2. In 4 consecutive trials, 4752 hens were recorded for keel bone status. Evaluation of plumage condition was made for 1440 hens and bone breaking strength was recorded for 1200 hens. A total of 4962 eggs were analysed for internal and external egg quality traits. Analyses involved 30 small group compartments per trial.
3. The layer line had a much more pronounced influence on humerus breaking strength than on tibia breaking strength.
4. Plumage condition, particularly on the neck, was positively correlated with humerus breaking strength in both layer lines.
5. An average of 34% of LB and 23% of LSL hens showed keel bone deformities, with higher proportions of slight deformities.
6. Slight keel bone deformities, rather than moderate to severe, increased significantly during the laying period.
7. Stocking density had no influence on bone breaking strength, keel bone status and egg quality traits.
8. LB layers had a 1.4-fold higher humerus, but only a 1.06-fold higher tibia breaking strength compared to LSL layers.
9. Tibia breaking strength was significantly affected by the interaction of group size and layer line. LSL layers in small groups had lower tibia breaking strengths than those of the large groups. 相似文献
2. A circadian system was postulated to control the restriction of ovulation to an 8‐h period of the day under conventional 14 h light: 10 h dark regimes.
3. The final phase of follicular maturation was postulated to commence after ovulation of the preceding ovum in the hierarchy.
4. Ovulation was postulated to occur when a mature follicle was present in the ovary during the appropriate phase of the circadian‐linked system.
5. The predicted times of oviposition were within the standard error of the observed times of oviposition under 21‐, 24‐ and 28‐h photoschedules.
6. It was concluded that this hypothesis for the control of the ovulatory cycle of the hen is consistent with current knowledge. 相似文献
2. Restricted birds were lighter throughout the experiment.
3. Relative adrenal weight tended to be greater in restricted birds but the difference decreased with time.
4. There was no depletion of adrenal cholesterol: from week 5 there was a significantly greater amount in the adrenals of restricted birds.
5. After 1 week of restriction plasma corticosterone concentration was 73% greater than in controls. It decreased progressively, falling within the normal range at 5 weeks.
6. Restricted birds were hypoglycaemic from weeks 2 to 7 and hyper‐lipacidaemic throughout. A negative correlation between plasma glucose and free fatty acids was found. 相似文献
2. Dry plucking increased weight loss due to plucking and eviscerating, and reduced chilled carcass yield.
3. Dry eviscerating increased carcass water uptake during chilling.
4. Pre‐chilling with running water increased carcass water uptake compared with chilling in ice and water alone.
5. Water uptake during chilling appeared to be increased by longer eviscerating time. 相似文献
2. Increased mortality, perosis and other pathological changes involving a number of tissues were observed in birds fed on a low‐choline diet.
3. Methionine replaced part of the dietary requirement for choline at low dietary choline concentrations.
4. High dietary concentrations of choline (> 1 750 mg/kg) increased the requirement for dietary TSAA.
5. Increasing the dietary choline while maintaining the TSAA at an inadequate level may decrease performance. 相似文献
2. The different varieties of wheat investigated contained different proportions of water‐soluble to water‐insoluble hemicelluloses.
3. By comparison of the arabinose to xylose ratios it was concluded that water‐soluble and insoluble arabinoxylans of wheat were branched to the same degree.
4. Starch from six wheat varieties grown in the U.K. was very well digested by adult cockerels and true metabolisable energy values of the wheats were high.
5. Small amounts of cell wall carbohydrates were digested by adult cockerels. 相似文献
2. Growth rate, food intake, food utilisation and proportion of dietary nitrogen retained were much poorer in chicks receiving salseed meal.
3. The chicks receiving salseed meal developed pathological lesions in liver and kidney.
4. The red blood cell count, white blood cell count, haemoglobin concentration and packed cell volume of the chicks receiving salseed meal were lower than those of chicks receiving maize.
