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Laying Hens (laying + hen)
Selected AbstractsA pilot study into the chemical and sensorial effect of thyme and pennyroyal essential oil on hens eggsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 9 2009Tegan J. Smith Summary Previously, it has been shown that thyme and pennyroyal essential oils have potential as acaricides against the poultry red mite Dermanyssus gallinae. The effect of these oils on the occurrence of taint in hens' eggs was investigated using in vitro immersion tests and in vivo methods where poultry huts containing laying hens were sprayed weekly with oil. Analysis of extracts from eggs by gas chromatography mass spectrometry (GCMS) showed that no detectable taint was present in hens' eggs. However, consumer sniff tests, although restricted and only preliminary in nature, showed a significant negative response to the smell of both unbroken and cracked open eggs between those taken from poultry huts treated with pennyroyal essential oil and all other eggs tested. Some essential oils, such as thyme, may be more suitable as an acaracidal product than others, such as pennyroyal, for the use within a commercial poultry system for laying hens. [source] Sand intake by laying hens and its effect on egg production parametersJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 4 2008J. Van Der Meulen Summary Soil intake may be the most prominent source of environmental contaminants for free range and organic hens, but there are no quantitative data concerning soil intake by domestic hens. Consumption of soil of 14,32 g a day can be estimated from literature, but such a dilution of nutrient intake seems incompatible with high productivity. In this study laying hens were fed pelleted diets with 0%, 10%, 20%, 25% and 30% of sand addition to determine its effect on productivity. Feed intake, feed and nutrient (feed minus sand) conversion ratio, egg production, egg weight and body weight gain were measured over a 4-week period. Acid insoluble ash concentration in the faeces was measured to determine the accuracy of estimating the soil ingestion by the soil-ingestion equation for wildlife as a way to determine soil ingestion of free range and organic hens under practical circumstances. The hens were able to compensate the dilution of the diet with 20%, 25% and 30% of sand by increasing their feed intake. Feed intake increased significantly and feed to egg conversion ratio decreased significantly with increasing sand levels in the diet. The nutrient to egg conversion ratio of the diet without sand tended to be worse than for the diets with sand, presumably due to the total absence of coarse material in the diet. There were no differences in egg production and egg weight between hens fed the different diets but body weight gain was significantly lower for the hens fed the diets with 20%, 25% and 30% of sand. Estimation of sand ingestion was done by the soil-ingestion equation for wildlife. Provided that the actual dry matter digestibility coefficient of the nutrient part of the diet is taken into account, estimating the soil ingestion according to the soil-ingestion equation for wildlife seems an appropriate way to determine soil ingestion for free range and organic hens under practical circumstances. [source] Effects of dietary black cumin seed (Nigella sativa L.) on performance, egg traits, egg cholesterol content and egg yolk fatty acid composition in laying hensJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2009Professor Dr Sakine Yalç Abstract BACKGROUND: The objective of this study was to determine the effects of dietary black cumin seed on performance, egg traits, egg cholesterol content and egg yolk fatty acid composition in laying hens during a 12 week period. For this purpose a total of 160 Lohmann Brown laying hens 36 weeks of age were allocated to four dietary treatments with one control group and three treatment groups. Black cumin seed (Nigella sativa L.) was used at the level of 5, 10 and 15 g kg,1 in the diets of the first, second and third treatment groups, respectively. RESULTS: Dietary treatments did not significantly affect body weight, feed intake, egg production, egg quality characteristics and blood parameters. Diets containing 10 and 15 g kg,1 black cumin seed increased egg weight (P < 0.01), improved feed efficiency (P < 0.01) and decreased egg yolk cholesterol, saturated fatty acids (% of total fatty acid methyl esters) and the ratio of saturated to unsaturated fatty acids (P < 0.05) compared to the diet of control group. CONCLUSION: Dietary black cumin seed at the level of 10 and 15 g kg,1 had beneficial effects on egg weight, feed efficiency, egg cholesterol content and egg yolk fatty acid composition. Therefore it can be used at the level of 10 and 15 g kg,1 in the diets of laying hens. Copyright © 2009 Society of Chemical Industry [source] The influence of different single dietary sources on moult induction in laying hensJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2007Behzad Mansoori Abstract An investigation was carried out to assess the possibility of using single dietary sources as alternatives to feed deprivation for the induction of moult in commercial laying hens. The study involved six dietary