2. In 4 consecutive trials, 4752 hens were recorded for keel bone status. Evaluation of plumage condition was made for 1440 hens and bone breaking strength was recorded for 1200 hens. A total of 4962 eggs were analysed for internal and external egg quality traits. Analyses involved 30 small group compartments per trial.
3. The layer line had a much more pronounced influence on humerus breaking strength than on tibia breaking strength.
4. Plumage condition, particularly on the neck, was positively correlated with humerus breaking strength in both layer lines.
5. An average of 34% of LB and 23% of LSL hens showed keel bone deformities, with higher proportions of slight deformities.
6. Slight keel bone deformities, rather than moderate to severe, increased significantly during the laying period.
7. Stocking density had no influence on bone breaking strength, keel bone status and egg quality traits.
8. LB layers had a 1.4-fold higher humerus, but only a 1.06-fold higher tibia breaking strength compared to LSL layers.
9. Tibia breaking strength was significantly affected by the interaction of group size and layer line. LSL layers in small groups had lower tibia breaking strengths than those of the large groups. 相似文献
2. In the experiment, 1800 44-week-old Hy-line brown laying hens were divided into 5 groups with 6 replicates per group and 60 hens per replicate. The experiment lasted for 12 weeks. The layers in the control group (control) were given a basal diet with 0.36% non-phytate P (NPP), while the treatment groups received diets containing 360 U of exogenous phytase/kg with 0.26% NPP (EP) or 360 phytase U of PTC/kg diet with 0.26% (PTC1), 0.21% (PTC2) or 0.16% (PTC3) NPP.
3. The results showed that there was no significant difference in egg production, average daily feed intake, feed efficiency, rate of broken or soft-shell egg production or egg mass among the treatments. There was no significant difference in eggshell thickness or eggshell strength. On the other hand, no differences in any of the bone variables were found between treatments. The faecal P percentage content in EP, PTC1, PTC2 and PTC3 groups was significantly lower than the control group.
4. In summary, the PTC could be used in the feed of laying hens instead of EP to reduce P excretion without effecting production and bone mineralisation. 相似文献
2. In Experiment 1, nest‐site selection by members of a group of light hybrids was studied in a complex pen‐system. Eggs were clumped in distribution ; only one individual laid in the most secluded part of the system.
3. Experiment 2 provided light hybrids with an extensive outdoor area, but similarly clumped laying was observed; there was no indication that hens attempted to find concealment for nesting.
4. In Experiment 3, hens from a group of light hybrids just coming into lay and from a group of mature medium hybrids were tested singly, in an area that included a cage containing some of their flockmates. Most subjects from both groups laid near the other birds rather than in isolation.
5. In semi‐intensive conditions, the majority of hens are apparently gregarious rather than solitary in their nesting behaviour. 相似文献
2. After a 4-d period of acclimatisation, hens were individually housed and provided with ad libitum food and water for a 24-h period. The number of eggs laid, egg weight, feed and water consumption during this period were recorded. Keel bone strength was also assessed.
3. Hens free from keel fractures laid more eggs (91.7% vs. 84.9%) of significantly heavier weight (61.9 g vs. 60.2 g), ate less feed (139 g vs. 151 g) and drank less water (212 ml vs. 237 ml) than hens with fractures.
4. There was a significant positive association between keel fracture severity and water consumption, and a significant negative association between keel fracture severity and egg weight and keel bone strength.
5. This small-scale study on individual birds shows that keel bone fractures may have an impact on the economics of egg production. 相似文献
2. Supplementation with hesperidin did not affect egg production, egg weight and egg quality traits.
3. No hesperidin effect on yolk and plasma cholesterol was observed. A strain effect was found with lower total and per g yolk cholesterol of brown hens in comparison to the white ones.
4. Oxidative stability of egg yolk, expressed as ng MDA/g yolk, was significantly improved in the hesperidin groups even from the first week of supplementation. At the same time, a significant improvement in the oxidative stability of egg yolk due to the incorporation of hesperidin in hens’ diet was observed after 30 and 90 d of storage at 20°C and 4°C, respectively.
