Automatic weighing of individual laying hens in aviary housing systems

Administration of a goitrogen (methimazole) and a low iodine diet to rats over a two-week period resulted in hypothyroidism and thyroid hyperplasia compared with controls (control: total serum thyroxine (T4) 66 +/- 4 nmol/l, thyroid weight 5 +/- 1 mg/100 g body weight; experimental: T4 undetectable, thyroid weight 27 +/- 4 mg/100 g body weight after 2 weeks of treatment; mean +/- S.D., n = 10). Immunohistochemistry carried out using a specific endothelial cell marker, CD31, and morphometric analysis (point counting of immunopositive cells) revealed that the progression of goitre in the rat thyroid is accompanied by an increase in capillary endothelial cell growth (neovascularisation). Fibroblast growth factor-2 (FGF-2) immunohistochemistry revealed widespread staining for the protein in the follicular cells of control glands. Less intense staining was found in the stroma and follicular cell nuclei. During hyperplasia and subsequent neovascularisation there was a progressive increase in the FGF-2 immunoreactivity at all locations during the two-week treatment period. Thrombospondin-1 (TSP1) immunoreactivity in the control rat thyroid was found in the stroma and in the endothelial cells, while weak follicular cell staining was also present. In the goitrous rat thyroid the TSP immunoreactivity was present after 1 week of treatment in the endothelial cells and most follicular cells, whilst stroma localisation was weak. After week 2 of treatment the endothelial cell and stromal localisation was no longer apparent, although a follicular localisation was still present. Transforming growth factor-beta 1 (TGF beta 1) immunoreactivity was present in the cytoplasm of a minority of the follicular cells in control rat thyroids, while their nuclei were unstained. In the goitrous rat thyroid an increase intensity of staining for TGF beta 1 was seen in all follicular cells, many of which now also demonstrated immuno-positive nuclei, within one week of goitrogen administration. These results show that in the hyperplastic thyroid increases in FGF-2 and TGF beta 1, and decreases in TSP1 accompany angiogenesis. These factors may interact in an autocrine/paracrine relationship to stimulate the neovascularisation that occurs during goitre formation.     

Cestodosis in battery-housed laying hens

Cestodosis in battery-housed laying hens severely reduced egg production particularly at the time of peak production. Hens were able to consume large numbers of Musca domestica, the intermediate host of Choanotaenia infundibulum following the use of an aerosol insecticide to control flies. A considerable discharge of cestodes followed the use of "Lintex" in the feed resulting in a marked improvement in egg production. The use of an insect growth regulator in the feed showed promise in controlling the breeding of flies.     

Fluoride tolerance of laying hens

Myogenic precursor cells withdraw irreversibly from the cell cycle as they differentiate into mature myotubes. Cell cycle exit occurs early during the differentiation program and is required for normal expression of the contractile phenotype. Differentiated myocytes also display a decreased propensity to undergo apoptotic cell death. The upregulation of the cyclin-dependent kinase inhibitor p21 and the dephosphorylation of retinoblastoma protein (pRb) appear to be critical regulatory events for the establishment of both the postmitotic and apoptosis-resistant states. The coordinated regulation of cell proliferation and death provides the developing embryo with a mechanism for controlling muscle mass and thereby the size of individual motor units.     

Threonine requirements of laying hens

In order to determine the Thr requirement of laying hens, two experiments were conducted using laying performance and plasma Thr concentration as parameters. At 29 and 39 wk of age, 100 and 600 laying hens in Experiments 1 and 2, respectively, with average BW and high egg production rate, were randomized, housed in individual cages, and given free access to water and experimental diets with five graded levels of Thr: 0.31, 0.39, 0.46, 0.54, and 0.61% for 21 d in Experiment 1 and diets with 0.31, 0.36, 0.41, 0.46 and 0.51% Thr for 58 d in Experiment 2. On the last day of the experiment, blood samples were taken for determination of plasma amino acid concentration. Feed intake and daily egg mass increased and then decreased linearly as dietary Thr increased. Plasma Thr increased slowly, then sharply with increasing dietary Thr levels. Using the broken-line model, the Thr requirements were estimated to be 0.425, 0.428, and 0.430% or 453, 456, and 458 mg/hen per d in Experiment 1 and 0.395, 0.404, and 0.400%, or 457, 467, and 462 mg/hen per d, in Experiment 2, for egg mass, feed efficiency, and plasma Thr concentration, respectively. These results indicate that the Thr requirements expressed as milligrams per hen per day as determined by plasma Thr concentration agree with those of laying performance.     

