Biomedical subjects

C V Maxwell

Publications and source records attributed to C V Maxwell.

At least 19 recordsLinked to original sources

PubMed2006

Effects of supplemental manganese on performance of growing-finishing pigs and pork quality during retail display.

Crossbred barrows and gilts (n = 168) were used to test the effects of supplemental Mn during the growing-finishing period on performance, pork carcass characteristics, and pork quality during 7 d of retail display. Pigs were blocked by BW and allotted within blocks to pens (5 pigs/pen in blocks 1, 2, 5, and 6, and 4 pigs/pen in blocks 3 and 4). A total of 36 pens was randomly assigned to 1 of 6 dietary treatments, where the basal diets were formulated with (PC) or without (NC) Mn in the mineral premix, and supplemented with 0 or 350 ppm (as-fed basis) of Mn from MnSO4 or a Mn-AA complex (AvMn). Pigs were slaughtered at a commercial pork packing plant when the lightest block of pigs averaged 113.6 kg. During fabrication, boneless pork loins were collected and transported to Oklahoma State University, where 2.5-cm-thick LM chops were packaged in a modified atmosphere (80% O2 and 20% CO2) and subsequently placed in display cases (2 to 4 degrees C) under continuous fluorescent lighting (1,600 lx) for 7 d. Pig performance was not (P > or = 0.44) affected by supplemental Mn; however, during the grower-II phase, pigs fed the basal diets including Mn consumed less (P < 0.02) feed and tended to be more efficient (P < 0.09) than pigs fed the basal diets devoid of Mn. Throughout the entire feeding trial, neither dietary nor supplemental Mn altered (P > or = 0.22) ADG, ADFI, or G:F. Chops from pigs fed the diets supplemented with MnSO4 received greater (P < or = 0.05) lean color scores and had a redder (greater a* and hue angle values), more vivid color than chops from pigs fed the diets supplemented with AvMn. Additionally, LM chops from pigs fed the PC diets supplemented with MnSO4 were darker (lower L* values; P < 0.05) than chops from pigs fed the NC diets or PC diets supplemented with 0 or 350 ppm of AvMn. Even though discoloration scores were similar during the first 4 d of display, chops from pigs fed the PC diets supplemented with MnSO4 were less (P < 0.05) discolored on d 6 and 7 of retail display than chops from pigs fed the PC or NC diets and diets supplemented with AvMn (dietary treatment x display time, P = 0.04). Results of this study indicate that feeding an additional 350 ppm of Mn from MnSO4 above the maintenance requirements of growing-finishing pigs does not beneficially affect live pig performance but may improve pork color and delay discoloration of pork during retail display.

Animal Feed↗

PubMed2006

Effect of supplemental iron on finishing swine performance, carcass characteristics, and pork quality during retail display.

Crossbred pigs (n = 185) were used to test the effects of dietary Fe supplementation on performance and carcass characteristics of growing-finishing swine. Pigs were blocked by BW, allotted to pens (5 to 6 pigs/pen), and pens (5 pens/block) were allotted randomly to either negative control (NC) corn-soybean meal grower and finisher diets devoid of Fe in the mineral premix, positive control (PC) corn-soybean meal grower and finisher diets with Fe included in the mineral premix, or the PC diets supplemented with 50, 100, or 150 ppm Fe from Availa-Fe (an Fe-AA complex). When the lightest block averaged 118.2 kg, the pigs were slaughtered, and bone-in pork loins were collected during fabrication for pork quality data. During the grower-I phase, there was a tendency for supplemental Fe to reduce ADG linearly (P = 0.10), whereas in the grower-II phase, supplemental Fe tended to increase ADG linearly (P = 0.10). Even though pigs fed NC had greater G:F during the finisher-I phase (P < 0.05) and across the entire trial (P = 0.07), live performance did not (P > or = 0.13) differ among dietary treatments. There were linear increases in 10th-rib fat depth (P = 0.08) and calculated fat-free lean yield (P = 0.06); otherwise, dietary Fe did not (P > 0.19) affect pork carcass muscling or fatness. Moreover, LM concentrations of total, heme, and nonheme Fe were similar (P > 0.23) among treatments. A randomly selected subset of loins from each treatment was further fabricated into 2.5-cm-thick LM chops, placed on styrofoam trays, overwrapped with polyvinyl chloride film, and placed in coffin-chest display cases (2.6 degrees C) under continuous fluorescent lighting (1,600 lx) for 7 d. During display, chops from NC-fed pigs and pigs fed the diets supplemented with 100 ppm Fe tended to have a more vivid (higher chroma value; P = 0.07), redder (higher a* value; P = 0.09) color than LM chops of pigs fed 50 ppm of supplemental Fe. Moreover, greater (P < 0.01) redness:yellowness ratios in chops from pigs supplemented with 100 ppm Fe indicated a more red color than chops from PC-fed pigs or pigs fed diets supplemented with 50 ppm Fe. In conclusion, however, increasing dietary Fe had no appreciable effects on performance, carcass, or LM characteristics, suggesting that current dietary Fe recommendations are sufficient for optimal growth performance, pork carcass composition, and pork quality.

