Concentrations Of Total Bacteria Research Articles

Feeding and microbial disorders in horses: Part 3—Effects of three hay:grain ratios on microbial profile and activities

Cecal and colonic fluid contents were collected from three ponies and analyzed to determine the effects of three hay:barley ratios on their microbial and biochemical characteristics. Three diets based on chopped meadow hay and rolled barley were tested in a 3×3 Latin square experiment: 100% hay (100:0, 114gDM/KgBW 0.75/day), 70% hay-30% barley (70:30, 69gDM/KgBW 0.75/day) and 50% hay-50% barley (50:50, 58gDM/KgBW 0.75/day). Enumeration of total anaerobic and aero-anaerobic bacteria, lactate-utilizing and cellulolytic bacteria, lactobacilli and streptococci, as well as pH, lactate and VFA concentrations, were determined after 14 days adaptation to the new diet. In the large intestine, the concentrations of total bacteria were higher with the diets containing barley than with the hay diet, whereas cellulolytic bacteria were depressed with the concentrate diets. As the proportion of barley increased, concentration of lactate-utilizing bacteria, lactobacilli and streptococci increased in the colon while it did not interfere significantly on these populations in the cecum. These changes of the microflora were associated with a significant decrease in intestinal pH and [(acetate+butyrate)/propionate] ratio, and a numerical increase of lactate concentration.

Emissions of chemical compounds and bioaerosols during the secondary treatment of paper mill effluents.

This study identified and quantified the main chemical compounds--the substances responsible for the disagreeable odors--and the bioaerosols emitted during the biological treatment of paper mill effluents. It also identified the characteristics of the process that effects the generation or diffusion of these substances. All treatment stages were evaluated. Measuring sites were located as closely as possible to the potential emission sources. Measurements were taken in the summer in 11 paper mills during a 2- to 3-day period in each mill. Chemical compounds were evaluated by direct-reading instruments; bioaerosols were sampled by impaction and counted. Sulfur compounds, emitted into the air when the effluent or the sludge is stirred, had the highest concentrations; their presence was attributable to such things as kraft-type paper pulp. Next in concentration were the carbon and nitrogen oxides, ammonia, and some organic acids, produced by the action of microorganisms. These acids are found mainly in the sludge environment. Terpenes, which come from wood, are present at various locations in paper mills. Odor perception thresholds for most of these substances are much lower than those established to protect the health of workers. Significant concentrations of total bacteria, total molds, and endotoxins were measured at several sites. Gram-negative bacteria were high at only one site, whereas the mold Aspergillus fumigatus was occasionally present at low concentration. No actinomycetes bacteria were detected. The highest concentrations were measured where there was water or dust aerosolization. Emissions are therefore controlled by controlling the operations that lead to the dispersion of water and particles into the air.

Evaluation of Health and Safety Risks in Municipal Solid Waste Recycling Plants

ABSTRACT Designers and managers of recycling processing plants need to be informed about the inherent occupational health and safety risks; however, there are few studies in the literature describing these risks. Therefore, the objectives of this project were to document the biological, chemical, physical, and ergonomic risks in three household-waste recycling plants. Bioaerosols (molds and bacteria) were measured using the methodology recommended by the American Society for Testing and Materials (ASTM). Chemical contaminants and physical agents suspected of being present in this type of environment were measured using the standard methods of the Quebec Occupational Health and Safety Research Institute (IRSST). The ergonomic part of the study identified the work requirements and risk factors causing the workers' physical symptoms. In summer, the average concentrations of total bacteria were greater than the Scandinavian guideline of 10,000 colony forming units per cubic meter of air (CFU/m3) in the receiving areas in plants 1 and 3, in the sorting areas of the three plants, and in shipping in plants 1 and 3. When the average concentrations of Gram-negative bacteria were compared to the Scandinavian guideline of 1000 CFU/m3 of air, only the sorting department in plant 2 in summer exceeded this value. Average indoor concentrations of molds that were statistically significantly greater than those measured in the upwind outdoor air were measured in all departments in plants 1 and 3, regardless of the season, and only in sorting in plant 2 during the summer. The only chemical contaminant measured at average concentrations greater than 50% of the Threshold Limit Values (TLVs) proposed by the American Conference of Governmental Industrial Hygienists (ACGIH) was CO in the sorting departments in plants 1 and 2 during the winter. Noise exceeded the ACGIH TLV in plant 2. The workers' physical symptoms seem to be caused by the posture and effort required while remaining in a stationary position. Action must be focused on improving aspects such as work organization and personal protection and on informing citizens of the need for cleanliness of the material to be recycled.

