Interleukin-6 as a Milk Marker of Clinical and Subclinical Intramammary Infections (IMI) in Cows Caused by Streptococcus spp

The aim of the study was to evaluate the concentrations of Interleukin-6 (IL-6) in milk and serum of healthy cows (HE) and cows with mastitis caused by Streptococcus spp. The blood and milk samples were obtained from Holstein-Friesian cows (Lublin region, Poland). A total of 43 milk and serum samples from 28 cows with mastitis and 15 healthy cows were selected for study. IL-6 levels in milk from HE cows ranged from 6.09-80.24 pg/mL (median 26.6 pg/mL) and were significantly lower than in milk from both cows with clinical and subclinical mastitis (487.09 pg/mL vs. 26.6 pg/mL in CM, p < 0.001; and 165.31 pg/mL vs. 26.6 pg/mL in SCM, p < 0.001). The IL-6 concentration in the serum of HE was not significantly different from the serum IL-6 of the entire group of mastitis cows, regardless of whether the inflammation proceeded in a clinical or subclinical form (44.37 pg/mL vs. 78.09 pg/mL; 128.29 pg/mL vs. 78.09 pg/mL, respectively). The present study indicates that cows with mastitis caused by Streptococcus spp. develop a local immune response in the mammary gland in response to the pathogen. Monitoring of IL-6 levels in milk can allow early detection of mastitis, which is especially important in cases of subclinical inflammation.

Cytokine inflammatory response in dairy cows with mastitis caused by Streptococcus agalactiae

Introduction

The aim of the study was evaluation of the concentrations of interleukin (IL)-1β, IL-8, IL-12β and tumour necrosis factor alpha (TNF-α) in the serum and milk of cows with mastitis caused by Streptococcus agalactiae.

Material and Methods

A total of 60 milk samples from diseased cows and 30 milk samples from healthy cows were included in the study. Blood and milk samples were taken from Holstein-Friesian cows from three herds (two in tie-stall and one in a free-stall housing system) in Lublin Province in Poland. The concentrations of cytokines in blood serum and quarter milk samples were determined by ELISA.

Results

The levels of IL-1β, IL-8, IL-12β and TNF-α were significantly higher in the milk of cows suffering from mastitis caused by S. agalactiae compared to the milk of healthy cows (263.03 vs 55.36 pg/mL, 298.34 vs 131.82 pg/mL, 604.10 vs 139.17 pg/mL and 460.86 vs 78.82 pg/mL, respectively). In the group of sick cows, cytokine levels were significantly higher in milk than in serum (263.03 vs 55.25 pg/mL for IL-1β, 298.34 vs 164.22 pg/mL for IL-8, 604.10 vs 70.34 pg/mL for IL-12β and 460.86 vs 104.78 pg/mL for TNF-α).

Conclusion

The results confirm the involvement of the entire bovine immune system to protect against the bacteria first locally in the udder. The response of the mammary gland to infection caused by S. agalactiae is rapid and already very strong at the beginning of the infection.

Effects of fetal number on acute phase proteins, cortisol, and hematological parameters in ewes during the periparturient period

Many subclinical diseases associated with inflammation occur in sheep during the periparturient period. Clinical symptoms are usually detected at an advanced stage of the disease; therefore, there are considerable risks of permanent health disorders in fetuses or dams. Determination of acute phase proteins (APPs) as markers of inflammation may allow for an earlier diagnosis and effective treatment. Furthermore, multi-fetus pregnancies are often associated with hematological disturbances. The study objective was to compare plasma concentrations of serum amyloid A (SAA), haptoglobin (Hp), fibrinogen (Fb), and cortisol in ewes bearing one and two fetuses in the period from 2 weeks before to 2 weeks after parturition as well as to determine hematological parameters in peripheral blood. There was an important effect of fetal number on APP and cortisol concentrations in periparturient ewes. There was a greater concentration of SAA, Hp, Fb, and cortisol in ewes bearing two fetuses compared with those bearing one fetus. Profiles for APP and cortisol concentrations and hematological parameters were similar for ewes bearing one and two fetuses, and trends were within normal reference ranges for the periparturient period. Furthermore, there were no differences in values for hematological variables between ewes bearing one and two fetuses. with there being no ewes with anemia. In summary, separate determination of the previously undefined physiological ranges of APPs and cortisol for ewes bearing one and two fetuses may facilitate diagnosis of subclinical disorders and enable comparison of laboratory test results with different reference values for ewes bearing different numbers of fetuses.