5. No hesperidin by strain interaction was detected for any of the traits measured.
6. In conclusion, incorporation of hesperidin to laying hens’ feed did not affect productive and egg qualitative traits. On the other hand, dietary hesperidin supplementation significantly improved oxidative stability of both fresh and stored eggs. Antioxidant properties of hesperidin seem to make it a promising natural agent for improving the shelf life of eggs. 相似文献
2. During the 12-week experimental period, a total of 72 laying hens aged 52 weeks were randomly distributed among 6 experimental groups. Each experimental group contained 4 replicates, each with three birds. The experiment was a randomised design consisting of a 3 × 2 factorial arrangement, with three levels of wheat substitution and two levels of enzyme (xylanase: 1500.00 U/kg, β-glucanase: 100 000 U/kg, cellulase: 1 000 000 U/kg, α-amylase: 160 000 U/kg) inclusion in the diet. Wheat replaced 0, 50, or 100% of maize with or without 1.0 g/kg enzyme supplementation in iso-nitrogenous and iso-caloric experimental diets.
3. Body weight, egg production, egg weight, egg mass, eggshell thickness, and the feed conversion ratio were adversely affected by the wheat-based diet. The eggshell quality parameters decreased with enzyme supplementation to the diet.
4. Wheat-based diets adversely affected calcium and phosphorus concentrations in the tibia, but the addition of the enzymes to the wheat-based diet prevented the negative effects of wheat-based diets on tibia mineralisation in laying hens. The wheat-based diets tended to reduce plasma mineral contents, and the addition of enzymes tended to affect plasma minerals and biomechanical properties of the tibia positively in laying hens.
5. These results indicate that wheat-based diets in aged laying hens adversely affected the mineral metabolism compared with maize-based diets, and the negative effects of wheat on bone mineralisation can be prevented by enzyme supplementation to the diets in laying hens. 相似文献
2. A total of 360 Beijing PINK-1 laying hens (60 weeks old) were randomly distributed among five dietary treatments, each of which included 6 replicates of 12 hens. Dietary treatments were basal diet supplemented with 0 (control), 0.5, 1.0, 2.0 and 4.0 g/kg diet resveratrol. The study lasted for 9 weeks including 1 week of adaptation and 8 weeks of the main experimental period.
3. The results indicated that dietary resveratrol significantly improved feed conversion ratios during 5–8 weeks and 1–8 weeks of the trial. Increasing dietary concentrations of the resveratrol linearly improved Haugh unit and albumen height of eggs.
4. The content of total cholesterol (TC), total triglyceride (TG), low density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C) in serum and cholesterol in yolk was significantly decreased by dietary resveratrol, and there were significant linear correlations between these indexes and resveratrol supplemental levels.
5. Dietary resveratrol supplementation significantly improved serum Glutathione peroxidase (GSH-Px) enzyme activity and decreased serum malondialdehyde (MDA) content in groups with 2.0 and 4.0 g/kg resveratrol as compared to the control, respectively. However, supplementation of resveratrol did not affect the activity of serum superoxide dismutase (SOD).
6. It is concluded that resveratrol supplementation has a positive effect on performance, lipid-related traits and antioxidant activity of laying hens. 相似文献
2. Egg weight was poor with the low fat basal diet but increased in relation to the amounts of maize oil (4 and 30 g/kg) included in the diet.
3. With a diet containing 30 g olive oil/kg, egg weight was similar to that obtained with the diet containing the same amount of maize oil.
4. Rearing the birds on diets containing low or moderate amounts of linoleic acid did not affect the response to fatty acid content of the layer's diet.
5. It is concluded that the requirement of the laying hen for linoleic add is not higher than 9 g/kg but that egg weight does respond to higher dietary amounts of readily absorbable fatty acids. 相似文献
2. In this study, we investigated the effects of quercetin on laying rate, egg quality and blood traits associated with egg quality in laying hens (Hessain) during the late laying period and explored the possibility of using quercetin as a functional feed additive.
3. The laying hens (n = 240; 39 weeks old) were randomly assigned to 4 treatments consisting of 6 replicates (n = 10) and were fed with diets containing quercetin at 0, 0.2, 0.4 or 0.6 g/kg.
4. Results showed that laying rate was increased and feed–egg ratio was decreased significantly by 0.2 and 0.4 g/kg quercetin. Compared with controls, Haugh unit, eggshell strength, eggshell thickness and yolk protein were increased, but yolk cholesterol was decreased by quercetin.
