2.?A total of 250 one-day-old Ven Cobb broiler chicks were allocated to 5 dietary treatments in a randomised complete block design. The treatments were as follows: (1) positive control with supplemental inorganic P; (2) negative control (NC) marginal in P and ME; (3) NC plus XAP to provide (per kg of diet) 650, 1650 and 4000 U of xylanase, amylase, and protease, respectively; (4) NC plus phytase added to provide 1000 phytase units/kg; and (5) NC plus a combination of XAP and phytase.
3.?Low ME and P in the NC diet depressed weight gain and gain:feed. A cocktail of XAP alone did not improve performance, but phytase supplementation improved weight gain. The enzymes were additive in their effects on growth performance.
4.?The enzymes had no effect on ileal digestible energy. Ileal N digestibility was higher in diets with XAP or phytase individually compared with NC. Both phytase and XAP individually and in combination improved ileal P digestibility compared with NC.
5.?Total tract nutrient retention and ME increased as the birds grew older. There were age × diet interactions in total tract retention of P and Ca; improvement in P retention due to phytase use decreased by 50% as the chicks matured.
6.?The current study shows that a combination of XAP and phytase improved performance, but the enhancement in performance appears to be due mainly to phytase. Both XAP and phytase were effective in improving P digestibility and retention of chicks receiving nutritionally marginal maize–soybean meal.
7.?The data also showed that the chicks benefited more from the enzyme addition at a younger age and that the contribution of the enzymes to nutrient retention decreased with age in chickens. 相似文献
2.?General behavioural activities (feeding, preening, sitting, drinking, cage pecking and beak wiping), open field and locomotor activity tests were conducted to evaluate the effects related to surgery in the immediate 4 d following this procedure. Perfusion of Ringer solution with high K+ after 4 d of guide cannula implantation was used to estimate the neural activity resulting from surgery through stimulation of monoamine release by in vivo brain dialysis.
3.?The results of direct behavioral observations indicated that the stress provoked by surgical guide cannula insertion caused behavioural alterations that are particularly evident in the immediate days following this procedure. Open-field tests on day 4 after surgery showed that, compared to the intact control chickens, the treated chicks had a shorter latency to ambulate and defecate, with more vocalisation. Locomotor activity was less in the treated chicks than inthe controls.
4.?After 4 d of guide cannula implantation, the serotonin concentration started to increase 30 min after the onset of perfusing high-K+ Ringer solution. It reached its highest value at one hour, suggesting that the 4 d after surgery is enough to alleviate some neurochemical dysfunction resulting from surgery. The results of behavioural observations, open-field and locomotor activity tests indicate that the surgical operation caused stress and fear in chicks which persisted up to 4 d. 相似文献
2. Mean temperature in the immediate environment of the chicks was 2.0°C lower than the setpoint of 1 d of age. During the first week this initial temperature difference gradually rose to 1.7°C above setpoint. At 18 d of age a further rise to a mean difference of 4.0°C above setpoint was measured. The difference then remained constant from 32 d of age until the end of the fattening period.
3. It was concluded that the chickens were actually brooded at 30°C. During the rearing period the ambient temperature in the close vicinity of the broilers gradually declined to 26°C.
4. During the finishing period, ambient temperature around the broilers was far above the value recommended for optimal food intake and growth.
5. These results are discussed in relation to heat generation and heat fluxes in the broiler houses. 相似文献
2.?Optimal water loss for maximal hatchability of layer eggs was found to be 12 to 13% of initial egg mass at d 18 of incubation.
3.?Mass specific water vapour conductance (GH2Osp) increased linearly with flock age from 0·31 mg/(d·g·Torr) at the beginning of the first breeding season to 0·40 mg/(d·g·Torr) at its end after 77 weeks (=4·21 and 5·44 mg/(d·100 g·kPa), respectively).
4.?After forced moulting GH2Osp increased from 0·35 to 0·41 mg/(d·g·Torr) (=4·76 and 5·58 mg/(d·100 g·kPa), respectively).
5.?The coefficients of variation of GH2Osp increased with flock age from 14% at the beginning of the breeding season to 31% at the end of the second breeding season.
6.?In order to preserve normal incubation water loss for maximising hatchability, the humidity setting of an incubator should increase gradually, with flock age, from 53% RH to 66% RH in the first laying season and from 61% RH to 67% RH after forced moulting.
