Quality characteristics of quail eggs

1. An experiment was carried out with laying Japanese quail to study the influence of age on their egg quality.

2. Egg, yolk, albumen and shell plus membrane weights increased, whereas the egg shape, specific gravity and shell thickness decreased between 49 and 154 days of age.

3. Yolk, albumen and shell plus membrane comprised 32–59%, 53–57% and 7–80%, respectively of the total egg weight.

4. Regression between the quail's age and the characteristics of eggs were derived and correlation coefficients ranged from —0–42 to — 0–86. The albumen weight was more highly correlated with egg weight than yolk weight.

5. Relationships were also derived between egg shape and specific gravity, and egg shape and albumen weight.

6. It was concluded that the eggs’ characteristics were modified as the quails aged, and the best criterion of the shell's strength was the egg shape.     

Selection for high specific gravity of eggs in a flock of Australorp hens

1. A realised heritability of 0.23 was obtained in an Australorp flock (S) selected for five generations for high egg specific gravity.

2. A comparison with an unselected control flock (C) over 50 weeks of lay in the final generation indicated a number of statistically significant correlated responses in commercially important traits in the S line in addition to the direct response of + 0.004 in specific gravity.

3. With an increase in specific gravity, there was a decrease of 3.4 in the percentage of soft‐shelled eggs laid.

4. The weight and albumen height of eggs measured within 1 hour of lay declined by 1.8 g and 2.1 Haugh units respectively.

5. There were reductions in the weight and albumen height losses of eggs stored over a 10‐d period (C 0.74, S 0.62 g and C 17.9, S 15.0 Haugh units respectively), so that at the end of this period the albumen heights in both lines were the same.

6. Average body weight and daily food intake were less by 0.28 kg and 7.5 g respectively.

7. Although there was no change in egg production, the average age at first egg was reduced by 11.3 d.     

Differences in egg‐shell quality among the Sinai Bedouin fowl,the commercial white leghorn and their crossbreds

1. A comparison of egg‐shell characteristics was made among the Sinai breed (a desert inhabiting strain), the commercial White Leghorn and their reciprocal crossbreds.

2. The Sinai egg was smaller and its shell thicker and stronger than the Leghorn egg. All the differences were statistically significant.

3. Shell thickness and strength of Leghorn eggs were in accordance with values predicted on the basis of egg mass, while those of the Sinai and the two crosses were considerably higher than predicted.

4. The apparent differences in mean egg mass between Sinai and Leghorn breeds did not explain the differences in egg‐shell quality, neither did the shape index which was very similar among all breeds.

5. The findings suggest that the differences in egg‐shell properties are of a genetic origin.

6. The thick, strong and less permeable egg‐shell of the Sinai breed may reflect adaptations to its arid environmental origin and to incubation in the open.

7. These genetically‐determined egg‐shell characteristics might serve in a future selection for improved egg‐shell quality in poultry.     

Evaluation of bone strength,keel bone status,plumage condition and egg quality of two layer lines kept in small group housing systems

1. The aim of the present study was to determine the influence of large (54 or 60) and small (36 or 40) group sizes and tiers of the small group housing system “Eurovent German” on tibia and humerus bone breaking strength, keel bone status, plumage condition and egg quality for two commercial layer lines, Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB), at the same stocking density (890 or 830 cm²/bird).

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.     

Egg‐shell water Vapour conductance of the domestic fowl: Comparison between two breeds and their crosses

1. A comparison of egg water loss and egg‐shell water vapour conductance was made between the Sinai fowl (a desert inhabiting breed) and the commercial White Leghorn, together with their reciprocal crossbreds.

2. The Sinai egg was found to be smaller and less permeable to water vapour than the eggs of the Leghorn and crossbreds. The differences were statistically significant.

3. The measured egg‐shell water vapour conductance of the Sinai breed was 25% lower than predicted on the basis of egg mass.

4. The low permeability of the Sinai egg shell might be related to its higher than predicted thickness, which did not interfere with the shell functional pore area.

5. The low water vapour conductance of the Sinai egg shell may reflect adaptations to its dry habitat.     

Effects of dietary supplementation with Gynura procumbens (Merr.) on egg yolk cholesterol,excreta microflora and laying hen performance

1. The present study investigated the effects of dietary supplementation with Gynura procumbens on egg yolk and serum cholesterol and triglycerides, excreta microflora, laying performance and egg quality.

