Danicke S., D. Gädeken, K.-H. Ueberschar, U. Meyer and H. Scholz

An experiment was carried out to examine the effects of a Fusarium-contaminated wheat (10 mg deoxynivalenol and 0.76 mg zearalenone, ZON, per kg dry matter) on fattening performance and slaughter yields of growing bulls, and on carry over of ZON into tissues and body fluids. In a second study, rumen physiological parameters were investigated in wethers equipped with a rumen fistulae. Moreover, the influences of a detoxifying agent (Mycofix®Plus, MP, Biomin GmbH, Herzogenburg, Austria) were considered as an additional experimental factor beside the contamination of the wheat (uncontaminated control wheat, Fusarium-toxin contaminated wheat). The experiments were designed according to a complete two by two factorial model of ANOVA which required the testing of both the control diet and of the contaminated diet either in the absence or presence of MP.
The fattening experiment with bulls (n=14 per treatment) covered the live weight range between 244 kg and 460 kg. The respective wheat batches were included in the concentrate portion at 64 %. Concentrates were fed restrictively whereas maize silage was offered for ad libitum consumption. Daily dry matter intake and live weight gain (kg per animal and day) were 7.40, 7.52, 7.51 and 7.49 and 1.367, 1.296, 1.380 and 1.307 for bulls fed the unsupplemented control wheat, the supplemented control wheat, the unsupplemented and Fusarium toxin contaminated wheat and the supplemented Fusarium toxin contaminated wheat, respectively. Feeding of the Fusarium toxin contaminated wheat resulted in a reduced dressing percentage, an increased weight of the emptied gastro-intestinal tract and a reduced weight of the testicles. No MP-effects were seen for these parameters. ZON or its metabolites were not detected in edible tissues.
The rations for wethers were composed of hay and of the respective wheat batch at a ratio of 1 to 1 on a dry matter basis. The results of the rumen physiological parameters revealed that the molar ratios of short chained volatile fatty acids and ammonia concentration in rumen fluid remained unchanged in response to dietary treatments whereas the addition of MP to the diets buffered the postprandial decrease in rumen pH. This effect was independent of the mycotoxin contamination of the wheat. The pH-differences in rumen fluids collected from wethers fed the MP-supplemented and unsupplemented rations amounted 0.2 to 0.3 on average in the time period between 1.5 h and 5 h after feeding. The kinetic profile of the in sacco dry matter degradation indicated a reduced degradation velocity for wheat straw incubated in wethers fed the mycotoxin contaminated rations whereas no changes were obvious when alfalfa hay was incubated. MP had no effect on the kinetics of dry matter degradation.

Kiyothong, K., P. Rowlinson, M. Wanapat and S. Khampa

A total mixed ration (TMR) containing a blend of feedstuffs naturally contaminated with harmful mycotoxins was fed for 84 days to 24 primiparous and multiparous Holstein–Friesian × local dairy cows in a randomised complete block design. The dietary treatments consisted of a contaminated TMR diet plus various levels of the mycotoxin deactivator product (MDP) (0, 15, 30 or 45 g/head.day). Deoxynivalenol (DON), fumonisin B1 (FB1), zearalenone (ZON) and ochratoxin A (OTA) were found in the TMR at levels up to 720, 701, 541 and 501 μg/kg, whereas aflatoxin B1 (AfB1) and T-2 toxin (T-2) were found in the TMR at levels of 38 and 270 μg/kg, respectively. Rumen microbial ecology, ruminal volatile fatty acid (VFA) concentrations, ruminal microorganism populations, feed intake, total tract digestibility, milk yield, milk composition and serum immunoglobulin (Ig) concentrations were measured. The results revealed that the ruminal pH, ruminal ammonia nitrogen (NH3-N) concentration, total ruminal VFA concentrations and ruminal bacterial counts were significantly (P < 0.05) higher in supplemented than in non-supplemented cows. Ruminal protozoal counts were significantly (P < 0.05) lower in supplemented than in non-supplemented cows. DM intake, and digestibility of crude protein (CP) and neutral detergent fibre (NDF) were significantly (P < 0.05) higher in supplemented than in non-supplemented cows. Serum IgA concentrations were significantly (P < 0.05) higher in supplemented than in non-supplemented cows. Milk yield and milk protein were significantly (P < 0.05) higher in supplemented than in non-supplemented cows. On the basis of this experiment, it can be concluded that milk production and feed intake can be increased with the addition of MDP to cow diet in the presence of mycotoxins. These increases were accompanied by decreases in the negative effects of mycotoxins on rumen and immune function.

