Bird eggs are commonly used in contaminant monitoring programs and toxicological risk assessments, but intraclutch variation and sampling methodology could influence interpretability. The authors examined the influence of egg-laying sequence on egg mercury concentrations and burdens in American avocets, black-necked stilts, and Forster's terns. The average decline in mercury concentrations betw...

COLEMAN, R. M., and WHITTALL, R. D. 1990. Variation in egg weight in the Bengalese finch (Lonchura striata var. domestica). Can. J. Zool. 68: 272-275. Variation in egg weight was examined in 29 clutches (155 eggs) from 14 pairs of captive Bengalese finches. For clutches of four and seven eggs, egg weight varied more within than among clutches. The opposite was true for clutches of five, six, an...

This experiment was conducted to measure the effects of olive leaf powder on performance, egg yield, egg quality and yolk cholesterol level of laying hens. A total of 120 Lohmann Brown laying hens of 22 weeks old were used in this experiment. The birds were fed on standard layer diets containing 0, 1%, 2%, or 3% olive leaf powder for 8 weeks. Egg weight and yield were recorded daily; feed intak...

Animal behaviors are often composed of distinct alternating behavioral states. Neuromodulatory signals are thought to be critical for establishing stable behavioral states and for orchestrating transitions between them. However, we have only a limited understanding of how neuromodulatory systems act in vivo to alter circuit performance and shape behavior. To address these questions, we have inv...

the present research was designed to examine the genetic analysis of egg weight, egg yolk weight and egg albumen weight of bovan neva black laying hens at 25, 51 and 72 weeks. for this purpose, thirty birds were selected from the layer flock in the babcock university teaching and research farm. they were individually housed in separate labeled battery cage. a total of thirty eggs were collected...

rice bran (rb) is a major by-product, produced from the rice milling process. this study was conducted to evaluate the performance, egg quality, and blood biochemical parameters of 288 hy-line laying hens fed diets with rice bran and commercial microbial phytase natuphos®5000. the experiment was a 4×2 factorial one with four rb levels (0, 5, 10, and 15%) by two phytase levels (0 and 5000 ftu/kg...

Different types (light to heavy) of laying hens are used in practice. There are questions about the optimum level of balanced protein (BP) supply in feed for different types of hens. Therefore, a broad range of amino acids intake levels [550 to 800 mg of true fecal digestible (TFD) Lys/hen per d] was tested on heavy (Lohmann Brown Classic) and light (Lohmann LSL Classic) laying hens from 24 to ...

Recently it has been recognized that reproduction itself, or the regulatory processes controlling reproduction, might contribute to physiological costs of reproduction. Reproductive anemia, a decrease in hematocrit and hemoglobin concentration, might provide one such mechanism underlying the costs of egg production in birds. In this study, we investigated the effect of repeated cycles of egg pr...

The poultry industry has an important roll to supply food production by livestock protein in developing countries including Iran. The major sections in poultry production in Iran consists of broiler and laying production, broiler and laying breeder production, hatchery and line breeder production. Commercial productions in Iran have changed more or less during 1999-2003. The number of farms for...