2. The inclusion of AA improved egg production, food intake and efficiency of utilisation, and decreased the cost of food per kg egg. The addition of 400 mg AA/kg diet gave the most efficient performance.
3. Palm oil inclusion reduced the effect of heat stress and increased egg production, egg weight, food intake and efficiency of utilisation.
4. When 200 mg AA and 50 g palm oil/kg were used, additive responses were obtained with further improvements in egg production, food cost and efficiency.
5. Ascorbic acid and palm oil when fed alone or in combination reduced the incidence of cracked eggs.
6. Thus, 400 mg ascorbic acid/kg of diet, 50 g palm oil or 200 mg AA plus 50 g palm oil/kg diet ameliorated the effects of heat stress in laying hens. 相似文献
2. Discolouration prevention methods included treating the meal with ferrous sulphate heptahydrate (FSH), in solution or as crystals, at a 4:1 weight ratio of iron to free gossypol (experiment 1), and reducing its residual lipid (CSL) content to 4.2 g/kg by hexane extraction (experiment 2).
3. In freshly laid eggs, no discolouration was observed when hens were fed a CSM‐based diet containing 250 mg free gossypol/kg and 87 mg CPFA/kg in experiment 1, but slightly brown yolks were produced in experiment 2.
4. Storage of the eggs at 22°C led to yolk mottling, an effect believed to be the initial stages of the brown yolk discolouration.
5. Storage of the eggs at 5°C resulted in enhancement of the brown yolk discolouration, apricot discolouration on surfaces of most yolks and pink albumen discolouration. These effects were prevented when the CSM was extracted with hexane. Apricot yolk and pink albumen discolourations were also produced when hens were fed a non‐CSM diet containing crude CSL at 20.5 g/kg.
6. Dietary CSL increased egg fat saturation, altering the ratios of stearic to oleic, palmitic to palmitoleic and heptadecanoic to hepta‐decenoic fatty acids.
7. Treatment of CSM with FSH reduced the slight brown yolk discolouration in fresh eggs (experiment 2) and the yolk mottling in warm‐stored eggs. Both in solution and as crystals, FSH prevented the enhancement of brown yolk discolouration in cold‐stored eggs, leaving most eggs with apricot yolk and pink albumen discolourations.
8. Treatment of CSM and CSL with FSH reduced the CPFA‐related effects on yolk fat saturation, and the colour and pH changes in cold‐stored eggs.
9. Exposure of yolks to ammonia vapour provided a useful test to predict the development of the gossypol‐related brown discolouration in stored eggs. 相似文献
2. A SAA requirement of about 750 mg/hen d, of which about 425 mg was methionine, was found to be adequate for birds producing on average 51 g egg mass per hen d over 52 weeks. The SAA requirement was found to be higher for maximum efficiency of food utilisation than for maximum egg yield.
3. A diet containing 140 g protein/kg adequately supplemented with methionine and lysine, could sustain laying performance almost identical to that achieved on a diet containing 167 g protein/kg.
4. In diets with 140 g protein/kg the addition of 0.5 to 3.5 g dl‐methionine/kg diet in excess of the requirement did not affect egg production adversely, but food conversion efficiency was decreased. 相似文献
2. The feeding of whole oats halted egg production in 5.7 ±0.22 d and the duration of the pause was 8.3 ±0.78 d.
3. The induction of a pause improved the subsequent rate of egg production, egg output, efficiency of food utilisation, albumen quality, egg specific gravity and shell colour. It also increased food intake and body weight gain but neither egg weight nor the rate of mortality were affected.
4. Neither supplementation of the diet with iron nor its source had any significant effect on laying performance, egg quality or shell colour. 相似文献
2. Lauryl sulphate at 2.5 g/kg or more in the diet significantly increased shell breaking strength, shell thickness and shell weight at 24 and 36 weeks. In 48‐week‐old hens only shell breaking strength was increased significantly. Egg production and egg weight were not affected significantly by lauryl sulphate.
3. Lauryl sulphate might increase these measures of quality by increasing shell deposition and/or shell elasticity. 相似文献
2. A requirement of approximately 775 to 800 mg sulphur amino acids /hen d, of which about 390 to 440 mg was methionine, was found for a maximum of 80 to 83 eggs/100 hen d. There were indications that the requirement for maximum egg production was less than that for maximum efficiency of food utilisation.
3. Diets containing 138 g protein/kg supplemented with methionine and lysine supported production and food utilisation as effectively as a diet containing 167 g protein/kg. 相似文献
2. Egg production and egg mass output were higher with the 190 g protein/kg diets.
3. Lower‐energy diets gave better egg production, while higher‐energy diets containing 190 g protein/kg improved food conversion efficiency.
