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Studies were conducted using a commercial Inovoject™ system to determine effects of in ovo feeding of dextrin and iodinated casein (IC) on hatch and posthatch growth in broilers. At ~18.5 d embryonic development, eggs were treated with 0, 240, or 480 µg IC/mL in saline (Cont, IC240, and IC480) or dextrin (Dext, DextIC240 and DextIC480). The Dext solution consisted of 18% maltodextrin and 10% potato starch dextrin; saline was the vehicle used by the company for in ovo vaccination. The volume for all in ovo treatments was 50 µL/injection. Eggs in Experiment 1 were transferred to a commercial hatcher unit whereas eggs in Experiments 2 and 3 were transferred to a research hatcher unit to assess effects of treatments on timing of hatch. At hatch, chicks were randomly selected and placed in floor pens and grown to 6 wk. In Experiment 1, there were no differences in hatch weights, but broilers provided Dext IC240 in ovo were heavier (P < 0.05) at 6 wk compared to other treatments with the exception of the Dext IC240 group. In Experiment 2, hatch weights were heavier (P < 0.05) in chicks receiving IC240 and DexIC480 treatments compared to Controls. At 6 wk, broilers in all treatments were heavier (P < 0.05) than Cont with the exception of IC480. In Experiment 3, hatch was stimulated by IC240 (in saline), but was delayed by Dext IC240. Serum analysis of β-hydroxybutyrate (µM/mL), as an indicator of ketone accumulation from fat metabolism of chicks held in chick boxes for 24 h posthatch (to simulate delay in placement after hatch), indicated that chicks in the IC240 group (that hatched earlier) had higher blood ketones compared to chicks that received Dext or DextIC240 in ovo (that hatched later). We conclude dextrin and iodinated casein (240 µg/mL) provided in ovo (~18.5 d of embryonic development) has the potential to improve chick quality and posthatch body weight by delaying or narrowing hatch window. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the effect of in ovo feeding of dextrin (Dext) and iodinated casein (IC) on hatch and early growth in broilers. Three experiments were conducted at a commercial hatchery using a commercial InovojectTM system with treatments occurring in conjunction with vaccination at transfer from incubator to hatcher units (18.5 to 19 d embryonic development). In all 3 experiments, approximately 15,000 eggs (2,500 eggs per group) were treated and transferred to a single hatcher unit. Treatments in Exp. 1 consisted of buffered saline solution alone (Control, Cont) or a dextrin solution (Dext, 18% maltodextrin, 10% potato starch dextrin) containing zero, 80, 240, 720, or 2,160 µg IC/mL. The results of this initial experiment indicated that broiler chicks at hatch that received 240 and 720 µg IC/mL in Dext were heavier (P < 0.05) compared to the other treatment groups; there were no differences in hatchability between groups. Based on these findings, subsequent studies used treatments of zero, 240, and 480 µg/mL IC in Dext or Cont. In Exp. 2, hatch weights in all treatment groups were higher (P < 0.05) compared to those receiving Cont. In Exp. 3, chicks given Dext alone or 240 and 480 µg/mL in saline weighed less at hatch compared to the other treatment groups. However, chicks provided Dext alone in Exp. 3 had less weight loss after a 24-hour holding period compared to the other groups. All treatment groups exhibited greater weight gain from one to 10 d compared to the Cont group. The results indicate that in ovo feeding of broiler embryos with Dext containing 240 and 480 µg IC/mL may have beneficial effects on broiler hatch weights and early growth rate. [ABSTRACT FROM AUTHOR]

simple and effective liquid chromatography-mass spectrometry method was devoleped for mornitoring iodinated casein (IC) in feed premixes. In this method, iodothyronines released from IC upon sample hydrolysis were used as markers. Samples were treated with NaS and hydrolyzed with Ba(OH)·HO followed by cleaned up using a SampliQ SPE cartridge. Chromatographic separation was achieved on a C column with isocratic elution using water (0.1% formic acid, v/v) and acetonitrile as the mobile phase. Ion detection was performed using electrospray ionization in positive mode using selected ion monitoring at m/z 606, 652, 732 and 778. IC levels were mornitored by qualitative analysis of the iodothyronines and quantification of thyroxine. Validation data demonstrated that the method was selective and sensitive (≤0.5 mg g) with acceptable accuracy (70.2-128.2% recovery) and precison (RSD 5.5-15.2%). [ABSTRACT FROM AUTHOR]

