Laying hens prefer softer over harder mineral-based pecking stones and peck them more at the end of the light period.

Mineral-based pecking stones (PS) are edible enrichments for poultry that comprise a high proportion of calcium. We aimed to determine whether laying hens prefer a Soft (easier to ingest) versus a Hard mineral-based PS with the same calcium content, if pecking at PS follows a diurnal pattern similar to calcium appetite, and whether the PS affects eggshell quality. Shaver White laying hens housed in groups of 3 in furnished cages (N = 38) were given either a Hard or Soft PS for 15 days, followed by a 6-day washout period of no PS, and then the opposite PS type for an additional 15 days (Phase 1).

Strain differences and effects of different stocking densities during rearing on the musculoskeletal development of pullets.

There are few published studies on the effect of stocking density (SD) of pullets, particularly between different genetic lines. The objectives of this study were to determine if strain or SD affects musculoskeletal development of pullets and determine any impact on the productivity and keel bone health of adult hens. Lohmann Selected Leghorn Lite (LSL), Dekalb White (DW), and Lohmann Brown (LB) pullets were reared at 4 different SD (247 cm/bird, 270 cm/bird, 299 cm/bird, and 335 cm/bird) in large cages furnished with elevated perches and a platform.

The effect of space allowance and cage size on laying hens housed in furnished cages, Part II: Behavior at the feeder.

Standards for feeder (a.k.a.

Effect of space allowance and cage size on laying hens housed in furnished cages, Part I: Performance and well-being.

There are few published data on the effects of housing laying hens at different densities in large furnished cages (FC; a.k.a.

Development of perching behavior in 3 strains of pullets reared in furnished cages.

Furnished rearing cages are becoming more widely available to replace conventional systems for pullets. To date, there is little information on how pullets develop perching behavior in furnished cages or how this varies among strains. The objective of this study was to evaluate the use of perches and a platform in a commercial furnished rearing "Combi-Cage" system by 3 pure-bred heritage strains of pullets (Rhode Island Red, Columbian Rock, and White Leghorn).

Comparison of selenium levels and sources and dietary fat quality in diets for broiler breeders and layer hens.

Two experiments were carried out with broiler breeders (experiment 1) and laying hens (experiment 2) to study the effects of Se sources, in interaction with dietary level of Se or dietary fats on performance, Se incorporation into tissues (blood, liver, breast muscle, and egg) and eggs, hatchability, and glutathione peroxidase (GPX) activities in tissues and blood. Both experiments involved a 3 x 2 factorial arrangement of 3 Se sources (selenite, Se yeast, or B-Traxim Se) and either 2 levels of each source (0.1 or 0.

Rearing photoperiod and abrupt versus gradual photostimulation for egg-type pullets.

1. Lohmann White and Lohmann Brown egg-type hybrids were reared on 6-, 8-, 10- or 12-h photoperiods, transferred to 12.5 h at 18 weeks and then given weekly increments to reach 14 h at 21 weeks.

Green light during rearing does not significantly affect the performance of egg-type pullets in the laying phase.

Lohmann White pullets were reared in cages and illuminated with 8 h of white light at 2.6 lx or green light at 3.0 lx from commercial incandescent lamps.

Rearing and laying performance following various step-down lighting regimens in the rearing period.

It is frequently recommended that commercial laying pullets are reared on step-down lighting regimens, rather than on constant short photoperiods, to help achieve BW targets during rear and optimal performance in lay. To evaluate the effectiveness of this strategy, Shaver White pullets were maintained on 8-h day lengths or given a step-down lighting regimen from 23 to 8 h over periods of between 1 and 15 wk. Other pullets, which were initially maintained on 8 h of light, were given an abrupt increase in day length prior to transfer to step-down lighting at various ages between 1 and 13 wk.

Enrichment of eggs with lutein.

Lutein is being considered as a nutrient for prevention of macular degeneration in the aging population. Two experiments were designed to study the transfer efficiency of lutein from the layers' diet into the egg. In experiment 1, laying hens were fed corn-soy diets supplemented with 0, 125, 250, 375, 500, 625, 750, or 1000 ppm of lutein.

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.

Nuclear magnetic resonance imaging as a tool to estimate the mass of the Pectoralis muscle of chickens in vivo.

1. Nuclear magnetic resonance imaging (MRI) was used to assess the advantages of the technique in determining the size (volume) and shape of the Pectoralis muscle (Pectoralis major and minor) in broiler chickens, non-invasively and in vivo. 2.

A problem with characteristics of the thin albumen in laying hens.

Industry observations indicate that a proportion of shell eggs exhibit an uncharacteristic spreading of the thin albumen when they are broken-out for fast-food preparation. Because the height and characteristics of the thick albumen are unaffected, the eggs are classified as Grade A. Preliminary observations discounted effects of egg storage or contaminated feed.

Layer performance of four strains of Leghorn pullets subjected to various rearing programs.

Two experiments were conducted using four strains of Leghorn pullets, namely Babcock, DeKalb, H & N, and Shaver. Pullets were grown on conventional or low protein diets fortified with additional amino acids. At 18 wk of age, 64 pullets from each strain and diet treatment were transferred to individual laying cages, using eight replicate groups of four adjacently caged birds.

Broiler response to diet energy.

