Influence of dietary osteolathyrogens on the ultrastructure of shell and membranes of eggs from laying hens

1. Laying hens were fed osteolathyrogens, either semicarbazide hy‐drochloride at 0.3 g/kg or β‐aminopropionitrile fumarate at 0.6 g/kg, to examine their effects upon the ultrastructure of shell and shell membranes by scanning electron microscopy.

2. Effects of the 2 lathyrogens were similar. Compared with the highly‐branched network of fine fibres in normal membranes, there is widespread lack of separation of fibres in lathyritic specimens and hence, uneven distribution of nucleation sites. Pores are also uneven in size and distribution, which can account for increased permeability.

3. Establishment between shell and membranes is reduced. Within the cone layer both type A and type B mammillary bodies occur. Large interstitial spaces and late fusion of the palisade layer indicate reduced resistance to fracture.     

Bacterial growth in albumen taken from the eggs of domestic hens and waterfowl

Gram‐negative bacteria formed small populations in albumen taken from the eggs of domestic hens. Adding yeast extract (final concentration 100 mg/ml) to the albumen did not increase the extent of microbial growth. Large populations were formed in albumen containing FeSO₄.₇H₂O (final concentration 9.95 mg/ml) or this sulphate and yeast extract and the organisms utilised the glucose of the egg white with a concomitant increase in the CO₂ released to the atmosphere. The rate of glucose utilisation, as judged by the rate and extent of the change in pH, was slow in albumen of the eggs of domestic hens to which had been added a heavy suspension of a fermentative bacterium. The retardation of glucose fermentation was a feature also of the albumen of eggs of several species of waterfowl. Both the rate and extent of glucose fermentation was increased when yeast extract (final concentration 100 mg/ml) was added to heavily seeded albumen but ferrous sulphate did not have a significant influence on the rate of glucose utilisation.     

鲎素抗菌肽对蛋鸡产蛋后期蛋品质及蛋壳超微结构的影响

旨在探索鲎素抗菌肽对海兰褐蛋鸡产蛋后期蛋品质及子宫CaBP-D28k mRNA表达量的影响及其机理探讨。随机选取600只385日龄海兰褐蛋鸡,分为对照组、试验组,每组各3个重复,每个重复100只鸡。对照组饲喂基础日粮,试验组在基础日粮中添加鲎素抗菌肽,鲎素抗菌肽发酵液最适添加剂量为0.01 L/kg,按饲料所需量配比添加,预饲期7 d,试验期35 d。结果显示,与对照组相比,试验组产蛋率提高8.86%(P0.05),料蛋比、破蛋率分别降低2.68%和12.76%(P0.05);试验组蛋壳强度比对照组提高了18.97%(P0.05),哈氏单位、蛋壳相对质量和蛋壳厚度均有上升的趋势;试验组蛋壳表面皴裂纹数较少,裂隙变小,纵切面结构中垂直晶体层完整,栅栏层结构整齐,上下层面平滑,栅栏层气孔数量少,乳头层乳头数目少且宽;试验组蛋鸡子宫内CaBP-D28k mRNA表达水平显著提升(P0.01)。可见,鲎素抗菌肽可提高CaBP-D28k参与产蛋过程中钙的代谢过程,调控蛋鸡体内钙代谢发挥功能作用。     

Correlation between shell colour and ultrastructure in pheasant eggs

1. The histochemistry and ultrastructure of pheasant eggs were compared on the basis of blue or brown shell colour. 2. Differences in lectin histochemistry of the outer shell membrane calcification surface indicate a biochemical disruption of the calcification sites in blue eggs. 3. Significant differences were observed in all aspects of eggshell ultrastructure with blue eggs having thinner shells with structural defects. 4. Poor hatchability of blue eggs may reflect high rates of weight loss associated with a defective eggshell.     

绿壳蛋土鸡若干种质特性的研究

实验对绿壳蛋土鸡生长发育等有关特性进行观测，结果表明：公鸡的生长速度比母鸡快，到13周龄时公母鸡体重分别为1355g和1067g；公鸡的胫长、胫围、龙骨长、胸角测定值高于母鸡，而体斜长、胸围、胸宽、胸深公母鸡相差不大；上述各体尺与体重的相关系数分别为-0．623、0．278、0．868、-0．013、-0．081、0．585、0．608和0．108：13周龄公母鸡在屠宰性状方面存在差异，公鸡的腿肌率、胸肌率、翅膀率、全净膛率和半净膛率分别为26．2％、18.3％、13．8％、89．2％和70．9％，母鸡为19．4％、13．9％、11．0％、90．4％和72．5％，公鸡的腿肌率、胸肌率和翅膀率高于母鸡，而半净膛率和全净膛率却比母鸡低。     

Correlations between shape index and shell deformation of hens’ eggs over a laying year

The egg shape index and shell deformation of 2466 pullet and 2214 hen eggs have been studied each week over a period of 45 weeks. The weekly and 5‐week averages were utilised for correlation analysis.

