Skeleton of Euplectella sp.: structural hierarchy from the nanoscale to the macroscale

Structural materials in nature exhibit remarkable designs with building blocks, often hierarchically arranged from the nanometer to the macroscopic length scales. We report on the structural properties of biosilica observed in the hexactinellid sponge Euplectella sp. Consolidated, nanometer-scaled silica spheres are arranged in well-defined microscopic concentric rings glued together by organic matrix to form laminated spicules. The assembly of these spicules into bundles, effected by the laminated silica-based cement, results in the formation of a macroscopic cylindrical square-lattice cagelike structure reinforced by diagonal ridges. The ensuing design overcomes the brittleness of its constituent material, glass, and shows outstanding mechanical rigidity and stability. The mechanical benefits of each of seven identified hierarchical levels and their comparison with common mechanical engineering strategies are discussed.     

Effects of spray-dried animal plasma and immunoglobulins on performance of early weaned pigs

Five experiments were conducted to evaluate the effects of dietary spray-dried porcine plasma (SDPP) and spray-dried bovine plasma (SDBP) and their various molecular weight fractions on performance of pigs weaned at approximately 14 or 21 d of age. In addition, the efficacy of various levels of the immunoglobulin G (IgG)-rich fraction of SDPP and SDBP were evaluated. Experiment 1 evaluated the dietary addition of SDPP and three of its fractions (IgG-rich, albumin-rich, and low molecular weight fractions). Pigs fed SDPP grew faster and consumed more feed than the controls during the first week (P < 0.05). The IgG-rich fraction resulted in improvements in ADG and ADFI that were similar to those of pigs fed SDPP. The albumin-rich fraction had no effect on growth rate, but the low molecular weight fraction decreased feed intake as well as growth rate. Experiments 2 and 3 evaluated SDPP and graded levels of its IgG-rich fraction in pigs weaned at 21 or 14 d, respectively. In Exp. 2, pigs fed SDPP grew faster and consumed more feed than the controls during the first week (P < 0.05). Pig performance was enhanced with the addition of the IgG-rich fraction that provided 80% of the amount of IgG in the SDPP diet. In Exp. 3, there was no response to SDPP during the first week, but a positive growth response to SDPP (P < 0.01) occurred by the end of wk 2 (0 to 14 d). Feeding the IgG-rich fraction increased growth rate compared with controls (P < 0.05). Over the entire experiment, the greatest ADG occurred with the IgG-rich fraction that provided 128% of the amount of IgG provided by SDPP (quadratic; P < 0.05). Two additional experiments assessed feeding SDBP and bovine IgG-rich fractions to early weaned pigs. In Exp. 4, SDPP was superior to SDBP in stimulating growth and feed intake, but this difference did not occur in Exp. 5. In both experiments, the IgG fraction of bovine plasma seemed to be as effective at improving growth as SDPP and more effective than SDBP. The results indicate that both porcine and bovine plasma are beneficial to young pig performance during the first week after weaning and that the IgG fraction of plasma is the component that is responsible for the enhancement in growth rate and feed intake.     

Prevalence, incidence and geographical distribution of serovars of Salmonella on dairy farms in England and Wales

A study of randomly selected dairy farms in England and Wales was made between October 1999 and February 2001 to estimate the prevalence and incidence of Salmonella serovars. The farms were enrolled through five milk-buying companies, which represented 63 per cent of the dairy farms in England and Wales, and they were sampled on up to four occasions (449 farms at visit 1, 272 farms at visit 2, 251 farms at visit 3 and 243 farms at visit 4). In total, 19,296 samples of pooled faecal pats and slurry were collected. The farm-specific prevalence of all serovars of Salmonella ranged from 12.1 per cent (95 per cent confidence interval [CI] 8.2 to 16.0 per cent) to 24.7 per cent (95 per cent CI 19.4 to 30.1 per cent) at each visit. The most common serovars identified were Salmonella Dublin (3.7 to 6.6 per cent farm-specific prevalence at each visit), Salmonella Agama (1.8 to 7.6 per cent) and Salmonella Typhimurium (2.6 to 4.1 per cent) The prevalence varied by region and month of sampling and increased in late summer. The incidence rate of all serovars of Salmonella was 0.43 (95 per cent CI 0.34 to 0.54) cases per farm-year at risk. There was no significant difference between the incidence rates of the common serovars S Typhimurium (0.07), S Dublin (0.06) and S Agama (0.13). A total of 29 Salmonella serovars were isolated. Few of the isolates were resistant to the 16 antimicrobial agents tested, except the isolates of S Typhimurium dt104, of which 67.9 per cent were resistant to at least five of them.     

