Trypanosoma congolense: calf erythrocyte survival.

Hereford calves infected with Trypanosoma congolense developed an anemia which was most severe 10 weeks after infection when packed cell volumes (PCV) averaged 21.1 ± 2.5% (±2 SE) as compared to 33.1 ± 2.1% for controls. At the termination of the study, at 28 weeks postinfection PCVs of infected animals had risen to 27.5 ± 1.0% as compared to 34.0 ± 1.7% for controls. In parallel with PCVs the apparent half-lives of ⁵¹Cr-labeled erythrocytes were reduced as early as the first 2 weeks postinfection. The greatest difference in erythrocyte half-lives between infected and control animals was found during the fourth to sixth weeks of infection when volumes for infected animals averaged 128 ± 46 hr as compared to 321 ± 30 hr for controls. During this period the parasitemia was at its highest level. At 28 weeks postinfection the average apparent half-life of infected animals was 243 ± 43 hr compared with 304 ± 11 hr for controls. No differences were observed in gastrointestinal loss of ⁵¹Cr between infected and control animals; however, urinary excretion of isotope was greatly increased in infected animals when compared to controls. No significant changes in total blood volumes were observed between infected and control animals but total plasma volumes increased and total erythrocyte volumes decreased significantly in infected animals.     

Water potential changes in faecal matter and Escherichia coli survival

Aims: This study investigated the influence of a range of evaporation rates (2·0, 5·3 and 7·4 mm day⁻¹) on degradation of E. coli (ATCC Strain 25922) inoculated in canine faeces. Methods and Results: Experiments were carried out in an environmental chamber and a first order exponential decay function (Chick’s Law) was used to estimate degradation rates. We estimated die-off coefficients using linear regression. Die-off rates were −0·07, −0·22 and −0·23 h⁻¹, respectively, for evaporation rates of 2·0, 5·3 and 7·4 mm day⁻¹ (P = 0·000+, for each model). Nearly complete die-off was found within 15–60 h (7·4–2·0 mm day⁻¹ evaporation rates), which corresponds with a water potential of approximately −22·4 MPa. Conclusions: This study indicates that canine faeces need not be desiccated to achieve complete loss of indicator organisms. Water potential, which is a combination of osmotic and matric potential, is a key stress that increases as evaporation removes water from the faecal matrix and increases concentration of the remaining faecal solution. Evaporation may remove populations of indicator organisms in faeces relatively quickly, even though faeces are not completely dehydrated. Significance and Impact of the Study: This research may be used as the foundation for studies more closely resembling real-world evaporation conditions including diurnal fluctuations, rewetting and freezing.     

A new radiotracer technique involving 14C and 51Cr,for estimating the assimilation efficiencies of aquatic,primary consumers

Summary Gravimetric, radiotracer, and indicator methods currently available for estimating assimilation efficiencies, have been reviewed and their associated limitations have been discussed. It was concluded that the basic assumption implicit to gravimetric and indicator techniques, i.e. that all material contained within the faeces is derived from the food, does not generally hold. Radiotracer techniques are not based on this assumption but are time consuming. Consequently a new radiotracer technique analogous to indicator methods has been developed. In this technique the concentration of a non-absorbed indicator is expressed in terms of a radiotracer, ¹⁴C, which can be absorbed but which, at least initially, is only present in the food, rather than expressing it in terms of dry weight. ⁵¹Cr has been used as the nonabsorbed indicator.Use of these two isotopes in conjunction not only enables a distinction to be made between faecal material derived from food, and that derived from metabolic secretions but also facilitates estimation of assimilation efficiences fromsmall samples of faeces only. The new technique requires simply, measurement of the ratio ¹⁴C:⁵¹Cr in samples of both food and faeces.The applicability of conditions necessary for operation of the new technique has been tested on two species of freshwater gastropod, one feeding on epilithic algae, the other on bacteria, and its effectiveness has been tested by reference to results obtained from another, more conventional method involving ¹⁴C only.     

