Glucose concentration in blood during exertion. 5. Use of the total distribution of blood glucose values during physical exercise or the estimation of response to exertion in various breeds of swine]

Blood glucose was determined by an enzymic method in 56 pigs of the German Edelschwein, German Landrace, German Saddleback breeds and Edelschwein/Landrace crosses before, during and after exercise on a belt moving at 1.3 metres/second for ten minutes, at 10 degrees C (winter) or 22-34 degrees C (summer) and relative humidity of 65-75%. Total plasma glucose was calculated from the plasma volume. Total scatter of values for blood glucose concentration and total plasma glucose was greater in Edelschwein and Saddlebacks than in Landrace and the crossbred pigs. There was a close and significant relationship between individual regulatory capacity and breed. The total scatter of blood glucose values was greater in winter than in summer.     

Evaluation of blood glucose concentration during exertion. 6. Effect of anemia on the glucose regulation capacity of domestic swine in standardized running exercise]

Individual mean blood glucose values and the scatter of individual values were determined in six healthy and six anaemic pigs before, during and after ten minutes of exercise on a belt moving at 78 m/min (environmental temperature 22-24 degrees C, relative humidity 55-65%). The glucose regulatory capacity of anaemic pigs was inferior to that of healthy pigs. Blood glucose regulation was related to haemoglobin content and to the increase in rectal temperature during exercise.     

Reactions of the domestic pig to exhausting motor stress of middle intensity

The VO 2max value was established from twelve pigs, followed by checks of their responses to endurance stress (walk 0.7 m/sec, ambient temperatures between 22 degress C and 24 degrees C, relative humidities between 67 and 78 per cent). Also measured were the rectal temperature, heart rate, respiratory rate, haemoglobin level of the blood, haematocrit, mean corpuscular haemoglobin concentration, plasma volume, blood volume, total haemoglobin, plasma glucose concentration and plasma lactid acid concentration. A differentiation could be made between one group weighing between 53.3 +/- 2.47 kg and enduring 97 +/- 9 minutes and another weighing 60.0 +/- 1.38 kg and enduring 36 +/- 6 minutes. The two groups differed from one another for their plasma and blood volumes, their values being 42.6 +/- 3.8 ml/kg and 67.5 +/- 7.5 ml/kg or 33.5 +/- 3.4 ml/kg and 52.2 +/- 5.9 ml/kg. The groups produced quantitatively different responses to endurance stress. The demands implied in endurance were widely met by the circulatory system, while the energy transfer was characterised primarily by aerobic energy collection.     

Effect of anemia on various reactions of the domestic swine due to physical exertion. 2. Components of cardiovascular function and body temperature]

The following measurements were made in six anaemic and six healthy pigs during and after physical exertion on a belt moving at 70 m/min for 10 minutes at environmental temperature of 22-24 degrees C and relative humidity of 55-65%:--rectal temperature (RT), heart rate, total haemoglobin, plasma volume (PV), blood volume (BV) and plasma osmolarity (PO). The increase: in RT and PO, heart rate during exercise, respiratory rate after exercise, and the fall in PV and BV during exercise as well as changes in erythrocytes were all more pronounced in anaemic pigs than in healthy pigs.     

Effect of anemia on various reactions of the domestic swine due to physical exertion. I. Initial values and characteristics of anemia]

In six anaemic and six healthy pigs at rest the following values were determined:--rectal temperature, heart rate, respiratory rate, haemoglobin (Hb), haematocrit (Hk), total haemoglobin (THb), plasma volume, blood volume, plasma osmolarity, lactic acid and glucose content of plasma, blood pH, carbon dioxide tension and base excess. There were significant differences between anaemic and normal pigs in Hb, THb, relative THb, Hk, mean cell haemoglobin concentration, lactic acid content; in the ECG there were differences in QT and ST intervals and the ratio of diastole to systole.     

