Effects of VIP and GRF on the release of growth hormone in perifused bovine adenohypophysis

The effects of vasoactive intestinal polypeptide (VIP) and growth hormone releasing factor (GRF:hpGRF(1–29)-NH₂) on the release of growth hormone (GH) from anterior pituitaries from cows were examined by using an in vitro superfusion system. The pituitaries were excised randomly from cycling cows, dissected to obtain medial portions, and minced to obtain cubes with approximate dimensions of 1.5mm on a side. For each perifusion setup, 5 pieces of pituitary tissues were chambered and flushed with modified KRB solution saturated with 95% O₂-5% CO₂ at 38C. Perifusion with media containing 10⁻⁶ and 10⁻⁷M VIP for 30 min induced a significant release of GH during the treatments (P<0.05). VIP (10⁻⁸M) increased GH levels significantly (P<0.05), but to a minor degree. Perifusion with the media containing 10⁻⁶, 10⁻⁷ and 10⁻⁸M GRF for 30 min markedly increased the GH concentration and the effects continued up to 90 min after termination of the perifusion of the peptide (P<0.05, P<0.01). The GH releasing effects of GRF could be seen at doses as low as 10⁻¹¹M GRF (P<0.05, P<0.01).

These findings indicate that the GH releasing effect of VIP is less potent that that of GRF in cows.     

Perforin expression can define CD8 positive lymphocyte subsets in pigs allowing phenotypic and functional analysis of natural killer, cytotoxic T, natural killer T and MHC un-restricted cytotoxic T-cells

In this study we have used the expression of perforin to characterize subsets of porcine cytotoxic lymphocytes. Perforin positive lymphocytes expressed both CD2 and CD8, most were small dense lymphocytes (SDL) and up to 90% were CD3 negative. However, the numbers of perforin positive T-cells increased with the age of the animal and their populations increased after specific antigen stimulation in vitro. The remaining perforin positive lymphocytes were large and granular and contained more CD3⁺CD5⁺CD6⁺ T-cells (−40%) of which a substantial proportion also co-expressed CD4. Perforin was expressed in subpopulations of both CD8 and CD8β lymphocytes, but was not expressed in γδ T-cells or monocyte/macrophages. The perforin positive CD3⁻ subset was phenotypically homogeneous and defined as CD5⁻CD6⁻CD8β⁻CD16⁺CD11b⁺. This population had NK activity and expressed mRNA for the NK receptor NKG2D, and adaptors DAP10 and DAP12. Perforin positive T-cells (CD3⁺) could be divided into at least three subsets. The first subset was CD4⁻CD5⁺CD6⁺CD11b⁻CD16⁻ most were small dense lymphocytes with cytotoxic T-cell activity but not all expressed CD8β. The second subset was mainly observed in the large granular lymphocytes. Their phenotype was CD4⁺CD5⁺CD6⁺CD8β⁺CD16⁻CD11b⁻ and also showed functional CTL activity. Thus not all of double positive T-cells are memory helper T-cells. The third subset did not express the T-cell co-receptor CD6, but up to half of them expressed another T-cell co-receptor CD5. The majority of this subset expressed CD11b and CD16, thus the third perforin positive T-cell subset was CD3⁺CD4⁻CD5⁺CD6⁻CD8β^±CD11b⁺CD16⁺, and possessed MHC-unrestricted cytotoxicity and LAK activity.     

Effects of a second mutant allele (V199I) at the PRKAG3 (RN) locus on carcass composition in pigs