Identification and quantification of viable Bifidobacterium breve strain Yakult in human faeces by using strain-specific primers and propidium monoazide

Aims: To develop a quick and accurate PCR‐based method to evaluate viable Bifidobacterium breve strain Yakult (BbrY) in human faeces. Methods and Results: The number of BbrY in faeces was detected by using strain‐specific quantitative real‐time PCR (qPCR) derived from a randomly amplified polymorphic DNA analysis. And using propidium monoazide (PMA) treatment, which combined a DNA‐intercalating dye for covalently linking DNA in dead cells and photoactivation, only viable BbrY in the faeces highly and significantly correlated with the number of viable BbrY added to faecal samples within the range of 10⁵–10⁹ cells per g of faeces was enumerated. After 11 healthy subjects ingested 10·7 log CFU of BbrY daily for 10 days, 6·9 (±1·5) log CFU g^?1 [mean (±SD)] of BbrY was detected in faeces by using strain‐specific transgalactosylated oligosaccharide–carbenicillin (T‐CBPC) selective agar medium. Viable BbrY detected by qPCR with PMA treatment was 7·5 (±1·0) log cells per g and the total number (viable and dead) of BbrY detected by qPCR without PMA treatment was 8·1 (±0·8) log cells per g. Conclusions: Strain‐specific qPCR with PMA treatment evaluated viable BbrY in faeces quickly and accurately. Significance and Impact of the Study: Combination of strain‐specific qPCR and PMA treatment is useful for evaluating viable probiotics and its availability in humans.     

Evaluation of titanium dioxide and chromic oxide as digestibility markers in ponies fed alfalfa hay in relation to marker dosing frequency

In equines, Cr₂O₃ is widely accepted as an indigestible marker, but there are health concerns regarding the carcinogenic properties of Cr₂O₃. Recently, TiO₂ has been suggested to be an alternative digestibility marker in equines. However, a comparison between Cr₂O₃ and TiO₂ has not been made in equines. Six Welsh pony geldings (initial BW: 254±3 kg; 7 years of age) fed chopped alfalfa hay were used to evaluate the use of TiO₂ (Ti) and Cr₂O₃ (Cr) as markers for calculating apparent digestibility and to investigate the effect of frequency of marker administration on the measurement of digestibility values. Diets contained 4.65 kg dry matter (DM) chopped alfalfa hay supplemented with minerals, vitamins, TiO₂ (3.3 g Ti/day) and Cr₂O₃ (3.2 g Cr/day). Ponies were dosed with either 3.3 g Ti and 3.2 g Cr once daily (DF1) or with 1.65 g Ti and 1.60 g Cr twice daily (DF2). After adaptation to the diets and procedures for 14 days, voluntary voided faeces were collected quantitatively over 7 days and analysed for moisture, ash, Ti and Cr. Apparent total tract DM digestibility (DMD) and organic matter digestibility (OMD) were calculated using the total faecal collection (TFC) and marker method (Ti and Cr). The overall mean cumulative faecal recovery of Cr and Ti (as % of intake) were 102.0% and 96.6%, respectively. Mean daily faecal recoveries of Cr as well as of Ti were not different (P=0.323; P=0.808, respectively) between treatments. Overall daily faecal recovery of Cr differed (P=0.019) from 100% when the marker was dosed once daily, whereas overall daily faecal recovery was similar to 100% for both administration frequencies when Ti was used as a marker. For both markers, the coefficient of variation of the mean faecal marker recovery between horses was lower when the markers were administrated twice per day. Across treatments, cumulative DMD and OMD estimated with Ti were similar (P=0.345; P=0.418, respectively) compared with those values determined by TFC method. When Cr was used, the calculated cumulative DMD tended (P=0.097) to be greater compared with those estimated with TFC, and cumulative OMD values were overestimated (P=0.013). Orally supplemented Ti recovery in the faeces of ponies fed chopped alfalfa hay with Ti administered once or twice daily was close to 100%, making it the preferred marker for digestibility trials in equines.     

Shedding of feline lungworm larvae and their infectivity to snail intermediate hosts after anthelmintic treatment