Dietary tryptophan effects on plasma and salivary cortisol and meat quality in pigs

Four experiments were conducted to determine the effects of supplemental Trp on meat quality, plasma and salivary cortisol, and plasma lactate. Experiment 1 was a preliminary study to measure plasma cortisol concentrations in 4 barrows (50 kg of BW) that were snared for 30 s at time 0 min. Pigs were bled at -60, -30, -15, 2, 4, 6, 8, 10, 15, 20, 25, 30, 45, 60, 90, and 120 min. Plasma cortisol was near maximum 10 min after the pigs were snared. In Exp. 2, 20 barrows (50 kg of BW) were allotted to a basal corn-soybean meal diet or the basal diet with 0.5% supplemental l-Trp for 5 d. After the 5-d feeding period, pigs were snared for 30 s and bled at -10, 0, 2, 4, 6, 8, 10, 15, 20, 25, 30, 45, 60, 90, and 120 min after snaring. Pigs fed the diet with supplemental Trp had a lower (P < 0.01) mean plasma cortisol than pigs fed the basal diet. Plasma lactate also was decreased (P < 0.07) by supplemental Trp. In Exp. 3, the same pigs and treatments were used as in Exp. 2, but 5 pigs were snared and 15 pigs adjacent to those being snared were bled to determine if pigs are stressed when they are adjacent to pigs being snared. For pigs adjacent to snared pigs, the area under the curve (P < 0.06) and mean for plasma cortisol was lower (P < 0.01) in pigs fed Trp relative to those fed the basal diet. In Exp. 4, 90 barrows (initial BW of 106 kg) were allotted to 6 treatments in a 3 x 2 factorial arrangement. Three diets with Trp (basal diet, basal supplemented with 0.5% Trp for 5 d, or pigs fed the basal diet with a 0.1 g/kg of BW Trp bolus given 2 h before slaughter) were combined with 2 handling methods (minimal and normal handling). Dressing percent, 24-h pH, and 24-h temperature were reduced in the minimally handled pigs (P < 0.10) compared with the normally handled pigs. Pigs fed Trp in the diet relative to those fed the basal diet had increased 45-min temperature, Commission Internationale de l'Eclairage (CIE) redness (a*) and yellowness (b*) values, and drip and total losses (P < 0.10). Tryptophan in bolus form decreased 45-min pH in the minimally handled pigs but increased 45-min pH in the normally handled pigs (handling x Trp bolus interaction, P = 0.08). Tryptophan in the diet increased CIE lightness (L*) in minimally handled pigs but decreased CIE L* in the normally handled pigs (handling x Trp diet interaction, P = 06). No other response variables were affected by handling method or Trp. Results indicate that Trp decreases plasma cortisol but has no positive effect on meat quality.     

Effects of porcine growth hormone on glucose metabolism of pigs: I. Acute and chronic effects on plasma glucose and insulin status

The acute and chronic effects of porcine growth hormone (pGH) administration on glucose homeostasis of pigs were investigated in the present study. Twelve Yorkshire barrows (average BW = 65 kg) fitted with femoral artery catheters were allotted to three groups. Pigs received acute, intra-arterial injections of either pituitary pGH, a recombinantly derived pGH analog (ppGH or rpGH, 100 micrograms/kg BW) or saline. Acute injection of pGH did not affect fasting plasma glucose or insulin status. Pigs then were treated daily by i.m. injection for 24 d with 70 micrograms ppGH/kg BW. Serum glucose and insulin concentrations during the fed and fasted states were higher in pGH-treated than in control pigs. On d 25, an acute intra-arterial injection of ppGH (100 micrograms/kg BW) elicited increases in plasma glucose and insulin in pigs chronically treated with pGH. The area circumscribed by the glucose and insulin response curves 5 min to 7 h postinjection was 40% (P less than .005) and 177% (P less than .001), respectively, higher in ppGH-treated than in control pigs. These data indicate that pGH does increase plasma glucose and insulin in the fed and fasted states; however, this response is only observed after chronic pGH administration. In addition, pGH is capable of increasing plasma glucose and insulin acutely in the pig. This effect, however, only is observed in pigs treated chronically with pGH. The mechanisms by which pGH elicit these effects on glucose homeostasis are not known.     

