Tumor necrosis factor-alpha, interleukin-6, serum amyloid A, haptoglobin, and cortisol concentrations in sows following intramammary inoculation of Escherichia coli

OBJECTIVE: To determine whether concentrations of proinflammatory cytokines, acute-phase proteins, and cortisol differ at parturition among 3 categories of sows (noninoculated, clinically affected and nonaffected following intramammary inoculation with Escherichia coll). ANIMALS: 16 sows. PROCEDURE: Sows were allocated to inoculated (n = 12) or noninoculated (4) groups. Inoculated sows received intramammary administration of E coli (serotype O127) during the 24-hour period preceding parturition. Blood samples were collected from noninoculated and inoculated sows for 3 consecutive days within 3 to 11 days before farrowing and inoculation. Samples were also collected 0, 24, 48, 72, and 96 hours after farrowing and inoculation. Inoculated sows were further categorized as affected (4 sows) or nonaffected (8 sows) based on clinical signs of disease. Serum tumor necrosis factor (TNF)-alpha, plasma interleukin (IL)-6, and serum amyloid A (SAA) concentrations were measured by use of ELISA; serum haptoglobin concentration was assayed by use of a hemoglobin-binding method; and plasma cortisol concentration was determined by use of radioimmunoassay. RESULTS: Plasma or serum concentrations of TNF-alpha, IL-6, and SAA of both categories of inoculated sows were significantly increased by 24 hours after intramammary inoculation of E coli, compared with concentrations in noninoculated sows. Concentrations of serum TNF-alpha and plasma IL-6 were significantly higher in inoculated sows that developed clinical mastitis than in nonaffected inoculated sows. CONCLUSIONS AND CLINICAL RELEVANCE: Concentrations of TNF-alpha and IL-6 are promising markers for the identification of periparturient sows with subclinical coliform mastitis. Identification of such sows should help improve the health and survival of piglets.     

Changes in various metabolic parameters in blood and milk during experimental Escherichia coli mastitis for primiparous Holstein dairy cows during early lactation

Background:The objective of this study was to characterize the changes in various metabolic parameters in blood and milk during IMI challenge with Escherichia coli(E.coli) for dairy cows during early lactation.Thirty,healthy primiparous Holstein cows were infused(h = 0) with-20-40 cfu of live ? coli into one front mammary quarter at ~4-6wk in lactation.Daily feed intake and milk yield were recorded.At-12,0,3,6,12,18,24,36,48,60,72,96,108,120,132,144,156,168,180 and 192 h relative to challenge rectal temperatures were recorded and quarter foremilk was collected for analysis of shedding of E.coli.Composite milk samples were collected at-180,-132,-84,-36,-12,12,24,36,48,60,72,84,96,132 and 180 h relative to challenge(h = 0) and analyzed for lactate dehydrogenase(LDH),somatic cell count,fat,protein,lactose,citrate,beta-hydroxybutyrate(BHBA),free glucose(fglu),and glucose-6-phosphate(G6P).Blood was collected at-12,0,3,6,12,18,24,36,60,72,84,132 and 180 h relative to challenge and analyzed for plasma non-esterified fatty acids(NEFA),BHBA and glucose concentration.A generalized linear mixed model was used to determine the effect of IMI challenge on metabolic responses of cows during early lactation.Results:By 12 h,E.coli was recovered from challenged quarters and shedding continued through 72 h.Rectal temperature peaked by 12 h post-challenge and returned to pre-challenge values by 36 h post-IMI challenge.Daily feed intake and milk yield decreased(P 0.05) by 1 and 2 d,respectively,after mastitis challenge.Plasma BHBA decreased(12 h;P 0.05) from 0.96 ± 1.1 at 0 h to 0.57 ±0.64 mmol/L by 18 h whereas concentration of plasma NEFA(18 h) and glucose(24 h) were significantly greater,11 and 27%,respectively,after challenge.In milk,fglu,lactose,citrate,fat and protein yield were lower whereas yield of BHBA and G6 P were higher after challenge when compared to pre-challenge values.Conclusions:Changes in metabolites in blood and milk were most likely associated with drops in feed intake and milk yield.However,the early rise in plasma NEFA may also signify enhanced adipose tissue lipolysis.Lower concentrations of plasma BHBA may be attributed to an increase transfer into milk after IMI.Decreases in both milk lactose yield and%after challenge may be partly attributed to reduced conversion of fglu to lactose.Rises in G6 P yield and concentration in milk after challenge(24 h) may signify increased conversion of fglu to G6 P.Results identify changes in various metabolic parameters in blood and milk after IMI challenge with E.coli in dairy cows that may partly explain the partitioning of nutrients and changes in milk components after IMI for cows during early lactation.     

