Subacute toxicity of alpha-ergocryptine in Sprague-Dawley rats. 2: metabolic and hormonal changes

High deoxynivalenol and ergot alkaloid levels in wheat grain: effects on growth performance, carcass traits, rumen fermentation, and blood parameters of feedlot cattle

This study was designed to assess the impacts of a mixture of deoxynivalenol (DON) and ergot alkaloids (EAs) on growth performance, rumen function, blood parameters, and carcass traits of feedlot cattle. Forty steers (450 ± 6.0 kg) were stratified by weight and randomly allocated to 1 of 4 treatments; control-low (CON-L), control-high (CON-H) which contained low or high wheat screenings that lacked mycotoxins at the same level as the mycotoxin-low (MYC-L; 5.0 mg/kg DON, 2.1 mg/kg EA), and mycotoxin-high (MYC-H: 10 mg/kg DON, 4.2 mg/kg EA) diets that included wheat screening with mycotoxins. Steers were housed in individual pens for a 112-day finishing trial. Intake was 24.8% lower (P < 0.001) for MYC steers compared to CON steers. As a result, average daily gains of MYC steers were 42.1% lower (P < 0.001) than CON steers. Gain to feed ratio was also lower (P < 0.001) for MYC steers compared to CON steers. Platelets, alanine aminotransferase, globulins, and blood urea nitrogen were lower (P ≤ 0.008), and lymphocytes, glutathione peroxidase activity (GPx), and interleukin-10 (IL-10) were elevated (P ≤ 0.002) in MYC steers compared to CON steers. Hot carcass weights and backfat thickness were reduced (P < 0.001) in MYC steers, resulting in leaner (P < 0.001) carcasses and higher (P < 0.007) meat yield compared to CON steers. Results suggest that a mixture of DON and EAs negatively impacted health, performance, and carcass traits of feedlot steers, with the majority of this response likely attributable to EAs. However, more research is needed to distinguish the relative contribution of each mycotoxin to the specific responses observed.

Alkaloids in food: a review of toxicity, analytical methods, occurrence and risk assessments

Alkaloids have been utilized by humans for years. They have diverse applications in pharmaceuticals. They have been proven to be effective in treating a number of diseases. They also form an important part of regular human diets, as they are present in food items, food supplements, diet ingredients and food contaminants. Despite their obvious importance, these alkaloids are toxic to humans. Their toxicity is dependent on a range of factors, such as specific dosage, exposure time and individual properties. Mild toxic effects include nausea, itching and vomiting while chronic effects include paralysis, teratogenicity and death. This review summarizes the published studies on the toxicity, analytical methods, occurrence and risk assessments of six major alkaloid groups that are present in food, namely, ergot, glycoalkaloids, purine, pyrrolizidine, quinolizidine and tropane alkaloids.

Access to the CNS: Biomarker Strategies for Dopaminergic Treatments

Despite substantial research carried out over the last decades, it remains difficult to understand the wide range of pharmacological effects of dopaminergic agents. The dopaminergic system is involved in several neurological disorders, such as Parkinson's disease and schizophrenia. This complex system features multiple pathways implicated in emotion and cognition, psychomotor functions and endocrine control through activation of G protein-coupled dopamine receptors. This review focuses on the system-wide effects of dopaminergic agents on the multiple biochemical and endocrine pathways, in particular the biomarkers (i.e., indicators of a pharmacological process) that reflect these effects. Dopaminergic treatments developed over the last decades were found to be associated with numerous biochemical pathways in the brain, including the norepinephrine and the kynurenine pathway. Additionally, they have shown to affect peripheral systems, for example the hypothalamus-pituitary-adrenal (HPA) axis. Dopaminergic agents thus have a complex and broad pharmacological profile, rendering drug development challenging. Considering the complex system-wide pharmacological profile of dopaminergic agents, this review underlines the needs for systems pharmacology studies that include: i) proteomics and metabolomics analysis; ii) longitudinal data evaluation and mathematical modeling; iii) pharmacokinetics-based interpretation of drug effects; iv) simultaneous biomarker evaluation in the brain, the cerebrospinal fluid (CSF) and plasma; and v) specific attention to condition-dependent (e.g., disease) pharmacology. Such approach is considered essential to increase our understanding of central nervous system (CNS) drug effects and substantially improve CNS drug development.

