Biomass allocation strategies and Pb-enrichment characteristics of six dwarf bamboos under soil Pb stress.

Dwarf bamboos are clonal plants with potential applications in the remediation of heavy metal-polluted soils, although their pollution adaptation strategies are unknown. This study examined the biomass allocation strategies and lead (Pb) enrichment characteristics of various dwarf bamboo tissues by the end of the growing season and explored their potential for phytoremediation of Pb stress in the soils. Six dwarf bamboo genotypes were treated with three levels (0, 300, and 1500 mg kg-1) of soil Pb stress. The majority of the bamboos adopted two biomass allocation strategies to adapt to Pb stress, namely, "reducing biomass allocation into new bamboo growth" and "increasing/stabilizing biomass allocation into rhizomes". Pb accumulation was highest in the roots, rhizomes, and old stems and showed the following trend: rhizomes/old stems> new roots/old roots> old leaves> new leaves> new stems among various tissues. Moreover, the six bamboos used three different Pb-enrichment strategies, as follows: (i) "rhizome domination and old stem synergy" (Sasaella glabra (Nakai) f. albo-striata Muroi, Sasa auricoma (Mitford) E.G. Camus, Sasa fortunei (Van Houtte) Fiori, and Shibataea lanceifolia C.H. Hu); (ii) "old stem domination and rhizome synergy" (Indocalamus decorus Q.H. Dai); and (iii) "old stem domination and new root synergy" (Sasa argenteostriata (Regel) E.G. Camus). In Pb-contaminated soils, genotypes with TFs greater than 1 were Sasa fortunei (Van Houtte) Fiori, Sasa argenteostriata (Regel) E.G. Camus, and Indocalamus decorus Q.H. Dai; in addition, only S. argenteostriata had BCF values greater than 1. Furthermore, this study provides the first evidence that S. argenteostriata can extract 0.22 and 0.58 mgplant-1 of Pb ions in soil polluted with 300 and 1500 mg kg-1 Pb, respectively. S. argenteostriata showed the greatest potential for phytoremediation among the bamboo genotypes in both Pb-contaminated urban and mining sites.

Evaluation of Resistance to Fescue Toxicosis in Purebred Angus Cattle Utilizing Animal Performance and Cytokine Response.

Fescue toxicosis is a multifaceted syndrome common in cattle grazing endophyte-infected tall fescue; however, varying symptomatic responses potentially imply genetic tolerance to the syndrome. It was hypothesized that a subpopulation of animals within a herd would develop tolerance to ergot alkaloid toxicity. Therefore, the goals of this study were to develop selection criteria to identify tolerant and susceptible animals within a herd based on animal performance, and then examine responsive phenotypic and cytokine profiles to fescue toxicosis. Angus cows grazed endophyte-infected tall fescue at two locations for 13 weeks starting in mid-April 2016. Forage measurements were collected to evaluate ergot alkaloid exposure during the study. A post hoc analysis of animal performance was utilized to designate cattle into either tolerant or susceptible groups, and weekly physiological measurements and blood samples were collected to evaluate responses to chronic exposure to endophyte-infected tall fescue. Findings from this study support the proposed fescue toxicosis selection method formulated herein, could accurately distinguish between tolerant and susceptible animals based on the performance parameters in cattle chronically exposed to ergot alkaloids, and provides evidence to warrant additional analysis to examine the impact of ergot alkaloids on immune responsiveness in cattle experiencing fescue toxicosis.

A botanical from the antiproliferative Cameroonian spice, Imperata cylindrica is safe at lower doses, as demonstrated by oral acute and sub-chronic toxicity screenings.

