Untersuchungen über den Eiweißbedarf der Mastente unter Berücksichtigung einer Lysin-, Methionin- und Vitamin-B-Ergänzung des Mastfutters: (Kurze Originalmitteilung)

In the presented study the effect of different iodine (I) levels and sources in hen feed on the iodine concentration of different tissues, blood serum, and eggs of laying hens was studied. For this purpose, two experiments were conducted with 30 laying hens each. In these experiments feed was enriched with KI and Ca(IO₃)₂, respectively, at 0 (Control), 0.25, 0.5, 2.5 and 5 mg I/kg feed, resulting a analysed iodine level from 0.44 to 4.20 mg/kg feed. After four weeks experimental feeding the iodine concentrations of thyroid glands, blood, meat, liver, abdominal fat and eggs were measured with inductively coupled plasma mass spectrometry. The experimental treatment did not affect hen performance. The iodine supplementation significantly increased the iodine concentration of eggs (144–1304 μg/kg), thyroid glands (3367–5975 μg/g), blood serum (16–67 μg/kg) and liver (13–43 μg/kg). Meat (about 14 μg I/kg) and abdominal fat (about 12 μg I/kg) were not significantly affected by iodine treatment. Comparative regression analyses showed that at a similar iodine intake, the supply via KI resulted in significantly higher iodine deposition into eggs than Ca(IO₃)₂. Due to the high carry-over of iodine into eggs, eggs may considerably contribute to the iodine supply of the consumers.     

Effects of Chromium Propionate on Egg Production,Egg Quality,Plasma Biochemical Parameters,and Egg Chromium Deposition in Late-Phase Laying Hens

This study was conducted to investigate the effects of chromium propionate on egg production, egg quality, plasma biochemical parameters and egg chromium deposition in late-phase laying hens. Four hundred thirty-two 60-weeks old laying hens were divided into four groups of 108 birds per group according to egg production. The dietary treatments consisted of the basal diet adding with 0, 200, 400, and 600 μg/kg chromium as chromium propionate. All laying hens were given feed and water ad libitum for 8 weeks. The addition of 400 μg/kg Cr as chromium propionate increased egg production (P?<?0.01) during the later 4 weeks, but decreased albumen height, yolk color score, and Haugh unit of eggs. Six hundred micrograms per kilogram Cr as chromium propionate supplementation improved shell thickness (P?<?0.05). 200 μg/kg Cr as chromium propionate supplementation decreased the uric acid concentration by 31 % (P?<?0.05). However, supplemental Cr did not affect the egg chromium deposition of hens (P?>?0.05). These data indicated that feeding of late-phase laying hens with chromium propionate could improve egg production, increase eggshell thickness, but do not result in abnormal levels of chromium deposition in eggs.     

Effects of providing dietary wood (oak) charcoal to broiler chicks and laying hens

Three experiments were carried out to determine whether dietary wood (oak) charcoal applied during entire or phase feeding period would affect growth performance, abdominal fat weight, carcass weight, carcass yield, carcass composition and nutrient excretion of broilers and to determine whether dietary wood charcoal supplementation would affect laying performance and egg quality of laying hens. In the first experiment, different inclusion levels (0, 25, 50 and 100 g/kg feed) of wood charcoal in the diet were examined for a 6-week-period using broiler chicks of initial age 1 week. Dietary wood charcoal significantly increased feed intake (P<0.001), body weight gain (P<0.001) and improved feed conversion ratio (P<0.05) up to 28 days of age. However, at 49 days of age, charcoal inclusion did not significantly (P>0.05) affect body weight gain, feed intake, carcass weight and carcass yield, but increased (P<0.05) feed conversion ratio, carcass ash content, fat excretion, while reducing (P<0.05) mineral excretion in a dose dependent manner. In the second experiment, a phase application of dietary wood charcoal for a 6-week-period broiler chicks of initial age 1 week was assessed. During the first 28 days of age wood charcoal improved feed conversion ratio significantly (P<0.05). At 49 days of age, the groups receiving charcoal in the starter and/or finisher diets showed significantly (P<0.05) higher body weight gain and carcass weight than the control group receiving no charcoal. In the third experiment, different levels (0, 10, 20 and 40 g/kg feed) of wood charcoal supplementation to a layer diet were examined for a 7-week-period using laying hens of initial age 34 weeks. Dietary charcoal supplementation did not have a significant effect on any parameters related to performance and egg quality, but significantly reduced number of cracked eggs and the reduction was dose dependent (P<0.01). These data demonstrate that wood charcoal inclusion to the diet could be of value in improving broiler performance during the first 28 days of fattening period. In later ages, the positive effects of wood charcoal are limited. However, in laying hens dietary supplementation of wood charcoal reduces number of cracked eggs.     

