Influence of different dietary fibre contents in the diet on feather pecking, locomotor activity and performance of laying hens.

1. This study investigated the effects of three diets with increasing proportions of insoluble dietary fibre (3%, 6% and 9%) but with similar metabolisable energy on behaviour, plumage condition and laying performance of Lohmann Tradition hens.2. At 21 weeks of age, four groups of 20 hens each (= four replicates/treatment) were randomly assigned to one of the three feeding treatments and exclusively fed with their assigned feed until the end of the laying period.3. Severe feather pecking decreased with increasing fibre content (3%: 0.78 pecks/30 min/hen, 6%: 0.31, 9%: 0.12; P < 0.0001). In contrast, no effect of fibre was seen for gentle feather pecking (P = 0.19) and aggressive pecking (P = 0.84). The number of free feathers in the littered area increased with increasing fibre content (3%: 0.06 feathers/625cm2/hen, 6%: 0.09, 9%: 0.16; P = 0.0074). Over time, plumage quality worsened in all hens, but was consistently better with increasing fibre content (fibre content × sampling period; P < 0.0001). Locomotor activity was similar across all treatments, except for a slight decrease in hens fed the 3% fibre diet at the end of the experimental period. No effect of fibre content on hens' weight (P = 0.75) was detectable. Similarly, performance did not differ between hens fed varying dietary fibre.4. The results supported the assumption that increasing dietary fibre helps to reduce the risk for the occurrence of feather pecking in laying hens, i.e. improve well-being, while having no negative effects on performance.

Haematological and febrile response to Escherichia coli lipopolysaccharide in 12-week-old cockerels of genetically diverse layer lines fed diets with increasing L-arginine levels.

Due to its decisive function in the avian metabolic, endocrine and immune system L-arginine (Arg) is dietary indispensable for chickens. In 12-week-old cockerels of two high- and two low-performing purebred layer lines, the effects of increasing dietary Arg on the haematological and febrile response were studied over 48 h after single lipopolysaccharide (LPS) injection. The offered diets contained Arg equivalent to 70%, 100% and 200% of recommended supply. Pathophysiological alterations in weight gain, feed intake, body temperature and differential blood count were examined in comparison with their physiological initial values. Within the first 24 h after LPS injection, cockerels reduced feed intake and lost body weight subsequently. Thereby, low-performing genotypes lost body weight to a lesser extent than high-performing ones. The loss of body weight was further intensified by deficient dietary Arg. Within the following 24 h, cockerels recovered by improving feed intake and weight gain. Furthermore, LPS induced genotype-specific fever response: both brown genotypes showed initial hypothermia followed by longer lasting moderate hyperthermia, whereas the white genotypes exhibited biphasic hyperthermia. Fever response was accompanied by significant changes in differential blood counts. Characterized by lymphopenia and heterophilia, a severe leucopenia was observed from 4 to 8 h after LPS injection and replaced by a marked leucocytosis with longer lasting monocytosis up to 48 h after LPS injection. Under given pathophysiological conditions, deficiently Arg-supplied cockerels showed higher total leucocyte counts than adequately and excessively Arg-supplied cockerels. However, deficient and surplus dietary Arg tended to cause higher ratios between heterophils and lymphocytes. To conclude, present results confirmed that LPS induced numerous immunological changes in 12-week-old cockerels and emphasized that chicken's genotype is a source of variation to be considered for immunological studies. Deficient dietary Arg intensified acute changes in differential blood counts and weight gain during LPS-induced inflammation.

Metabolic and clinical response to Escherichia coli lipopolysaccharide in layer pullets of different genetic backgrounds supplied with graded dietary L-arginine.

