The impact of different levels of functional oil supplementation in combination with salinomycin on growth performance and intestinal microbiota of broilers undergoing Eimeria challenge: An analysis of dynamics.

The effect of salinomycin sodium alone and in combination with functional oils on performance and microbiota of broiler infected Eimeria were evaluated. 512 broilers were randomly assigned to 4 treatments (8 replicates, 16 birds/pen): a Control group (any additives); Ionophore group: salinomycin supplementation at 66 ppm (SS66); Ionophore +0.075% Functional oil (FO) group (SS66 + FO supplementation at 750 ppm); and Ionophore +0.10% FO group (SS66 + FO supplementation at 1000 ppm). At 14 days of age, birds were gavaged with 1 mL of a saline solution containing sporulated oocysts of E. tenella, E. acervulina and E. maxima. Performance indices were measured weekly. At 28 days, intestinal content was collected for microbiota analysis. Broilers of Control group presented the worst performance indices. Broilers of Ionophore + FO (0.075% and 0.10%) groups exhibited a higher BW at 28 days of age. The supplementation of Ionophore +0.075% FO resulted in a higher relative proportion of Firmicutes and a lower proportion of Actinobacteria in the ileum-jejunum. Lactobacillaceae was the dominant family in the jejunal, and ileal microbiotas of broilers fed diets supplemented with Ionophore, Ionophore +0.075% FO and Ionophore +0.10% FO. The supplementation of ionophore yielded higher numbers of Lactobacillaceae, Enterobactereaceae and Cloritridiaceae in the cecal. Ionophore associated with FO controlled the Lactobacillaceae, Enterobactereaceae and Cloritridiaceae families present in the cecum. Therefore, the combination of salinomycin with functional oil showed synergistic effect on performance and modulation of intestinal microbiota of broilers challenged with Eimeria.

The LC-MS/MS-Based Measurement of Isopimaric Acid in Rat Plasma and Application of Pharmacokinetics.

Isopimaric acid (IPA) exhibits a diverse array of pharmacological activities, having been shown to function as an antihypertensive, antitumor, antibacterial, and hypocholesterolemic agent. However, few studies of the pharmacokinetics of IPA have been performed to date, and such analyses are essential to explore the in vivo mechanisms governing the biological activity of this compound. As such, we herein designed a selective LC-MS approach capable of quantifying serum IPA levels in model rats using an Agilent HC-C18 column (250 mm × 4.6 mm, 5 µm) via isocratic elution with a mobile phase composed of methanol 0.5% formic acid (91 : 9, v/v) at a 1 mL/min flow rate. Ion monitoring at m/z 301.2 [M-H]- was used to quantify IPA levels in plasma samples from these rats, while internal standard (IS) levels were assessed at m/z 455.3 [M-H]-. After validation, this approach was employed to conduct a pharmacokinetic analysis of rats administered IPA via the oral (p.o. 50, 100, or 200 mg/kg) and intravenous (i.v. 5 mg/kg) routes. Analyses of noncompartmental pharmacokinetic parameters revealed that IPA underwent secondary absorption following oral administration to these animals, with the two tested oral doses (50 and 100 mg/kg) being associated with respective absolute bioavailability values of 11.9% and 17.5%. In summary, this study may provide a foundation for future efforts to explore the mechanistic basis for the pharmacological activity of IPA, offering insights to guide its subsequent clinical utilization.

An observational cohort study on antimicrobial usage on dairy farms in Quebec, Canada.

Quantification of antimicrobial usage (AMU) is crucial to measure the effect of intervention programs, to determine associations between usage and resistance, to compare populations, and for benchmarking purposes. The primary objective of the study was to describe quantitatively the AMU on Quebec dairy farms over 1 yr: (1) the total AMU, (2) the AMU per administration route (intramammary, injectable, oral, intrauterine), and (3) the AMU per antimicrobial class and according to the categorizations of Health Canada and the World Health Organization. The secondary objective was to assess the effect of several characteristics (herd size, level of milk production, and incidence rate of common infectious diseases) on AMU rate. The AMU data were obtained for 101 dairy farms randomly selected in 3 important Quebec dairy regions by collecting and recording all empty drug packaging and invoices for medicated feed (spring 2017 to spring 2018). The AMU rate was reported in number of Canadian defined course doses for cattle per 100 cow-years. The average herd size was 67 cows per farm, and 2/101 farms were certified organic. Overall, an estimated mean of 537 Canadian defined course doses for cattle/100 cow-years was observed. The intramammary route during lactation was the most frequently observed, followed, in decreasing order of usage, by oral route in the feed, intramammary route at drying-off, and injectable route. Oral (other than in animal feed) and intrauterine formulations were infrequently collected from the garbage cans. The 5 most frequently observed antimicrobial classes were, by decreasing order of usage, ionophores, penicillins, aminocoumarins, aminoglycosides, and polymyxins. Highest priority critically important antimicrobials as defined by the World Health Organization were mainly collected from intramammary formulations during lactation followed by injectable and drying-off intramammary formulations. The herd size was positively associated with the total AMU rate but not with the usage rate of highest priority critically important antimicrobials. Incidence of diseases along with preventive use of antimicrobials (drying-off and medicated feed with antimicrobials) explained 48% of the variance in total AMU rate.

