Alexandra H.A. Dugdale

A mixture containing galactooligosaccharide, produced by the enzymic activity of Bifidobacterium bifidum, reduces Salmonella enterica serovar Typhimurium infection in mice

The prebiotic Bimuno is a mixture containing galactooligosaccharide, produced by the galactosyltransferase activity of Bifidobacterium bifidum NCIMB 41171 in the presence of lactose. Previous studies have implicated prebiotics in reducing infections by enteric pathogens, thus it was hypothesized that Bimuno may confer some protection in the murine host from Salmonella enterica serovar Typhimurium (S. Typhimurium) infection. In this study, infection caused by S. Typhimurium SL1344nal(r) in the presence or absence of Bimuno was assessed using tissue culture assays, a murine ligated ileal gut loop model and a murine oral challenge model. In tissue culture adherence and invasion assays with HT-29-16E cells, the presence of approximately 2 mM Bimuno significantly reduced the invasion of S. Typhimurium SL1344nal(r) (P<0.0001). In the murine ligated ileal gut loops, the presence of Bimuno prevented colonization and the associated pathology of S. Typhimurium. In the BALB/c mouse model, the oral delivery of Bimuno prior to challenge with S. Typhimurium resulted in significant reductions in colonization in the five organs sampled, with highly significant reductions being observed in the spleen at 72 and 96 h post-challenge (P=0.0002, <0.0001, respectively). Collectively, the results indicate that Bimuno significantly reduced the colonization and pathology associated with S. Typhimurium infection in a murine model system, possibly by reducing the invasion of the pathogen into host cells.

Weight loss resistance: A further consideration for the nutritional management of obese Equidae

Evidence-based, weight loss management advice is required to address equine obesity. Changes in body mass (BM), body condition score (BCS), heart (HG) and belly circumference (BG), direct (ultrasonographic) and indirect (D(2)O dilution, bioelectrical impedance analysis [BIA]) measures of body fat as well as indices of insulin resistance (IR) were monitored in 12 overweight (BCS ≥ 7/9) horses and ponies of mixed breed and gender for 16 weeks. Animals were randomly assigned to two groups (Group 1, n=6, BCS 7.6/9 ± 0.6, 489 ± 184.6 kg; Group 2, n=6, BCS 8.1/9 ± 0.6, 479 ± 191.5 kg). Daily dry matter intake (DMI) was restricted to 1.25% BM as one of two, near-isocaloric (DE ∼0.115 MJ/kg BM/day), forage-based diets (Group 1, 0.8% BM chaff-based feed: 0.45% BM hay; Group 2, 1.15% BM hay: 0.1% BM nutrient-balancer). Statistical modelling revealed considerable between-animal heterogeneity in proportional weight losses (0.16-0.55% of Week 1 BM weekly). The magnitude of weight loss resistance (WLR) or sensitivity to dietary restriction was independent of diet or any measured outset variable and was largely (65%) attributed to animal identity. Predicted rates of weight loss decreased over time. BCS and BIA were poor estimates of D(2)O-derived body fat%. Reciprocal changes in depths of retroperitoneal and subcutaneous adipose tissues were evident. Changes in BG were associated with losses in retroperitoneal fat and BM (r(2), 0.67 and 0.79). Indices of IR improved for 9/12 animals by Week 16. For obese animals, weight loss should be initiated by restricting forage DMI to 1.25% BM. Subsequent restriction to 1% BM may be warranted for WLR animals.

Purified galactooligosaccharide, derived from a mixture produced by the enzymic activity of Bifidobacterium bifidum, reduces Salmonella enterica serovar Typhimurium adhesion and invasion in vitro and in vivo.

