Attached and free-liviing dividing bacteria in two aquatic systems

The percentage of dividing biomass was calculated for attached and free-living bacteria, in a coastal marine and a freshwater system. In the marine system with low concentrations of total and dissolved organic carbon (TOC and DOC) the percentage of dividing biomass was higher for attached (41.4 ± 13.9) than for the free-living bacteria (22.0 ± 11.7). However, in the freshwater system, which had a higher concentration of TOC and DOC, the percentage of dividing biomass was similar for both communities-attached (53.4 ± 26.5) and free-living (78.4 ± 21.9). Thus the attachment to particulate material is not necessarily an advantage in waters where dissolved organic nutrients are readily available.     

Predation rates of flagellate and ciliated protozoa on bacterioplankton in a river

Abstract Predation rates of flagellate and ciliate protozoa on the bacterioplankton of Butrón River (Spain) were determined from FLB (fluorescently labelled bacteria) uptake rates. Bacterial and ciliate protozoa counts were higher when higher water temperature was recorded. Flagellate counts did not show this pattern, which suggested predation of flagellates by other organisms, or some other different nutritional mode besides phagotrophy. Average individual ciliate predation rates were up to 40-times higher than those of flagellates. These results were compared with similar data obtained from other authors in several aquatic systems. However, the population predation rates of flagellate protozoa were on average 6-times higher than that of ciliate protozoa, due to the low population numbers of the latter. Thus, flagellate protozoa can be considered as more important bacterial consumers than ciliates in this aquatic system.     

Variations in Haematological Parameters and Erythrocyte Osmotic Fragility of Pigs during Hot-Dry and Harmattan Season in Northern Guinea Savanna Zone of Nigeria

Experiments were performed with the aim of investigating the effect of season on haematological parameters and erythrocyte osmotic fragility (EOF) of pigs. A total of 23 local pigs including males, non-pregnant and non-nursing females, aged 9 to 12 months were used for the study, ten animals were used during the hot-dry season and thirteen during the harmattan season. Blood sample was taken from each animal for the determination of EOF and other haematological parameters as well as total protein. The PCV value of 39.7±1.9 % obtained during the hot-dry season was significantly higher than 32.00 ± 0.9 % obtained during the harmattan season. Total leucocyte count of 18,836.5±1727.1 obtained during the harmattan season was higher than the value 15,920.00±1119.1 recorded during the hot-dry season. The neutrophil:lymphocyte ratio value was significantly higher during the harmattan season, with a value of 0.61±0.0 than the recorded value of 0.43±0.0 during the hot-dry season. The percentage haemolysis values obtained during the harmattan season at NaCl concentration of 0.5-0.9 % with a value of 92.03±0.02 % respectively were significantly higher than those recorded during the hot-dry season. In conclusion, the haematological values showed that harmattan season was more stressful to pigs than the hot-dry season in the Northern Guinea Savanna zone of Nigeria.     

Effects of heat stress on some blood parameters and egg production of Shika Brown layer chickens transported by road

The effects of vitamins C and E on layer chickens transported by road for 6 h during the hot dry season were investigated. Two experimental groups consisting of thirty Shika Brown layers were separately administered vitamins C and E orally just before transportation, while another 30 layers, which were only given sterile water, served as control. Blood samples analyzed before and after transportation in the control layers showed a decrease (p<0.05) in total white blood cell, (p<0.01) lymphocyte and monocyte values, and a significant (p<0.05) and (p<0.001) increase in the values of eosinophils and heterophils post-transportation, respectively. In the experimental groups, post-transportation values of total white blood cells, eosinophils and monocytes were not different (p>0.05) from those obtained before transportation. Heterophil/lymphocyte values were highest in the control group. The result showed that transportation was stressful for the control layers. Post-transportation egg production was not significantly (p>0.05) different in the vitamin E treated group, but values recorded for the vitamin C and control groups were significantly (p<0.05) and (p<0.001) reduced compared to pre-transportation. In conclusion, vitamins C and E administration ameliorated the adverse effect of road transportation stress during the hot dry season.     

