Effects of Increasing Supplementation of Magnesium in Diets on Productive Performance and Eggshell Quality of Aged Laying Hens

Magnesium (Mg) concentrations in diets have been associated with performance and eggshell quality of laying hens, but the results have been inconclusive. In this experiment, the effects of increasing concentrations of dietary Mg on productive performance and eggshell quality of aged laying hens were evaluated. A total of 640 Hy-Line Brown laying hens of 72 weeks of age were randomly allotted to one of four dietary treatments with four replicates per treatment. A commercial-type basal diet containing 1.6 g/kg Mg was prepared, and three additional diets were prepared to contain 2.3, 2.6, or 3.0 g/kg Mg in diets by adding 1.0, 1.5, or 2.0 g of MgO to the basal diet. The diets were fed to hens ad libitum for 5 weeks. Results indicated that Mg concentrations in eggshells were increased (linear, P?<?0.01) with increasing concentrations of Mg in diets. Increasing concentrations of Mg in diets decreased (linear and quadratic, P?<?0.01) broken and shell-less egg production, but improved (linear, P?<?0.05) eggshell strength. Feed intake was decreased (linear, P?<?0.05) with the concentrations of Mg in diets, but hen-day egg production, egg weight, feed conversion ratio, and Haugh unit were not affected by increasing concentrations of Mg in diets. Hunter L* and a* values of eggshell were decreased (linear, P?<?0.05) as the concentrations of Mg in diets increased. In conclusion, feeding aged laying hens with diets containing increasing concentrations of Mg up to 3.0 g/kg improves eggshell strength, but has no detrimental effects on laying performance.     

Development of a UHPLC-FLD method for the analysis of ergot alkaloids and application to different types of cereals from Luxembourg

Ergot alkaloids are toxins produced by some species of fungi in the genus Claviceps, that may infect rye and triticale and, in a minor degree, other types of cereals. In this study, a new UHPLC-FLD method for the quantification of the six major ergot alkaloids as well as their corresponding epimers was developed. The sample preparation was done by a solid-liquid extraction with acetonitrile and clean-up via freeze-out. The method was fully validated and then applied to 39 samples (wheat, rye, triticale, and barley) harvested in Luxembourg in 2016. Samples were sieved (1.9?×?20 mm) prior to analysis in order to remove sclerotia, hosting the alkaloids. However, 23 samples still contained at least one ergot alkaloid >?LOQ and concentrations of the sum of the 6 ergot alkaloids ranged from 0.3 to 2530.1 μg/kg. Interestingly, the highest concentrations were measured in wheat and not in rye or triticale, suggesting that all kinds of cereals should be included in monitoring programs. The outcome of this study allowed giving a first overview of ergot alkaloid concentrations in cereals harvested in Luxembourg, and the measured concentrations were in similar ranges than in other parts of the world (e.g., Canada, France, Germany).     

Comparative studies on the effect of ergot contaminated feed on performance and health of piglets and chickens

