Induction of early immunopotentiation to Fimbriae of Salmonella Enteritidis (SE) by administering thymulin and zinc to SE-vaccinated chicken breeders: relationship to protection

The purpose of this study is to attempt the induction of early immunopotentiation of antibodies specific to fimbriae of Salmonella enterica serovar Enteritidis (SE), by administering thymulin and zinc to SE-vaccinated chicken breeders, and the improvement of protection against a controlled-live challenge by SE. The first two groups of breeders were administered subcutaneously at 15 and 19 weeks of age a killed SE vaccine. Breeders of the third and fourth groups were left unvaccinated. Breeders of the first group, immunopotentiated by thymulin and zinc, were able to induce the earliest antibodies in their pooled sera at 2 weeks post the first SE-vaccination, specific to fimbriae (approximately 21 KDa) of SE. However, the second group that was only vaccinated with the same SE-vaccine produced specific antibodies to fimbriae at 3 weeks following the second vaccination (22 weeks of age). Breeders of the third group, that were neither SE-vaccinated nor immunopotentiated by thymulin and zinc, but were challenged by live SE at 22 weeks of age, were able to show specific antibodies to fimbriae at 3 weeks post challenge (25 weeks of age). The fourth group that was deprived of SE-vaccination, immunopotentiators, and challenge didn't show any background antibodies specific to SE-fimbriae. The presence of the earliest antibody-immunopotentiation to fimbriae of SE in breeders of the first group, administered thymulin and zinc, was associated with the lowest frequency of SE-infected ceca (10%) among the challenged groups. In addition, breeders of the first group were the only challenged birds resulting in absence of SE infection in their cecal tonsils. The first group-vaccinated, immunopotentiated, and challenged, and the second group-vaccinated and challenged only resulted in breeders with absence of SE infection in their oviducts and spleens. In conclusion, immunopotentiation of chicken breeders by thymulin and zinc induces the earliest specific antibodies to fimbriae of SE associated with the lowest frequency of SE-infected ceca, and absence of SE infection from cecal tonsils, oviducts and spleens.     

Breed differences and genetic parameters for melting point, marbling score and fatty acid composition of lot-fed cattle

Fatty acid composition, marbling score and melting point data collected between 1994 and 1996 were analysed. The data were from the adipose tissue of 764 Angus, Belgian Blue, Hereford, Jersey, Limousin, South Devon and Wagyu crossbred cattle slaughtered after lot‐feeding at 500 days of age. The aim was to investigate sire‐breed differences and to estimate heritability and genetic and phenotypic correlations. Significant breed differences were found: Jersey crosses had the highest marbling score and Belgian Blue crosses had the lowest. Limousin crosses had the highest melting point and Jersey crosses the lowest. South Devon crosses had the highest proportion of stearate and Jersey crosses the lowest. Desaturation indices in C16 and C18 fatty acids were highest in Jersey crosses and lowest in Limousin and South Devon crosses. In contrast, there were no breed differences in the proportions of palmitate, oleate, total saturated, total mono‐unsaturated fatty acids and elongation index. Heritability estimates of individual fatty acids and their summations, melting point and marbling were low to moderately low (0.05–0.27). Strong genetic correlations of melting point and desaturation index in C16 fatty acids (‐0.93), melting point and stearate (0.62), marbling and stearate (‐0.71) and marbling and desaturation index in C18 fatty acids (0.62) were observed. Phenotypic correlation were generally low. The results imply that fatty acids in the adipose tissue of lot‐fed cattle have a moderately low heritability, hence genetic progress might be slow.     