Virus-specific antiviral treatment for controlling severe and fatal outbreaks of feline calicivirus infection

OBJECTIVE: To test the life-sparing and therapeutic effect of a parenterally administered virus-specific antiviral phosphorodiamidate morpholino oligomer (PMO) for treating kittens during outbreaks of severe viral disease. ANIMALS: 112 kittens of various sex and age in 4 trials involving 3 outbreaks of naturally developing caliciviral disease. PROCEDURES: Each trial provided an opportunity to investigate the disease. A calicivirus isolated from the liver of a cat that died with hemorrhage and hepatitis was sequenced, and a PMO that had sequence specificity complementary to a 5' region was synthesized. In vitro efficacy of the PMO was tested against the isolate, followed by 3 trials in outbreaks of severe caliciviral disease. The PMO was administered starting on day 1 of disease onset (0.7 to 5.0 mg/kg, SC, q 24 h) and continuing for up to 7 days. Survival time, clinical recovery, and caliciviral shedding were compared by use of various antiviral dosages. In a fourth trial involving nonfatal disease, a control treatment was administered for comparison. RESULTS: In vitro blockage of caliciviral replication by the PMO was dose dependent. In trials 1 to 3 in which survival was the endpoint, 47 of 59 cats receiving PMO survived but only 3 of 31 survived without PMO treatment. Antiviral treatment reduced viral shedding and hastened clinical recovery, as measured by weight gains and clinical condition. CONCLUSIONS AND CLINICAL RELEVANCE: These data provided evidence that virus-specific PMOs were effective in treating kittens with severe Vesivirus disease and suggested a broader application for other viruses and species, including humans.     

Lack of transmission of porcine circovirus type 2 to weanling pigs by feeding them spray-dried porcine plasma

An experiment was conducted to determine whether spray-dried porcine plasma containing 2.47 x 10(5) dna copies of porcine circovirus type 2 (pcv-2) could infect weanling pigs when fed to them. Five specific pathogen-free (spf) weanling pigs were fed ad libitum for 45 days a control diet and six pigs were fed a test diet containing 8 kg sdpp per 100 kg feed. The two groups were housed in separate biosecurity level-3 rooms. None of the pigs in either group developed any clinical signs or became pcv-2 viraemic or seroconverted.     

Neonatal lamb mortality: major risk factors and the potential ameliorative role of melatonin

High incidences of pre-weaning mortality continue to limit global sheep production, constituting a major economic and welfare concern. Despite significant advances in genetics, nutrition, and management, the proportion of lamb deaths has remained stable at 15–20% over the past four decades. There is mounting evidence that melatonin can improve outcomes in compromised ovine pregnancies via enhanced uterine bloodflow and neonatal neuroprotection. This review provides an overview of the major risk factors and underlying mechanisms involved in perinatal lamb mortality and discusses the potential of melatonin treatment as a remedial strategy. Supplementing pregnant ewes with melatonin enhances uterine bloodflow and fetal oxygenation, and potentially birthweight and neonatal thermogenic capacity. Melatonin freely crosses the ovine placenta and blood-brain barrier and provides neuroprotection to the fetal lamb during periods of chronic and acute hypoxia throughout gestation, with improved behavioural outcomes in hypoxic neonates. The current literature provides strong evidence that maternal melatonin treatment improves outcomes for lambs which experience compromised in utero development or prolonged parturition, though to date this has not been investigated in livestock production systems. As such there is a clear basis for continued research into the effects of maternal melatonin supplementation during gestation on pre-weaning survival under extensive production conditions.     

The density of equine tissue at 37 degrees C.

The density of the following equine tissues was measured: white and grey brain matter, myocardium, lung parenchyma, liver, spleen, gastrointestinal tract and contents, renal medulla and cortex, muscle, fat, tendon and bone. Statistical analysis indicated that there were highly significant differences in the values for density between horses and between tissues within horses. Values for density of eight different muscles were obtained for 18 horses and these were shown to differ highly significantly between horses and between muscles within horses. The values for splenic density differed highly significantly between those for knackery killed horses and for the barbiturate killed post morten room horses.