VARIAÇÃO DA CONCENTRAÇÃO DE BACTÉRIAS INDICADORAS DE CONTAMINAÇÃO FECAL NAS DIVERSAS FASES DO PROCESSO DE TRATAMENTO DE ÁGUA DE ABASTECIMENTO PÚBLICO DA CIDADE DE ARARAQUARA - SÃO PAULO

O abastecimento de água de qualidade e em quantidade suficiente é de fundamental importância para a saúde da população. A potabilidade bacteriológica é determinada principalmente pela verificação da presença de bactérias do grupo coliforme (totais e fecais) indicadoras de poluição fecal, maior responsável pela transmissão de doenças infecciosas à população. O objetivo desta pesquisa foi verificar a eficácia dos processos de tratamento executados nas Estações de Tratamento de Água (ETA) de Araraquara, determinando as concentrações de bactérias coliformes totais e fecais, em
 cada etapa do processo de tratamento: água bruta, após floculação/decantação, filtração e cloração - relacionadas com a turbidez, avaliando se a água produzida está de acordo com os padrões do Ministério da Saúde e do Estado de São Paulo. O número mais provável (NMP/100mL) de bactérias coliformes totais e coliformes fecais foi determinado pela técnica das fermentações em tubos múltiplos, provas presuntiva e confirmatória. As análises foram realizadas mensalmente por um período de doze meses. Em todas as
 colheitas verificou-se que a água bruta apresentou grande quantidade de coliformes (NMP/100mL), daí a necessidade de tratamento e a importância fundamental que a fase de desinfecção tem para que a água chegue a população dentro dos padrões de qualidade. Concluíu-se que após a cloração ocorreu redução no número (NMP/100mL) de bactérias
 coliformes totais e fecais paralela à redução de turbidez e que a água produzida pelas ETAs atende aos padrões determinados pelo Ministério da Saúde e do Estado de São
 Paulo.

The Annual Bacterial Particle Concentration and Size Distribution in the Ambient Atmosphere in a Rural Area of the Willamette Valley, Oregon

Airborne bacterial samples were collected using wet cyclone and cascade impact samplers 2 to 3 times a week at 2 agricultural sites in the mid-Willamette River valley, near Corvallis, OR during 1997. The concentrations of total (TB), culturable (CB), and particulate-associated culturable (PACB) bacteria in the ambient atmosphere were measured using epifluorescence microscopic and culture methods. All three categories of airborne bacteria were found to have major concentration peaks in the summer (e.g., from June to September), especially in July and August. This may reflect the greater summer flux of bacteria from agricultural sources and activities and dry/dusty soil conditions. The PACB had several smaller peaks scattered in the winter and autumn. Size analysis of the PACB showed that the summer PACB peak was composed primarily of larger bacterial particles, whereas the smaller peaks in other seasons were composed primarily of smaller bacterial particles that occur during rainfall or storms events. The ...

Prolonged Intake of Fructo-Oligosaccharides Induces a Short-Term Elevation of Lactic Acid-Producing Bacteria and a Persistent Increase in Cecal Butyrate in Rats

While the prebiotic effects of fructo-oligosaccharides (FOS), short-chain polymers of fructose, have been thoroughly described after 2–3 wk of ingestion, effects after intake for several months are unknown. We tested the hypothesis that these effects would differ after ingestion for short and long periods in rats. Rats were fed a basal low-fiber diet (Basal) or the same diet containing 9 g/100 g of FOS for 2, 8 or 27 wk, and cecal contents were collected at the end of each time period. Cecal short-chain fatty acid concentration was higher in rats fed FOS than in those fed Basal, and this effect persisted over time: 83.8 ± 4.1 vs. 62.4 ± 6.5 μmol/g at 2 wk and 103.5 ± 5.8 vs. 73.2 ± 7.4 μmol/g at 27 wk (P < 0.05). The molar butyrate ratio was higher in rats fed FOS regardless of the time period (14.8 ± 0.6% vs. 6.7 ± 1.1% at 27 wk, P < 0.05). Lactate concentration in rats fed FOS was elevated after 2 wk and then decreased: 63.5 ± 21.6 μmol/g at 2 wk vs. 8.8 ± 3.3 μmol/g at 8 wk (P < 0.05). After 2 wk, FOS increased the concentrations of total lactic acid-producing bacteria, and Lactobacillus sp. (P < 0.05), without modifying total anaerobes. However, most of these effects were abolished after 8 and 27 wk of FOS consumption. In the long term, the FOS-induced increase in intestinal lactic acid-producing bacteria was lost, but the butyrogenic properties of FOS were maintained.