Camelina Oil Supplementation Improves Bone Parameters in Ovariectomized Rats

The aim of the present study was to determine the effect of administration of Camelina sativa oil (CO) as a source of polyunsaturated fatty acids (PUFA) on bone parameters in ovariectomized rats (OVX). Overall, 40 10-week-old healthy female Wistar rats were divided into 4 groups with 10 animals in each. Rats in the control group (SHO) were subjected to a sham operation, whereas experimental rats (OVX) were ovariectomized. After a 7-day recovery period, the SHO the rats received orally 1 mL of physiological saline for the next 6 weeks. The OVX rats received orally 1 mL of physiological saline (OVX-PhS), 5 g/kg BW (OVX-CO5), or 9 g/kg BW (OVX-CO9) of camelina oil. The use of camelina oil had a significant effect on body weight, lean mass, and fat mass. The camelina oil administration suppressed the decrease in the values of some densitometric, tomographic, and mechanical parameters of femur caused by estrogen deficiency. The CO treatment increased significantly the serum level of osteocalcin and decreased the serum level of C-terminal telopeptide of type I collagen in the OVX rats. In conclusion, camelina oil exerts a positive osteotropic effect by inhibiting ovariectomy-induced adverse changes in bones. Camelina oil supplementation can be used as an efficient method for improving bone health in a disturbed state. However, further research must be carried out on other animal species supplemented with the oil.

Analysis of the occurrence and molecular characteristics of drug-resistant strains of Enterococcus faecalis isolated from the gastrointestinal tract of insectivorous bat species in Poland: A possible essential impact on the spread of drug resistance?

Bats are poorly understood as a reservoir of multidrug-resistant strains; therefore, the aim of this study was to determine molecular characterization of multidrug-resistant Enterococcus strains isolated from bat species from Poland. A multi-stage analysis based on targeted isolation of drug-resistant strains (selective media with tetracycline, chloramphenicol, gentamicin, streptomycin, and vancomycin), determination of the phenotypic profile of drug-susceptibility using the disc diffusion method, and amplification of DNA fragments surrounding rare restriction sites (ADSRRS-fingerprinting) was used for the isolation and differentiation of strains. The applied strategy finally allowed identification of E. faecalis resistant to at least one antimicrobial in 47.2% of the single-animal group and in 46.9% of the pooled samples of bat's guano. Out of the 36 distinct isolates, 69% met the criteria of multi-drug resistance, with a dominant combination of resistance to tetracycline, erythromycin, and rifampicin. Simultaneously, 41.6% of the strains were high-level aminoglycoside resistant (HLAR). In most strains, phenotypic resistance was reflected in the presence of at least one gene encoding resistance to a given drug. Moreover, our research results show that some genes were detected simultaneously in the same strain statistically significantly more frequently. This may confirm that the spread of some genes (tetM and ermB or aph (3')-IIIa as well as gelE and aac (6')-Ie-aph (2″)-Ia or ant (6)-Ia) is associated with their common occurrence on the same mobile genetic element. To our knowledge, this is the first analysis of multidrug-resistance among E. faecalis isolated from bats. Our research demonstrates that the One Health concept is not associated exclusively with food-producing animals and humans, but other species of wildlife animals should be covered by monitoring programs as well. We confirmed for the first time that bats are an important reservoir of multi-resistant E. faecalis strains and could have a great impact on environmental resistance.

A significant number of multi-drug resistant Enterococcus faecalis in wildlife animals; long-term consequences and new or known reservoirs of resistance?