BACKGROUND: The cytotoxicity of the root's methanol extract of Imperata cylindrica (ICR). was previously reported in a panel of human cancer cell lines, including multi-drug resistant phenotypes. The aim of this study was to assess the acute and sub-chronic oral toxicity of methanol root extract of Imperata cylindrica. METHODS: The acute toxicity was carried out according to the experimental protocol of OECD. The plant extract was administered orally to female rats at a single dose of 5000 mg/kg for 14 days and the animals were observed for any behavioral changes or mortality. For sub-chronic toxicity study, ICR was orally administered daily to male and female rats at different doses (250, 500 and 1000 mg/kg per b.w.) for 30 days. During these treatment days the animals were observed for any appearance of toxicity symptoms; following the treatment period, animals were sacrificed for hematological, biochemical and histopathology analysis. RESULTS: From the results of the acute oral toxicity assay, ICR was found to be non-toxic at the dose of 5000 mg/kg b.w. During the period of sub-chronic toxicity test, observation of signs, behavior and health status of the animals showed no abnormality in the groups of animals treated with ICR as compared to the controls. Significant variation of the relative body weights of heart and kidney were observed at dose a 1000 mg/kg b.w. Significant decrease of aspartate aminotransferase, creatinine level, low density lipoprotein concentration, triglyceride and total cholesterol were observed. In males, we noticed a significant decrease of the level of granulocytes with an increase of lymphocytes and mean corpuscular hemoglobin concentration levels. Histological examinations performed on kidney and liver showed a normal kidney architecture and liver also presented a normal hepatic architecture with slight degeneration at a dose 1000 mg/kg b.w. CONCLUSION: ICR is safe for acute oral administration; however, for long-term oral administration, safety measures should be taken. Thus, oral sub-chronic exposure of ICR at lower doses are recommended while higher doses around 1000 mg/kg b.w. should be discouraged.

Metabolomics of fescue toxicosis in grazing beef steers.

Fescue toxicosis (FT) results from consumption of tall fescue (Lolium arundinaceum) infected with an endophyte (Epichloë coenophiala) that produces ergot alkaloids (EA), which are considered key etiological agents of FT. Decreased weight gains, hormonal imbalance, circulating cholesterol disruption, and decreased volatile fatty acid absorption suggest toxic (E+) fescue-induced metabolic perturbations. Employing untargeted high-resolution metabolomics (HRM) to analyze E+ grazing-induced plasma and urine metabolome changes, fescue-naïve Angus steers were placed on E+ or non-toxic (Max-Q) fescue pastures and plasma and urine were sampled before, 1, 2, 14, and 28 days after pasture assignment. Plasma and urine catecholamines and urinary EA concentrations were also measured. In E+ steers, urinary EA appeared early and peaked at 14 days. 13,090 urinary and 20,908 plasma HRM features were detected; the most significant effects were observed earlier (2 days) in the urine and later (≥14 days) in the plasma. Alongside EA metabolite detection, tryptophan and lipid metabolism disruption were among the main consequences of E+ consumption. The E+ grazing-associated metabolic pathways and signatures described herein may accelerate development of novel early FT detection and treatment strategies.

Allergenicity of Gramineae bee-collected pollen is proportional to its mass but is highly variable and depends on the members of the Gramineae family

BACKGROUND: Gramineae bee-collected pollen is identified as being at the origin of allergic accidents but the biological potency of Gramineae bee-collected pollen is not well known. Cereal grasses (e.g., Zea) and European wild forage grasses (FG) are contained in bee-collected pollen. METHOD: In this experiment, Zea-mass and FG-mass were identified in bee pollen mass and the proportion of Zea and of FG was calculated using the bee pollen melissopalynology spectrum. Skin reactivity to Zea and to FG were assessed by measuring wheal diameters (W) from skin prick tests using three serial dilutions of bee-collected pollen on 10 allergic patients to Gramineae, in order to calculate the relationship between Zea mass (Masszea) or FG mass (MassFG) in bee pollen and skin reactivity. RESULTS: The linear function Log10(WFG) = 0.24(Log10(MassFG)) + 0.33 (R = 0.99) was established using a bee pollen sample with 0.168 mg of FG pollen per mg. The linear function Log10(Wzea) = 0.23(Log10(Masszea)) + 0.14 (R = 0.99) was established using a bee pollen sample with 0.983 mg of Zea pollen per mg. Gramineae allergens seem to be little altered by bee secretions. Gramineae bee pollen retains its allergenic capacity but it depends on the members of the Gramineae family. CONCLUSIONS: To our knowledge this is the first time it has been shown that skin reactivity to Gramineae is proportional to the absolute Gramineae mass contained in the bee-collected pollen and that it depends on the members of the Gramineae family