Two dose response trials were conducted with piglets and chickens to study the effects of increasing amounts of ergot (Claviceps purpurea) with a defined alkaloid content and pattern on performance, biochemical serum characteristics and organ weights (of chickens). The ergot was mixed into the cereal-soybean meal based diets at levels of 0, 0.5, 1, 2 and 4?g/kg. The total alkaloid content of the ergot was analysed to be 2775?mg/kg and showed the following composition: ergometrine 8.1%, ergotamine 5.4%, ergocornine 3.2%, α-ergocryptine 1.9%, ergocristine 14.9% and residue 66.5%. Each treatment was tested with eight castrated male and eight female piglets over a period of 35 days (8?kg initial live weight) and 28 male chickens for 21 days (43?g initial live weight). Cumulative daily dry matter intake and live weight gain [g/d] were 595, 535, 560, 577 and 490 and 413, 399, 420, 443 and 347 for the piglets fed the unsupplemented control diet and the diets containing 0.5, 1, 2 and 4?g ergot per kg, respectively. Feed intake and live weight gain of the piglets fed the highest ergot supplemented diet were significantly decreased. Serum aspartate aminotransferase activity of the 4?g ergot treatment was significantly increased. Also serum albumin concentrations showed significant linear alterations. Serum activities of glutamate dehydrogenase, γ-glutamyltransferase, total protein and porcine growth hormone were not significantly influenced by dietary treatment. The experiment with chickens demonstrated no significant effects on performance due to dietary ergot exposure. The serum activities of glutamate dehydrogenase and alanine aminotransferase were not significantly influenced by dietary treatment while serum activities of γ-glutamyltransferase and aspartate aminotransferase and the concentrations of albumin and total bilirubin were significantly affected. Heart weights showed a significant linear decrease due to ergot feeding. According to these results, piglets seemed to react more sensitively on the occurrence of ergot in the diet as compared to chickens. The critical level of total ergot alkaloids for piglets seemed to be in the range from 5.6?mg to 11.1?mg/kg diet for the present study. Ergot effects on signs of inflammation in the proximal duodenum occurred in chickens fed diets containing 2.8?mg and 11.1?mg total ergot alkaloids/kg although live performance remained unaffected. Further studies are necessary to define the critical level of ergot alkaloids in dependence on alkaloid pattern.     

Investigations on the effects of rape oil quality,choline and methionine concentration in diets for laying hens on the trimethylamine content of the eggs,on trimethylamine metabolism and on laying performance

Abstract

An experiment was conducted to study the effects of graded levels of choline addition (0, 500, 1000 and 4000 mg/kg diet) in laying hen diets prepared either with degummed or refined rape oil on the performance, sensory properties and trimethylamine (TMA) contents of the eggs. Furthermore, the diets containing no supplemented choline or 4000 mg choline/kg diet were tested with adequate or inadequate methionine supply (4.2 vs. 2.8 g methionine/kg diet). TMA metabolism and N-balance were measured for the latter diet types, but only with the diets containing refined rape oil. Therefore, a total of 12 and 4 diets were tested in the feeding (n = 60) and balance study (n = 9). Laying performance (23 – 75 weeks of age) was not significantly influenced by increasing choline additions with the exception of feed-to-egg mass ratio which decreased significantly linearly (p _linear = 0.003). However, a significant interaction between choline addition and laying month was detected which was caused by a depression of performance of the unsupplemented control group occurring from the sixth laying month. The most obvious effect of an inadequate methionine supply was a temporary drop in performance between the third and sixth laying months. The mean TMA-concentration in pooled egg yolks [μg/g] increased with dietary choline concentration [mg/kg] in an exponentially related fashion (y = 1.14 + 4E^?10 ? x^2.71, r² = 0.962) and suggested only a minor influence of total dietary choline on TMA content up to approximately 2000 mg choline/kg. Individual TMA-concentrations varied greatly from 0.4 – 1.5 μg/g, from 2.2 – 34 μg/g and from 18.4 – 75 μg/g for eggs with a normal, aberrant and heavily aberrant odour, respectively. It is concluded that a total choline concentration of at least approximately 1500 mg/kg is necessary to maintain a maximal laying performance. An inadequate methionine supply cannot be compensated by an increased addition of choline. Neither degummed nor refined rape oil influenced the TMA content of eggs.     

Dietary ergot alkaloids as a possible cause of tail necrosis in rabbits

This study describes the association between tail necrosis in rabbits and mycotoxins in rabbit feed. Clinical cases of tail necrosis were observed in 14 out of 103 rabbits kept in an outdoor group housing, fed with hay and a commercial pelleted feed. The observed clinical symptoms, alopecia, erosions, crusts and necrosis were restricted to the tail area and exclusively occurred in young rabbits aged 113?±?20 days. Dermatological examination suggested that ischemia had caused necrosis. Analysis of blood samples showed an elevated level of creatine kinase. No weight loss occurred in affected rabbits. Trauma caused by injuries or technopathic lesions was also excluded. Histopathologically, the lesions were characterized by acute muscle fibre degeneration and chronic active dermatitis with granulation tissue formation. Necropsy of one rabbit revealed hepatocellular degeneration and necrosis as remarkable findings. Feed analysis for ergot alkaloids by enzyme immunoassays yielded a mean and maximum ergot alkaloid content of 410?±?250 μg/kg and 1,700 μg/kg, respectively. Faeces of affected rabbits contained ergot alkaloids at levels up to 200 μg/kg. The mean and maximum dietary intake of total ergot alkaloids were 17 and 71 μg/kg bodyweight, respectively. Fusarium toxins (trichothecenes, zearalenone, fumonisins) were also found in the feed, but at levels which did not explain the observed effects. The results indicate that ergot alkaloids may have been the cause of tail necrosis, which is supported by literature data showing that rabbits are especially sensitive towards these toxins.     