Aelurostrongylus abstrusus and Troglostrongylus brevior are snail-transmitted helminths causing respiratory diseases in infected cats. The shedding of feline lungworm L1s and their infectivity to the snail intermediate host, after administration of anthelminthic products to cats, are poorly documented. To assess the efficacy of 8.3% fipronil, 10% (S)-methoprene, 0.4% eprinomectin and 8.3% praziquantel (i.e. eprinomectin formulation) and 10% imidacloprid/1% moxidectin (i.e. moxidectin formulation) against these nematodes and to determine the number of days post-treatment until viable L1s are released in the faeces, 384 animals were screened by faecal examination. Of the 54 positive animals (i.e., 14.1%; 7.3% A. abstrusus, 6.2% T. brevior and 0.5% coinfected), 36 were randomly allocated to four groups. Groups A and B were composed of cats positive for T. brevior and treated with the eprinomectin and with the moxidectin formulations, respectively, whereas cats in groups C and D were positive to A. abstrusus and treated with the eprinomectin and the moxidectin formulations, respectively. Prior to and every day after treatment, faecal samples were analysed by the Baermann technique and the number of larvae per gram of faeces determined, and again four weeks after treatment, to assess the efficacy of a single administration of the products. In addition, to evaluate the pre- and post-treatment infectivity of L1s to snail intermediate hosts, one/two snails per cat were infected with 100 L1s collected from the faeces of enrolled animals and then digested 28 days p.i. Based on L1s faecal counts, the efficacy of the eprinomectin and the moxidectin formulations at 28 days was 100% for both A. abstrusus and T. brevior, with a mean number of days of 7.9 ± 1.2 in group A, 7.8 ± 1.9 in B, 6.9 ± 1.6 in C and 8.9 ± 2.0 in D to become negative. Following the artificial digestion, active L3s of T. brevior and A. abstrusus were found in 160 (87.4%) experimentally infected snails. The results of this study demonstrate that a single administration of the two formulations is effective in the treatment of A. abstrusus and T. brevior infections and that during the post-treatment period live L1s are shed for up to 8.9 ± 2.0 days. L1s of both lungworm species released in the faeces after drug administration are still able to reach the infective larval stage in the infected snails. Hence, preventative measures after the treatment of infected animals should include keeping cats indoors and disposal of their faeces for approximately 10 days to avoid environmental contamination and infection of gastropod intermediate hosts.     

The effects of dietary additives on faecal levels of Lactobacillus spp., coliforms,and Escherichia coli,and faecal prevalence of Salmonella spp. and Campylobacter spp. in US production nursery swine1

Aims: In the United States, carbadox and copper sulfate are growth promoters commonly used in combination in nursery swine diets. Our aim was to determine how selected dietary additives affect selected bacterial populations and pathogens in nursery swine, and compare to larch extract, which contains potential antibacterial activities. Methods and Results: Piglets were weaned and sorted into one of the four treatments: (i) basal diet without antimicrobials; (ii) basal diet with carbadox + copper sulfate; (iii) basal diet + 1000 ppm larch extract; or (iv) basal diet + 2000 ppm larch extract. Diets were fed for a 4‐week period after weaning. In both trials, the carbadox + copper sulfate group consumed more feed over the 4‐week period relative to the other three diet groups (P < 0·05), but did not gain significantly more weight. Faecal shedding of Salmonella spp. was not affected by dietary supplement in either trial, but faecal shedding of Campylobacter spp. was the lowest for the carbadox + copper sulfate diet. In faecal samples collected at the end of each trial, Lactobacillus spp. cell counts for the basal and larch extract diets were nearly 1·0 log₁₀ g^?1 faeces greater (P < 0·05) than the carbadox + copper sulfate group, whereas the coliforms and Escherichia coli were nearly 1·0 log₁₀ g^?1 faeces lower (P < 0·05). Conclusions: Compared to basal fed animals, supplementation with carbadox + copper sulfate significantly altered faecal E. coli, coliform bacteria and Lactobacillus spp. Larch extract has no benefit up to 0·2% of diet in regard to pathogen shedding, whereas carbadox + copper sulfate decreased faecal shedding of Campylobacter spp. Significance and Impact of the Study: Current swine management practices in the United States may be beneficial to managing Campylobacter spp. shedding in nursery swine, but also result in significant changes in the resident gastrointestinal microflora.     

