Eggs Of Laying Hens Research Articles

137 Dietary Supplementations of Ethanolamine and Serine Enhance Docosahexaenoic Acid Deposition in Eggs of Laying Hens

Abstract Enrichment of docosahexaenoic-acid (DHA) into eggs of laying-hens may be limited by the availability phospholipids as a deposition sink. The present study was to determine if dietary supplementations of phospholipid-component molecules or synthesis-enhancers: choline, serine, and ethanolamine could elevate phospholipid and DHA enrichment in the eggs and tissues of hens. A total of 50-White-Leghorn-Shavers (42-wk old) were individually caged and divided into 5 groups (n = 10/group). The 5 groups of hens were fed the following diets for 3 wk: Diet-1 = a corn soybean-meal basal-diet, Diet-2 = Diet-1 + 4%-microalgae (Aurantiochytrium, Heliae, Gibert, AZ, 1.81 g-DHA/kg) + choline-chloride (26.3 g/kg diet, 60% purity, DSM-Co., Basel, Switzerland), Diet-3 = Diet-2 + 1.41% of L-serine (100% purity, Ajinomoto-Co., Inc., Kawasaki, Japan), Diet-4 = Diet-2 + 100 mg of ethanolamine/kg (99% purity, Sigma-Aldirch-Co., St Loius, MO), and Diet-5 = Diet-3 + 100 mg of ethanolamine/kg. At the end of study, eggs, liver, ovary, and adipose samples were collected from 6 hens/group for biochemical analysis. Data were analyzed by one-way ANOVA. Compared with Diet-1, Diet-2 enhanced (P < 0.05) DHA concentrations in egg yolk and liver by 213 mg/egg and 2.98 mg/g tissue, respectively, but decreased (P < 0.05) total phospholipid-concentrations of yolk and liver by 50%, and hepatic-mRNA levels of elongases-2/5 and desaturases-4/6 by 25–50%. Compared with Diet-2, Diet-5 enhanced (P < 0.05) DHA (by 20%) and phospholipid (by 40%) concentrations in the egg yolk, and upregulated (P < 0.05) lipid-metabolism genes involved in the citicoline (CDP, up-to-3-fold) and CDP-ethanolamine (up-to-2.5-fold) pathways in the liver and ovary-tissue. In comparison, Diets-3 and 4 resulted in only 3–11% higher (P < 0.05) DHA-concentrations in the liver over Diet-2. In conclusion, feeding hens a high DHA and choline diet enriched DHA in the egg yolk and down-regulated lipogenesis-gene-expression in the tissues. Supplementing the diet with extra-serine and ethanolamine further-enhanced the DHA enrichment in the egg yolk and restored the high DHA-mediated changes in the gene-expression. (Supported in part by DOE-MAGIC-grant DE-EE0007091, USDA-grant 2019-69012-29905, and Cornell-University-Hatch-grants NYC-127419/127302).

Analytical Procedures for the Determination of Aflatoxin B1 in Eggs of Laying Hens Using Immunoaffinity Columns and Liquid Chromatography with Post-Column Derivatisation and Fluorescence Detection

An analytical procedure for the determination of aflatoxin B1 in eggs was introduced and validated in laboratory 1. The method consisted of the extraction of aflatoxin B1 from a sample, purification of the extract with solvents, immunoaffinity column cleanup and the determination by liquid chromatography with post-column bromination and fluorescence detection at λex = 362 nm and λem = 425 nm. The method was transferred to laboratory 2, where it was modified and validated. The limit of detection (LOD) and limit of quantification (LOQ) obtained in laboratory 1 were 2 and 6 ng/kg, respectively, and 2 and 5 ng/kg in laboratory 2, respectively. The repeatability of measurements in laboratory 1, represented by differences between results of duplicate measurements, was 10 ng/kg at the contamination level of 50 ng/kg. At the same concentration level, the standard deviation (sR) and the relative standard deviation (RSDR) for the within-laboratory reproducibility were 5.5 ng/kg and 11 %, respectively, and the measurement uncertainty was ±10 ng/kg. The mean recovery was 70 %. In laboratory 2, the repeatability of measurements at the contamination level of 20 ng/kg, represented by the standard deviation (sR), repeatability (r) and relative standard deviation (RSDR) was 4 ng/kg, 11 ng/kg and 20 %, respectively, and the recovery was 67 %. The results indicate that the procedures are suitable for the determination of aflatoxin B1 in eggs and can be implemented for the routine analysis. Using the procedure validated in laboratory 1, 25 samples from farms in Slovenia were analysed. In none of the analysed samples, aflatoxin B1 was detected.

Residues of Ampicillin in Eggs Following Oral Administration

Residues in sodium ampicillin (AMP) in eggs of laying hens were determined by a microbiological method of diffusion in agar after oral therapy with an esophageal probe with a dose of 150 mg / kg / day for 5 days. The limit of quantification is 0.02 μg / g in albumen and yolk. The duration of the elimination of AMP in the albumen and yolk is 2 days after stopping the treatment.

