2. In only one experiment was weight gain significantly improved when the barley was heated.

3. Autoclaving barley at 120 °C for 30 min reduced dietary dry matter digestibility and treating the barley with dilute acid before heating had no effect on its nutritive value.

4. Supplementing diets containing commercial barley with a‐amylase produced slightly conflicting results in that there was an improved weight gain, food conversion efficiency and digestibility value in two of three experiments.

5. The digestibility and metabolisable energy values of a North American six‐row spring barley (Glacier) were significantly improved by enzyme supplementation.

6. The effect of the enzyme on diets containing a high amylose barley (Glacier Pentlandfield) was positive but not significant.  相似文献   

2. Higher rates of fertility and hatchability of Japanese quail eggs were observed from parents of 10 to 19 weeks of age, with peak fertility and hatchability at 14 and 12 weeks of age, respectively.

3. Sex ratios of 1:2 to 1:5 gave comparable fertility and hatchability results.

4. The hatching performance of quail eggs from cage and deep litter reared breeders was comparable.

5. Fertility and hatchability were directly proportional to the egg weight.

6. Quail egg shell colour, tints and blotches were found to influence hatching performance.

7. Storing quail eggs at 16 ± 2°C and 75 ± 5% relative humidity for more than 4 d reduced hatchability.

8. Hatchability of eggs stored at room temperature was improved if they were sealed in polyethylene bags.

9. Provision of light during the first 14 d of incubation resulted in a photo‐acceleration of about 3.2 h.  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. A mean value for true digestibility of amino acids (TAAD) of 0.837 ± 0.0073 (range 0.780 to 0.862) was derived for ostriches, compared with a mean value of 0.795 ± 0.0258 (range 0.723 to 0.825) for cockerels.

3. True retention of dietary protein was 0.646 ±0.0114 and 0.609 ±0.0643 for ostriches and cockerels respectively.

4. Results in the present study produced evidence that the method for determining metabolisable energy values of ingredients for ostriches is also suitable for measuring the digestibility of amino acids.

5. It was concluded that accurate diet formulation for ostriches requires the assessment of amino acid digestibilities for individual ingredients, because values derived from poultry would underestimate digestibilities for ostriches.  相似文献   

2. Hyperphagia, amounting to twice the intake of control birds early in the experiment, occurred on the repletion day.

3. Final body weight attained 80% of that of the controls.

4. Body fat concentration decreased at first but returned to that of controls after 3 weeks.

5. A consistent hyperlipaemia was observed after food deprivation or restoration.

6. There was a marked increase in the digestive enzymes found in the small intestine, but not in the pancreas during the repletion day.

7. These responses may be considered as mechanisms to reduce the physiological manifestations of starvation.  相似文献   

2. More eggs were produced per hen housed from 30 to 70 weeks in the shallow cages; the difference approached significance.

3. The pattern of feeding activity over the day was significantly more U‐shaped in the shallow cages; this pattern accords more closely with physiological requirements.

4. Feather damage caused by pecking was slightly but significantly more severe in the deep cages at 70 weeks.

5. The proportion of cracked eggs (collected from 60 to 70 weeks) was significantly lower in the shallow cages.

6. The arrangement of the hens was such that within the shallow cages a higher proportion of birds was present in the front half.

7. It is suggested that some of the advantages conferred by the shallow cage may be related to the greater accessibility of the food trough.  相似文献   

Digestibility trials are described, in which cockerels are compared before and after caecectomy; these birds after caecectomy are also compared with normal intact ones of the same age.

The trials showed a reduction in faecal dry matter after caecectomy, indicating that the caeca are active in absorption of water from the digesta. Faecal dry matter content seems to be more characteristic of the bird than of the food it eats.

There was a reduction in the overall digestibility of dry matter in the food after caecectomy, and also in that of crude fibre, though the latter effect is dependent on the food being eaten and on its crude fibre content.

Cellulose digestibility in a given bird was lowered, but the effect is not always evident between one bird and another, indicating that cellulose is digested bacterially in the caecum. No effect was found on pentosan and starch digestion.  相似文献   

2. The data conformed to a mixed model and adjustments were made for the fixed effects sex, hatch date and location. Adjustment improved the precision of the estimates by reducing the error variances significantly.

