppm organic Se (Sel-Plex), and, III. basal diet supplemented with 0.3 ppm sodium selenite. Nursery (n = 13 pens/treatment) boar performance was not affected (P > 0.1) by diet and only grow-finish (n = 11 pens/treatment) G:F was greater (P < 0.06) for Sel-Plex (0.378) compared with selenite (0.368) or control (0.363) boars. At 15-mo of age semen was collected from boars (n = 10/treatment) over 5-d. Semen quality declined over time, but the negative impact day had on sperm motility was less pronounced with Sel-Plex boars. Effects of treatment x day were detected for progressively motile (P = 0.02) and rapidly moving (P = 0.03) spermatozoa, sperm path velocity (VAP; P = 0.05), and average velocity (VSL; P = 0.05). At 17-mo of age, semen was collected from boars (n = 10/treatment), extended and stored over 10-d. Although semen quality decreased over time, sperm from Sel-Plex boars resisted the negative effects of day on sperm motility and pH. Effects of treatment x day were detected for percent motile spermatozoa (P < 0.01), static spermatozoa (P < 0.01), VAP (P = 0.06), amplitude of head displacement (ALH; P = 0.02), straightness (P = 0.01), and pH (P < 0.01). At 23-mo of age, semen was collected (day 0) from boars (n = 6/treatment), extended, stored and evaluated at d 1 and 8 using in vitro fertilization. Dietary Se treatment failed to affect (P < 0.05) in vitro fertilizing rates of boars. In summary, dietary supplementation with Sel-Plex enhanced G:F in grow/finish boars. Dietary Sel-Plex supplementation may decrease the effects that stressors, such as intensive semen collection or semen storage, have on boar sperm characteristics such as sperm motility. The mechanisms for these responses remain to be elucidated.
Hog Production Contracts: The Grower-Integrator Relationship
Harper, Allen F. (Virginia Cooperative Extension, 2009)
Production contracts are a means of transferring business risk and defining production responsibilities within an integrated pork production system.
Impact of Dietary Proteins on Growth Performance, Intestinal Morphology, and mRNA Abundance in Weanling Pigs
Zhao, Junmei (Virginia Tech, 2005-09-15)
The objectives of these studies were to investigate the effects of two special proteins, spray-dried plasma protein (SDPP), a high quality protein source, and Peptiva®, a mixture of peptides manufactured from marine products, on growth performance, nitrogen balance and enzyme and nutrient transporter mRNA expression in the brushborder membrane in weanling pigs. The results indicated that 6 % SDPP increased ADG and ADFI in the first 10 d after weaning (P < 0.05) without carry-over benefits in subsequent phases. There were potential additive effects of SDPP and Cu on growth promotion. Trends for interaction of diet and pen sanitation were observed for G:F with more pronounced response to SDPP (P = 0.07) and Cu (P = 0.11) supplementation in the sub-sanitary pens. In the duodenum, reduced crypt depth with Cu supplementation (P < 0.01) and a trend for greater villous length with SDPP supplementation (P = 0.09) were observed. Pigs reared in the sub-sanitary pens had lower ADG (P < 0.05) as well as shorter villous length and less crypt depth (P < 0.05) than those from sanitary pens. To investigate the potential impact of dietary proteins on gene expression in the intestine, 54 weanling pigs were fed either 6 % SDPP, 0.5 % Peptiva®, or soy control diets, and were killed 3 or 10 d after weaning. Northern blot results revealed significant diet by intestinal segment interactions (P < 0.05) for aminopeptidase A and aminopeptidase N. Aminopeptidase A was evenly distributed along the small intestine in the Peptiva® group, but decreased dramatically in the ileum in other groups. Aminopeptidase N increased from the proximal to the distal intestine in the soy protein and SDPP groups, whereas in the Peptiva® group, relative abundance was highest in the jejunum and lowest in the duodenum. Most of the enzyme and nutrient transporter mRNA abundance was observed in the distal segements of the small intestine and changed as the animals matured. Due to the low abundance of cytokine mRNA expression in the intestine, mRNA levels of cytokine were quantified by Real-Time PCR. The results indicated that the pigs fed the SDPP diet tended to have lower pro-inflammatory cytokine IL-1-β and TNF-α compared to other treatments. Tumor necrosis factor--α and IL-10 mRNA abundance increased from the proximal to the distal intestine, and was higher (P < 0.05) in the ileum than in the duodenum and jejunum. The mRNA abundance of IL-1-β, IL-10, and TNF-α also increased as the animals matured (P < 0.01). In summary, SDPP increased growth performance of weanling pigs, which were associated with changes in intestinal morphology and function. Peptiva® influenced aminopeptidases distribution along the small intestine. The mRNA abundance for digestive enzymes, nutrient transporters, and cytokines were differentially regulated along the small intestine as pigs matured.