A dual marker technique to estimate individual feed intake in young pigs

Accurate estimation of individual feed intake (FI) of pigs could help better understand the variation in performance between individual animals. We studied dual marker methods to estimate individual FI in pigs. This method is based on the measurement of the ratio between two indigestible markers in faeces. Twelve 6.5-week-old individually housed male pigs were assigned to one of three oral dosing treatments supplying 180 mg of ytterbium chloride (YbCl₃)/day and 111 mg of dotriacontane (C32)/day as reference markers, either once (R1), three times (R3) or five times (R5) daily. Pigs were offered a diet containing 0.46 g/kg of chromium chloride (CrCl₃) and 0.15 g/kg of hexatriacontane (C36) as in-feed markers. The experiment lasted for 10 days: days ?5 to 0: adaptation; days 1–3: dosing of reference marker; days 2–4: total faecal collection. Spot faecal samples were taken on day 3 at 1200 h, 1700 h and on day 4 at 0700 h. Pigs were fed restrictedly three times daily, at 133.6 g/kg BW^0.60. Individual measured FI was recorded daily and was compared to predicted FI using the ratio of the dual marker pairs (Yb:Cr and C32:C36), both in total faecal collection and spot samples. Due to unequal variance, R1 pigs were omitted from the statistical treatment comparison. When using total faecal collection samples, the absolute prediction error (APE) (predicted FI minus measured FI) in R3 and R5 pigs was numerically lower than in R1 pigs, regardless of the marker pair used. The APE measured by C32:C36 was numerically lower than measured by Yb:Cr at all frequencies, and significantly (P = 0.039) in R3 pigs (C32:C36: 0.15 ± 0.02 kg/day; Yb:Cr: 0.29 ± 0.04 kg/day). This was related to a larger difference in faecal recovery between Yb and Cr compared with C32 and C36. Daily total faecal collection revealed that for R3 pigs, starting faecal collections 2 days after the onset of provision of the reference marker improved the APE when compared with starting after 1 day. When using C32:C36 to predict feed intake, pooled, but not single spot samples gave similar APEs compared with total faecal collections. Therefore, we recommend dosing the reference marker three times per day for 2 days on days 1 and 2, combined with pooled spot faecal sampling collected on days 3 and 4. In this way, absolute prediction errors of 10%-15% of simultaneously measured intakes of multiple nutrient resources in a complex housing system are feasible using the dual marker technique.     

Isolation of faecal coliform bacteria from the American alligator (Alligator mississippiensis)

Aims: To determine whether American alligators (Alligator mississippiensis) are an unrecognized poikilothermic source of faecal coliform and/or potential pathogenic bacteria in South Carolina’s coastal waters. Methods and Results: Bacteria from the cloaca of American alligators, as well as bacteria from surface water samples from their aquatic habitat, were isolated and identified. The predominant enteric bacteria identified from alligator samples using biochemical tests included Aeromonas hydrophila, Citrobacter braakii, Edwardsiella tarda, Escherichia coli, Enterobacter cloacae, Plesiomonas shigelloides and putative Salmonella, and these were similar to bacteria isolated from the surface waters in which the alligators inhabited. Based on most‐probable‐number enumeration estimates from captive alligator faeces, faecal coliform bacteria numbered 8·0 × 10⁹ g^?1 (wet weight) of alligator faecal material, a much higher concentration than many other documented endothermic animal sources. Conclusions: A prevalence of enteric bacteria, both faecal coliforms and potential pathogens, was observed in American alligators. The high faecal coliform bacterial density of alligator faeces may suggest that alligators are a potential source of bacterial contamination in South Carolina coastal waters. Significance and Impact of the Study: These findings help to increase our understanding of faecal coliform and potential pathogenic bacteria from poikilothermic reptilian sources, as there is the potential for these sources to raise bacterial water quality levels above regulatory thresholds.     

Early intervention with faecal microbiota transplantation: an effective means to improve growth performance and the intestinal development of suckling piglets