Antagonistic effects of yohimbine in pigs anaesthetised with tiletamine/zolazepam and xylazine

Twelve healthy two-month-old Landrace x Yorkshire pigs of both sexes were randomly assigned to receive either tiletamine and xylazine (zx) or zolazepam and xylazine followed 20 minutes later by yohimbine (zxy). The pigs' scores for immobilisation and analgesia, and their rectal temperature, heart rate, respiration rate, pO(2), pCO(2), alkaline phosphatase, aspartate aminotransferase, glucose and total plasma proteins were determined before and five, 25, 45, 65 and 85 minutes after the administration of the tiletamine/zolazepam and xylazine. The mean total scores for immobilisation and analgesia of the zxy pigs were significantly lower than those of the zx pigs after 85 minutes. The mean rectal temperatures of the zxy pigs were significantly lower than those of zx pigs after 25, 45 and 65 minutes. The mean respiratory rates of the zx pigs were significantly lower than those of zxy pigs after five minutes. The mean pCO(2) of the zxy pigs were significantly lower than those of zx pigs five minutes after the administration of yohimbine. The mean glucose concentration of the zxy pigs were significantly lower than those of zx pigs after 65 and 85 minutes. The mean concentration total protein of the zxy pigs were significantly lower than those of zx pigs throughout the period of anaesthesia. Both groups became laterally recumbent within three minutes. When recovering from anaesthesia, the pigs treated with yohimbine took significantly less time to achieve sternal recumbency (mean [sd] 52.2 [8.9] v 76.2 [20.6] minutes) and less time to be able to stand (mean [sd] 77.0 [9.8] v 98.7 [15.8] minutes), and walk (mean [sd] 81.3 [11.3] v 110.8 [18.6] minutes).     

Lactic acid content of blood plasma in domestic swine of various breeds during physical exertion]

Lactic acid was determined by an enzymic method in plasma samples taken from 20 pigs of the German Edelschwein, German Landrace, German Saddleback and Edelschwein/Landrace crosses before, during and after being made to run on a band moving at 1.3 metres/second for ten minutes, at 10 degrees C and relative humidity of 65-75%. A special method was used to assess the degree of exertion. The lactic acid curve showed that Edelschwein and German Saddlebacks had a low regulatory capacity while German Landrace and the crossbred pigs had a large capacity. For assessing differences attributable to individuals or to breeds, the occurrence of the maximum lactic acid concentration during or after exercise was of special significance.     

Pharmacokinetics of fenbendazole following intravenous and oral administration to pigs

OBJECTIVE: To determine pharmacokinetics and metabolic patterns of fenbendazole after IV and oral administration to pigs. ANIMALS: 4 mixed-breed female pigs weighing 32 to 45 kg. PROCEDURE: Fenbendazole was administered IV at a dose of 1 mg/kg. One week later, it was administered orally at a dose of 5 mg/kg. Blood samples were collected for up to 72 hours after administration, and plasma concentrations of fenbendazole, oxfendazole, and fenbendazole sulfone were determined by use of high-pressure liquid chromatography. Plasma pharmacokinetics were determined by use of noncompartmental methods. RESULTS: Body clearance of fenbendazole after IV administration was 1.36 L/h/kg, volume of distribution at steady state was 3.35 L/kg, and mean residence time was 2.63 hours. After oral administration, peak plasma concentration of fenbendazole was 0.07 microg/ml, time to peak plasma concentration was 3.75 hours, and mean residence time was 15.15 hours. Bioavailability of fenbendazole was 27.1%. Oxfendazole was the major plasma metabolite, accounting for two-thirds of the total area under the plasma concentration versus time curve after IV and oral administration. Fenbendazole accounted for 8.4% of the total AUC after IV administration and 4.5% after oral administration. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that fenbendazole was rapidly eliminated from plasma of pigs. The drug was rapidly absorbed after oral administration, but systemic bioavailability was low.     