Bacterial populations contaminating the upper gut in patients with small intestinal bacterial overgrowth syndrome

OBJECTIVE: Small intestinal bacterial overgrowth syndrome (SIBOS) is characterized by an abnormally high bacterial population level in the upper gut, exceeding 10 5 organisms/ml (5 log colony-forming unit (CFU)/ml). To understand its origin and select an appropriate antibiotic treatment, we have analyzed the bacterial populations contaminating the upper gut in SIBOS patients. METHODS: Jejunal samples of 63 consecutive patients with diarrhea or malabsorption and conditions predisposing to SIBOS were cultured and antibiotic sensitivities determined. RESULTS: Concentrations of total, microaerophilic, and anaerobic bacteria were confirmed in 55 patients with SIBOS (mean ± SE) 7.6 ± 0.8, 7.4 ± 0.9, and 6.1 ± 0.7 log CFU/ml, respectively. Mean number of bacterial genera was 4.6 ± 0.8. The main bacteria recovered were (mean ± SE log CFU/ml) Streptococcus (71%; 6.4 ± 0.8), Escherichia coli (69%; 7.2 ± 0.9), Staphylococcus (25%; 6.2 ± 0.6), Micrococcus (22%; 6.0 ± 0.7), Klebsiella (20%; 7.1 ± 0.8), Proteus (11%; 6.1 ± 0.8) for microaerophilic bacteria, and Lactobacillus (75%; 6.1 ± 1.1), Bacteroides (29%; 6.9 ± 1.3), Clostridium (25%; 5.5 ± 1.0), Veillonella (25%; 5.3 ± 0.7), Fusobacterium (13%; 4.8 ± 0.5), and Peptostreptococcus (13%; 6.1 ± 0.7) for anaerobic bacteria. Amoxicillin–clavulanic acid and cefoxitin were efficient on >90% of strains. CONCLUSIONS: Contaminating flora isolated in SIBOS include commonly identified oropharyngeal and colonic flora, but these occur in SIBOS at different levels from those usually found in their original location. These data may hopefully serve as a starting point to further therapeutic controlled studies.

Bioaerosol Concentration at an Outdoor Composting Center

ABSTRACT Compost centers are one of many environments that produce airborne microorganisms. The objective of this study was to compare the bacterial, fungal, and acti-nomycete concentrations at the Norman, OK, compost center to background concentration of these same microorganisms. For this comparison, a modified Andersen Microbial Sampler was used. Sampling was performed at three sites at the outdoor compost center and at two background sites. The concentration of each microorganism was measured as total colony forming units per cubic meter (CFU/m3). The predominantly downwind compost center site had a 10-fold increase in all the microorganisms in comparison with the other sites (p < 0.05). The median concentrations (95% confidence interval) of total viable bacteria, Gram-negative bacteria, fungi, and actinomycetes at this site were 5059 (CI95= 4952-9600) CFU/m3, 2023 (CI95= 2586-6806) CFU/m3, 972 (CI95= 964-1943) CFU/m3, and 2159 (CI95= 1755-4190) CFU/m3, respectively.

Effects of temperature and ultraviolet radiation on microbial foodweb structure: potential responses to global change