Recent studies indicate that early postnatal period is a critical window for gut microbiota manipulation to optimise the immunity and body growth. This study investigated the effects of maternal faecal microbiota orally administered to neonatal piglets after birth on growth performance, selected microbial populations, intestinal permeability and the development of intestinal mucosal immune system. In total, 12 litters of crossbred newborn piglets were selected in this study. Litter size was standardised to 10 piglets. On day 1, 10 piglets in each litter were randomly allotted to the faecal microbiota transplantation (FMT) and control groups. Piglets in the FMT group were orally administrated with 2ml faecal suspension of their nursing sow per day from the age of 1 to 3 days; piglets in the control group were treated with the same dose of a placebo (0.1M potassium phosphate buffer containing 10% glycerol (vol/vol)) inoculant. The experiment lasted 21 days. On days 7, 14 and 21, plasma and faecal samples were collected for the analysis of growth-related hormones and cytokines in plasma and lipocalin-2, secretory immunoglobulin A (sIgA), selected microbiota and short-chain fatty acids (SCFAs) in faeces. Faecal microbiota transplantation increased the average daily gain of piglets during week 3 and the whole experiment period. Compared with the control group, the FMT group had increased concentrations of plasma growth hormone and IGF-1 on days 14 and 21. Faecal microbiota transplantation also reduced the incidence of diarrhoea during weeks 1 and 3 and plasma concentrations of zonulin, endotoxin and diamine oxidase activities in piglets on days 7 and 14. The populations of Lactobacillus spp. and Faecalibacterium prausnitzii and the concentrations of faecal and plasma acetate, butyrate and total SCFAs in FMT group were higher than those in the control group on day 21. Moreover, the FMT piglets have higher concentrations of plasma transforming growth factor-β and immunoglobulin G, and faecal sIgA than the control piglets on day 21. These findings indicate that early intervention with maternal faecal microbiota improves growth performance, decreases intestinal permeability, stimulates sIgA secretion, and modulates gut microbiota composition and metabolism in suckling piglets.     

Fungal endophytes of a forage grass reduce faecal degradation rates

Mutualisms between fungal endophytes and forage grasses can exert broad-reaching effects on grassland communities and ecosystem processes. We hypothesised that endophytes of grasses would retard the process of faecal degradation since grazing animals consume primarily live plant material and excrete a large portion of the herbage they consume as faeces. We examined the degradation rates of faeces from sheep that had consumed pure swards of perennial ryegrass containing a range of unique strains (AR1, AR37, or Wild type) of the fungal endophyte, Neotyphodium lolii, or no endophyte. Ultimately, the presence of endophytes in perennial ryegrass resulted in slower faecal decay rates compared to the nil endophyte treatment, although only consistently for the C concentration decay rates that were approximately 2× to 4× slower in the endophyte-derived faecal matter. The decay rate of dry matter content was significantly slower (ca. 1.5×) in the novel endophyte-derived faeces (AR1 and AR37) compared to the nil endophyte-derived faeces. The N decay rates differed significantly only in the AR1 treatment that was approximately 4× slower than the nil endophyte group. The reduced decay rates are attributed to the presence of endophyte-derived alkaloids in the faeces, and a greater proportion of more easily degraded hemicellulose in faeces from sheep that consumed the endophyte-free grass. There were no significant differences in the faecal carbon and nitrogen decay rates among the three endophyte strain treatments. This suggests that all the strain-specific alkaloids might have similar effects, or that N. lolii has a general effect that is not strain-specific, such as altered fibre composition, as reported here. This is the first report of a fungal endophyte affecting the rate of faecal degradation, and the first report of the alkaloids peramine, lolitrem B and epoxy–janthitrems in faecal matter. This study shows that a common agronomic grass–endophyte mutualism can have effects on ecosystem processes that have not previously been considered.     

Use of a Bacteroides thetaiotaomicron-specific α-1-6, mannanase quantitative PCR to detect human faecal pollution in water

Aims: The aims of this work were to develop a quantitative test, based on Bacteroides thetaiotaomicron, for human faecal pollution in water and to evaluate test performance. Methods and Results: qPCR primers, based on the complete genomic sequence of B. thetaiotaomicron VPI 5482, were designed and tested. The single-copy putative mannanase homologue, α-1-6 mannanase, was selected as the particular target and sequences within this gene chosen as the qPCR primers by Blast search for specificity to B. thetaiotaomicron. The average concentration of B. thetaiotaomicron in human faeces was 1·39 × 10⁸ cells per gram faeces and the detection limit was 9·3 B. thetaiotaomicron copies per qPCR procedure. Comparison of B. thetaiotaomicron content in sewage vs pooled nonhuman faecal samples indicated that the current assay is specific for sewage. Conclusion: The subject assay is potentially useful for quantification of sewage pollution in water. Significance and Impact of the Study: Bacteroides-associated markers, proposed for faecal source tracking, have exclusively been based on gene sequences related to generally classified and uncultured bacteria. However, genes associated with host-microbe interaction have been suggested as more specific markers. The present assay targets such a gene of B. thetaiotaomicron which is considered to be a symbiont in the human gut.     

