2. The water vapour conductance of fowl and Muscovy duck egg shells was not affected by the treatment.
3. Cuticle removal increased the conductance of turkey and goose shells, particularly those already relatively porous to water vapour.
4. Removal of cuticles from domestic duck egg shells increased water vapour conductance. In this case the effect was most marked for eggs with lower initial conductances.
5. The differing patterns of resistance to water vapour loss associated with egg shell cuticle are related to the ultrastructure of the cuticle itself, especially the number and size of cuticular fissures.
6. The results suggest that egg shell cuticle is a component in a series of resistances associated with the egg shell and that the use of Fick's Law is insufficient to explain water vapour diffusion across the shell.
7. Embryo survival may be improved by cuticle removal, though this may be limited to those species in which the cuticle restricts water vapour loss in initially low conductance egg shells. 相似文献
2. Sulphanilamide appeared to act mainly by reducing the rate of shell deposition, time spent in the shell gland was unaffected.
3. The thickness of shell components was reduced in a roughly proportional manner in thin shells produced during sulphanilamide treatment.
4. It is proposed that other thin shells in which the component layers are all reduced to a similar extent are also the result of a decreased deposition rate. 相似文献
2. Hens of the population with the high incidence of whitening appeared to be more fearful than hens of the population with the low incidence of whitening.
3. Brown colouration of the egg shell and the incidence and degree of shell whitening declined as the hens aged.
4. Brown colouration and egg shell whitening were most pronounced on the blunt ends of the eggs.
5. A large part of the variation in egg shell whitening was attributable to the individual (hen) component of variance.
6. Differences in egg shell whitening, between the two populations, were detectable throughout the 26 weeks of the experiment.
7. Oviposition intervals were similar for normal and coated eggs when birds were not exposed to disturbance.
8. Disturbance of hens increased oviposition intervals and the incidence and degree of shell whitening, to a similar extent, in both populations.
9. It is concluded that stress‐related egg retention is not the sole factor responsible for abnormal egg shell whitening. Shell whitening may occur as a consequence of the premature termination of shell pigmentation as well as a consequence of the retardation of oviposition which occurs when hens are disturbed. 相似文献
2. Heat exposure of laying fowl resulted in a 1.1°C rise in body temperature, a 10‐fold increase in respiration frequency and mild hypocapnia and hypoxaemia.
3. Plasma and follicular tissue TG concentrations were not significandy affected by heat exposure, but plasma TG specific radioactivity decreased significantly and was negatively correlated with body temperature.
4. The transfer rate of TG to the preovulatory follicles was not affected significantly by hyperthermia.
5. We conclude that nutrient supply to the developing follicles is not compromised in acutely heat‐exposed laying fowl. 相似文献
2. A small but commercially important percentage of the well‐formed eggs of one strain cracked when hc was as low as 3–3 mm and vc 250 mm/s.
3. Characteristics of the egg found to affect hc and vc included the overall thickness of its shell, thickness of its weak inner shell layer and average shell curvature, all measured at the point of impact, and its weight; its age also had a small effect (additional to that mediated through loss of weight); so did the degree of shell ridging.
4. No effect of shell colour was found.
5. Shell damage was typically a single hair‐crack that ran either round the equator or towards a pole. 相似文献
2. The immune response to sheep RBCs was normally distributed in guinea fowl with mean titre at 1.534 ± 0.014.
3. In guinea fowl, effects on titre values of sire and variety (feather colour) were significant whereas sex and sex × variety interaction effects were non‐significant.
4. The estimate of heritability for immune response to sheep RBCs in guinea fowl was 0.35 ±0.17. 相似文献
2. Breeder hens fed ad libitum and subjected to either conventional or intermittent lighting ingested respectively, 25 g and 14 to 17 g more than hens restricted to 115 g/d.
3. Body weight was greater in hens fed ad libitum irrespective of the lighting pattern and of the amount of food intake.
4. Persistency of egg production was impaired by intermittent lighting.
5. Ad libitum feeding reduced egg fertility. The decrease was larger in breeder hens on intermittent lighting.
6. Hatchability was increased in hens submitted to the symmetrical lighting pattern (0.5L:3.5d).
7. Egg and chick weights were higher in hens fed ad libitum.
8. Shell index and shell breaking strength increased in restricted hens on the intermittent lighting pattern (0.5L:3.5d) × 6.
9. The best performance was obtained in restricted hens on the conventional lighting pattern. 相似文献
2. The response in shell thickness to ahemeral lighting was more rapid (2.2 d) than for egg weight (4.2 d).
3. Differences between genotypes were evident in both the speed and magnitude of response.
4. Overall, egg weight and shell thickness on the 28‐h cycle were 7% and 8% greater than on 24 h.
5. The allometric increase indicates that the increase in shell weight was on average 14% more than the increase in egg weight. 相似文献
2. The relevance of these measurements depends on an equivalence of the domestic fowl and the human photopic spectral sensitivity curves, because the latter (CIE) type of curve is the basis of photometric units.
3. A comparison of the data on domestic fowl spectral sensitivity and the CIE‐data, however, shows a serious discrepancy. For most purposes in poultry research, therefore, the lux‐meter is not an appropriate instrument.
4. A better way of presenting the relative luminance of a lamp for domestic fowl ('galluminance') is by multiplying the spectral power distribution of the lamp (Eλ)—as documented by the manufacturer— by the relative spectral sensitivity distribution of the domestic fowl (Gλ).