Assessment of thermal load on transported goats administered with ascorbic acid during the hot-dry conditions

The major factor in the induction of physiological stress during road transportation of livestock is the complex fluctuations of the thermal transport microenvironment, encountered when animals are transported across different ecological zones. Recommended guidelines on optimum “on-board” conditions in which goats should be transported are lacking, and there are no acceptable ranges and limits for the thermal loads to which goats may be subjected during long-distance road transportation in hot-dry conditions. Panting score (PS), rectal temperature (RT), heart rate (HR) and respiratory rate (RR) were employed as reliable stress indices to assess the effects of different thermal loads, measured as temperature humidity index (THI), encountered in the vehicle during 12 h of road transportation of 40 goats, and to suggest the administration of 100 mg/kg body weight of ascorbic acid (AA) as an ameliorating agent. The results obtained showed that the PS, RT, HR and RR rose above normal reference values with increase in the THI and journey duration. The rise in PS value, which is a visual indicator of the severity of thermal load, was the most pronounced. The results suggest that values of THI in the vehicle up to 94.6 constitute no risk, while at of 100 it presents a moderate risk and above 100 may result in severe stress. The relationships between the thermal load and the physiological variables were positive and significant (P < 0.05). They reflect the degree of stress imposed by each THI value during the transportation, and may be used as recommended ranges and limit thermal load values in transported goats. The results demonstrated that administration of 100 mg/kg body weight of AA before road transportation mitigated the risk of adverse effects of high THI values and other stress factors due to road transportation in goats.     

Phylometabonomic patterns of adaptation to high fat diet feeding in inbred mice

Insulin resistance plays a central role in type 2 diabetes and obesity, which develop as a consequence of genetic and environmental factors. Dietary changes including high fat diet (HFD) feeding promotes insulin resistance in rodent models which present useful systems for studying interactions between genetic background and environmental influences contributing to disease susceptibility and progression. We applied a combination of classical physiological, biochemical and hormonal studies and plasma (1)H NMR spectroscopy-based metabonomics to characterize the phenotypic and metabotypic consequences of HFD (40%) feeding in inbred mouse strains (C57BL/6, 129S6, BALB/c, DBA/2, C3H) frequently used in genetic studies. We showed the wide range of phenotypic and metabonomic adaptations to HFD across the five strains and the increased nutrigenomic predisposition of 129S6 and C57BL/6 to insulin resistance and obesity relative to the other strains. In contrast mice of the BALB/c and DBA/2 strains showed relative resistance to HFD-induced glucose intolerance and obesity. Hierarchical metabonomic clustering derived from (1)H NMR spectral data of the strains provided a phylometabonomic classification of strain-specific metabolic features and differential responses to HFD which closely match SNP-based phylogenetic relationships between strains. Our results support the concept of genomic clustering of functionally related genes and provide important information for defining biological markers predicting spontaneous susceptibility to insulin resistance and pathological adaptations to fat feeding.     

Novel phenotypes identified by plasma biochemical screening in the mouse

We used ENU mutagenesis in the mouse for the rapid generation of novel mutant phenotypes for both gene function studies and use as new animal models of human disease (Nolan et al. 2000b). One focus of the program was the development of a blood biochemistry screen. At 8-12 weeks of age, approximately 300 ml of blood was collected from F1 offspring of ENU mutagenized male mice. This yielded approximately 125 ml of plasma, used to perform a profile of 17 standard biochemical tests on an Olympus analyzer. Cohorts of F1 mice were also aged and then retested to detect late onset phenotypes. In total, 1,961 F1s were screened. Outliers were identified by running means and standard deviations. Of 70 mice showing consistent abnormalities in plasma biochemistry, 29 were entered into inheritance testing. Of these, 9 phenotypes were confirmed as inherited, 10 found not to be inherited, and 10 are still being tested. Inherited mutant phenotypes include abnormal lipid profiles (low total and HDL cholesterol, high triglycerides); abnormalities in bone and liver metabolism (low ALP, high ALP, high ALT, and AST); abnormal plasma electrolyte levels (high sodium and chloride); as well as phenotypes of interest for the study of diabetes (high glucose). The gene loci bearing the mutations are currently being mapped and further characterized. Our results have validated our biochemical screen, which is applicable to other mutagenesis projects, and we have produced a new set of mutants with defined metabolic phenotypes.     