Salinomycin inhibits proliferative vitreoretinopathy formation in a mouse model.

Proliferative vitreoretinopathy (PVR) is a progressive disease that develops in a subset of patients who undergo surgery for retinal detachment repair, and results in significant vision loss. PVR is characterized by the migration of retinal pigment epithelial (RPE) cells into the vitreous cavity, where they undergo epithelial-to-mesenchymal transition and form contractile membranes within the vitreous and along the retina, resulting in recurrent retinal detachments. Currently, surgical intervention is the only treatment for PVR and there are no pharmacological agents that effectively inhibit or prevent PVR formation. Here, we show that a single intravitreal injection of the polyether ionophore salinomycin (SNC) effectively inhibits the formation of PVR in a mouse model with no evidence of retinal toxicity. After 4 weeks, fundus photography and optical coherence tomography (OCT) demonstrated development of mean PVR grade of 3.5 (SD: 1.3) in mouse eyes injected with RPE cells/DMSO (vehicle), compared to mean PVR grade of 1.6 (SD: 1.3) in eyes injected with RPE cells/SNC (p = 0.001). Additionally, immunohistochemistry analysis showed RPE cells/SNC treatment reduced both fibrotic (αSMA, FN1, Vim) and inflammatory (GFAP, CD3, CD20) markers compared to control RPE cells/DMSO treatment. Finally, qPCR analysis confirmed that Tgfß, Tnfα, Mcp1 (inflammatory/cytokine markers), and Fn1, Col1a1 and Acta2 (fibrotic markers) were significantly attenuated in the RPE cells/SNC group compared to RPE/DMSO control. These results suggest that SNC is a potential pharmacologic agent for the prevention of PVR in humans and warrants further investigation.

Ionophore Use and Toxicosis in Cattle.

Ionophores are a commonly used feed additive for animals and when used properly are safe. When feed mis-mixing occurs and an elevated dose of ionophore is given, a toxicosis can develop. Myocardial and skeletal muscles are the targets of a toxicosis. In many species there is a delay from the time of ingestion of a toxic dose in feed to when clinical signs occur. This makes it difficult to collect the feed in question that was at an elevated concentration. Cardiac troponins in serum can be used to make a diagnosis of an ionophore toxicosis.

A zwitterionic near-infrared fluorophore for real-time ureter identification during laparoscopic abdominopelvic surgery.

Iatrogenic injury of the ureters is a feared complication of abdominal surgery. Zwitterionic near-infrared fluorophores are molecules with geometrically-balanced, electrically-neutral surface charge, which leads to renal-exclusive clearance and ultralow non-specific background binding. Such molecules could solve the ureter mapping problem by providing real-time anatomic and functional imaging, even through intact peritoneum. Here we present the first-in-human experience of this chemical class, as well as the efficacy study in patients undergoing laparoscopic abdominopelvic surgery. The zwitterionic near-infrared fluorophore ZW800-1 is safe, has pharmacokinetic properties consistent with an ideal blood pool agent, and rapid elimination into urine after a single low-dose intravenous injection. Visualization of structure and function of the ureters starts within minutes after ZW800-1 injection and lasts several hours. Zwitterionic near-infrared fluorophores add value during laparoscopic abdominopelvic surgeries and could potentially decrease iatrogenic urethral injury. Moreover, ZW800-1 is engineered for one-step covalent conjugatability, creating possibilities for developing novel targeted ligands.

PIKfyve accelerates phagosome acidification through activation of TRPML1 while arrests aberrant vacuolation independent of the Ca2+ channel.