The effect of a second mutant allele (V199I, here denoted rn*) at the PRKAG3 (RN) locus on carcass composition was determined in 334 pigs, entire males and females, from crosses between Swedish Hampshire (H) and Finnish Landrace (L) (H × LH; LH × H; LH × LH). Pigs were classified according to DNA test into the following PRKAG3 genotypes: RN⁻/RN⁻ (23%), RN⁻/rn⁺ (24%), RN⁻/rn* (33%), rn⁺/rn⁺ (8%), rn⁺/rn* (9%) and rn*/rn* (2%). The pigs were slaughtered at a commercial slaughterhouse and assessed 24 h postmortem. Right sides were fabricated into primary wholesale cuts, then further processed into defatted hams and loins, and a subset of hams (n = 122) was dissected into the five major individual muscles. The genotype frequencies for the subsample were RN⁻/RN⁻ (27%), RN⁻/rn⁺ (20%), RN⁻/rn* (35%), rn⁺/rn⁺ (9%), rn⁺/rn* (8%) and rn*/rn* (1%). Weights were recorded for meat and bone in ham and loin, fat in ham, back and shoulder and the individual dissected muscles. The genotype effect was significant (P < 0.05) for estimated lean meat content and the proportions of meat and bone and fat in ham and loin (of carcass weight). Also, the content of meat and bone in ham and loin, in proportion of whole ham and loin, respectively, differed significantly (P < 0.01) between genotypes. Estimated lean meat content was highest for RN⁻/RN⁻ (63.0%) and RN⁻/rn⁺ (63.1%) and lowest in the combined group rn*/⁻ (rn⁺/rn* and rn*/rn*, 61.7%); RN⁻/rn* (62.5%) and rn⁺/rn⁺(62.1%) were intermediate. The same results were found for meat and bone in ham and loin, as a proportion of whole ham and loin, respectively. RN⁻/RN⁻ and RN⁻/rn⁺ did not differ in any trait; however, they produced carcasses with the lowest proportions of fat within loin and the major wholesale cuts (ham, loin and shoulder). The carcass percentage of meat and bone in ham was higher in the three RN⁻/ genotypes (RN⁻/RN⁻, RN⁻/rn⁺ and RN⁻/rn*, P < 0.05) than in the rn*/⁻ group, whereas rn⁺/rn⁺ did not (P > 0.05) differ from any of the other genotypes. RN⁻/rn⁺ and RN⁻/rn* had higher (P < 0.05) proportion of meat and bone in loin compared to the rn*/⁻ group. We conclude that the second mutant allele found at the PRKAG3 (RN) locus, rn*, decreased the lean meat content compared with the two other alleles (RN⁻, rn⁺). The RN⁻/RN⁻ and RN⁻/rn⁺ genotypes were leanest, followed by RN⁻/rn* and rn⁺/rn⁺, and rn⁺/rn* and rn*/rn* were the fattest.     

The effect of pentaghrelin on amylase release from the rat and porcine dispersed pancreatic acinar cells in vitro

Ghrelin-28 was found to inhibit the pancreatic enzyme output in rats, although the effect of pentaghrelin has not been studied. The effect of ghrelin on pig exocrine pancreas remains largely unknown. The aim of the present study was: (1) to establish a model of porcine dispersed pancreatic acinar cells in vitro and compare it with an existing rat model, and (2) to investigate the effect of pentaghrelin on amylase release from the rat and pig pancreatic acini. The rat and porcine acinar cell preparations released amylase in response to cholecystokinin octapeptide (CCK-8) stimulation in a dose-related manner. Pentaghrelin hardly inhibited the amylase release in rat preparations (maximum inhibition with 10^− 9 M pentaghrelin). It stimulated amylase release in porcine preparations, however, no dose response was found in a range of doses between 10^− 10 and 10^− 7 M. Concluding, pentaghrelin may stimulate amylase release from porcine acinar cells through as yet unknown mechanisms.     

Effect of a nonsteroidal aromatase inhibitor on in vitro and in vivo secretion of estradiol and on the estrous cycle in ewes.