As the last link in the food chain in a complex ecosystem covering at least three different environmental spheres, species of wildlife carnivorous mammals constitute a group accumulating potential pathogens and factors resulting from human activity, including the emergence of drug resistance. Therefore, the aim of this study was to evaluate the level and range of resistance in commensal E. faecalis isolated from wildlife carnivorous mammals and genetic relationships in terms of the source of these strains as well as resistance and virulence genes. Differentiation between strains was performed based on ADSRRS-fingerprinting method. The results showed that almost half of the tested animals (48%) were carriers of at least one multidrug resistant E. faecalis strain. Moreover, 44% of MDR-positive animals showed two or three strains differing in both the genotype and the resistance phenotype. A significant percentage of strains were resistant to high-level aminoglycosides (from 20% to even 57.5%). The resistance and virulence gene profiles showed a rich panel of genes closely related to isolates from nosocomial infection and from livestock animals. The presence of the same genotypes in different hosts reflects not only a possible transfer of genes between E. faecalis strains but also exchange of strains between animals. The obtained results reflect a very high level of contamination of animals that are not subjected to targeted antibiotic therapy, which may suggest the degree of pollution of the environment. Wildlife animals and their environment can be a link closing the circulation cycle of genes and even epidemiologically important strains; therefore, there is a high risk that this pool will never run out and will be maintained at a high level.

Adropin, nesfatin-1 and angiotensin II receptor expression in the abdominal aorta in ovariectomized rats after nesfatin-1 treatment

The aim of the research was to assess the effect of nesfatin-1 on the structure, flexibility parameters, and expression of adropin, nesfatin-1, and angiotensin II receptor type 1 (AT1R) in the abdominal aorta in ovariectomized rats. Fragments of aortas were collected after euthanasia of female sham-operated (CONT) and ovariectomized Wistar rats (EXP), which were administered intraperitoneal injection of physiological saline (CONT, n = 7; EXP-O, n = 7) or nesfatin-1 (EXP-N, n = 7) in an amount of 2 μg/kg b.w. once a day for 8 weeks. The samples of aortas were collected for measurement of elasticity as well as histomorphometric, immunohistochemical, FTIR, and Raman spectroscopy analysis. The ovariectomy caused a significant increase in the thickness of the total wall and its particular layers in the aorta, in comparison to the CONT and EXP-N groups. However, the ovariectomy led to a decrease in the amount of elastin, collagen (mature, immature collagen, collagen maturity ratio 1660 - 1690 cm^-1), and amides, with a simultaneous increase in lipids, especially in the tunica intima-media of the abdominal aorta compared to the other groups. The use of nesfatin-1 significantly increased the amount of collagen, elastin and amides with a simultaneous decrease in the amount of lipids and the expression of AT1R, adropin and nesfatin-1 in the abdominal aorta of ovariectomized rats. In conclusion, our study showed that the ovariectomy surgery induced changes in the abdominal aorta wall characteristic for aging females. Application of nesfatin-1 may prevent the negative consequences in the vessel wall structure in females in conditions of estrogen deficiency and prevent atherosclerotic changes in the cardiovascular system.

Acute-phase proteins, cortisol and haematological parameters in ewes during the periparturient period

Numerous subclinical diseases in sheep occur in the periparturient period and involve inflammatory processes; therefore, determining markers, such as acute-phase proteins (APPs), can allow an early diagnosis. Therefore, the objective of the present study was to assess changes in the plasma concentration of APPs and cortisol in clinically healthy ewes in the periparturient period for use in future studies. At the same time, haematological parameters were monitored. We showed that plasma APPs and cortisol concentrations were significantly higher in pregnant ewes than before insemination. A gradual increase in the SAA concentration was observed from the 14th day before to the day of parturition, while Hp was reduced from 2 weeks before up to 2 weeks after delivery. A significant increase in the Fb concentration was detected from the 14th day before to the 1st week after delivery. The cortisol concentration did not undergo significant changes in the periparturient period. We found an increase in the SAA and Fb concentrations and decrease in Hp in the periparturient period. The direction of the change in APPs of healthy ewes in the current study may be related to their distinct regulatory mechanisms during pregnancy. The APPs are usually altered during infection, inflammation, neoplasia, stress and trauma; therefore, knowing their reference values could help lead to an early diagnosis of subclinical forms of some diseases and pregnancy complications in ewes. The haematological analysis showed that ewes in late pregnancy and postpartum compared to dry period were under metabolic stress related to pregnancy and lactation.

Bats as a reservoir of resistant Escherichia coli: A methodical view. Can we fully estimate the scale of resistance in the reservoirs of free-living animals?