L-arginine (Arg) is an essential amino acid in birds that plays a decisive role in avian protein synthesis and immune response. Effects of graded dietary Arg supply on metabolic and clinical response to Escherichia coli lipopolysaccharide (LPS) were studied over 48 hours after a single intramuscular LPS injection in 18-week-old genetically diverse purebred pullets. LPS induced a genotype-specific fever response within 4 hours post injectionem. Whereas brown genotypes showed an initial hypothermia followed by longer-lasting moderate hyperthermia, white genotypes exhibited a biphasic hyperthermia without initial hypothermia. Furthermore, within 2 hours after LPS injection, sickness behavior characterized by lethargy, anorexia, intensified respiration, and ruffled feathers appeared, persisted for 3 to 5 hours and recovered 12 hours post injectionem. The varying grades of Arg did not alter the examined traits named above, whereas insufficient Arg reduced body growth and increased relative weights of liver and pancreas significantly. At 48 hours post injectionem, increased relative weights of liver and spleen were also found in LPS treated pullets, whereas LPS decreased those of pancreas, bursa, thymus, and cecal tonsils. Moreover, LPS lowered the sum of plasma amino acids and decreased plasma concentrations of Arg, citrulline, glutamate, methionine, ornithine, phenylalanine, proline, tryptophan, and tyrosine, and increased those of aspartate, glutamine, lysine, 1- and 3-methyl-histidine. Elevating concentrations of dietary Arg led to increasing plasma concentrations of Arg, citrulline, ornithine, and 3-methyl-histidine subsequently. As quantitative expression of LPS-induced anorexia, proteolysis, and the following changes in plasma amino acids, pullets showed a significant decrease of feed and nitrogen intake and catabolic metabolism characterized by negative nitrogen balance and body weight loss in the first 24 hours post injectionem. Pullets recovered from the challenge within the second 24 hours post injectionem and changed to anabolism with re-increased feed and nitrogen intake, positive nitrogen retention, and weight gain. To conclude, present results confirmed that LPS induced numerous metabolic and physiological changes in pullet's genotypes, whereas dietary Arg affected the examined traits only slightly.

The effect of various iodine supplementations and two different iodine sources on performance and iodine concentrations in different tissues of broilers.

1. The objective of this study was to determine the influence of iodine (I) supplementation of feed, within the range of the European guidelines, on the performance of broiler chickens and I transfer into different organs and tissues, especially meat. The main emphasis was to assess whether broiler meat could be enriched and used as an I source in human nutrition. 2. Two experiments were performed, one with KI and the other with Ca(IO(3))(2). For each experiment, 288 d-old broiler chicks were divided into 4 groups (72 birds/group) and fed on diets with supplementations between 0 and 5 mg I/kg feed. The birds were reared to 35 d of age under standard conditions. Six birds per group were slaughtered at 35 d and samples of blood, thyroid gland, liver, pectoral and thigh meat taken. 3. Iodine treatment did not significantly affect the growth and slaughter performance of the broiler chickens. In all investigated parameters, I concentrations increased significantly with increasing I intake of the animals. The lowest I concentrations were measured in the meat, but they were considerably higher in blood serum, liver and thyroid gland. Since the I content of meat was still low in the highest supplemented group (highest median concentration: 67·8 µg I/kg thigh meat), there is no evidence that this could substantially improve I supply in human nutrition.

Effects of an active immunization on the immune response of laying Japanese quail (Coturnix coturnix japonica) fed with or without genetically modified Bacillus thuringiensis-maize.