Three experiments were performed to study effects of decreased concentrations of estradiol-17β (E₂) on lifespan and function of ensuing ovine corpora lutea (CL). In experiment 1, 52 follicles were collected from 10 ewes and placed into individual culture with 0 or .01 μCi ³H-androstenedione (10 ng; ³H-A) and 0, 10⁻¹¹, 10⁻⁹, 10⁻⁷, or 10⁻⁵ M of a nonsteroidal aromatase inhibitor, CGS16949A (CGS). Concentrations of E₂ secreted into the medium, and synthesis of estrogens as estimated by formation of ³H-water from ³H-A were decreased by 10⁻⁵ and 10⁻⁷ (P<.01), but not 10⁻⁹ or 10⁻¹¹ M CGS. In experiment 2, luteolysis was induced in 24 ewes by injection of PGF₂ on days 5 to 10 of the estrous cycle (0 hr). Ewes received 0, 0.5, 1.0, 2.0 or 4.0 mg CGS per kg BW i.v. at −12, 0, 12 and 24 hr, and an ovulatory dose of hCG at 36 hr. Jugular (P<.001) and vena caval (P<.001) concentrations of E₂ were decreased by CGS at all doses tested for 8 to 10 hr, but had returned to levels similar to control ewes by the time of the next injection. Concentrations of E₂ around the time of the LH surge were similar in control and treated ewes. During the subsequent luteal phase, concentrations of progesterone (P₄) were similar in control and treated ewes. Thus, transient decreases in E₂ during the follicular phase were not deleterious to the subsequent luteal phase. In experiment 3, luteolysis was induced in 18 ewes by injection of PGF₂ on days 6 or 7 (0 hr) of the estrous cycle. Ewes received 0 or 1 mg CGS per kg BW i.v. every 8 hr from 0 to 40 hr. Ovulation was induced with hCG at 36 hr. CGS reduced jugular (P<.001) and vena caval (P<.001) concentrations of E₂, prevented an endogenous surge of LH (P<.05) and increased (P<.001) concentrations of FSH. All ewes had ovulated a marked follicle by 72 hr, but onset of the luteal phase, as assessed by concentrations of P₄, was delayed (P<.01) in ewes receiving CGS. Delayed luteal phases were not solely attributable to the presence of new CL or to luteinization of follicular cysts. When data were aligned according to the day ewes were observed in estrus, profiles of P₄ did not differ with treatment. Therefore, normal luteal function ensued following estrus whether or not ewes re-ovulated. In conclusion, decreased secretion of E₂ by the preovulatory follicle was not involved in the ontogeny of CL of short lifespan or subnormal function. Instead, adequate production of E₂ or precisely timed E₂ secretion may be required during follicular development for subsequent functional luteinization.     

CpG-ODN enhances mammary gland defense during mastitis induced by Escherichia coli infection in goats

Seven healthy native goats in early lactation, weighing 30–40 kg, were used in this study. The right mammary gland of the seven does were infused with CpG-ODN at a dosage of 100 μg kg⁻¹ body weight on the day 5 postpartum (PP). The left glands were used as controls and infused with sterile phosphate-buffered saline (PBS). On day 8 PP, the same dosage of CpG-ODN or PBS was again infused. On day 9 PP, the mammary glands (both right and left) of the seven does were infused with 6 × 10⁶ colony-forming units (CFU) Escherichia coli and, at 0, 8, 16, 24, 48 and 72 h postinfection (PI), milk samples were collected from all glands. Goats were euthanized at 72 h PI and the mammary tissue harvested. Infusion with 6 × 10⁶ CFU ml⁻¹ E. coli induced acute mastitis. Histopathological evaluations showed that polymorphonuclear neutrophils (PMNs) were still present in alveoli at 72 h PI, but PMNs in the CpG-ODN-treated glands has disappeared. Bacteria counts in milk peaked at 16 h PI and CpG-ODN induced a significant decrease in viable bacteria from 16 h PI until the end of the experiment. This study showed that CpG-ODN promoted the expression of its specific receptor (TLR-9 mRNA) in mammary tissue, stimulated IL-6 production, reduced bacteria counts in milk, attenuated the impact of inflammation mediators on cells and significantly shortened the inflammation course. These results suggest that the CpG-ODN improved mammary gland defense and, thereby, had a beneficial effects against mastitis caused by E. coli infection in goats.     

The C bicarbonate dilution technique to determine energy expenditure in young bulls validated by indirect calorimetry

We explored the applicability of the ¹³C bicarbonate dilution technique for determination of energy expenditure (EE) in young bulls in comparison to whole body indirect calorimetry (IC). Twelve bulls of a F2 German Holstein x Charolais cross (4.5 months, 332 ± 16 kg BM) received a diet providing 1000 kJ ME d^− 1 kg BM^− 0.75 and 4.3 g crude protein d^− 1 kg BM^− 0.75. Bulls were housed in respiration chambers and received an intravenous bolus of NaH¹³CO₃ (A: 3 μmol kg BM^− 1 (n = 2), B: 7 μmol kg BM^− 1 (n = 4), C: 17.5 μmol kg BM^− 1 (n = 6), 99 at.% ¹³C) into the jugular vein to measure EE. Simultaneously, EE was determined by IC. After the ¹³C administration blood samples and breath gas were collected from the animals in the respiration chamber during a 24-h period (7.00–7.00 h). The recovery of ¹³C in breath CO₂ (% of ¹³C dose) was irrespective of NaH¹³CO₃ dose (A: 69.7 ± 2.7%, B: 70.5 ± 4.5%, C: 75.0 ± 4.9%; P > 0.05). Only small amounts of ¹³C were excreted in urine (3.4 ± 2.6%) and feces (2.0 ± 1.3%). The EE determined by the ¹³C bicarbonate method using breath and blood ¹³C recovery rates as correction factors was not different from that measured by IC (816 ± 81 [blood] or 827 ± 101 [breath] vs. 820 ± 90 kJ d^− 1 kg BM^− 0.75). Bland–Altman analysis showed a 95% confidence interval for EE of ± 99 and ± 109 kJ d^− 1 kg BM^− 0.75 based on blood and breath ¹³C recovery, respectively. In conclusion, the ¹³C bicarbonate dilution method is appropriate to obtain reliable estimates of EE in young bulls using blood CO₂ or breath CO₂ under standardized experimental conditions, i.e. in the fasting state.     