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Spontaneous poisoning by brachiaria decumbens in goats / Intoxicação espontânea por brachiaria decumbens em caprinos

An outbreak of Brachiaria decumbens poisoning in goats in the state of Mato Grosso do Sul, Brazil, is described. Out of a herd of about 1,000 goats, seven goats died after showing photosensitivity (3 out 7 goats) and icterus (4/7). Other clinical signs included lethargy, dehydration and weight loss (7/7). At necropsy there was either hepatomegaly or liver atrophy; orange, yellow or gray discoloration - were observed in the liver of six goats. Two had accentuation of lobular pattern and punctate, linear or stellar fibrous depressions were randomly distributedover the capsular surface. Macroscopic changesattributedto liver failure consisting of hydropericardium (2/7) and ascites (2/7) were observed. Histologically, there was accumulation of refringent crystals in the bile ducts and infiltration of foamy macrophages in the liver of all goats. Foamy macrophages were also present in the hepatic and mesenteric lymph nodes of two goats. The diagnosis of B. decumbens poisoning was based on epidemiology, clinical signs, necropsy findings and histopathology.

Relata-se um surto de intoxicação por Brachiaria decumbens em caprinos no estado do Mato Grosso do Sul. De um rebanho de aproximadamente 1.000 caprinos, sete cabras morreram após apresentar fotossensibilização (3 de 7 cabras) e icterícia (4/7). Outros sinais clínicos incluíam apatia, desidratação e emagrecimento (7/7). Todas as cabras tinham alteração no tamanho do fígado - cinco estavam aumentados de volume e dois, diminuídos; o fígado de 6 cabras tinha alteração na cor - dois eram alaranjados, dois amarelados e dois, acinzentados; o fígado de duas cabras tinha acentuação do padrão lobular e outros dois apresentavam depressões fibrosas puntiformes, lineares ou estreladas, brancacentas distribuídas aleatoriamente pela superfície capsular. Adicionalmente, foram observadas alterações macroscópicas atribuídas à insuficiência hepática como hidropericárdio (2/7) e ascite (2/7). Alterações histopatológicas incluíam cristais refringentes nos ductos biliares e infiltrado de macrófagos espumosos no parênquima hepático de todas as cabras. Macrófagos espumosos também foram observados nos linfonodos mesentéricos e hepáticos em duas cabras. O diagnóstico de intoxicação por braquiária foi baseado na epidemiologia, achados clínicos, de necropsia e histopatológicos.

Effects of selected endophyte and tall fescue cultivar combinations on steer grazing performance, indicators of fescue toxicosis, feedlot performance, and carcass traits.