Bats are a poorly understood reservoir of pathogenic and multi-drug resistant microorganisms; therefore, the aim of the study was to analyze the presence of drug resistance among E. coli isolated from the species of bats occurring naturally in Poland. The strategy of isolation and identification of resistant strains from pooled and single-animal samples was based on selective media with cefotaxime, chloramphenicol, kanamycin and tetracycline, the use of the ADSRRS-fingerprinting method for genomic differentiation of isolates, and the classical methods of evaluation of phenotypic and genotypic resistance. Of the 78 isolated isolates confirmed as E. coli, there were 38 genetically distinct strains resistant at least to one antimicrobial. 71% of these strains met the multi-drug resistance criterion. Moreover, two different multidrug resistant strains were isolated from three single samples. The highest resistance was observed in the case of ampicillin (66%), kanamycin (84%), sulfamethoxazole/trimetoprim (61%/55% respectively), and streptomycin (50%), which in most cases was confirmed by the presence of an adequate gene. Two isolates from single hosts produced extended-spectrum beta-lactamases (bla_CTX-M-3, bla_CTX-M-15, bla_TEM-1). With the exception of tetracycline resistance, which was dominant among isolates from single animals, no significant differences in the resistance of the strains from both groups of samples were observed. Bats should not be neglected as another environmental reservoir and as an unpredictable source of potential pathogenic and multidrug resistant bacteria and should be extensively studied to predict the direction of the development and range of spreading resistance.

Changes in growth hormone secretion and leptin receptor mRNA expression under the influence of leptin and adrenocorticotropin in pituitary cells of early weaned ewe lambs

Early weaning of ewe lambs strongly stimulates the hypothalamic-pituitary-adrenal axis and is associated with suppressed growth rate despite the increased food intake. At the same time, plasma leptin concentration increases only slightly or undetectably. To better understand this atypical interdependence among somatic stress, leptin, and lamb growth rate, we analyzed impact of leptin and/or adrenocorticotropic hormone (ACTH) on growth hormone (GH) secretion as well as the effect of ACTH on mRNA expression of two splice variants of leptin receptor (LEPRa, LEPRb) in pituitary cells isolated from early weaned ewe lambs. The GH secretion under the influence of leptin and/or ACTH depended on the timing of exposure and hormone concentration. After 6 - 30 h, GH secretion increased under 10^-11 - 10^-8 M leptin (P ≤ 0.05). However, after 24 - 30 h, GH secretion significantly increased only in cells exposed to both leptin and ACTH compared to culture with leptin only. Simultaneously, there was a significant (P ≤ 0.05) decrease in leptin receptor mRNA expression under the influence of ACTH at 10^-8 - 10^-6 M after 12 - 30 and 24 - 30 h for LEPRa and LEPRb, respectively. ACTH-related downregulation of LEPR mRNA was associated with a significant (P ≤ 0.05) reduction in leptin-stimulated GH secretion, also after 24 - 30 hours. Thus, the timing of ACTH exposure, followed by decreased leptin receptor mRNA, converged with the timing of decreased GH secretion under the influence of leptin with ACTH. The ACTH-induced downregulation of LEPR mRNA therefore may underlie the decrease in GH. These results show a direct role for leptin, ACTH, and leptin receptor expression in modulation of pituitary GH secretion in early weaned ewe lambs. During the early weaning-induced stress response, the ACTH-mediated decrease in sensitivity of pituitary cells to leptin may abolish a stimulatory effect of leptin on GH secretion and explain in part, the reduction in lamb growth rate.

Transport induced inflammatory responses in horses

Deleterious response to road transport is an important problem in equine practice. It determines different physiological, immunological and metabolic changes which lead to increased susceptibility to several disorders such as pneumonia, diarrhea, colics, laminitis, injuries and rhabdomyolisis. The aim of our study was to look for possible relationships between transportation of female young and older horses over a long and short distance and an inflammatory state reflected by an increase of acute phase protein concentration, oxidative stress and muscle injury. The study was conducted on 24 cold-blooded female horses divided into four groups. Six fillies aged 6-18 months and six mares aged 10-12 years were transported over the distance of about 550 km, six fillies aged 6-18 months and six mares aged 10-12 years were transported over the distance of about 50 km. Plasma and serum were obtained from blood samples taken before transportation (T0), immediately after transportation (T1) and at an abattoir during slaughter (T2). In these samples fibrinogen, MDA, AST and CK were assessed. Fibrinogen increased in all studied groups especially in fillies after long distance transportation, where it reached 205±7.07 mg/dl before transportation, 625±35.35 mg/dl after transportation, and 790±14.14 mg/dl during slaughter. MDA concentrations rose after transportation and reached the maximal level during slaughter. CK activity was more elevated after short transportation in younger horses, whereas initial activity of AST was higher in older horses. We estimated that intensified responses from acute phase, oxidative stress and muscle injury parameters indicated an inflammatory state.