Summary1. A series of growth experiments were conducted with natural plankton communities from a lake and river in northern Quebec, to evaluate the response of microbial foodweb structure to changes in ambient temperature and solar ultraviolet radiation (UVR).2. Bioassays were incubated for 6 days at two temperatures (10 and 20 °C) and three near‐surface irradiance conditions [photosynthetically active radiation (PAR) + UVA + UVB, PAR + UVA, and PAR only).3. The concentration of total bacteria showed no net response to temperature, but the percentage of actively respiring bacteria, as measured with the cellular redox probe5‐cyano‐2,3‐ditolyl tetrazolium chloride (CTC), was up to 57% higher at 20 °C relative to 10 °C. Chlorophyll a concentrations in the &lt; 2 μm size fraction also reacted strongly to temperature, with a net increase of up to 61% over the temperature range of 10–20 °C.4. The UVR effects were small or undetectable for most of the measured variables; however, the percentage of actively respiring bacteria was significantly inhibited in the presence of UVR at 20 °C, decreasing by 29–48% on day 6 in the lake experiments and by 59% on day 2 in one river experiment.5. The results show differential sensitivity to temperature among organisms of microbial communities in subarctic freshwaters, and a resilience by the majority of micro‐organisms to their present UVR conditions. Microbial foodwebs in northern freshwaters appear to be relatively unresponsive to short‐term (days) changes in UVR. However, the observed responses to temperature suggest that climate change could influence community structure, with warmer temperatures favouring picoplanktonic phototrophs and heterotrophs, and a shift in nanoplankton species composition and size structure.

Hygienic aspects of biowaste composting: airborne microbial concentrations as a function of feedstock, operation and season

In the present study, airborne concentrations of total bacteria, molds+yeasts as well as fecal coliforms and streptococci were measured at a composting plant as a function of key variables, including feedstock composition, operational procedures and season. The facility where the measurements were performed is a large (60 000 tonnes day-1), turned and aerated static pile composting installation for source-separated vegetable, fruit and garden waste (VFG) collected from households in a region of the northern part of Belgium.

Mode of action of yeast culture (YEA-SACC 1026) for stimulation of rumen fermentation in buffalo calves

The effect of daily supplementation of 5 g Saccharomyces cerevisiae yeast culture (YC, YEA-SACC 1026), 30 g NaHCO3, supernatant from 5 g YC (YCS), 5 g autoclaved YC (YCH) or 5 g γ-irradiated YC (YCR) to the diet of buffalo calves on rumen microbial populations and fermentation pattern was examined. Addition of 30 g NaHCO3 increased the rumen pH to the level observed with YC group. The pH and the concentrations of total, total viable and cellulolytic bacteria and total volatile fatty acids (VFA) were significantly higher while that of lactic acid, hexose-unit oligosaccharides and NH3-N were significantly lower in the rumen fluid of YC compared with the control group. The effect of NaHCO3 was 39·5 and 59·5% in decreasing the concentrations of lactic acid and hexose-unit oligosaccharides, 48·1, 47·2 and 45·5% in increasing the numbers of total, total viable and cellulolytic bacteria, 50·0 and 58·1% in increasing the concentrations of total VFA and protein and 51·3% in decreasing the concentration of NH3-N of YC. The corresponding values for YCR addition in the diet were 38·6, 45·7, 48·5, 44·4, 51·5, 39·1, 48·1 and 46·5%. The effect of YCS and YCH was only marginal, but conspicuous up to 2 h after feeding, in changing the above rumen variables when compared with the YC group. The results indicated that contribution of increase in pH in changing the rumen variables was approximately 50% of YC and almost all the stimulatory activity was associated with live yeast cells. Autoclaving of YC destroyed almost all and γ-irradiation of YC retained about 50% of stimulatory activity of YC. The effect of YC on rumen fermentation, which was maximum up to 2 to 4 h after feeding, decreased with time. © 1998 SCI.

The Development of Robust Methods for Measuring Concentrations and Emission Rates of Gaseous and Particulate Air Pollutants in Livestock Buildings

Abstract Air pollutants in livestock buildings may represent a risk to the health of both the housed livestock and of the stockmen. Moreover, when these air pollutants leave a building in its ventilation air, they may also represent a risk of pollution to the wider environment. A set of versatile and robust methods for quantifying pollutant emissions was therefore developed for common use during an extensive field survey of livestock buildings (329 sets of measurements) across four Northern European countries. Measurements were made, at seven different positions in each livestock building, of air temperature and relative humidity, and of the concentrations of carbon dioxide, ammonia, airborne dust (both inhalable and respirable), microorganisms and endotoxins. Concentrations of carbon dioxide were continuously measured by an infra-red analyzer while concentrations of ammonia were continuously measured by a chemiluminescence NO x analyzer preceded by a thermal converter. Mass concentrations of inhalable and respirable dust were measured by total filters and cyclone samplers, respectively, and the exposed filters were also assayed for endotoxins. Concentrations of airborne total bacteria, Gram-negative bacteria and total fungi were measured in some of the buildings using a novel automated slit sampler. The ventilation rate of each building was estimated by a balance method from the information on both its internal and external carbon dioxide concentrations, and hence the emission rates of the different aerial pollutants from each building were estimated. The results of applying the methods are reported and discussed in detail in later papers in the series, but as an example of the results obtained, a slurry-based sow unit, monitored over 24 h in wintertime, gave internal carbon dioxide and ammonia concentrations in the ranges 1180–3765 and 5·3–17·4 p.p.m., respectively, along with internal temperatures and relative humidities in the ranges 15·7–20·4°C and 34–69% respectively. Examples of the estimated emission rates from the sow unit, averaged over the 24 h period and corrected for background, were: ammonia 0·86 g NH 3 /h (hpu) (hpu=heat production unit), inhalable dust 0·19 g/h (hpu), respirable dust 0·02 g/h (hpu), and total bacteria 2·3 M(cfu)/(hpu) where cfu is colony-forming units.