Effects of pituitary adenylate cyclase-activating polypeptide (PACAP), prostaglandin E2 (PGE2) and growth hormone releasing factor (GRF) on the release of growth hormone from cultured bovine anterior pituitary cells in vitro

The effect of pituitary adenylate cyclase-activating polypeptide (PACAP) on growth hormone (GH) release was compared with that of prostaglandin E₂ (PGE₂) and growth hormone releasing factor (GRF) from cultured bovine anterior pituitary cells in vitro. Both PACAP and PGE₂ stimulated GH release at concentrations as low as 10⁻⁹ and 10⁻⁸ M, respectively, (P<0.01). However, GRF released GH at a concentration as low as 10⁻¹³ M (P<0.01). Percent increases of GH compared with controls were not significantly different among GRF, PACAP, and PGE₂ at 10⁻⁷ M; however, the increases of GH by the 10⁻⁸ M GRF, PACAP and PGE₂ were 196, 118, and 27%, respectively, (P<0.01), and 124, 65, and 1% in the 10⁻⁹ M media, respectively, (P<0.01). When GRF and somatostatin (SS) were added together, the GH releasing effect of GRF was blunted (P<0.01). Similar bluntness were observed in PACAP and PGE₂, when SS was added. The stimulatory effects of GRF and PGE₂ together were similar to that by either GRF or PGE₂ alone. When GRF and PACAP were added together, the GH released by both secretagogues was greater than that by PACAP alone (P<0.01); however, a synergistic effect was not clear when compared with GRF alone.

These findings suggest that PACAP and PGE₂ may modulate the release of GH in cattle.     

Production of interleukin-2 mRNA by bovine lymph node lymphocytes in response to concanavalin A, 12-O-tetradecanoylphorbol-13-acetate, and ionomycin

Interleukin-2 (IL-2) is a lymphokine which, upon binding to its receptor, leads to the proliferation and differentiation of T-cells (helper, suppressor, and cytotoxic) and B-cells. While human and murine IL-2 have been extensively studied, less is known about bovine IL-2. In order to understand the induction of bovine IL-2 at the molecular level, we have examined IL-2 mRNA induction. The dose-responses and time courses of the production of IL-2 mRNA in response to Concanavalin A (ConA), 12-O-tetradecanoylphorbol-13-acetate (TPA), and ionomycin in lymph node lymphocytes (LNC) were determined. We found that high levels of IL-2 mRNA were produced in response to 1 μg ml⁻¹ ConA plus 10⁻⁸ M TPA, but that even higher levels were produced in response to 1 μM ionomycin plus 10⁻⁸ M TPA. We also found that LNC stimulated with ConA displayed two phases of IL-2 mRNA production, one occurring approximately 2–4 h after stimulation and one occurring approximately 10 h after stimulation. However, in the presence of ConA plus TPA or ionomycin plus TPA the response was monophasic. IL-2 mRNA was detected within 2 h of addition of ConA plus TPA (the earliest time examined), reached maximum levels within 6 h, and declined to low levels after 12 h. IL-2 mRNA from LNC incubated with ionomycin plus TPA appeared within 2 h, and reached maximum levels at about 9 h. In contrast to the decrease seen after 12 h with ConA plus TPA, IL-2 mRNA from these cells remained high for 18 h and declined to low levels after 24 h.     