Collagen fragmentation in ruptured canine cranial cruciate ligament explants

Collagen fragmentation in cranial cruciate ligament (CCL) explants and stifle synovial fluid was investigated in dogs with ruptured and intact CCL. Cathepsin K and tartrate-resistant acid phosphatase (TRAP) activities were determined in CCL explant supernatants. Formation of collagen fragments was determined in explant supernatants and stifle synovial fluid. Cathepsin K(+) and TRAP(+) cells were stained specifically in histological sections of CCL. Formation of telopeptide collagen fragments was increased in ruptured CCL explants and stifle synovial fluid from dogs with ruptured CCL. In ruptured CCL explants, release of collagen fragments was associated with extracellular release of TRAP and the presence of cathepsin K(+) cells within CCL tissue. Cathepsin K(+) and TRAP(+) cells were only seen in ruptured CCL. It was concluded that infiltration of the CCL with TRAP(+) cells in dogs with CCL rupture is associated with increased collagenolysis. It is hypothesized that recruitment and activation of TRAP(+) mononuclear cells within the synovium and CCL precipitates CCL rupture through upregulation of collagenolytic enzymes and collagen degradation.     

Resistance to drought of mollusks of the genus Bulinus, vectors of human and animal trematode infections in Senegal. II. Study under natural conditions in the North-Sudan area. Ecology and resistance to drought of Bulinus umbilicatus and B. senegalensis

The authors report on the results of a 2-year study on the ecology and resistance to drought of B. umbilicatus and B. senegalensis on 3 temporary ponds in the North-Sudan area (region of Tambacounda, Senegal). The variations in some abiotic factors like the temperature and the pH of water do not seem to have a strong influence on the ecology while rainfall has a great importance on the distribution and the density of molluscs. As a fact, the quantity of water and the drying out period of these ponds depend upon rain factors which rule the existence and the survival of the malacological fauna. In the second part of the rainy season, the population reaches its maximum, i.e., during the reproduction period. Monthly observations show that the relative abundance of B. umbilicatus is higher than that of B. senegalensis. These ponds are dry during 6 to 8 months per year. However the populations of molluscs regenerate regularly, a fact which presupposes a certain ability to resist drought. Some come through this period successfully, but the middle-sized ones (7 to 9.9 mm) resist better than others (70 to 80 per cent of the population). Immediately after the first rains they resume their activity and lay intensively in order to reconstitute the population. B. umbilicatus and B. senegalensis are potential intermediate hosts for human and animal trematode infections, but in the studied region only B. umbilicatus intervenes in the transmission of S. haematobium and S. curassoni which occurs between September and November. Under natural Sahel conditions the epidemiological cycle is short and everything happens within 4 to 6 months with the regeneration and the growth of the population of molluscs, its infestation and the transmission of trematode infections. The ecological behaviour of these molluscs in the North-Sudan region is very important in the epidemiology of human and animal trematode infections and requires a new controlling strategy. The destruction of molluscs is more effective and more economic at the end of the rain season, which is the beginning of the drying of ponds, a period in which they concentrate in the residual water pools.     

Evaluation of agreement between numerical rating scales, visual analogue scoring scales, and force plate gait analysis in dogs

Objective— To evaluate the accuracy of numerical rating (NRS) and visual analogue (VAS) scoring scales compared with force plate gait analysis and agreement between observers for each scoring scale.
Study Design— Experimental study.
Animals— Mixed breed dogs (n=21) with a right limb tibial osteotomy repaired with an external fixator.
Methods— Three small-animal veterinarians with orthopedic training scored lameness using NRS and VAS before surgery, and at 4 and 8 weeks after surgery. Peak force and impulse were determined at the same time points using a force plate. Agreement between observers and with force plate data was assessed. Significance was set at P ≤.05.
Results— Agreement was generally low among observers for both NRS and VAS scores. When evaluated at each time point, an acceptable level of agreement was present only at 4 weeks after surgery. Only impulse had a significant relationship with some of the observers' subjective scores. No significant relationships between any observer's scores and force plate data existed if very lame dogs were omitted.
Conclusions— Subjective scoring scales do not replace force plate gait analysis. Agreement is low unless lameness is severe, and each observer uses an individually unique scale. Subjective scoring scales most accurately reflect force plate gait analysis when lameness is severe.
Clinical Relevance— Subjective lameness scoring scales may not accurately reflect lameness and do not replace force plate gait analysis. Observers must stay the same during the duration of a study for accurate analyses.     