The prebiotic Bimuno(®) is a mixture containing galactooligosaccharides (GOSs), produced by the galactosyltransferase activity of Bifidobacterium bifidum NCIMB 41171 using lactose as the substrate. Previous in vivo and in vitro studies demonstrating the efficacy of Bimuno(®) in reducing Salmonella enterica serovar Typhimurium (S. Typhimurium) colonization did not ascertain whether or not the protective effects could be attributed to the prebiotic component GOS. Here we wished to test the hypothesis that GOS, derived from Bimuno(®), may confer the direct anti-invasive and protective effects of Bimuno(®). In this study the efficacy of Bimuno(®), a basal solution of Bimuno(®) without GOS [which contained glucose, galactose, lactose, maltodextrin and gum arabic in the same relative proportions (w/w) as they are found in Bimuno(®)] and purified GOS to reduce S. Typhimurium adhesion and invasion was assessed using a series of in vitro and in vivo models. The novel use of three dimensionally cultured HT-29-16E cells to study prebiotics in vitro demonstrated that the presence of ∼ 5 mg Bimuno(®) ml(-1) or ∼ 2.5 mg GOS ml(-1) significantly reduced the invasion of S. Typhimurium (SL1344nal(r)) (P<0.0001). Furthermore, ∼ 2.5 mg GOS ml(-1) significantly reduced the adherence of S. Typhimurium (SL1344nal(r)) (P<0.0001). It was demonstrated that cells produced using this system formed multi-layered aggregates of cells that displayed excellent formation of brush borders and tight junctions. In the murine ligated ileal gut loops, the presence of Bimuno(®) or GOS prevented the adherence or invasion of S. Typhimurium to enterocytes, and thus reduced its associated pathology. This protection appeared to correlate with significant reductions in the neutral and acidic mucins detected in goblet cells, possibly as a consequence of stimulating the cells to secrete the mucin into the lumen. In all assays, Bimuno(®) without GOS conferred no such protection, indicating that the basal solution confers no protective effects against S. Typhimurium. Collectively, the studies presented here clearly indicate that the protective effects conferred by Bimuno(®) can be attributed to GOS.

Dietary restriction in combination with a nutraceutical supplement for the management of equine metabolic syndrome in horses

Few studies have examined the effect of dietary restriction in horses with equine metabolic syndrome (EMS). This study aimed to determine improvements in insulin sensitivity following dietary restriction for 6 weeks, and to determine if the improvement would be greater in horses receiving short-chain fructo-oligosaccharides (sc-FOS). Dietary management involved feeding grass hay, restricted to 1.25% of body mass (BM) as daily dry matter intake and soaked in cold water prior to feeding, with the addition of a vitamin and mineral nutraceutical supplement with or without the addition of sc-FOS (10 g/100 kg). Soaking the hay resulted in a significant reduction in non-structural carbohydrates (38%, P = 0.01), digestible energy (6.78%, P = 0.01) and water soluble minerals. Following 6 weeks of dietary restriction with soaked grass hay and nutraceutical supplement, horses lost an average of 6.8% BM and showed reductions in body condition score (BCS) and belly circumference. Sensitivity to insulin improved overall, as determined by the total insulin response during the combined glucose insulin test. The magnitude of improvement in insulin sensitivity was associated with the degree of insulin resistance recorded at outset, and the extent of overall losses in BM and BCS, but was independent of the addition of sc-FOS. The nutraceutical supplement was highly palatable and no adverse effects were noted. From the findings of this study a strict dietary program in combination with a specifically designed vitamin and mineral nutraceutical supplement can be recommended to obtain rapid improvements in BM, BCS and insulin sensitivity of animals presenting with EMS.

A comparison of acepromazine-buprenorphine and medetomidine-buprenorphine for preanesthetic medication of dogs