Fucoxanthin metabolites in egg yolks of laying hens

Feeding experiments were conducted with White leghorn laying hens fed a carotenoid depleted control diet (containing some zeaxanthin and lutein) or this diet supplemented with 15% seaweed meal of established carotenoid composition. Egg yolk colour was estimated by use of a Roche Yolk Colour Fan and by detailed quantitative and qualitative carotenoid analysis of individual eggs of three laying hens during 4 weeks. Identification of the carotenoids included HPLC. VIS, MS, 1H NMR data and partial synthesis. The results confirmed that fucoxanthin, the major carotenoid in seaweed meal, is not transferred to the yolk. However, fucoxanthin gave rise to the metabolites fucoxanthinol, fucoxanthinol 3'-sulphate and paracentrone, that are ascribed to enzymatic modifications occurring in the hens. The difuranoid auroxanthin encountered in the egg yolk was ascribed to violaxanthin and/or its furanoid derivatives present in the seaweed meal. Colour of individual yolks varied considerably. The pigmentation level is discussed.     

Detection of Salmonella enteritidis in suspected flocks of laying hens

In the present paper, we report that an inositolphosphoglycan (IPG), derived from a Trypanosoma cruzi glycoinositolphosphoceramide (LPPG), is able to inhibit ACTH-mediated accumulation of a glucocorticoid, cortisol, in calf adrenocortical cells. This IPG is also able to inhibit the stimulation by ACTH of the production of the main glucocorticoid, corticosterone and the main mineralocorticoid, aldosterone, in rat adrenocortical cells. Nitrous acid deamination confirmed that IPG is responsible for this inhibition. In order to study the involvement of glycosylphosphatidylinositol (GPI) in ACTH response in rat adrenal cortex, the activation of a phospholipase that hydrolyzes GPI (GPI-PLC) was evaluated. It was found that the release of alkaline phosphatase, a GPI-anchored enzyme, to the extracellular medium is increased in rat adrenocortical cells by ACTH treatment. In addition, ACTH stimulates the release of ceramide from the glycoinositolphosphoceramide purified from T. cruzi. These data suggest that ACTH activates a GPI-PLC in rat adrenal cortex, which is in agreement with our previous data in calf adrenocortical cells; thus, the hydrolysis of GPI provoked by ACTH takes place in different mammals and the IPG released could inhibit ACTH-mediated synthesis of aldosterone, corticosterone and cortisol.     

Genetic parameters of survival to the different stages of embryonic death in laying hens

Heritabilities and genetic correlations of fertility (FERT) as well as of susceptibilities to early (EEM), medium (MEM), and late (LEM) embryonic mortalities conditional on fertility and survival to earlier stage(s) of embryonic mortality were estimated with a general linear model using a logistic link function on 59,794 eggs obtained from 6,480 hens issued from 228 sires and 1,053 dams. Estimated heritabilities of FERT, EEM, MEM, and LEM were, when estimated from sire and dam components, respectively, equal to 0.09 and 0.31, 0.09 and 0.25, 0.07 and 0.20, and 0.05 and 0.18; whereas estimated heritabilities of hatchability of fertile eggs were 0.05 and 0.15, respectively, when estimated from the sire or dam components. Most genetic correlations between FERT, EEM, MEM, and LEM were favorable with the exception of correlations between FERT and MEM and between EEM and MEM when estimated from the sire component. These results show the theoretical interest of distinguishing the three stages of mortality.     

Effect of calcium propionate on performance of laying hens

Laying hens kept in individual cages were fed a practical diet supplemented with 0, 0.1, 0.2., 0.4, or 0.8% calcium propionate for a six-week period. Rate of egg production, average egg weight, feed consumption, and body weight change during the experiment were not significantly affected by and dietary treatments. Liver weight, moisture content and fat content were also no significantly affected by dietary treatments. The results show that the performance of normal hens is not changed by calcium propionate supplementation.     

Rapeseed and rapeseed meal as components in diets of laying hens

In an experiment with 405 Hisex white hens rations with 5-20% low glucosinolate rapeseed (RS) or rapeseed meal (RSM) of 00 quality were used. Feed intake, egg production, individual egg weight and live weight gain were reduced in hens fed 5-20% RS and 10-20% RSM. There was a positive correlation between the RS proportion in the ration and the thyroid weight as well as the iodine content of the thyroid. The relation between the iodine content related to one gram of thyroid and the RS proportion was not significant. There were not any significant differences between the RSM groups and the iodine content of the thyroid. The T3 and T4 concentrations in the blood plasma was independent of the RS- or RSM-proportion in the diet. The outward egg quality was not influenced by feeding. The Haugh units were lower when RS or RSM were offered. The fatty acid pattern of the yolk was changed by RS or RSM feeding, particularly the proportion of oleic acid increased. We concluded from the results, RS cannot be recommended for feeding white hens and only a maximum of 5% RSM should be administered.     