Quantitative risk assessment of human listeriosis from consumption of soft cheese made from raw milk

Microbial hazards have been identified in soft cheese made from raw milk. Quantification of the resulting risk for public health was attempted within the frame of the Codex Alimentarius Commission, 1995 approach to quantitative risk assessment, using Monte Carlo simulation software. Quantitative data could only be found for Listeria monocytogenes. The complete process of cheese making was modeled, from milking to consumption. Using data published on the different sources of milk contamination (environment and mastitis) and bacterial growth, distributions were assumed for parameters of the model. Equations of Farber, J.M., Ross, W.H., Harwing, J. (1996) for general and at-risk populations were used to link the ingested dose of L. monocytogenes to the occurrence of listeriosis. The probability of milk contamination was estimated to be 67% with concentration ranging from 0 to 33 CFU ml⁻¹. The percentage of cheese with a predicted concentration of L. monocytogenes greater than 100 CFU g⁻¹ was low (1.4%). The probability of consuming a contaminated cheese serving was 65.3%. Individual annual cumulative risk of listeriosis, in a population each consuming 50 servings of 31 g, ranged from 1.97 × 10⁻⁹ to 6.4 × 10⁻⁸ in a low-risk sub-population and 1.04 10⁻⁶ to 7.19 10⁻⁵ in a high-risk sub-population. The average number of expected cases of listeriosis per year was 57 for a high-risk sub-population and one for a low-risk healthy sub-population. When the frequency of environmental milk contamination was reduced in the model and L. monocytogenes mastitis was eliminated, the expected incidence of listeriosis decreased substantially; the average number of expected cases was reduced by a factor of 5. Thus the usefulness of simulation to demonstrate the efficiency of various management options could be demonstrated, even if results should be interpreted with care (as many assumptions had to be made on data and their distributions).     

Impact of controlled fermentation and steeping of high moisture corn on its nutritional value for pigs

High moisture corn (HMC) can undergo fermentation during storage that may improve its nutritional value for pigs. Stored HMC used in this study contained (n = 4) 75% dry matter (DM), and, on a DM basis, 63.8% starch, 0.5% mono and disaccharides, 9.9% protein, 19 mM acetic acid, 18 mM lactic acid (LA), 1.25 × 10⁷ cfu g^− 1 of LA producing bacteria, 2.88 g kg^− 1 total phosphorus (P), and 1.26 g kg^− 1 soluble P. The soluble P content was higher than in freshly harvested HMC (0.27 g kg^− 1 DM) and indicates P release during storage. Studies were aimed at altering the nutritional value of stored HMC by controlled fermentation or steeping. Changes in LA content were not affected (P > 0.05) by addition of exogenous Lactobacillus and Bacillus bacteria. Steeping of HMC with phytase (Ronozyme) was examined at four inclusion levels (0, 500, 750, 1000 FTU kg^− 1) and at either 21 °C or 37 °C. At 37 °C added phytase released virtually all phytate P within 6 h irrespective of the level (levels increased by 1.44 g P kg^− 1 DM); at 21 °C, the increase was maximized at 1.2 g P kg^− 1 DM after 24 h. The feeding value of HMC for pigs can be altered by steeping with exogenous phytase and does not appear to require microbial inoculants.     

Prolactin signaling in porcine adrenocortical cells: involvement of protein kinases

Prolactin (PRL) was found to have a stimulatory effect on adrenal steroidogenesis in vivo and in vitro in several species including pigs. PRL signal transduction pathways, however, in adrenocortical cells are poorly recognized. Therefore, the goal of this paper is to ascertain the involvement of protein kinase C (PKC) and tyrosine kinases in PRL signaling in porcine adrenal cortex. Adrenals were harvested from locally slaughtered mature gilts. Cortical cells were dispersed by sequential treatment with collagenase. The cells were seeded into 24-well culture plates at a density of 3×10⁵/mL. Cells were incubated with or without PRL (500 ng/mL), ACTH (5 nM—a positive control), tyrosine kinase inhibitor—genistein (1; 2.5 or 5 μM), PKC inhibitor—sphingosine (20–1000 nM) and PKC activators—diacylglycerol (DiC8; 10–100 μM) and phorbol ester (PMA; 1–1000 nM). All incubations were performed for 8 h (95% air and 5% CO₂, 37°C). PRL and ACTH (P<0.05) increased cortisol and androstenedione (A₄) secretion. DiC8 and PMA mimicked the stimulatory effect of PRL. Sphingosine (P<0.05) suppressed basal and PRL-stimulated steroid secretion. Genistein inhibited (P<0.05) PRL-stimulated cortisol secretion and enhanced (P<0.05) basal and PRL-stimulated A₄ secretion. Moreover, PKC activation was assessed by measuring the specific association of [³H]phorbol dibutyrate ([³H]PDBu) with adrenocortical cells after treatment with PRL or ionomycin (a positive control). PRL (within 2–3 min) and ionomycin (within 2–5 min) increased (P<0.05) specific binding of [³H]PDBu to the porcine adrenocortical cells. In addition, PRL did not augment the cortisol and A₄ secretion by PKC-deficient adrenocortical cells. In conclusion, presented results support the hypothesis that PKC and tyrosine kinases are involved in PRL signaling in adrenocortical cells in pigs. Moreover, activation of PKC is associated with the increased secretion of cortisol and A₄.     

