Reduction of bacterial infections in newly hatched chicks by the use of antimicrobial dips: preliminary approaches

Bacteriological examination of hatchery waste eggs, identification of the isolated bacteria, and susceptibility testing against seven antimicrobial agents were used in an attempt to establish a rational basis for reducing bacterial infections in newly hatched chicks. Chloramphenicol at 1000 ppm was selected as the antibiotic for preliminary dipping trials and 0.45% iodophore (Wescodyne) was added for later trials. The control treatment consisted of formaldehyde fumigation. The following conclusions can be drawn: Hatchery waste eggs are highly contaminated (69.1%) and enterobacteriaceae predominate (26.6%). Chloramphenicol is the most effective antimicrobial tested. Dip treatments with either chloramphenicol alone or chloramphenicol plus Wescodyne result in a reduced percentage of abnormal navels (8.4% and 10.4%), as compared with 21.9% for the control treatment. Hatchability of either group of dipped eggs is reduced in comparison with fumigated eggs. Dip treatment with chloramphenicol plus Wescodyne significantly reduces the anal carrier rates for Escherichia coli, Pseudomonas aeruginosa, Salmonella spp., and Staphylococcus aureus. This treatment reduces the incidence of bacterial infection in abnormal navels to zero.     

Distribution of paratyphoids on Saudi Arabian poultry farms and pathogenicity studies of predominant serotypes

A total of 412 feed samples and 632 litter samples from 15 poultry farms (2 breeding farms and 13 rearing farms) were examined for salmonella. Twelve of these farms had salmonella in litter, five farms had salmonella in the feed and four had salmonella in both feed and litter. Seventeen feed samples (4.13%) and 121 litter samples (19.15%) were contaminated with salmonella. Sixteen salmonella serotypes were encountered, of which six were found in both feed and litter. Salmonella concord and S. livingstone were present in the litter of one breeding farm and its progeny farms. The five most frequently isolated salmonella serotypes in feed and litter were S. concord (17.39%), S. coeln (15.94%), S. livingstone (15.22%), S. manhattan (11.59%), and S. paratyphi B var. java (8.69%). The pathogenicities of those serotypes were determined by calculating their median lethal doses (LD50) 24 and 48 hr postinjection of 1,050 one-day-old broiler chicks via the navel into the yolk sac. The composite 48-hr LD50s (viable cells) were: S. concord, less than 8.8 X 10(3); S. livingstone, 1.1 X 10(5); S. manhattan, 3.5 X 10(5); S. coeln, 1.25 X 10(7); and S. paratyphi B var. java, 1.73 X 10(7).     

Linear plasmids of the bacterium Borrelia burgdorferi have covalently closed ends

The genetics of spirochetes, a division of eubacteria, has been little studied. Double-stranded linear plasmids were found in Borrelia burgdorferi, the agent of Lyme disease. A 49-kilobase linear plasmid contained the ospA and ospB genes, which encode the major outer membrane proteins of strain B31. Molecules of the 49-kilobase plasmid rapidly reannealed after alkaline denaturation; rapid renaturation was prevented if the 49-kilobase plasmids were first treated with S1 nuclease. When denatured plasmid molecules were examined directly, single-stranded circles of approximately 100-kilobase circumference were seen. These studies provide direct visual evidence that the linear plasmids have covalently closed ends. This form of DNA occurs in some animal viruses, but it has not heretofore been described in prokaryotic organisms.     

Identification of the antigenic components of paramyxovirus-3, paramyxovirus-6 and Newcastle disease virus in turkeys