Influence of Fusarium-infected corn and F-2 on laying hens

Diets containing either Fusarium-infected corn supplying 25 and 100 p.p.m. of F-2 (zearalenone) or purified F-2 at these levels did not adversely influence the reproductive performance of laying hens. In trial 1, no deleterious effects were observed for 20- and 36-week body weights, age at first egg, egg weight, albumen height, shell deformation, fertility or hatchability when Fusarium-infected corn was fed to 20-week-old pullets for 28 days. Percent hen-day egg production of birds fed Fusarium-infected corn supplying 25 and 100 p.p.m. of F-2 was superior (P less than or equal to 0.5) to egg production of nontreated controls. In trial 2, three replications of ten adult Leghorn hens were evaluated under five dietary treatments: (1) 16.7% protein basal; (2) basal plus Fusarium-infected corn (25 p.p.m. of F-2); (3) basal plus 25 p.p.m. of (purified) F-2; (4) basal plus Fusarium-infected corn (100 p.p.m. of F-2); (5) basal plus 100 p.p.m. of (purified) F-2. Difference between dietary treatments for 14-day pre-treatment, treatment and post-treatment periods were nonsignificant for 42- and 44-week body weights, egg production, egg weights, fertility and hatchability. Body weights of chicks from hens fed F-2 diets were not significantly different from those of chicks from hens fed the basal diet.     

Absorbability of sulphamonomethoxine and sulphadimethoxine administered via food of laying hens

We present a case of amiodarone pulmonary toxicity, special emphasis is given to the radiological features because the presence of pulmonary nodules with interstitial and alveolar abnormalities. Due to a treatment with amiodarone, the patient developed few symptoms, with a low maintenance dose of 200 mg/day.     

Effect of acute heat stress on amino acid digestibility in laying hens

An experiment was conducted to determine the effect of acute heat stress exposure on amino acid digestibility in laying hens. A total of 30 commercial laying hens were singly housed in an environmentally controlled facility, fed a standard laying ration, and exposed to a constant thermoneutral temperature (21 C) for 12 d. The hens were then randomly fed one of three diets (10 hens per diet) and exposed to three consecutive temperature periods (8 d each), which consisted of: 1) a constant 21 C temperature, 2) a cycling temperature of 35 C for 12 h and 29 C for 12 h, and 3) a constant 21 C temperature. The three isonitrogenous (18% CP) diets fed were: 1) a corn-soybean meal diet, 2) a corn-soybean meal diet containing 15% meat and bone meal, and 3) a corn-soybean meal diet containing 5% alfalfa meal and 20% wheat bran. Excreta were collected from all hens during the last 4 d of each temperature period and apparent amino acid digestibility was determined. There was a significant diet effect (P < 0.05) on amino acid digestibility. Digestibility of amino acids in Diet 2 (corn-soybean meal/meat and bone meal) was higher (P < 0.05) than in the other two diets. In addition, digestibility of amino acids in Diet 3 (corn-soybean meal/alfalfa meal/wheat bran) was significantly lower (P < 0.05) than in Diets 1 or 2. Heat stress generally had no significant effect on amino acid digestibility except for His and Lys digestibility. Histidine digestibility was higher during the heat stress period than during the initial and recovery thermoneutral periods, whereas Lys digestibility was higher during the heat stress period than during the initial thermoneutral period. These results indicated that acute heat stress (8 d) had no adverse effects on dietary amino acid digestibility in laying hens.     

Rapeseed meal glucosinolates: metabolism and effect on performance in laying hens

Two experiments were conducted with Hyline Leghorn hens to study the metabolism and detrimental effects of rapeseed meal (RSM) glucosinolates. Raw Target RSM was force fed to 12 hens which were killed after varying time intervals (15 min., 30 min., 60 min.) and the contents of areas of the digestive tract (crop; proventriculus and gizzard; duodenum and ileum) were analyzed for the presence of hydrolysis products of progoitrin. Nitrile compounds were found to be present in all areas of the digestive tract in much larger relative amounts than was oxazolidinethione. When commercially prepared RSMs of varying glucosinolate content were fed to laying hens at a 50% level of dietary inclusion, high glucosinolate-content RSM depressed egg production (P less than 0.05) more than low glucosinolate-content RSM but did not cause a greater frequency of liver hemorrhage. Histological examination of liver tissues from hens suffering liver hemorrhage revealed a severe reticulolysis.     

