The effects of housing systems on the calcium requirement for eggshell production, eggshell quality and on the breaking strength of the hen’s tibia were evaluated. Unenriched cages (UN) (24 laying hens), enriched cages (EN) (16 laying hens) and floor system (FS) (24 laying hens) were used in this experiment. The eggshell production of laying hens from 19 to 66 weeks of age was higher (P < 0.01)...

Improvements in the duration of fertility (DF) could increase the interval between successive artificial inseminations, thereby decreasing the cost associated with production of hatching eggs. The molecular mechanisms involved in DF in hens remains under-explored. In this study, expression levels of the transforming growth factor-β genes (TGFβs: TGFβ1, TGFβ2, TGFβ3) were investigated in utero-v...

Selection of a line of White Leghorn chickens for high group productivity and longevity resulted in reducing cannibalism and flightiness in multiple-hen cages. Improvements in survival might have been due to changes of physiological homeostasis. The objective of the present study was to test the hypothesis that genetic selection for high (HGPS) and low (LGPS) group productivity and survivabilit...

An experiment was conducted to evaluate the effects of either a low-fat (8% of total calories) or high-fat (47% of total calories) diet on Large White breeder females maintained at a constant (21 C) or a cyclic temperature regimen (12 to 27 C). Each diet was fed to 32 hens individually caged in the cyclic condition and 46 in the constant condition. Energy consumption, reproductive performance, ...

The objective of this study was to compare the nutritional performance of laying hens fed maize grain from event DP-Ø9814Ø-6 (98140; gat4621 and zm-hra genes) and processed soybean meal from soybeans containing event DP-356Ø43-5 (356043; gat4601 and gm-hra genes), individually or in combination, with the performance of hens fed diets containing nontransgenic maize and soybean meal. Healthy pull...

Molting is a common practice used by the commercial egg industry to rejuvenate flocks for a second or third laying cycle. During this time the hens rest from production, and the reproductive organs are rejuvenated to increase production and quality during the next laying cycle. Although feed withdrawal (FW) is the most popular and effective method of molt induction, it has come under scrutiny d...

Incubation behavior or broodiness in turkey hens is characterized by ovarian regression, hyperprolactinemia, and persistent nesting. Nest-deprivation of incubating turkey hens results in disruption of broodiness accompanied by a precipitous decline in plasma prolactin (PRL) concentrations. The objective of the present study is to examine cellular changes in the pituitary gland associated with n...

Expression of peroxisome proliferator-activated receptor-alpha (PPARalpha) has been shown in liver of chicks, but effects of its activation have not yet been investigated. In this study, laying hens were treated with clofibrate, a synthetic PPARalpha agonist, to investigate the effects of PPARalpha activation on liver lipid metabolism. Hens receiving a diet containing 5 g of clofibrate/kg had a...

The aim of this study was to compare the effects of a new organic Se [2-hydroxy-4-methylselenobutanoic acid (HMSeBA)] with routinely used mineral and organic Se sources (sodium selenite and selenized yeast) on chosen performance criteria and Se deposition in egg and muscle of laying hens. A total of 240 laying hens (40 wk of age) were randomly assigned to 6 treatments for 56 d with 8 replicates...

S OF PAPERS 229 72 Effects of feeding various digestible lysine intake levels by Cobb 500 broiler breeder hens on reproductive performance. L. Mejia*SC, C. D. McDaniel, and A. Corzo, Mississippi State University, Mississippi State. A study was conducted to examine the reproductive parameters of Cobb 500 broiler breeder hens fed different daily consumption levels of dig lysine (mg/hen/day) on th...