Changes in various metabolic parameters in blood and milk during experimental Escherichia coli mastitis for primiparous Holstein dairy cows during early lactation

Background

The objective of this study was to characterize the changes in various metabolic parameters in blood and milk during IMI challenge with Escherichia coli (E. coli) for dairy cows during early lactation. Thirty, healthy primiparous Holstein cows were infused (h = 0) with ~20-40 cfu of live E. coli into one front mammary quarter at ~4-6 wk in lactation. Daily feed intake and milk yield were recorded. At –12, 0, 3, 6, 12, 18, 24, 36, 48, 60, 72, 96, 108, 120, 132, 144, 156, 168, 180 and 192 h relative to challenge rectal temperatures were recorded and quarter foremilk was collected for analysis of shedding of E. coli. Composite milk samples were collected at -180, -132, -84, -36, -12, 12, 24, 36, 48, 60, 72, 84, 96, 132 and 180 h relative to challenge (h = 0) and analyzed for lactate dehydrogenase (LDH), somatic cell count, fat, protein, lactose, citrate, beta-hydroxybutyrate (BHBA), free glucose (fglu), and glucose-6-phosphate (G6P). Blood was collected at -12, 0, 3, 6, 12, 18, 24, 36, 60, 72, 84, 132 and 180 h relative to challenge and analyzed for plasma non-esterified fatty acids (NEFA), BHBA and glucose concentration. A generalized linear mixed model was used to determine the effect of IMI challenge on metabolic responses of cows during early lactation.

Results

By 12 h, E. coli was recovered from challenged quarters and shedding continued through 72 h. Rectal temperature peaked by 12 h post-challenge and returned to pre-challenge values by 36 h post-IMI challenge. Daily feed intake and milk yield decreased (P <0.05) by 1 and 2 d, respectively, after mastitis challenge. Plasma BHBA decreased (12 h; P <0.05) from 0.96 ± 1.1 at 0 h to 0.57 ± 0.64 mmol/L by 18 h whereas concentration of plasma NEFA (18 h) and glucose (24 h) were significantly greater, 11 and 27%, respectively, after challenge. In milk, fglu, lactose, citrate, fat and protein yield were lower whereas yield of BHBA and G6P were higher after challenge when compared to pre-challenge values.

Conclusions

Changes in metabolites in blood and milk were most likely associated with drops in feed intake and milk yield. However, the early rise in plasma NEFA may also signify enhanced adipose tissue lipolysis. Lower concentrations of plasma BHBA may be attributed to an increase transfer into milk after IMI. Decreases in both milk lactose yield and % after challenge may be partly attributed to reduced conversion of fglu to lactose. Rises in G6P yield and concentration in milk after challenge (24 h) may signify increased conversion of fglu to G6P. Results identify changes in various metabolic parameters in blood and milk after IMI challenge with E. coli in dairy cows that may partly explain the partitioning of nutrients and changes in milk components after IMI for cows during early lactation.     

Changes in some factors of the innate immunity and serum zinc and iron concentrations in pigs following intravenous administration of Escherichia coli lipopolysaccharide

The changes in some factors of the innate immunity (phagocytosis, complement, lysozyme); haematological parameters-leukocytes, erythrocytes, differential white blood cell counts, haemoglobin, haematocrit and the serum concentrations of the microelements zinc and iron in six 2- to 3-months-old female piglets after the intravenous administration of lipopolysaccharide from Escherichia coli 0111:B4 were determined. It was found out that 1 h after the administration of lipopolysaccharide at the dosage rate of 10 microg/kg body weight resulted in a decrease in the phagocytic parameters, i.e. the phagocytic number and the index of phagocytic activity, which was followed by an increase in their values between post treatment hours 2 and 4. The leukocyte counts had decreased by hour 2 after the injection, but thereafter increased, and at post treatment hour 72, a leukocytosis was observed. The differential white blood cell counts were characterized by a shift to the left between hours 2 and 4 and a statistically significant increase in lymphocyte counts at hour 48 of the experiment. The serum zinc concentrations were increased an hour after the lipopolysaccharide application; after which their average values were lower. The haemolytic activities (CH50) of the classical and the alternative pathways of complement activation decreased. The haemolytic activity (CH50) for the classical pathway began to increase at hour 48 following the treatment. Significant changes were not observed in lysozyme activity, serum iron concentrations or the related haematological parameters (erythrocytes and haemoglobin).     