5. In conclusion, quercetin was beneficial in improving performance and egg quality. The recommended concentration of quercetin is 0.4 g/kg of the basal diet. At this concentration, increased laying rate, improved egg quality and reduced yolk cholesterol can be expected. 相似文献
2. The taint was due to the inclusion of either 25 or 70 g Icelandic capelin fishmeal/kg of the diet.
3. Babcock hens produced significantly more (17%) tainted eggs than Warrens (1.2%).
4. Tainted eggs were significantly reduced to a very low proportion (1.3%) by the third day of feeding a fishmeal‐free diet.
5. The taint was due to the presence of up to 17 mg/trimethylamine kg in affected eggs. 相似文献
2. One-d-old commercial Arbor Acres broilers were fed with a maize–soya bean basal diet for 42 d, supplemented with oils according to the following 5 treatments: lard (lard group); linseed oil (linseed oil group); palm oil (palm oil group); linseed oil + palm oil (60:40 or 40:60 w/w, LP-1 group and LP-2 group, respectively).
3. No significant differences in weight gain, feed intake and gain/feed ratio were observed between the lard and linseed oil groups. Birds fed on palm oil had significantly greater weight gain and feed intake than those fed on lard or linseed oil. Growth performance in LP-1 and LP-2 was significantly greater than that of single-oil groups.
4. Tibia growth and bone characteristics were not influenced by supplementation with lard, linseed oil, or palm oil alone, but broilers fed on a mixture of fats had significantly greater tibia weight and length compared to broilers fed on linseed oil. Bone mineral density in tibia was significantly increased in LP-1 and LP-2 groups.
5. Supplementation of linseed oil alone or in combination with palm oil enhanced apparent digestibility of calcium, reduced serum calcium and increased tibia calcium concentrations. Moreover, supplementation with linseed oil alone or in combination with palm oil had a positive effect on biomarkers of bone growth.
6. The combination of linseed and palm oils was beneficial for growth performance, tibia growth and biomarkers of bone metabolism. 相似文献
2. The intake of low‐calcium diet and of oyster shell were similar for each light period of each lighting regimen.
3. Ovipositions were distributed virtually at random throughout the day and the mean interval between successive eggs within a clutch was increased.
4. Reducing the total daily photoperiod from 12 to 6 h decreased daily food consumption. 相似文献
2. This study aimed to investigate the effect of dietary BP on laying performance, egg quality and caecal bacterial populations in laying hens.
3. The dietary BP used in this experiment was a mixture of individual BP targeting Salmonella gallinarum, Salmonella pullorum, Salmonella typhimurium, Salmonella enteritidis, Salmonella derby and Staphylococcus aureus.
4. A total of 360 Hy-Line Brown laying hens of 32 weeks of age were allotted to one of three dietary treatments with 6 replicates in a completely randomised design. The basal diet was prepared, and 0.4 or 0.8 g/kg BP mixture was supplemented to the basal diet. Diets were fed to hens for 8 weeks.
5. Laying performance and egg quality were not affected by dietary treatments. As inclusion levels of BP mixture in diets were increased, the DNA copy numbers for Salmonella spp. in the caecal contents decreased linearly, whereas the DNA copy numbers for Escherichia coli in the caecal contents increased linearly.
6. Results indicate that dietary supplementation of BP mixture decreases the target Salmonella spp. populations but increases Escherichia coli populations in the gastrointestinal tract of laying hens with little impact on laying performance and egg quality. 相似文献
2. The CT image acquisition was performed on 54 healthy TETRA SL genotype laying hens at 90 weeks of age as well as in the 69th week of the egg production period in vivo and their tibiotarsal bones, ex vivo.
3. Breaking strengths and ash content of the tibiotarsal bones were estimated based on the calculated mineral density of skeletal and tibiotarsal bones by means of CT with an estimation accuracy R2 0.963 and 0.975, respectively.
4. In conclusion, the current investigation demonstrated that the acquisition protocol of CT for total-body composition analysis has a good potential for measuring the mineral status and breaking strength of the reference bone in laying hen. 相似文献
2. Over two experiments, 9 or 10 hens of each of three layer lines (Lohmann Selected Leghorn (LSL), Lohmann Tradition (LT) and Lohmann Brown (LB)) were filmed while landing on three different perch types, including steel perches of various diameters, a commercial mushroom-shaped plastic perch and a newly developed prototype perch with a soft surface material.
3. Data on landing behaviour (safe vs. unsafe or failed landing) following downward jumps were collected for 25, 50 and 60 cm vertical distances and 75 cm horizontal distance between a wooden start perch and the different destination perches.
