Untersuchungen zum Einfluss von Mutterkornalkaloiden auf die Leistung und die Leberfunktion von Absatzferkeln

As an undesirable contaminant the sclerotium of Claviceps purpurea called ergot, there is not allowed to be more than 1 g/kg in feed grain. The toxicity of ergot is caused by several content substances in variable concentrations and compositions. Thereby the content of ergot alkaloids produced as second metabolites in the fungus plays an important role. The alkaloid pattern differs depending on environment and fungus strain. Aim: This study deals with investigations on the antinutrient effect of alkaloids contained in ergot which was fed in several concentrations on postweaning piglets. Materials and methods: Four feeding trials were conducted, each including a control group which received an uncontaminated diet. The total alkaloid concentration2 in the ergot varied with a range from 297 to 1381 mg/kg. The piglets were housed in pens with free access to feed and water three and five weeks respectively. The ergot-containing diets were formulated to contain similar total alkaloid concentrations. In all the trials, each had two ergot sources which had different alkaloid concentrations and patterns. Trial I and II were calculated to contain a total alkaloid concentration of 16,8 mg/kg. Diets with two graded concentrations of total alkaloids were used to determine a dose dependent effect in trial no. II (8,4 mg/kg and 16,8 mg/kg). In addition to the diets with similar alkaloid concentration (8,4 mg/kg), diets with similar ergot concentration were applied in trial no. IV (13,3 g/kg and 33,5 g/kg). The known isomerization of ine-isomers into inine-isomers after handling and the variability of total alkaloid content in the ergot were observed in the present study. The alkaloid concentration analysed in the diet is used below. Blood from a selection of all the piglets was collected, and the serum was tested for several liver parameters after three weeks. Furthermore, a 13C-methacetin breath test, as a liver function test, was performed. This test is widely used in human medicine for estimating liver clearance and severity of liver damage. 13C-methacetin was given at a dose of 2 mg/kg live weight, and breath samples were taken after 0, 15, 30, 45, 60, 90, 120, 180, 240, 300 and 360 minutes. Other than the mentioned effect of the different diet composition, the influence of the sex was tested. Additionally, the parameters of liver health status were collected after the first week in trial II to determine the effect of the period of exposure. The following results are summarised: Performance: Daily feed intake and daily weight gain were significantly lower in the piglets fed with ergot contaminated diets with total alkaloid content higher than 6 mg/kg compared with the control animals (average of the groups: -6 up to -56 % and -16 up to -108 % respectively). A general difference in performance parameter between the effects of different ergot sources couldn’t be proved. Diets with a total alkaloid concentration of about 20 mg/kg or an ergot concentration of about 5 % caused higher feed conversion in several trial periods. There was also a linear dose-dependent feed intake, weight gain and feed conversion in trial no. III. Whereas in the first week the difference between the percentage aberration of feed intake and weight gain was high, there was a convergence in the following weeks. Inconsistent effects of sex on performance parameters caused no diverse results. Serum parameters: The investigation of serum parameters showed inconsistent results, serum concentrations of protein an albumin decreased relative to the time of ergot exposure compared with the control piglets. Methacetin-breath test The highest 13CO2-Exhalation (DOBmax), the cumulative recovery after 30 min (cPDR30) and after 180 min (cPDR180) was mostly higher in the controls than in the piglets of the compared, ergot exposed, groups. The peak time (tmax) and the period of half 13CO2-Exhalation (t0,5) of the controls were lower. However significant differences only existed for tmax, DOBmax, cPDR30 and cPDR180 in trial IV. There were no consistent sexual effects on the methacetin-breath test. Interactions between sex and diet existed in trial II. The period of exposure in trial II had only a significant influence on cPDR180. Conclusions: The estimation of the effect of alkaloid pattern on performance and liver health of postweaning piglets is difficult due to the variability of the alkaloid concentration. Overall in consideration of all the trials, the alkaloid pattern has no principal influence compared with the total alkaloid concentration. The sum of alkaloids is the most important parameter for estimating negative effects on performance. Other components like ricinoleic acid are also conductive to the reduced performance. The decreased weight gain is mainly caused by reduced feed intake. Impairment of liver health by ergot alkaloids couldn’t be proved because other factors such as an influence of reduced feed intake and growth on liver parameters especially the methacetin breath test could not be ruled out. Anyhow, the defined limit of alkaloids in feed should involve an assessement factor including possible toxicological potential of all critical compounds. 2 containing ergometrine, ergotamine, ergocornine, ergocryptine, ergocristine, ergosine and their inine-isomers