Effects of intravenous infusion of lipopolysaccharide on plasma micromineral, magnesium, and cytokine concentrations and serum cortisol concentrations in lactating goats

OBJECTIVE: To assess the effects of various doses of lipopolysaccharide (LPS) administered IV on plasma microminerals, magnesium, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-6 concentrations and serum cortisol concentrations in lactating goats. ANIMALS: 6 lactating goats. PROCEDURES: Goats were allotted to 3 LPS-treatment groups: control (0 microg/kg), low LPS (10 microg/kg), and high LPS (50 microg/kg). Rectal temperatures and behaviors of goats were recorded immediately before a 10-minute IV infusion of LPS and at 0.5, 1, 2, 4, 6, 8, and 24 hours after infusion. Blood samples were obtained before IV infusion and at 0.5, 1, 2, 4, 6, 8, and 24 hours after infusion. Plasma zinc, copper, iron, and magnesium concentrations were determined by atomic absorption spectrometry; plasma TNF-alpha and IL-6 concentrations were measured by use of an ELISA; and serum cortisol concentrations were determined by use of a radioimmunoassay. RESULTS: A monophasic fever developed in low-LPS and high-LPS groups. In the low-LPS and high-LPS group, plasma zinc concentrations decreased at 6 hours after infusion; compared with control groups. Plasma iron concentrations were lower at 24 hours after infusion in low-LPS and high-LPS groups than in the control group. Plasma TNF-alpha and IL-6 concentrations were higher in low-LPS and high-LPS groups than in the control group at 1, 2, and 4 hours after infusion. In low-LPS and high-LPS groups, serum cortisol concentrations increased from 0.5 hours onward and peaked at 1 (high-LPS group) and 2 (low-LPS group) hours after infusion. CONCLUSIONS AND CLINICAL RELEVANCE: Following IV infusion of LPS, the immune system is activated, which might affect micromineral homeostatic regulation and, subsequently, the metabolic health of lactating goats.     

Acute phase response in reindeer after challenge with Escherichia coli endotoxin

The serum concentrations of two acute phase proteins (APPs), haptoglobin (Hp) and serum amyloid-A (SAA), were monitored in reindeer after challenge with endotoxin. Four adult female reindeer received either 0.1 μg/kg Escherichia coli 0111:B4 lipopolysaccharide B or saline solution intravenously. At the second challenge, the treatments were reversed. In addition to the APPs, changes in blood chemistry and rectal temperature were monitored. The endotoxin challenge caused a significant increase in SAA (peak 48 h) and a sharp decrease (8–12 h) of serum iron concentrations in all animals. The mean Hp concentration increased at 8 h and remained elevated until 48 h, but no statistically significant differences were found. This investigation demonstrates that challenge with a single-bolus dose of E. coli endotoxin can activate the acute phase response (APR) and SAA appears to be a more sensitive indicator of the APR than Hp during bacterial infection in reindeer.     

The effect of age on erythrocyte magnesium concentrations of dairy cows during late pregnancy and early lactation

Blood samples were taken at weekly intervals from fifty four dairy cows (mainly Friesians and Jerseys) during the periods 8 weeks before and 8 weeks after calving. The cows were divided into two age groups; Group 1 consisting of 26 cows 2 1/2 to 4 years old and Group 2 consisting of 28 cows over 4 years old.The changes in erythrocyte magnesium (EMg) and plasma magnesium (PMg) concentrations before and after calving were expressed as the slope of each blood parameter regressed on weeks. The post-partum EMg concentration slope (increase) was greater (P<0.05) in the older cows than in the young ones. The older cows also had higher (P<0.05) mean EMg concentrations than the young cows. Between cow EMg concentration variations were significant (P<0.05) in both age groups while the weekly EMg concentration variations were only significant (P<0.05) in the older cows after calving. Age did not influence the changes in PMg concentrations before or after calving. Nor did the PMg concentrations vary significantly either between cows or between weeks.     