PIKfyve phosphorylates PtdIns(3)P to PtdIns(3, 5)P2. One of the best characterized effector downstream of PtdIns(3, 5)P2 is a lysosomal Ca2+ channel, TRPML1. Although it has been reported that TRPML1 is involved in phagosome-lysosome fusion, the relevance of the Ca2+ channel in phagosome acidification has been denied. In this article, however, we demonstrated that the phagosome acidification was dependent on TRPML1. Based on the classical idea that Fluorescein isothiocyanate (FITC)-fluorescence is highly sensitive to acidic pH, we could estimate the phagosome acidification by time laps imaging. FITC-zymosan fluorescence that was engulfed by macrophages, decreased immediately after the uptake while the extinction of FITC-zymosan fluorescence was delayed in PIKfyve-deficient cells. The acidification arrest was completely rescued in the presence of Ca2+ ionophore A23187. Cells treated with a PIKfyve inhibitor, apilimod, also showed delayed phagosome acidification but were rescued by the overexpression of TRPML1. Additionally, TRPML1 agonist, ML-SA1 was effective to acidify the phagosome in PIKfyve-deficient cells. Another phenotype observed in PIKfyve-deficient cells is vacuole formation. Unexpectedly, enlarged vacuole formation in PIKfyve-deficient cells was not rescued by Ca2+ or over expression of TRPML1. It is likely that the acidification and vacuolation arrest is bifurcating downstream of PIKfyve.

Manganese-52: applications in cell radiolabelling and liposomal nanomedicine PET imaging using oxine (8-hydroxyquinoline) as an ionophore.

The ionophore 8-hydroxyquinoline (oxine) has been used to radiolabel cells and liposomal medicines with 111In and, more recently, 89Zr, for medical nuclear imaging applications. Oxine has also shown promising ionophore activity for the positron-emitting radionuclide 52Mn that should allow imaging of labelled cells and nanomedicines for long periods of time (>14 days). However, to date, the radiometal complex formed and its full labelling capabilities have not been fully characterised. Here, we provide supporting evidence of the formation of [52Mn]Mn(oxinate)2 as the metastable complex responsible for its ionophore activity. The cell labelling properties of [52Mn]Mn(oxinate)2 were investigated with various cell lines. The liposomal nanomedicine, DOXIL® (Caelyx) was also labelled with [52Mn]Mn(oxinate)2 and imaged in vivo using PET imaging. [52Mn]Mn(oxinate)2 was able to label various cell lines with moderate efficiency (15-53%), however low cellular retention of 52Mn (21-25% after 24 h) was observed which was shown not to be due to cell death. PET imaging of [52Mn]Mn-DOXIL at 1 h and 24 h post-injection showed the expected pharmacokinetics and biodistribution of this stealth liposome, but at 72 h post-injection showed a profile matching that of free 52Mn, consistent with drug release. We conclude that oxine is an effective ionophore for 52Mn, but high cellular efflux of the isotope limits its use for prolonged cell tracking. [52Mn]Mn(oxinate)2 is effective for labelling and tracking DOXIL in vivo. The release of free radionuclide after liposome extravasation could provide a non-invasive method to monitor drug release in vivo.

Effects on health, performance, and tissue residues of the ionophore antibiotic salinomycin in finishing broilers (21 to 38 d).

A study was conducted to evaluate the effects of feeding salinomycin at the recommended prophylactic level, and at 2 and 3 times this level, to finishing male broilers (d 21 to 38). Four treatment groups were given the experimental diets containing 0, 60, 120, or 180 parts per million (ppm) salinomycin from d 21 to 38. Performance, relative organ weights, selected serum enzymes, and salinomycin residues in liver, muscle, and serum were determined. Salinomycin supplementation had no effect on body weight, feed intake, or feed conversion, and caused no overt signs of toxicity. After a week of being fed the salinomycin diets, the serum activity of aspartate aminotransferase was significantly increased in chickens fed 180 ppm compared with controls. These birds also showed microscopic lesions in breast and thigh muscles, but not in cardiac muscle. Salinomycin residues were not detected by high-performance liquid chromatography coupled to tandem mass spectrometry in liver or muscle samples from the birds fed 0, 60, or 120 ppm salinomycin. However, chickens fed 180 ppm salinomycin had detectable levels in liver and muscle above the maximum residue level of 5 µg/kg established by the European Union. All birds fed salinomycin had salinomycin in their sera with levels ranging from N.D. (not detected) in the controls to 24.4 ± 7.9, 61.4 ± 18.9, and 94.5 ± 9.1 µg/L for salinomycin dietary levels of 60, 120, and 180 ppm, respectively. Serum salinomycin concentration was linearly related with salinomycin content in feed (y = 0.584x - 10, r2 = 0.999). The results showed that even at 3 times the prophylactic level, salinomycin does not induce clinical toxicosis or mortality. No salinomycin residues were found in edible tissues at the recommended dietary level or at 2 times this level. However, salinomycin was detected in serum regardless of the dietary level. A simple method for salinomycin determination in serum is described which can be used as a marker of exposure and/or to predict levels in the diet.