Ergot Alkaloids in Fattening Chickens (Broilers): Toxic Effects and Carry over Depending on Dietary Fat Proportion and Supplementation with Non-Starch-Polysaccharide (NSP) Hydrolyzing Enzymes

Ergot alkaloids (EA) are mycotoxins produced by Claviceps purpurea. EA-toxicity is poorly characterized for fattening chickens. Therefore, a dose-response study was performed to identify the lowest, and no observed adverse effect levels (LOAEL and NOAEL, respectively) based on several endpoints. Non-starch-polysaccharide (NSP) cleaving enzyme addition and dietary fat content were additionally considered as factors potentially influencing EA-toxicity. Feed intake was proven to respond most sensitively to the EA presence in the diets. This sensitivity appeared to be time-dependent. While LOAEL corresponded to a total dietary EA content of 5.7 mg/kg until Day 14 of age, it decreased to 2.03 mg/kg when birds were exposed for a period of 35 days. Consequently, NOAEL corresponded to an EA content of 2.49 mg/kg diet until Day 14 of age, while 1.94 mg/kg diet applied until Day 35 of age. Liver lesions indicating enzyme activities in serum were increased after 14 days of exposure. Dietary fat content and NSP-enzyme supplementation modified EA toxicity in an interactive manner. The EA residues in serum, bile, liver and breast meat were <5 ng/g suggesting a negligible carry over of intact EA.

Effects of ergot alkaloids on liver function of piglets as evaluated by the (13)C-methacetin and (13)C-α-ketoisocaproic acid breath test

Ergot alkaloids (the sum of individual ergot alkaloids are termed as total alkaloids, TA) are produced by the fungus Claviceps purpurea, which infests cereal grains commonly used as feedstuffs. Ergot alkaloids potentially modulate microsomal and mitochondrial hepatic enzymes. Thus, the aim of the present experiment was to assess their effects on microsomal and mitochondrial liver function using the ¹³C-Methacetin (MC) and ¹³C-α-ketoisocaproic acid (KICA) breath test, respectively. Two ergot batches were mixed into piglet diets, resulting in 11 and 22 mg (Ergot 5-low and Ergot 5-high), 9 and 14 mg TA/kg (Ergot 15-low and Ergot 15-high) and compared to an ergot-free control group. Feed intake and live weight gain decreased significantly with the TA content (p < 0.001). Feeding the Ergot 5-high diet tended to decrease the 60-min-cumulative ¹³CO₂ percentage of the dose recovery (cPDR₆₀) by 26% and 28% in the MC and KICA breath test, respectively, compared to the control group (p = 0.065). Therefore, both microsomal and mitochondrial liver function was slightly affected by ergot alkaloids.

Bromocriptine inhibits adipogenesis and lipogenesis by agonistic action on α2-adrenergic receptor in 3T3-L1 adipocyte cells

