How molting of laying hens influences body composition and blood parameters.

The physiological and metabolic changes laying hens undergo during molt are poorly understood, but could aid in understanding why hens stop egg production during the first cycle of lay. We therefore induced a molt and studied how this influenced body composition, blood parameters and production performance. Additionally, four diets postmolt were fed in a 2 × 2 factorial design with two levels of metabolisable energy lay (ME Lay; low = 11.

Effects of metabolizable energy intake and body weight restriction on layer pullets: 2 - Body composition and onset of lay.

This study aimed to determine the effects of dietary ME and BW restriction on layer pullet sexual maturation, carcass composition and reproductive organs. Two trials were conducted: a precision feeding (PF) (Experiment 1) and a conventional (CON) experiment (Experiment 2). Experiment 1 was a 2 × 4 factorial arrangement with two feed allocation (FA) levels: meal every visit (MEV) or restricted to the lower limit of Lohmann Brown-Lite recommended BW; and three dietary ME levels: Low, Standard (Std), and High (2,600, 2,800, and 3,000 kcal/kg, respectively); the fourth treatment enabled birds to choose from the three diets (Choice).

Gastrointestinal tract morphology, nutrient digestibility, and digesta mean retention time in laying hens of two different breeds fed with fine or coarse oat hulls.

The inclusion of fiber-rich ingredients in poultry diets is expected to increase due to societal-, ecologic-, and economic developments. Particle size of dietary fiber sources, such as oat hulls (OH), has been shown to play a key-role in nutrient digestibility and digestion process, but the response may depend on the genetic background of the bird. This study aimed to test the hypothesis that laying hens varying in genetic background respond differently to the particle size of OH regarding gastrointestinal tract development, apparent ileal (AID) and total tract digestibility (ATTD), and digesta mean retention time (MRT).

Linear and nonlinear models for assessing carcass composition using dual X-ray absorptiometry in egg- and meat-type chickens.

The objective of this study was to develop appropriate correction equations for dual energy X-ray absorptiometry (DXA) for total carcass composition of live meat- and egg-type chickens. Linear (bivariate linear and multivariate linear) and nonlinear (polynomial, multivariate polynomial, broken-line and Gompertz) equations were used to estimate carcass composition of DXA-scanned birds based on chemical proximate analysis. A total of 288 laying females (10-30 wk of age) and 305 broiler breeder females (4-32 wk of age) were used.

The influence of breed, dietary energy and lysine on laying persistency and body composition of laying hens.

The effect of dietary energy and lysine levels on laying persistency and body composition in brown and white hens was studied. Dietary treatments with 2 Metabolizable Energy levels (ME lay; constant or reduction over time) and 2 apparent fecal digestible Lys levels (AFD Lys; constant or reduction over time), were fed to Lohmann white or brown hens, from 17 to 75 wk of age, in a 2 × 2 × 2 factorial design. Data were subjected to mixed model analyses.