Animal Feed↗

PubMed2006

The influence of different management systems and age on intestinal morphology, immune cell numbers and mucin production from goblet cells in post-weaning pigs.

At time of weaning, the immune system in piglets is not fully mature resulting in reduced growth and increased mortality. Early-weaned pigs transported to a segregated early weaning (SEW) facility have enhanced performance and gut development compared to conventional (CONV) pigs which may be due, in part, to decreased pathogen challenge. To gain further insight into SEW enhanced performance and gut development, gut samples from pigs weaned at 19+/-2 days were assessed during the post-weaning (PW) period. The numbers of cells expressing CD2, CD4, CD8, and CD172 (the 74-22-15 (SWC3) antibody is now known to be specific for CD172), MHC class II, and CD25 were quantified using immunohistochemistry. Additionally, samples of duodenum, jejunum, and ileum were evaluated for the production of neutral, acidic, and sulfuric mucins from goblet cells and morphological measurements were also made. No effects due to the management systems alone were observed for any of the parameters. However, there were interactive effects of age/time post-weaning and management system on the immune cells as well as on the mucin secreting goblet cells. There were no differences in gut morphology between SEW and CONV reared pigs.

Age Factors↗

PubMed2006

Ontogeny of T lymphocytes and intestinal morphological characteristics in neonatal pigs at different ages in the postnatal period.

To evaluate morphological characteristics and development of the immune system at different ages in neonatal pigs, 4 piglets were euthanized at 7, 14, and 18 d of age for collection of blood, bile, and intestinal tissue for morphological measurements. Blood was collected for differential cell counts, lymphocyte blastogenesis, immunoglobulin (Ig) concentrations, cytokine concentrations, and flow cytometric analysis. Bile was collected for quantification of Ig-A and Ig-M. Villus width and crypt depth from duodenum sections, as well as ileum crypt depth, were reduced (P < or = 0.08) in 18-d-old pigs compared with 7-d-old pigs. No age-related differences (P > or = 0.11) were observed in the number of goblet cells with neutral and acidic mucins, serum or enteric Ig concentrations, IL-2, IL-4, spontaneous lymphocyte proliferation, or leukocyte concentrations. When measured as counts per minute (cpm) and as a stimulation index (SI), lymphocyte proliferation responses to phytohaemagglutinin increased (P = 0.05) between 7 and 14 d of age; no changes (P = 0.10) occurred at 18 d of age. No age-related changes (P = 0.39) were observed in response to pokeweed mitogen (PWM) when measured as cpm; however, the SI from PWM-induced lymphocytes decreased (P = 0.04) 4-fold between 7 and 18 d of age. The CD4+:CD8+ and populations of lymphocytes expressing CD2+CD4+CD8- (T helper cells) and CD25+CD4+CD8- (activated T helper cells) were greater (P > or = 0.04) at 7 d of age than at 14 and 18 d. Populations of T lymphocytes, cytotoxic T cells (CD2+CD4-CD8+), activated lymphocytes (CD25+), and activated cytotoxic T cells (CD25+CD4-CD8+) were greater (P > or = 0.02) in 18-d-old pigs compared with 7-d-old pigs, whereas CD2+CD4-CD8- [double negative cells] were lower (P = 0.08) in 18-d-old pigs compared with 14-d-old pigs. The percentage of CD2+ T cells was 8.4% at 7 d of age, and by the time the pigs reached 18 d of age, the percentage of CD2+ T cells was 33.8%. Moreover, the percentage of gammadelta T cells was greater (P = 0.02) in 18-d-old pigs than in 7-d-old pigs (74.8 vs. 46.1%, respectively). Results indicate that the porcine immune system and gut are continuously changing as the young pig matures. Changes occurred in lymphocyte phenotypic expression and functional capabilities, as well as morphology and mucin production, and their role may be to further protect the neonate from antigenic challenge as protection from passive immunity declines.

Age Factors↗

PubMed2006

Effect of weaning age and commingling after the nursery phase of pigs in a wean-to-finish facility on growth, and humoral and behavioral indicators of well-being.

Pigs from one farrowing group in which gilts were bred to farrow pigs that would be either 14 or 21 d of age at weaning, were divided into older and younger age groups (108 pigs per group) and penned 12 pigs per pen in a wean-to-finish facility. At the end of the nursery phase, half the pigs in each age group were removed, rerandomized, and commingled for the finishing phase. The other half remained in their original pens. Pigs were fed common Phase 1 (d 0 to 14) and Phase 2 (d 14 to 35) nursery diets, and a common 4-phase program diet during growing/finishing, with transitions at 45, 68, and 90 kg of BW. The study ended when the lightest weight block averaged 107 kg. Blood was obtained on d 0, 2, 10, 27, 37, 44, and 65 after weaning to determine leukocyte concentrations. In addition, behavior was monitored during the nursery period at weaning (d 0), on d 7, 14, and 27 after weaning, and during the growing/finishing phase on d 35 (after commingling following the nursery phase), 38, 44, and 65 after weaning. Older pigs were heavier (P < 0.001) throughout the nursery period, and the BW difference between younger and older pigs increased from 2 to 6.5 kg at the start and end of the nursery period, respectively. Older pigs had a greater concentration of white blood cells (P < 0.05) and lymphocytes (P < 0.10) on d 0, 2, and 10 after weaning than younger pigs. Younger pigs spent less (P < 0.05) time resting on the day of weaning, and more (P < 0.05) time active during the overall nursery phase. During Phase 3 and in the overall finishing phase, younger pigs had greater (P < 0.01) ADG and G:F than older pigs. Moreover, during Phase 3, ADFI (as fed) decreased (P < 0.05) when older pigs were commingled compared with older pigs that were not commingled. There was no difference in ADFI of younger pigs, regardless of commingling (interaction; P < 0.10). Results of this study indicate that weaning age affects growth performance in a wean-to-finish facility, as well as behavioral and immunological responses to weaning and commingling after the nursery phase. Management strategies should be further explored to optimize these benefits without the detrimental effects on health observed during the nursery period in this study.