Effects of Dietary Form of Selenium on Its Distribution in Eggs

The objective of this experiment was to investigate the selenium distribution in eggs from hens fed diets supplemented with Se from sodium selenite (SS) or selenium-enriched yeast (SY). One-day-old female chickens of Hy-Line Brown breed were randomly divided into four groups according to dietary treatments and, for the subsequent 9?months, were fed diets which differed only in the form or amount of Se supplemented. During the whole experiment, group 1 (control) was fed basal diet (BD) with only background Se level of 0.13?mg/kg dry matter (DM). Diets for groups 2 and 3 consisted of BD supplemented with an Se dose of 0.4?mg/kg DM either in the form of SS or SY, respectively. Group 4 was fed BD supplemented with 0.9?mg Se/kg DM from SY. After 9?months of dietary treatments, the Se levels in egg yolk and albumen from hens fed unsupplemented diet were almost identical whereas eggs from hens given diet supplemented with SS showed significantly higher Se deposition in yolk than in albumen (P?相似文献   

Effects of phytase supplementation on production performance,egg and bone quality,plasma biochemistry and mineral excretion of layers fed varying levels of phosphorus

Excessive fecal excretion of phosphorus (P) has increasingly become an environmental issue due to oversupply of P in layer rations, and thus it is imperative to minimize safety margins for P to ensure the sustainability of the egg industry. In this study, a 12-week feeding trial (22 to 34 weeks of age) was conducted to evaluate the effects of phytase supplementation on production performance, plasma biochemistry, egg and bone quality and P excretion of laying hens fed various levels of non-phytate P (NPP). Forty-eight Lohmann white laying hens were randomly allocated to one of six corn–soybean meal–oat-based diets: diets containing 2.0, 2.5 or 3.0 g/kg NPP without phytase, and diets containing 1.0, 1.5 or 2.0 g/kg NPP with phytase (1 000 U/kg diet) where phytase inclusion was expected to provide 1.0 g/kg NPP to laying hens, thus making the phytase-unsupplemented treatment served as a control for the phytase-supplemented treatment accordingly. Productive performance was recorded during the experimental period. Blood and egg samples were collected, and digestibility studies were conducted at weeks 6 and 12 of the experiment. Bone mineralization was evaluated at the end of the experiment. Egg weight and egg production, feed consumption, BW and feed conversion ratio of laying hens fed lower NPP diets supplemented with phytase were comparable to those of hens fed high NPP phytase-unsupplemented controls. Eggshell thickness, specific gravity, Haugh units, tibia bone mineral density, tibia ash percent, plasma P and other biochemical parameters were not significantly different among dietary treatments. Total P intake, excretion and retention were affected by diet (P < 0.001), but its deposition in eggs was not significantly different. Contrast analysis further showed that total P excretion of phytase present vs phytase absent was averagely reduced by 40.4 mg/hen per day (P < 0.01). Moreover, total P excretion was linearly (P < 0.01) reduced with lowering dietary NPP, and this relationship was similar regardless of whether phytase was supplemented or not. The results from this study indicated that NPP levels in laying hen diets could be reduced to 1.0 g/kg (excluding the portion of NPP released by phytase) with the inclusion of phytase, without negative effects on production performance and health of the hens, thereby diminishing P excretion into environment.     