Effects of rotating antibiotic and ionophore feed additives on volatile fatty acid production, potential for methane production, and microbial populations of steers consuming a moderate-forage diet.

Ionophores and antibiotics have been shown to decrease ruminal methanogenesis both in vitro and in vivo but have shown little evidence toward a sustainable means of mitigation. Feed additive rotation was proposed and investigated for methane, VFA, and microbial population response. In the present study, cannulated steers ( = 12) were fed a moderate-forage basal diet in a Calan gate facility for 13 wk. In addition to the basal diet, steers were randomly assigned to 1 of 6 treatments: 1) control, no additive; 2) bambermycin, 20 mg bambermycin/d; 3) monensin, 200 mg monensin/d; 4) the basal diet + weekly rotation of bambermycin and monensin treatments (B7M); 5) the basal diet + rotation of bambermycin and monensin treatments every 14 d (B14M); and 6) the basal diet + rotation of bambermycin and monensin treatments every 21 d (B21M). Steers were blocked by weight in a randomized complete block design where the week was the repeated measure. Rumen fluid was collected weekly for analysis ( = 13), and results were normalized according to individual OM intake (OMI; kg/d). Potential activity of methane production was not significantly different among treatments ( > 0.05). However, treatment tended to affect the CH-to-propionate ratio ( = 0.0565), which was highest in the control and lowest in the monensin, B21M, and B14M treatments (0.42 vs. 0.36, 0.36, and 0.33, respectively). The CH:propionate ratio was lowest in wk 2 and 3 ( < 0.05) but the ratio in wk 4 to 12 was not different from the ratio in wk 0. Week also affected total VFA, with total VFA peaking at wk 3 and plummeting at wk 4 (4.02 vs. 2.86 m/kg OMI; < 0.05). A significant treatment × week interaction was observed for the acetate-to-propionate (A:P) ratio, where bambermycin- and rotationally fed steers did not have a reduced A:P ratio compared with monensin-fed steers throughout the feeding period ( < 0.0001). Microbial analysis revealed significant shifts, but several predominant classes showed adaptation between 4 and 6 wk after additive initiation. There was no significant evidence to suggest that rotations of monensin and bambermycin provided additional benefits to steers consuming a moderate-forage diet at the microbial/animal and environmental level versus those continuously fed.

Performance of beef heifers supplemented with sodium lasalocid.

This study was conducted on 78 13-month-old crossbred beef heifers that weighed 215 kg in Southern Rio Grande do Sul (RS) State, Brazil. We evaluated the performance of beef heifers that were reared in a pasture system that received a mineral supplement energy-type protein with added sodium lasalocid (LAS). The heifers were randomly and uniformly divided into 2 groups, with 39 animals in each group. One group of animals received a mineral supplement energy-type protein without sodium lasalocid (CON), and the other group received a mineral supplement energy-type protein with added LAS. The mean feed intake, the body weight (BW), the average daily gain (ADG), the body condition score (BCS), and ovarian cyclicity were recorded, and economic parameters were calculated. No differences in supplement intake were observed between the groups, which ensures adequate intake of the other components of the mineral mixture, which are part of the nutritional requirements for the production process. Similarly, no difference in the ADG was observed between treatments. We observed that the heifers in the LAS group had a higher BW gain (51 kg) that the CON heifers (40 kg; P < 0.05). In addition, LAS-supplemented heifers had a higher BCS (3.53) than CON heifers (3.38) at the end of the experiment (P < 0.05). The heifers supplemented with LAS had a higher profitability than the CON heifers, even with the higher cost of the supplement containing LAS; this effect was due to the higher live BW at the end of the study. We concluded that the administration of a mineral supplement energy-type protein with added LAS has beneficial effects on beef heifers in terms of production and economic feasibility.