Oxidative status during late pregnancy and early lactation in dairy cows

In the last few years, the detection of free radical damage and the body's defences against it have become increasingly important in clinical medicine as a complementary tool in the evaluation of metabolic status. The aim of this study was to evaluate, under field conditions, the anti-oxidant status of healthy cows during late pregnancy and lactation onset using two parameters: (1) plasma levels of malondialdehyde (MDA), a degradation product of lipid peroxidation, and (2) total antioxidant status (TAS). Results were compared with those obtained in another group of cows with lesser metabolic demands. We also investigated possible relationships between antioxidant status markers and other relevant blood parameters. Our results confirmed the characteristic metabolic changes associated with late pregnancy and early lactation. MDA and TAS provided an accurate reflection of the internal physiological status of the animal. The data indicated increased lipid peroxidation around parturition, but with wide individual variations that may be attributable not only to the physiological stage but also to unknown factors that will have to be further considered in future studies.     

高精料诱导的SARA对泌乳期山羊血液和瘤胃液中皮质醇的影响

选择7只装有永久性瘤胃瘘管的泌乳中期山羊,2×2拉丁方设计,分别饲喂精粗比为6∶4和4∶6的饲料,通过饲喂精粗比6∶4饲料建立泌乳期山羊瘤胃亚急性酸中毒(subacute ruminal acidosis, SARA)模型,研究SARA时山羊血液和瘤胃液中皮质醇浓度、肝脏皮质醇受体(glucocorticoid receptor, GR)mRNA表达及其他相关指标的变化。结果表明,精粗比6∶4日粮饲喂2周后成功诱导SARA状态(SARA组),采食后瘤胃液pH值低于5.8持续时间约6 h,而精粗比为4∶6组山羊瘤胃液pH均高于6.0 (对照组)。高精料日粮处理对瘤胃pH和乳酸以及瘤胃液和血浆内的脂多糖、皮质醇浓度有显著性影响(P<0.05),采食前SARA组山羊瘤胃液中乳酸浓度显著高于对照组(P<0.05),采食后0~4 h乳酸含量下降,6~10 h时逐渐增加并极显著高于对照组(P<0.01);2组间瘤胃液中脂多糖浓度无显著性差异(P>0.05),SARA组血浆脂多糖浓度在采食前和采食后6 h均显著高于对照组(P<0.05);采食前SARA组山羊血液中皮质醇浓度高于对照组(P=0.05),但采食后6 h两组间无显著差异(P>0.05); 2组山羊瘤胃液中皮质醇浓度在采食后2,4和6 h分别显著高于对照组(P<0.05),但在采食前和采食后10 h无显著差异(P>0.05)。Real-time PCR结果显示,SARA组山羊肝脏中GR mRNA表达显著下调(P<0.05)。本研究结果显示,泌乳期山羊发生SARA时糖皮质激素水平升高,负反馈下调肝脏GR的表达水平,提示SARA时机体处于应激状态,可能引起肝脏的物质代谢和营养物质重分配的改变。     

Comparison between blood serum and salivary cortisol concentrations in horses using an adrenocorticotropic hormone challenge

Reasons for performing study: In horses, serum cortisol concentration is considered to provide an indirect measurement of stress. However, it includes both free and bound fractions. The sampling method is also invasive and often stressful. This is not the case for salivary cortisol, which is collected using a more welfare‐friendly method and represents a part of the free cortisol fraction, which is the biologically active form. Objectives: To compare salivary and serum cortisol assays in horses, in a wide range of concentrations, using an adrenocorticotropic hormone (ACTH) stimulation test, in order to validate salivary cortisol for stress assessment in horse. Methods: In 5 horses, blood samples were drawn using an i.v. catheter. Saliva samples were taken using swabs. Cortisol was assayed by radioimmunoassay. All data were treated with a regression method, which pools and analyses data from multiple subjects for linear analysis. Results: Mean ± s.d. cortisol concentrations measured at rest were 188.81 ± 51.46 nmol/l in serum and 1.19 ± 0.54 nmol/l in saliva. They started increasing immediately after ACTH injection and peaks were reached after 96 ± 16.7 min in serum (356.98 ± 55.29 nmol/l) and after 124 ± 8.9 min in saliva (21.79 ± 7.74 nmol/l, P<0.05). Discharge percentages were also different (225% in serum and 2150% in saliva, P<0.05). Correlation between serum and salivary cortisol concentrations showed an adjusted r²= 0.80 (P<0.001). The strong link between serum and salivary cortisol concentrations was also estimated by a regression analysis. Conclusions: The reliability of both RIAs and regression found between serum and salivary cortisol concentrations permits the validation of saliva‐sampling as a noninvasive technique for cortisol level assessment in horses.     