Impact of exogenous factors on amino acid digestibility in non-ruminants
Lee, Hanbae (Virginia Tech, 2012-04-30)
The nutritional value of an amino acid (AA) is determined by its bioavailability, however concept of digestibility is mostly used in practical situations. Four studies were conducted to test 2 exogenous factors that were hypothesized to affect the AA digestibility in non-ruminant animals. In study 1, broiler chicks were randomly allotted to 4 dietary treatments of control and distillers dried grains with solubles (DDGS, 20%) diets supplemented or not with a novel mixture of carbohydrases. Results indicated the ability of carbohydrase mixture to increase energy utilization of the DDGS diet, with significant improvements in AA digestibility, consequently improving growth performance of broilers. Study 2 examined effect of the carbohydrase mixture in pigs fed a high DDGS diet. Ileal cannulated growing pigs (n = 8, 64.3 ± 0.5 kg) were allotted to 4 dietary treatments in a replicated 4 Ã 4 Latin Square design. Control and DDGS (40%) diets were supplemented or not with a mixture of carbohydrases. Numeric increases for AA digestibility, along with a decreased tendency of urinary energy output suggested a possibility for improved nutrient utilization in pigs when carbohydrases were supplemented to 40% corn DDGS diet. Collectively, carbohydrase seems less effective for swine applications due to greater water content and consequently a lower viscosity in pig digesta. Next, study 3 showed changes in AA digestibility and endogenous AA losses (EAAL) when pigs were challenged orally with Salmonella enterica serovar Typhimurium. Nursery pigs (n = 48, 17.9 ± 0.5 kg) were randomly assigned to a 2 Ã 2 factorial arrangement consisting of two diets (control or N-free) and inoculation (sterile broth or 9.8 Ã 10^9 CFU of Salmonella). Measurements at 24 and 72 h post-inoculation indicated that AA digestibility of pigs is impaired through the initial phase of Salmonella infection and gradually restored, but not fully by 72 h. Finally, study 4 determined the dynamic fluctuations of EAAL and subsequent AA digestibility in response to Salmonella Typhimurium measured at multiple time points. Ileal cannulated pigs (n = 8, 76.0 ± 1.4 kg) were randomly assigned to either a control or a N-free diet and challenged orally with 1.3 Ã 10^10 CFU of Salmonella. Inflammatory diarrhea was associated with reduced AA digestibility and increased EAAL showing respective peak values at 8-16 h post-inoculation. Alterations in AA digestibility and EAAL were gradually recovered to near pre-inoculation values by 56-64 h post-inoculation, but showed impaired digestibility at 72-80 h post-inoculation.