Triggering of Suicidal Erythrocyte Death by the Antibiotic Ionophore Nigericin.

The K(+),H(+) ionophore and antibiotic nigericin has been shown to trigger apoptosis and is thus considered for the treatment of malignancy. Cellular mechanisms involved include induction of oxidative stress, which is known to activate erythrocytic Ca(2+)-permeable unselective cation channels leading to Ca(2+) entry, increase in cytosolic Ca(2+) activity ([Ca(2+)]i) and subsequent stimulation of eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. This study explored whether and how nigericin induces eryptosis. Phosphatidylserine exposure at the cell surface was estimated from annexin V binding, cell volume from forward scatter, [Ca(2+)]i from Fluo3 fluorescence, pHi from BCECF fluorescence, ceramide abundance utilizing antibodies and reactive oxygen species (ROS) formation from DCFDA-dependent fluorescence. A 48-hr exposure of human erythrocytes to nigericin significantly increased the percentage of annexin-V-binding cells (0.1-10 nM), significantly decreased forward scatter (0.1-1 nM), significantly decreased cytosolic pH (0.1-1 nM) and significantly increased Fluo3 fluorescence (0.1-10 nM). Nigericin (1 nM) slightly, but significantly, increased ROS, but did not significantly modify ceramide abundance. The effect of nigericin on annexin V binding was significantly blunted, but not abolished by removal of extracellular Ca(2+). The nigericin-induced increase in [Ca(2+)]i and annexin V binding was again significantly blunted but not abolished by the Na(+)/H(+) exchanger inhibitor cariporide (10 µM). Nigericin triggers eryptosis, an effect paralleled by ROS formation, in part dependent on stimulation of Ca(2+) entry, and involving the cariporide-sensitive Na(+)/H(+) exchanger.

Connectivity of the intracytoplasmic membrane of Rhodobacter sphaeroides: a functional approach.

The photosynthetic apparatus in the bacterium Rhodobacter sphaeroides is mostly present in intracytoplasmic membrane invaginations. It has long been debated whether these invaginations remain in topological continuity with the cytoplasmic membrane, or form isolated chromatophore vesicles. This issue is revisited here by functional approaches. The ionophore gramicidin was used as a probe of the relative size of the electro-osmotic units in isolated chromatophores, spheroplasts, or intact cells. The decay of the membrane potential was monitored from the electrochromic shift of carotenoids. The half-time of the decay induced by a single channel in intact cells was about 6 ms, thus three orders of magnitude slower than in isolated chromatophores. In spheroplasts obtained by lysis of the cell wall, the single channel decay was still slower (~23 ms) and the sensitivity toward the gramicidin concentration was enhanced 1,000-fold with respect to isolated chromatophores. These results indicate that the area of the functional membrane in cells or spheroplasts is about three orders of magnitude larger than that of isolated chromatophores. Intracytoplasmic vesicles, if present, could contribute to at most 10% of the photosynthetic apparatus in intact cells of Rba. sphaeroides. Similar conclusions were obtained from the effect of a ∆pH-induced diffusion potential in intact cells. This caused a large electrochromic response of carotenoids, of similar amplitude as the light-induced change, indicating that most of the system is sensitive to a pH change of the external medium. A single internal membrane and periplasmic space may offer significant advantages concerning renewal of the photosynthetic apparatus and reallocation of the components shared with other bioenergetic pathways.

Efficacy of in-feed preparations of an anticoccidial, multienzyme, prebiotic, probiotic, and herbal essential oil mixture in healthy and Eimeria spp.-infected broilers.