Male broiler chickens were fed corn-soybean diets providing 2,700, 2,900, 3,100 or 3,300 kcal ME/kg. In all experiments, each treatment was tested with three replicate groups of 30 birds grown to 49 d of age. In Experiment 1, birds consumed the various diets ad libitum whereas in Experiment 2, all birds received identical and restricted quantities of feed so as to ensure variable intakes of energy.

Broiler response to energy or energy and protein dilution in the finisher diet.

Two experiments were carried out with male broiler chickens in which diets from 35 to 49 d of age were diluted by oat hulls and sand. In one experiment only energy was diluted; in the second experiment, both energy and protein (amino acid) levels were affected. Each diet was tested with four replicate floor pens each containing 25 1-d-old birds.

alpha-Linolenic acid- and docosahexaenoic acid-enriched eggs from hens fed flaxseed: influence on blood lipids and platelet phospholipid fatty acids in humans.

This study was undertaken to examine the effects that consumption of eggs from hens fed diets containing flaxseed would have on plasma and platelet lipids of male volunteers. Feeding diets containing 0%, 10%, and 20% ground flaxseed to Leghorn pullets provided a marked progressive increase in n-3 fatty acid content as alpha-linolenic acid (alpha-LNA) (28, 261, and 527 mg/egg) and docosahexaenoic acid (DHA) (51, 81, and 87 mg/egg) but no alteration in the cholesterol concentration of the egg yolk. Twenty-eight male volunteers, divided into three groups, were fed four eggs per day for 2 wk according to a cyclic Latin-square design.

Response of broilers to feed restriction or diet dilution in the finisher period.

Two experiments were conducted to study the response of 35- to 49-day-old male broilers to either feed restriction or diet dilution. In Experiment 1, after being fed conventional starter-grower diets to 35 days of age, birds consumed either a conventional finisher diet ad libitum, or 10, 20, 30, 40, or 50% less of this diet to 49 days of age. Performance and carcass characteristics were measured from 35 to 42 days and 42 to 49 days.

The effect of dietary sodium on right ventricular failure-induced ascites, gain and fat deposition in meat-type chickens.

Experiments were carried out using various levels of sodium (Na+) from NaCl or NaHCO3 to determine: 1) the level of Na+ required to induce ascites alone or in combination with cold temperature and 2) the effect of Na+ on weight gain and fat deposition in broiler chickens. In experiment 1, there were no cases of ascites using levels of Na+, from NaCl at 0.14% to 0.

Effect of poultry by-product meal on pulmonary hypertension, right ventricular failure and ascites in broiler chickens.

We tested the hypothesis that poultry by-product meal would produce a thermogenic response (an increased requirement for oxygen) resulting in an increased incidence of pulmonary hypertension with right ventricular failure and ascites in commercial broiler chickens.Four treatment groups, each with three replicates of 40 chicks, were fed a commercial broiler starter to day 21, grower to day 35, and the following experimental diets after day 35: group 1, commercial chicken broiler finisher; group 2, commercial chicken broiler finisher with poultry by-product meal added to replace part of the soyabean meal; group 3, commercial chicken broiler finisher with poultry fat added to replace the animal-vegetable (AV) fat; group 4, commercial chicken broiler finisher with both poultry by-product meal and poultry fat added to replace soyabean meal and AV fat. On day 35, pen temperature was reduced to 15 degrees C, and on day 42 to 12 degrees C.

Regulation of androgen receptor mRNA in rat Sertoli and peritubular cells.

Regulation of 9.5-kb androgen receptor mRNA concentrations in Sertoli and peritubular cells from 20-day-old rats was studied by Northern blot analysis. Treatment of cells in vitro for 1-7 days with 300 ng/ml FSH increased androgen receptor mRNA up to 4-fold in Sertoli cells but not in peritubular cells.

Growth and development of Leghorn pullets subjected to abrupt changes in environmental temperature and dietary energy level.

Four trials were conducted to note the response of pullets to changes in environmental temperature and energy level at 56 days of age. In each trial, birds were fed diets providing either 2,500 or 3,000 kcal ME/kg throughout rearing, or with a single diet change from 2,500 to 3,000 and 3,000 to 2,500 kcal ME/kg occurring at 56 days. Each of the four diet scenarios was tested with six replicate caged groups each containing 10 pullets.

Response of laying hens to supplemental niacin.

Two experiments were conducted to investigate the effect of supplemental niacin on laying hen performance and liver fat and egg cholesterol content. In Experiment 1, 16 replicate groups of four adjacently caged birds were fed corn and soybean meal diets calculated to contain 22, 44, 66, or 132 mg supplemental niacin/kg (23.2, 38.

Diet dilution and compensatory growth in broilers.

Two experiments were conducted to note the response of broiler chickens to degrees of diet dilution from 4 to 11 days of age. In Experiment 1, broilers were fed conventional broiler diets from 0 to 4 and 11 to 56 days of age. From 4 to 11 days, birds were fed a conventional corn and soybean meal broiler starter, or the same diet in which major nutrients were replaced with 25, 40, or 55% ground rice hulls.

Restricted water access time as a means of growth control in turkey tom breeder candidates.

Seventeen-wk-old turkey tom breeder candidates were allowed access to water for 4 h each day, as 2 x 2-h periods, to 21 wk. After this time, water access was reduced to 1.5 h/day (21 to 25 wk) and subsequently to 1 h/day (25 to 33 wk).