Pietri, A., T. Bertuzzi, G. Piva, E. M. Binder, D. Schatzmayr and I. Rodrigues

This study reports the results of an experiment, testing the aflatoxin B1 (AfB1) carry-over from naturally contaminated feed to the dairy cows’ milk in the absence and in the presence of a mycotoxin deactivating product-Mycofix® Plus (MPL). The study was carried out using 18 healthy animals divided into 3 homogeneous groups of 6 animals each. The experimental design was a 3x3 Latin square with three periods of 7 days each without washout periods. The treatments were: (1) control diet without MPL (CTR); (2) control diet with 20 g/cow/day of MPL (T1) and (3) control diet with 50 g/cow/day of MPL (T2). The diet was a Total Mixed Ration (TMR) and 1 kg of a naturally contaminated maize meal (AfB1 = 91.7 ± 4.4 μg kg-1) was included in the diet of each cow. Each animal ingested daily 97.3 μg kg-1 AfB1 since the analysis of the TMR before inclusion of the contaminated maize revealed however the presence of 0.24 μg kg-1 DM of AfB1, corresponding to 5.6 μg per cow per day. In T1 and T2 diets, MPL was mixed with the contaminated maize meal. Feed intake and individual daily milk production were recorded during the study. Morning and evening milk samples from each cow were collected on day seven of each week. Samples derived from individual cows were mixed in proportion to the morning and evening milk production and then again combined in proportion to the daily milk production of each cow to constitute a representative bulk milk sample of each group; these samples were analyzed to determine the aflatoxin M1 (AfM1) content. The addition of MPL did not influence feed intake and milk production. The addition of MPL to the diet reduced significantly (p<0.01) the milk AfM1 content from 0.120 μg kg-1 (CTR group) to 0.083 μg kg-1 (-31%, T1 group) and 0.072 μg kg-1 (-41%, T2 group).

Reed K. F. M., A F, L. J. Cummins, D. D. Moore and A. J. Clark

During February–April, Coopworth ewe lambs grazing a pasture dominated by naturalised perennial ryegrass (PRG) exhibited slight signs of ill-thrift and heat stress. PRG represented 85% of the herbage; 90% of the PRG population was infected with Neotyphodium endophyte. Concentrations of ergovaline and lolitrem B in perennial ryegrass were each within the range 0.5–1.0 mg/kg DM during this period. Two groups of 30 lambs rotated weekly between two paddocks that offered 6 t DM/ha of mature, low-quality pasture. They received an allowance of crushed barley and peas (80 : 20) at 100 g/head per day. One group was treated with a mycotoxin deactivator, Mycofix® Plus, mixed into their mash during processing (5 g/100 g). No sign of ‘staggers’ was observed in the lambs at any time. Lambs with access to Mycofix Plus made great use of shade; their occupancy of shade increased steeply with ambient temperature over the range 18-38°C (P < 0.001). For the control group, occupancy of shade was low (P < 0.001) and independent of temperature (P < 0.001). Instead of using shade on hot days, the control lambs whose respiration rate was higher than treated ewes (P < 0.001) commonly stood by the wire fence, huddled in the open. Over the first 56 days of treatment, while pasture remained dry, weight change in control and treated lambs was –13 and +16 g/day, respectively (P < 0.010). The need for greater investigation of the effects of endophyte alkaloids on livestock is discussed.

K. F. M. Reed, J. L. Vaughan, L. J. Cummins, D. D. Moore

Liveweight gain, animal health and the effectiveness of a mycotoxin deactivator were studied on an old pasture that contained 61% perennial ryegrass. Sixty-seven percent of the ryegrass population was infected with endophyte (Neotyphodium spp.). The pasture was fenced into two halves and two groups of 28 alpaca male weaners were rotated between the two plots. Nine to 10 Suris and 18–19 Huacayas were allocated to each group. One group was fed a concentrate supplement (100 g/head per day) and the other was fed the same supplement to which was added the toxin deactivator, Mycofix® Plus (5 g/100 g). Mean liveweight gain on the low-quality pasture over late summer and early autumn was not significantly (P > 0.05) different between the groups. For the control group it was 41 g/day but individual rates of gain ranged from 67 to 0 g/day, depending on the severity of signs of perennial ryegrass toxicosis (r = 0.82, P < 0.001). Liveweight gain was independent of neurotoxic signs in the Mycofix® Plus treated group. Ergovaline concentration in perennial ryegrass varied from 0.43 to a peak in early autumn (March) of 1.05 mg/kg. Mean urine lysergol alkaloid concentration peaked in mid-summer (January) at 109 ng/mg creatinine (control group) and was consistently lower in the Mycofix® Plus group, although the difference approached significance (P = 0.06) only in March. Lolitrem B concentration in perennial ryegrass varied from 0.78 to 1.57 mg/kg. Neurotoxic signs in alpacas were observed throughout the study and peaked in early autumn, coinciding with peak lolitrem B concentration; at this time, 84% of alpacas exhibited neurotoxic signs. Over the 145-day study, the Mycofix® Plus treated group exhibited a lower mean rating of perennial ryegrass toxicosis signs (P < 0.05). Variation in liveweight gain and signs of toxicosis were not associated with significant differences in liver enzyme activity.