2. A total of 160 Hy-Line Brown layers (45 weeks old) were randomly assigned into 4 treatments on the basis of laying performance. Each treatment had 4 replicates with 10 birds each.

3. Dietary treatments were basal diet supplemented with 0 (control), 2.5, 5.0 and 7.5 g/kg diet G. procumbens during 56-d feeding period.

4. Serum (d 21, 42 and 56) and egg yolk (d 28, 42 and 56) cholesterol and triglycerides concentrations were linearly reduced with increasing dietary concentrations of G. procumbens.

5. Increasing dietary concentrations of G. procumbens linearly reduced the excreta total anaerobic bacteria (d 28), Clostridium sp. and Escherichia coli (d 28 and 56) populations.

6. Overall egg production and egg mass were linearly increased, and overall feed efficiency was linearly improved with increase in dietary G. procumbens.

7. Dietary increasing concentrations of G. procumbens linearly improved egg yolk colour (d 28 and 56) and breaking strength of eggs (d 56).

8. The results obtained in the present experiment indicate that dietary supplementation with G. procumbens could reduce the egg yolk cholesterol, suppresses harmful excreta microflora and improves layers performance.     

Asociation of plasma 5'‐nucleotidase and alkaline phosphatase with production traits in chickens: Effects of age and housing systems

1. The housing system, age of pullets and their interaction had a significant effect on plasma 5'‐nucleotidase and alkaline phosphatase activities.

2. Activities were higher in birds in cages than in those on the floor, reflecting perhaps the stress of caging. Activities increased with age.

3. Activities were higher in pullets selected for higher production.

4. The type of housing had no effect on egg production, but age at first egg, egg weight and 40‐week body weight were found to be affected significantly.     

Cross performance as influenced by selection in pure lines

1. The resultant genetic gains in cross performance due to the individual, dam family and sire family (IDS) method of index selection for increased part‐period egg number in their parent lines are described.

2. A randombred control population of known pedigree was used to measure the environmental trends.

3. Selection in pure lines resulted in concomitant improvement in the crosses for the selected as well as the correlated traits.

4. Cross performance was comparatively more than expected on the basis of mid‐parent values, indicating involvement of non‐additive gene action in the expression of cross performance.

5. Crosses responded better to independent culling level selection for egg weight than their parents.

6. Heterosis appeared to increase in later generations as compared with initial generations of selection.     

The utilisation of goose egg nutrients by the developing embryo

1. Eggs and hatched embryos from geese were analysed for their proximate and amino acid composition. In comparison with eggs and embryos of the domestic fowl the following were found.

2. The yolk: albumen ratio of the goose egg was higher.

3. The fat concentration in the egg yolk and the protein concentration in the egg albumen were lower.

4. Deposition of dry matter in the embryo and energy expenditure during incubation were similar. In both species, the nitrogen in the embryo exceeded the nitrogen in the egg contents. This is probably due to the utilisation of egg‐shell membrane proteins.

5. Lysine concentration in the goose egg proteins was lower, which was reflected in the hatched gosling proteins.

6. There were high correlations in amino acid concentrations between chicken and goose eggs and between the efficiencies of amino acid utilisation by their embryos, implying that similar metabolic processes are involved in these two species.     

Comparison of changes in production and egg composition in relation to in vivo estimates of body weight and composition of brown and white egg layers during the first egg-laying period

1. The aim of this study was to compare the changes in the production and in the body and egg composition of 45 TETRA SL brown egg layers and 45 TETRA BLANCA white egg layers during the first egg-laying period.

2. Changes in the body composition of the hens were followed in vivo by means of computed tomography (CT) four-weekly, between 20 and 72 weeks of age. The measurements covered the whole body of the hens using overlapping 10 mm slice thicknesses on a Siemens Somatom Emotion 6 multislice CT scanner.

3. The yolk, albumen and shell ratio of the eggs, produced on the days of the CT measurements by the hens, were determined and their composition was analysed chemically.

4. The body fat content of the hens increased continuously until 44 weeks of age and plateaued thereafter in both genotypes. However, the body fat content of the white egg layers was always higher than that of the brown egg layers.

5. The yolk ratio and the dry matter and crude fat content of the eggs of white egg layers were higher than the brown egg layers throughout the experiment.

6. Moderate correlations were observed in both genotypes between the body fat content of the hens and egg yolk ratio of their eggs.     

