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. Lighting affected growth pattern but had no effect on body weight at 118 d or overall food to gain ratio.
3. Both INC and DID lighting reduced overall mortality in comparison to CON light primarily because of a reduction in the incidence of skeletal disease and spontaneous cardiomyopathy. INC and DID lighting increased the incidence of cannibalism.
4. Turkeys given INC or DID lighting had a superior ability to walk in comparison to those birds given CON light.
5. INC and DID males stood, ate and drank more frequently, and sat less often than CON turkeys during behavioural observation.
6. There were no lighting effects on carcase composition except that INC and DID birds had heavier keel bones. The ultimate force per cm2 (stress) required to break femora was greater for turkeys given INC and DID lighting (P = 0.065).
7. Plasma testosterone concentrations at 117 d were 272.5, 115.2 and 29.5 pg/ml for turkeys given CON, INC and DID lighting, respectively (P= 0.072). Testosterone concentration was not related to growth rate. 相似文献
2. Fluorescent light showed the same positive correlation between light intensity and physical activity at all activity levels as was found previously for incandescent light.
3. Light‐dependent physical activity under fluorescent light was higher than under incandescent light at illuminances of 5 lux and above, indicating the fowl's ability to perceive qualitative light differences.
4. Total and activity‐related energy expenditure were positively associated with illuminance; resting energy expenditure was not influenced.
5. Total, resting and activity‐related energy expenditure were not statistically significantly different between light sources.
6. The results are discussed in relationship to Teichmuller's concept of adequate lighting and the characteristics of the fowl's visual system. 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. Birds exposed to a 2 h light(L): 10 h dark(D) lighting schedule with feeding restricted to the light periods ate significantly less food and grew more slowly than conventionally‐reared birds. Satisfactory growth and efficiency of food utilisation were obtained by allowing these birds access to food during the dark periods.
3. Altering the lighting schedule to 2L:6D resulted in birds with food intakes and growth rates similar to those reared conventionally, even when feeding was restricted to the light periods.
4. Releasing birds from the light and food restriction for the 2 weeks preceding slaughter resulted in greater food consumption which was not characterised by significantly better growth or food utilisation.
5. Feeding a diet of high energy or pelleting a diet of low energy during the period of restriction increased food intake and improved growth rate.
6. The response of broilers to intermittent lighting and feeding was not significantly influenced by ambient temperature within the range 16 to 35 °C or by the energy concentration of the diet fed before the introduction of the intermittent schedule. 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. 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.?There were two nutrient densities: high (H) starter diet AME 13·39 MJ/kg, 230 g crude protein (CP)/kg: finisher 13·39 MJ/kg, 197 g CP/kg CP) and low (L) starter AME 12·03 MJ/kg, 208 g CP/k; finisher 12·14 MJ/kg, 183 g CP/kg C. The 4 lighting regimes were continuous (CL) 23L:1D, 20L:4D (12L:2D:8L:2D), 16L:8D (12L:3D:2L:3D:2L:2D) and 12L:12D (9L:3D:1L:3D:1L:3D:1L:3D). Blood and lymphoid organs were collected at d 21 and 42 for assay of antioxidant indices and immunity.
3.?Chickens fed low density diet had a higher Fabricius bursa weight (FBW). Low density diet tended (P = 0·089) to increase the a-Naphthylacetate esterase (ANAE) positive percentage response at 42 d.
4.?The 12L:12D schedule decreased serum malondialdehyde compared with other regimes at 21 d. At 42 d, it was lower in the 12L:12D and 16L:8D groups than in CL and 20L:4D. There was a trend (P = 0·086) for greater superoxide dismutase activity in the 12L:12D and 16L:8D groups than under the CL and 20L:4D regimes at 42 d. ANAE positive percentage in 12L:12D group at 42 d was higher than in CL and 20L:4D groups. Plasma IgG in the 12L:12D group at 42 d was higher than in the CL group.
5.?There was an interaction between nutrient density and lighting regime for FBW at 42 d.
6.?These results demonstrate that low nutrient density and a 12L:12D schedule lighting schedule can enhance oxidant-antioxidant balance and the immune functions of broilers. 相似文献
2. Food consumption during the scotophase was negligible. Peak food consumption during the photoperiod occurred at the beginning of the photoperiod and in the late afternoon.
3. During the photoperiod, the crop and proventriculus/gizzard contained only small quantities of ingesta. However, at the beginning of the scotoperiod, dried ingesta content of crop and proventriculus/gizzard increased by 10.5‐ and 2.76‐fold respectively. This increase was followed by a gradual decrease towards the end of the scotoperiod.
4. Food transit time during the scotoperiod was significantly longer than that during the photoperiod.
5. The daily pattern of heat production closely followed the 14L:10D lighting schedule. Total heat production during darkness averaged 53% of total heat production during the photoperiod.