Concentrations and Emissions of Airborne Endotoxins and Microorganisms in Livestock Buildings in Northern Europe

Abstract The concentration of airborne endotoxins and microorganisms in livestock buildings (cattle, pig, poultry) was surveyed in four European countries (England, The Netherlands, Denmark and Germany). Measurements were made during the day and night. The endotoxin concentrations were determined from dust samples separated into inhalable and respirable fractions. Airborne microorganisms were classified as total bacteria,Enterobacteriaceaeand total fungi. The lowest endotoxin concentrations were found in cattle houses. The highest concentrations of endotoxin were measured in poultry houses, especially percheries, with an overall mean of 692 and 49 ng/m3for inhalable and respirable fractions, respectively. Endotoxin concentration was usually higher in the day than at night. These concentrations give cause for concern for the health of stockmen working in such buildings. The corresponding mean emission rates from poultry houses were 678 and 43 μg/h (500kg) liveweight, respectively, 51 and 6 μg/h (500kg) liveweight from pig buildings and 9 and 1 μg/h (500kg) liveweight from cattle houses. A new automated bioaerosol sampler was developed, which allows remote, independent sampling of airborne microorganisms. Its principle of operation is similar to a slit sampler: airborne microbes are collected by impaction on an agar surface. Most measurements of airborne microorganisms were made in Germany. The indoor concentration of total bacteria was 6·43 log colony-forming units (cfu)/m3in broiler houses, 5·1 log cfu/m3in pig buildings and 4·3 log cfu/m3in cattle buildings. During the day, the overall concentration ofEnterobacteriaceaeranged between 3 and 4 log cfu/m3. The mean fungi concentration for cattle was 3·8, for pigs 3·7 and for poultry 4·0 log cfu/m3during the day. Slightly lower concentrations were measured at night. No significant correlation was found between the concentrations of endotoxin andEnterobacteriaceae. The highest emission rate of total bacteria and fungi was measured for broilers, i.e. 9·5 and 4·7 log cfu/h (500 kg) liveweight, respectively. Buildings for laying hens had the highest mean emission rate of 7·1 log cfu/h (500 kg) liveweight forEnterobacteriaceae.

Influence of weaning on colonic bifidobacteria and enterobacteria in breast-fed infants: A longitudinal study

Transversal studies suggested that breast-fed infant's colonic flora is dominated by bifidobacteria whereas enterobacteria were the predominant organisms in bottle-fed infants. However, little information is available concerning the modification of the colonic flora during the weaning period. The aim of the present work was to study the influence of weaning on colonic bifidobacteria and enterobacteria in breast-fed infants. Patients and methods: Eighteen healthy infants aged 2 to 22 weeks and exclusively breast-fed participated in this longitudinal study. Fecal samples were collected each 21 days under breast-feeding (breast-feeding period), partial breast-feeding (weaning period) and after total weaning (post-weaning period), and immediately analysed for total viable bacteria, bifidobacteria and enterobacteria. Results: expressed as mean [95% Confidence Interval] 1) Fecal concentrations of total viable bacteria, expressed as lOglo cells/g wet weight, increased between breast-feeding period and post-weaning period (10.1 [9.8 10.3] to 10.7 [10.4 11.0], p<0.05). 2) Proportions of bifidobacteria and enterobacteria, expressed as lOgl0 cells/101° total viable bacteria, were as follows :

Effect of ruminal cellulolytic bacterial concentrations on in situ digestion of forage cellulose.