An Optimal Dietary Zinc Level of Brown-Egg Laying Hens Fed a Corn–Soybean Meal Diet

An experiment was conducted to estimate the optimal dietary zinc (Zn) level of brown-egg laying hens fed a corn–soybean meal diet from 20 to 40 weeks of age. A total of 120 20-week-old Beijing Red commercial laying hens were randomly allotted by bodyweight to one of five treatments with six replicates of four birds each in a completely randomized design, and fed a Zn-unsupplemented corn–soybean meal basal diet containing 27.95 mg Zn/kg by analysis and the basal diets supplemented with 30, 60, 90, or 120 mg Zn/kg as Zn sulfate (reagent grade ZnSO₄·7H₂O) for a duration of 20 weeks. Laying performance, egg quality, tissue Zn concentrations, and activities of serum alkaline phosphatase (AKP), and liver copper-Zn superoxide dismutase (CuZnSOD) were measured. Regression analyses were performed to estimate an optimal dietary Zn level whenever a significant quadratic response (P < 0.05) was observed. Tibia Zn concentration (P = 0.002) and serum AKP activity (P = 0.010) showed significant quadratic responses to dietary supplemental Zn levels. The estimates of dietary Zn requirements for brown-egg laying hens from 20 to 40 weeks of age were 71.95 and 64.63 mg/kg for tibia Zn concentration and serum AKP activity, respectively. The results from this study indicate that the tibia Zn might be a more suitable and reliable parameter for Zn requirement estimation, and the optimal dietary Zn level would be about 72 mg/kg for brown-egg laying hens fed a corn–soybean meal diet from 20 to 40 weeks of age.     

Comparative studies on the effect of ergot contaminated feed on performance and health of piglets and chickens

Two dose response trials were conducted with piglets and chickens to study the effects of increasing amounts of ergot (Claviceps purpurea) with a defined alkaloid content and pattern on performance, biochemical serum characteristics and organ weights (of chickens). The ergot was mixed into the cereal-soybean meal based diets at levels of 0, 0.5, 1, 2 and 4 g/kg. The total alkaloid content of the ergot was analysed to be 2775 mg/kg and showed the following composition: ergometrine 8.1%, ergotamine 5.4%, ergocomine 3.2%, alpha-ergocryptine 1.9%, ergocristine 14.9% and residue 66.5%. Each treatment was tested with eight castrated male and eight female piglets over a period of 35 days (8 kg initial live weight) and 28 male chickens for 21 days (43 g initial live weight). Cumulative daily dry matter intake and live weight gain [g/d] were 595, 535, 560, 577 and 490 and 413, 399, 420, 443 and 347 for the piglets fed the unsupplemented control diet and the diets containing 0.5, 1, 2 and 4 g ergot per kg, respectively. Feed intake and live weight gain of the piglets fed the highest ergot supplemented diet were significantly decreased. Serum aspartate aminotransferase activity of the 4 g ergot treatment was significantly increased. Also serum albumin concentrations showed significant linear alterations. Serum activities of glutamate dehydrogenase, gamma-glutamyltransferase, total protein and porcine growth hormone were not significantly influenced by dietary treatment. The experiment with chickens demonstrated no significant effects on performance due to dietary ergot exposure. The serum activities of glutamate dehydrogenase and alanine aminotransferase were not significantly influenced by dietary treatment while serum activities of gamma-glutamyltransferase and aspartate aminotransferase and the concentrations of albumin and total bilirubin were significantly affected. Heart weights showed a significant linear decrease due to ergot feeding. According to these results, piglets seemed to react more sensitively on the occurrence of ergot in the diet as compared to chickens. The critical level of total ergot alkaloids for piglets seemed to be in the range from 5.6 mg to 11.1 mg/kg diet for the present study. Ergot effects on signs of inflammation in the proximal duodenum occurred in chickens fed diets containing 2.8 mg and 11.1 mg total ergot alkaloids/kg although live performance remained unaffected. Further studies are necessary to define the critical level of ergot alkaloids in dependence on alkaloid pattern.     