Potential of alfalfa as an alternative molt induction diet for laying hens: egg quality and consumer acceptability

Dietary molt induction to initiate additional egg laying cycles in commercial laying hen flocks is a wide spread practice in the United States. Feed deprivation is the most commonly used method but this practice has generated several concerns which has lead to research for viable alternative approaches. From a management standpoint a single ingredient molting diet consisting of high fiber-low energy represents an easily adaptable diet for large laying hen production units. Alfalfa meal is readily available in most commercial locations and possesses many of the desirable properties of an ideal laying hen molt diet. In the current study hens at a commercial laying facility were molted by both alfalfa and feed deprivation. After the hens had reentered post-molt commercial egg production, eggs were examined for egg quality performance. Egg shell strength, albumen height, yolk height, weight, length, and yolk color were all tested using various mechanical techniques. The eggs were also sampled for testing by consumer sensory panels that assessed the desirability of the eggs' color and flavor/texture. Eggs laid by hens molted by alfalfa had a significantly lower (p<0.05) "a*" level of colorimetry. Eggs laid by hens molted with alfalfa also exhibited significantly higher (p<0.05) egg weights and length. In the consumer sensory test, there was no significant difference (p>0.05) in color or flavor/texture scores in eggs from either feed deprived or alfalfa molted hens. The consumer sensory and mechanical quality attributes indicates that alfalfa shows promise as an alternative molt induction diet by providing a single diet option for extending egg production into a second egg laying cycle.     

Determination of normal human intrathyroidal iodine in Caracas population

This study focuses on the determination of iodine content in healthy thyroid samples on male population from Caracas, Venezuela. Contribution to establish a baseline of iodine content in thyroid glands and hence to compare the iodine thyroid concentration of the Venezuelan population with other countries is also our objective. Male post-mortem individual samples were analyzed using a spectrophotometric flow injection method, based on the Sandell–Kolthoff reaction. The median intrathyroidal iodine concentration was 1443±677 μg/g (wet weight), ranging from 419 to 3430 μg/g, which corresponds to a median of total iodine content of 15±8 mg (ranging from 4 to 37). These results were higher than those values reported in the literature. No correlation of iodine content with age or weight of the healthy gland was found.     

Effect of long-term administration of arsenic (III) and bromine with and without selenium and iodine supplementation on the element level in the thyroid of rat

The aim of this study was to evaluate the influence of arsenic and bromine exposure with or without iodine and selenium supplementation on the element level in the thyroid of rats. Four major groups of Wistar female rats were fed with respective diets: group A - standard diet, group B - iodine rich diet (10 mg I/kg food), group C - selenium rich diet (1 mg Se/kg) and group D - iodine and selenium rich diet (as in group B and C). Each group was divided into four subgroups per 7 animals each receiving either NaAsO(2) ip (6.5 mg.kg(-1) twice a week for two weeks and 3.25 mg.kg(-1) for six weeks) or KBr in drinking water (58.8 mg.l(-1)) for 8 weeks or combined administration of both substances. Remaining subgroup served as controls. After 8 weeks thyroid glands were analyzed by ICP-MS for As, Br, Se, and I content. The exposition of rat to arsenic or bromine causes the accumulation of these elements in the thyroid gland ( approximately 18 ppm of As, approximately 90 ppm of Br) and significantly affects iodine and selenium concentration in the thyroid. In iodine and/or selenium supplemented rats the bromine intake into the thyroid was lowered to approximately 50% of the level in unsupplemented animals. Also selenium thyroid level elevated due to KBr administration was lowered by iodine supplementation in the diet. The accumulation of arsenic in the thyroid was not influenced by selenium or iodine supplementation; however, As(III) administration increased iodine thyroid level and suppressed selenium thyroid level in selenium or iodine supplemented group of animals.     

Performance,Egg Quality Traits,and Serum Metabolite Concentrations of Laying Hens Affected by Dietary Supplemental Chromium Picolinate and Vitamin C Under a Heat-Stress Condition