Five tall fescue [Lolium arundinaceum (Schreb.)] pastures [wild-type 'Kentucky-31' with 78.0% of plants infected with ergot alkaloid-producing endophyte Neotyphodium coenophialum (KY31 E+), 'Jesup' AR542 endophyte-infected contaminated with 30.3% tall fescue containing ergot alkaloid producing-endophyte (Jesup AR542 E+); 'GA-186' AR584 endophyte-infected contaminated with 11.8% tall fescue containing ergot alkaloid producing-endophyte (AGRFA 140); 'PDF' AR584 endophyte-infected contaminated with 5.5% tall fescue containing ergot alkaloid producing-endophyte (AGRFA 144); and 'KYFA 9301' AR584 endophyte-infected contaminated with 10.0% tall fescue containing ergot alkaloid producing-endophyte (AGRFA 150)] were compared for steer growth performance, toxicity, feedlot performance, and carcass traits. Steers (mean initial BW=322 kg) grazed pastures for 84 d in spring and 56 d in autumn for 2 yr. Steers were shipped after grazing in Prairie, MS, to Macedonia, IA, for finishing. Mean herbage mass was not different (P=0.15) among pastures. Posttreatment (d 28+) serum prolactin concentrations were depressed (P=0.013) on KY31 E+. Steers grazing KY31 E+ had greater (P<0.01) posttreatment rectal temperatures during spring. Spring hair coat scores were greatest (P<0.01) on KY31 E+ at d 56 and 84. Steer ADG was least (P<0.01) on KY31 E+ in spring and depressed (P=0.014) on KY31 E+ and Jesup AR542 E+ in autumn. Spring grazing ADG was greater (P=0.049) on AGRFA 150 than Jesup AR542 E+ and AGRFA 140. No BW differences (P=0.09) among pastures were seen at reimplant during feedlot finishing. Pasture had no effect on ADG after reimplant (P=0.68), days on feed (P=0.56), or final BW (P=0.55). Exposure to fescue toxicosis did not affect (P≥0.19) carcass traits. Hair coat price discounts applied for spring-grazed steers on KY-31 E+ affected (P<0.01) initial steer monetary values. There were no pasture differences for finishing costs (P≥0.61) or final carcass value (P=0.59). Elite tall fescue cultivar and novel endophyte combinations improve growth performance of grazing calves over KY31 E+. Producers whose calves graze KY-31 E+ tall fescue should consider retaining ownership of these cattle through feedlot finishing to avoid market discounts and capture value from compensatory BW gains during finishing.

A review of the most economically important poisonous plants to the livestock industry on temperate grasslands of China.

The majority of the literature on poisonous plant species in China is published in Chinese and not available to the majority of interested researchers and grassland managers in other countries. Therefore, a review of the Chinese literature was conducted to summarize the occurrence of poisonous plant species on temperate grasslands in China. We reviewed the literature to obtain general information on poisonous species but focus on locoweeds (Astragalus and Oxytropis spp.), drunken horse grass [Achnatherum inebrians (Hance) Keng ex Tzvelev] and langdu (Stellera chamaejasme L.) for information on their toxins, distribution and ecology, control methods and alternate uses. Of the almost 1300 poisonous species found on grasslands in China, these species are responsible for an estimated 80% of all livestock losses. This includes loss of performance as well as mortality. The locoweeds are a complex made up of Oxytropis and Astragalus species. The toxic principle in this complex, as well as in drunken horse grass, is the result of an endophyte fungus whereas in langdu it is produced by the plant. All these species are native to the grasslands, which suggest they have been a problem ever since herding began. Over that period of at least several millennia, herders would have learned and adapted to the presence of poisonous species. Strategies were developed and therapies employed to allow the animals to cope before and after poisoning. Nevertheless, grazing management could still be refined that would allow the use of the toxic legumes, while preventing poisonous symptoms, as has been tested elsewhere.

Organic dust toxic syndrome at a grass seed plant caused by exposure to high concentrations of bioaerosols.