Studies on the pathogenesis of bovine ephemeral fever in experimental cattle III. Virological and biochemical data

In an attempt to define the nature of the response of cattle to ephemeral fever infection, a number of indicators of inflammation were monitored during clinical disease. The total Ca, Zn, Fe, Cu, glucose and phosphate in plasma, together with blood ammonia, were assayed relative to changes in the rectal temperature. Ca_T levels fluctuated markedly and hypocalcaemia occurred in 4 of 8 cattle. Plasma Zn and Fe values fell while plasma Cu levels rose markedly in all cattle. Mean levels of serum NH₃ of 20–30 μmol 1⁻¹ rose to a peak value of 56 μmoll⁻¹. Plasma glucose levels rose to a peak of 4.6 ± 0.5 mMl⁻¹ and the plasma phosphate levels fell from 2.4 ± 0.1 mMl⁻¹ to 1.17 ± 0.2 mMl⁻¹ during fever. Values of pCO₂ fell from a mean of 46.9 ± 3.6 mmHg to 36.4 ± 3.1 mmHg and coincided with a rise in pH. Virus was isolated 73 h (± 23) after inoculation and persisted until 130 h (± 21). The common role of these parameters in generalised inflammation and ephemeral fever is discussed.     

Genetic correlations between osseous fragments in fetlock and hock joints, deforming arthropathy in hock joints and pathologic changes in the navicular bones of Warmblood riding horses

The results of a standardized radiological examination of 5231 Hanoverian Warmblood horses were used to investigate heritability of and genetic correlations between prevalent radiographic findings in the equine limbs. Radiographic findings were categorized by joint location and type of visible alterations and analyzed as all-or-none traits. Heritabilities and correlations were estimated multivariately for most prevalent radiographic findings in equine limbs using Residual Maximum Likelihood (REML) and Gibbs Sampling (GS). Linear animal models and linear sire models were used for REML; sire threshold models were used for GS analyses. Heritabilities and residual correlations from linear model analyses were transformed from observed scale to underlying liability scale. Osseous fragments were seen in fetlock joints (OFF) of 23.5% and in hock joints (OFH) of 9.2% of investigated horses. Deforming arthropathy in hock joints (DAH) was diagnosed in 12.0% and pathologic changes in navicular bones (PCN) in 25.8% of investigated horses. Heritabilities differed little between analyses with animal and sire models and with REML and GS. Ranges of heritability estimates were h² = 0.16–0.44 with REML and h² = 0.07–0.43 with GS. Genetic correlation estimates were larger in GS than in REML analyses. Additive genetic correlation between OFF and DAH was positive (r_g = 0.25 to 0.77). Negative additive genetic correlations were determined between OFF and OFH (r_g = − 0.17 to − 0.82), between OFH and DAH (r_g = − 0.14 to − 0.81), and between OFH and PCN (r_g = − 0.19 to − 0.26). No relevant additive genetic correlations were estimated between PCN and OFF, and between PCN and DAH. The results of the present study indicate that the prevalences of common radiographic findings in the limbs of young riding horses are relevantly influenced by genetics and probably caused by different genes. Genetic correlations between radiological health traits therefore deserve closer attention in horse breeding. The quantitatively most important radiographic findings should be concurrently considered as individual traits in order to provide for general improvement of radiological health of the limbs of young Warmblood riding horses.     