Age Factors↗

PubMed2005

Comparison of dietary selenium fed to grower-finisher pigs from various regions of the United States on resulting tissue Se and loin mineral concentrations.

A study was conducted to evaluate the mineral content of pork tissue with particular emphasis on Se between various states (regions) having different diet (grain) indigenous Se concentrations. The study involved 19 states in the north, central, and southern regions of the United States, with committee members of NCR-42 and S-1012 (formerly S-288). A total of 62 pigs were used, with collaborators sending 100-g samples each of loin, heart, and liver, and a 3- to 4-g sample of hair (collected along the topline) from two to five market-weight pigs to a common laboratory for analysis. Diets at each station were formulated with locally purchased soybean meal and grain that was either grown or normally fed to pigs within their state. Tissues were analyzed for Se, but only the loin was analyzed for the macro- and micromineral elements. Correlation of dietary minerals to the tissue element was determined. The results demonstrated differences in tissue Se among states (P < 0.01), with high correlations of dietary Se to loin (r = 0.84; P < 0.01), heart (r = 0.84; P < 0.01), liver (r = 0.83; P < 0.01), and hair Se (r = 0.90; P < 0.01) concentrations. The correlation of hair Se to the Se concentration of loin, heart, and liver tissues was high (r > 0.90; P < 0.01). States in the west-central region of the United States and west of the Mississippi river had higher dietary Se and tissue Se concentrations than states in the eastern section of the Corn Belt, east of the Mississippi river, and along the East Coast. Generally, states did not differ greatly in their loin macro- and micromineral concentrations. The simple correlation of dietary minerals to their corresponding loin mineral concentration was generally non-significant, but most macrominerals had decreasing mineral concentrations when the dietary mineral level was higher. These results indicate that regional differences in tissue Se were influenced more by the indigenous Se content of the diet (grain) fed to the pigs than from sodium selenite.

Animal Feed↗

PubMed2005

Effects of dietary magnesium and short-duration transportation on stress response, postmortem muscle metabolism, and meat quality of finishing swine.

Crossbred pigs, heterozygous for the halothane gene, were used to determine the effects of long-term dietary supplementation of magnesium mica (MM) and short-duration transportation stress on performance, stress response, postmortem metabolism, and pork quality. Pigs were blocked by weight, penned in groups (six pigs per pen), and pens (three pens per diet) were assigned randomly either to a control corn-soybean meal diet or the control diet supplemented with 2.5% MM (as-fed basis; supplemented at the expense of corn). Diets were fed during the early-finisher (0.95% lysine, as-fed basis; 43.7 to 68 kg) and late-finisher (0.85% lysine, as-fed basis; 68 to 103 kg) periods. At the conclusion of the 71-d feeding trial, 12 pigs from each dietary treatment were selected randomly and subjected either to no stress (NS) or 3 h of transportation stress (TS). Dietary MM had no effect (P > or = 0.40) on ADG or ADFI; however, G:F was improved (P < 0.05) during the early-finisher period when pigs were fed MM-supplemented diets. Plasma glucose concentrations were increased in TS pigs fed the control diet, but transportation did not affect plasma glucose in pigs fed 2.5% MM (diet x transportation stress; P = 0.02). Dietary MM did not affect blood lactate, cortisol, insulin, NEFA, Ca, or Mg concentrations in response to TS (diet x transportation stress; P > or = 0.13); however, circulating lactate, cortisol, and glucose concentrations increased in TS pigs (transportation stress x time; P < 0.01). The LM from TS pigs fed MM had higher initial (0-min) and 45-min pH values than the LM from NS pigs fed the control diet (diet x transportation stress x time; P = 0.07). Lactic acid concentration and glycolytic potential were greater in the LM of TS pigs fed MM than TS pigs fed control diets (diet x transportation stress; P < or = 0.01). Although some trends were identified, neither MM (P > or = 0.15) nor TS (P > or = 0.11) altered the color or water-holding capacity of the LM and semimembranosus. The transportation model elicited the expected changes in endocrine and blood metabolites, but dietary MM did not alter the stress response in pigs. Conversely, although pork quality traits were not improved by dietary MM, delaying postmortem glycolysis and elevating 0- and 45-min muscle pH by feeding finishing diets fortified with MM may benefit the pork industry by decreasing the incidence of PSE pork in pigs subjected to short-duration, routine stressors.