7.?A 3·5-fold increase (from 2 to 7%) in the difference between mean and median GH2Osp of egg batches with flock age was found, indicating increasing frequency of microscopic cracks in eggshells with flock age. This has to be taken into account when setting the humidity regime in the incubator. 相似文献
2. Birds reared on rice husk litter showed the greatest food consumption, greatest weight gain, best food conversion efficiency and scored highest in production number.
3. Survivability was also highest with rice husk group (94.4%) but differences in this variable were not thought to be attributable to types of litter.
4. Breast blisters were found only in birds reared on sand (8.3%).
5. It was concluded that rice husk is a suitable litter for rearing broilers on the floor, particularly in paddy‐growing countries. 相似文献
2. Free range (FR) and standard (STD) broilers were killed and processed under commercial conditions and the M. pectoralis major muscle assessed for ultimate pH (pHu), sarcomere length, cooking loss and texture 24 h and 7 d after slaughter.
3. Although FR broilers were females with an average age of 60 d, whereas the STD broilers were 45 d old and predominantly male, there were no significant differences in mean values obtained for pHu, sarcomere length, cooking loss and shear force results between the two bird types.
4. While aging for 7 d increased the pHu and cooking loss means, sarcomere length means remained unchanged and shear force values decreased by 6% and 9% for FR and STD birds respectively.
5. Variability in shear force values also decreased on aging for 7 d, no birds having values above 4 kg/cm2 on day 7 whereas 16% were above this value on day 1.
6. There were significant correlations between the results for shear force, pHu and sarcomere length, indicating that increased shear force values were associated with a decrease in both pHu and sarcomere length.
7. These correlations suggest that variability in the texture of cooked M. pectoralis major from FR and STD chickens is strongly influenced by those post‐mortem biochemical changes which lead to the development of rigor during the early stages of processing. 相似文献
2.?The following treatments were applied from day one: (1) chicks exposed to normal human contact fed basal diet (control); (2) chicks were exposed to unpleasant physical treatment and fed basal diet (UPT-BD); and (3) chicks were exposed to unpleasant physical treatment and fed basal diet supplemented with Lactobacillus (UPT-BDL). Chicks were exposed to UPT from days 1 to 21. Different segments of gastrointestinal tract were sampled at 14, 28, 35 and 42 d of age.
3.?Broilers of UPT-BD had lower feed consumption compared with control group at 7 d of age. Overall, UPT-BDL birds showed higher body weight gain (BWG) and better feed conversion ratio (FCR) over the course of the experiment.
4.?Birds of UPT-BD had lower concentrations of lactic, propionic and butyric acids in the caecum as compared with other groups at 14 d of age. Acetic acid concentration was profoundly decreased in both UPT groups compared to the control.
5.?Duodenal villus height of UPT-BD broilers showed a slight reduction compared to the control and UPT-BDL birds at 14 d of age. Afterwards until day 42, UPT-BDL birds showed the highest villus height among treatments in different parts of the small intestine.
6.?The results suggested that, even though UPT did not have significant inhibitory effects on the development of the small intestine and broiler performance, it negatively affected bacterial metabolic end products in the caecum, which could be ameliorated by the addition of Lactobacillus. 相似文献
2. Data were analysed for species differences in food consumption, body weight, food utilisation, mortality and liver pathology.
3. There were no significant effects of aflatoxin in broiler and Leghorn chicks. Aflatoxin at 0.7 mg/kg decreased the body weight of turkey poults but tended to increase the growth rate of goslings. At 1 ‐4 mg aflatoxin/kg food consumption, body weight and weight gain of goslings were adversely affected.
4. Liver damage occurred in goslings and quail chicks at all inclusions of aflatoxin and was extensive at 2.1 mg/kg.
5. Poults and goslings appeared to be the most sensitive, quail were intermediate and domestic chicks were most resistant. 相似文献
2.?White, 1-d-old, Hy-Line hybrid chicks (n?=?840) were divided into 4 main groups, each comprising 7 replicates of 30 chicks (n?=?210): (1) control; (2) 1000?mg/kg yeast cell walls (YCW) added; (3) 1000?mg/kg Yucca schidigera extract (YE) added; and (4) 500?mg/kg YE?+?500?mg/kg YCW added. The trial lasted 60?d.