Influence of dietary osteolathyrogens on the eggshell quality of laying hens

1. Laying hens were fed osteolathyrogens, either semicarbazide hydrochloride at 0.3 or 0.4 g/kg or beta-aminopropionitrile fumarate at 0.5 or 0.6 g/kg diet to examine their effects on eggshell quality. 2. Shell quality characteristics considered for evaluation were shell surface area, shell thickness, shell weight, percentage shell, shape index and the specific gravity of eggs. Measurement of shell quality traits revealed that the hens fed osteolathyrogens laid eggs with significantly lower specific gravities and proportion of shell by weight. These differences were not explained by differences in shell thickness or weight or the shape index of eggs. 3. It was concluded that osteolathyrogens cause hens to lay eggs with poor shell quality and such eggs are weak and fragile.     

Health of laying hens in an aviary system over five batches of birds

Mortality and health were studied in laying hens kept in an aviary system on a practical scale. All management inputs were done by university staff. Five batches of birds (trials) during a period of 6 years with approximately 4,700 birds per trial were included in the study. The aviary was a three-tiered "Marielund" system divided into 4 pens. Three hybrids, reared on litter with access to perches, were used; Lohmann Selected Leghorn (LSL), Lohmann Brown (LB) and an experimental cross (SLU-1329). The hens were not beak-trimmed. The stocking density was 17 hens/m2 ground floor. Mortality varied between pens and between batches, ranging from normal rates of 3.4% to 7.8%, except in LSL in Trial 2 and LB in Trial 3 where it was much higher (15.6% and 20.9%, respectively). The dominating causes of total mortality were salpingitis and cannibalism. Coccidiosis and lymphoid leucosis contributed significantly to mortality in Trial 2. An infestation with fowl mites (Dermanyssus gallinae) occurred in Trial 1. Feather loss was most severe in LB. Keel bone deviations were recorded at increasing levels by age. Foot abscesses occurred more frequently at 35 weeks than at 55 weeks. LSL was more severely affected than LB and SLU-1329.     

Responses of laying hens to forced molt procedures of variable length with or without light restriction

The importance of the length of the rest period and of photoperiod as components of the forced molt procedures was evaluated in 650- and 560-d-old Lohman hens. The procedure included an 8-d feed withdrawal phase and rest periods varying from 0 to 35 d, during which the birds were fed for maintenance only. In the first trial, forced molt was applied with or without omission of artificial illumination. The rest period varied between 2 and 20 d. In the second trial, all treatments included omission of artificial illumination, and a variable rest period between 0 and 35 d. Egg production ceased, after 4 to 5 d of feed withdrawal and resumed 8 to 15 d after the end of the rest period, without any consistent response to its length. Forced molt stimulated egg production rate and diminished its age-dependent rate of decline, reduced the proportion of broken and shell-less eggs, and improved shell quality. Following wide oscillations proportional to the length of the rest period, egg weight stabilized at levels similar to that of the unmolted controls. Feed intake was stimulated by forced molt to levels exceeding those of the control hens. Body weight increased during the postmolt period to levels slightly exceeding those of unmolted controls. Results of one trial show that omission of artificial illumination was essential for the full expression of the molt responses. In the other trial, production rate and shell quality were improved and the percentage of broken eggs was reduced when the length of the rest period was increased. Maximal improvements appears to have been reached with rests period of 14 to 21 d.     

The effects of 1,25-dihydroxycholecalciferol and phytase on the natural phytate phosphorus utilization by laying hens

Biochemical changes that are associated with the growth phase of stretch-induced skeletal muscle hypertrophy are better understood than events that maintain the increased muscle mass. One purpose of this study was to determine whether changes that occur during the period of rapid muscle hypertrophy persist during periods when muscle growth plateaus or the rate of enlargement slows. Serum response factor (SRF), myogenin, MyoD, and actin mRNA expression patterns were examined. SRF protein interactions with serum response element-1 (SRE1) of the chicken skeletal alpha-actin gene were also characterized. Anterior latissimus dorsi (ALD) wet weight (132% and 122%) and total RNA concentration (29% and 19%) increased after 2 and 3 weeks of stretch overload, respectively. Myogenin mRNA per microgram RNA increased after 3 (775%), 6 (1073%), 14 (227%), and 21 days (133%) of stretch overload. At 6 days, myogenin mRNA levels were increased in the distal, middle and proximal regions of the ALD. Serum response factor (SRF) mRNA per microgram total RNA was not increased after 2 or 3 weeks of stretch overload. MyoD and skeletal alpha-actin mRNAs per microgram total RNA were also unchanged after 2 and 3 weeks of stretch. Gel mobility shift assays demonstrated that SRF bound to SRE1 from 14-day-stretched ALD nuclear extracts had an increased mobility compared to control, and this difference in mobility was maintained in nuclear extracts from ALD muscle whose mass was declining. These results indicate that the expression of myogenin mRNA and total RNA remains elevated during either slow or maintenance periods of stretch-induced increases in ALD mass, when SRF mRNA has returned to control levels. Additionally, stretch-induced alterations in SRF binding to SRE1, from the skeletal alpha-actin promoter, occur regardless of the rate of stretch-induced growth.     