Two experiments were conducted with a commercial turkey company using a commercial egg injection system to investigate the effect of a dextriniodinated casein solution injected in ovo at 25 d of incubation on turkey poult hatchability, hatch weight, and growth (6 or 7 d posthatch). In experiment 1, a total of 3,900 turkey eggs (1,300 per group) were injected at 25 d of incubation with either 200 μL of a control (physiological saline) solution or a dextrin solution (18% maltodextrin and 10% potato starch dextrin) with 75 or 375 μg/mL of iodinated casein (DexIC75 or DexIC375, where Dex and IC refer to dextrin and iodinated casein, respectively). Two hundred poults from each group were neck-tagged, weighed (hatch weight), placed in a commercial turkey house within a single brooder ring, and weighed again (7 d posthatch). In experiment 2, a total of 5,200 eggs (2,600 per group) were injected with the control or DexIC75 solution. A total of 600 poults (300 per group) were neck-tagged and hatch weights were obtained, followed by placement in a single brooder ring in a commercial house and a second weighing (6 d posthatch). Eggs in experiments 1 and 2 were obtained from hen flocks that were 33 and 5 wk into the laying cycle, respectively. In experiment 1, the DexIC75 injection resulted in a 1.8% increase (P = 0.03) in hatch weight. In experiment 2, the DexIC75 treatment resulted in a 2.4% increase in hatchability (P = 0.01), a 4.3% increase in hatch weight (P < 0.001), and a 1.8% increase in 6-d poult weights (P < 0.03) compared with controls. Results of this study indicate that a solution containing dextrin and 75 μg/mL of iodinated casein injected into turkey eggs at 25 d of incubation may be used to improve early poult weights, hatchability, or both in commercial turkey production. [ABSTRACT FROM AUTHOR]

Abstract: A new and simple HPLC–MS method was developed for monitoring iodinated casein in feed premixes. In this method, feed premixes were hydrolyzed, and the iodotyrosines thus released were analyzed. Sample pretreatment included precipitation of transition metals ions with Na2S, hydrolysis with sodium hydroxide, and cleaning up with an Oasis SAX cartridge. Gradient elution was carried out on a C18 column with water (containing 0.1% formic acid) and acetonitrile. Ion detection was performed using ESI positive SIM at m/z 262, 308, 388, and 434. Iodinated casein levels were monitored by qualitative analysis of the iodotyrosines released upon sample hydrolysis and by quantifying the 3,5-diiodotyrosine released. The validation data demonstrated that the method was selective and sensitive (≤0.2mgg−1) for iodinated casein and had acceptable accuracy (recoveries: 81.3–106.7%) and precision (RSD: 1.7–16.0%). [Copyright &y& Elsevier]

Abstract: In this paper, a new method for separation, identification and quantitation of iodotyrosines and iodothyronines [3-monoiodo-L-tyrosine (MIT), 3,5-diiodo-L-tyrosine (DIT), L-thyronine (T0), 3,5-diiodo-L-thyronine (T2), 3,5,3′-triiodo-L-thyronine (T3) and 3,3′,5,5′-tetraiodo-L-thyronine (T4)] was described by using capillary electrophoresis with photodiode-array ultraviolet–visible detection (CE-UV). The certain influence factors were systematically investigated, including the type, concentration and pH of buffer, and additive. We found that 10mM sodium borate running buffer (pH 8.5) containing 0.10mM β-CD as additive reagent allowed the best instrumental conditions for the optimum separation of the iodotyrosines and iodothyronines. Under optimized conditions, the analytical time was within 6min, using an uncoated fused-silica capillary of 75μm inner diameter with an effective length of 30cm. The reproducibility of the migration time and peak area was less than 0.6% and 6.8%, respectively. A linear range from 10–1000μg/mL and low limits of detection from 1.3–3.4μg/mL were obtained at the detection wavelength of 280nm. Our preliminary results show that the method is well suitable for determination of the hydrolysate of iodinated casein. [Copyright &y& Elsevier]

This paper reviews and presents data suggesting that the use of thyroxine (T4) to induce moult in poultry may be a viable alternative to previous methods involving feed withdrawal or feed avoidance. Studies completed in wild and domestic avian species have indicated that T4 is associated with the natural moulting process. Four experiments, spanning the range from using a purified, injectable form of T4 to a cost effective commercially available product, iodinated casein (economical source of T4) that can be fed to hens via a standard poultry ration, are presented. Since hens have full access to the diet during the induced moult, it is hoped that the procedure will be acceptable both to the poultry industry and to organizations concerned about the welfare of birds during this period of their annual cycle. [ABSTRACT FROM PUBLISHER]