Aluminum Silicates↗

PubMed2004

Effect of supplemental manganese on performance and carcass characteristics of growing-finishing swine.

Three hundred sixteen crossbred pigs were used in two experiments to determine the effect of supplemental manganese source and dietary inclusion level during the growing-finishing period on performance and pork carcass characteristics. All pigs were blocked by weight, and treatments were assigned randomly to pens within blocks. In Exp. 1, a total of 20 pens (five pigs/pen) was randomly assigned to one of five dietary treatments consisting of control grower and finisher diets, or control diets supplemented with either 350 or 700 ppm (as-fed basis) Mn either from MnSO4 or a Mn AA complex (MnAA). In Exp. 2, a total of 36 pens (six pigs per pen) was assigned randomly to one of six dietary treatments formulated with 0, 20, 40, 80, 160, or 320 ppm (as-fed basis) Mn from MnAA. Pigs were slaughtered when the lightest block averaged 120.0 kg (Exp. 1) or at a mean BW of 106.8 kg (Exp. 2). Neither ADG nor ADFI was affected (P > 0.21) by Mn source or high inclusion level (Exp. 1); however, across the entire feeding trial, pigs consuming 320 ppm Mn from MnAA were more (P < 0.04) efficient than pigs fed diets formulated with 20 to 160 ppm Mn from MnAA (Exp. 2). Color scores did not differ (P > 0.79) at the low inclusion (20 to 320 ppm Mn) levels used in Exp. 2; however, in Exp. 1, the LM from pigs fed Mn tended to receive higher (P = 0.10) American color scores than that of pigs fed the control diet, and Japanese color scores were higher for the LM from pigs fed diets containing 350 ppm Mn from MnAA than 350 Mn from ppm MnSO4 or 700 ppm Mn from MnAA (source x inclusion level; P = 0.04; Exp. 2). Chops of pigs fed 350 ppm Mn from MnAA were darker than the LM of pigs fed 350 ppm Mn from MnSO4, and 700 ppm Mn from MnAA diets (source x inclusion level; P = 0.03; Exp. 1), but L* values were not (P = 0.76) affected by lower MnAA inclusion levels (Exp. 2). Even though the LM tended to became redder as dietary MnAA inclusion level increased from 20 to 320 ppm Mn (linear effect; P < 0.10), a* values were not (P = 0.71) altered by including 350 or 700 ppm Mn (Exp. 1). Chops of pigs fed MnAA had lower cooking losses (P = 0.01) and shear force values (P = 0.07) after 2 d of aging than did chops from pigs fed diets formulated with MnSO4. Results from these experiments indicate that feeding 320 to 350 ppm Mn from MnAA during the growing-finishing period may enhance pork quality without adversely affecting pig performance or carcass composition.

Animal Feed↗

PubMed2004

Effects of dietary lysine and energy density on performance and carcass characteristics of finishing pigs fed ractopamine.

Two hundred sixteen crossbred barrows and gilts (84.3 kg BW) were used to test the effects of dietary energy density and lysine:energy ratio (Lys:ME) on the performance, carcass characteristics, and pork quality of finishing pigs fed 10 ppm ractopamine. Pigs were blocked by BW and gender, allotted to 36 pens (six pigs per pen), and pens were assigned randomly within blocks to dietary treatments (as-fed basis) arranged in a 2 x 3 factorial design, with two levels of energy (3.30 or 3.48 Mcal/kg) and three Lys:ME (1.7, 2.4, or 3.1 g lysine/Mcal) levels. Pigs were fed experimental diets for 28 d, and weights and feed disappearance were recorded weekly to calculate ADG, ADFI, and G:F. Upon completion of the feeding trial, pigs were slaughtered and carcass data were collected before fabrication. During carcass fabrication, hams were analyzed for lean composition using a ham electrical conductivity (TOBEC) unit, and loins were collected, vacuum-packaged, and boxed for pork quality data collection. Energy density had no (P > 0.22) effect on ADG or ADFI across the entire 28-d feeding trial; however, pigs fed 3.48 Mcal of ME were more (P < 0.02) efficient than pigs fed 3.30 Mcal of ME. In addition, ADG and G:F increased linearly (P < 0.01) as Lys:ME increased from 1.7 to 3.1 g/Mcal. Carcasses of pigs fed 3.48 Mcal of ME were fatter at the last lumbar vertebrae (P < 0.08) and 10th rib (P < 0.04), resulting in a lower (P < 0.03) predicted fat-free lean yield (FFLY). Conversely, 10th-rib fat thickness decreased linearly (P = 0.02), and LM depth (P < 0.01) and area (P < 0.01) increased linearly, with increasing Lys:ME. Moreover, FFLY (P < 0.01) and actual ham lean yield (P < 0.01) increased as Lys:ME increased in the diet. Dietary energy density had no (P > 0.19) effect on pork quality, and Lys:ME did not (P > 0.20) affect muscle pH, drip loss, color, and firmness scores. Marbling scores, as well as LM lipid content, decreased linearly (P < 0.01) as Lys:ME increased from 1.7 to 3.1 g/Mcal. There was a linear (P < 0.01) increase in shear force of cooked LM chops as Lys:ME increased in the finishing diet. Results indicate that 3.30 Mcal of ME/kg (as-fed basis) is sufficient for optimal performance and carcass leanness in pigs fed ractopamine. The Lys:ME for optimal performance and carcass composition seems higher than that currently used in the swine industry; however, feeding very high Lys:ME (> 3.0 g/Mcal, as-fed basis) to ractopamine-fed pigs may result in decreased marbling and cooked pork tenderness.