Effects of different levels of ergot in concentrates on the growing and slaughtering performance of bulls and on carry-over into edible tissue

Abstract

The aim of the present study was to examine long-term effects of low levels of ergot alkaloids on growing bulls. Natural grown ergot with a mean total alkaloid concentrations of 633 mg/kg, and ergotamine (25%), ergocristine (15%) and ergosine (13%) as the most prominent alkaloids, was used. In a dose-response study 38 Holstein Friesian bulls were fed with three different doses of this ergot (0, 0.45 and 2.25 g/kg concentrate corresponding to an average total alkaloid concentration of the daily ration of 0, 69 and 421 µg/kg DM) over a period of approximately 230 days. Live weight, feed intake and health condition were monitored over the entire test period. The bulls were slaughtered at a live weight of approximately 550 kg. Carcass composition and quality were recorded and samples of liver, muscle, kidneys, fat, bile, urine and blood were analysed for ergot alkaloids. Liver enzyme activities and total bilirubin were measured in the blood. Statistically, no significant differences were detectable between the three feeding groups. Mean live weight gain over all groups was 1.41 kg/d with a mean dry matter intake of 7.35 kg/d. No carry over into tissues could be proved out of the experiment. To derive a no-effect level for beef cattle further research including higher ergot doses will be necessary.     

The influence of ergot-contaminated feed on growth and slaughtering performance,nutrient digestibility and carry over of ergot alkaloids in growing-finishing pigs

Abstract

Diets containing 0, 1 and 10 g ergot (Claviceps purpurea) per kg, corresponding to mean total alkaloid contents of 0.05, 0.60 and 4.66 mg/kg (sums of ergometrine, ergotamine, ergocornine, α-ergocryptine, ergocristine, ergosine and their -inine isomers analysed by a HPLC-method), were each fed ad libitum to 12 pigs in the BW range of 30–115 kg to study the effect of ergot-contaminated feed on growth and slaughtering performance and the carry over of ergot alkaloids. Additionally, balance trials were conducted to investigate the digestibility of nutrients. Tendencies towards reduced feed intake and BWG were observed at a feeding level of 4.66 mg total alkaloids per kg diet. Typical symptoms of ergot poisoning were not observed. Heart and spleen weights showed significant linear increases. Differences in carcass quality due to dietary treatment were not detected. No genuine ergot alkaloids were found in physiological samples. The balance trials demonstrated a significantly decreased protein digestibility for the most highly supplemented diet.     

The influence of ergot-contaminated feed on growth and slaughtering performance, nutrient digestibility and carry over of ergot alkaloids in growing-finishing pigs

Diets containing 0, 1 and 10 g ergot (Claviceps purpurea) per kg, corresponding to mean total alkaloid contents of 0.05, 0.60 and 4.66 mg/kg (sums of ergometrine, ergotamine, ergocornine, alpha-ergocryptine, ergocristine, ergosine and their -inine isomers analysed by a HPLC-method), were each fed ad libitum to 12 pigs in the BW range of 30-115 kg to study the effect of ergot-contaminated feed on growth and slaughtering performance and the carry over of ergot alkaloids. Additionally, balance trials were conducted to investigate the digestibility of nutrients. Tendencies towards reduced feed intake and BWG were observed at a feeding level of 4.66 mg total alkaloids per kg diet. Typical symptoms of ergot poisoning were not observed. Heart and spleen weights showed significant linear increases. Differences in carcass quality due to dietary treatment were not detected. No genuine ergot alkaloids were found in physiological samples. The balance trials demonstrated a significantly decreased protein digestibility for the most highly supplemented diet.     

