Hypocortisolism in the South African angora goat: the role of 3betaHSD

South African Angora goats are susceptible to cold stress, due to their inability to produce sufficient levels of cortisol. During adrenal steroidogenesis the production of cortisol relies on the activity of two key enzymes, namely cytochrome P450 17alpha-hydroxylase and 3beta-hydroxysteroid dehydrogenase. Cytochrome P450 17alpha-hydroxylase has previously been identified as a factor contributing to hypocortisolism in the South African Angora goat. In this comparative study, the catalytic activity of Angora and ovine 3beta-hydroxysteroid dehydrogenase, which differ by five amino acid residues, was characterized. The conversion of 17-hydroxypregnenolone and dehydroepiandosterone to their corresponding products, 17-hydroxyprogesterone and androstenedione, by the two enzymes differed significantly. The enzymes were subsequently co-expressed with Angora P450 17alpha-hydroxylase. Major differences were observed in pregnenolone metabolism with a significant reduction in the formation of the cortisol precursor, 17-hydroxyprogesterone, by cells expressing Angora 3beta-hydroxysteroid dehydrogenase, implicating 3beta-hydroxysteroid dehydrogenase as an additional factor contributing to hypocortisolism in the South African Angora goat.

Pathogenic effects of the coccidium Eimeria ninakohlyakimovae in goats

Twenty-four coccidia-free goats were reared artificially in indoor cages and allocated to 6 groups of 4 animals each. At 20 days of age, goats in groups 1-3 received 10(4),10(5) and 10(6) sporulated oocysts of Eimeria ninakohlyakimovae per goat, respectively, each as a single dose. Goats in group 4 received daily doses increasing over a 3-week period, starting with 100/day for the first week, followed by 1000, and 10,000/day in weeks 2, 3, respectively. Goats in group 5 received 10(4) oocysts following a challenge dose of 10(6) oocysts on day 32. Goats in group 6 were kept as uninoculated controls. Infected animals showed diarrhoea and weight loss. Goats in group 4 showed longer periods of diarrhoea and patency than other infected goats. Goats in group 5 showed the same severe clinical signs as those in group 3 but produced very low oocyst output after a challenge dose. The diarrhoea was associated with a reduction in alkaline phosphatase activity and increases in packed cell volume and haemoglobin. No significant differences were found in serum aspartate aminotransferase, alanine aminotransferase, total protein, albumin, globulin, Na+, K+,Cl- between groups during 48 days after inoculation. There were no serum enzyme indications of damage to the liver. Histological examination performed 100 days after inoculation revealed that inoculated goats had mild subacute to chronic proliferative enteritis in the lower small intestine and the large intestine, and the mesenteric lymph nodes, gallbladders and livers also showed slight histological lesions. The results showed that E. ninakohlyakimovae was highly pathogenic.

Serological changes in goats experimentally infected with Fasciola gigantica in Buea sub-division of S.W.P. Cameroon

Based on the recent increase in the rearing of West African Dwarf (WAD) goats in this environment, a study of biochemical parameters was carried out in healthy and infected goats to obtain baseline data for monitoring the health and productive indices in breeding programmes for the goats. The results revealed variations in some of the parameters studied. The serum minerals potassium, chlorine and bicarbonate did not show any significant differences (P>0.05) between the infected and control groups of goats, but there was a significant difference (P<0.0001) in sodium, calcium and urea levels. For serum lipids cholesterol and triglyceride, there were significant (P<0.0001) differences between the infected and control group. This goes same for serum proteins, albumin and total proteins. However, serum enzymes, serum glutamic oxaloacetic transaminase (SGOT) and gamma glutamyl transferase (GGT) were not significantly different (P>0.05) between the infected and control groups. There was a significant difference (P<0.0001) in alkaline phosphatase (ALP) and serum glutamic pyruvic transaminase (SGPT) between the infected and control groups.

Immunohistochemical study of constitutive neuronal and inducible nitric oxide synthase in the central nervous system of goat with natural listeriosis

The expression of both constitutive and inducible forms of nitric oxide synthase (NOS) was investigated by immunohistochemical staining of formalin-fixed paraffin-embedded sections in normal and Listeria monocytogenes-infected brains of goats. In normal control goats, a small number of neurons showed immunoreactivity of both iNOS and nNOS, and the number of iNOS-positive neurons was higher than the number of nNOS-positive neurons. In natural listeriosis, listeria antigens were easily immunostained in the inflammatory cells of microabscesses. In this lesion, the immunoreactivity of iNOS in neurons was more intense than the control, but nNOS was not. In microabscesses, nNOS was weakly visualized in macrophages and neutrophils, while iNOS was expressed in macrophages, but not in neutrophils. These findings suggest that normal caprine brain cells, including neurons, constitutively express iNOS and nNOS, and the expressions of these molecules is increased in Listeria monocytogenes infections. Furthermore, inflammatory cells, including macrophages, expressing both nNOS and iNOS may play important roles in the pathogenesis of bacterial meningoencephalitis in goat.