Animal Feed↗

PubMed2004

Effect of phosphorylated mannans and pharmacological additions of zinc oxide on growth and immunocompetence of weanling pigs.

Three experiments were conducted to evaluate the efficacy of phosphorylated mannans (MAN) and pharmacological levels of ZnO on performance and immunity when added to nursery pig diets. Pigs (216 in each experiment), averaging 19 d of age and 6.2, 4.6, and 5.6 kg of BW in Exp. 1, 2, and 3, respectively, were blocked by BW in each experiment, and penned in groups of six. A lymphocyte blastogenesis assay was performed in each experiment to measure in vitro lymphocyte proliferation response. In Exp. 1, diets were arranged as a 2 x 2 factorial with two levels of Zn (200 and 2,500 ppm) and two levels of MAN (0 and 0.3% from d 0 to 10, and 0 and 0.2% from d 10 to 38). Zinc oxide increased (P < 0.05) ADG, ADFI, and G:F from d 0 to 10, and ADG and ADFI from d 10 to 24. In Exp. 2, diets were arranged as a 2 x 3 factorial with two levels of Zn (200 and 2,500 ppm) and three levels of MAN (0, 0.2, and 0.3%). Pigs fed 2,500 ppm Zn from d 0 to 10 had greater (P < 0.05) ADG, ADFI, and G:F than pigs fed 200 ppm Zn. From d 10 to 24, ADG was similar when pigs were fed 200 ppm Zn, regardless of MAN supplementation; however, ADG increased (P < 0.05) when 0.2% MAN was added to dietscontaining 2,500 ppm Zn (MAN x Zn interaction, P < 0.05). In Exp. 3, diets were arranged as a 2 x 3 factorial with two levels of MAN (0 and 0.3%) and three levels of Zn (200, 500, and 2,500 ppm). Zinc was maintained at 200 ppm from d 21 to 35, so only two dietary treatments (0 and 0.3% MAN) were fed during this period. Average daily gain was greater (P < 0.05) from d 7 to 21 when pigs were fed 2,500 ppm Zn compared with pigs fed 200 or 500 ppm Zn. The addition of MAN improved (P < 0.05) G:F from d 7 to 21 and d 0 to 35. Lymphocyte proliferation of unstimulated cells and phytohemagglutinin-stimulated cells was decreased (P < 0.05) in cells isolated from pigs fed MAN compared with cells isolated from pigs fed diets without MAN. Lymphocyte proliferation of pokeweed mitogen-stimulated cells isolated from pigs fed MAN was less (P < 0.05) than for pigs fed diets devoid of MAN when diets contained 200 ppm Zn; however, MAN had no effect on lymphocyte proliferation when the diet contained 500 or 2,500 ppm Zn (MAN x Zn interaction, P < 0.05). Although the magnitude of response to MAN was not equivalent to that of pharmacological concentrations of Zn, MAN mayimprove growth response when pharmacological Zn levels are restricted.

Animal Feed↗

PubMed2004

Dietary supplementation with phosphorylated mannans improves growth response and modulates immune function of weanling pigs.

Phosphorylated mannans derived from the yeast cell wall of Saccharomyces cerevisiae may beneficially modulate immune function in the weanling pig, possibly providing an alternative to the use of dietary growth-promoting antibiotics. Therefore, in this study, 32 pigs averaging 19 d of age and 5.7 +/- 0.2 kg initial BW were randomly assigned to 16 pens in an environmentally controlled nursery to determine the effects of dietary supplementation with phosphorylated mannans on growth and immune function. Average daily gain and G:F ratio increased (P < 0.05) when pigs were fed diets supplemented with mannans from d 0 to 14 after weaning and in the overall experiment. Percentage of neutrophils was lower (P < 0.08) and percentage of lymphocytes was higher (P < 0.05) in blood from pigs fed mannans than when pigs were fed the basal diet. Lamina propria macrophages isolated from pigs fed diets containing mannans phagocytosed a greater (P < 0.05) number of sheep red blood cells (2.63 +/- 0.11) than did lamina propria macrophages isolated from pigs fed the basal diet (2.31 +/- 0.11). On d 19 after weaning, pigs fed diets supplemented with mannans tended to have a greater (P < 0.10) percentage of CD14+ lamina propria leukocytes than did pigs fed the basal diet. On d 21 following weaning, the percentage of CD14+MHCII+ leukocytes isolated from lamina propria tissue tended (P < 0.10) to be lower when pigs were fed mannans than when pigs were fed the basal diet. Pigs fed diets containing mannans had a lower (P < 0.05) ratio of CD3+CD4+:CD3+CD8+ T lymphocytes isolated from jejunal lamina propria tissue only on d 21 after weaning compared with pigs fed the basal diet. Supplementation of mannans in the diets of weanling pigs improved gain and efficiency, and intermittently affected selected components of the young pigs' immune function both systemically and enterically.

