The influence of dietary boron (B) supplementation on some serum parameters and egg-yolk cholesterol was studied in laying hens. A total of 224 eighteen-week-old hens of the Hyline Brown 98 strain were assigned to 7 groups with 4 replicates of 8 hens each after 10 days of adaptation, and they were fed commercial diets supplemented with 0, 5, 10, 50, 100, 200 or 400 mg/kg (diet) B (H
) for 8 weeks. Serum gamma-glutamyl transpeptidase (GGT) activity, albumin, glucose, total cholesterol, HDL- and LDL-cholesterol levels were decreased with all B levels. Except in the group receiving 5 mg/kg B supplementation, decreases were found in serum triglycerides in all groups. Serum aspartate aminotransferase (AST) activity was decreased in the groups receiving 100 mg/kg or higher levels of B. All levels of B supplementation increased lactate dehydrogenase (LDH) activity at weeks 21 and 22, while 10 mg/kg or higher levels of B increased serum globulin, urea and egg-yolk cholesterol levels. The results demonstrate that B supplementation at levels exceeding 5 mg/kg affects serum biochemical parameters and increases egg-yolk cholesterol in laying hens.
Authors:B. Sas, G. Domány, Ilse Gyimóthy, Katalin Gaál Kovácsné and M. Süth
The effect of free-range versus cage management system on corticosterone transfer into the eggs was studied in laying hens. Hungarian Yellow laying hens (age: 21 weeks, body weight: 2.0 ± 0.5 kg) were divided into two groups in the spring: Group I, free-range keeping (n = 15 layers, density: ≯ 0.5 bird/m2) in outdoor runs, with continuous access to a commercial layer feed; Group II, hens kept in battery cages (n = 17 layers, density: 2 birds/m2, natural light, continuous access to feed and water). Eggs were collected after a one-week adaptation period on days 2, 7 and 16. Corticosterone (CST) was extracted from homogenised egg samples using an ASE-200 Accelerated Solvent Extractor and then assayed by liquid chromatography linked with tandem mass spectrometry (LC-MS/MS) [Thermo Quest Surveyor high-performance liquid chromatography (HPLC) interfaced via Atmospheric Pressure Chemical Ionisation (APCI) ion source to Finnigan/Thermo Quest LCQ Deca MS/MS] using dexamethasone as internal standard with positive APCI ionisation. CST concentrations of whole eggs laid by free-range hens on days 2, 7 and 16 were 0.370 ± 0.218, 0.259 ± 0.066 and 0.915 ± 0.745 ng·g-1, respectively, while those of eggs laid by caged hens were 0.206 ± 0.157, 0.223 ± 0.165 and 0.184 ± 0.110 ng·g-1 at the above sampling times. It is concluded that in free-range laying hens the sharp changes of environmental weather conditions significantly increased the corticosterone content of eggs, while the environmentally controlled and closed battery cage management technology resulted in relatively uniform corticosterone concentrations in the whole eggs.
Authors:Željko Bukvić, Davor Kralik, Zlata Milaković, Zlata Gajčević and Marko Vukšić
, broj 1, Zagreb, veljača 1995, 17–23
Kralik, Gordana; Šperanda, Marcela; Gajčević, Zlata. 2006.:Effects of Nanofeed® preparation on egg quality and biochemical indicators in layinghens’ serum // Proceedings of XII
Authors:C. Contreras-Castillo, M. Trindade and P. Felício
The objective of this study was to characterise and compare the quality of the MSMs obtained from carcasses from breeding and laying hens to provide useful information for the processing industry. The composition of the mechanically separated meat (MSM) varied between the two groups. Laying hens contained the most crude protein (P<0.05) and high ash content (P<0.05). Calcium concentrations and bone contents were higher (P<0.05) for laying (448 mg/100 g and 1.25%, respectively) than for breeding hens (299 mg/100 g and 0.78%, respectively). Levels of unsaturated fatty acids for laying and breeding hens (75.89 and 72.82%, respectively) and cholesterol concentrations (73 and 61 mg/100 g, respectively) were higher (P<0.05) for laying hens than for breeding ones.