Potentially adverse effects of diets containing transgenic plants are a concern for many consumers, particularly in Europe. For Bacillus thuringiensis-maize, several studies in livestock and poultry showed that the zootechnical data provide no indication for such adverse effects. These studies were all done in homeostatic situations; it remained open whether a deflection of the regulatory physiological systems might yield divergent dynamic responses in B. thuringiensis-maize-fed animals. We therefore tested the effect of an active immunization using BSA as antigen in a feeding regimen with or without B. thuringiensis-maize using quail as a model organism. Newly hatched Japanese quail were randomly allocated to 2 groups (n=120 per group) fed with diets containing either B. thuringiensis-maize or isogenic maize of the same cultivar. The diets did not differ in concentrations of the mycotoxins deoxynivalenol and zearalenone, which were both far below guidance values. After 16 wk on the experimental diets, one-half of each group was immunized against BSA. The remaining birds were injected with saline. Thirty-six hours after the injection, half of the BSA-injected subgroup (n=30) and half of the saline subgroup (n=30) from B. thuringiensis-maize- and isogenic-fed birds were killed and blood samples were collected and analyzed for serum zinc levels, indicative for acute phase response. For determining IgY-mediated immune responses, eggs were collected every other week for 6 wk after the injections from the remaining birds and total IgY concentrations and BSA-specific IgY titers were measured in egg yolk. The BSA injections did not elicit significant decreases of serum zinc concentrations. The serum zinc levels were significantly higher in B. thuringiensis-maize-fed quail. Expectedly, total IgY as well as BSA-specific IgY titers increased with time in the BSA-immunized quail. The response of both variables to the BSA injection did not differ between the feeding groups. Our results indicate that feeding of B. thuringiensis-maize does not impair the immune system of Japanese quail and thus gives no indication for respective concerns.

Influence of temperature stimulation during the last 4 days of incubation on secondary sex ratio and later performance in male and female broiler chicks.

1. In 6 incubation trials a total of 9883 eggs (Ross 308) were incubated from d 1 to 17 under normal incubation conditions (37.2-37.4 degrees C) and then sorted into three hatch incubators (control: 37.2-37.4 degrees C; chronic warm incubation: 38.2-38.4 degrees C, 24 h daily; short-term warm stimulation: 38.2-38.4 degrees C, 2 h daily) in incubation trials 1 and 2 or two hatch incubators (control and short-term warm stimulation) in trials 3-6. 2. The one-day-old chicks were selected by sex and chick quality was analysed in random samples using the Pasgar score. A total of 120 male and 120 female one-day-old chickens from each incubator were used for a 35-d fattening period. 3. Neither chronic nor short-term increase in incubation temperature had a negative effect on hatchability and chick quality. Short-term warm stimulation improved hatchability by more than 1.5% and was associated with a significantly higher proportion of hatched male chicks. 4. In the subsequent broiler growth trial, the mean daily weight gain of the short-term warm stimulated male broiler chicks was significant higher than for the control group, which results in a body weight increase of 2.9%. 5. Feed conversion (feed:gain ratio) of the short-term warm stimulated male and female broilers was significantly lower than in the males and females of the control and chronic warm incubated groups. 6. In conclusion, an incubation temperature profile which includes short-term temperature variation can be important in improving poultry performance (European patent pending since March 2008).

Serum chemistry reference values in adult Japanese quail (Coturnix coturnix japonica) including sex-related differences.

Serum chemistry reference values may provide useful information about the physical condition of individuals, making them a useful tool in differentiating normal and healthy animals from abnormal or diseased states. For Japanese quail that are used for producing eggs and meat for human consumption and also as laboratory animals, we aimed to extend the available array of reference values and to compare 16-wk-old adult male versus female birds. In the present study, clinical chemistry data (albumin, total protein, glucose, uric acid, cholesterol, bilirubin, cholinesterase, creatinine, triglycerides, alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyltransferase) in blood serum from up to 125 male and 151 female Japanese quail were established. Statistical comparisons were made between male and female birds. Aspartate aminotransferase, alanine aminotransferase, glucose, cholinesterase, and bilirubin values were higher (P < 0.01) in males, whereas females had higher (P < 0.05) concentrations of albumin, total protein, gamma-glutamyltransferase, total cholesterol, and triglycerides. No significant sex-based differences were observed for creatinine and uric acid. The reference values provided are relevant in particular for the use of quail as laboratory animals when responses to specific treatments have to be monitored and appraised.

Nutrient balances as indicators for sustainability of broiler production systems.