Animal Feed↗

PubMed2004

Isoleucine requirements and ratios in starting (7 to 11 kg) pigs.

Two experiments were conducted to refine the Ile needs in 7- to 11-kg pigs. In Exp. 1, 1,680 pigs were fed a 1.25% digestible Lys diet containing 7.5% spray-dried blood cells (as-fed basis) with supplemental crystalline Ile (0.06% increments) to generate seven levels of apparent digestible Ile (0.47 to 0.83%). There were 12 replicates of each treatment with 20 pigs per pen, and treatments were imposed at an initial BW of 7 kg and continued for 16 d. Responses in ADG, ADFI, G:F, and plasma urea nitrogen (PUN) were quadratic (P < 0.01) over the 16-d period. Data were fitted to both a single-slope broken line and a quadratic fit, and when the quadratic response curve was superimposed on the broken line, the points at which the quadratic curve first intersected the plateau of the broken line occurred at 0.70, 0.73, 0.66, and 0.65% digestible Ile for ADG, ADFI, G:F, and PUN, respectively. Using the ADG and ADFI obtained at this intersection point resulted in an estimate of 9.1 mg of digestible Ile per gram of weight gain. In Exp. 2, 1,840 pigs were fed similarly composed diets, except that digestible Lys was lowered in six diets to 1.10% by decreasing soybean meal. Crystalline Ile was supplemented at 0.09% increments to generate six levels of digestible Ile (0.37 to 0.83%). A seventh diet contained 1.25% digestible Lys by supplementing the 0.83% digestible Ile diet with 0.19% L-Lys HCl to verify that 1.10% digestible Lys was deficient for these pigs. There were 12 replicates of each treatment with 22 pigs per pen, and treatments imposed at an initial BW of 7 kg and continued for 16 d. Supplementation of Lys to the 0.83% digestible Ile diet (1.10 vs. 1.25% digestible Lys) did not affect ADG (260 vs. 264 g/d, P = 0.60) and ADFI (359 vs. 343 g/d, P = 0.20), whereas G:F (725 vs. 774 g/kg, P < 0.01) was improved by increasing dietary Lys. Responses in ADG, ADFI, and G:F to the first six diets were quadratic (P < 0.01) over the 16-d period. The points at which the quadratic curve first intersected the plateau of the broken line occurred at 0.686, 0.638, and 0.684% digestible Ile for ADG, ADFI, and G:F, respectively. Using the ADG and ADFI obtained at this intersection point results in an estimate of 9.9 mg of digestible Ile per gram of weight gain. These results suggest that although the percent digestible Ile requirement and digestible Ile:Lys ratio for starter (7 to 11 kg) pigs may be higher than 1998 NRC recommendations, the requirement may be lower than current recommendations when taking gain and feed intake into account.

Animal Feed↗

PubMed2004

Utilization of spray-dried blood cells and crystalline isoleucine in nursery pig diets.

Three experiments were conducted to evaluate spray-dried blood cells (SDBC) and crystalline isoleucine in nursery pigs. In Exp. 1, 120 pigs were used to evaluate 0, 2, 4, and 6% SDBC (as-fed basis) in a sorghum-based diet. There were six replicates of each treatment and five pigs per pen, with treatments imposed at an initial BW of 9.3 kg and continued for 16 d. Increasing SDBC from 0 to 4% had no effect on ADG, ADFI, and G:F. Pigs fed the 6% SDBC diet had decreased ADG (P < 0.01) and G:F (P = 0.06) compared with pigs fed diets containing 0, 2, or 4% SDBC. In Exp. 2, 936 pigs were used to test diets containing 2.5 or 5% SDBC (as-fed basis) vs. two control diets. There were six replicates of each treatment at industry (20 pigs per pen) and university (six pigs per pen) locations. Treatments were imposed at an initial BW of 5.9 and 8.1 kg at the industry and the university locations, respectively, and continued for 16 d. Little effect on pig performance was noted by supplementing 2.5% SDBC, with or without crystalline Ile, in nursery diets. Pigs fed the 5% SDBC diet without crystalline Ile had decreased ADG (P < 0.01), ADFI (P < or = 0.10), and G:F (P < 0.05) compared with pigs fed the control diets. Supplementation of Ile restored ADG, ADFI, and G:F to levels that were not different from that of pigs fed the control diets. In Exp. 3, 1,050 pigs were used to test diets containing 5, 7.5, or 9% SDBC (as-fed basis) vs. a control diet. There were six replicates of each treatment at the industry (20 pigs per pen) location and five replicates at the university (six pigs per pen) locations. Treatments were imposed at an initial BW of 6.3 and 7.0 kg at the industry and university locations, respectively, and continued for 16 d. Supplementation of 5% SDBC without crystalline Ile decreased ADG and G:F (P < 0.01) compared with pigs fed the control diet, but addition of Ile increased ADG (P < 0.01) to a level not different from that of pigs fed the control diet. The decreased ADG, ADFI, and G:F noted in pigs fed the 7.5% SDBC diet was improved by addition of Ile (P < 0.01), such that ADG and ADFI did not differ from those of pigs fed the control diet. Pigs fed diets containing 9.5% SDBC exhibited decreased ADG, ADFI, and G:F (P < 0.01), all of which were improved by Ile addition (P < 0.01); however, ADG (P < 0.05) and G:F (P = 0.09) remained lower than for pigs fed the control diet. These data indicate that SDBC can be supplemented at relatively high levels to nursery diets, provided that Ile requirements are met.