To evaluate the effects of ruminal cellulolytic bacterial concentrations on in vivo cellulose digestion, varying percentages of flaked soybean hulls were substituted for orchardgrass hay in high-forage diets fed to sheep. In two experiments, total and cellulolytic ruminal bacterial concentrations were not affected by diet. No differences were found for in situ digestion of forage cellulose in the first experiment; however, in Exp. 2, ruminal pH and in situ cellulose digestion were lower (P<.01) with a 40% soybean hull diet. In Exp. 3 with four sheep, two diets were compared, one containing 19.6% cellulose from alfalfa meal and the other 64.3% purified wood cellulose. Ruminal pH was lower (P<.02), 9 and 24 h after feeding, for the high-cellulose diet. Total bacterial concentrations did not change with diet; however, the concentration of cellulolytic bacteria increased (P<.05) when the higher cellulose diet was fed. In situ cellulose digestion was not different between diets. In Exp. 4, 3% sodium bicarbonate was added to the high-cellulose diet, and it was fed twice a day. No differences were observed in pH between diets (P>.42). However, the concentration of total ruminal bacteria increased (P<.06), the concentration of cellulolytic bacteria increased (P<.03), and the percentage of cellulolytic bacteria increased (P<.04) when the buffered high-cellulose diet was fed. In situ digestion of alfalfa cellulose at 30 h was not different between diets (P>.60). These data indicate that the concentration of cellulolytic bacteria is not the limiting factor in the digestion of cellulose in the rumen.

Comparison of commonly used samplers with a novel bioaerosol sampler with automatic plate exchange

A newly designed automatic bioaerosol sampler (ABS) was commissioned for studies of microbial bioaerosols. The original feature of the ABS is the facility for unattended, microprocessor-controlled sampling with automatic replacement of the agar Petri dishes after each sample. The ABS was compared with a six-stage Andersen sampler, an all-glass impinger and a Casella slit sampler. The air in two cattle and two poultry livestock buildings was sampled for the concentration of total bacteria and total fungi including yeast cells. Slightly smaller concentrations of total bacteria and total fungi were measured with the automatic bioaerosol sampler than with the reference samplers. The automatic bioaerosol sampler correlated best with the Andersen sampler and its cutoff diameter was estimated to be about 1.5 μm. Overall, this new sampler was found to be a useful development in the technology of sampling airborne microbes.

Selective enrichment of bifidobacteria in the intestinal tract of broilers by thermally produced kestoses and effect on broiler performance

A series of kestose oligosaccharides have been produced from pyrolysis of sucrose and the effects of feeding these thermal kestoses on broiler performance and cecal microbial populations were evaluated. Eighty-four broiler chicks (day-old Hubbard x Hubbard) were fed either a nutritionally complete basal starter diet (control), the starter diet dressed with 8% of other sugars found in the thermal kestoses mixture (glucose, sucrose, and fructose), or the starter diet dressed with 10% crude thermal kestoses (2% kestoses, 8% other sugars) for a 4-wk period. Body weight and feed intake were measured weekly. After 4 wk the birds were killed, cecal contents were collected, and selected microbial populations were enumerated. Weight gains were 938, 968, and 989 g for control, other sugars, and thermal kestoses groups, respectively. There were no dietary effects on weight gain, feed conversion, or concentrations of total aerobic bacteria, coliforms, aerobically enumerated lactobacilli, total anaerobes, or clostridia. Cecal bifidobacterial concentrations were increased (P < 0.001) 24-fold in kestose-treated birds compared with controls, with bifidobacterial concentrations being 8.98, 9.09, and 10.36 log10 cfu/g cecal DM in birds fed the control, other sugars, and thermal kestoses diets, respectively. Anaerobically enumerated lactobacilli concentrations in kestose-treated birds were increased (P < 0.007) sevenfold compared with controls, with lactobacilli concentrations being 9.56, 9.53, and 10.36 log10 cfu/g cecal contents, respectively. Thermally produced kestoses altered intestinal bacterial populations in broilers and may have potential to enhance health and performance under the appropriate conditions.