A 3?×?2 factorial experiment consisting three levels (0, 200, and 400 μg/kg) of chromium (chromium picolinate) and two levels (0 and 250 mg/kg) of vitamin C was employed to evaluate the effects of these dietary supplements on performance, egg quality traits, and serum biochemical parameters of heat-stressed laying hens (Lohmann LSL-Lite) from 66 to 74 weeks of age. Feed intake increased when birds were given either 400 μg/kg chromium or 250 mg/kg vitamin C (P?<?0.05), but the birds that received both chromium and vitamin C consumed feed similar to those that received only chromium. Dietary treatments had no effect on egg production, egg mass, egg volume, feed conversion ratio, and body mass (P?>?0.05). The birds that fed on diet with chromium or vitamin C produced eggs with higher shell mass and thickness compared to the control. Both eggshell mass and thickness decreased when vitamin C and chromium were supplemented simultaneously, and birds given the diet supplemented with 400 μg/kg chromium and 250 mg/kg vitamin C had eggshell mass and thickness similar to those of the control group. The serum concentration of chromium increased due to increasing level of dietary chromium (P?<?0.05). The birds that received diet with chromium and vitamin C had higher serum concentrations of chromium compared to those that received only chromium (P?<?0.05). Similarly, the hens that received chromium and vitamin C had higher serum concentrations of calcium and phosphorus compared to the hens fed with other treatments (P?<?0.05). The birds given with supplemental chromium exhibited lower serum glucose, total cholesterol, and triglycerides concentrations but higher serum albumin and total protein concentrations compared to the other groups (P?<?0.05).     

Assessment of lighting needs by W-36 laying hens via preference test

Light intensity, spectrum and pattern may affect laying hen behaviors and production performance. However, requirements of these lighting parameters from the hens’ standpoint are not fully understood. This study was conducted to investigate hens’ needs for light intensity and circadian rhythm using a light tunnel with five identical compartments each at a different fluorescent light intensity of <1, 5, 15, 30 or 100 lux. The hens were able to move freely among the respective compartments. A group of four W-36 laying hens (23 to 30 weeks of age) were tested each time, and six groups or replicates were conducted. Behaviors of the hens were continuously recorded, yielding data on daily time spent, daily feed intake, daily feeding time, and eggs laid under each light intensity and daily inter-compartment movement. The results show that the hens generally spent more time in lower light intensities. Specifically, the hens spent 6.4 h (45.4%) at 5 lux, 3.0 h (22.1%) at 15 lux, 3.1 h (22.2%) at 30 lux and 1.5 h (10.3%) at 100 lux under light condition; and an accumulation of 10.0 h in darkness (<1 lux) per day. The 10-h dark period was distributed intermittently throughout the day, averaging 25.0±0.4 min per hour. This hourly light-dark rhythm differs from the typical commercial practice of providing continuous dark period for certain part of the day (e.g. 8 h at night). Distributions of daily feed intake (87.3 g/hen) among the different light conditions mirrored the trend of time spent in the respective light intensity, that is, highest at 5 lux (28.4 g/hen, 32.5% daily total) and lowest at 100 lux (5.8 g/hen, 6.7%). Hen-day egg production rate was 96.0%. Most of the eggs were laid in <1 lux (61.9% of total) which was significantly higher than under other light intensities (P<0.05). Findings from this study offer insights into preference of fluorescent light intensity by the laying hens. Further studies to assess or verify welfare and performance responses of the hens to the preferred lighting conditions and rhythm over extended periods are recommended.     

Feeding value of crambe press cake and extracted meal as well as production responses of growing-finishing pigs and dairy cows fed these by-products

To analyse the feeding value of crambe press cake (CPC) and crambe extracted meal (CEM), and the incorporation limits in pig diets, a series of balance trials with a total of 12 male castrates was conducted. Additionally, in a feeding trial the effect of 5 % and 10 % CPC or CEM on growth performance and on pork quality was tested. The CP content of CPC and CEM was 207 and 331?g/kg DM, respectively, and the residual EE 144 and 26?g/kg DM, respectively. The erucic acid concentration amounted to 56 % of total fatty acids. Glucosinolate contents were found to be 50?mmol/kg CPC-DM and 70?mmol/kg CEM-DM. The digestibility of OM was 54 % for both by-products and the ME contents were 10.6 and 9.3 MJ/kg DM for CPC and CEM, respectively. In the feeding trial, 10 % CPC in the diet significantly decreased BWG from 782?g/d (controls) to 742?g/d. Due to glucosinolate intake, the weight of liver, thyroid glands and kidneys was significantly increased. The body fat showed an increased deposition of erucic acid in back fat and intramuscular fat, but changes in sensory properties of the meat were not detected. It is recommended that the incorporation rate of CPC and CEM in diets for growing-finishing pigs should not exceed 5 %.

The balance experiments, carried out with four wethers each, showed that the OM of CPC and CEM was better digested by ruminants, amounting to 71% or 67%, respectively. The energy content amounted to 7.4 and 6.0 MJ NEL/ kg DM, respectively.