We describe an outbreak of sudden health problems in workers at a Danish grass seed plant after exposure to a particularly dusty lot of grass seeds. The seeds are called problematic seeds. The association between development of organic dust toxic syndrome (ODTS) and the handling of grass seeds causing exposure was assessed in a four-step model: (i) identification of exposure source, (ii) characterization of the emission of bioaerosols from the problematic and reference seeds, (iii) personal and stationary exposure measurement at the plant and (iv) repeated health examinations. The grass seeds were identified as the exposure source; the emissions of some bioaerosol components were up to 10(7) times higher from the problematic seeds than from reference seeds. Cleaning of the seeds was not enough to sufficiently reduce the high emission from the problematic seeds. Emission in terms of dust was 3.4 times as high from the problematic cleaned seeds as from cleaned reference seeds. The personal exposure reached 3 × 10(5) endotoxin units m(-3), 1 × 10(6) colony-forming units (cfu) of thermophilic actinomycetes m(-3), 8 × 10(5) cfu of Aspergillus fumigatus m(-3) and 9 × 10(6) hyphal fragments m(-3). Several workers working with the problematic seeds had symptoms consistent with ODTS. The most severe symptoms were found for the workers performing the tasks causing highest exposure. Respiratory airway protection proved efficient to avoid development of ODTS. Work with reference seeds did not cause workers to develop ODTS. Exposure was during work with the problematic seeds higher than suggested occupational exposure limits but lower than in studies where researchers for some minutes have repeated a single task expected to cause ODTS. In this study, many different bioaerosol components were measured during a whole working day. We cannot know, whether it is the combination of different bioaerosol components or a single component which is responsible for the development of ODTS. In conclusion, workers developed specific health symptoms due to the high bioaerosol exposure and were diagnosed with ODTS. Exposure to high concentrations of endotoxin, actinomycetes, fungi, hyphal fragments, ß-glucan, and A. fumigatus occurred when working with a dusty lot of grass seed. Suspicion should be elicited by seeds stored without being properly dried and by seeds producing more dust than usually.

Distribution of imidacloprid residues in different parts of rice plants and its effect on larvae and adult females of Chilo suppressalis (Lepidoptera: Pyralidae).

The distribution of imidacloprid residue in different parts of rice, Oryza sativa L. (Graminales: Poaceae), plants was investigated for three rice varieties. Changes in larval hormones in Chilo suppressalis (Walker) (Lepidoptera: Pyralidae) that fed on imidacloprid-treated plant sources and the fecundity of resultant adult females (moths) also were determined. No significant differences in imidacloprid residue were detected in rice stem, leaves, and the unexpanded new leaf 7 d after treatment except in the rice variety Fengyouxiangzhan, in which residue content in leaves and the unexpanded new leaf was significantly lower than that in the stem. The percentage of reduction of imidacloprid residue after treatment varied with rice variety and plant parts. The greatest reduction in the three plant parts was shown in Wujing 15 compared with the other two varieties. The decomposition rate of imidacloprid residue in Wujing 15 was greater in leaves and unexpanded new leaf than in the stem, whereas in Wuyunjing 7 it was lower in leaves than in the unexpanded new leaf and stem. In Fengyouxiangzhan, the decomposition rate of imidacloprid in the stem increased 14 d after treatment. Juvenile hormone III and molting hormone titers in fourth instar larvae that had fed on rice plants treated with imidacloprid since the neonate stage were significantly higher than those in larvae fed on untreated plants (control). Juvenile hormone titer in larvae that had fed on Zizamia lalifolia Turcz galls treated with imidacloprid and the fecundity of the female moths that developed from such larvae were also significantly higher than that on the control counterparts. These results are discussed in relation to the impact of imidacloprid on nontarget insects and pest management.

Residual effects of imidacloprid on Japanese beetle (Coleoptera: Scarabaeidae) oviposition, egg hatch, and larval viability in turfgrass.

Preventive control of turf-infesting scarabaeid grubs by neonicotinoid insecticides is presumed to mainly result from residues killing first instars in the soil. The extent to which sublethal behavioral effects or intoxication of other life stages contribute to such control is poorly known. We tested whether Japanese beetle, Popillia japonica Newman, females lay fewer eggs in turf treated with imidacloprid (Merit 75 WP) or an imidacloprid-bifenthrin combination (Allectus GC SC), and whether exposure to those residues in thatch and soil reduces their survival and subsequent ability to feed or take flight. Effects of imidacloprid residues on egg hatch and viability of successive larval instars also were studied. In two sets of choice tests, 68 and 82% fewer eggs were laid in Kentucky bluegrass with Allectus residues than in controls. When females were confined in treated turf, however, neither insecticide consistently reduced their fecundity or affected depth at which eggs were laid, although exposure to fresh Allectus residues reduced the beetles' subsequent viability. Imidacloprid residues up to 2 ppm in soil did not affect egg viability or days to hatch, but they killed neonates soon after eclosion. Imidacloprid curatively applied at label rate (0.34 kg active ingredient/ha) reduced weight gain, burrowing capability, frass production, and survival of second and third instars in turfgrass cores, with high mortality within 30 d. Intoxication and behavioral impairment of third instars also occurred in autumn field trials. Our data suggest that imidacloprid has greater activity against late instars than is generally appreciated.