Effects of dietary supplementation with L-carnitine and fat on blood acid-base responses to handling in slaughter weight pigs

Blood acid-base responses to handling were evaluated in slaughter weight pigs fed diets supplemented with l-carnitine and fat. The study was carried out as a randomized block design with a 2 x 2 factorial arrangement of treatments: 1) dietary L-carnitine supplementation (0 vs. 150 ppm, as-fed basis); and 2) dietary fat supplementation (0 vs. 5%, as-fed basis). Sixty pigs (91.1 +/- 5.14 kg BW) were housed in mixed-gender groups of five and had ad libitum access to test diets (0.68% true ileal digestible lysine, 3,340 kcal of ME/kg, as-fed basis) for 3 wk. At the end of the feeding period (110.3 +/- 7.52 kg BW), pigs were subjected to a standard handling procedure, which consisted of moving individual animals through a facility (12.2 m long x 0.91 m wide) for eight laps (up and down the facility), using electric prods (two times per lap). There was no interaction between dietary L-carnitine and fat supplementation for any measurement. Pigs fed 150 ppm of supplemental L-carnitine had lower baseline blood glucose (P < 0.05) and higher baseline blood lactate (P < 0.05) concentrations than the nonsupplemented pigs. After handling, pigs fed L-carnitine-supplemented diets had a higher (P < 0.05) blood pH and showed a smaller (P < 0.05) decrease in blood pH and base excess than those fed the nonsupplemental diets. Baseline plasma FFA concentrations were higher (P < 0.01) in pigs fed the 5% fat diet. After the handling procedure, blood glucose, lactate, and plasma FFA were higher (P < 0.05) in pigs fed the 5 vs. 0% fat diets, but blood pH, bicarbonate, and base excess were not affected by dietary fat. The handling procedure decreased (P < 0.01) blood pH, bicarbonate, base excess, and total carbon dioxide and increased (P < 0.01) blood lactate, partial pressure of oxygen, and glucose, and also increased (P < 0.01) rectal temperature. Free fatty acid concentrations were increased by handling in pigs fed both 0 and 5% fat and 150 ppm L-carnitine. In conclusion, dietary L-carnitine supplementation at the level and for the feeding period evaluated in the current study had a relatively small but positive effect on decreasing blood pH changes in finishing pigs submitted to handling stress; however, dietary fat supplementation had little effect on blood acid-base balance.     

Intravascular macrophages in lungs of pigs infected with Haemophilus pleuropneumoniae

Pigs were inoculated intratracheally with a virulent or an avirulent isolate of Haemophilus pleuropneumoniae serotype 5 and sacrificed during the first 24 hours post-inoculation. Intravascular macrophages were examined by electron microscopic and morphometric techniques. Samples of lung were taken from regions with no macroscopic lesions (Zone 0), 2.5 to 3.0 cm from lesions (Zone 1), and from the immediate edge of lesions (Zone 2). Those pigs inoculated with the avirulent isolate did not develop lesions. Pigs given the virulent isolate consistently developed necrohemorrhagic lesions in the dorsolateral aspect of the caudal and middle lung lobes. Relative volumes of intravascular macrophages in Zones 1 and 2 increased with increased time post-inoculation; in pigs given the avirulent isolate, intravascular macrophage volume decreased with increased time post-inoculation. Cytoplasmic volume to nuclear volume ratios for macrophages in Zone 2 from pigs with necrohemorrhagic lesions progressively increased with increased time post-inoculation. Enlarged intravascular macrophages had large nuclei, prominent nucleoli, and abundant cytoplasm. Increased cytoplasmic volume was the result of increased numbers of lysosomes, phagosomes, rough and smooth endoplasmic reticulum, and large Golgi complexes. Pigs inoculated with the virulent bacteria had IV macrophages with large phagosomes that contained necrotic cell debris and fibrin. Macrophages with phagosomes were more frequent in the 6-, 9-, and 24-hour sample periods of pigs with lesions than in any other group. Intercellular adhesion plaques (ICAP) were present between IV macrophages and subjacent endothelial cells. ICAP's increased in length with increased time post-inoculation in Zones 1 and 2 from pigs with necrohemorrhagic lesions. In later sample periods, multiple closely associated and interlacing IV macrophages formed a discontinuous layer over endothelial cells in Zone 2 samples near necrohemorrhagic lesions. These results suggest that the intravascular macrophage population changes from immature macrophages to mature macrophages or immature epithelioid cells within 24 hours after inhalation of a virulent Haemophilus pleuropneumoniae. Furthermore, intravascular macrophages likely function to clear cellular and acellular debris from the blood in pneumonic conditions.     