5. The apparent metabolisable energy value of salseed meal was determined as 6.83 MJ/kg. 相似文献
2. The Na and water contents of skeletal muscles were increased by TA treatment while K was unaltered.
3. The extracellular space expressed as a proportion of starved body weight was unaffected by TA implantation.
4. Plasma or serum concentrations of P, Ca, Mg, Na and K and activities of the enzymes aspartate aminotransferase [EC 2.6.1.1], creatine kinase [EG 2.7.3.2] and γ‐glutamyl transferase [EC 2.3.2.2] were not changed by TA treatment.
5. Packed cell volume was significantly increased by TA implantation after a delay of some 2 to 3 weeks while plasma protein concentrations were immediately decreased for a period of two weeks before nearly normal concentrations were obtained again.
6. Erythrocyte sedimentation rate was decreased by TA treatment, but serum protein electrophoretic pattern was unchanged. 相似文献
2. Protein content generally increased with age in all muscles and decreased in skin. Protein content in skin of males was always higher than that in females.
3. Moisture content in all muscles decreased with age. In the skin, moisture decreased with age considerably more in females than in males.
4. Fat content increased with age in all tissues, while ash content of breast, thigh and skin decreased with age.
5. Phosphorus, chloride, magnesium and potassium all decreased with age in all the tissues. Thigh and skin calcium content were affected by age, as was the sodium content of drumstick and skin.
6. The sex effect on the inorganic constituents was variable. 相似文献
2. Storage of uneviscerated Wrolstad turkeys at 4 °C for 10 days caused no statistically significant changes in meat flavour or texture.
3. During further storage at —2 °C, however, there was a slight but significant change in flavour, which became more marked with time in birds which had been eviscerated after the initial period at 4 °C.
4. Both eviscerated and uneviscerated birds became slightly tougher during storage.
5. Initial holding at 4 °C increased the numbers of psychrotrophic bacteria on the skin by about 103 but subsequent changes at — 2 °C were slight for uneviscerated birds.
6. Eviscerated carcases had higher counts than uneviscerated birds after storage at — 2 °C and, although ‘off’ odours were not detected, spoilage appeared to be imminent at the end of the 20‐d period. 相似文献
2. Addition of 10 g ascorbic acid/kg to the control diet (without excess tyrosine) produced no beneficial effects on performance. Excess dietary tyrosine caused depressions in all measures of performance.
3. Adding 0.1, 1, 10 or 20 g ascorbic acid/kg to the diet containing excess tyrosine tended to improve performance.
4. Subcutaneous injection of 50 mg ascorbic acid/bird d to chicks receiving excess tyrosine brought about a significant improvement in body‐weight gain.
5. The elevation of plasma free tyrosine caused by excess dietary tyrosine decreased as dietary ascorbic acid increased.
6. Ascorbic acid can alleviate, though not completely counteract, the adverse effect of excess dietary tyrosine. 相似文献
2. The Sinai produced significantly fewer, smaller eggs, resulting in lower egg mass output (g/bird d), than the Leghorn and the crossbreds.
3. Egg weight of both crossbreds was intermediate between Sinai and Leghorn but laying rate was closer to that of the Leghorn.
4. Differences in egg mass output apparent at 8 to 10 months of age decreased considerably with age.
5. These findings suggest that selection or crossbreeding of the Sinai might improve productive performance while maintaining improved eggshell quality. 相似文献
2. Eighty broilers were randomly divided into two groups. Birds in the control group were fed on maize–soybean-based diets. Birds in the treatment group were provided the same diet supplemented with 2 g/kg BA encapsulated in a vegetable oil matrix.
3. At the end of the trial (d 35), pH, bacterial composition and metabolites were determined in the crop, jejunum, ileum and caecum.
4. Growth performance variables and pH were not significantly different.
5. BA concentration decreased rapidly in the proximal gut. However, the treatment diet showed higher BA in the crop, jejunum, ileum and caecum.
6. Total lactate in the crop and D-lactate in the jejunum was higher in the BA treated group. Caecal total and branched chain fatty acids were decreased due to the treatment.
7. Lactobacilli populations were significantly altered by BA supplementation. A trend for increased lactobacilli was observed in the crop, while it became significant in the jejunum and ileum. Lactobacillus species responded differently to the treatment. Four of 5 measured Lactobacillus species, particularly in the ileum, followed the course observed for total lactobacilli; only Lactobacillus salivarius was not modified.