A pronounced negative correlation between shape index and shell deformation variations was found for both pullet and hen eggs. The pullet egg correlation coefficient, determined on the basis of the weekly and 5‐week averages, was ‐0.605 and ‐0.885, respectively; while the corresponding values for hen eggs were ‐0.433 and ‐0.510.

It has been pointed out that although a correlated variation of shape index and shell deformation with time might be due to specific conditions, it is reasonable to assume that if the time‐dependent changes of the relevant properties were taken into account in the investigations, an improved correlation might be expected.     

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.     

Progesterone and testosterone elicit increases in the duration of shell formation in domestic hens

Injection of progesterone or testosterone in hens 4 and 10 h after ovulation increased the intervals between ovipositions and shell weights. The effects were dose-dependent. Expulsion of the egg from treated hens at the expected time of oviposition suppressed the increase in shell weight and deposition of the cuticle. The duration of shell formation had therefore been increased by the injections of progesterone or testosterone. Injections of progesterone 16 h or of testosterone 15 h after ovulation advanced oviposition and reduced shell weight. Testosterone propionate was more efficient than testosterone in its action on the duration of shell formation. Oestradiol was ineffective. Indomethacin delayed oviposition but did not change the duration of shell formation. These results suggest that the duration of shell formation is under the control of hormonal factors and that the larger follicles of the ovary, may be involved in its control.     

Influence of the microstructure on the shell strength of eggs laid by hens of different ages

1. The eggshell is a bioceramic material constructed of columnar calcite crystals preferentially oriented with their c-axis perpendicular to the shell surface. 2. The influence of microstructure (crystal size, shape and crystallographic orientation of crystal grains) on the mechanical properties of eggshells (shell strength) was investigated using eggs from hens of different ages. 3. There was a strong correlation between crystallographic texture and the strength of the eggshell in the case of eggs laid by young hens. The strength of eggshells increased as the preferential orientation of the crystals constituting the eggshell decreased. 4. By comparing two age populations, the effect of hen age on eggshell properties was evaluated. In general, eggshells from aged hens had a lower breaking strength (less than half that of those laid by young hens) and showed a greater variability in their structural properties such as thickness, grain morphology and crystallographic texture. 5. Texture analysis revealed that shells from eggs laid by aged hens have two preferred crystal orientations, after (001) and (104), compared with mainly one, after (001), in eggs laid by young hens. 6. These observed changes in eggshell properties could be due to changes in the organic matrix of the eggshell associated with ageing of the hens.     

Chromatographic analysis of lypophilic compounds in eggs from organically fed hens

Egg yolks represent a common foodstuff in the human diet and are an important source of nutrients including lipids and carotenoids. The aim of this study was to compare the carotenoid, fatty acid and vitamin E contents of the yolk of eggs from nine hen breeds (Barred Plymouth Rock, Speckled Italian, Black Italian, Red Italian, Rhode Island, Silver Laced Wyandotte, Gold Araucana, Partridge Brahma and Yellow Cochin) raised in barns in an enclosed house. Gas chromatography-mass spectrometry (GC-MS) was used for the fatty acid analyses, and reversed phase-high performance liquid chromatography-photodiode array detection (RP-HPLC-PDA) for carotenoids and vitamin E quantification. The major carotenoids identified were lutein and zeaxanthin, which together represented more than 93% of the total carotenoids, followed by β-cryptoxanthin and β-carotene.The results indicated that the total carotenoid content of the eggs ranged from 16.84–87.31 μg/g egg yolk (average value 49 μg/g egg yolk). The most representative fatty acids found were palmitic acid, stearic acid, oleic acid and linoleic acid. Significant differences in the proportions of α-linolenic acid were observed among the samples. The α-tocopherol content was directly correlated with the total carotenoid content. The results show that the chemical composition of egg yolk varies greatly among hen breeds.     

大豆黄酮对产蛋鸡蛋壳品质和骨骼代谢的影响

大豆黄酮(Daidzein)属于异黄酮类植物雌激素(Isoflavonic phytoestrogen)，主要存在于豆科的蝶形花亚科植物中。20世纪90年代以来，国外流行病因学研究证明，膳食中的异黄酮具有防癌和抗癌的作用，使人类乳腺癌、结肠癌发病率降低，近年来动物营养研究表明大豆黄酮具有促进动物生长，增加产     

Incidence of non-laying in domestic hens.