Effect of hesperidin dietary supplementation on hen performance,egg quality and yolk oxidative stability

1. The purpose of this study was to evaluate the effects of dietary supplementation with hesperidin (one or 3 g/kg of feed) for 31 d on the performance, egg quality and yolk oxidative stability of brown and white laying hens (26-wk old).

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.     

Effect of gradual acclimation to high ambient temperatures on egg‐shell quality of the Sinai Bedouin fowl,the commercial white leghorn and their crossbreds

1. The effect of gradual acclimation to high ambient temperatures on egg‐shell quality was studied in the Sinai fowl, the commercial White Leghorn, and their reciprocal crossbreds.

2. The Leghorn egg was characterised by a thinner and weaker shell compared with the Sinai and the crossbreds, at all the experimental temperatures.

3. In contrast to other reports, high ambient temperatures for a long period had only mild effects on egg‐shell quality.

4. The results suggest that gradual acclimation to high ambient temperatures might improve the efficiency of the physiological mechanisms involved in the hen's response to heat. Consequently, the reproductive process adapts to the hot environmental conditions.

5. The results indicate that the Sinai breed might be used for future selection of a breed, highly resistant to extreme environmental conditions and with an improved shell quality.     

Physical and chemical nature of eggs from six breeds of domestic fowl

1. The physical nature and chemical composition of the eggs from several breeds, White Leghorn, Rhode Island Red, Sussex, Maran, Dwarf Sussex and English Gamecock, have been studied.

2. The water content was highest in White Leghorn eggs, which were the heaviest.

3. Cholesterol content was similar in all eggs except for Dwarf Sussex in which it was less.

4. English Gamecock eggs contained a higher proportion of protein than those of the other breeds.

5. From the data presented, egg size, under similar conditions of feeding, does not determine the contents of components of the egg, but there are underlying genetic factors.     

Energy requirement of laying japanese quail

1. Two feeding experiments were conducted to determine the meta‐bolisable energy (ME) requirement of laying Japanese quail. Birds were fed to provide 5.5 g protein and 167, 209, 251 or 293 kJ ME/d.

2. As ME intake increased from 167 to 293 kJ egg production increased.

3. Quadratic relationships between ME intake and egg production, ME intake and egg weight, and ME intake and egg mass (g egg/ bird d) were derived and used to determine the energy required for an acceptable production rate.

4. To maintain a production of 8.3 g egg/bird d (90 eggs/100 bird d with a mean weight of 9.3 g) required 260 kJ ME/bird d.     

Relationships between age,shell quality and individual rate and duration of shell formation in domestic hens

1. The duration and rate of shell formation was measured individually in each of 44 hens. Comparisons were made between hens of different ages, and also between hens which laid eggs of differing shell qualities.

2. Shell formation began 9–5 to 11 h after the oviposition of the previous egg, increased linearly for 13 h and then plateaued at 1–5 h before oviposition.

3. The variation in egg shell quality observed in two experimental groups of hens was 75% attributable to differences in the rate of shell deposition and 25% attributable to difference in the duration of shell deposition.

4. The mean interval between ovipositions increased with age but neither shell weight, nor rate or duration of shell depositon were affected. The increase in egg weight with age accounted for the decrease in shell quality.

5. Intervals between ovipositions were positively correlated with the duration of shell formation, especially its latter stages.

6. Egg production was negatively correlated with the interval between ovipositions but not with the duration or rate of shell deposition. There was a negative correlation between duration and rate of shell deposition, except in the case of the hens producing eggs of poor shell quality.     

An appraisal of moulting on post-moult egg production and egg weight distribution in white layer hens; meta-analysis

1. The aim of this study was to establish how different moulting methods and body weight losses influenced post-moult performance and USDA egg weight distribution.

2. Data on 5 laying flocks (#34–38) of the North Carolina Layer Performance and Management Test were used in this meta-analysis.

3. The moulting methods were non-fasted moulted (NF), short feed restricted (SF), 13-d feed restricted (FR), non-anorexic moult programme (NA), non-anorexic moult programme with low sodium (NALS) as well as non-moulting programme as control treatment. The percentages of targeted body weight loss during the moulting period were 20, 24, 25 and 30% of body weight at the end of the first egg production cycle.

4. Post-moult egg production and egg mass were influenced by all moulting methods. Maximum increase in post-moult egg production rate and egg mass occurred with FR and NF programmes, respectively, at 30% of body weight loss, compared to non-moulted hens. Non-fasting methods reduced mortality rate more effectively than fasting methods.