Livestock Update. February 2010
Greiner, Scott P.; McCann, Mark A.; Wahlberg, Mark L.; Estienne, Mark J.; Harper, Allen F. (Virginia Cooperative Extension, 2010-02-02)
Includes articles on February beef management, upcoming beef convention and webinar, including clover in forage plans, crossbreeding cattle, buying bulls, bull test and bred heifer sale, ewe nutrition and management, newborn lamb management, and swine welfare
Livestock Update. January 2011
Greiner, Scott P.; McCann, Mark A.; Saville, Joi; Harper, Allen F. (Virginia Cooperative Extension, 2011-01-01)
Contains articles on January beef management, winter feeding tips for cattle, across breed EPDs, upcoming beef webinar, bull sale results, upcoming shepherds' symposium, a sheep update, and feral pigs
Methionine and glucose transport by isolated intestinal brush border membrane vesicles from pigs and lambs fed an Aspergillus product
Jang, Insurk (Virginia Tech, 1993-10-05)
This study was designed to determine whether feeding an Aspergillus product would influence growth or feed utilization and intestinal mucosal cell function as indicated by uptake of methionine and glucose by isolated intestinal brush border membrane vesicles (BBMV). In Experiment 1, 24 weanling pigs were paired by sex, BW, and litter and were allotted, within pairs, to either an 18% CP corn-soy diet (control) or the same diet supplemented (.15%) with an Aspergillus product. There were no differences (P > .05) in ADG, daily feed intake, or feed/gain between the two groups. In Experiment 2, 24 weanling wether lambs were paired by BW and were randomly assigned within pair to a 14% CP diet containing 61.1 % cracked corn, 17.3% soybean meal, and 15% ground orchard grass hay (control) or the same diet fortified (.07%) with an Aspergillus product. There were no differences (P > .05) in ADG, daily feed intake, or feed/gain between the two groups. Enrichment of alkaline phosphatase in BBMV used in transport studies were 12.7-fold higher in pigs and 5.6-fold higher in lambs over the original homogenate.
Phytase Impacts Various Non-Starch Polysaccharidase Activities on Distillers Dried Grains with Solubles
Wagner, Ashley Leigh (Virginia Tech, 2008-08-05)
As environmental concerns increase in the U.S., there is a push to go "green". This has fueled the development of ethanol production in the U.S. as a renewable source of energy. In the U.S., corn is used to produce ethanol. Therefore, displacement of corn used in the animal industry to ethanol production has, inevitably caused an increase in the price of corn. Replacing conventional ingredients, such as corn, in monogastric diets with lower cost by products can be attractive economically. The objective of this study was to determine if exogenous enzymes that free reducing sugars from fiber will increase the dispensability of bound nutrients in the economically favorable by-product of ethanol production, distillers dried grains with solubles (DDGS). Effects of non-starch polysaccharidase (NSPase) inclusion rates and combinations with phytase on the ability to release reducing sugars were investigated. Distillers dried grains with solubles was tested in vitro in combination with hemicellulase (0, 0.1, 1, and 10 U/g of DDGS), cellulase (0, 1.5, 15, and 150 U/g of DDGS), xylanase (0, 2.5, 25, and 250 U/g of DDGS), ï ¢ glucanase (0, 0.006, 0.06, and 0.6 U/g of DDGS), and phytase (0, 250, 500, and 1,000 FTU/kg of DDGS). Results indicated an inhibitory effect of phytase on the ability of NSPases to release reducing sugars from DDGS (P = 0.0004). A second study was conducted to determine individual enzyme kinetics of NSPase on pure substrates when combined with increasing concentrations of phytase. Cellulase (P = 0.03), xylanase (P = 0.09), and ï ¢-glucanase (P = 0.06) combined with increasing concentrations of phytase showed a reduction in the velocity of reducing sugars release from pure substrate. However, we speculate that due to the inability to reach Vmax, the Lineweaver-Burk results were inconclusive. The 1/Km was calculated for all enzymes, and the presence of phytase increased 1/Km for xylanase (P = 0.006). However, -1/Km did not change for cellulase (P = 0.62), ï ¢-glucanase (P = 0.20), and hemicellulase (P = 0.13). In addition, the 1/Vmax was calculated for all enzymes, and the presence of phytase decreased 1/Vmax for cellulase (P = 0.03) and ï ¢ glucanase (P = 0.01). However, the presence of phytase resulted in no change for the 1/Vmax for xylanase (P = 0.81) and hemicellulase (P = 0.14). The slopes of the regression lines for the Lineweaver-Burk plots showed no effect of the presence of phytase for cellulase (P = 0.40) and hemicellulase (P = 0.27). However, the presence of phytase decreased the linear slope for xylanase (P = 0.006), and increased the linear slope for ï ¢ glucanase (P = 0.006). In summary, phytase appears to act as an inhibitor of NSPase activity in the in vitro digestion on DDGS; however, inconsistent results from the inhibition curves preclude us from determining the type of inhibition.

Browsing by Author "Harper, Allen F."

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