The efficacies of 5 widely used dietary supplements were investigated on performance indices, fecal oocyst excretion, lesion score, and intestinal tract measurements in healthy and Eimeria spp.-infected birds by using a comparative model. This study included 2,400 sexed Ross 308 broiler chicks that were equally divided in 2 groups: the infected group, experimentally infected with oocysts of mixed Eimeria spp. at 14 d of age, and the healthy controls. The birds in both groups were further divided equally into 6 groups, of which one was fed a basal diet and served as control without treatment and the other 5 served as experimental treatments. These 5 groups were fed 5 diets containing preparations of 60 mg/kg of anticoccidial salinomycin (SAL), 1 g/kg of multienzyme (ENZ), 1 g/kg of probiotic (PRO), 1 g/kg of prebiotic (PRE), and 40 mg/kg of an herbal essential oil mixture (EOM). Body weight gain and feed conversion ratio (FCR) showed significant improvement in the infected animals, which indicates that dietary supplemental regimens with SAL, ENZ, PRO, and PRE initiated in 1-d-old chicks reduced adverse effects after challenge with coccidiosis; however, chicks that were administered EOM failed to show such improvement. Uninfected chickens showed significant improvement in FCR with supplements SAL, PRE, and EOM, which signifies significant (P < 0.01) infection by supplement interactions for BW gain and FCR. In the infected group, all of the supplements reduced the severity of coccidiosis lesions (P < 0.01) induced by mixed Eimeria spp. through the middle and lower regions of the small intestines, whereas supplementation with SAL or EOM alone was effective (P < 0.01) in reducing oocyst excretion compared with the control treatment. The data indicated that use of these subtherapeutically efficacious supplements (except EOM) in broiler production can lessen the depression in growth due to coccidial challenge.

Effect of three polyether ionophores on pharmacokinetics of florfenicol in male broilers.

Drug-drug interactions (DDIs) may adversely affect the prevention and cure of diseases. The effects of three polyether ionophore antibiotics, salinomycin (SAL), monensin (MON), and maduramycin (MAD) on the pharmacokinetics of florfenicol (FFC) were investigated in broilers. The chickens were fed rations with or without SAL (60 mg/kg feeds), MON (120 mg/kg feeds), or MAD (5 mg/kg feeds) for 14 consecutive days. FFC was given to the chickens either intravenously (i.v.) or orally (p.o.) at a single dose of 30 mg/kg body weight. Blood samples were taken from each chicken at 0-24 h postadministration of FFC. The plasma concentration of FFC was detected by high-performance liquid chromatography. The plasma concentration of FFC decreased with i.v. or p.o. co-administration of SAL, MON, or MAD in broilers, implying occurrence of DDIs during the co-administration of FFC with these ionophores. Our findings suggest that more attention should be given to the use of FFC to treat bacterial infections in chickens supplemented with polyether ionophore antibiotics.

Tissue Doppler imaging and 2-dimensional speckle tracking of left ventricular function in horses exposed to lasalocid.

BACKGROUND: Tissue Doppler imaging (TDI) and 2-dimensional speckle tracking (2DST) can quantify left ventricular (LV) function in horses. OBJECTIVES: To evaluate LV function by TDI and 2DST in horses with myocardial dysfunction after accidental ionophore intoxication. ANIMALS: Sixty-seven horses exposed to lasalocid in feed. METHODS: Prospective study. Horses were included in the study if a full cardiac examination was performed, consisting of determination of cardiac troponin I (cTnI), electrocardiography, and echocardiography. By TDI, radial systolic velocity and strain were measured. By 2DST, circumferential (SC) and radial (SR) strain at papillary muscle and chordal level and longitudinal (SL) strain were measured. RESULTS: Twenty horses showed signs of myocardial injury. Forty-nine examinations were performed on these horses between day 30 and 490 after suspected onset of exposure. Five horses had increased cTnI and ventricular tachycardia and 15 had increased cTnI without ventricular tachycardia. Horses with mild myocardial damage showed few significant differences compared with a control group. Horses with severe myocardial damage showed severely decreased TDI, 2DST and fractional shortening measurements (P < .05), indicating impaired LV function. Long-term follow-up of 2 surviving horses demonstrated full recovery in 1 horse and permanent myocardial fibrosis in the other. The lowest measurements per horse (n = 20) for all TDI measurements, SL, SR at chordal level, and FS correlated significantly with maximal cTnI (P < .05). Over all examinations (n = 49), TDI and 2DST measurements correlated well with FS (P < .05). CONCLUSIONS AND CLINICAL IMPORTANCE: The TDI and 2DST measurements allowed accurate detection and quantification of LV dysfunction in horses exposed to lasalocid.

The environmental and economic impact of removing growth-enhancing technologies from U.S. beef production.