Animal Feed↗

PubMed2003

Effect of feather meal on live animal performance and carcass quality and composition of growing-finishing swine.

A total of 252 crossbred pigs were used in two experiments to determine the effect of feeding hydrolyzed feather meal (FM) during the growing-finishing period on animal performance, carcass composition, and pork quality. All pigs were blocked by weight, and dietary treatments were assigned randomly to pens within blocks. In Exp. 1, 24 pens were randomly assigned to one of three dietary treatments: 1) control corn-soybean meal starter, grower, and finisher diets devoid of FM; 2) control diets formulated with 3% FM; and 3) control diets formulated with 6% FM. During the starter phase, there was a quadratic decrease in average daily gain (P < 0.06) and gain:feed (P < 0.01) with increasing FM, and during the grower-II phase, gain:feed increased linearly (P < 0.07) with increasing FM inclusion level. However, dietary FM had no effects (P > 0.10) on performance during the grower-I phase, finisher phase, or in the overall trial. Moreover, carcasses from pigs fed 3% FM had greater (P < 0.05) average backfat depth than carcasses of pigs fed 0 and 6% FM, but FM did not affect (P > 0.10) ham or carcass lean composition. In Exp. 2, 24 pens were randomly allotted to one of four dietary treatments: 1) positive control corn-soybean meal-based starter, grower, and finisher diets; 2) negative control corn-soybean meal- and wheat middlings-based starter, grower, and finisher diets; 3) negative control diets formulated with 3% FM; and 4) negative control diets formulated with 6% FM. Dietary FM had no effect (P > 0.10) on average daily gain, average daily feed intake, or gain:feed during any phase of the experiment. Ham weight decreased linearly (P < 0.04), whereas ham lean weight increased linearly (P < 0.09), with increasing levels of FM in the diet. Pork from pigs fed 3% FM tended (quadratic effect, P < 0.10) to receive higher Japanese color scores than pork from pigs fed either negative control or 6% FM diets. Moreover, pork color became lighter (P c 0.08), less red (P < 0.001), and less yellow (P < 0.003) as FM level was increased in swine diets. Results from these two experiments indicate that as much as 6% FM can be incorporated into isolysinic diets of growing-finishing pigs without adversely impacting animal performance, carcass composition, or pork quality.

Adipose Tissue↗

PubMed2003

Variability in mixing efficiency and laboratory analyses of a common diet mixed at 25 experiment stations.

An experiment involving 25 experiment stations in the North Central and Southern regions (NCR-42 and S-288, respectively) was conducted to assess the degree of uniformity of diet mixing among stations and to assess the variability among station laboratories in chemical analysis of mixed diets. A fortified corn-soybean meal diet was mixed at each station using a common diet formula (except for vitamin and trace-mineral additions). The diet was calculated to contain 14% crude protein (CP), 0.65% Ca, 0.50% P, and 125 ppm Zn (based on 100 ppm added Zn). After mixing, samples were collected from the initial 5% of feed discharged from the mixer, after 25, 50, and 75% was discharged, and from the final 5% of discharged feed. The five samples were sent to the University of Kentucky, finely ground, and divided into subsamples. Each set of five subsamples from each station was distributed to three randomly selected stations for analysis of CP, Ca, P, and Zn (i.e., each station analyzed five diet sub-samples from three other stations). In addition, two commercial and two station laboratories analyzed composites of the five subsamples from each of the 25 mixed diets. Based on the laboratories that analyzed all diets, means were 13.5, 0.65, and 0.52%, and 115 ppm for CP, Ca, P, and Zn, respectively. Ranges of 11.8 to 14.6% CP, 0.52 to 0.85% Ca, 0.47 to 0.58% P, and 71 to 182 ppm of Zn were found among the 25 diet mixes. The coefficients of variation among the 25 diet samples for CP, Ca, P, and Zn were 4.3, 9.3, 4.1, and 17.4%, and among the 25 laboratories were 3.6, 12.5, 10.7, and 11.1%, respectively. Overall analyses of the five sub samples were, respectively, CP: 13.4, 13.6, 13.4, 13.5, and 13.4% (P < 0.06); Ca: 0.66, 0.67, 0.67, 0.66, and 0.67%; P: 0.50,0.51,0.51,0.50, and 0.50%; and Zn: 115, 116, 112, 113, and 120 ppm (P < 0.001). Diets were not uniformly mixed at all stations (station x sample No. was P < 0.08 for Ca and P < 0.01 for CP, P, and Zn). Among stations, the range of the five samples, expressed as a percentage of the mean and averaged for CP, Ca, P, and Zn, varied from +/- 1.1% (i.e., 98.9 to 101.0%) to +/- 12.9% (84.6 to 110.4%), with an overall average of +/- 5.2%. Neither type nor volume of mixers was related to mixing uniformity. The results suggest that uniformity of diet mixes varies among experiment stations, that some stations miss their targeted levels of nutrients (especially Zn), and that the variability among experiment station laboratories in analysis of dietary Ca, P, and Zn in mixed diets is quite large.

