نتایج جستجو برای: eggshell quality
تعداد نتایج: 754832 فیلتر نتایج به سال:
Owing to exceptional biomolecule preservation, fossil avian eggshell has been used extensively in geochronology and palaeodietary studies. Here, we show, to our knowledge, for the first time that fossil eggshell is a previously unrecognized source of ancient DNA (aDNA). We describe the successful isolation and amplification of DNA from fossil eggshell up to 19 ka old. aDNA was successfully char...
Shell color is not an indication of internal egg quality and says nothing about the nutritive value or the quality of the egg (Flock et al., 2007). However, many consumers who prefer brown eggs, also pay attention to intensity and uniformity of color, and pale or unevenly colored eggs may be rejected. Clearly, reduced variability of eggshell color improves the presentation of eggs at point of s...
The first clutch of Mesozoic eggs containing embryos was collected more than twenty years ago from the Rooidraai locality in Golden Gate Highlands Park, South Africa. The Elliot Formation crops out throughout the area, and although the sediments exposed at Rooidraai were once thought to be Late Triassic in age, they are now regarded as Early Jurassic. The Elliot Formation preserves a rich terre...
An experiment was conducted to investigate the effects of environmental temperature and dietary Mn on egg production performance, egg quality, and some plasma biochemical traits of broiler breeders. A completely randomized factorial design involved 2 environmental temperatures (a normal temperature, 21 ± 1°C, and a high temperature, 32 ± 1°C) × 3 dietary Mn treatments (a Mn-unsupplemented corn–...
The eggshell is an important physiological structure for the embryo. It enables gas exchange, physical protection and is a calcium reserve. Most squamates (lizards, snakes, worm lizards) lay parchment-shelled eggs, whereas only some gekkotan species, a subgroup of lizards, have strongly calcified eggshells. In viviparous (live-bearing) squamates the eggshell is reduced or completely missing (he...
Laser-Raman and infrared spectroscopic studies reveal abundant beta-pleated sheet conformation in the eggshell proteins of the fish Salmo gairdneri. This secondary structure is the underlying molecular conformation, dictating the formation of the helicoidal architecture of the eggshell. Disulphide bonds crosslink the eggshell proteins of the fertilized eggs and are apparently found in g-g-g (ga...
Physiological constraints on colouration have been widely reported; especially in birds, which trade-off antioxidant responses against colourful costly signals. One female extended phenotypic trait, which might also highlight important physiological trade-offs, is the pigmentation of their eggshells. In ground-nesting species, producing eggs that are visually undetectable by predators is the be...
Meat and bone meal (MBM) and oyster shell meal (OSM) were supplemented to a basal diet (LMS), either alone or in combination, in order to assess the dietary influences of those complementary Ca sources on performance and egg quality of laying hens. Four hundred and thirty-two Brown-Nick hens, at the beginning of their second production period, were divided into four treatment groups with six re...
This experiment was designed to evaluate the effects of different sources of calcium at different rates and cholecalciferol(Vitamin D3) on the performance and egg quality of Hy-line W-36 Laying hens. In this study a total of 648 hens were managed in a completely randomized design using a factorial arrangement of 3 × 3 × 2 treatments, with three calcium sources (oyster shell, OS; ground limeston...
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