Inducible nitric oxide synthase is expressed in joints of goats in the late stage of infection with caprine arthritis encephalitis virus

We have studied the expression of the inducible form of nitric oxide synthase (iNOS) in joints of goats infected with the caprine arthritis encephalitis virus (CAEV). Nitric oxide generated by iNOS is thought to play an important role in the pathogenesis of various types of arthritis, especially rheumatoid arthritis (RA) in humans. Surprisingly, iNOS immunoreactivity was found only in joints of long-term infected goats with severe clinical arthritis, whereas-despite the presence of high numbers of inflammatory cells in the synovial tissue-no iNOS immunoreactivity was detected in mildly arthritic and in short-term experimentally infected goats. Most iNOS-positive cells expressed neither MHC class II nor CD68, which suggests that they were fibroblast-like synoviocytes. In situ hybridization studies showed that there was no correlation between iNOS immunoreactivity and detectable virus expression in the joint. In addition, infection of macrophages in vitro-the major host cells of CAEV in vivo-did not lead to increased iNOS mRNA expression. In response to stimulation, similar levels of iNOS expression were observed in infected and in uninfected macrophages. These findings suggest that the expression of iNOS is a feature of late-stage chronic arthritis and is not involved in the development of the inflammatory lesions. Both the lack of co-localization of iNOS protein and viral transcripts in the joint and the finding that CAEV does not stimulate the expression of iNOS in vitro further suggest that iNOS is not directly induced by the virus or the anti-viral immune response in the joint, that it may well, however, be involved in tissue remodelling or scar formation.

Studies on experimental chlamydial mastitis in goat histoenzymology

Two strains of Chlamydia psittaci (one isolated from aborted goat foetus and the other from brain of a buffalo calf that had died of meningoencephalitis) were injected intracisternally into six goats to produce experimental mastitis. Cryostat sections of 7-8 microns thickness, obtained from udder, teat, liver and kidney of infected and control animals were incubated for histoenzymic demonstration of alkaline-(AKPase), acid-(ACPase) and adenosine-tri-(ATPase) phosphatases; lactate-(LDH) and succinate-(SDH) dehydrogenases and for reduced nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-D). Results demonstrated that AKPase and NADPH-D declined while ACPase accumulated in acinar cells of udder while both NADPH-D and ACPase decreased in teat sinus epithelium. Hepatic canaliculi in perilobular areas of liver lobules registered complete absence of AKPase and ATPase. Hepatocytes and renal tubules accumulated LDH, SDH and NADPH-D. The interstitial connective tissue of udder and kidney presented higher levels of AKPase. Comparison of results with biochemical alterations in the level of these enzymes revealed striking discrepancies which seem to arise because of failure of biochemical procedures to discriminate between functional cells of tissue and inflammatory cells. The functional significance of histoenzymic alterations has been discussed.

Effect of caprine arthritis-encephalitis virus infection on milk cell count and N-acetyl-beta-glucosaminidase activity in dairy goats

Bacteriology, somatic cell counts (SCC) and N-acetyl-beta-glucosaminidase (NAGase) activity determinations were conducted on milk samples collected from does in three dairy herds with caprine arthritis-encephalitis virus (CAEV) infection. In two herds, CAEV-infected does were more likely to have a subclinical bacterial infection of the udder than CAEV-free does (P < 0.05). Does with CAEV but no bacterial udder infection had significantly greater mean SCC and NAGase activity than CAEV-free does without udder infection (P < 0.01). In two herds, changes in milk SCC and NAGase associated with CAEV infection were similar to those produced by coagulase-negative staphylococcal infections. The findings confirm that indirect indicators of bacterial mastitis infection may have reduced specificity in dairy goat herds with CAEV.

A gelatin test to detect activity and stability of proteases produced by Dichelobacter (Bacteroides) nodosus

Previously reported tests to distinguish thermostable and thermolabile proteases of Dichelobacter nodosus used hide powder azure as a test substrate. This paper describes an alternative test for protease stability using gelatin, an inexpensive and convenient substrate. The test required less equipment and time than the hide powder tests, and simplified the testing of multiple samples. Proteases from 2965 isolates of D. nodosus from samples collected as part of a footrot eradication scheme were tested using the gelatin method, 1707 produced thermostable, and 1258 produced thermolabile protease. Production of thermostable protease was used to identify isolates of D. nodosus which had the potential to cause the virulent form of ovine footrot. Comparisons were made with a hide powder test on 47 isolates. Further characterisation of all proteases was undertaken using polyacrylamide gel electrophoresis. Isoenzyme patterns of thermostable protease producing isolates were identified as S1 (1688 isolates) and S2 (19) whilst thermolabile protease producing isolates showed patterns U1 (1104 isolates), U2 (40), U3 (32), U4 (47), U5 (6), U6 (28) and S1 (1).