3.?Daily weight gain of the chicks was positively affected between d 45-60 in the YE and YCW?+?YE groups compared with the control group.
4.?Overall, feed consumption did not differ between the control and YCW, YE, YCW?+?YE groups during the 60?d study period. Feed efficiency was better in the YE and YCW?+?YE groups than in the control group between d 1-60.
5.?During the 60?d evaluation period, live weight gain, and final live weight were higher in YE and YCW?+?YE groups than in the control group.
6.?Antibody titres against infectious bronchitis and infectious bursal disease did not differ among the 4 treatments, but those for Newcastle disease were higher in the YE?+?YCW groups than in the control, YCW and YE groups on d 45.
7.?There were differences in intestinal histomorphometry between the 4 treatments. The height of the jejunal and ileal villi was greater in the YE and YCW?+?YE groups than in the control and YCW groups
8.?It can be concluded that YCW and YE supplementation for layer chicks is beneficial for growth performance and intestinal histology during the 1-60?d growing period. 相似文献
2. Severity of response to E. coli challenge as measured by lesion scores, and mortality was greater for chicks fed ad libitum than those fed on alternate days. For chicks fed on alternate days, lesion scores were lower for those without access to feed for the 24‐h period immediately after challenge.
3. Spleen weights, the indicator of response to marble spleen disease virus challenge, were higher for chicks fed ad libitum than those fed on alternate days.
4. Antibody response to sheep red blood cell antigen was not affected by feeding regimen.
5. Ratios of heterophils to lymphocytes were higher for chicks given access to feed for the previous 24‐h period than for those fasted during the previous 24‐h or those that had been fed ad libitum.
6. Results of this experiment suggest that for alternate‐day feeding programs, vaccination be administered on the day that chicks are not fed. 相似文献
2. There was a linear decrease in body weight and efficiency of food utilisation with each percentage increase in DPM.
3. The amount of dried droppings recovered as a percentage of food consumed was proportional to the amount of DPM included in the diet and remained fairly constant during the recycling.
4. Body weights and efficiency of food utilisation were substantially the same during the first three recycling periods but declined significantly during the fourth period.
5. Mortality was negligible and all chicks appeared healthy and vigorous.
6. Chicks fed on 10% DPM in an isocaloric and isonitrogenous (protein‐N) diet grew and utilised food as well as those fed on the basal diet; chicks fed on 20% DPM did not consume enough to meet their requirements. 相似文献
2. Plasma AGP concentration increased in the 3 d after hatching, and then stabilised at 240 ± 33 μg/ml up to 14 d of age.
3. No sex‐related differences in plasma AGP concentration were observed up to 6 weeks of age.
4. A single injection of 900 μg LPS per chick resulted in a 5‐fold increase in AGP concentration compared with that in saline‐injected chicks. Multiple injections of LPS (200 μg/chick every 2d for 14d) caused only a 50% increase in AGP concentration. 相似文献
2. Time of day of injection did not modify the response to corticosterone of 3‐week‐old chicks kept under natural daylight nor of 7‐week‐old broilers receiving additional illumination.
3. Pure White Rock chicks and Cornish x White Rock crossbred chicks responded similarly to corticosterone injections at 3 weeks of age.
4. Seven‐week‐old female birds treated with corticosterone had significantly larger abdominal fat pads than similarly treated males.
5. Corticosterone injection was more effective in increasing the proportion of liver fat in 7‐week‐old birds than in 3‐week‐old ?hicks.
6. The increased amount of abdominal and liver fat due to corticosterone injections administered at 3 weeks of age disappeared after 3 weeks, but growth depression was still evident. 相似文献
2. A total of 3,000 fertile eggs from broiler breeders (Cobb®) were randomly divided into three incubation treatments: no ascorbic acid injection and egg incubation at 37.5°C (control); no ascorbic acid injection and egg incubation at 39°C; in ovo ascorbic acid injection prior to incubation (6 µg AA/100 µl water) and egg incubation at 39°C.
3. Male chicks hatched from the three incubation treatments were submitted to three distinct rearing temperatures (control, cold and hot) from the third week of age onwards (540 chicks were divided into 6 treatments with 5 replicates per treatment).