4. Separation of protein and calcium constituents tended to give better egg production, food conversion efficiency, shell thickness and egg mass output. 相似文献
2. Egg production was reduced in hens fed on diets containing HFM owing to a deficiency in lysine, methionine and tryptophan.
3. Supplementation of the diet containing HFM with 3'0 g lysine (as L‐lysine HC1), 0.7g DL‐methionine and 0.5g L‐tryptophan per kilogram, resulted in a daily egg mass output similar to that achieved with a conventional layers’ diet. 相似文献
2. The total number of yolks laid to 40 weeks was comparable with that of a control line selected for high egg number.
3. At peak production an F1 cross of the two inbred lines laid 140 yolks per hundred hens per day.
4. Double‐yolk selected lines when crossed produced hens with a 20% increased body weight.
5. By the 10th and 11th generations the incidence of eggs with three or four yolks was increasing. 相似文献
2. Twenty five individually caged 20 week‐old Hisex laying hens were used per treatment. The hens were housed in a convection house for the duration of the study which lasted 52 weeks. Two diets were formulated, one containing 300 g sweet lupins/kg and the other containing sunflower oil cake and fish meal as protein sources. These diets were blended to obtain seven diets with lupin inclusion rates of 0, 50, 100, 150, 200, 250 and 300 g/k.
3. Results indicated that up to 300 g lupins/kg diet can be fed to Hisex laying hens without a significant effect on egg production, egg mass, efficiency of food utilisation, egg shell thickness, Haugh units or yolk colour. Food intake was however, significantly (P<0.05) positively correlated with lupin inclusion rates. 相似文献
2. Treatments did not affect egg numbers, food consumption, conversion efficiency of food to egg, bodyweight gain or mortality.
3. Increasing dietary calcium (Ca) significantly increased plasma Ca and inorganic phosphorus (P), breaking strength at the radius and egg specific gravity and significantly decreased plasma alkaline phosphatase and egg weight.
4. Increasing dietary phosphorus increased plasma P and decreased egg specific gravity significantly.
5. Plasma Ca, P and alkaline phosphatase and radius breaking strength were suitable indices of the Ca status of the hens. 相似文献
2. Diet B, as mash, showed a lower apparent physical density than the others. The hardness and durability of the pelleted diets were similar.
3. Hens fed the mash diet B could not completely adjust their food intake to compensate for the dilution and showed reduced egg output and body weight gain compared to the other groups.
4. Video observation of each hen for 14 consecutive hours showed that mash‐fed hens ate for longer periods than pellet‐fed hens during the first 11 h (proportion of time spent eating: 41.3% mash B, 32.5% mash A and 20% to 25% for all the pelleted diets). These differences were less pronounced during the last 3 h of the photoperiod.
5. Trough‐oriented stereotypies were noted in 14 out of 22 mash‐fed hens and in 12 out of 47 pellet‐fed hens. Dilution of the diet did not appear to exacerbate stereotyped behaviours under the conditions of the study.
6. This experiment demonstrates that the feeding behaviour of laying hens is affected by the physical characteristics of the diet and that this may lower their productivity.
7. Low‐energy pelleted diets might be used to feed hens efficiently in tropical countries where cereal by‐products are abundant. 相似文献
2. The hen‐housed laying performance of hens offered the DPM‐containing diets was significantly better for number of eggs laid and total egg mass produced but the performance of the control groups was lower than would normally be expected of those stocks. The reason for the lower rate of lay and higher mortality of hens fed on the control diet was not identified. The amount of food consumed increased as the energy content of the diet decreased and the efficiency of food conversion (EFC) of the lightweight strain was reduced; there was no significant effect on the EFC of the medium‐weight hens.
3. The inclusion of DPM in the diets had no effect on albumen quality or on the incidence of hair‐cracked, cracked or broken eggs. However, with both strains of hens, shell weight and shell thickness were poorer when 100 or 200 g DPM/kg diets were fed. 相似文献
2. In the first a low methionine diet with 2.6 g methionine/kg was supplemented with 0.3, 0.6, 0.9 and 1.2 g DL‐methionine/kg. Choline at 1.12 g/kg was added to the diets, which contained 5.4, 6.0 and 6.6 g TSAA.
3. In the second diets with 3.02, 3.80, 4.53, 5.30, 6.04 and 6.51 g TSAA/kg were used and 0.94 g choline/kg was added to these diets.
4. Supplemental methionine increased egg production but not egg weight in the first experiment. When the low TSAA diet was supplemented with choline, egg output increased slightly but not significantly.
5. When supplemental methionine was added to the low protein and TSAA diets in experiment 2 it increased egg production and egg weight. Added choline did not increase egg production or egg weight, even with the diet very low in protein and TSAA. Body weight gain, food intake and feed conversion efficiency of food utilisation were improved by supplemental methionine but not choline. 相似文献
2. Diets formulated by linear programming contained up to 120 g algae meal/kg with supplementary DL‐methionine.
3. There were no significant effects of dietary algae meal on egg output, food conversion or egg‐shell quality. Thus algae meal at the concentrations tested can be a useful substitute for soyabean meal in diets for laying hens.