Animal Feed↗

PubMed2002

Effect of dietary mannan oligosaccharides and(or) pharmacological additions of copper sulfate on growth performance and immunocompetence of weanling and growing/finishing pigs.

Two experiments were conducted to determine the efficacy of mannan oligosaccharides (MOS) fed at two levels of Cu on growth and feed efficiency of weanling and growing-finishing pigs, as well as the effect on the immunocompetence of weanling pigs. In Exp. 1, 216 barrows (6 kg of BW and 18 d of age) were penned in groups of six (9 pens/treatment). Dietary treatments were arranged as a 2 x 2 factorial consisting of two levels of Cu (basal level or 175 ppm supplemental Cu) with and without MOS (0.2%). Diets were fed from d 0 to 38 after weaning. Blood samples were obtained to determine lymphocyte proliferation in vitro. From d 0 to 10, ADG, ADFI, and gain:feed (G:F) increased when MOS was added to diets containing the basal level of Cu, but decreased when MOS was added to diets containing 175 ppm supplemental Cu (interaction, P < 0.01, P < 0.10, and P < 0.05, respectively). Pigs fed diets containing 175 ppm Cu from d 10 to 24 and d 24 to 38 had greater (P < 0.05) ADG and ADFI than those fed the basal level of Cu regardless of MOS addition. Pigs fed diets containing MOS from d 24 to 38 had greater ADG (P < 0.05) and G:F (P < 0.10) than those fed diets devoid of MOS. Lymphocyte proliferation was not altered by dietary treatment. In Exp. 2, 144 pigs were divided into six pigs/pen (six pens/treatment). Dietary treatments were fed throughout the starter (20 to 32 kg BW), grower (32 to 68 kg BW), and finisher (68 to 106 kg BW) phases. Diets consisted of two levels of Cu (basal level or basal diet + 175 ppm in starter and grower diets and 125 ppm in finisher diets) with and without MOS (0.2% in starter, 0.1% in grower, and 0.05% in finisher). Pigs fed supplemental Cu had greater (P < 0.05) ADG and G:F during the starter and grower phases compared to pigs fed the basal level of Cu. During the finisher phase, ADG increased when pigs were fed MOS in diets containing the basal level of Cu, but decreased when MOS was added to diets supplemented with 125 ppm Cu (interaction, P < 0.05). Results from this study indicate the response of weanling pigs fed MOS in phase 1 varied with level of dietary Cu. However, in phase 2 and phase 3, diets containing either MOS or 175 ppm Cu resulted in improved performance. Pharmacological Cu addition improved gain and efficiency during the starter and grower phases in growing-finishing pigs, while ADG response to the addition of MOS during the finisher phase seems to be dependent upon the level of Cu supplementation.

Animal Feed↗

PubMed2001

Alternative approaches to preterm labor.

Alternative approaches to the management of preterm labor have included home uterine activity monitoring, long-term tocolysis, bed rest, and intravenous hydration. Current evidence in the literature does not support improved pregnancy outcomes with these various therapies.

Bed Rest↗

PubMed2001

Relationship of twin zygosity and risk of preeclampsia.

OBJECTIVE: Twin gestations are known to be at higher risk for preeclampsia. One theory suggests that maternal recognition of fetal and trophoblastic tissues as foreign may be a factor. If that hypothesis is true, mothers carrying monozygous (MZ) gestations (ie a single fetal graft) might be predicted to have a lower rate of preeclampsia than those carrying dizygous (DZ) gestations. To evaluate this hypothesis, we compared the rate of preeclampsia in mothers with MZ and DZ twin gestations. STUDY DESIGN: Seven hundred sixty-eight twin deliveries from 1994 to 1999 were reviewed. Placental pathology reports were reviewed to determine the chorionic state of each placenta. Monochorionic placentas were assumed to be MZ. Dichorionic placentas were categorized as DZ if the neonates were of different sexes or different blood types. Maternal and fetal data were abstracted from the medical records. Preeclampsia was defined by standard criteria of the National Institutes of Health Working Group on High Blood Pressure. Our analysis was limited to women with pregnancies reaching at least 30 weeks of gestation where zygosity could be determined. RESULTS: Our analysis included 464 twin pregnancies, 154 MZ and 310 DZ. Among nulliparous women, the rate of preeclampsia was 15% (25/170) for DZ twins versus 20% (15/75) for MZ twins (P =.3). Among multiparous women, the rate was 8% (11/140) for DZ twins and 5% (4/79) for MZ twins (P =.4). In a logistic regression performed to control for confounding by maternal age, gestational age at delivery, assisted reproduction, and male sex, dizygotic state was associated with an odds ratio of 1.4 (95% CI = 0.5-3.9) for developing preeclampsia in nulliparous women and 1.2 in multiparous women (95% CI = 0.3-5.0). CONCLUSIONS: : These results do not support the hypothesis that zygosity affects the rate of preeclampsia in twin gestations, though the number of subjects in our study was too small to allow definitive conclusions. Larger studies are needed to evaluate this finding.

Adult↗