OBJECTIVE To assess sedative and cardiopulmonary effects of premedication with a medetomidine-buprenorphine or acepromazine-buprenorphine combination in dogs anesthetized with propofol and isoflurane. DESIGN Randomized controlled clinical trial. ANIMALS 90 dogs undergoing routine surgical and diagnostic procedures. PROCEDURES Dogs were randomly assigned to 1 of 3 premedication groups: group 1 (acepromazine, 0.03 mg/kg [0.014 mg/lb], IM; buprenorphine, 0.02 mg/kg [0.009 mg/lb], IM), 2 (medetomidine, 5 μg/kg [2.3 μg/lb], IM; buprenorphine, 0.02 mg/kg, IM), or 3 (medetomidine, 10 μg/kg [4.5 μg/lb], IM; buprenorphine, 0.02 mg/kg, IM). Anesthesia was induced with propofol and maintained with isoflurane in oxygen. Simple descriptive scores for sedation were assigned 15 minutes (groups 2 and 3) and 30 minutes (group 1) after premedication administration. Basic cardiopulmonary data were recorded throughout the anesthetic period. Times to recovery from anesthesia were recorded. RESULTS Sedation scores did not differ significantly among groups. Mean and diastolic blood pressures were significantly lower and heart rate was significantly higher in group 1 than in the other groups. Mean end-tidal partial pressure of CO(2) was significantly lower and respiratory rate was significantly higher in group 1 than in the other groups. There were no significant differences in anesthetic recovery times between groups. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that either acepromazine or medetomidine could be used in combination with buprenorphine for premedication of dogs anesthetized with propofol and isoflurane for routine surgical and diagnostic procedures. Arterial blood pressure was better maintained with the medetomidine-buprenorphine combinations, but tissue perfusion was not investigated.

Impact of water-soaking on the nutrient composition of UK hays

EQUINE metabolic syndrome (EMS), defined as obesity, insulin resistance and an increased risk of laminitis, is becoming increasingly recognised as an important condition with serious welfare implications (Frank and others 2010). Dietary restriction is critical for the management of EMS, and using a low starch and sugar content diet has been shown to improve insulin sensitivity in overweight and obese horses and ponies (Dugdale and others 2010, Argo and others 2012). Feeding hay with a non-structural carbohydrate (NSC) content of <10–12 per cent dry matter (DM), equivalent to approximately 8–10 per cent DM water-soluble carbohydrate (WSC), has been advised for EMS cases (Frank 2009, Frank and others 2010). Feeding hay with a low (4 per cent) or moderate (10 per cent) NSC content has been shown to induce lower insulinaemic and glycaemic responses compared with hay of high NSC content (17 per cent) (Borgia and others 2011). McGowan and others (2013) demonstrated that restricted daily energy provision in the form of soaked hay promoted weight loss and improved insulin sensitivity in horses and ponies with EMS. Soaking hay has been recommended as a practical method to reduce the caloric content of hay for the management of conditions such as EMS (Frank and others 2010). There is, however, limited evidence on the effect of soaking hay on its nutrient composition. Studies that have assessed the effects of soaking on the energy and nutrient composition of hay have been inconsistent and contradictory (Warr and Petch 1992, Cottrell and others …

Interaction of enterohemorrhagic Escherichia coli O157:H7 with mouse intestinal mucosa

In this study, we used mouse ileal loops to investigate the interaction of enterohemorrhagic Escherichia coli (EHEC) O157:H7 with the mouse intestinal mucosa. With a dose of 10(9) and 3 h incubation, EHEC O157 was detected in the lumen and to a lesser extent associated with the epithelium. Typical attaching and effacing (A/E) lesions were seen, albeit infrequently. While the effector protein Tir was essential for A/E lesion formation, the bacterial type III secretion system adaptor protein TccP was dispensable. These results suggest that A/E lesions on mouse intestinal mucosa can be formed independently of robust actin polymerization.

Investigating medetomidine-buprenorphine as preanaesthetic medication in cats.

OBJECTIVES The objective of this study was to investigate medetomidine-buprenorphine preanaesthetic medication in cats. METHODS Forty American Society of Anesthesiologists (ASA) I female cats were enrolled in this prospective, blinded, clinical study. Cats were randomised into one of four groups: group M30 were injected intramuscularly with 30 microg/kg medetomidine, groups M10+B, M30+B and M50+B received 10, 30 and 50 microg/kg of medetomidine, respectively, each in combination with 20 microg/kg buprenorphine. After 30 minutes, a sedation score was allocated. Anaesthesia was induced using intravenous propofol and maintained using isoflurane in oxygen, while cats underwent ovariohysterectomy. Heart rate, respiratory rate, end-tidal carbon dioxide tension and oxygen saturation of haemoglobin were recorded. Atipamezole was administered intramuscularly at volatile agent discontinuation. Time taken to lift their head, sit in sternal and stand were recorded along with quality of recovery. RESULTS M30+B cats required significantly less isoflurane compared with M30 cats. Heart rate and oxygen saturation of haemoglobin were significantly lower in M50+B cats than in M30 cats. All M+B groups experienced significantly better recoveries compared with the medetomidine only M30 control group. CLINICAL SIGNIFICANCE The addition of buprenorphine to medetomidine preanaesthetic medication in cats reduces volatile agent vaporiser setting and improves the quality of recovery from anaesthesia.