Effect of chromium picolinate and chromium propionate on glucose and insulin kinetics of growing barrows and on growth and carcass traits of growing-finishing barrows

Two experiments were conducted to determine the effects of dietary Cr tripicolinate (CrPic) or Cr propionate (CrProp) on growth, carcass traits, plasma metabolites, glucose tolerance, and insulin sensitivity in pigs. In Exp. 1, 36 barrows (12 per treatment; initial and final BW were 20 and 38 kg) were allotted to the following treatments: 1) corn-soybean meal basal diet (control), 2) as 1 + 200 ppb Cr as CrPic, or 3) as 1 + 200 ppb Cr as CrProp. Growth performance data were collected for 28 d, and then 23 pigs (seven, eight, and eight pigs for treatments 1, 2, and 3, respectively) were fitted with jugular catheters and a glucose tolerance test (500 mg glucose/kg BW) and an insulin challenge test (0.1 IU of porcine insulin/kg BW) were conducted. Both CrPic and CrProp decreased (P < 0.05) ADG and ADFI but did not affect gain:feed (P > 0.10). Fasting plasma glucose, total cholesterol, urea N, insulin, and high-density lipoprotein cholesterol:total cholesterol concentrations were not affected (P > 0.10) by either Cr source. Pigs fed CrPic had lower (P < 0.02) fasting plasma NEFA concentrations than control pigs, but plasma NEFA concentrations of pigs fed CrProp were not affected (P > 0.10). During the glucose tolerance test, glucose and insulin kinetics were not affected by treatment (P > 0.10). During the insulin challenge test, glucose clearance was increased (P < 0.01) in pigs fed CrProp but not affected (P > 0.10) in pigs fed CrPic. Glucose half-life was decreased (P < 0.03) in pigs fed CrPic or CrProp, but insulin kinetics were not affected (P > 0.10). In Exp. 2, 48 barrows (four replicates of four pigs per replicate; initial and final BW were 23 and 115 kg) were allotted to the same dietary treatments in a growing-finishing study. Average daily gain, ADFI, and gain:feed were not affected (P > 0.10) by treatments. Carcass length tended (P = 0.10) to be greater in pigs fed CrPic than in pigs fed CrProp, but other carcass measurements were not affected (P > 0.10). Glucose kinetics from the insulin challenge test indicate that both CrPic and CrProp increase insulin sensitivity and that both Cr sources are bioavailable.     

Effect of floor area restriction upon performance, behavior and physiology of growing-finishing pigs

Fifteen groups of eight pigs were allocated .34, .68 or 1.01 m2 lying area per pig between 25 and 100 kg live weight. These values were chosen in accordance with Petherick's model to prevent all pigs from lying in full recumbency (.68 m2/pig) or on their sternum and belly (.34 m2/pig). Productivity decreased in the groups of pigs allowed only .34 m2/individual from 20 wk following the beginning of the experiment (70 to 80 kg). Behavioral changes were observed as early as 8 wk after the beginning of the experiment (60 to 70 kg). Severe area restriction increased time spent at the feeder. Aggression did not vary as a linear function of area allocation. Analysis of the main behavioral activities over a 10-h observation period revealed higher feeding time and lower social activity in pigs kept at .34 m2/pig. Sternum resting was more frequent than resting on the side when body weight reached 60 to 70 kg. Pigs that were submitted to the lower area allocation displayed enhanced resistance of their pituitary-adrenal axis to the dexamethasone suppression test and enhanced reactivity to adrenocorticotropic hormone injection. These findings demonstrate that behavioral and physiological responses are earlier and more sensitive indicators of adaptation to the environment than productivity.     