The primary goals of the present study were to investigate the inhibitory effects of bromocriptine (BC) on adipogenesis and lipogenesis in 3T3-L1 adipocyte cells as well as to elucidate its molecular mechanism of action. Adipogenic and lipogenic capacity of BC-treated cells was evaluated by oil red-O staining, triglyceride content assay, real-time RT-PCR and immunoblotting. To determine the mechanism responsible for the anti-obesity effect of BC, we applied two methods. Firstly, we knocked down dopamine D2 receptor (D2R) up to 50% using siRNA. Secondly, we blocked the activity of α2-adrenergic receptor (α2-AR) by yohimbine treatment and monitored its effects on adipogenic and lipogenic events in 3T3-L1 cells. BC decreased the expression levels of adipogenic activators, including Pparα, Pparγ, and Cebpα, as well as major lipogenic target genes, including Me1, Acc1, 6Pgd, Fasn, and Prkaa1. Moreover, BC markedly reduced intracellular nitric oxide formation in a dose-dependent manner and expression of pro-inflammatory genes, Tnfα and Il6, which reflects attenuated pro-inflammatory responses. Further, upon treatment with BC, D2R-deficient cells displayed a significant decrease in lipogenic activity compared to control cells, whereas yohimbine-treated cells exhibited no reduction in lipogenic activity. BC can effectively attenuate adipogenesis and lipogenesis in 3T3-L1 cells by downregulating the expression of lipogenic genes and proteins. Our current experimental data collectively establish that the anti-obesity effects of BC are not D2R-dependent but result from the action of α2-AR in 3T3-L1 adipocytes.

Effects of ergot alkaloids on liver function of piglets can be detected by the [(13)C]methacetin breath test irrespective of oral or intramuscular route of tracer administration

Ergot alkaloids (sum=total alkaloids, TA) originate from the phyto-pathogenic fungus Claviceps purpurea and might exert feed intake depressing and hepatotoxic effects on animals. The aim of the study was to evaluate TA effects on performance and liver function of piglets with the [(13)C]methacetin breath test and two routes of tracer administration (orally, p.o.; intramuscularly, i.m.). Two ergot batches were mixed into piglet diets resulting in 21 and 17 mg TA kg(-1) (Ergot-5 and -12, respectively) and compared with an ergot-free control diet. Feed intake was significantly depressed after feeding the ergot containing diets (p=<0.001). The time at maximum (13)CO(2) exhalation (t (max)) and the half-life (t (0.5)) were not influenced by treatments and varied between 25 and 68 min after the p.o., and 28 and 62 min after the i.m. administration of [(13)C]methacetin, respectively. The cumulative (13)C recovery (cPDR(30)) was significantly lower due to feeding the diet Ergot-5 (6.6 %) compared with the Ergot-12 (8.8 %) and the control diet (9.7 %) irrespective of the route of tracer administration (p=0.044). As a discrimination of the diet effects through both tracer administration routes is possible, the i.m. application should be preferred in piglets as this causes less stress than the oral forced administration.

Relation between statistics and treatment-related changes obtained from toxicity studies in rats: if detected a significant difference in low or middle dose for quantitative values, this change is considered as incidental change?

The purpose of a toxicity test is to determine the no-observed-effect level (NOEL) of test substance through biological and pharmacological techniques. If the low dose not does show statistically significant and biologically relevant changes in the data evaluated in a study, the usual practice is to consider this dose as the NOEL. To overcome this, 6 types of techniques that seemed to be appropriate are presented in this paper by investigating the results of several domestic and foreign theses on toxicology. The most appropriate techniques appear to be the trend test, comparison between treatment group and historical control by t-test, and confirmation that all individual values lie within the 95% confidence interval (2 SD) of the historical control value, if a significant difference is admitted in the low dose.

Effect of fescue toxicosis on hepatic gene expression in mice1

Fescue toxicosis affects wild and domestic animals grazing fescue pasture infected with the endophytic fungus Neotyphodium coenophialum. Signs of fescue toxicosis include increased core body temperature and respiration rate and decreased milk yield and reproductive performance. Laboratory mice also exhibit symptoms of fescue toxicosis, as indicated by reduced growth rate and reproductive performance. Mice were used to study the effects of fescue toxicosis on hepatic gene expression. Twenty-seven mice were randomly allocated to a diet containing either 50% endophyte-infected (E+; 6 ppm ergovaline) or endophyte-free (E-) fescue seed for 2 wk under thermoneutral conditions. Liver genes differentially expressed due to fescue toxicosis were identified using DNA microarray. A 2-stage ANOVA of microarray data identified 36 differentially expressed genes between mice fed E+ and E- diets. Another analysis method, significance analysis of microarray, identified 9 genes as differentially expressed between treatment groups, and some genes overlapped with genes identified by ANOVA. Hierarchical clustering of 36 genes identified by ANOVA clearly separated the mice by diet, with 100% confidence as computed by bootstrap analysis. Expression of 11 genes was verified using quantitative real-time PCR. The E+ diet resulted in downregulation of genes involved in the sex-steroid metabolism pathway and genes involved in cholesterol and lipid metabolism. Genes coding for ribosomes and protein synthesis were upregulated by the E+ diet. Genes identified in the present analysis indicate some of the mechanisms by which fescue toxicosis occurs in animals.