In the feeding trials with lactating cows, 30 % CPC or CEM in the concentrate resulted in a decrease of concentrate intake of about 7%. Due to the high residual fat content of CPC, the milk fat content decreased and the erucic acid content increased. The high glucosinolate intake affected the iodine concentration in the milk. CPC and CEM feeding decreased the iodine content from 271?– 117?μg/kg and from 182?– 77?μg, respectively. It is recommended that crambe by-products should not exceed 15 % in concentrates or an intake of 1?kg/d for dairy cows.     

Furnished cages for laying hens: study of the effects of group size and litter provision on laying location, zootechnical performance and egg quality

The furnished cage is a new housing system for layers. A current trend in furnished cage design is to increase group size and replace the litter box with a mat provided with litter. An experiment was set up to determine the effects of group size and litter provision on laying performance and egg quality of beak-trimmed ISA Brown hens housed in large furnished cages with more than 12 hens. Six treatments, each of 18 furnished cages (768 cm(2)/hen including nest and litter area) were compared in a 3 × 2 experimental trial: three group sizes (S20 (20 hens per cage), S40 (40) and S60 (60)), with or without feed as litter distributed on the mat of the litter area. The provision of facilities per hen was equal in all treatments. Mortality, laying rate, mean egg weight, feed intake and feed conversion ratio were unaffected by group size over the 53-week laying period, and performance exceeded the ISA production standards. The overall percentage of eggs laid in the nest exceeded 95% except that it was slightly lower in group S20 (92.0% ± 6.4% v. S40: 96.0% ± 3.3% and S60: 96.2% ± 2.7%) leading to a higher proportion of dirty eggs (S20: 1.6% ± 2.2%, S40: 1.4% ± 1.5%, S60: 1.0% ± 1.0%). At 66 to 70 weeks, eggs laid outside the nest had a slightly higher count of mesophilic bacteria on the eggshell (5.0 log CFU/egg ± 0.4) than those laid in the nest (4.8 log CFU/egg ± 0.5) but no difference in contamination was observed between group sizes. Litter provision had no effect on mortality, egg weight or egg quality traits except for a higher proportion of broken eggs in cages with litter (5.3% ± 6.2% v. 4.6% ± 5.7%). Providing hens with feed for litter was associated with a higher laying rate (97.3% ± 3.2% v. 94.8% ± 4.4% at 23 weeks) and an apparent improvement in feed efficiency at the beginning of the laying period (feed conversion ratio based on feed consumption at the trough: 2.18 ± 0.06 with litter v. 2.28 ± 0.09 without litter at 25 weeks). The results of this study showed that a high level of productivity and good egg quality could be obtained in large furnished cages. Further research is needed to assess the impact on hens' welfare and performance of using more economically competitive substrates than feed for litter.     

Melamine in eggs,plasma and tissues of hens fed contaminated diets

A study was conducted to evaluate the excretion pattern of melamine from feed into eggs, plasma, kidney, liver and muscle of laying hens. In particular, 90 laying hens were randomly allocated to three dietary treatments and fed diets contaminated with melamine at a level of 2.5, 25 and 250 mg of melamine/kg of diet for T1, T2 and T3 groups, respectively. The diets were offered in six replicate boxes (five hens each) for 13 days. Eggs were collected from each group for melamine quantification on days 0, 1, 3, 6, 9 and 13. At the end of the experimental period, one hen per box was randomly selected and slaughtered to collect plasma, liver, kidney and muscle samples. During the experiment, feeding diets with increasing levels of melamine had no effect (P > 0.05) on weight gain, feed intake, egg production, egg weight and mortality of laying hens. The melamine in eggs increased from day 1 after melamine ingestion and reached a plateau between days 6 and 13 of melamine ingestion. At steady-state condition, the melamine egg concentrations increased (P < 0.01) with treatments, being 0.026, 0.352 and 4.631 mg/kg for T1, T2 and T3, respectively. Similarly, the carryover of melamine from feed to egg increased (P < 0.05) with the levels of melamine in the diets, varying from 0.50 to 0.70 and 0.84 for T1, T2 and T3, respectively. The melamine was detected in plasma of all tested groups, increasing (P < 0.01) with levels of melamine in the diets (0.030, 0.266 and 4.102 mg/l in T1, T2 and T3, respectively). Melamine was not detected in kidney, liver and muscle of hens fed T1. Except for kidney sampled in the T3, no melamine concentration higher than 2.5 mg/kg, representing the maximum allowable limit set by the US Food and Drug Administration and European Union for food and feeds, was measured. The melamine resulted higher in plasma and kidneys than in the liver and muscle both in T2 and T3. The results confirmed the presence of an excretion pattern of melamine from feed to eggs and tissues in laying hens.     