1. Flock balances of nitrogen, phosphorus, zinc and copper (N, P, Zn, Cu) were calculated in order to evaluate environmental effects of three different broiler production systems (intensive indoor, free range and organic). 2. Nutrient gain in birds per unit nutrient intake (retention) in intensive indoor production was higher than in free range and organic production. 3. Nutrient surplus relative to nutrient retention was higher in organic production than in free range and intensive indoor production. 4. The main reasons for differences in nutrient efficiency between intensive indoor, free range and organic production were duration of growth period, strain of broilers and feeding strategy. 5. The calculation of whole farm indicators (livestock density, N and P excretions per hectare of farmland) demonstrates how defining system boundaries affects the outcome of an evaluation: organic farms had the smallest livestock densities and the lowest N and P excretions per hectare of farmland. 6. In the efforts to reach a more holistic evaluation of agricultural production systems, the definition of adequate system boundaries must be discussed. In addition to nutrient balances, further indicators of sustainability, such as human and ecological toxicity, should be considered.

Effects of graded levels of Fusarium-toxin-contaminated wheat in Pekin duck diets on performance, health and metabolism of deoxynivalenol and zearalenone.

1. Diets with increasing proportions of Fusarium-toxin-contaminated wheat were fed to Pekin ducks for 49 d in order to titrate the lowest effect level. Dietary deoxynivalenol (DON) and zearalenone (ZON) concentrations were successively increased up to 6 to 7 mg/kg and 0.05 to 0.06 mg/kg, respectively. 2. Feed intake, live weight gain and feed to gain ratio were not influenced by dietary treatment. 3. Gross macroscopic inspection of the upper digestive tract did not reveal any signs of irritation, inflammation or other pathological changes. The weight of the bursa of Fabricius, relative to live weight, decreased in a dose-related fashion. Activities of glutamate dehydrogenase and gamma-glutamyl-transferase in serum were either unaffected or inconsistently affected by dietary treatments. 4. Concentrations of DON and of its de-epoxydised metabolite in plasma and bile were lower than the detection limits of 6 and 16 ng/ml, respectively, of the applied high performance liquid chromatography (HPLC) method. 5. ZON or its metabolites were not detectable in plasma and livers (detection limits of the HPLC method were 1, 0.5 and 5 ng/g for ZON, alpha-zearalenol (alpha-ZOL) and beta-zearalenol (beta-ZOL), respectively). Concentrations of ZON, alpha-ZOL and beta-ZOL in bile increased linearly with dietary ZON concentration. The mean proportions of ZON, alpha-ZOL and beta-ZOL of the sum of all three metabolites were 80, 16 and 4%, respectively. 6. Taken together, it can be concluded that dietary DON and ZON concentrations up to 6 and 0.06 mg/kg, respectively, did not adversely affect performance and health of growing Pekin ducks.

Safety assessment of Bt 176 maize in broiler nutrition: degradation of maize-DNA and its metabolic fate.

Insect resistant Bt 176 maize has been developed by genetic modification to resist European borer infection. In the present investigation, the experiment was conducted to determine the effect of feeding a new hybrid of Bt 176 maize (NX 6262- Bt 176) on general health condition and performance of broiler chickens. Maize grains and diets were subjected to proximate analysis. Amino and fatty acids investigation were applied for both maize grains before used. To evaluate the degradation of NX 6262- Bt 176 maize DNA and its metabolic fate in broiler blood, muscles and organs. One-day-old male broilers were fed ad libitum on either an experimental diet containing NX 6262- Bt 176 or a control diet containing the non-modified maize grains for 35 days. Feed consumption and body weight were recorded weekly during the experimental period. All chickens were subjected to nutritional evaluation period at day 20 of age for 5 successive days, to calculate the percentage of apparent digestible nutrients in both diets. At day 35 samples were collected at several intervals after feed withdrawal. Prior to slaughter blood samples were collected from all birds by heart puncture to prevent DNA cross contamination. Samples from pectoral and thigh muscles, liver, spleen, kidney, heart muscle, bursa and thymus glands were collected. Digesta from different sections of the gastrointestinal tract (GIT) were collected as well. Packed cell volume (PCV) and some serum parameters were investigated. There were no significant differences between control and experimental group concerning chemical composition of feeds, apparent digestible nutrients, and all performance parameters measured (P > 0.05). Furthermore, there were no differences in the PCV and the analysed serum parameters between the control and experimental group. The results of maize DNA digestibility showed that the new variety takes the normal physiological passage along broiler GIT similar to the conventional line. In addition, Bt 176 maize DNA appears to be partially degraded in different parts of GIT comparable to the DNA of the control maize line. Results of the metabolic fate of maize DNA in broiler blood, muscles and organs indicated that only short DNA fragments (199 bp) derived from the plant chloroplast gene could be detected in the blood, skeletal muscles, liver, spleen and kidney, which disappeared after prolongation the fasting time. In heart muscle, bursa of Fabricius and thymus, no plant chloroplast DNA was found. Bt gene specific constructs from Bt 176 maize were not detected in any investigated blood or tissue samples.