Investigation of the effects of patulin on thyroid and testis, and hormone levels in growing male rats

Patulin is a mycotoxin produced by several species of Penicillium, Aspergillus and Byssachlamys. Patulin can be produced on different food products including fruits, grains, cheese, cured meats, but in natural situations patulin is usually found in apple and apple products. In the present study, the time-dependent effects of patulin on the T3, T4, thyroid stimulating hormone, testosterone, luteinizing hormone and growth hormone levels of growing male rats were investigated. Patulin, at a dose of 0.1 mg/kg bw/day, was administered by gavage to growing male rats aged 5-6 weeks for a period of 60 or 90 days. The dose of patulin used in the present study was based on estimated human exposure levels. At the end of the experiment, serum T3, T4, TSH, testosterone, LH and GH levels of rats in control and treatment groups were analysed. In addition, the thyroid and testes were histopathologically examined by light microscopy. Results revealed that while patulin caused an increase (66.6%) in testosterone levels and a decrease (17.3%) in T4 levels of rats treated for 60 days, there was no change in the other hormone levels compared to those of the control group. When patulin treatment was extended to 90 days, increased serum testosterone (75%) and LH levels (146%) were observed. In histological examinations of the testes of rats treated with patulin, oedema, fibrosis and local Leydig cell hyperplasia in the interstitial tissue, and disorganization of seminiferous tubule epithelium were also observed. In addition, the thyroid of rats treated with patulin revealed lymphoid cell inflitration and enlargement of interstitial tissue between follicles, and degenerated colloid.

Subacute toxicity of alpha-ergocryptine in Sprague-Dawley rats. 1: general toxicological effects

The dietary subacute toxicity of the ergot alkaloid alpha-ergocryptine was studied in Sprague-Dawley rats. Rats were fed 0, 4, 20, 100 or 500 mg ergocryptine/kg diet for 28-32 days (equal to 0, 0.36, 1.7, 8.9 and 60 mg ergocryptine/kg body weight/day for females and 0, 0.34, 1.4, 6.6 and 44 mg ergocryptine/kg body weight/day for males). The present study describes the general toxicological effects; the effects on metabolic and hormonal parameters will be reported separately. Body weight, body weight gain, food intake and food efficiency were all decreased with a U-shaped dose-response curve, as in both sexes the ranking severity of effects was in the order 100-20-500 and 4 mg/kg diet. Other changes with a U-shaped dose-response relationship included: hematological parameters (decreased MCV and MCH), serum enzyme activities (slightly increased/decreased ALAT, ASAT, GGT), increased serum urea concentrations, decreased glomular filtration (creatinine and urea clearances), decreased absolute organ weights, increased and decreased relative organ weights, atrophy of thymus and in females atrophy of ovary and uterus with in the mid-dose groups no detectable morphological features of an oestric cycle in the uterus. Other parameters, including increased relative liver, heart and ovarian weights and necrosis of the tail, were influenced in a dose-related manner or only in the high dose group. The U-shaped changes for the parameters mentioned above might be caused by the U-shaped dose-response relationship for food intake, which may be explained by the dopaminergic properties of alpha-ergocryptine. It is concluded that in rats fed ergocryptine for 28 days the dose-effect curve is rather steep and that the NOAEL is 4 mg/kg diet.