Utilisation of iodine from different sources in pigs

Balance experiments have demonstrated that growing pigs fed a ration consisting of wheat, barley, extracted soya meal, dicalciumphosphate, and iodine‐free feeding salt utilised 48.8% of the received iodine.

The tested supplementary iodine sources included potassium iodide (KI), ethylenediamine dihydroiodide (EDDI), iodine humate (HUI) prepared from iodine acid (HIO₃), and the product P containing 0.004% iodine in an oil base (P). The amount of the supplemented iodine was in all cases 1 mg per 1 kg feed.

The utilisation of iodine from the supplements reached 93.6, 92.6, 90.7, and 67.9% for KI, EDDI, P, and HUI, respectively. The values were significantly higher compared with controls (P < 0.01). Compared with KI and EDDI, the utilisation of iodine from HUI was significantly lower (P < 0.01). The lower availability of iodine from HUI was probably due to the high binding capacity of humate.

The amount of urinary iodine excreted by control pigs receiving in the non‐supplemented ration 147.5 μg iodine per day, was 40.3 μg per day (27.3%). In the pigs receiving in the supplemented ration 1647.5 μg iodine per day, the amount of urinary iodine reached 734.9 to 805.0 μg per day (44.6 to 48.9%). The corresponding values of faecal excretion were 75.6 μg iodine per day (51.2%) for the control pigs and 106.2 to 121.1 μg iodine per day (6.45 to 7.35%) for the pigs fed the supplemented rations. A high amount of 528.6 μg iodine per day (32.1%) was excreted in the faeces by pigs of the group HUI.     

Untersuchungen über den Vitamin B2-Bedarf der Legehenne

Because of the well established function of carnitine possible effects of carnitine were studied in poultry. In trial I it was investigated if carnitine and its precursors (lysine, methionine) reduce the formation of abdominal fat in broilers. Chickens (10 groups of 10 chickens each) were fed different diets (control, lysine and methionine in excess and deficient, respectively, with or without 5% fat supplement, L‐carnitine and DL‐carnitine supplement, respectively).Performance (body weight gain, feed conversion), amount of abdominal fat and carnitine concentration in blood, muscles (M. sartorius, M.pectoralis superficialis, cardiac), liver and kidney were determined. Performance and abdominal fat were influenced by dietary fat, lysine and methionine as expected and were not altered by carnitine. Excess and deficiency of lysine and methionine did not influence, fat supplement reduced and carnitine supplementation significantly increased tissue concentration of carnitine.

In trial II it was studied if supplementation of a commercial layers’ ration with either 500 mg L‐carnitine or 500 mg nicotinic acid or both per kg reduces the cholesterol concentration in yolk. Influence on body weight, feed intake, laying performance, serum and yolk cholesterol concentration could not be observed, but yolk concentration of carnitine was significantly increased in supplemented groups.

Trial III should clarify if the L‐carnitine content in broiler parentstock ration influences hatchability. Four groups of 1350 hens each were fed a commercial all‐mash supplemented with 0, 20, 50 and 100 mg L‐carnitine, respectively. Hatching rate was increased from 83% to 87% and from 82.4% to 85.3% in groups supplemented with 50 and 100 mg L‐carnitine, respectively, and in randomly sampled eggs of these groups carnitine concentration in yolk was higher.     