Intoxicação por Sorhgum halepense (Poaceae) em bovinos no semi-árido / Poisoning by Sorghum halepense (Poaceae) in cattle in the Brazilian semiarid

Descreve-se um surto de intoxicação por Sorghum halepense (L.) Pers. no município de Santa Luzia, semi-árido da Paraíba. Nove bovinos foram colocados numa pastagem com S. halepense em fase de rebrota, com 25-30cm de altura, 15 dias após as primeiras chuvas. Sinais clínicos de dispnéia, ansiedade, tremores musculares e incoordenação apareceram 10-15 minutos após a ingestão. Dois animais morreram em um período aproximado de 3 horas. Na necropsia observaram-se congestão e cianose das mucosas, musculatura escura, pulmão com pontos hemorrágicos e edema, além de folhas da planta no rúmen. A planta foi positiva no teste do papel picrosódico. Mudas de S. halepense coletadas no Município de Currais Novos, Rio Grande do Norte, onde havia históricos de uma intoxicação semelhante, foram plantadas em vasos e realizado o teste de papel picrosódico a cada 15 dias. A planta foi positiva para HCN durante todos os estágios, sendo que nos primeiros 45 dias a reação ocorreu dentro de 1 minuto e, posteriormente, em até 3 minutos. Trinta dias após ter sido plantada, a planta de um dos vasos foi administrada a um caprino causando sinais característicos de intoxicação cianídrica na dose de 11,8g/kg de peso do animal. O caprino se recuperou após tratamento com uma solução de tiossulfato de sódio a 20% na dose de 5mL/10kg. No semi-árido, S. halepense é freqüentemente encontrado como invasora em beiras de açudes e culturas irrigadas, sendo utilizado como forrageira, na época seca, em áreas de vazante.

An outbreak of poisoning by Sorghum halepense (L.) Pers. in cattle in the Brazilian semiarid is reported. Nine cattle were introduced 15 days after the first rains into a paddock where the plant was sprouting and had 25-30cm high. Clinical signs of dyspnea, anxiety, muscular tremors and incoordination appeared 15 minutes after the animals began to graze. Two of them died within about 3 hours. The others recovered. Cyanotic mucosa, dark muscles, lung edema and hemorrhages, and leaves of the plant in the rumen were observed at necropsy. The plant was positive for the picrosodic paper test. S. halepense from another farm of occurrence of the poisoning was transplanted into two pots. The picrosodic paper test was performed fortnightly in the plants growing in one of them. The plant was positive for cyanide in all growth stages; during the first 45 days the test was positive within 1 minute, but after day 60 within 3 minutes. Thirty days after the plant had been transplanted into one of the pots, it was administered to a goat at a dose of 11.8g/kg, causing clinical signs of HCN poisoning. The animal recovered after the intravenous administration of 5mL/10kg body weight of a 20% sodium thiosulfate solution. In the Brazilian semiarid S. halepense is frequently found invading the border of ponds and irrigated crops, and is used as forage during the dry season.

Study of experimentally induced lesions in sheep by grazing Brachiaria decumbens.