Hemodynamic effects of ionized calcium in horses anesthetized with halothane or isoflurane

OBJECTIVES: To evaluate the effects of halothane and isoflurane on cardiovascular function and serum total and ionized calcium concentrations in horses, and to determine whether administration of calcium gluconate would attenuate these effects. ANIMALS: 6 clinically normal adult Thoroughbreds. PROCEDURE: Catheters were inserted for measurement of arterial blood pressures, pulmonary arterial blood pressures, right ventricular pressure (for determination of myocardial contractility), right atrial pressure, and cardiac output and for collection of arterial blood samples. Anesthesia was then induced with xylazine hydrochloride and ketamine hydrochloride and maintained with halothane or isoflurane. An i.v. infusion of calcium gluconate was begun 75 minutes after anesthetic induction; dosage of calcium gluconate was 0.1 mg/kg of body weight/min for the first 15 minutes, 0.2 mg/kg/min for the next 15 minutes, and 0.4 mg/kg/min for an additional 15 minutes. Data were collected before, during, and after administration of calcium gluconate. RESULTS: Halothane and isoflurane decreased myocardial contractility, cardiac index, and mean arterial pressure, but halothane caused greater depression than isoflurane. Calcium gluconate attenuated the anesthetic-induced depression in cardiac index, stroke index, and maximal rate of increase in right ventricular pressure when horses were anesthetized with isoflurane. When horses were anesthetized with halothane, a higher dosage of calcium gluconate was required to attenuate the depression in stroke index and maximal rate of increase in right ventricular pressure; cardiac index was not changed with calcium administration. CONCLUSIONS AND CLINICAL RELEVANCE: I.v. administration of calcium gluconate may support myocardial function in horses anesthetized with isoflurane.     

Estimate of the variability of the lysine requirement of growing pigs using the indicator amino acid oxidation technique

Although AA requirements for the mean in a population of growing pigs are well established, there are no direct estimates of their variability within the population. The indicator AA oxidation method allows repeated measurements in a short period of time so that the AA requirement can be determined for individual pigs. The objective was to determine the Lys requirement in individual pigs to derive a first estimate of the population mean requirement and its variability. Nine individually housed barrows (15 to 18 kg) were surgically implanted with venous catheters for isotope infusion. Pigs were offered, in random order, isonitrogenous and isoenergetic diets with one of seven Lys concentrations (4.8 to 15.5 g of Lys/kg diet, as-fed basis). The pigs were fed twice daily, except for study days when they received one-half of the daily allowance in eight equal hourly meals. After a validated minimum adaptation period, indicator (Phe) oxidation was determined for each dietary Lys level during a 4-h primed, constant infusion of L-[1-(14C)]Phe at a rate of 464 kBq/h. The Lys requirement was calculated using a two-phase linear regression crossover analysis within individual pigs. For each pig, Phe oxidation decreased linearly (P < 0.02) as the dietary Lys concentration increased until the requirement was reached; thereafter, Phe oxidation was not different. The true ileal digestible Lys requirement ranged from 7.5 to 10.6 g/kg of diet (as-fed basis) for the nine animals. The mean requirement for all pigs was 9.1 g/d (CV, 11.6%) or 93.9% (CV, 9.8%) of the predicted (NRC, 1998) requirement based on each pig's mean BW and energy intake. The measured and predicted requirements did not differ. The indicator AA oxidation method gave values for Lys requirement similar to conventional methods. The short (< 3 wk) experimental period allows, for the first time, the estimate of population variability, which provides for more accurate calculation of the effect of altering Lys intake on herd performance and production economics. This method is suitable to use with all dietary indispensable AA.     