Effect of leptin on thyroid-stimulating hormone secretion and nitric oxide release from pituitary cells of ewe lambs in vitro

Taking into account that the relationship between leptin and thyroid-stimulating hormone (TSH) secretion in ewe lambs is not clear, the objective of the present study was to estimate the effect of leptin on basal TSH secretion from ovine pituitary cells in vitro. Moreover, the influence of leptin on nitric oxide (NO) release and its role in the leptin-modulated secretion of TSH was studied. Pituitary cells were cultured in the McCoy 5A medium without hormones (the control), with 10⁻¹⁰-10⁻⁵ mol/L of leptin or with 10⁻¹⁰-10⁻⁵ mol/L of leptin and L-NAME (N(ω)-nitro-L-arginine methyl ester, 3 x 10⁻⁴ mol/L, the inhibitor of NO synthesis). The secretion of thyroid-stimulating hormone as well as concentration of nitrite (as an indicator of nitric oxide release) were analysed after 2-72 hours of experiment. The obtained results show that TSH secretion from ovine pituitary cells in vitro is dependent on leptin concentration: 10⁻¹⁰-10⁻⁶ mol/L of leptin causes an increase in TSH secretion, whereas the highest concentration of leptin (10⁻⁵ mol/L) suppresses thyroid-stimulating hormone release compared to the control. TSH secretion reaches the highest values under the influence of 10⁻⁸ mol/L of leptin. Moreover, leptin, depending on its dose and time of cell exposition, stimulates NO release from anterior pituitary cells of ewe lambs in vitro. The inhibition of NO synthesis with L-NAME annihilates the stimulating effect of leptin on thyroid-stimulating hormone secretion.

Leptin influences histidine dipeptides and nitric oxide release from anterior pituitary cells of sheep in vitro

Our previous results show that leptin, as well as nitric oxide (NO) and some antioxidants (histidine dipeptides - HDP) change the secretion of gonadotrophins from ovine adenohypophysis cells in vitro. NO and HDP are produced by pituitary and can modulate gonadotropin secretion by autocrine action. It is possible that these compounds mediate leptin influence on gonadotropin secretion. Therefore, the objective of the present study was to analyse leptin effect on NO and HDP (3-metyl-L-histidine, carnosine and anserine) release from ovine pituitary in vitro. Adenohypophysis cells were cultured in McCoy 5A medium with GnRH (4 x 10(-9) M) and 10(-10)-10(-5) M/l of leptin, respectively. Next, the media for analysis of NO (Griess method) and HDP (HPLC) were collected. Leptin in concentration of 10(-8)-10(-6) M/l caused a significant augmentation in NO in the culture medium, whereas in the dose of 10(-5) M/l reduced (P< or =0.05) NO release. The level of 3-metyl-L-histidine and anserine, but not carnosine, was significantly lower in the culture with 10(-8)-10(-7) M/l of leptin. Taking into account that 10(-8)-10(-7) M/l leptin stimulates LH and FSH secretion, as show in our previous study, it is possible that this effect in ewes is mediated by augmented release of NO and reduction of HDP level.

Leptin effect on nitric oxide and GnRH-induced FSH secretion from ovine pituitary cells in vitro

The secretion of gonadotrophins from anterior pituitary cells can be modulated by leptin and signals originating from the immune system, among others, by nitric oxide (NO). There are some studies that have demonstrated a role for leptin and NO in the regulation of FSH in rodents, however, no similar data are available in regards to ewes. Therefore, the objective of the present study was to analyse the leptin effect on GnRH-induced FSH secretion from the ovine anterior pituitary cells in vitro. Additionally, the influence of leptin on NO release and its role in the GnRH and leptin-modulated secretion of FSH from pituitary gland of ewes was investigated. The obtained results show that the influence of leptin on FSH secretion is biphasic. Leptin in concentration 10(-8) and 10(-7) M/l significantly enhances, whereas 10(-6) and 10(-5) M/l of leptin suppresses FSH secretion from the pituitary cells in comparison to the control. The secretion of FSH and NO release under the influence of leptin are in very high positive correlation (r=0.77). The inhibition of NO synthesis with L-NAME., instead, disables leptin from the stimulation of FSH secretion.