Use of rocuronium administered by continuous infusion in dogs

OBJECTIVE A clinical trial to determine whether continuous infusion administration technique was suitable for maintaining neuromuscular blockade with rocuronium bromide in dogs. ANIMALS Twenty-two dogs, 10 males and 12 females, median age 2 years 4 months, median weight 32 kg undergoing elective surgical procedures under general anaesthesia: ASA classification I or II. MATERIALS AND METHODS After induction of anaesthesia, neuromuscular function was evaluated using train-of-four (TOF) stimulation of the dorsal buccal branch of the facial nerve. A bolus dose of 0.5 mg kg-1 rocuronium was administered intravenously and an infusion of 0.2 mg kg-1 hour-1 was started immediately. Neuromuscular blockade was assessed visually by counting the number of twitches observed during TOF stimulation repeated at 10-second intervals. RESULTS The bolus dose of rocuronium abolished the response to TOF stimulation in 21 of the 22 dogs. The median onset time of neuromuscular blockade (complete loss of all four twitches) was 82 seconds (range 38-184 seconds). Median infusion duration was 76 minutes (range 20.3-146 minutes). CONCLUSIONS AND CLINICAL RELEVANCE This protocol of rocuronium administration was considered to be effective in dogs. Constant infusion of rocuronium is easily applicable to clinical practice and further work is required on infusion titration.

The clinical use of the neuromuscular blocking agent rocuronium in dogs

OBJECTIVE The aim of this study was to characterize the onset and duration of action of the aminosteroid muscle relaxant rocuronium in dogs under clinical conditions. STUDY DESIGN Prospective single dose trial. ANIMALS Twenty-three dogs aged between 6 months and 12 years, weighing between 5.5 and 61.5 kg admitted to the University of Liverpool Small Animal Hospital between January and March 2000, and undergoing elective surgical procedures under general anaesthesia. MATERIALS AND METHODS Following induction of general anaesthesia, neuromuscular function was evaluated using train-of-four (TOF) stimulation. An initial dose of 0.4 mg kg-1 rocuronium was administered intravenously (IV) and neuromuscular blockade was monitored by visually assessing the number of responses (twitches) to TOF stimulation (train-of-four count: TOFC). Incremental doses of 0.16 mg kg-1 rocuronium were administered as indicated, when at least two twitches of the TOFC had returned. RESULTS Rocuronium (0.4 mg kg-1) abolished all responses to TOF stimulation in all dogs. The mean time to onset of neuromuscular blockade (complete abolition of all twitches) was 98 ± 52 seconds. Neuromuscular blockade (absence of all twitches to return of all four) lasted 32.3 ± 8.2 minutes. Incremental doses of 0.16 mg kg-1 had a mean duration of action of 20.8 ± 4.9 minutes and up to seven increments were shown to be noncumulative. The effects of rocuronium were readily antagonized with neostigmine and atropine. Small transient increases in arterial blood pressure, which occurred in three dogs after the administration of rocuronium, were the only cardiovascular side-effects observed. CONCLUSIONS Rocuronium is an effective nondepolarizing neuromuscular blocking agent in the dog, with a rapid onset of neuromuscular block after intravenous administration and an intermediate duration of action. CLINICAL RELEVANCE Rocuronium produced a neuromuscular block with similar characteristics to those obtained with vecuronium, thus apparently offering little advantage over vecuronium. However, its availability in aqueous solution and a longer shelf-life increases convenience.