Serum thyroglobulin as a biomarker of iodine excess and thyroid disease occurrence in adults

BackgroundThyroglobulin (Tg) is considered a sensitive indicator of iodine deficiency. However, the usefulness of Tg as a biomarker of excess iodine is uncertain. The present study aimed to determine the influence of different iodine intake on serum Tg levels, evaluate the influence of thyroid diseases on the distribution of Tg, and identify the factors that may affect Tg levels.MethodsA cross-sectional survey with a total of 1208 adults was conducted in different water iodine areas in China. Urinary iodine concentration (UIC), water iodine concentration (WIC), serum Tg, thyroid-stimulating hormone (TSH), and thyroid antibodies were measured. The thyroid volumes and nodules were measured by B-scan ultrasound.ResultsBased on the WIC data, subjects were divided into three groups. Based on the median urinary iodine concentration (MUIC) data, the iodine levels were adequate, more than adequate, and excess for the WIC < 10 μg/L group, 10 μg/L ≤ WIC ≤ 100 μg/L g, and WIC > 100 μg/L groups, respectively. The median Tg was significantly higher in the excess iodine group than in the adequate iodine group and the more than adequate iodine group (14.6 μg/L vs.12.7 μg/L, P = 0.042; 14.6 μg/L vs.12.5 μg/L, P = 0.004). Multiple linear regression analysis showed that excess iodine intake, goitre, thyroid nodules, and hypothyroidism were significantly related to higher serum Tg levels.ConclusionSerum Tg level can be a promising biomarker of excessive iodine intake, but other factors, especially the presence of thyroid disease, should be considered when using this parameter.     

Whole wheat versus mixed layer diet as supplementary feed to layers foraging a sequence of different forage crops

In many cases health and welfare problems are observed in organic egg production systems, as are high environmental risks related to nutrient leaching. These disadvantages might be reduced if the layers are allowed to utilise their ability to forage to a higher degree thereby reducing the import of nutrients into the system and stimulating the hens to perform a natural behaviour. However, very little is known about the ability of modern high-producing layers to take advantage of foraging to cover their nutritional needs, and the aim of the present work was to clarify this subject. Six flocks, each of 26 hens and one cock, were moved regularly in a rotation between different forage crops for a period of 130 days. Half of the flocks were fed typical layer feed for organic layers and half were fed whole wheat. The forage crops consisted of grass/clover, pea/vetch/oats, lupin and quinoa. At the beginning of the experiment, wheat-fed hens had a lower intake of supplementary feed (wheat) and a lower laying rate, egg weight and body weight. However, after a period of 6 to 7 weeks, the intake of wheat increased to approximately 100 g per hen per day and the laying rate increased to the same level as for the hens fed layer feed. For both groups of hens egg weight and body weight increased during the remaining part of the experiment. Crop analysis revealed different food preferences for hens fed layer feed and wheat-fed hens. Wheat-fed hens ate less of the cultivated seeds, whereas the amounts of plant material, oyster shells, insoluble grit stone and soil were larger in the crops from wheat-fed hens. Floor eggs were significantly more frequent in the hens fed layer feed, whereas wheat-fed hens only rarely laid floor eggs. Irrespective of treatment, hens were found to have excellent health and welfare. We conclude that nutrient-restricted, high-producing organic layers are capable of finding and utilising considerable amounts of different feed items from a cultivated foraging area without negative effects on their health and welfare.     

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.     

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.     

Interactions of flavin containing monooxygenase 3 (FMO3) genotype and feeding of choline and rapeseed cake on the trimethylamine (TMA) content in egg yolks of laying hens

To evaluate the relationship between the FMO3 genotype and dietary trimethylamine (TMA) precursors on TMA-N content in eggs, laying hens were fed with choline (500 and 4000 mg/kg diet) and, in a later trial, with rapeseed cake (0, 100 and 300 g/kg diet). Hens were genotyped for non-synonymous A/T polymorphism at position nt1034 of the cDNA of the FMO3 gene, which is associated with elevated TMA-levels in egg yolks. Genotypes were equally distributed among the experimental diets. TMA was extracted from yolks and measured as TMA-N by a colorimetric method. As expected, hens of the TT-genotype had high amounts of TMA-N in egg yolks when fed either 4000 mg choline/kg diet or the rapeseed cake diet, while hens of the AA-genotype showed low levels of TMA-N. Heterozygous AT-hens had a slightly increased level of TMA-N when fed with 4000 mg choline/kg diet but not with the rapeseed cake feed. Rapeseed cake can be fed to AA and AT hens without leading to fishy tainted eggs.