Amino acid digestibility of different rye genotypes in caecectomised laying hens

This study investigated the variability of amino acid (AA) digestibility of rye grains in laying hens. Relationships between AA digestibility and physical properties (thousand seed weight, test weight, falling number, and extract viscoelasticity), chemical composition (proximate nutrients, non-starch polysaccharides, AA, minerals, and inositol phosphates), gross energy concentration, and in vitro solubility of nitrogen (N) of the grains were also examined. Twenty rye genotypes were grown under standardised agronomic and environmental conditions as part of a collaborative research project known as “GrainUp”. Each genotype was added to a basal diet at 500 g/kg at the expense of maize starch to produce 20 rye diets. The experimental design comprised four Latin Squares (6 × 6) distributed over two runs, resulting in 12 experimental periods. Caecectomised laying hens (LSL-Classic) were individually kept in metabolism cages. Excreta were collected quantitatively for 4 d, and AA digestibility of the rye genotypes was determined using a regression approach. The digestibility of AA was generally low but varied significantly among the 20 rye genotypes, especially for Lys (digestibility range 35–59%), Met (57–75%), Thr (34–54%), and Trp (36–71%). Nevertheless, physical and chemical characteristics as well as the in vitro solubility of N correlated in only a few cases with AA digestibility. Multiple linear regression was used to calculate equations to predict AA digestibility based on the analysed characteristics. However, their explanatory power, as judged by the adjusted R², was not sufficiently precise for practical application (below 0.6 for most AA). In conclusion, the AA digestibility of rye grain is generally low and varies significantly between crop genotypes. Equations based on its physical and chemical characteristics are not sufficiently precise to be useful for feed formulation.     

Distribution of ergot alkaloids and ricinoleic acid in different milling fractions

The sclerotia of the fungus Claviceps sp. are still a challenge for the milling industry. Ergot sclerotia are a constant contamination of the rye crop and have to be removed by modern milling technologies. Changing sizes and coloration of the sclerotia make it difficult to separate them from the grain. Ergot sclerotia are a problem when cleaning is insufficient and non-separated specimens or sclerotia fragments get into the milling stream and thus ergot alkaloids are distributed into the different cereal fractions. In model milling experiments, the residues of ergot in rye flour and the distribution of ergot into different milling fractions were investigated. Rye grains were mixed with whole ergot sclerotia and in another experiment with ergot powder and cleaned afterwards before milling. The ergot alkaloids ergometrine, ergosine, ergotamine, ergocornine, ergocryptine, ergocristineand their related isomeric forms (-inine-forms), and additionally ricinoleic acid as a characteristic component of ergot, were quantified in the different milling fractions. From the first experiment, it can be shown that after harvesting even simple contact of sclerotia with bulk grains during ordinary handling or movement of bulk grain in the granary is sufficient to contaminate all the healthy or sound rye grains with ergot alkaloids. Thereby, the amount of ergot residue correlates with the amount of peripheral layers of rye grains in the flour. In an additional experiment without sclerotia specimens, bulk rye grains were loaded with powder of sclerotia. After subsequent cleaning, aconcentration of ergot alkaloids was detected, which was tenfold higher than the ergot alkaloidconcentration of the experiment with intact ergot sclerotia.     