The objective of this study was to quantify the environmental and economic impact of withdrawing growth-enhancing technologies (GET) from the U.S. beef production system. A deterministic model based on the metabolism and nutrient requirements of the beef population was used to quantify resource inputs and waste outputs per 454 × 10(6) kg of beef. Two production systems were compared: one using GET (steroid implants, in-feed ionophores, in-feed hormones, and beta-adrenergic agonists) where approved by FDA at current adoption rates and the other without GET use. Both systems were modeled using characteristic management practices, population dynamics, and production data from U.S. beef systems. The economic impact and global trade and carbon implications of GET withdrawal were calculated based on feed savings. Withdrawing GET from U.S. beef production reduced productivity (growth rate and slaughter weight) and increased the population size required to produce 454 × 10(6) kg beef by 385 × 10(3) animals. Feedstuff and land use were increased by 2,830 × 10(3) t and 265 × 10(3) ha, respectively, by GET withdrawal, with 20,139 × 10(6) more liters of water being required to maintain beef production. Manure output increased by 1,799 × 10(3) t as a result of GET withdrawal, with an increase in carbon emissions of 714,515 t/454 × 10(6) kg beef. The projected increased costs of U.S. beef produced without GET resulted in the effective implementation of an 8.2% tax on beef production, leading to reduced global trade and competitiveness. To compensate for the increase in U.S. beef prices and maintain beef supply, it would be necessary to increase beef production in other global regions, with a projected increase in carbon emissions from deforestation, particularly in Brazil. Withdrawing GET from U.S. beef production would reduce both the economic and environmental sustainability of the industry.

A phase I study of the metal ionophore clioquinol in patients with advanced hematologic malignancies.

UNLABELLED: Clioquinol is a small-molecule metal ionophore that inhibits the proteasome through a metal-dependent mechanism. Here, we report a phase I study of clioquinol in patients with refractory hematologic malignancies. Neuropathy and abdominal pain were dose-limiting toxicities. Minimal pharmacodynamic effects were observed, and there were no clinical responses. BACKGROUND: Clioquinol is a small-molecule metal ionophore that inhibits the enzymatic activity of the proteasome and displays preclinical efficacy in hematologic malignancies in vitro and in vivo. Therefore, we conducted a phase I clinical trial of clioquinol in patients with refractory hematologic malignancies to assess its safety and determine its biological activity in this patient population. METHODS: Patients with refractory hematologic malignancies were treated with increasing doses of oral clioquinol twice daily for 15 doses. Plasma and intracellular levels of clioquinol were measured. Enzymatic activity of the proteasome was measured before and after drug administration. RESULTS: Sixteen cycles of clioquinol were administered to 11 patients with 5 patients reenrolled at the next dose level as per the permitted intrapatient dose escalation. Dose-limiting neurotoxicity and abdominal pain were observed at a dose of 1600 mg twice daily. Intracellular drug levels were low. Minimal inhibition of the proteasome was observed. No clinical responses were observed. CONCLUSION: In patients with refractory hematologic malignancies, the maximal tolerated dose of clioquinol was determined. Minimal inhibition of the proteasome was observed at tolerable doses, likely due to low intracellular levels of the drug.

Effects of a xylanase and protease, individually or in combination, and an ionophore coccidiostat on performance, nutrient utilization, and intestinal morphology in broiler chickens fed a wheat-soybean meal-based diet.

The effects of 2 single exogenous and monocomponent feed enzymes, and their combination, and an ionophore coccidiostat on production performance, feed AME(n), nutrient utilization, and intestinal morphology were studied in broiler chickens. One-day-old unvaccinated and unsexed Ross 308 birds (n = 320) were kept in groups of 8 on wood shavings in pens raised from the floor and fed one of 5 experimental diets, replicated 8 times, for 36 d. Treatments were 1) a wheat-soybean meal-based feed with no added coccidiostats or exogenous enzymes (CON), 2) CON + ionophore coccidiostat (Narasin), 3) CON + xylanase (Ronozyme WX CT; XYL), 4) CON + serine protease (Ronozyme ProAct CT; PRO), or 5) CON + xylanase + serine protease (XYL+PRO). Enzymes were added on top in the feed formulation. Diets contained 0.5% TiO2 to facilitate estimations of total tract apparent nutrient utilization. Treatments had no effect on BW gain or feed intake, but feed conversion, apparent digestibility of starch and fat, and feed AME(n) were improved with all enzyme treatments. The relative length of the ileum was reduced with XYL+PRO. For all parameters measured, the effects of XYL+PRO were similar to when XYL and PRO were fed individually. Narasin had no effect on production performance or nutrient utilization but reduced the relative lengths of jejunum and ileum. Relative lengths and weights of duodenum and cecum were unaffected by treatments. In conclusion, the improved feed conversion with both a xylanase and a protease was reflected in increased nutrient utilization, but their combination was not superior to when supplied separately. Narasin did not affect performance or nutrient utilization but reduced the relative lengths of the jejunum and ileum.