Effects of graded levels of Fusarium toxin-contaminated wheat and of a detoxifying agent in broiler diets on performance, nutrient digestibility and blood chemical parameters.

1. A growth experiment was carried out with male broilers from d 1 to d 35 of age in order to evaluate the effects of the addition of a detoxifying agent (Mycofix Plus, Biomin GmbH, Herzogenburg, Austria) at different dietary proportions of wheat (0, 16.5, 33, 49.5 and 66%) contaminated with Fusarium mycotoxins (21.2 mg of deoxynivalenol and 406 microg of zearalenone, ZON, per kg of wheat) on growth performance, nutrient and zearalenone balance and clinical-chemical parameters. 2. An increase in dietary mycotoxin concentration resulted in a linearly related decrease in feed intake, a slight decrease in weight gain and an improvement in feed to gain ratio. 3. Apparent protein digestibility and net protein utilisation were higher in diets containing exclusively Fusarium toxin-contaminated wheat than control diets. 4. The proportions of beta-zearalenol, alpha-zearalenol and ZON of total ZON metabolites in excreta of broilers fed on the diets containing the Fusarium toxin-contaminated wheat were approximately 3, 21 and 76%. 5. Serum antibody titres to Newcastle disease virus decreased in a linear fashion with increasing mycotoxin concentration in the diets, whereas other clinical-chemical serum parameters (liver cell and muscle cell necrosis indicating enzymes, haemoglobin, haematocrit, magnesium, inorganic phosphate) were not influenced by increasing Fusarium toxin concentrations. 6. Supplementation of the diets with Mycofix Plus decreased performance in a manner independent of mycotoxin concentration. Moreover, some clinical-chemical serum parameters were significantly altered due to Mycofix Plus but also independently of the dietary mycotoxin concentration.

Effect of addition of a detoxifying agent to laying hen diets containing uncontaminated or Fusarium toxin-contaminated maize on performance of hens and on carryover of zearalenone.

16-wk experiment with laying hens was carried out to examine the effects of feeding of mycotoxin-contaminated maize (CM) on performance, nutrient digestibility, weight of organs, serum chemical parameters, and antibody titers to Newcastle disease virus (NDV) in serum. Also tested were fimbrien antigen K88 in egg yolk and zearalenone (ZON) residues in eggs and tissues. The Fusarium-toxin-contaminated maize contained 17,630 microg deoxynivalenol and 1,580 microg ZON/kg. Moreover, Mycofix Plus (MP), a so-called detoxifying agent, was added to both the uncontaminated control (UCM) and to the CM diet (70% dietary maize inclusion). Each of the four resulting diets (UCM, UCM-MP, CM, CM-MP) was tested on 25 laying hybrids (Lohmann Brown). Feeding of the CM diets significantly depressed feed intake compared to the control groups by approximately 5%. This was mainly due to the effects observed at the beginning of the experiment. Daily egg mass production/hen was 56.6, 58.4, 53.9, and 55.2 g in groups UCM, UCM-MP, CM and CM-MP, respectively. Nutrient digestibility and metabolizability of gross energy were slightly depressed by feeding the CM diets and improved by MP addition. Feeding of the CM diets resulted in a significant decrease in serum titers to NDV and to an increase in yolk titers to antigen K88. No residues of ZON or of its metabolites were found in yolk, albumen, abdominal fat, breast meat, follicles greater than 1 cm in diameter, ovaries including follicles smaller than 1 cm in diameter, magnum, and serum. ZON and alpha-zearalenol (alpha-ZOL) were detected in livers of hens fed the CM diets at mean concentrations of 2.1 and 3.7 microg/kg, respectively. It was concluded that feeding maize which was highly contaminated with Fusarium mycotoxins adversely influenced performance of hens and modulated immune response. At the given level of zearalenone and at the indicated detection limits, no residues of ZON and its metabolites were found in eggs. The effects of the tested detoxifying agent were quite mycotoxin-independent.