Modulation of growth hormone-releasing factor-induced release of growth hormone from bovine pituitary cells

Growth hormone (GH)-releasing factor (GRF) at concentrations of 10−¹² through 10−⁷M for 6 hr linearly increased GH release (b₁ = 10.4 ± .3) from bovine anterior pituitary cells in culture. Maximum release of GH (262% above controls) occurred at 10−⁷M GRF. In contrast, GH release-inhibiting factor (SRIF) at 10−¹² through 10−⁵M had no effect on basal concentrations of GH. In a second experiment, as the proportion of SRIF relative to GRF increased. SRIF suppression of GRF-induced GH release from anterior pituitary cells increased. In a third experiment, anterior pituitary cells cultured in media containing fetal calf serum (FCS) were treated with cortisol (0 or 10 ng/ml media) for 24 hr before exposure to 10−¹³ through 10−⁷M GRF. GRF linearly increased GH secretion (b₁ = 7.4 ± .3) and cortisol augmented this response (b₁ = 10.5 ± .6). However, when cells were cultured in media containing dextran-charcoal treated FCS, cortisol did not alter GRF-induced GH release. Our results demonstrate that GH response of bovine anterior pituitary cells to GRF was modulated negatively by SRIF. However, augmentation of GRF-induced GH release by cortisol was evident only when cells were cultured in media supplemented with untreated FCS.     

Invasion and spread of single glycoprotein deleted mutants of Aujeszky''s disease virus (ADV) in the trigeminal nervous pathway of pigs after intranasal inoculation

The purpose of the study was to evaluate the role which non-essential envelope glycoproteins play in the neuroinvasion and neural spread of ADV. The invasion and spread in the trigeminal nervous pathway with the Ka strain of ADV and its single deletion mutants Ka gI⁻, Ka gp63⁻ and Ka gIII⁻ were examined after intranasal inoculation in neonatal pigs by virus isolation and immunocytochemistry. Evaluation was performed in the nasal mucosa, trigeminal ganglion (1st neuronal level), pons-medulla (2nd neuronal level) and thalamus-cerebellum (3rd neuronal level). The Ka gIII⁻ mutant invaded up to the 3rd neuronal level of the trigeminal pathway and spread in a similar way to the parental Ka strain. The Ka gp63⁻ mutant invaded up to the 3rd neuronal level but the spread of this mutant was impaired at all the neuronal levels. The Ka gI⁻ mutant was least neuroinvasive and reached only up to the 2nd neuronal level. The results showed that glycoproteins gI and gp63 play a role in the invasion and spread of ADV in the nervous system. However, the gI glycoprotein appears to be the most important for neuroinvasion and neural spread of ADV in pigs. Therefore, gI deleted vaccines may be considered to be safer with respect to the neuroinvasion than vaccines carrying single deletions of other non-essential envelope glycoproteins.     

Estrogenic and antioxidant effects of a phytoestrogen daidzein on ovarian germ cells in embryonic chickens

The estrogenic and antioxidant effects of the phytoestrogen daidzein (DAI) on germ cell proliferation were evaluated by a chicken ovarian germ-somatic cell coculture model. Ovarian cells were dispersed from 18-day-old embryos, cultured in serum-free McCoy's 5A medium and challenged with DAI alone or in combinations with estrogen receptor antagonist tamoxifen for 48 h. The number of germ cells was counted and the proliferating cells were identified by immunocytochemistry of proliferating cell nuclear antigen (PCNA). The labeling index (LI) was determined for germ cells. Results showed that DAI significantly increased the number of germ cells (P<0.05) and this stimulating effect was inhibited by tamoxifen in a dose-dependent manner. Furthermore, PCNA-LI of germ cells displayed similar changes with the number of germ cells. To estimate the antioxidant action of DAI, ovarian cells were exposed to the reactive oxygen species (ROS)-producing system hypoxanthine/xanthine oxidase (HX/XO). The changes of superoxide dismutase (SOD) activity and glutathione (GSH) level were measured for estimation of the antioxidant status. Ovarian cells were severely damaged by free radicals and this deteriorating effect could be prevented by DAI. Moreover, HX/XO-induced decrease in SOD activity and GSH level was restored by DAI (P<0.05). These results indicated that DAI promoted proliferation of cultured ovarian germ cells by estrogenic action and attenuated ROS-induced toxicity by antioxidant action in embryonic chickens.     