Fasting-induced changes in ovulation rate, plasma leptin, gonadotropins, GH, IGF-I and insulin concentrations during oestrus in ewes

The aim of this experiment was to study the changes in the hormonal status and ovulation rate (OR) evoked by starvation during the follicular phase of the oestrous cycle in ewes. To achieve this goal, 12 female crossbreed sheep were synchronized and then half of them were fasted from the 12th to the 16th day of the oestrous cycle. On the 16th day, analysis of hormones and insulin-like growth factor-I (IGF-I) were performed in 10-min intervals. Then, on the 6th day of the following oestrous cycle, the OR in all ewes was determined by laparoscopy. Fasting reduced significantly (P < 0.05) the OR in ewes (1.25 +/- 0.50) in comparison with control (1.75 +/- 0.50). The drop in the OR was coincident with a significant (P < 0.001) decrease in the plasma concentration and pulse amplitude of leptin (0.29 +/- 0.08 ng/ml versus control 0.53 +/- 0.14 ng/ml), the plasma level of luteinizing hormone (LH) (0.19 +/- 0.06 IU/l versus 0.25 +/- 0.09 IU/l in control; P < 0.05) and the mean frequency of LH pulses (2.0/h versus 2.5/h in control). Fasting resulted also in a significant (P < 0.05) decrease in the plasma concentration and pulse amplitude of follicle stimulating hormone (FSH) in comparison with the control. Simultaneously, a significant (P < 0.001) drop in the IGF-I concentration in the fasted ewes (4.78 +/- 0.91 ng/ml) was found in comparison with control (7.63 +/- 1.85 ng/ml). Also the level of insulin were significantly (P < 0.001) lower in the fasted (178.99 +/- 39.08 pM/l respectively) than in the control sheep (302.66 +/- 49.01 pM/l respectively). Meanwhile, a double increase in the growth hormone (GH) pulses frequency and an augmentation in its plasma concentrations as a result of starvation was found. The obtained results shows that the acute fasting exerts an inhibitory effect on the ovulation rate in ewes coincident with suppression in leptin, FSH and LH secretion and changes in signalization mediated by GH.

Assessment of neutrophil components as markers of lung injury in the course of bovine respiratory tract infections

To define the role of activated neutrophils in lung injury during bovine respiratory tract infections (BRTI) their in vitro function was investigated. As a means to achieve this goal the comparison of secretory action between neutrophils from the BRTI group and control was made on the basis of elastase, myeloperoxidase (MPO), alkaline phosphatase (ALK-P) release, and nitric oxide production. We noted that there is an interdependence between secretory response of neutrophils and clinical severity of BRTI. The release of elastase was greater in the BRTI group than in the control group (49.17+/-4.41 versus 46.43+/-4.95% of the total content). Neutrophils from infected heifers exhibited a significantly (p<0.05) higher value of MPO release than from healthy heifers and reached 39.23+/-10.18 versus 25.54+/-8.41% of the total content. ALK-P containing granules released significantly (p<0.001) more enzyme in the group with BRTI than in the control group (22.42+/-6.27 versus 13.74+/-2.01% of the total enzyme content). The level of nitrite accumulation rose in the culture of cells isolated from heifers with BRTI from 4+/-0.53 microM after 0.5h to 6.9+/-0.52 microM after 72 h. Our data suggest that during BRTI the increase of neutrophil secretory action results in augmentation of enzyme release including elastase, MPO and ALK-P, and the nitrite production. During an excessive secretory response of neutrophils all these factors contribute to lung injury and worsen the course of a disease and might be recognised as markers of lung injury. Moreover, such a destructive action of neutrophils must be taken into account during the introduction of new methods of BRTI treatment.