A histologic and ultrastructural study of the alterations found in the lymph nodes and livers of nine sheep with experimental cholangiohepatopathy by grazing on Brachiaria decumbens has been performed. Sheep were euthanized in three groups, on the 77th, 89th, and 150th days of the experimental feeding. The main gross lesions were whitish spots of multifocal distribution scattered throughout the hepatic parenchyma from all B. decumbens-grazed animals and whitish foci surrounded by reddened halos in the mesenteric and hepatic lymph nodes of sheep necropsied on the 150th. The principal histologic findings included hepatocellular cloudy swelling, marked multifocal cholangitis in the portal triads with bile duct proliferation and infiltration of macrophages and lymphocytes. Crystals were observed within bile ducts and surrounded by macrophages. Ultrastructurally, there were criytaloid structures within the macrophages and hepatocytes, which also presented hyperplasia of smooth endoplasmic reticulum. These findings suggest that hepatocytes were the initial target of the toxic effects, which depending on the degree of severity developed would cause both, subsequent cholangiopathy or occasional photosensitization. Additionally, the developmental stages of the hepatic lesions observed in this study have been presented.

Detection of endophyte toxins in the imported perennial ryegrass straw.

From 1997 to 1999, 29 cases of disorders were detected in cattle and horses that had been fed ryegrass straw imported from the U.S.A. These animals showed symptoms resembling ryegrass staggers and the clinical signs disappeared after removal of the straw. Endophytic hyphae were detected in the seeds of all straw samples that were responsible for the clinical cases. Lolitrem B concentrations in the straw ranged between 972 and 3740 ppb. Ergovaline concentrations were between 355 and 1300 ppb. Even though the concentrations of lolitrem B were lower than the toxic threshold proposed by Oregon State University in better part of the cases, our observations suggest the possibility that lolitrem B lower than the proposed threshold can bring disorders to sensitive individuals.

Effects of fescue and clover forage on serum lactate dehydrogenase and glucose 6-phosphate dehydrogenase isoenzymic profiles in steers.

We determined the effects of forage type on isoenzymes of lactate dehydrogenase (LDH) and glucose 6-phosphate dehydrogenase (G6PDH). Forty-eight crossbred steers were randomly allotted to replicated pastures consisting of fungus-infected (Neotyphodium coenophialum) fescue or fungus-free fescue each with or without ladino clover overseeding. At the end of the 180-d grazing period, serum was harvested from the steers. Steers were finished in a feedlot and slaughtered after approximately 150 d in the feedlot. Isoenzymes for LDH and G6PDH were separated using PAGE. Five LDH isoenzymes (L1-15) were typically detected. Isoenzyme L1 (most anodic) had the greatest area percent as detected by laser densitometry (72, 12, 10, 5, and 7%, respectively, for L1, L2, L3, L4, and L5). Four proteins had G6PDH activity (G1-G4) with G2 having the greatest area percent (15, 52, 27, and 14, respectively, for G1, G2, G3, and G4). Isoenzymes within a dehydrogenase were correlated (P < .05). In addition, area percentage of L1 was correlated (P < .05; r = .34) with area percentage of G2, and area percentage of L4 was correlated (P < .07; r = .73) with area percentage of G1. Area percentages of L1, L2, and L3 were affected by an interaction (P < .09) of forage types. Body weight gains for steers grazing endophyte-infected fescue were depressed (P < .05); however, steers compensated with increased (P < .05) weight gains during the finishing phase. Fungal toxins produced by Neotyphodium coenophialum may alter an animal's metabolism, growth, and development via shifts in reducing equivalents (NADH).

Isolation of steroidal sapogenins implicated in experimentally induced cholangiopathy of sheep grazing Brachiaria decumbens in Brazil.

As part of an experimental study, crystal-associated cholangiopathy was induced in 9 sheep by grazing pure pastures of Brachiaria decumbens in Brazil. One of these sheep showed characteristic lesions of photosensitization. The analysis of the B decumbens samples by acidic hydrolysis followed by TLC and infrared spectrum revealed diosgenin as the principal sapogenin present in the plant. In the rumen contents samples from the B decumbens-grazing group were identified by TLC, 1H and 13C NMR and EIMS as epismilagenin, episarsasapogenin, and a mixture of smilagenin and sarsasapogenin. In the bile samples from the B decumbens-grazing group, TLC analysis demonstrated 2 compounds similar to epismilagenin and episarsasapogenin. However, by this same method, those compounds were not observed in the rumen contents and bile from 2 sheep which served as control animals. The P chartarum spore counts remained very low during the experimental period.