Genetic parameters and evaluation of the Tunisian dairy cattle population for milk yield by Bayesian and BLUP analyses

A Markov Chain Monte Carlo Bayesian method and BLUP analyses were used on Tunisian dairy cattle data. Data included 92,106 lactation records collected on 37,536 animals over 19 freshening years, from 1983 to 2001. Each record was partitioned into the fixed effects of herd-year, month of calving, and age-parity, a permanent environmental effect, an additive genetic effect, and a residual effect.

Posterior conditional distributions were determined for variance components and model effects. Solutions (BLUE) and posterior means for levels of herd-year, month of calving, and age-parity showed similar patterns. Posterior means of heritability and repeatability were 0.17 ± 18 × 10^− 5 and 0.39 ± 8 × 10^− 5, respectively. Posterior means of bull's breeding values were compared to bull's BLUP solutions. BLUP solutions were obtained using 0.17 and 0.39, estimated from the data, and 0.25 and 0.40 estimates for heritability and repeatability, respectively. Rank correlations between bull's posterior means and BLUP breeding values were 0.998 and 0.994 using genetic parameters estimated from the data and from the literature, respectively. This correlation coefficient was 0.995 between bull's BLUP solutions using either of the two sets of genetic parameters.     

Urinary excretion of glucocorticoids in the diagnosis of hyperadrenocorticism in cats

In dogs and humans, the measurement of urinary corticoid excretion has become a standard screening test for the diagnosis of hyperadrenocorticism. Mainly because the urinary excretion of cortisol was considered to be very low in cats, its measurement was not used in the diagnosis of hyperadrenocorticism in this species. We therefore studied the urinary excretion of [³H]cortisol and measured the corticoid/creatinine (C/C) ratio in healthy cats and in cats with hyperadrenocorticism in order to evaluate the applicability of this measurement in the diagnosis of feline hyperadrenocorticism. The median urinary excretion of intravenously administered [³H]cortisol was 1.85% (measured as excreted ³H; range, 1.56 to 1.99; n = 4). High-performance liquid chromatography analysis showed a small peak of cortisol and a large peak consisting primarily of conjugates of cortisol and/or its metabolites. The 2.5 and 97.5 percentiles of the urinary C/C ratio in healthy cats were 2 × 10⁻⁶ to 36 × 10⁻⁶ (n = 42). The C/C ratio was significantly higher in six cats with pituitary-dependent hyperadrenocorticism (median, 122 × 10⁻⁶; range 51 × 10⁻⁶; to 272 × 10⁻⁶). The administration of a high dose of dexamethasone (0.1 mg/kg thrice daily per os) led to marked suppression of the C/C ratio in healthy cats (median suppression of the average of the C/C ratio of the first two consecutive days was 92%; range, 74 to 96%; (n = 12), as well as in five cats with pituitary-dependent hyperadrenocorticism. Our results demonstrate that despite the low urinary excretion of injected [³H]cortisol, urinary corticoid concentrations in cats can be measured by radioimmunoassay and that the urinary C/C ratio is a sensitive test in the diagnosis of hyperadrenocorticism in the cat.     

Salmonella enterica level in French pig farms effluents: Experimental and field data

The study aimed to (1) validate the mini-MSRV-MPN method to quantify Salmonella enterica in pig slurry, (2) estimate the effect and interaction on temperature, time and initial Salmonella load on the survival of the 2 strains of Salmonella typhimurium (PF 1690 and DT104 100/706/037) during slurry storage and (3) identify Salmonella contaminated finishing pig batches and assess the level of contamination of their slurry. The mini-MSRV-MPN method was compared to direct isolations on brilliant green agar supplemented with rifampicin to quantify Salmonella in pig slurry. Doelhert uniform shell design was used to study the effect of different parameters on the survival of the 2 strains of Salmonella in pig slurry. Environmental samples of faecal material and a sample of the slurry of 50 batches of finishing pigs were analysed by bacteriological classical method to identify Salmonella. Quantification was performed on pools of faeces and in slurry using the mini-MSRV-MPN technique. This method proved to be suited to quantify Salmonella in pig slurry. Temperature, time of slurry storage and their interaction influenced Salmonella decrease. 12 batches of pigs tested Salmonella positive. Quantification was possible in 5 batches of faecal samples (2.4–350 MPN g^− 1 of Salmonella). Quantification was achieved in 2 out of 6 positive samples of slurry (1.6 and 110 MPN mL^− 1 of Salmonella).