The aim of this study was to use the enzyme-linked immunosorbent assay (ELISA) and the Western immunoblotting as possible tools to differentiate infections in turkeys by different paramyxoviruses. Pooled hyperimmune sera of turkeys infected with either paramyxovirus-3 (PMV-3), paramyxovirus-6 (PMV-6), or Newcastle disease virus (NDV) were assayed for antibodies specific to the three viruses by the ELISA and Western immunoblotting. ELISA results showed cross reactions of turkey antibodies between PMV-3 and PMV-6 antigens, while turkey antibodies to NDV did not cross-react with any of the other paramyxoviruses. The immunoblots of sera from birds infected with PMV-3 (Minnesota turkeys and Iowa chickens) reacted to low molecular weight polypeptides of PMV-3 of 29, 32, and 34 kDa, and to a high molecular weight band of 200 kDa. The same Minnesota turkey sera had a cross reaction to the 200 kDa polypeptide of PMV-6, while the Iowa chicken sera did not. Both sera had no apparent reaction to NDV proteins. Western immunoblotting showed that the turkey PMV-3 sera had a specific reaction to a 220 kDa polypeptide present in PMV-3, but not in PMV-6, while the turkey PMV-6 sera had a specific reaction to a 130 kDa polypeptide present in PMV-6, but not in PMV-3. Immunoblots of pooled sera from turkeys infected with PMV-6 (Minnesota source) reacted to the 200 kDa protein present in both PMV-3 and PMV-6; however, no reaction occurred between this sera and NDV proteins.(ABSTRACT TRUNCATED AT 250 WORDS)     

Partial decontamination of rotifers with ultraviolet radiation: the effect of changes in the bacterial load and flora of rotifers on mortalities in start-feeding larval turbot

Exposure of the rotifer Brachionus plicatilis to ultraviolet radiation in 1 mm deep liquid layers at an energy intensity of 38 mW cm⁻² reduced the rotifer bacterial load by >90% within 2 min. Such radiation doses had no significant effect upon rotifer viability, fatty acid composition, swimming or feeding activity. The surviving bacterial flora of irradiated rotifers was similar to that of un-irradiated rotifers and there was no evidence of major differences in sensitivity to ultraviolet radiation between different bacteria. For irradiation of large numbers of rotifers, a flow-through cell was used, operated with rotifer densities of 200 ml⁻¹ and a flow rate of 1.5 l min⁻¹. In two separate field trials involving groups of 34,000 turbot larvae per group, higher survival was found in groups receiving ultraviolet-irradiated rotifers in which the bacterial load was reduced by 88%. This was attributed to the slower rate of colonisation of the larval gut by bacteria, as a consequence of the lower bacterial load on the rotifers. Attempts to introduce specified bacteria into the larval turbot gut in significant numbers by colonisation of either normal or irradiated rotifers with particular bacteria were unsuccessful.     

Genetic diversity, seed traits and salinity tolerance of Millettia pinnata (L.) Panigrahi, a biodiesel tree

The leguminous tree, Millettia pinnata (pongamia) produces oilseed suitable for biodiesel production. Assessment of oil production and genetic, morphological and physiological traits are required. Collections from the Forest Products Commission in Kununurra, Western Australia were compared with accessions from India, Indonesia, Queensland and the Northern Territory in Australia. Molecular diversity, examined using the internal transcribed spacer region, indicated distinctiveness of genotypes from Java, Indonesia. Seed traits varied across trees with the smallest seeds from Indonesia and the largest from Kununurra. Oil content varied across trees with a minimum of 28 % in an Indonesian accession and the highest of 45 % from Kununurra. Major fatty acids across trees were oleic (51 %), linoleic (19 %), palmitic (11 %) stearic (6 %), linolenic (4.5 %) and behenic (4.5 %) acids. Seed weight and oil content per seed of developing seeds increased with a sigmoid pattern and oleic acid was the major fatty acid throughout seed development. Waterlogging and salinity tolerance were assessed. Four month-old seedlings from Kununurra, Western Australia and India were exposed to: non-saline drained control, saline drained, non-saline waterlogged and saline waterlogged treatments. Seedlings were waterlogging tolerant. Salt, applied in weekly increments of 50 mM, led to reduced survival, height growth rate, leaf number and stomatal conductance and increased concentrations of leaf Na⁺ and Cl^?. Salinity tolerance was 200 mM NaCl under saline drained and 150 mM NaCl under waterlogged conditions. Milletia pinnata diversity could be exploited for selection of superior genotypes for oil production on marginal land.