Hemorrhagic diathesis, mesenteric hematoma, and colic associated with ingestion of sweet vernal grass in a cow.

A 4-year-old Holstein cow from a farm where 2 cows had recently died suddenly was referred for evaluation of acute severe colic. Right flank laparotomy revealed a large mesenteric hematoma. Within 14 layer chromatographic analyses of the moldy hay and blood from the necropsied cow and the hospitalized cow were positive for dicumarol. A diagnosis of sweet vernal poisoning was confirmed on the basis of clinical and toxicologic findings. The cow was treated with supportive therapy, blood transfusions, and vitamin K1 and recovered without complications. Because sweet vernal grass is becoming common in certain areas and the use of round bales is commonplace, practitioners should be aware of the potential for this toxicosis.

An outbreak of suspected poisoning of cattle by Dichapetalum sp. in Tanzania.

Between September and December 1995, 72 out of 476 cattle on 15 dairy farms in the Dar es Salaam region of Tanzania, died of suspected Dichapetalum poisoning. Following a drought and a resultant forage shortage, 12 of the farms had purchased hay from commercial farms in the Coast region, particularly from one seed and hay farm located about 60 km west of Dar es Salaam city. Following ingestion of the purchased hay, affected animals were acutely ill and their clinical signs included inappetence, dullness, high stepping gait, disinclination to move, jugular vein distension and gastrointestinal malfunctions. Fatal cases died suddenly after a short course of illness. Toxic plants identified as Dichapetalum mossambicense Engl. and D. stuhlmannii Engl. were found mixed in the hay. A diagnosis of Dichapetalum poisoning was made on the basis of history, clinical signs and post-mortem findings in fatal cases. On withdrawal of the contaminated hay, the outbreak subsided and deaths ceased. The findings of the investigation are discussed.

Evaluation of physiologic indices in mice vaccinated with protein-ergotamine conjugates and fed an endophyte-infected fescue diet.

OBJECTIVES: To assess effects of vaccination against fescue toxicosis on weight gain, serum prolactin and cholesterol concentrations, and alkaline phosphatase (ALP) activity in mice fed an endophyte-infected (EI) or endophyte-free (EF) fescue diet. ANIMALS: 50 six-week-old male BALB/c mice. PROCEDURE: Mice were randomly allocated to the following 5 groups: 1, vaccinated intraperitoneally with a bovine serum albumin-ergotamine (EG) conjugate and fed an EI fescue diet; 2, orally vaccinated with cholera toxin (CT) subunit B-EG conjugate mixed with free CT and fed an EI fescue diet; 3, not vaccinated and fed an EI fescue diet; 4, passively vaccinated with monoclonal antibodies specific for ergovaline (EV) and fed an EI fescue diet; and 5, not vaccinated and fed an EF fescue diet. RESULTS: Antibodies against EG and EV were in serum of mice of groups 1 and 4, respectively. Secretory IgA and IgG coproantibodies against EG were induced in mice of group 2. Weight increased in groups 1 and 2 and tended to be increased in group 4 versus group 3. Prolactin concentration was similar in all groups; cholesterol concentration was decreased in groups 1, 3, and 4, compared with group 5. Compared with that in group 5, serum ALP activity decreased in groups 1 and 4 and was further decreased in group 1, compared with that in groups 2 and 3; it was negatively correlated with anti-EG titer. CONCLUSIONS AND CLINICAL RELEVANCE: Induction of anti-EG antibodies and administration of EV monoclonal antibodies tended to increase short-term weight gain in this murine model of fescue toxicosis. However, systemic IgG antibodies against EG or EV antibodies were not protective against decreases in serum ALP activity and cholesterol concentrations. Clinical significance of decreased ALP activity associated with vaccination is unknown, but represents a worsening of a response often associated with fescue toxicosis in cattle.