3. Rearing equal numbers of birds from each family at different locations made the interactions negligible.

4. Weight gain was greater if illumination intensity up to 35 d was less.

5. Females were not heavier on the 1st day but were heavier on the 14th and 35th days than males.

6. Variance components and genetic parameters were estimated.  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. Predation was higher in BA than HB.

3. Mortality through disease was higher in RIR than BA and HB.

4. Crossbred HB birds show the lowest combination of mortality and predation, suggesting a heterosis effect.

5. Mortality did not differ on farms and in field environments, suggesting an inability to improve biosecurity in farm conditions.

6. There was a positive relationship between eggshell strength and mortality. Calcium depletion from the birds’ bones, limiting foraging and escaping ability may be the explanation, which ultimately increases susceptibility to disease and predation.  相似文献   

2. Replacing groundnut oil cake (GNC) by Niger oil cake (NC) on an isonitrogenous basis, did not affect egg production, egg weight or the amount of food required per dozen eggs.

3. The percentage retention of nitrogen from diets containing 30% GNC or 30% NC was similar.

4. The ME value of NC used was 3025 kcal/kg.

5. It is concluded that NC can replace GNC in layers’ diets.  相似文献   

2. Rocking embryo cultures during the first half of incubation enhanced embryo growth.

3. Embryos explanted into ‘surrogate’ eggshells of either other individuals or other species have been successfully ‘hatched’.

4. A normal chorioallantois is formed in these surrogate eggshells. This enables a functional albumen sac to form and eggshell resorption to be achieved.

5. Embryos grown in ‘surrogate’ eggshells are slightly smaller than controls but otherwise normal.

6. The technique provides opportunities for genetic engineering experiments.  相似文献   

2. Chicks on treatments 1 and 2 were fed continuously while those on treatments 3 and 4 were fed during the day (from 06.00 h to 18.00 h) and night (from 18.00 h to 06.00 h) respectively. Chicks on treatment 1 received only natural light during the day, while those on treatments 2, 3 and 4 received supplementary lighting during the night in addition to natural light during the day.

3. Food consumption by birds on treatment 2 was significantly higher at 56 days of age, followed by birds on treatments 1, 4 and 3.

4. The pattern of body weight gains was similar to the order of food consumption.

5. Efficiency of food utilisation was poorest for birds on treatment 2.

6. Mortality rates were not influenced significantly by the feeding regimen and lighting pattern.

7. Dressing percentage and proportion of abdominal fat were greatest for birds on treatment 2.  相似文献   

2.?The experimental diets shared the same basal formulation and were fed to male broiler chickens (Ross 308) housed in individual cages from 12 to 29 d of age.

3.?Xylanase pre-treatment reduced the dietary concentration of arabinoxylan by 15–30%. Pellet durability increased when BSG was ground.

4.?Feed utilisation was significantly higher (6%) when the birds were given coarse BSG rather than ground BSG, whereas there was no significant effect of enzyme treatment. Apparent metabolisable energy was unaffected by the dietary treatments.

5.?The overall starch digestibility was high (99%), with no dietary differences, whereas ileal protein digestibility was low (57%). Xylanase top-dressing tended to improve ileal protein digestibility but, in general, xylanase treatment had no major effect on overall performance in male broilers given diets with BSG.  相似文献   

2. The least floor area (0.035 m²/bird) depressed production in two‐bird cages. Floor area had little effect on the performance of larger colonies.

3. Birds in colonies of three, four or six laid and survived equally well when feeding space/bird and floor area/bird were constant.

4. Production per hen d and food intake were higher, but return on estimated capital outlay was lower, with 102 mm than with 76 mm feeding space/bird when colony size and floor area/bird were constant.

5. Production and food intake of birds which were not treated to prevent cannibalism declined, and mortality increased, as cage depth increased from 385 to 915 mm concomitantly with increasing colony size from 2 to 7 birds and decreasing feeding space from 152 to 43 mm/bird.

6. Increasing cage depth did not increase the proportion of cracked eggs.

7. Mortality was higher among birds fitted with plastic spectacles than among debeaked birds.  相似文献   

2. Photoperiod treatments consisted of computer simulations of day lengths which occur naturally in the spring and autumn of the year. Both photoperiod treatments were given to hens in the autumn and spring.