Adult:Child Differences in the Intraspecies Uncertainty Factor: A Case Study Using Lead

Adults and children differ in their susceptibility to the toxic effects of lead. Lead was therefore used as a case study to evaluate intraspecies differences by comparing the adult and child minimal Lowest Observed Adverse Effect Level (LOAEL) or the No Observed Adverse Effect Level (NOAEL), allowing an evaluation of the ten-fold intraspecies uncertainty factor (UF). The lead intakes (in µg/kg/d) necessary to achieve target blood lead (PbB) levels reflecting the minimal LOAEL or NOAEL were determined using biokinetic slope factors (BKSFs), which relate lead uptake to PbB levels. The analyses assumed chronic, low-level oral exposure to lead, and the response of a typical adult and child. Child analyses used a target geometric mean (GM) PbB of 4.6?µg/dL (95% of population <10?µg/dL), resulting in lead intakes of 1.9?µg/kg/day (assuming 100% soluble lead) and 4.9?µg/kg/day (assuming 25% soluble lead and 75 % soil lead). Adult analyses assumed intake of 100 % soluble lead, and used target GM PbB levels of 4.2?µg/dL (95% of population <11.1 µg/dL) and 11.4?µg/dL (95% of population <30?µg/dL), resulting in lead intakes of 1.9?µg/kg/day and 5.1?µg/kg/day, respectively. The results indicate that despite the greater vulnerability of young children to the effects of lead as compared to adults, the minimal LOAEL or NOAEL for lead is remarkably similar between children and adults. In this case, the application of a tenfold intraspecies uncertainty factor to adjust the adult minimal LOAEL or NOAEL for a child would be unnecessary, despite the well-established vulnerability of children to lead.     

Dietary thyroxine induces molt in chickens (Gallus gallus domesticus)

Thyroxine increases during a molt in wild and captive birds, and thyroidectomy prevents induction of molt. This trial examined the effect of dietary thyroxine on molt induction molt in chickens (laying hens, 59 weeks of age). In a completely randomized design (n=15 hens/replication; 6 replications/treatment), hens were randomly assigned to either a traditional molting program consisting of feed withdrawal (FWD), or to diets containing 40 mg thyroxine/kg diet (HT), 20 mg thyroxine/kg diet (LT), or 40 mg thyroxine from thyroactive iodinated casein/kg diet (TIC). The molting treatment lasted 7-13 d, until egg production reached 0%. After molt induction, birds had ad libitum access to the same diet, until egg production was re-initiated and maximized ( approximately 56 d). All treatments induced molt, based upon cessation of egg laying and regression of ovary and oviduct. Birds on FWD treatment lost more body weight during the molting period, but gained more after molt compared to thyroxine treatments (P<0.01 for each), although all body weights were similar when egg production was maximized. Data demonstrate that oral thyroxine, in purified or non-purified form, induces a molt and may enhance animal well-being by reducing the need for FWD.     

Zum Einfluss einer hydrothermischen Behandlung auf den Ergotalkaloidgehalt von mutterkornbelastetem Roggen

Hydrothermal treatments are primarily used to increase the digestibility of nutrients and therefore to improve the feeding value of feedstuffs mainly for non-ruminants. Other positive side effects may occur, e.g. a decrease in toxicity of feed contaminated with mycotoxins. To study such effects, 4 batches of rye containing different percentages (0.8, 4.2, 8.3 and 25%) of ergot (Claviceps purpurea) were expanded and ergot alkaloid contents were analysed. After pre-conditioning of each batch by steam exposure for approx. 2 min, at 95 °C and 17% moisture, the material was expanded for approx. 5 sec. at 120 °C, 18% moisture, 40 bar mechanical pressure and 20 kWh/t mechanical energy input. Samples were collected before and after pre-conditioning and after expanding. Ergot alkaloids were analysed by HPLC. Analysis includedErgometrine, Ergotamine, Ergocornine, Ergocryptine, Ergocristine, Ergosine and their respective-inine isomers, the sum of these 12 ergot alkaloids was referred to as the total alkaloid content. On average, the hydrothermal treatment (pre-conditioning and expanding) caused a decrease of the total ergot alkaloid content of approx. 10%. Except for the batch containing 0.8% ergot, the efficiency of the hydrothermal treatment decreased with increasing ergot concentration in the batches. In general, the hydrothermal treatment changed the proportions of the ergot alkaloid isomers since the percentages of the-inine isomers of the total ergot alkaloid contents were increased with reduced-ine percentages. Whether this alteration is of toxicological relevance should be evaluated in animal experiments.     