4. High concentrations of dietary algae meal caused a deep yellow yolk colour of acceptable appearance. 相似文献
In both experiments maximum egg production was obtained from the birds fed the high‐energy diet ad libitum. Restriction of the concentrated diet caused a significant reduction of body weight gain and a statistically insignificant fall in the total weight of egg product and in percentage production in both experiments.
Restriction of the concentrated diet caused improvements of 22 and 18 per cent in the efficiency of utilisation of metabolisable energy in experiments 1 and 2 respectively.
The data are discussed in relation to the relevant literature and the current cost of concentrated sources of energy. 相似文献
2. The rate of lay in both strains was lower in the older hens. The 82‐week‐old hens were subdivided into good and poor layers: the poor layers produced eggs at about half the rate of the good layers.
3. The yellow‐yolky ovarian follicles in both strains were smaller, more numerous and more closely ranked in hierarchies in 26‐week‐old hens than in 82‐week‐old hens.
4. No marked differences were seen between the strains at 26 or 82 weeks of age in the sizes, numbers or hierarchical arrangements of yellow‐yolky ovarian follicles.
5. The ovaries from 82‐week‐old good and poor layers from both strains contained similar numbers of yellow‐yolky follicles.
6. After feeding a fat‐soluble dye, the number of days over which eggs containing dye were laid did not differ between 26‐, 52‐ and 113‐week‐old hens from an egg laying strain. However, fewer eggs with dyed yolks were laid by the older hens.
7. These observations suggest that the decrease in egg production with age is due initially to a reduction in the rate of recruitment of yellow‐yolky follicles. Towards the end of the laying year it may also be due to an increased incidence of follicular atresia, internal ovulation and the production of membraneous or soft shelled eggs. 相似文献
2. Birds were allocated to 8 treatment groups with 12 replicates (cages) of two hens and were given, from week 26 to 55, iso-caloric and iso-nitrogenous experimental diets with or without a high concentration of DDGS (200 g/kg). The diet containing DDGS was not supplemented or supplemented with enzymes (xylanase and phytase), sodium butyrate, probiotic bacteria (Lactobacillus salivarius) and a mixture of herbal extracts (Taraxaci siccum, Urticae siccum and Salviae siccum), inulin or chitosan.
3. The inclusion of DDGS in the diet had no effect on number of eggs produced, total egg mass, mean egg weight, feed intake or feed conversion ratio. Egg and eggshell quality parameters were also unaffected by dietary DDGS. The yolk colour score (points in Roche scale) was significantly increased by DDGS inclusion. DDGS in the diet caused some changes in the yolk lipid profile that were rather unfavourable from a dietary perspective (an increase of cholesterol content, and PUFA n-6/PUFA n-3 ratio).
4. During the experimental period (26–55 weeks of age) supplementation of the diet containing a high concentration of DDGS with enzymes, inulin as well as chitosan, increased number of eggs produced and daily egg mass. In older hens (50 weeks of age) inulin positively affected eggshell quality parameters, i.e. shell percentage, thickness and density. Diet supplementation with herb extracts, inulin or chitosan, decreased the content of cholesterol in yolks.
5. The results of this study suggest that DDGS may be incorporated up to a concentration of 200 g/kg in the diet of laying hens without any negative effects on egg performance. Moreover, supplementation of xylanase and phytase, as well as inulin and chitosan, can positively affect the performance of layers given diets with a high concentration of DDGS. 相似文献
2. Around 10% mortality and a 20% reduction in egg production was observed. Postmortem examinations showed pale yellow coloured livers with peripheral congestion, mild haemorrhage in the proventriculus and watery accumulations in the intestine.
3. The disease was traced to a new batch of food and its withdrawal improved the health status of the flocks.
4. Analysis of the diet indicated contamination with fumonisin B1 up to 8–5 mg/kg and with aflatoxin B1 up to 0.1 mg/kg.
5. Diarrhoea was induced in day old cockerels by feeding the suspect diet containing 8.5 mg/kg fumonisin Bi, and in laying hens by feeding a normal diet with fumonisin B1 additions of 8 and 16 mg/kg. 相似文献
2. Food intake, egg production and egg weight were measured. Yolk colours were compared with the Hoffman‐La Roche yolk colour fan by a panel of 10 persons on 4 occasions with intervals of 19, 14, 14 and 10 d.
3. Avorophyll had a pigmenting ability for egg yolks but the intensity was 2 to 4 points less on the colour scale fan than calculated on the basis of the pigment content of the diets.
4. Selected panel members showed a high degree of stability in colour discrimination when visually scoring the egg yolks with the colour fan. 相似文献