Influence of high levels of vitamin E on semen parameters of cocks.

This study was an attempt to find whether the reproductive performance of cocks would be influenced by oral administration of different amounts of dietary vitamin E over a long period of time. For that purpose 60 cocks were divided into five dietary groups of 12 animals each, and supplemented with 0 (control group), 100, 1,000, 10,000 or 20,000 IU alpha-tocopherol/kg diet, respectively, over a period of 12 months. The effect on semen parameters and biochemical parameters measured in pooled semen samples and the weight of the testes were determined. The weight of testes decreased with increasing amounts of supplemented vitamin E. Volume, pH, colour, consistency and motility were not influenced by the diets, but density of ejaculate (sperm/microl), total amount of spermatozoa and morphology of sperm were significantly lowered by increasing amounts of supplemented vitamin E. The alpha-tocopherol concentration in ejaculates increased significantly in relation to the diet whereas phospholipid content and thiobarbituric acid-reactive substances (TBARS) of the semen samples decreased significantly with increasing vitamin E supplementation. The reproductive performance of cocks was negatively influenced by high doses of vitamin E although decreased TBARS indicated rising oxidative defence.

Effect of energy source and xylanase addition on energy metabolism, performance, chemical body composition and total body electrical conductivity (TOBEC) of broilers.

Three diets containing either no supplemented fat (LF), 12% soybean oil (SO) or 12% coconut oil (CO) were fed to broilers to examine energy utilization in two experiments. Heat production and energy retained as fat and protein were measured in the first experiment using a respiration technique in combination with C- and N-balance and controlled (pair-fed) feeding conditions. Growth performance, carcass composition, chemical body composition and total body electrical conductivity (TOBEC) were evaluated in a second experiment under ad libitum feeding conditions (from hatching to day 35). Moreover, each of the three diet types was tested with or without the addition of a xylanase-containing enzyme preparation in the growth experiment. Energy utilization (experiment 1), expressed as the ratio between total retained energy and metabolizable energy intake, amounted to 0.33, 0.36 and 0.39 in LF-, SO- and CO-fed groups, respectively. Applying ad libitum feeding conditions in the second experiment caused a significant reduction in feed intake and weight gain in broilers fed the CO-diet. The feed-to-gain ratio was significantly lower in birds given the fat-supplemented diets. The highest degree of fatness as indicated by the highest percentage of abdominal and visceral fat and by highest total fat content was found in birds fed the CO-diet. The higher the body protein content and the lower the body fat content, the higher the TOBEC value should be. This was confirmed when LF-fed broilers were compared to their CO-fed counterparts. However, fat type seemed to be related to TOBEC values since SO-fed broilers had similar TOBEC values as CO-fed birds, whereas chemical body composition was comparable to LF-fed broilers. Xylanase addition significantly increased weight gain up to 21 days of age and decreased the feed-to-gain ratio slightly, whereas none of the other parameters were influenced by this treatment. An interaction between energy source and enzyme supplementation was not observed. It is concluded that feeding of coconut oil was most effective in terms of energy retention, but failed to induce an adequate performance under ad libitum feeding conditions due to a reduced voluntary feed intake. TOBEC measurements in relation to chemical body composition were rather inconclusive.