Observations on the epidemiology and interactions between myxomatosis, coccidiosis and helminth parasites in a wild rabbit population in Scotland

A study of the epidemiology of myxomatosis and the protozoan liver parasite, Eimeria stiedae, in a population of wild rabbits in Scotland from 1977 to 2010 is reported. Rabbits were collected on a monthly basis resulting in a total of 5,337 animals examined for the infections. The investigation showed that within any 1 year over the 34 years of the investigation the percentage of rabbits with myxomatosis varied between 0 and 24 %, while for E. stiedae infections fluctuated between 3 and 42 %. There were strong seasonal trends in the prevalence of myxomatosis with over 16 % being infected in September and October, and for E. stiedae, peaks of over 40 % of livers infected were recorded in July. From 2007 to 2010, faeces were also examined for coccidia oocysts and parasitic nematode eggs. Rabbits infected with the myxoma virus had mean oocyst counts of 73,665 per gram faeces, while rabbits not infected with the myxoma virus had counts of 31,952 oocysts per gram. Comparable figures for nematode faecal egg counts were 911 per gram in myxomatosis-infected animals and 427 per gram in uninfected animals. The elevated nematode faecal egg counts in rabbits with myxomatosis reflects increased worm burdens already reported, but the elevated counts of coccidial oocysts have not previously been reported. This would suggest that myxomatosis could compromise rabbit immunity to nematodes and coccidia.     

Trypanosoma congolense: Thrombocyte survival in infected steers

Charolais steers infected with Trypanosoma congolense developed a thrombocytopenia that was first demonstrated shortly before the onset of parasitemia. The thrombocyte count progressively decreased from a level of 6 × 10⁵/mm³ on the 3rd day postinfection to l × 10⁵/mm³, its most depressed level, on the 11th day postinfection. The mean of the thrombocyte level of five infected bovines at the time of thrombocyte survival analysis was 195.6 ± 83.5 × 10³(± 2 SE) as compared to 998 ± 245.9 × 10³ in the control group. In parallel with depressed thrombocyte levels, the mean of the apparent half-lives of ⁵¹Cr-labeled thrombocytes was 1.3 ± 0.5 days as compared to 3.7 ± 0.5 days in control animals. A similar survival was noted in the apparent half-lives of ⁵¹Cr-labeled autologous and heterologous thrombocytes transfused to normal recipients.     

A backflow of electrons around Photosystem II in Chlorella cells

A study was made with a modulated oxygen electrode of the effect of variations of oxygen concentration on photosynthetic oxygen evolution from algal cells. When Chlorella vulgaris is examined with a modulated 650 nm light at 22°C, both the oxygen yield and the phase lag between the modulated oxygen signal and the light modulations have virtually constant values between 800 and 120 ergs · cm^?1 · s^?1 if the bathing medium is in equilibrium with the air. Similar results are obtained at 32°C between 1600 and 120 ergs · cm^?2 · s^?1. Under anerobic conditions both the oxygen yield and the phase lag decrease if the light intensity is lowered below about 500 ergs · cm^?2 · s^?1 at 22°C or about 1000 ergs · cm^?2 · s^?1 at 32°C. A modulated 706 nm beam also gives rise to these phenomena but only at significantly lower rates of oxygen evolution. The cells of Anacystis nidulans and Porphyridium cruentum appear to react in the same way to anaerobic conditions as C. vulgaris. An examination of possible mechanisms to explain these results was performed using a computer simulation of photosynthetic electron transport. The simulation suggests that a backflow of electrons from a redox pool between the Photosystems to the rate-limiting reaction between Photosystem II and the water-splitting act can cause a decrease in oxygen yield and phase lag. If the pool between the Photosystems is in a very reduced state a significant cyclic flow is expected, whereas if the pool is largely oxidized little or no cyclic flow should occur. It is shown that the effects of 706 nm illumination and removal of oxygen can be interpreted in accordance with these proposals. Since a partial inhibition of oxygen evolution by 3-(3.4-dichlorophenyl)-1,1-dimethylurea (10^?8 M) magnifies the decreases in oxygen yield and phase lag, it is proposed that the pool which cycles back electrons is in front of the site of 3-(3,4-dichlorophenyl)-1,1-dimethylurea inhibition and is probably the initial electron acceptor pool after Photosystem II.     