5. Moulting resulted in increases in percentage of grade A and decreases in percentage of grade B eggs. Non-fasting methods increased percentage of grade A eggs more effectively than fasting methods. Percentage of cracked eggs decreased in moulted rather than non-moulted hens and the lowest rate was associated with the NA programme.

6. Post-moult egg weight was not significantly influenced by moulting methods. However, percentage of body weight reduction affected egg weight. The optimum increment in egg weight was achieved by 24% body weight reduction.

7. Overall, non-fasting methods resulted in similar egg production compared with fasting methods. Considering post-moult mortality and USDA egg weight distribution, non-fasting methods, especially NF and NA programmes, performed much better than fasting methods, indicating that non-fasting moulting methods, which are better for animal welfare, are effective alternatives to fasting methods.     

Genetic correlations and heritabilities for frequency of cracked eggs,egg number and egg weight in laying hens

1. Data on egg weight and egg number were obtained from two consecutive generations in a White Leghorn line. Each egg was candled and the frequency of cracked eggs was calculated.

2. The estimates of heritability for the frequency of cracked eggs ranged from 0.11 to 0.43, for egg number from 0.12 to 0.29 and for egg weight from 0.58 to 0.65.

3. The estimates of the genetic correlations between the traits were variable but in general showed no evidence of antagonism between a reduction in crack frequency and an increase in the production traits.

4. The efficiency of selection for reduction in the frequency of cracked eggs based on early measurements is briefly discussed.     

Effect of gradual acclimation to temperatures up to 44 °C on productive performance of the desert Bedouin fowl,the commercial White Leghorn and the two reciprocal crossbreds

1. The effect of daily exposures to increasing ambient temperatures (for 7 months) on egg production was evaluated in the desert Bedouin fowl of Sinai, a commercial White Leghorn and the two reciprocal cross breds.

2. High ambient temperatures did not adversely affect egg weight, laying rate or output per bird (g egg per day per g body weight) of the acclimated hens.

3. Best productivity was attained during periods of exposure to 38 to 40° C in all breeds.

4. Rates of decrease from maximal productivity to productivity at 42 and 44 °G differed with breed. Productivity of Leghorn and Leghorn x Sinai crossbred decreased curvilinearly above 40 °C, while productivity of Sinai and Sinai ( Leghorn crossbred decreased at 42 °C and then stabilised.

5. When changes in egg weight and laying rate were examined on an individual basis (comparison between successive months), the differences between Sinai and the Leghorn were more pronounced.

6. The results support previous findings that the Sinai breed and its crosses are able to withstand extreme environmental temperatures, reflecting genetic adaptation to desert conditions.     

Responses of the reproductive vascular system during the egg‐formation cycle of unanaesthetised laying hens

1. Vascular adjustments to the process of egg formation were examined in the unanaesthetised laying hen, by the radioactive microspheres method.

2. Three‐ to four‐fold increases in blood flow were found in segments surrounding the egg during its passage along the oviduct, possibly due to an enhanced metabolic activity in the muscle layer of the oviduct.

3. Shell‐gland blood flow was minimal in the absence of an egg and increased gradually to a maximum (5‐fold) about 5 h after entrance of the egg into the shell gland. This parallels the rate of calcification of the egg shell.

4. Changes in blood flow in the ovarian follicles and other parts of the oviduct were small while the egg was in the shell gland. This might be typical for the reproductive system of the fowl, which undergoes little structural alteration during egg formation.     

Automated early detection of drops in commercial egg production using neural networks

1. The purpose of this work was to support decision-making in poultry farms by performing automatic early detection of anomalies in egg production.

2. Unprocessed data were collected from a commercial egg farm on a daily basis over 7 years. Records from a total of 24 flocks, each with approximately 20 000 laying hens, were studied.

3. Other similar works have required a prior feature extraction by a poultry expert, and this method is dependent on time and expert knowledge.

4. The present approach reduces the dependency on time and expert knowledge because of the automatic selection of relevant features and the use of artificial neural networks capable of cost-sensitive learning.

5. The optimum configuration of features and parameters in the proposed model was evaluated on unseen test data obtained by a repeated cross-validation technique.

6. The accuracy, sensitivity, specificity and positive predictive value are presented and discussed at 5 forecasting intervals. The accuracy of the proposed model was 0.9896 for the day before a problem occurs.