Effect of Yeast Culture Supplement on Ruminal Microbial Populations and Metabolism in Buffalo Calves Fed a High Roughage Diet

The effect of Saccharomyces cerevisiae yeast culture (YC, Yea-Sacc 1026) as a supplement to the high-roughage diet of buffalo calves on the rumen microbial populations, fermentation pattern and in sacco dry matter disappearance of dietary constituents was examined. A control group was fed a diet consisting of, on a dry matter basis, 2·12 kg bajra (Pennisetum typhoides) hay and 0·45 kg groundnut cake per day per calf, while the treatment group had the same diet plus 5 g YC. After feeding for 6 weeks, inclusion of YC was stopped and both groups were given the control diet for 2 weeks. At week 4 the pH in the rumen fluid (RF) was significantly higher (P<0·05) up to 6 h post-feeding in the treatment group compared with the control group. The concentrations of total, total viable and cellulolytic bacteria were increased by 41·0 (P<0·05), 33·5 and 57·4% (P<0·01), respectively, with YC supplement. The concentration of total volatile fatty acids (P<0·05), particularly at 4 h post-feeding (P<0·01) and acetate (P<0·01) and acetate to propionate ratio (P<0·05) were higher in the treatment compared with the control group. On YC supplementation, the concentration of NH3-N was decreased (P<0·05) while that of TCA-precipitable protein in RF was marginally but non-significantly increased. Withdrawal of YC from the diet reversed these effects and the rumen variables returned to values close to control levels after 2 weeks. The in sacco dry matter disappearance of dietary components was higher in the treatment compared with the control group, particularly during the first 24 h of incubation. © 1997 SCI.

Effect of Yeast Culture Supplement on Ruminal Microbial Populations and Metabolism in Buffalo Calves Fed a High Roughage Diet

The effect of Saccharomyces cerevisiae yeast culture (YC, Yea-Sacc 1026) as a supplement to the high-roughage diet of buffalo calves on the rumen microbial populations, fermentation pattern and in sacco dry matter disappearance of dietary constituents was examined. A control group was fed a diet consisting of, on a dry matter basis, 2·12 kg bajra (Pennisetum typhoides) hay and 0·45 kg groundnut cake per day per calf, while the treatment group had the same diet plus 5 g YC. After feeding for 6 weeks, inclusion of YC was stopped and both groups were given the control diet for 2 weeks. At week 4 the pH in the rumen fluid (RF) was significantly higher (P<0·05) up to 6 h post-feeding in the treatment group compared with the control group. The concentrations of total, total viable and cellulolytic bacteria were increased by 41·0 (P<0·05), 33·5 and 57·4% (P<0·01), respectively, with YC supplement. The concentration of total volatile fatty acids (P<0·05), particularly at 4 h post-feeding (P<0·01) and acetate (P<0·01) and acetate to propionate ratio (P<0·05) were higher in the treatment compared with the control group. On YC supplementation, the concentration of NH3-N was decreased (P<0·05) while that of TCA-precipitable protein in RF was marginally but non-significantly increased. Withdrawal of YC from the diet reversed these effects and the rumen variables returned to values close to control levels after 2 weeks. The in sacco dry matter disappearance of dietary components was higher in the treatment compared with the control group, particularly during the first 24 h of incubation. © 1997 SCI.

Long-Term Improvements in Water Quality Due to Sewage Abatement in the Lower Hudson River

Long-trend trends in dissolved oxygen (DO) and total coliform bacteria concentrations are used to evaluate the impact of almost 60 yr of sewage abatement and treatment in the lower Hudson River near New York City. Although some water pollution control plants have been in operation in the region since the 1930s, the most significant abatement of untreated sewage in the lower Hudson River has occurred since the late 1970s, when most of the existing plants were upgraded to secondary treatment, and additional plants were constructed. From at least 1922 through the early 1960s, average summer DO percent saturation varied between 35% and 50% in surface waters and 25% and 40% in bottom waters. Beginning in the late 1970s, DO concentrations generally increased through the 1980s and especially into the 1990s, coinciding with the upgrading of the 7.4 m3 s−1 (170 million gallons per day, mgd) North River plant to secondary treatment in the spring of 1991. Average summer percent saturation in the early 1990s exceeded 80% in surface waters and 60% in bottom waters. In addition, summer DO minima have increased from less than 1.5 mg 1−1 in the early 1970s to greater than 3.0 mg 1−1 in the 1990s, and the duration of hypoxia during summer months has been reduced. Total coliforms also display strong declining trends from the 1970s into the 1990s, with declines attributed to plant upgrades, construction of two New York City plants (North River and Red Hook) in the mid 1980s, and improved operation of the sewer system.