Changes in serum concentrations of luteinizing hormone and follicle-stimulating hormone following injection of gonadotropin-releasing hormone during pregnancy and after parturition in mares

High concentrations of estrogens in the peripheral circulation during late gestation inhibit synthesis of LH and markedly reduce pituitary content of LH at the end of pregnancy in most domestic species. Because blood concentrations of estrogen peak shortly before mid-gestation in the mare and then gradually decrease until parturition, we hypothesized that pituitary content of LH may increase during late gestation. To test this hypothesis 10 horse mares were challenged with a maximally stimulatory dose (2 micrograms/kg) of GnRH on d 240 and 320 of gestation and d 3 after parturition. A separate group of four mares were treated with GnRH on d 2 or 3 estrus. Blood samples were collected at -2, -1, 0, .25, .5, .75, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 7 and 8 h relative to injection of GnRH and serum was analyzed for concentration of LH and FSH. Basal serum concentration and total quantity of LH released after GnRH stimulation (assessed by determining the area under the response curve) were not different on d 240 and 320 of gestation or on d 3 after parturition (12.5 +/- 3.5, 5.7 +/- 1.5 and 29.1 +/- 12.1 ng.min/ml, respectively) and were less (P less than .05) than on d 3 of estrus (311.0 +/- 54.0 ng.min/ml). There was little difference in the basal serum concentration of FSH at any of the time points examined. In contrast, GnRH-induced release of FSH continually decreased (P less than .05) from d 240 of gestation (559.8 +/- 88.9 ng.min/ml) to d 3 of estrus (51.8 +/- 6.2 ng.min/ml).(ABSTRACT TRUNCATED AT 250 WORDS)     

The influence of intramammary lipopolysaccharide infusion on serum Ca, P, vitamin D, cytokines and cortisol concentrations in lactating sows

Ten multiparous lactating sows were used to investigate whether intramammary infusion of lipopolysaccharides (LPS; Escherichia coli 0111:B4; 2.0 microg/kg of body weight) would affect the circulating concentrations of Ca, P, 25-hydroxyvitamin D (25-OHD), tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and cortisol. The sows were randomly allotted to either control group (control) or LPS-treated group with five individuals per group and were infused with either physiological saline solution or LPS solution. The rectal temperature and udder quarter appearance were recorded at 0 (just before infusion), 1, 3, 7, 12 or 24 h after infusion. Blood samples were taken at 0, 1, 3, 7, 12 or 24 h after infusion. Before infusion, the rectal temperatures of all sows were below 39.2 degrees C. At 3 and 7 h after infusion, the sows in the LPS group had a rectal temperature over 39.4 degrees C. At 24 h after infusion, the rectal temperatures returned to pre-infusion levels. Serum Ca and P concentrations in the LPS group decreased (P < 0.05) after LPS infusion compared with the control group at 1 h after infusion. No significant differences (P > 0.05) in the concentrations of 25-OHD were observed between groups control and LPS at any sampling time. Increased (P < 0.01) concentrations of serum TNF-alpha, IL-6 and cortisol were observed in the LPS group compared with the control group at 3 and 7 h after infusion respectively. In conclusion, the elevation of serum concentrations of TNF-alpha, IL-6 and cortisol and the alterations of circulating concentrations of Ca and P following LPS infusion indicate that the immune system has been activated and immune activation may affect macromineral homeostatic regulation, which might have important implications for metabolic health of lactating sows. Lowered serum Ca and P following immune activation also shows a causative mechanism whereby immune activation increases the risk of secondary disorders such as mastitis-metritis-agalactia syndrome. However, immune activation did not affect circulating concentrations of vitamin D metabolites.     