Leishmania major infections in Phlebotomus duboscqi fed on murine models immunized with L. major subcellular antigens and sandfly gut antigens

The ability of antibodies in bloodmeals of mice and hamsters immunized with Leishmania major subcellular fractions and sandfly (Phlebotomus duboscqi) gut antigens to inhibit development of L. major in its vector P. duboscqi was examined. Antibodies from animals immunized with either L. major subcellular fractions alone or sandfly gut antigen alone were not very effective in inhibiting development of L. major in the sandfly. When P. duboscqi were fed on blood from animals immunized with both parasite flagella and sandfly gut antigen, development of L. major was significantly inhibited (P<0,05). Control sandflies fed on naive animals displayed a normal pattern of parasite development to the metacyclic stage. Electron microscopy studies showed that one of the mechanisms through which antisandfly gut antibody can cause inhibition of parasite development is by lysing sandfly gut epithelium. This study has demonstrated that it is possible to reduce transmission of leishmaniosis through immunization against both the parasite and its sandfly vector.     

Describing the within laboratory and between laboratory agreement of a serum ELISA in a national laboratory network

Results from laboratory assays for detection of animal disease are often assessed for repeatability (agreement within laboratory) and reproducibility (agreement between laboratories). This work aimed to understand the strengths and limitations of available methods for describing these quantities. Five major veterinary laboratories in Australia volunteered to participate in a designed evaluation based on repeat testing of twenty bovine sera. Sampling was stratified so that ten of the sera were negative to the virus neutralisation test (VNT) for antibody to bovine herpes virus 1 (BHV-1) and the remaining ten sera were VNT positive. Each serum was divided into 50 replicates and each laboratory assayed one replicate of each serum on a weekly basis using a commercial ELISA for BHV-1. Laboratories were blinded to the identity of sera. The data on sample to positive control ratio (S/P) for these 1000 individual assays were collated, sources of variance analysed using a random effects model, and reliability coefficients (ρ) obtained from the variance estimates as quantitative measures of within and between laboratory agreement. Coefficient of variation (CV) was calculated for combinations of sera and laboratory. CV was found to be higher for sera with the lowest mean S/P values (VNT -ve sera). For VNT -ve sera, agreement of S/P within laboratory was low to moderate (ρ: 0.01-0.27) and the agreement between all labs was low (ρ=0.02). Reliability coefficients for VNT +ve sera were very high for agreement within laboratories (ρ: 0.63-0.92) and moderate for agreement between laboratories (ρ=0.52). As well, simulation demonstrated that sero-prevalence has a dramatic affect on the reliability coefficient if sampling were to be irrespective of VNT status. We conclude that there are some limitations with the available approaches for assessing agreement within and between laboratories. Although reliability coefficients have some drawbacks they are an attractive way of reducing reliance on subjective assessment of agreement.     

Multivariate analysis of sexual size dimorphism in local turkeys (Meleagris gallopavo) in Nigeria

Sexual size dimorphism is a key evolutionary feature that can lead to important biological insights. To improve methods of sexing live birds in the field, we assessed sexual size dimorphism in Nigerian local turkeys (Meleagris gallopavo) using multivariate techniques. Measurements were taken on 125 twenty-week-old birds reared under the intensive management system. The body parameters measured were body weight, body length, breast girth, thigh length, shank length, keel length, wing length and wing span. Univariate analysis revealed that toms (males) had significantly (P < 0.05) higher mean values than hens (females) in all the measured traits. Positive phenotypic correlations between body weight and body measurements ranged from 0.445 to 0.821 in toms and 0.053–0.660 in hens, respectively. Three principal components (PC1, PC2 and PC3) were extracted in toms, each accounting for 63.70%, 19.42% and 5.72% of the total variance, respectively. However, four principal components (PC1, PC2, PC3 and PC4) were extracted in hens, which explained 54.03%, 15.29%, 11.68% and 6.95%, respectively of the generalised variance. A stepwise discriminant function analysis of the eight morphological traits indicated that body weight, body length, tail length and wing span were the most discriminating variables in separating the sexes. The single discriminant function obtained was able to correctly classify 100% of the birds into their source population. The results obtained from the present study could aid future management decisions, ecological studies and conservation of local turkeys in a developing economy.