Study of Enrofloxacin Depletion in the Eggs of Laying Hens Using Diphasic Dialysis Extraction/Purification and Determinative HPLC-MS Analysis

A study of the depletion of enrofloxacin residues in eggs was carried out using a diphasic dialysis procedure for the extraction of fluoroquinolone residues from the matrix. Enrofloxacin was administered to laying hens through the intramuscular route (15 mg/day) and orally (12 mg/day). After daily collection, the egg albumen and the egg yolk were separated, and the residue levels were determined using an HPLC-MS (API-ESI) method. The enrofloxacin and ciprofloxacin peaks gradually increased until the fifth day, because the drug was employed for 5 days. However, differences were observed in the depletion curves of enrofloxacin and its metabolite when both parts of the egg and the mode of administration were considered.

Transferring and distributing profiles of p,p'-(DDT) in egg-forming tissues and eggs of laying hens following a single oral administration.

Laying hens were administered orally with a single dose of p,p'-(DDT) (1 mg/kg bodyweight). The concentrations (microg/g) of DDT or its metabolites, p,p'-(DDE) and p,p'-(DDD), in the main tissues involved in egg formation (blood, liver, ovary, and oviducts) and egg yolk, collected 1 day after DDT dosing, were determined by normal-phase high-performance liquid chromatography. The limits of detection were 0.04 microg/g for DDT, 0.07 microg/g for DDE and 0.06 microg/g for DDD. In extractable fats from the above tissues and egg yolk, DDT and DDE were transferred/distributed throughout the tissues and egg yolk. DDD was detected only in the liver. The findings indicate that DDT is metabolized instantaneously to DDE/ DDD in the hen's body and they are transferred rapidly into the egg-forming tissues and egg yolk. Among the four tissues and yolk fats examined, the DDT levels were high in the ovary, oviduct and egg yolk; the DDE levels were high in the liver, ovary and oviduct and lowest in the yolk (P < 0.01).

Residues of Carbaryl and Two of Its Metabolites in Eggs of Laying Hens Treated with Sevin® for Northern Fowl Mite Control by Dipping

White Leghorn laying hens were treated with carbaryl [Sevin®, 1-naphthyl-N-methylcarbamate] by dipping in a .5 or 1.0% (active ingredient) water suspension of an 80% commercially available wettable powder formulation. Residues of carbaryl and two of its metabolites, 1-naphthol and N-hydroxymethyl carbaryl, were detected in eggs within 1 day and reached maximum levels 5 to 7 days after dipping. After that time residues steadily declined but were still detectable 56 days posttreatment in the eggs of the high-dose hens. At no time during the study did total residues in eggs exceed the current. 5 ppm egg tolerance for carbaryl and its metabolites.

Selenium Deposition in Tissues and Eggs of Laying Hens Given Surplus of Selenium as Selenomethionine

Forty-eight Norwegian bred White Leghorn chickens were divided into 6 groups and fed a basal diet containing 0.30 mig Se/kg supplemented with 0, 0.1, 0.5, 1.0, 3.0 or 6.0 mg Se/ kg in the form of selenomethionine for 18 weeks. A supplement of only 0.1 mg Se/kg induced significantly higher selenium concentrations in breast muscle and eggs, particularly in the egg white. The increase of selenium in the tissue and egg was proportional to the amounts of selenomethionine added to the feed. In the group given 6.0 mg Se/kg, the selenium concentrations in all tissues and eggs analysed ranged from 4.8 to 7.3 μg Se/g. No signs of toxic effects were observed even at the highest intake of selenium. Excess supply of selenium as selenomethionine to chickens was shown to be more potent than sodium selenite in raising the selenium concentration in tissues and eggs. A supplementation up to 10 times the requirement did not increase the levels of selenium in poultry products to such a degree that they could be considered as a potential risk for human consumption.

Residues of Stirofos (Rabon®) in Eggs of Laying Hens Treated for Northern Fowl Mite Control by Dipping ,

Laying hens were treated with a wettable powder formulation of stirofos [Rabon®, 2-chloro-l-(2,4,5-trichlorophenyl) vinyl dimethylphosphate] by dipping in a .5 or 1.0% actual ingredient (AI) water suspension of a 50% wettable powder (WP) stirofos formulation. Stirofos residues were detected in eggs within 1 day after treatment and reached maximum levels 3 days after dipping (.021 and .035 ppm in the low- and high-dose birds, respectively). After that time, levels of residues in eggs declined rapidly and no sample contained detectable quantities (<.004 ppm) of stirofos after 21 days. Dipping may be a practical control method for the northern fowl mite on chickens, because stirofos dips effectively control this mite on laying hens for at least 6 weeks and because resulting residues in eggs are well below established tolerances.

Residues of Gardona in the body tissues and eggs of laying hens exposed to treated litter and dust boxes for control of external arthropod parasites.

Gardona® (2-chloro-1-(2,4,5-trichlorophenyl) vinyl dimethyl phosphate) placed in dust-bath boxes and in floor litter in chicken houses for 4 weeks produced maximum residues of 0.058 ppm in the back skin and 0.048 ppm in the body fat of chickens. Also, 6 samples of egg white contained residues ranging from 0.003 to 0.022 ppm, and 1 sample of egg yolk had a residue of 0.003 ppm. No residues were detectable in eggs or tissues the 2nd week after the insecticide was removed from the houses. Gardona, as used, had no apparent ill effect on the birds.