1. Egg production records of 31,455 individually caged hens, 27 to 34 weeks of age and of 4 genotypes, were examined. 2. Sixty-nine non-layers were identified in the 30 to 40 week age group, and examined post mortem; an incidence of 2.1 per 1000. 3. Some of the 69 individuals had more than one abnormality. Forty-two percent were internal layers, 34% had some form of neoplasia, 24% had an abnormal or diseased oviduct, 18% were sex reversals, 16% had a diseased ovary, 8% were of poor condition and considered culls, and 7% were in good condition, but with small, immature ovaries. 4. Of 54 birds not in lay at 27 weeks, 43 (80%) had come into lay by 34 weeks of age. 5. Genotype influenced the incidence of neoplasia and, in turn, the number of non-layers.     

Effect of prior serial in vivo passage on the frequency of Salmonella enteritidis contamination in eggs from experimentally infected laying hens

Experimental infection models are valuable tools for understanding and preventing the deposition of Salmonella enteritidis inside eggs. Oral inoculation is believed to closely simulate naturally occurring S. enteritidis infections of chickens, but oral infection studies have often generated relatively low frequencies of egg contamination. The present study assessed whether repeated in vivo passage of an S. enteritidis strain could affect its ability to cause egg contamination in experimentally infected hens. The incidence of egg contamination was determined in groups of hens inoculated orally with either a phage type 13a S. enteritidis strain or derivatives of this parent strain that were obtained by three successive rounds of passage and reisolation from tissues of infected hens. Passaged S. enteritidis isolates recovered from ovaries and oviducts induced a significantly higher incidence of egg contamination (16.97%) than was attributed to the parent strain (8.27%). However, passaged S. enteritidis isolates recovered from livers and spleens were not associated with a significantly increased frequency of deposition in eggs. By either inducing or selecting for the expression of relevant microbial properties, passage of S. enteritidis through reproductive tissues of chickens may be useful for improving the efficiency at which experimental infection models produce egg contamination.     

The hen's egg: Genetics of taints in eggs from hens fed on rapeseed meal

1. Fishy taints in eggs from hens fed on rapeseed meal, which have been reported to occur in brown‐shelled eggs of some hens with Rhode Island Red ancestry, occur also in white‐shelled eggs of some hens of a strain of Brown Leghorns.

2. Genetic tests have demonstrated that tainting in these circumstances is conditional on the presence in the hen, in the heterozygous or homozygous state, of an autosomal semi‐dominant mutant gene that has variable expression, depending on environmental factors (including the rate of ingestion of rapeseed meal).

3. No simple test for the presence of this gene, applicable to either sex, can be anticipated at present.     

Egg quality and lipid composition of eggs from hens fed Camelina sativa

The present study was conducted to investigate the effect of feeding Camelina sativa to layer birds on egg production, egg quality characteristics, egg lipids, and fatty acid and lipid oxidation products. Fifty-eight-week-old ISA Brown Leghorn laying hens (n = 48) were kept in individual cages and were fed a corn- and soybean meal-based diet with added Camelina meal at 0%, (control), 5%, (CAM5), 10% (CAM10), and 15% (CAM15). The experimental diets were fed for a period of 80 d. Hen-day egg production was lowest for CAM15 (P < 0.05). A significant reduction in yolk weight was observed for CAM10 and CAM15 eggs when compared with control eggs (P < 0.05). Yolk weight, as a percentage of egg weight, was lower for CAM10 and CAM15 eggs, whereas albumen weight, as a percentage of egg weight, was higher in CAM10 and CAM15 eggs than in control eggs (P < 0.05). The yolk:albumen ratio was higher in control eggs than in CAM10 and CAM15 eggs (P < 0.05). Egg total fat content was lowest for CAM15 eggs and was 31.5, 31.9, 30.8, and 29.5 for control, CAM5, CAM10, and CAM15 eggs, respectively (P < 0.05). Total n-3 fatty acids constituted 0.32% in control eggs compared with 2.54, 2.69, and 2.99% in CAM5, CAM10, and CAM15 eggs (P < 0.05). An 8-fold increase in docosahexaenoic acid was observed in CAM15 eggs when compared with control eggs (P < 0.05). The n-6:n-3 ratio was 14.8, 5.6, 4.6, and 4.3 for control, CAM5, CAM10, and CAM15 eggs, respectively (P < 0.05). Total saturated fats were lowest for CAM5 and CAM10 eggs. Eggs from the CAM15 regimen had higher TBA-reactive substance values (P < 0.05) than those from the CAM5, CAM10, or control regimen. Camelina meal could be incorporated into poultry rations as a source of energy, protein, and essential n-3 and n-6 fatty acids. However, inclusion of more than 10% Camelina meal in the hen diet may affect egg lipid quality aspects. Therefore, measures for minimizing lipid peroxidation should be used to enhance egg quality and lipid stability.     