Effects of different levels of ergot in concentrate on the health and performance of male calves

A number of studies dealing with the effects of ergot and ergot alkaloids on the health and performance of poultry and pigs were reported in the past, but only a few studies and field reports are available for ruminants. Therefore, a dose-response study was carried out with calves since young animals are considered to be especially sensitive to ergot. A total of 35 male Holstein calves were randomly assigned to three feeding groups after one month of feeding milk replacer. The mean initial live weight of the calves was 49.4±5.7 kg. One control group was fed an ergot-free concentrate (n=12), one group an ergot proportion of 1000 mg/kg in the concentrate (n=ll), and another group was fed a concentrate containing 5000 mg/kg ergot (n=12). Hay, grass silage and water were available forad libitum consumption, whereas the daily concentrate portion was restricted to 2 kg. Live weight, health parameters and feed intake were monitored over the experimental period of 84 days. In addition, blood samples were taken from theVena jugularis at the beginning and at the end of the experiment and analysed for ergot alkaloids and liver parameters. Total dry matter intake, live weight gain and feed-to-gain ratio were not significantly influenced by increasing ergot proportions when the whole experimental period was considered, although there was a trend for an ergot-related decrease in concentrate intake during the first 6 weeks of the experiment. After this period of time, it seemed that calves got used to the presence of ergot in the concentrate and were able to adjust their intake to the level of the control group. Moreover, health and liver parameters, such as total bilirubin, aspartate aminotransferase, glutamate dehydrogenase, gamma-glutamyl transpeptidase and creatine kinase in the serum were not significantly influenced by dietary treatments. Concentrations of the individual ergot alkaloids in serum were lower than the detection limits of the applied HPLC-method. In conclusion, it can be assumed that an ergot contamination of the concentrate up to 5000 mg/kg resulted in a transient depression of concentrate intake by the calves. However, no significant effects on health and performance could be detected when the entire test period of 84 days was considered. Presented at the 28^th Mykotoxin-Workshop, Bydgoszcz, Poland, May 29–31, 2006     

Determination of ergot alkaloids in feed by HPLC

A HPLC method for the determination of ergometrine, ergotamine, ergocristine, α-ergocryptine and ergocornine in cereals for animal feed and in mixed feed with high cereal content was developed. Samples were extracted under acidic conditions using a mixture of phosphoric acid and acetonitrile, the extract purified with solid phase extraction cartridges (strong cation exchange), and ergot alkaloids detected after gradient elution on a C18 column by HPLC with fluorescence detection. Detection and determination limits for each individual alkaloid were at 5 (μ/kg and 10 (μg/kg, respectively. With this method, high recovery (82–120%) and good reproducibility was achieved for wheat, rye and mixed feeds, at a sum of total determined alkaloids of < 500 (μg/kg. This method was used to analyse Bavarian feeds (n=124) over three years (2005–2007), and ergot alkaloids were detected in 91 % of the samples. The majority of positive samples had ergot alkaloid contents of < 250 μg/kg, the median alkaloid level was at 70 (μg/kg. The maximum sum of total determined alkaloids exceeded 1000 (μg/kg in wheat, triticale, rye, and mixed feeds, the highest result was obtained for mixed feed (4880 (μg/kg). Parts presented at the Feed Safety Conference, Namur, Belgium, Nov 27–28, 2007     

Effects of dietary chromium and zinc on egg production, egg quality, and some blood metabolites of laying hens reared under low ambient temperature