groups of 29 laying hens: unmoulted, dried tomato pomace, alfalfa meal, rice bran, cumin seed meal and feed withdrawal. The birds received the above diets during the moulting period (11 days), and body weight loss and ovary weight regression were measured. Post-moult production parameters (number of eggs produced per hen per day, egg weight, shell weight, yolk colour and Haugh unit) were measured for 12 weeks. Results showed that all dietary sources were as effective as feed withdrawal in causing ovary weight regression in birds. Birds provided with tomato pomace or alfalfa showed lower weight losses than feed-deprived birds at the end of the moulting period. Hens moulted by tomato pomace or alfalfa exhibited post-moult levels of egg production over a 12 week period that were superior to those of hens moulted by feed withdrawal. Post-moult eggs laid by hens moulted by all dietary sources were of comparable quality to eggs from feed-deprived hens and superior to those from unmoulted hens. As fibrous feeds with low metabolisable energy and an appreciable amount of protein, dried tomato pomace and alfalfa meal may be fed to hens on an ad libitum basis for effective moult induction while reducing the stress of severe starvation and retaining comparable egg quality and production. Copyright © 2007 Society of Chemical Industry [source] Dose,response feeding study of short chain chlorinated paraffins (SCCPs) in laying hens: Effects on laying performance and tissue distribution, accumulation and elimination kineticsMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 2 2007Karl-Heinz Ueberschär Abstract Technical short chain chlorinated paraffins (C10,C13 with 60% chlorine) were fed to 93 laying hens from 24 to 32 weeks of age in increasing concentrations of up to 100 mg/kg feed. No significant influence on health, relative organ weights or performance (laying intensity, egg weight, feed consumption) was noted. The chlorinated paraffin content of the tissues was linearly related to the concentration of short chain paraffins of the feed. The highest concentrations were found in abdominal fat, egg yolk and fatty tissues. Breast muscle, egg albumen and bile fluid contained minimal or no residues. Less than 1% of the chlorinated paraffins ingested were incorporated into the body (without head, feet, gut and feathers), whereas about 1.5% were eliminated with the egg yolk and 30% were excreted with urine and faeces. A six-week kinetic depuration study revealed a biphasic elimination with half-lifes of 4,40 min (liver, kidneys, legs, fat, blood) for the initial rapid phase, and 15,30 days (blood, fat, liver, yolk, kidneys, legs) for the terminal slow phase. [source] Substrate oxidation and retention in pigs and poultryANIMAL SCIENCE JOURNAL, Issue 2 2002André CHWALIBOG ABSTRACT A model combining data from gas exchange measurements with nutrient balances, demonstrating energy transfer between the pools of protein, carbohydrate and fat and their partition in the body, is described. Data from energy metabolism experiments with growing pigs and laying hens is incorporated into the model in order to illustrate methods of calculations and interpretations of the model. The experiments with pigs were carried out with growing pigs (20,100 kg) measured alternately on high (ad libitum) and low (near maintenance) feed levels on diets with low or high fat concentration. When energy intake from digested carbohydrate covered the requirements for growth, heat from oxidation of carbohydrate contributed 85,90% to the total heat production, while there was no net oxidation of fat. When the intake of digested carbohydrate was not sufficient to cover requirements, fat was mobilized from the body and oxidized. Energy from oxidation of carbohydrate was in all measurements below the energy in the carbohydrate pool, indicating transfer of energy from carbohydrate to fat metabolism in the process of de novo lipogeneis. The experiments with hens were carried out with 62 hens during the laying period from 26 to 47 weeks of age. The hens originated from two strains (A and B); they were kept in battery cages either individually or 3 hens/cage and fed ad libitum with an identical commercial diet. The partition of the protein pool between oxidation and retention was not influenced by the housing system. However, the genetic origin of hens effected protein utilization with relatively lower oxidation and higher retention in Strain B. The main part of the carbohydrate pool was oxidized (45,60%), but the hens kept individually oxidized more carbohydrate than those kept 3 hens/cage. Further, there were significant differences between the strains. Generally, about half of the fat pool originated from de novo lipogenesis from carbohydrate, indicating the importance of this process for fat retention in eggs. Fat oxidation depended on the energy supply from carbohydrate, hence with higher use of carbohydrate for oxidation in Strain B less fat was oxidized and more was used for fat synthesis. The presented results indicate that by combining results from gas exchange measurements with nitrogen and energy balances it is possible to evaluate the contribution of nutrients to the oxidative processes and the energy transfer between substrate pools. [source] | |||||||||||||