Organoleptic evaluation of eggs produced by laying hens fed diets containing graded levels of flaxseed and vitamin E

Eighteen-week-old laying hens were fed diets containing 0, 10, or 20% ground flaxseed and 10 or 100 IU vitamin E/kg diet, in a factorial arrangement. When birds were 60 wk of age, eggs were collected from various treatments and used in taste panel studies. All studies involved freshly boiled eggs. In Experiment 1, four separate panels were conducted to obtain information on egg aroma, egg flavor, presence of any off-flavor, and overall acceptability of the egg. Pooled data showed a very significant difference among panelists for all attributes tested (P < 0.01) and off-flavors were detected in eggs from hens fed 10 and 20% flaxseed with 10 mg vitamin E/kg. In Experiment 2 panelists were asked to evaluate egg aroma, yolk flavor, and overall acceptability in eggs from birds fed the lowest level of vitamin E with 0 or 10% flaxseed, and birds fed 20% flaxseed and 10 or 100 mg vitamin E/kg. The highest ratings for egg aroma, yolk flavor, and overall acceptability were for the control eggs. There was a significant reduction in overall acceptability as flaxseed concentration increased (P < 0.05) and an interesting and significant (P < 0.05) decline in overall acceptability for birds fed 100 vs 10 IU vitamin E/kg diet in eggs for birds fed 20% flaxseed. In a third study, there was an indication of preference for eggs from birds not fed flaxseed, when the diet contained 10, rather than 100 IU vitamin E/kg diet. These data suggest that high (> 10%) levels of flaxseed used in the bird's diet will result in some decrease in overall egg acceptability as assessed by aroma and flavor. These effects seem to be accentuated by using high levels of vitamin E in the bird's diet.     

An association of hardness of water with incidence of fatty liver syndrome in laying hens

Twenty-one samples of water were collected from commercial egg production farms in Georgial with or without a history of fatty liver syndrome. These samples plus a sample of water from the University of Georgia Poultry Farm were analyzed for various mineral elements by atomic absorption, direct reading emission spectroscopy and by neutron activation. Water samples from farms with a history of fatty liver syndrome had signficantly more calcium, magnesium, strontium, sodium, iron and barium than water samples from farms reporting no significant problem with fatty liver syndrome. Levels of manganese, boron, copper zinic and aluminum were not significantly different. Although the results do not prove that water quality is the cause of the disease, they do demonstrate an association of hardness of water with fatty liver syndrome that should be further investigated.     

Research note: responses of laying hens on saline drinking water to dietary supplementation with various zinc compounds

Production variables, eggshell defects, eggshell quality, the concentration of calcium-binding protein (CaBP), and the activity of carbonic anhydrase (CA) in the shell gland mucosa were determined in hens receiving town water (10 mg Na/L), or town water supplemented with 2 g NaCl/L (796 mg Na/L). Five treatments were examined. Control hens received town water and a proprietary layer mash containing .17% Na. The remaining four treatments received the water containing NaCl (2 g/L). Hens of Treatment 2 were fed the proprietary layer mash and those of Treatments 3, 4, and 5 received, respectively, the layer mash containing supplements of Zn-methionine (Zinpro-200; .5 g/kg), Zn sulfate (ZnSO4.7H2O; .46 g/kg), or chelated Zn-EDTA (.54 g/kg) to supply the same concentration of Zn (.1 g/kg). The treatments were applied for 6 wk. Hens receiving the saline drinking water without any dietary Zn supplement produced significantly (P < .05) more eggs with shell defects than hens receiving the town water. This increase in the incidence of eggshell defects was associated with significant reductions in eggshell breaking strength, the concentration of CaBP, and the activity of CA. Supplementing the saline drinking water with any of the three Zn compounds significantly reduced the incidence of eggshell defects and in some cases improved shell breaking strength, the concentration of CaBP, and the activity of CA.