Changes in the Level of Endogenous Leptin, FSH, 17beta-Oestradiol and Metabolites during Lupin-induced Increase in Ovulation Rate in Ewes

The aim of the study was to determine the changes in the plasma concentration of leptin during lupin feeding-induced increase in the ovulation rate (OR) in ewes. Additionally, alterations in the plasma level of glycogenic amino acids and glucose (as the factors influencing leptin secretion) and the levels of follicle-stimulating hormone (FSH) and 17beta-oestradiol (E-2) (as the hormones regulated by leptin and engaged in recruitment, selection and development of ovulatory follicles) were analysed. Ninety-six female Polish Lowland Sheep were used. All ewes were cyclic and synchronized with PGF2alpha. The ewes were divided into two groups: control (n = 48), fed only with hay, and experimental (n = 48), received additionally lupin (Lupinus angustifolius) grain as a high-protein and a high-energy supplement. They were given lupin from the second to 13th day of the oestrous cycle at increasing doses (150-750 g/day per ewe). On the 11th day of cycle blood samples for analysis of hormones, amino acids and total glucose concentration, were collected from the jugular vein. OR was determined by laparoscopy of ovaries on the sixth day of the following oestrous cycle. Mean OR of ewes supplemented with lupin grain (1.687 +/- 0.463) was 30.67% higher than that of control (1.291 +/- 0.454). In spite of the unchanged body mass, a significant increase (P < or = 0.05) in mean concentration of plasma leptin in the experimental ewes [2.17 +/- 0.15 ng/ml human equivalent (HE)] was found in comparison with control (1.42 +/- 0.12 ng/ml HE). A significantly (P < or = 0.05) higher plasma FSH level in the ewes fed lupin (105.21 +/- 5.87 ng/ml) compared with those fed hay (67.88 +/- 6.03 ng/ml) was also found. However, plasma level of E-2 decreased after lupin feeding. Moreover, in the ewes fed lupin the plasma concentrations of glucose and nine glycogenic amino acids (Gly, Ala, Val, Met, Leu, Ile, Tyr, Phe and Arg) were increased. It can be concluded that lupin feeding exerts the stimulatory effect on the OR in Polish Lowland Sheep. The increase in OR is connected with significantly higher plasma leptin level and coincident with rise in FSH, glycogenic amino acids and glucose concentration. In contrast, the level of plasma E-2 was significantly decreased in lupin-fed ewes.

Relationships amongst liver bile salt clearance, bile secretion and infusion of lipids in calves

In order to study the influence of portal lipid loading on the extraction rate of bile salts by the liver, four cholecystectomized calves (mean body weight 103 kg) were fitted with permanent cannulae to the common bile duct, duodenum and portal vein. A venflon catheter was also set up in the jugular vein to collect blood for analysis of fatty acids (FA) and bile salts (PBS) in plasma. The experiments were divided into two parts. In the first part sodium taurocholate (TCHNa) was infused for at least 2 h at a rate of 25 mumol/min into the duodenum to stabilize the bile flow and bile salt output in bile and the concentration in plasma. In the second part, as well as TCHNa, Intralipid (Itlp) (infusible 10% of lipid compounds) was also infused into the portal vein. Itlp was infused for 40 min, starting at a rate of 3 ml/min at the beginning of the 3rd hour of TCHNa infusion followed by a rate of 6 ml/min at the beginning of the 4th hour of TCHNa infusion. During TCHNa infusion the plasma bile salt concentrations were in the range 15.69-20.21 mumol/l, similar to that of the pre-infusion period. Introduction of Itlp to the infusion of TCHNa resulted in a significant (P < 0.05) increase of PBS, about 2 times higher at an Itlp infusion rate of 3 ml/min, and 3 times higher (62.82 +/- 16.42 mumol/l) at 6 ml/min. Under Itlp infusion, all common plasma FA increased, but the largest increases were in levels of linolenic, palmitic and oleic acids. During TCHNa infusion, the bile flow and the content of bile salts in bile did not change. The infusion of TCHNa with Itlp at the rate of 6 ml/min caused a 2-fold decrease both of the bile flow and of the output of bile salts from 18.58 +/- 3.04 microliters/min/kg and from 0.58 +/- 0.07 mumol/min/kg observed at the beginning of both infusions to 9.51 +/- 2.95 microliters/min/kg and 0.28 +/- 0.05 mumol/min/kg, respectively, at the end of the collecting period. When only TCHNa was infused, almost all of it was secreted to the bile, while with the additional infusion of Itlp only about half of the infused TCHNa was secreted to the bile. These results indicate that the extraction rate of PBS by the liver is decreased by loading of the portal blood by lipids, allowing more bile salts to escape into the systemic circulation, and thus reducing bile production.