Surtos de intoxicação por salinomicina em chinchilas (Chinchilla lanigera) / Outbreaks of salinomycin toxicosis in Chinchillas (Chinchilla lanigera)

Quatro surtos de intoxicação por salinomicina são descrito em chinchilas de três municípios do Estado do Rio Grande do Sul. Uma semana após a ingestão de ração contendo 37 ppm de salinomicina, aproximadamente duas mil chinchilas de quatro fazendas expostas diminuíram o consumo da ração. Quatrocentos e vinte sete chinchilas demonstraram apatia. Dessas, duzentos e setenta e sete desenvolveram decúbito esternal e lateral, dispneia e coma, seguidos de morte. As primeiras mortes ocorreram oito dias após a ingestão da ração. A evolução dos sinais clínicos até a morte ou eutanásia foi de 2-5 dias. Os exames bioquímicos do soro sanguíneo em quatro chinchilas revelaram níveis aumentados da alanina aminotransferase, aspartato transaminase, fosfatase alcalina, creatina cinase, glicose, triglicerídeos e colesterol total. Quarenta e cinco chinchilas foram submetidas à necropsia. Os achados macroscópicos consistiam de marcada lipidose hepática em todas as chinchilas necropsiadas; fetos em estado de decomposição em doze chinchilas que estavam prenhes. Microscopicamente, múltiplas fibras musculares esqueléticas estavam hipereosinofílicas, tumefeitas e com perda das estriações. Nas chinchilas que sobreviveram por mais dias era possível observar segmentos fragmentados de miofibras afetadas (necrose flocular) e regeneração de miofibras. No fígado foi observada marcada degeneração gordurosa. Não foram observadas anormalidades microscópicas nos demais órgãos analisados. Análises à procura de aflatoxinas, resíduos de pesticidas e isolamento bacteriano foram negativos. A análise da ração por cromatografia líquida revelou 37ppm de salinomicina na ração. A ração suspeita foi administrada a 12 chinchilas, três das quais (25 por cento) morreram apresentando lesões semelhantes às observadas nas chinchilas com a doença natural. O diagnóstico de intoxicação por salinomicina foi baseado na epidemiologia, lesões histológicas características e na presença de salinomicina na ração administrada nas quatro criações envolvidas.

Four outbreaks of ionophore toxicosis are described in chinchillas from four commercial farms located in three municipalities in the state of Rio Grande do Sul, southern Brazil. Approximately 2,000 chinchillas showed decrease in food intake one week after start ingesting a ration containing 37 ppm of salinomycin. Four hundred and twenty seven chinchillas showed apathy. Of those 277 develop sternal and lateral recumbence, dyspnea and coma followed by death. First deaths occurred eight days after the start on the salinomycin containing ration; clinical course was 2-5 days. Serum chemistry carried out in four chinchillas revealed increased levels of alanine transaminase, aspartate transaminase, alkaline phosphatase, creatinenin kinase, glucose, triglicerids and total cholesterol. Forty five affected chinchillas were necropsied; consistent necropsy findings were marked hepatic lipidosis; additionally twelve pregnant chinchillas had dead decomposing fetuses. Microscopically skeletal muscles had multifocally swollen hypereosinophilic myofibers with loss of cross striations. In those chinchillas that survived longer than a few days, microscopic features in the skeletal muscle included segmental fragmentation of dead fibers (floccular necrosis) and myofiber regeneration. Marked fatty degeneration was observed in the livers of all affected chinchillas. No microscopic changes were observed in other organs. Chemical analysis in the feed consumed by the chinchillas did not detect aflatoxins or pesticides residues; bacterial culture performed in samples of liver and intestinal contents from necropsied chinchillas yielded no significant bacterial growth. Analysis by thin layer chromatography performed in the ration consumed by the chinchillas detected 37 ppm of salinomycin. The suspected ration was fed to 12 chinchillas three of which (25 percent) died with similar lesions to those observed in the natural cases. The diagnosis of salinomycin toxicosis was based in the epidemiology, histology of the lesions, on the detection of significant amounts of salinomycin in the ration used to feed the chinchillas in the four involved farms and on the reproduction of disease by feeding the suspected ration to susceptible chinchillas.