3. Data were collected for growth evaluations at 2‐ to 4‐week intervals to 16 weeks of age. No significant season × photoperiod interactions occurred.

4. The spring trial resulted in greater body weights and better food conversions (food/gain) than the autumn trial.

5. Simulated autumn daylengths resulted in greater body weights and improved food efficiency at 16 weeks of age compared with simulated spring daylengths.

6. The pattern of growth (period changes) was influenced by season, but not photoperiod.

7. Season and photoperiod both have important and independent influences on the growth of the turkey hen.  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. An Individual Poultry Weighing System (IPWS) was developed to record time, duration, location and body weight of visits of individual hens to 4 weighing scales.

3. The number of hens that visited the weighing scales per 3 h period varied from less than 10 during the dark‐period to more than 60 during the light‐period.

4. The average number of visits per individual hen was 1–4 and the average number of successful weighings per hen was 0–6 during the light‐period.

5. Body weight showed a diurnal rhythm: the difference between the maximum body weight at night and the minimum body weight in the morning was 63 g.

6. The location of the scales influenced number of visits, number of weighings, mean body weight, flock‐uniformity and duration of visits.

7. Body weight per 3 h period did not differ between hens which were individually recognised and those which were not.

8. Flock‐uniformity was 2–6% higher during the light‐period if it was based on weighings of identified hen visits.

9. The average duration of the visits to the scales in the middle of the feeding tier during the light‐period was 63 s.

10. Of all the hens that visited the scales during a 24 h period, 54% visited them only once.

11. Automatic weighing systems without individual hen recognition can deliver reliable management information on mean body weight and flock‐uniformity in aviary systems if the weighing scales are located on the feeding tier in the middle of the house and if they are used during the light‐period.  相似文献   

2. A 25000 kDa purified recombinant derived turkey prolactin (rtPRL), the biological activity of which was tested using a crop sac assay, was used as immunogen for the production of rabbit antiserum. In this biological test, the rtPRL was as active as the ovinePRL.

3. The radioligand (rtPRL) was labelled with ¹²⁵I and the assay allowed the detection of standard doses of rtPRL ranging from 400 pg/tube to 50 ng/tube.

4. No cross reaction with chicken luteinising hormone and recombinant chicken growth hormone was detected.

5. The within and between assay coefficients of variability were 5.0 ± 2.7% and 16.3%, respectively. The overall mean recovery ratio was 1.01.

6. The dose‐response curves obtained with serial dilution of plasma and pituitary from turkey hens at different physiological stages and from male turkeys were parallel to those obtained with standard rtPRL.

7. The measured concentration of prolactin was 5 times higher in plasma from incubating than laying turkey hens, and the pituitaries from incubating hens contained 2 and 4 times more prolactin than those of laying and out of lay hens or males, respectively.

8. To further assess the validity of the assay, we measured changes in plasma concentration of prolactin in turkeys following stimulation with chicken vasointestinal peptide (cVIP). A single injection of 1 or 10 μg/kg body weight of cVIP to laying hens produced a large and rapid increase in plasma prolactin.

9. This new radioimmunoassay appears to be highly specific and sensitive for the measurement of turkey prolactin.  相似文献   

2. It was fed at 16 weeks of age to five separate groups (groups 2 to 6) each of 50 to 60 birds.

3. Group 2 was fed on a normal layers’ diet at 23 weeks of age, group 3 at 27 weeks, group 4 at 31 weeks, group 5 at 35 weeks and group 6 at 55 weeks while the control group (group 1) of similar size to groups 2 to 6 was subjected to a normal commercial treatment for laying stock.

4. In all the experimental groups the onset of sexual maturity occurred normally, but only one or two eggs were laid before laying ceased under the influence of the treatment.

5. Laying re‐started when the hens were fed on a normal diet and production rapidly rose to a high level.

6. Groups 1, 2 and 3 differed little in the total number of eggs produced up to 72 weeks of age.

7. In all experimental groups there were fewer very small, small and medium eggs than in the control group.

8. It is suggested that the use of a low‐calcium diet before the onset of lay may have advantages which could be exploited on a commercial scale.  相似文献