This experiment was conducted to evaluate the effects of chromium (chromium picolinate, CrPic) and zinc (ZnSO₄·H₂O) on egg production, egg quality, and serum insulin, corticosterone, glucose, cholesterol, and total protein concentrations of laying hens reared under a low ambient temperature (6.8°C). One hundred twenty laying hens (Hy-Line; 32 wk old) were divided into 4 groups, 30 hens per group. The laying hens were fed the control diet (T1) or the control diet supplemented with either 400 μg of Cr/kg of diet (T2), 30 mg of Zn/kg of diet (T3), or 400 μg of Cr plus 30 mg of Zn/kg of diet (T4). Although the dry matter intake (DMI) was similar (p>0.05) for all treatment groups, supplemental chromium and zinc either individually or together increased live-weight change, egg production, and improved feed efficiency (p<0.05). However, no significant differences were observed between T4 and T2 or T3. Compared to T1, supplemental chromium and zinc increased egg weight, eggshell weight, eggshell thickness, egg specific gravity, and Haugh unit (p<0.05) in T2, T3, and T4 groups, among which there was no significant difference. Serum insulin concentration increased (p<0.05) and corticosterone concentration decreased (p<0.05) with dietary chromium and zinc supplementation. Serum glucose and cholesterol concentrations decreased (p<0.05) and protein concentrations increased (p<0.001) with dietary chromium and zinc supplementation in all treatment groups. The results of this study indicated that either supplemental dietary chromium or zinc increased plasma insulin and decreased corticosterone concentrations and that had a positive effect on performance of laying hens under low ambient temperature.     

Dynamic feeding low and high methionine diets affect the diurnal rhythm of amino acid transporters and clock related genes in jejunum of laying hens

This study was conducted to investigate effects of dynamic feeding low and high methionine (Met) diets on circadian clock gene expression in jejunum of laying hens. A total of 180 laying hens (Brown Hy-line, 41 weeks old) were allocated into 3 groups with 6 replicates each. The CON group received diet containing 0.30% Met, LH group received low Met diet (0.27% Met) at 07:30 h and high Met diet (0.33% Met) at 15:30 h, while HL group received high Met diet at 07:30 h and low Met diet at 15:30 h. After 10 weeks, jejunum samples were collected at 4 h intervals in a daily cycle initial starting at 07:30 h before feeding. Results showed that dynamic feeding of Met significantly affected the wave of mRNA expression of B0AT1, LAT1, SNAT2, CAT-2, and y⁺LAT2 by feeding regime during a day (P<0.05). Dynamic feeding of Met also influenced the fluctuation of relative mRNA expression of Clock, Bmal1, Cry1, Cry2, Per2, and Per3 significantly in hens during a day (P<0.05). These results demonstrated that dynamic feeding different Met level diets of hens affected the rhythmic fluctuation of amino acid transporters and may affected intestinal function by influencing the clock-related genes further.     

Effects of Zinc Oxide Nanoparticles on Performance,Egg Quality,Tissue Zinc Content,Bone Parameters,and Antioxidative Status in Laying Hens

The objective of this study was to observe the effects of dietary supplementation with zinc oxide nanoparticles (ZnO-NPs) on performance, egg quality, tissue Zn content, bone parameters, superoxide dismutase activity (SOD), and egg malondialdehyde (MDA) content in laying hens. A total of 288 laying hens at 64 weeks of age were randomly assigned to 4 treatments, 6 replicates, with 12 birds each. Experimental diets included the based diet (without Zn supplementation), and basal diet supplemented with 40, 80, and 120 mg Zn/kg from ZnO-NPs. Feed intake and egg mass were significantly higher in the 40 and 80 ZnO-NPs groups than the other groups. The birds in the 80 ZnO-NPs group had significantly higher egg product than the 120 ZnO-NPs and control groups. Egg shell thickness and shell strength significantly increased in the 40 and 80 ZnO-NPs groups. Moreover, Haugh unit significantly improved in the groups supplemented with ZnO-NPs, compared to the control group. Bone-breaking strength was significantly greater in the 80 ZnO-NPs group than the 120 ZnO-NPs and control groups. Also, ash weight was significantly greater in the 40 and 80 ZnO-NPs groups than the control group. There were significant differences among the groups in the Zn content in plasma, tibia, liver, pancreas, and egg. Relative to the control group, ZnO-NPs supplementation significantly increased the activities of SOD in the liver, pancreas, and plasma. The MDA content in egg was significantly reduced in the groups supplemented with ZnO-NPs. In conclusion, this study demonstrates that ZnO-NPs as dietary supplementation can improve the performance of laying hens, and levels of 40 to 80 ZnO-NPs are the optimal concentrations.