5. For this purpose we present the log Gλ data in relative units per 5 nm. 相似文献
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. 相似文献
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. 相似文献
2. Deformation was not completely reversible due to crumbling at the points of contact with the force.
3. There are three components of non‐destructive deformation: (a) local deformation at the points of contact, (b) local surface crumbling and (c) deformation of the over‐all shell structure.
4. The latter two are uncontrolled, contributing to errors in the prediction of fracture force and depending on the non‐destructive force applied.
5. These effects should be considered in test selection and interpretation.
6. The optimum non‐destructive force was found to be 1 kg. 相似文献
2. When loading continued until shell failure the mean value of the force at failure, Pf, decreased as the loading rate decreased.
3. Among eggs from a given population the mean value of the product PfRa was related to log ê (dW/dt) in a linear manner, where Ra is the reciprocal of the average curvature of the shell at the point of application of the load.
4. When loading had been halted shortly before the expected time of failure, delayed failure was observed in more than a quarter of the eggs.
5. The more closely the load approximated to the expected load at failure, the shorter the delay in eggs showing delayed failure.
6. There is a risk of loss of eggs through delayed shell fracture if they are stored in stacks of trays that permit some of them to bear loads that are not large enough to cause immediate fracture but are nevertheless fairly large. 相似文献
2. Two-hundred and eighty serum samples of commercial (45 broilers, 20 adult layers and 15 Fayoumi fowl) and wild birds, including 65 peafowl, 45 pigeons, 10 crows, 30 house sparrows, 10 doves, 15 ducks, 10 parrots and 15 guinea fowl, were collected and examined.
3. The percentage of HPS-positive serum samples was 80% in house crows, 78% in pigeons, 7% in house sparrows and 6% in peafowl.
4. The sera obtained from parrots, doves, ducks and guinea fowl were all negative.
5. This study suggests that crows and pigeons could be carriers of the HPS agent. 相似文献
2. Contraction of warm eggs in ice‐cold colloidal iron caused flooding of pore canals and contamination of the underlying shell membranes with this element.
3. Appreciable contamination of the inner shell membrane with iron persisted for 25 d in infertile eggs stored at 37.5 °C. 相似文献
2. In hens receiving a normal diet containing a calcium supplement in a powdery form Pi increased from 25 to 42 mg/1 during an entire shell formation cycle (from 10 to 22 h after oviposition of the previous egg), while in cockerels Pi decreased slightly during the night.
3. This increase in Pi in hens, was not related to cessation of feeding at the onset of darkness but was specifically connected with the beginning of shell secretion.
4. When hens received calcium as crushed sea‐shells separately from the diet, the nocturnal peak in Pi virtually disappeared and only a temporary increase of 4 mg/1 between 10 and 14 h after oviposition remained.
5. These results indicate that the beginning of shell secretion is always accompanied by an increase in Pi and that a separate presentation of dietary calcium reduces the bone mobilisation at night. 相似文献
2. Whole blood viscosity was more than twice as high, and plasma triglyc‐eride and haemoglobin concentrations were over 30% higher in fat line than in lean line females fed ad libitum or in restricted birds of both genotypes.
3. Mean cell haemoglobin concentration was higher and mean cell volume lower in fat compared with lean line females.
4. Food restriction was associated with lower plasma triglyceride concentrations, lower numbers of heterophils and monocytes and a lower heterophil‐lymphocyte ratio.
5. Fat line birds had a higher blood pCO2 and lower pH than lean line birds.
6. Thermal stress was associated in ad libitum‐fed birds with a rise in blood pH and a decrease in pCO2, and in restricted birds with a decline in blood pH and an increase in pCO2.
7. Blood creatine kinase activity increased in all groups under thermal stress. 相似文献
2. With the pheasant as sire, fertility was 7.lb6%, but with the fowl it was 19.lb5%; hatchability of fertile eggs, however, was similar, 42% and 41% respectively.
3. Only one exencephalic hybrid was obtained when the sire was the pheasant but 70 were noted when the fowl was sire. The incidence of this malformation in hatched chicks was 12 times more in crosses with the fowl as sire than in the reverse cross.
4. The frequency of exencephaly was greater with Rhode Island Red, Barred Leghorn or White Leghorn roosters than with Columbian Rock roosters. 相似文献
2. The RQ, data from the gravimetric and the combined gravimetric‐volumetric systems were essentially the same, while differences in O2 and CO2 between the systems were primarily due to variations in environmental temperature.
3. Fasting RQ, was never less than 0.70 in these systems.
4. In the volumetric system the O2, CO2 and RQ, data from the diaferometer were significantly different from the infra‐red and paramagnetic analyses.
5. The CO2 values from the diaferometer were correct, but the O2 values were too low. In the specific analysers the reverse was seen, the paramagnetically‐determined O2 values being correct and the CO2 values from infra‐red analysis being too low.
6. Thus the fasting RQ values from the diaferometer were too high (0.762) and from the specific analysers too low (0.683). 相似文献
2. Citrate significantly reduced pre‐storage PCV of the DF in comparison with the effect of ethylenediamine tetra‐acetic acid (EDTA).
3. It further decreased (P<0.05) the PCV of the blood of DF and GF over 3 d of storage; this was similar to the effect of EDTA on the PCV of the GF blood.
4. Citrate and oxalates induced haemolysis of blood of the DF and the GF in storage faster than EDTA, but overall the haemolysis was more pronounced from red cells of the GF than from those of the DF.
5. The mean fall in the PCV of the DF was significant at 3.0 mg EDTA/ml of blood in contrast to the fall in the PCV of the GF blood. 相似文献