Effects of feeding high dosages of vitamin E to laying hens on thyroid hormone concentrations of hatching chicks.

Long-term experimental feeding of 20,000 ppm alpha-tocopheryl acetate to laying hens caused a significant (P < 0.05) decrease in hatching rates as compared to the control group, which was fed a diet containing 19 ppm alpha-tocopherol. When the thyroid hormones in the developing chicks were checked on incubation days 16, 19, 21, and 22, the following results were ascertained: During the latter part of incubation, increases in plasma concentrations of thyroxine and triiodothyronine were observed. No significant differences in hormone concentrations (P > 0.05) between the control and the treatment group were observed during incubation days 16, 19, and 22. However, on the day of hatching (day 21 of incubation) significantly lower (P < 0.05) triiodothyronine concentrations in chick embryos of piped eggs were found in the treatment group. Moreover, thyroxine concentrations in non-piped eggs and in hatched chicks were found to be significantly higher as compared to the control group. Given these results, one concludes that extremely high dosages of vitamin E may affect thyroid hormone concentrations of hatching chicks, and therefore, the chicks might be inhibited in pipping the egg shell. Hypothetically, the hepatic enzyme 5'-monodeiodinase is involved in the mechanism of inhibition.

Genetically modified feeds in animal nutrition. 1st communication: Bacillus thuringiensis (Bt) corn in poultry, pig and ruminant nutrition.

During the last few years, animal nutrition has been confronted with genetically modified organisms (GMO), and their significance will increase in the future. The study presents investigations on the substantial equivalence of the transgenic Bt (Bacillus thuringiensis) corn and the corresponding nontransgenic hybrid Cesar and parameters of nutrition physiology such as digestibility and energy content for poultry, pigs and ruminants. The results of the analysed corn samples as well as of the silage samples illustrated substantial equivalence in all investigated ingredients, such as crude nutrients, amino acids, fatty acids, minerals and non-starch polysaccharides. The results of the experiments using poultry, pigs, wethers and fattening bulls were not influenced by the genetic modification of corn. The determined values for the digestibilities and the energy contents for poultry, pigs and wethers were not affected by the used corn variety. Neither the examined parameters of the fattening experiments with bulls nor the slaughter results showed any significant differences between the bulls fed on silages made from the nontransgenic or transgenic corn.

Excretion kinetics and metabolism of zearalenone in broilers in dependence on a detoxifying agent.

Two experiments were carried out with male broilers to examine excretion kinetics of zearalenone (ZON) and its metabolites and their occurrence in blood plasma and bile fluid after a single oral dose of ZON (approximately 6 micrograms/kg BW) from naturally contaminated wheat (406 micrograms ZON per kg). In addition, this ZON bolus was administered either in the absence or presence of a detoxifying agent (Mycofix-Plus, Biomin GmbH, Herzogenburg, Austria). Specimens were sampled after administration of the zearalenone bolus at different times of up to 48 h. Excretion of zearalenone and alpha-zearalenol as the only detectable metabolite of ZON peaked at approximately 6.5 h after administration of the bolus. Cumulative excretion of both substances amounted to approximately 58% of ZON intake after 48 h, when a plateau was achieved. The incomplete recovery could have been due to a partial total degradation of ZON in the digestive tract, undetected sulfate conjugates of ZON or its metabolites, to other unknown and undetected metabolites or to incomplete analytical recovery from the matrix, and needs to be examined further. Peak concentrations of zearalenone and alpha-zearalenol in bile were detected in the time period of approximately 2 to 6 h after bolus, whereas ZON and metabolite concentrations in blood plasma were around or lower than the detection limits. Mycofix-Plus supplementation seemed to have only minor or no effects on the parameters examined.