Apramycin: minimal inhibitory concentrations for avian Escherichia coli and serum levels after intramuscular injection in turkeys

The minimal inhibitory concentrations (MIC) of apramycin, a unique aminocyclitol antibiotic, for 100 Escherichia coli isolates recovered from clinical cases of avian colibacillosis were determined using the agar dilution method. All isolates were inhibited at apramycin concentration of 8.0 micrograms/ml; 90 and 50% of the isolates were inhibited at 6.6 and 3.4 micrograms/ml, respectively. A commercial injectable product containing 200 mg apramycin/ml was administered intramuscularly (i.m.) to groups of 6- and 12-week-old turkeys at 10, 15 and 20 mg/kg. Apramycin was quickly absorbed from the i.m. injection site. Mean peak serum drug concentrations were reached 1 h after treatment and were 19.5, 27.5 and 36.0 micrograms/ml, respectively. The serum elimination half-life (t 1/2) of the drug ranged between 1.75 h for the 10 mg/kg dose and 2.5 h for the 20 mg/kg dose. Very low concentrations of the drug were found 24 h after treatment. Duration of serum apramycin concentrations in relation to the MIC, dose, and age of birds was determined.     

The effects of age on the erythrocyte sodium and potassium concentrations of dairy cows during late pregnancy and early lactation

Blood samples were taken at weekly intervals from 54 dairy cows (mainly Friesians and Jerseys) during the periods 8 weeks before and 8 weeks after calving. The cows were divided into two age groups; group 1 consisting of 26 cows aged 2 1/2 years and group 2 consisting of 28 cows aged 5–9 years. The changes in the erythrocyte sodium (ENa) and the erythrocyte potassium (EK) concentrations before and after calving were expressed as the slopes for each component regressed on weeks. In the older cows the concentration of ENa decreased (p<0.05) while that of EK increased (p<0.05) after calving. Both the ENa and EK concentrations varied significantly (p<0.01) between cows in the two age groups. The prepartum and postpartum ENa and the postpartum EK concentrations varied significantly (p<0.05) between weeks. EK type did not influence the changes in ENa or EK concentrations before or after calving.     

Activation of the ovine hypothalamic-pituitary-adrenal axis and febrile response by interleukin-6: A comparative study with bacterial lipopolysaccharide endotoxin

Sheep were subjected to immune challenge with either recombinant human interleukin-6 (rhIL-6; 2.0 μg/kg; n = 5), Escherichia coli lipopolysaccharide (LPS) endotoxin (400 ng/kg; n = 7), or saline (n = 6) to determine if IL-6 activates the febrile and hypothalamic-pituitary-adrenal axis (HPAA) responses in sheep, and to compare these responses with those associated with endotoxemia. Blood was collected over time to measure plasma adrenocorticotropic hormone (ACTH) and serum cortisol concentrations as indicators of HPAA activity. Unlike LPS, rhIL-6 was not pyrogenic in sheep at this challenge dose. In contrast, rhIL-6 elicited ACTH and cortisol responses that peaked earlier than those induced by LPS. These results suggest that this dose of IL-6, alone, is not sufficient to elicit the febrile response in sheep, however, it is a potent activator of the ovine HPAA response.     

Effects of fish oil supplementation on the performance and the immunological, adrenal, and somatotropic responses of weaned pigs after an Escherichia coli lipopolysaccharide challenge