Impact of early inoculation of probiotics to suckling piglets on postweaning diarrhoea – A challenge study with Enterotoxigenic E. Coli F18

Postweaning diarrhoea caused by Enterotoxigenic Escherichia coli (ETEC) is a threat to the pig industry. With an intensified focus on finding alternatives to the use of medical zinc oxide and antibiotics in newly weaned pigs, the objective of this study was to investigate the effect of early inoculation of probiotics to suckling piglets on subsequently ETEC faecal shedding and immune parameters in ETEC F18-challenged weaned piglets. Sixty pigs weaned on day 28 of age were assigned to three treatment groups: (i) Negative Control (non-challenged), (ii) Positive Control (challenged) and (iii) Probiotic (challenged and inoculated with a multi-species probiotic product during suckling). On days 1 and 2 postweaning, pigs in the Positive Control and Probiotic groups were challenged with 5 × 10⁸ colony-forming unit ETEC F18/pig/day, whereas pigs in the Negative Control group were provided with NaCl. Growth and diarrhoea incidence were not significantly affected by ETEC challenge or probiotic administration. ETEC F18 shedding and C-reactive protein concentration in plasma were significantly lower in the Negative Control group, confirming a successful challenge model. Pigs in the Probiotic group had a significantly reduced number of pigs shedding ETEC F18 and STb toxin in faeces compared with the Positive Control group. Probiotic application did not significantly impact the concentration of C-reactive protein, haptoglobin and cytokines in plasma nor haematology numbers. In conclusion, weaned pigs administered with a multi-species probiotic product early in life had a more rapid response towards the pathogen challenge and a faster clearance of ETEC compared with the Positive Control group. Administration of a multi-species probiotic to newborn piglets may thus promote resilience in the newly weaned pig. However, further studies with pigs subjected to a more severe pathogen challenge are needed to confirm these results and to investigate the mechanism of action of the probiotic intervention.     

Chromium effect on ROS generation and detoxification in pea (Pisum sativum) leaf chloroplasts

Pea plants were exposed to 0, 20, 50, and 100 µM chromium [Cr(VI)] to investigate oxidative stress in isolated chloroplasts. Leaf area and biomass accumulation were significantly reduced at higher Cr supply. Generation of superoxide, hydrogen peroxide, and ·OH radical generation was enhanced in the chloroplasts isolated from Cr-exposed pea plants. Cr(VI) significantly reduced F _v/F _m ratio of chlorophyll (Chl) fluorescence, Chl content, and whole chain electron transport rate. Superoxide dismutase (SOD) activity increased at lower Cr supply while it decreased at higher Cr supply. Ascorbate peroxidase (APX) was found to be most sensitive to Cr stress. Monodehydroascorbate reductase activity remained higher at 20 and 50 µM Cr but decreased at 100 µM Cr. Increased activities of dehydroascorbate reductase (DHAR) and glutathione reductase (GR) in the isolated chloroplasts were observed during the initial 3 days of Cr exposure of pea plants. Activities of DHAR and GR were increased up to day 3 only. Ascorbate and glutathione (GSH) pools showed similar decrease that was more evident in the GSH pool as the duration of Cr treatment increased. Observed changes in reactive oxygen species concentration, photosynthetic characteristics, and antioxidant system indicate that chloroplasts in Cr-exposed pea plants are an important target of oxidative stress.     

Effects of experimental infection with Eimeria bovis on the balance of sodium, potassium and water in calves

Balance trials were performed to investigate the effects of experimental Eimeria bovis coccidiosis on the metabolism of water, sodium and potassium in calves. Non-infected pair-fed controls and controls fed according to plan were included in the study to allow differentiation between the effects due to infection and due to changes in feed intake. Primary infection with 5 × 10⁴ (group A) or 1 × 10⁵ (group B) oocysts caused mild diarrhoea in three out of four group A calves and mild to severe haemorrhagic diarrhoea in all five group B calves. Losses of sodium and potassium via faeces tended to increase in the infected calves during patency and apparent digestibility (AD) of these minerals was comparably low. In the urine of the infected calves the Na/K-ratio decreased due to a reduced urinary excretion of sodium. The retention (RT) of sodium was particularly high in the calves that had received the higher oocyst dose. Potassium RT did not underlie significant changes during the course of coccidiosis. In the infected calves the plasma level of sodium was reduced transiently while the level of potassium remained fairly stable. Infections with the higher oocyst dose caused a distinct reduction of fluid excretion via urine which compensated for the increased faecal water losses during severe diarrhoea. Reinfection of the group A calves with 1 × 10⁵ oocysts did not cause any significant metabolic impairment. The results of this study indicate that although acute sublethal bovine coccidiosis alters electrolyte and water metabolism the overall balance of electrolytes and water is largely maintained by physiologic adaptation.     