6. It was estimated that the storage of energy (as ingesta) in the crop and proventriculus/gizzard, followed by its gradual release and the increased food transit time during the night, contributed 75.5% of nocturnal energy needs. It must be recognised that these mechanisms play a major role in the energy balance of the growing chicken during periods without food intake. 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. Room treatments were a standard lighting pattern with intensities of 0.5, 2 and 15 lux and an intermittent pattern (3 h light: 3 h dark) at 15 lux. Within room treatments were ad libitum or rationed feeding during rearing and 4 breeds: ISA Brown, Hisex Brown, Shaver Brown and Hisex White.
3. Rationing during rearing, by holding intake at its 6‐week level from 6 to 14 weeks of age, was associated with significantly higher egg production and lower egg weight, but no effect on food intake, or egg output.
4. Intermittent lighting, using a repeated 3L:3D regimen was associated with higher egg weight, but a lower rate of lay, food intake, and total egg output.
5. The absence of a consistent response to light intensity, over the range 0.75 to 12.4 lux was in contrast with earlier work, and it is possible that modern prolific hybrids are more tolerant of low intensity than were earlier stocks.
6. Despite this result it is suggested that current recommendations of 10 to 20 lux in laying houses need not be changed, because such intensities are advisable on the grounds of welfare, staff working conditions and aesthetics. 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. In a period of sexual quiescence on short photoperiods (6L : 18D) LH concentrations were higher during the hours of darkness in both sexes.
3. Transfer to long photoperiods (16L : 8D) stimulated a rapid increase in LH and FSH concentrations. This was maintained for between 2 to 3 months when the concentrations of both gonadotrophins decreased as the birds became photorefractory.
4. Return to short photoperiods had no immediate effect on the concentrations of LH and FSH in females. The concentration of LH was increased during the 3rd week of short photoperiods when the hens were moulting.
5. LH concentrations fluctuated during the ovulatory cycle and were highest about 6 h before ovulation. 相似文献
2. Iiveability in laying hens was improved by the use of intermittent lighting: the degree of improvement was proportional to the reduction in daily illumination achieved by the intermittent programme.
3. The reduction in mortality with intermittent lighting in laying hens was not the result of intermittent lighting per se. Intermittent regimens which did not reduce daily illumination did not reduce mortality.
4. Mortality in both conventionally‐lit laying hens and 49‐d old‐broiler chickens increased with photoperiod. 相似文献
2. Hens received an adequate conventional layers’ diet and the lighting pattern was conventional (17 L:7 D). Observations were made early (31 to 40 weeks) and late (62 to 68 weeks of age) in the laying period.
3. Eggs were classified by position in the clutch sequence and significant negative correlations were found between shell weights of early eggs in the sequence and plasma phosphate at the end of the dark period.
4. No significant trends were found in plasma total calcium.
5. No significant differences were found in bone compositions of birds producing consistently more or less than average shell weight during the laying period.
6. The negative correlations between plasma phosphate and shell weight are consistent with the observations of Sauveur and Mongin (1983) and show that impairment of shell deposition is associated with skeletal mobilisation as indicated by increase in plasma phosphate. This is consistent with the observations on bone composition and indicates that selection for shell quality will tend to select birds which are not dependent on excessive skeletal mobilisation during shell formation. 相似文献
2. Very large egg batches are required to detect small improvements in the hatchability of good hatching strains.
3. Small‐scale laboratory studies on hatchability are best confined to strains and species of low hatchability in which larger between‐treatment differences may be expected.
4. The results of hatchability studies should always be subjected to tests of statistical significance.
5. There is a strong case for studying continuous variates in the laboratory before proceeding to large‐scale hatchability studies. 相似文献
2. Data from a population selected for increased egg production over four generations as well as from a random‐bred control population were available.
3. Heritability of egg number during the first production period was considerably higher than estimates for a second production period, induced by appropriate lighting.
4. Egg weight and body weight were highly heritable. 相似文献
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. 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. Mean oviposition time for both breeds was advanced relative to dusk by approximately 0.5 h for each 1 h extension of photoperiod.
3. Mean oviposition time for the brown egg hybrid was 1.2 to 1.4 h earlier than that of the white egg hybrid under each lighting regimen.
4. A genetic difference in phase setting of the Open Period for Luteinising Hormone (LH) release is the likely reason for the difference in mean time of lay of the two breeds. The difference is possibly one between brown and white hybrids generally, rather than between the particular varieties of hen used in this trial.
5. The proportion of the day in which eggs are laid is shorter under long photoperiods presumably because light at the end of the photoperiod inhibits the pre‐ovulatory surge of LH. 相似文献