Seventy-two crossbred pigs (7.58 +/- 0.30 kg BW) weaned at 28 +/- 3 d of age were used to investigate the effects of fish oil supplementation on pig performance and on immunological, adrenal, and somatotropic responses following an Escherichia coli lipopolysaccharide (LPS) challenge in a 2 x 2 factorial design. The main factors consisted of diet (7% corn oil [CO] or 7% fish oil [FO]) and immunological challenge (LPS or saline). On d 14 and 21, pigs were injected intraperitoneally with either 200 microg/kg BW of LPS or an equivalent amount of sterile saline. Blood samples were collected 3 h after injection for analysis of interleukin-1beta (IL-1beta), prostaglandin E2 (PGE2), cortisol, growth hormone (GH), and insulin-like growth factor (IGF)-I. On d 2 after LPS challenge, peripheral blood lymphocyte proliferation (PBLP) was determined. Lipopolysaccharide challenge decreased ADG (487 vs. 586 g; P < 0.05) and ADFI (as-fed, 776 vs. 920 g; P < 0.05) from d 14 to 21 and ADG (587 vs. 652 g; P < 0.10) from d 21 to 28. Fish oil improved ADG (554 vs. 520 g; P < 0.10) and ADFI (891 vs. 805 g; P < 0.10) from d 14 to 21. On d 14, LPS challenge x diet interactions were observed for IL-1beta (P < 0.10), PGE2 (P < 0.001), and cortisol (P < 0.05) such that these measurements responded to the LPS challenge to a lesser extent (IL-1beta: 93 vs. 114 pg/mL, P < 0.05; PGE2: 536 vs. 1,285 pg/mL, P < 0.001; cortisol: 143 vs. 206 ng/mL, P < 0.05) in pigs receiving the FO diet than in pigs fed the CO diet. In contrast, among LPS-treated pigs, pigs fed the FO diet had higher IGF-I (155 vs. 101 ng/mL; P < 0.10) than those fed the CO diet. On d 21 among LPS-treated pigs, pigs fed FO had lower IL-1beta (70 vs. 84 pg/mL; P < 0.10) and cortisol (153 vs. 205 ng/mL; P < 0.05) than those fed CO. Pigs fed FO had lower PGE2 (331 vs. 444 pg/mL; P < 0.05) and higher IGF-I (202 vs. 171 ng/mL; P < 0.10) compared with those fed CO. Lipopolysaccharide challenge decreased GH (0.27 vs. 0.33 ng/mL; P < 0.05) on d 14, whereas it had no effect on GH on d 21. During both LPS challenge periods, the challenge increased PBLP when these cells were incubated with 8 (1.46 vs. 1.32; P < 0.10) or 16 microg/mL (1.46 vs. 1.30; P < 0.05) of concanavalin A. Fish oil had no effect on PBLP. These results suggest that FO alters the release of proinflammatory cytokines, which might lead to improved pig performance during an immunological challenge.     

Variation of inflammatory dynamics and mediators in primiparous cows after intramammary challenge with Escherichia coli

ABSTRACT: The objective of the current study was to investigate (i) the outcome of experimentally induced Escherichia coli mastitis in primiparous cows during early lactation in relation with production of eicosanoids and inflammatory indicators, and (ii) the validity of thermography to evaluate temperature changes on udder skin surface after experimentally induced E. coli mastitis. Nine primiparous Holstein Friesian cows were inoculated 24 ± 6 days (d) after parturition in both left quarters with E. coli P4 serotype O32:H37. Blood and milk samples were collected before and after challenge with E. coli. The infrared images were taken from the caudal view of the udder following challenge with E. coli. No relationship was detected between severity of mastitis and changes of thromboxane B2 (TXB2), leukotriene B4 (LTB4) and lipoxin A4 (LXA4). However, prostaglandin E2 (PGE2) was related to systemic disease severity during E. coli mastitis. Moreover, reduced somatic cell count (SCC), fewer circulating basophils, increased concentration of tumor necrosis factor-α (TNF-α) and higher milk sodium and lower milk potassium concentrations were related to systemic disease severity. The thermal camera was capable of detecting 2-3°C temperature changes on udder skin surface of cows inoculated with E. coli. Peak of udder skin temperature occurred after peak of rectal temperature and appearance of local signs of induced E. coli mastitis. Although infrared thermography was a successful method for detecting the changes in udder skin surface temperature following intramammary challenge with E. coli, it did not show to be a promising tool for early detection of mastitis.     

Mechanical properties of the ovine cervix during pregnancy, labour and immediately after parturition

The stretch modulus (stress/strain) of strips of ovine cervical tissue in vitro was measured at different stages of gestation. A decrease in stretch modulus implies softening of the tissue. There was a gradual but progressive reduction in the stretch modulus with advancing pregnancy between 30 and 140 days gestation with a marked increase between 140 days gestation and the onset of labour (P less than 0.005). After the first trimester, the uterine end of the cervix was usually more distensible than the vaginal end. No further reduction in the stretch modulus of the cervix occurred between labour and delivery of the fetus. The results of this study suggest that while there is some softening of the ovine cervix during pregnancy, most of the softening takes place immediately prior to the onset of labour and delivery of the fetus.