A survey of enteric bacteria and protozoans in fresh bovine faeces on New Zealand dairy farms

Aims: To determine the counts and/or prevalence in fresh bovine faeces of Escherichia coli, enterococci, Campylobacter, Salmonella, shiga toxin‐producing E. coli (STEC), Giardia and Cryptosporidium, as inputs to numerical models designed to estimate microbial loadings on pasture grazed by cattle in New Zealand. Methods and Results: In each season over one year, samples of freshly deposited bovine faeces were collected from four New Zealand dairy farms (n = 155), and enumerated for E. coli, enterococci, Campylobacter, Giardia and Cryptosporidium. They were also tested for the presence of Salmonella and STEC. The overall median bacterial counts (g^?1 wet weight) were E. coli– 5·9 × 10⁶; enterococci – 1·3 × 10⁴; Campylobacter– 3·9 × 10⁵. All counts were highly variable within and between samplings, and few seasonal or regional patterns emerged. However, mean Campylobacter counts were consistently higher in spring. No Salmonella spp. was detected, and only two samples were positive for STEC. Cryptosporidium and Giardia were isolated from 5·2% and 4·5% of the samples, respectively, yielding low numbers of (oo)cysts (1–25 g^?1 and 1–17 g^?1, respectively). Conclusions: Fresh bovine faeces are a significant source of E. coli, enterococci and Campylobacter on New Zealand pastures, although numbers are likely to vary markedly between faecal samples. Significance and Impact of the Study: The study provides the first significant set of indicator and pathogen counts for one of the largest sources of faecal contamination of natural waters in New Zealand, and will be used to model these inputs.     

Faecal parameters as biomarkers of the equine hindgut microbial ecosystem under dietary change

Faeces could be used for evaluating the balance of the equine hindgut microbial ecosystem, which would offer a practical method for assessing gut health and how this relates to disease. However, previous studies concluded that faeces microbial ecosystem was not representative of the proximal hindgut (caecum and ventral colon). This study aimed to evaluate if variations of the faecal microbial ecosystem were similar to those observed in the proximal hindgut. Six horses, fistulated in the caecum and right ventral (RV) colon, were subjected to a gradual change of diet, from a 100% hay (high fibre) diet (2.2 DM kg/day per 100 kg BW) to a 57% hay+43% barley (high starch) diet (0.8 DM kg/day per 100 kg BW hay and 0.6 DM kg/day per 100 kg BW barley). The two diets were iso-energetic and fed over a 3-week trial period. Samples of digesta from the caecum, RV colon and faeces were collected two times on the 10th and 20th day of the trial, for each diet to assess the microbial ecosystem parameters by both classical culture technics and biochemical methods. The variations observed in the caecal and colonic bacterial composition (increase in total anaerobic, amylolytic and lactate-utilizing and decrease in cellulolytic bacteria concentrations) and microbial activity (changes in volatile fatty acids concentrations and increase in lactate concentrations) demonstrated that the hay+barley diet caused changes in the hindgut microbial ecosystem. Similar variations were observed in the faecal microbial ecosystem. Feeding the hay+barley diet resulted in higher concentrations of faecal lipopolysaccharides. The functional bacterial group concentrations (cellulolytics, amylolytics and lactate utilizers) were significantly correlated between caecum and faeces and between colon and faeces. From analyses of the metabolites produced from microbial activity, only valerate concentration in the caecum and the proportion of propionate were significantly correlated with the same parameters in the faeces. Results of the principal component analysis performed between all the caecal/faecal and colonic/faecal parameters revealed that the total anaerobic and cellulolytic bacteria concentrations, as well as valerate, l-lactate and lipopolysaccharide concentrations were strongly correlated with several microbial parameters in the caecum (P<0.027; r>|0.45|) and in the colon (P<0.013; r>|0.50|). This demonstrated that faecal samples and their bacterial analyses could be used to represent caecum and RV colon hindgut microbial ecosystem in terms of variations during a change from a high-fibre to a high-starch diet, and thus could be markers of particular interest to diagnostic proximal hindgut microbial disturbances.