Behavioral and hematological responses of broiler chickens administered with betaine and ascorbic acid during hot-dry season

Heat stress is a major problem in poultry production in tropical regions. Assessing the impact of thermally stressful environmental conditions on the welfare of broiler chickens is of great importance. Behavioral responses in a novel environment and hematology of broiler chickens administered with betaine and/or ascorbic acid (AA) during the hot-dry season were evaluated. Broiler chickens were randomly divided into four groups: Group I (control) was given sterile water, Group II was given betaine, Group III was given AA, and Group IV received betaine + AA orally and daily for 42 days. An open-field test was used to assess behavior. Hematological parameters were obtained using a hematology auto-analyzer. The natural environmental conditions were predominantly outside the thermoneutral zone for broiler chickens. Results demonstrated that treated groups exhibited improved ability to adjust faster to a new environment and better hematological responses than controls, evidenced by enhanced behavioral responses, oxygen-carrying capacity, and immune responses of broiler chickens under unfavorable environmental conditions. Betaine and/or AA administration to broiler chickens improved some behavioral responses, hemoglobin concentrations, packed cell volume, and total leukocyte count during the hot-dry season.     

Circadian rhythms of biomarkers of oxidative stress and their characteristics in broiler chickens reared under natural light/dark cycle

For the purpose of studying circadian rhythms of biomarkers of oxidative stress in broiler chickens maintained under natural photoperiod, we collected blood from the wing veins of 10 matured broiler chickens every three hours for a period of 24 h. The blood samples were analyzed for superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA). The fitting in of single cosinor procedure showed that CAT and MDA exhibited clear circadian rhythms, while SOD did not. The amplitude of daily rhythms for the parameters was small, while the acrophases were all restricted to the light phase of the light:dark cycle. In conclusion, to our knowledge, this is the first time investigation of the circadian rhythms of antioxidants in broilers chickens, reared under natural photoperiod in the tropics. The result may be exploited for a more precise targeting of reactive oxygen species, thereby offering better protection for the cells to combat oxidative stress.     

Succession of bacterivorous protists on laboratory-made marine snow

Colonization and succession over time by bacterivorous protistson laboratory-made marine snow were analysed in five assaysduring 1994. Marine snow was made hom natural seawater usingrolling tanks. In all experiments, the macroaggregates werestable in size and consistency after the fourth day, and thecolonization and succession processes were similar. Newly formedmacre aggregates became colonized by heterotrophic nanoflagellateson the fourth day, mmt of them kinete plastids (Bodo designisand Rhynchomonns nasuta) and bicosoecids (Pseudobodo tremulansand Bicosoeca sp.). Sarcodines and ciliates appeared 1 day later.Among the former, the most abundant genus was Vannella sp.,while scuticociliates (Uronema marinum) and hypotrichs (Euplotesvannus and Aspidisca steini) were the most abundant ciliates.Most of the species observed in the study were more common tobenthic habitats than to pelagic ones. The planktonic existenceof the genera Bodo, Rhynchomonas, Bicosoeca, Euplotes and Aspidiscadepends on the presence of surfaces because they are poor swimmersor immotile, and Pseudobodo and Vannella need attachment forfeeding. The only pelagic protist observed was Uronema, probablybecause its opportunistic behaviour leads it to exploit enrichedenvironments such as marine snow. Flagellate and ciliate abundancesin laboratory-made macroaggregates were much higher than insurrounding water, which indicates that marine snow representsan enhanced habitat for protist growth.