酵母硒对绿壳蛋鸡生产性能、蛋品质、抗氧化能力及蛋黄硒含量的影响

试验选用270只44周龄健康江西东乡黑羽绿壳蛋鸡,随机分成3组,每组5个重复,每个重复18只鸡,采用单因子完全随机试验设计,1组为对照组,2、3组在饲喂相同基础日粮基础上分别以酵母硒形式添加Se 0、0.25、0.50 mg/kg,预试期7 d,正试期28 d。结果表明,在基础日粮中添加0.25、0.50 mg/kg对平均蛋重、产蛋率、合格蛋率、料蛋比和死淘率均无显著影响(P>0.05),可极显著减缓蛋在贮存过程中蛋白质品质的下降(P<0.01),极显著升高蛋黄中硒的含量(P<0.01);显著或极显著提高蛋鸡血清总超氧化物歧化酶、谷胱甘肽过氧化物酶活性(P<0.05或P<0.01)和总抗氧化能力(P<0.01),极显著降低血清丙二醛含量(P<0.01)。综合考虑,基础日粮中酵母硒的适宜添加量为0.25 mg/kg。     

Nesting and floor laying by domestic hens in a commercial flock

1. The nesting behaviour of broiler breeders was studied in a commercial flock of nearly 4000 birds kept on deep litter by tagging a sample of 200 hens. Use of nest boxes by tagged birds was recorded on 52 d over 34 weeks.

2. Forty hens were never observed in nest boxes and 33 others were recorded only in ground‐level boxes. These 73 birds were recorded significantly less often in nest boxes and more often apparently laying on the floor than others. Fewer of them perched during observations and they started doing so later than birds which used raised nest boxes.

3. These results suggested that there were consistent floor layers, which had difficulty reaching raised nest boxes, as found previously in experimental conditions. Many or all floor layers may, however, have used ground‐level boxes sometimes.

4. Hens were inconsistent in their use of particular nest boxes, and some even nested in two distinct areas.

5. Most individuals were, however, consistent in their reaction to one or more features of the nest boxes, including height, aspect and area. Individual choices for these features varied, so no boxes were used particularly heavily, with the exception of those at ground level.     

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.     

Effect of moving dawn, dusk, or both on oviposition time in domestic laying hens

1. Lohmann Brown pullets were reared on 8-h photoperiods and transferred to 12 h at 15 weeks by either advancing dawn or delaying dusk by 4 h. At 25 weeks, half of each group was transferred to 16 h by advancing dawn or delaying dusk and, 10 d later, each photoperiod-group was advanced or delayed 4 h by moving both dawn and dusk. Individual oviposition times were recorded over 48 h at 25 weeks and 8-10 d after each lighting change. 2. At 25 weeks, there were no differences in mean time of oviposition, eggs laid in the modal 8 h, or in the proportion of eggs laid before dawn between pullets that had been given a 4-h increase in daylength at 15 weeks by advancing dawn and those photostimulated by delaying dusk. 3. Extensions of the daylength from 12 to 16 h at 25 weeks, whether by advancing dawn or by delaying dusk, delayed mean oviposition time by 2 h and virtually eliminated egg-laying before dawn. All groups laid > or = 94% of eggs in the modal 8 h. 4. Moving the complete 12- or 16-h photoperiod forwards by 4 h delayed egg-laying by 0.5 h (relative to dawn), whilst moving them backwards advanced it by 0.7 h. Pullets given 16 h of light laid very few eggs before lights-on, but the divergent movements in oviposition time, relative to dawn, resulted in more eggs being laid before lights-on when the 12-h photoperiod was moved backwards and fewer eggs when it was moved forwards. However, a slower adjustment to the new times of dawn and dusk by the pullets whose day had been moved forward, as indicated by fewer eggs being laid in the modal 8 h and poorer rates of lay compared with pullets that had their photoperiod moved backwards, may explain these differences. It is doubtful that the differences would have persisted after all birds had adjusted their ovulatory cycle, and so any reduction in pre-dawn egg-laying is likely to have been transitory. 5. The only permanent way to minimise pre-dawn egg-laying in brown-egg hybrids is to provide a photoperiod of at least 16 h, though 14-15 h may be long enough for white-egg hybrids and 12-13 h sufficient for broiler breeders.