Effects of porcine growth hormone on glucose metabolism of pigs: II. Glucose tolerance, peripheral tissue insulin sensitivity and glucose kinetics

This study was conducted to determine whether the increase in serum glucose observed in pigs treated chronically with pGH is due to an increase in hepatic glucose output or to an impairment in glucose clearance. Barrows (n = 4 per treatment) were treated with pituitary derived pGH (ppGH), recombinant pGH analog (rpGH) or vehicle. Pigs were treated for 28 d by daily i.m. injections. Insulin tolerance and glucose tolerance tests (GTT) were performed on d 19 and 21, respectively, following treatment with pGH. Glucose turnover was quantified on d 28 using [6-3H]glucose. Chronically treating pigs with pGH resulted in a significant decrease (26%; P less than .05) in glucose clearance, as determined by the GTT. Glucose clearance was affected similarly by ppGH and rpGH. Intra-arterial glucose infusion markedly increased plasma insulin concentration in pGH-treated pigs. Peak plasma insulin response was 87% and 58%, respectively, higher (P less than .05) in ppGH- and rpGH-treated than in control pigs. Insulin infusion elicited a marked hypoglycemia in pigs; however, the extent and duration of hypoglycemia were significantly less in pGH-treated pigs (ppGH or rpGH). Glucose production rates were 23% higher (P = .085) in ppGH-treated than in control pigs. These results establish that the hyperglycemia induced by pGH is the result of an increase in hepatic glucose output and a concurrent impairment in glucose clearance.     

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.     

The effects of the beta-adrenergic agonist salbutamol on meat quality in pigs

The beta-adrenergic agonist Salbutamol was administered to pigs at 3 ppm in the feed between weaning and slaughter at 85 kg. Growth rate was not affected by Salbutamol. Treated pigs had a higher dressing percentage (2.6%) and produced carcasses that were less fat (17%) and had longissimus (LD) muscles of larger (11%) cross-sectional area. They also had smaller livers that contained less glycogen. The thinner backfat in treated animals was less firm and tended to separate from the underlying lean. However, these changes were attributable solely to the reduced fatness and there was no direct effect of Salbutamol. There were no differences in pH 45 min postmortem, percentage drip loss during storage or reflectance value of the LD between the two groups, indicating no greater propensity for Salbutamol-treated pigs to develop pale, soft, exudative muscle. However, treated pigs had higher final pH values in the muscles; this was reflected in slightly reduced hue and saturation values. These results suggest that the propensity of the pigs to develop dark, firm, dry meat was slightly increased. Salbutamol-treated pigs produced LD muscles that were slightly tougher (22%), had reduced concentration of heme pigments in the muscle, reduced plasma glucose and increased plasma creatine phosphokinase activity. Salbutamol improved lean meat yield but slightly increased the potential to produce dark, firm, dry meat and reduced tenderness.     