4. The highest proportion of safe landings occurred on the prototype perch, whereas least safe landings were observed on steel perches, irrespective of their diameter. The mushroom-shaped perch was intermediate with regard to the safeness of landing.
5. A threshold of 50 cm vertical distance (34° slope) was identified as the optimum for downward jumps on perches in order to reduce the risk of unsafe or failed landings. Above this threshold, the proportion of safe landings declined significantly.
6. Brown shell layer types (LB and LT) had a lower proportion of safe landings compared to the white shell layer type (LSL), whereas no difference was found between LB and LT layer lines.
7. Although steel perches prevail in commercial housing, these perches were found to be least advantageous with regard to landing behaviour. The prototype perch provided the most stable footing on perching and is a promising alternative to replace commercial steel perches, thus helping to reduce the risk of perch-related keel bone injury. 相似文献
2. Three layer hybrids (two brown and one white, ISA-Hendrix Genetics, France) and two substrate conditions (with or without wheat bran automatically distributed on the PSA) were compared in a 3 × 2 experimental design with 12 cages per treatment.
3. Substrate distribution improved laying rate with no impact on the frequency of dirty or cracked eggs.
4. Substrate distribution improved the viability and body integrity of hens, which were not beak-trimmed.
5. Distribution of substrate tended to increase the number of hens in the PSA and enhanced their pecking and scratching behaviours but had a negative impact on the number of dust bath bouts per cage and encouraged dust bathing on the wire floor close to the feeder.
6. The white hens laid more eggs in the nest than the brown birds and used the PSA more for pecking, scratching and dust bathing at the end of the day than the brown hens, underlining the necessity to adapt cage furnishing and rearing management to specific behaviours of each layer genotype. 相似文献
2. In both groups the water intake and water loss at all temperatures were well balanced.
3. Water to food ratios and water content of excreta of normal hens increased with increasing temperature.
4. The wetter excreta at 35 °C are caused by an increased urine production and not by an increased water passage through the alimentary tract. 相似文献
2. The birds were fed on either maize- or wheat-based diets during rearing and production and on a fast- or slow-feed allocation programme from 14 to 29 weeks of age. At 22 weeks, 69 females from each pen were placed in a layer house where feeder space (FS) either remained similar or was increased.
3. Eggs produced at 33 weeks were incubated, eggshell conductance (G) was determined and a sample of 14 chicks from each treatment combination was taken to obtain bone traits at hatching.
4. Diet type did not influence G, yolk-free body weight (BW), residual yolk weight or relative asymmetry (RA) of any bilateral traits of leg bones of hatchlings. However, breeder diet type was involved on two-way and three-way interaction effects on progeny leg bone traits.
5. Breeders feed restricted according to the slow-feeding programme laid eggs with greater G compared to those managed with the fast-feeding programme, but there was no effect of feeding programme on progeny bone traits at hatching.
6. Eggs from breeders given more FS at photostimulation had greater G than those from breeders provided with similar FS. Maternal FS change did not influence hatchling yolk-free BW; however, breeders given more FS produced progeny with heavier tibias and shanks and longer femurs compared with those provided with similar FS, but only when breeders were fed on maize. Moreover, increased maternal FS at photostimulation was associated with an increased RA of femur length in the progeny.
7. It was concluded that breeder FS change at photostimulation influenced eggshell conductance and consistently affected bone development of the broiler progeny. 相似文献
2. The data contain information about the laying performance of 1831 individuals in the first year of laying. To describe the trajectory of the laying performance, 10 mathematical models were tested. For the genetic parameter estimation of egg production, data from 1038 birds were used with a production higher than 20 eggs during the first season of laying.
3. The analysis of egg production was based on single and multi-trait models. Heritability, genetic and phenotypic correlations between phases of the laying performance as well as breeding values were estimated.
4. The best adaptation to the goose egg laying curve was the Ali and Schaeffer model. The estimates of heritability were 0.20 (0.06 SE) using the single-trait model and ranged from 0.12 to 0.24 using the multi-trait model.
5. The results suggest that the BLUP method can support the conservation programme. 相似文献
2. Lauryl sulphate at 2.5 g/kg or more in the diet significantly increased shell breaking strength, shell thickness and shell weight at 24 and 36 weeks. In 48‐week‐old hens only shell breaking strength was increased significantly. Egg production and egg weight were not affected significantly by lauryl sulphate.
3. Lauryl sulphate might increase these measures of quality by increasing shell deposition and/or shell elasticity. 相似文献