On the effects of Fusarium toxin contaminated maize in laying hen feeding.

The effects of feeding a Fusarium toxin contaminated maize (CM) to laying hens were studied in a 16-week lasting experiment. The CM contained 17630 µg deoxynivalenol (DON) and 1580 µg zearalenone (ZON) per kg.Animal performance, serum chemical parameters, antibody titers to Newcastle disease virus (NDV) in serum, antibody titers to fimbrien antigen K88 in egg yolk, and ZON residues in eggs and tissues were investigated.Moreover, Mycofix® Plus (MP), a so-called detoxifying agent, was added both the non-contaminated control (M) and to the CM diet. Each of the four resulting diets (M, M-MP, CM, CM-MP) was tested on 25 laying hybrids (Lohmann Brown).Hens fed the CM- and the CM-MP diet had a significantly depressed feed intake compared to the control groups of about 5 percent, mainly due to the effects observed at the beginning of the experiment.Daily egg mass production per hen was 56.6 g, 58.4 g, 53.9 g and 55.2 g in groups M, M-MP, CM and CM-MP, respectively. The main factors (maize contamination, MP-addition) were significant, whereas interactions were insignificant, suggesting a mycotoxin-independent effect of MP.Feeding of the CM-diets resulted in a significant decrease in serum titers to NDV and to an increase in yolk titers to antigen K88.No residues of ZON or of its metabolites were found in yolk, albumen, abdominal fat, breast meat, follicles greater than one cm in diameter, ovaries including follicles smaller than one cm in diameter, magnum or serum. ZON and α-zearalenol (α-ZOL) were detected in the livers of hens fed the CM-diets at mean concentrations of 2.1 µg/kg and 3.7 µg/kg, respectively.It was concluded that the feeding of maize highly contaminated with Fusarium mycotoxins adversely influenced performance of the hens and modulated immune response. At the given level of zearalenone and at the detection limits (0.5-2 µg/kg), no residues of ZON or its metabolites were found in eggs. The effects of the tested detoxifying agent were found to be independent of mycotoxins.

Investigations on metabolism of zearalenone in broilers.

Two experiments were carried out with male broilers to examine excretion kinetics of zearalenone (ZEA) and its metabolites (Exp. 1) and their occurrence in blood plasma and bile fluid (Exp.2) after a single oral dose of ZEA (approximately 6 µg/kg body weight) from naturally contaminated wheat. In addition, this ZEA bolus was administered either in absence or presence of a detoxifying agent (Mycofix® Plus, Biomin GmbH, Herzogenburg, Austria). Specimens were sampled at different times after ZEA bolus of up to 48 h. Excretion of ZEA and alpha-zearalenol as the only detectable metabolite of ZEA peaked at approximately 6.5 h after administration of the bolus. Cumulative excretion of both substances amounted approximately 58 % of ZEA intake after 48 h. Peak concentrations of ZEA and alpha-zearalenol in bile were detected in the time period of approximately 2 to 6 h after bolus whereas detection in plasma was not possible for each measurement point. Mycofix® Plus supplementation seemed to have only minor or no effects on the parameters examined.

Vitamin E hypervitaminosis in laying hens.

The aim of this investigation was to contribute to the problem of overdosing vitamin E. A total of 80 laying hens, divided into 5 groups, were fed diets supplemented with 0, 100, 1000, 10,000 and 20,000 mg/kg vitamin E over a period of 20 weeks within two brooding tests. Laying performance and hatching parameters were registered. All vitamin E doses did not significantly influence health and performances of hens. Vitamin E content of eggs increased from 1 to 4, 21, 46 and 51 mg per egg with vitamin E supplementation. High doses decreased oxidative stability of abdominal fat, vitamin A concentration of liver and egg yolk colour. In both tests vitamin E supplements of 10,000 and 20,000 mg/kg feed resulted in a decrease of living hatched chicken, which demonstrated an adverse effect. Further studies seem to be necessary to explain the effect.