Effect of colostral fat level on fat deposition and plasma metabolites in the newborn pig

The effects of colostral fat level on fat deposition and plasma concentrations of glucose, insulin, and free fatty acids (FFA) were determined in 28 newborn pigs during the first postnatal day. Soon after birth, pigs were allotted to four treatments groups. Group 1 was killed at birth. The remaining pigs were fed intragastrically sow colostrum that contained high (10.2%; HFC), normal (4.8%; NFC) or low (1.0%; LFC) levels of total fat at the rate of 15 to 18 g/kg birth weight at 65- to 70-min intervals. A total of 21 feedings was provided and pigs were killed 1 h after the last feeding. Body fat deposition increased linearly (P less than .01) with the amount of ingested fat by .32 (+/- .04) g per 1-g increase in fat intake. Fatty acid composition of the pigs changed toward that of the colostrum with increased fat in colostrum. More liver glycogen was lost (P less than .01) in pigs given LFC. Plasma concentrations of glucose and insulin were similar in pigs fed HFC and NFC. After the 11th feeding (14 h postnatal), LFC resulted in lower plasma glucose concentrations (P less than .05) than HFC or NFC. Plasma insulin concentrations also were lower in pigs fed LFC. Plasma FFA concentrations remained unchanged in pigs fed LFC but increased with both fat content in colostrum (P less than .05) and time (P less than .05) in the other two groups. Colostral fat plays a major role in the supply of energy and in glucose homeostasis in the neonatal pig.     

Identification of serum stress biomarkers in pigs housed at different stocking densities

Eight Duroc×(Landrace×Large White) male pigs housed at a stocking rate of 0.50m(2)/pig were subjected to a higher stocking rate of 0.25m(2)/pig (higher density, HD) for two 4-day periods over 26 days. Using biochemical and proteomic techniques serum and plasma samples were examined to identify potential biomarkers for monitoring stress due to HD housing. HD housed pigs showed significant differences (P<0.001) in total cholesterol and low density lipoprotein-associated cholesterol, as well as in concentrations of the pig-major acute phase protein (Pig-MAP) (P=0.002). No differences were observed in serum cortisol or other acute phase proteins such as haptoglobin, C-reactive protein or apolipoprotein A-I. HD-individuals also showed an imbalance in redox homeostasis, detected as an increase in the level of oxidized proteins measured as the total plasma carbonyl protein content (P<0.001) with a compensatory increase in the activity of the antioxidant enzyme glutathione peroxidase (P=0.012). Comparison of the serum proteome yielded a new potential stress biomarker, identified as actin by mass spectrometry. Cluster analysis of the results indicated that individuals segregated into two groups, with different response patterns, suggesting that the stress response depended on individual susceptibility.     

Pharmacokinetics and lung tissue concentrations of tulathromycin in swine

The absolute bioavailability and lung tissue distribution of the triamilide antimicrobial, tulathromycin, were investigated in swine. Fifty-six pigs received 2.5 mg/kg of tulathromycin 10% formulation by either intramuscular (i.m.) or intravenous (i.v.) route in two studies: study A (10 pigs, i.m. and 10 pigs, i.v.) and study B (36 pigs, i.m.). After i.m. administration the mean maximum plasma concentration (C(max)) was 616 ng/mL, which was reached by 0.25 h postinjection (t(max)). The mean apparent elimination half-life (t(1/2)) in plasma was 75.6 h. After i.v. injection plasma clearance (Cl) was 181 mL/kg.h, the volume of distribution at steady-state (V(ss)) was 13.2 L/kg and the elimination t(1/2) was 67.5 h. The systemic bioavailability following i.m. administration was >87% and the ratio of lung drug concentration for i.m. vs. i.v. injection was > or =0.96. Following i.m. administration, a mean tulathromycin concentration of 2840 ng/g was detected in lung tissue at 12 h postdosing. The mean lung C(max) of 3470 ng/g was reached by 24 h postdose (t(max)). Mean lung drug concentrations after 6 and 10 days were 1700 and 1240 ng/g, respectively. The AUC(inf) was 61.4 times greater for the lung than for plasma. The apparent elimination t(1/2) for tulathromycin in the lung was 142 h (6 days). Following i.m. administration to pigs at 2.5 mg/kg body weight, tulathromycin was rapidly absorbed and highly bioavailable. The high distribution to lung and slow elimination following a single dose of tulathromycin, are desirable pharmacokinetic attributes for an antimicrobial drug indicated for the treatment of respiratory disease in swine.