4. Measurements at 42 d showed that, after egg incubation at 39°C, the haematocrit, haemoglobin values, ionised calcium and glucose concentrations were increased and base excess values were reduced. However, in ovo injection of ascorbic acid normalised all these parameters.
5. Partial CO2 and O2 pressure were higher with increased rearing temperature. Blood pH was lower when eggs were incubated at 39°C and injected with ascorbic acid. In ovo injection of ascorbic acid induced leucocytosis due to lymphocytosis and heterophilia, restored basophils rate and led to monocytopoenia. Leucocytosis was triggered by hot rearing temperature due to lymphocytosis, eosinophilia and heterophilia.
6. The results obtained in this study showed that in ovo injection of ascorbic acid before incubation may serve as a long-term stimulator and modulator of the broiler immune system, and that high incubation temperatures induce adaptations in the electrolytic balance, minimising or avoiding the occurrence of respiratory alkalosis under hot rearing temperature. 相似文献
2. An economic model of these responses was developed in which the temperature and age at slaughter are optimised, given food and live body weight prices.
3. If a finisher diet of 13.3 MJ ME and 199 g protein/kg costing 150 £/tonne is fed, and provided the grower diet contains 13.5 MJ and 221 g protein/kg, the optimum temperature is 21 to 22 °C for male and female broilers slaughtered at 61 and 54 d respectively with a live body weight value of £0.50/kg. 相似文献
2. Efficiency of food utilisation, protein efficiency ratio and dressing percentage indicated that substitution of FM or GC by alga did not affect the performance of broilers.
3. None of the diets affected the weights, compositions and histopathology of the various organs of the chicks.
4. Meat quality remained unchanged except for a more intense colour in the case of birds fed on the alga‐containing diets. 相似文献
2. Dietary sulphate and tungstate both reduce the availability of dietary molybdate.
3. No evidence was obtained that either the clubbed down, ginger hair syndrome in chicks or the scabby hip syndrome in broilers is due to a simple molybdenum deficiency. 相似文献
2. The birds spent approximately 67% of their time in a cluster, in which their sensible heat losses were between 30 and 60% of those of an individual bird.
3. Body plus plumage resistance was constant at 0–09 m2K/W up to 30 d and increased linearly to 0–40 m2K/W at 54 d. 相似文献
2. Creatine supplementation of AJB diets markedly enhanced the efficiencies of food and nitrogen utilisation of chicks, restoring these indices to control values. The improvement in nitrogen utilisation was enhanced further on providing creatine with a mixture of 2‐aminoiso‐butyric acid, arginine and lysine.
3. Potassium acetate induced striking improvements in the nitrogen retention efficiencies of chicks fed on AJB diets.
4. Liver weights, as a proportion of body weight, generally increased on feeding AJB diets, the effects being marked with the AJB diet supplemented with arginine and lysine.
5. Hepatic urea concentrations were elevated in all groups receiving AJB. Canavanine, a toxic amino acid component of AJB, could not be detected in acid hydrolysates of livers from chicks fed this legume.
6. Temperature and the volumes of water employed in the preparation of AJB are important determinants of its nutritional value. 相似文献
1. The present study evaluated the effects of a blend of essential oils (EOB; cinnamaldehyde and thymol) and stocking density on the performance, gut microflora, meat quality and physiological stress markers of broilers.
2. One-day-old Ross 308 male broiler chickens (n = 360) were allocated to 4 experimental groups from d 22 to 42. Each treatment had 6 replicates of 15 chicks. Two groups were subjected to a high stocking density (HSD) of 20 birds/m2 and the other two groups were kept at a low stocking density (LSD) of 10 birds/m2.
3. The results of this study indicate that overcrowding stress decreased growth performance parameters, blood immunoglobulin (Ig)G and heterophil:lymphocyte (H:L) ratio but increased IgA and IgM levels. HSD reduced water-loss rate and pH decline at 45 min post mortem in the breast muscle.
4. Essential oils supplementation elevated H:L ratio but decreased breast meat redness and pH24.
5. Significant interactions between EOB and stocking density were observed for corticosterone (CS) level and mRNA levels of heat shock protein 70 (HSP70) in brain and heart. Although HSD increased CS and HSP70 when compared to LSD, the effects of the former were inconsistent with EOB supplemented diets.
6. In conclusion, dietary EOB supplementation could improve some of the biomarkers associated with overcrowding stress in broiler chickens. 相似文献