Possible beta-mannosidosis chimera. Altered expression of metabolic perturbations

An aberrant beta-mannosidosis phenotype in a 5-month-old triplet goat kid was characterized by a late postnatal onset of mild neurological symptoms. Necropsy examination revealed relatively normal myelination; however, the distribution of cytoplasmic vacuolation in the kidney and brain was similar to that observed in neonatal beta-mannosidosis. Variable engraftment of donor stem cells, resulting from transplacental transfusion of stem cells from a normal sibling during the immunotolerant period, may have modified the expected severe beta-mannosidosis phenotype. This investigation was designed to determine the effects of a possible chimeric state on organ-specific metabolic perturbations. Residual beta-mannosidase enzyme activity was found in plasma, kidney, liver and spleen but not in brain. Other lysosomal enzyme activities were comparable to normal values. Immunoreactive beta-mannosidase was estimated to be less than 10% of normal levels. Kidney, brain grey matter and brain white matter contained 33%, 12% and 4%, respectively, of the oligosaccharides expected in the organs of beta-mannosidosis animals. There were no detectable oligosaccharides or cytoplasmic vacuolation in the liver or spleen. Studies of this possible chimera provided preliminary evidence for the efficacy of prenatal treatment of early-onset neurodegenerative disorders.

The role of prostaglandin H synthase in 3-methylindole-induced pneumotoxicity in goat

1. Aspirin and indomethacin were used to investigate the role of prostaglandin H synthase (PHS) system in 3-methylindole (3MI)-induced pneumotoxicity. 2. A functional test was developed to detect the inhibitory effect of oral doses of aspirin and indomethacin on PHS activity based on thromboxane B2 (TXB2) production from thrombin-stimulated platelets in whole blood. 3. Goats which received oral doses of aspirin or indomethacin before administration of 3MI (0.1 g 3MI/kg body wt) showed a reduced severity in clinical signs and pathological lesions in the lung than those that received 3MI alone. 4. There was no difference in the severity of the disease between the control and the aspirin-treated animals if aspirin was given after 3MI administration. 5. The protective effect of inhibitors when administered before, but not after, 3MI dosing suggests it is the inhibition of PHS activity in activation of 3MI, not in production of prostanoids which prevented the disease process.

Enzootic nasal tumour of goats: demonstration of a type D-related retrovirus in nasal fluids and tumours

Nasal exudate and tumour tissue from goats with enzootic nasal tumours were shown to contain a reverse transcriptase activity associated with a particle of buoyant density typical of retroviruses. The same particle contained a 25,000 Mr protein that cross-reacted with the p27 of Mason-Pfizer monkey virus (MPMV) and with p25 of sheep pulmonary adenomatosis retrovirus. It also contained a low Mr protein related to p10-12 of MPMV.

Biochemical alterations in serum and cerebrospinal fluid in experimental acidosis in goats

Experimental acidosis was induced in six goats aged between one and two years by administration of whole wheat grain at 100 g kg-1 bodyweight given intraruminally. Blood and cerebrospinal fluid (CSF) samples were collected from these goats before administration of wheat grain (0 hour) and thereafter at 12, 24, 48, 72, 96 and 120 hour intervals. These were analysed for serum enzyme activities and physicochemical characters of CSF. Significantly (P less than 0.05) higher activities of amylase (at 12 hours), lactate dehydrogenase (12 to 48 hours), creatine phosphokinase (12 to 48 hours), aspartate aminotransferase (12 to 24 hours), and gamma-glutamyl transferase (12 to 96 hours) were found in serum samples of acidotic goats. Changes in CSF included decrease of pH and chloride content and higher glucose values. No difference was seen in the physical character of CSF collected at different time intervals from acidotic goats.

Caprine beta-D-mannosidosis: characterization of a model lysosomal storage disorder

Interest in using caprine beta-D-mannosidosis as a model to evaluate bone marrow transplantation in the treatment of human lysosomal storage disorders provided the stimulus for characterization of beta-D-mannosidase in selected goat tissues and induction of hemopoietic chimerism in the goat. Total beta-D-mannosidase activity was measured with the use of 4-methylumbelliferyl beta-D-mannopyranoside as substrate. Residual activity in mutant liver was 52% of control but no activity was detectable in mutant kidney or brain tissue. Normal adult goat liver contained two forms of beta-D-mannosidase, a nonlysosomal form (52%) with a broad pH range for optimum activity (4.5-8.0) and a lysosomal form (48%) with a pH optimum of 5.5. Residual enzyme in mutant liver consisted entirely of the nonlysosomal form. Normal adult thyroid, kidney and brain contained two major lysosomal isoenzymes with pIs 5.5 and 5.9 and traces of a minor isoenzyme with pI 5.0. Normal liver contained three isoenzymes with similar pIs; however, an isoenzyme with pI 5.0 predominated. In 60-day fetal liver lysosomal isoenzymes predominated and only trace amounts of nonlysosomal isoenzyme were detectable. Total hepatic beta-D-mannosidase activity increased towards adult levels during the last 90 days of gestation as a result of increasing nonlysosomal isoenzyme activity. Intraperitoneal injection of fetal liver cells into 60-day goat fetuses resulted in sustained hemopoietic chimerism in surviving kids without evidence of graft-versus-host-disease. These results suggest that transplantation of normal fetal liver cells into preimmunocompetent goat fetuses affected with beta-D-mannosidosis is feasible and may provide an alternative strategy for evaluation of postnatal bone marrow transplantation in the treatment of human lysosomal storage disorders.