8. Correlation analysis showed that BA modified the intestinal microbiota. Lactobacilli correlated negatively to all studied clostridial clusters and enterobacteria. Clostridial clusters IV and XIVa were significantly increased in the jejunum, whereas only clostridial cluster XIVa was increased in the caecum.
9. Encapsulated BA modified the intestinal microbiota which can lead to the conclusion, that the main beneficial mode of action of BA in the gut appears to be the enhancement of lactic acid bacteria, which in turn may act as a vanguard against pathogens. 相似文献
Objective: It was hypothesized that when DNA in canine plasma was measured by emission fluorometry without prior DNA extraction, the concentration of cfDNA would increase with disease severity.
Animals: The diseased population consisted of 97 client-owned dogs. The clinically normal population consisted of nine client-owned dogs presenting for ‘wellness screens’, and 15 colony-owned Harrier Hounds.
Methods: Plasma cfDNA was measured by fluorometry without prior DNA extraction. The effects of ex vivo storage conditions were evaluated in plasma from two clinically normal dogs. In all other dogs, plasma was separated within two hours of collection. The association between the cfDNA concentration in hospitalized dogs and a variety of clinical, clinicopathological and outcome variables was tested.
Results: The concentration of cfDNA was reliably measured when plasma was separated within two hours of blood collection. The diseased dogs had significantly higher cfDNA than clinically normal dogs (P < 0.001), and the more severe the disease, the higher the cfDNA when severity was categorized according to the American Society of Anesthesiologists (ASA) status (P < 0.001). Dogs that did not survive to discharge had significantly higher cfDNA concentrations than survivors (P = 0.02).
Conclusions/Clinical Importance: The concentration of cfDNA in the plasma of diseased dogs is associated with disease severity and prognosis. Measurement of canine cfDNA could be a useful non-specific disease indicator and prognostic tool. 相似文献
2. Resonances from adenosine triphosphate, phosphocreatine, inorganic phosphate and phosphorous storage protein were observed. These changed in relative intensity as the embryo developed.
3. No ill effects due to exposure to radiofrequency radiation or magnetic fields were observed.
4. It is concluded that topical magnetic resonance can make a useful contribution to the study of embryonic development in avian eggs. 相似文献
2. Biotin deficiency decreased hepatic activity of pyruvate carboxylase [EG 6.4.1.1] but activity of acetyl‐CoA carboxylase [EG 6.4.1.2] was comparatively unaffected.
3. Increasing dietary protein increased the severity of biotin deficiency as assessed by skin lesions and decreased plasma biotin concentrations.
4. The severity of the skin lesions over all the treatments was most closely related to plasma biotin concentration. 相似文献
2. The taint was due to the inclusion of either 25 or 70 g Icelandic capelin fishmeal/kg of the diet.
3. Babcock hens produced significantly more (17%) tainted eggs than Warrens (1.2%).
4. Tainted eggs were significantly reduced to a very low proportion (1.3%) by the third day of feeding a fishmeal‐free diet.
5. The taint was due to the presence of up to 17 mg/trimethylamine kg in affected eggs. 相似文献
2. Salmonellae were not isolated from the empty, cleaned and fumigated houses and only on one occasion from the foodstuffs.
3. Salmonellae were isolated from the environment of the chicks and spasmodically from the litter, water troughs and dust.
4. The incidence of infection of the chicks did not influence the number of isolations of salmonellae from the environment of the birds during rearing.
5. Water in the water troughs rather than foodstuffs appeared to be the major oral route of infection or re‐infection of birds during rearing. 相似文献
2. No difference was found in the qualitative electrophoretic patterns of the anterior pituitary homogenates at different ages and between the sexes.
3. Pituitary PRL concentrations in males were generally higher than in females.
4. Pituitary PRL concentrations in castrated immature cockerels were higher than in intact birds, while PRL concentration was depressed by the injection of testosterone propionate or oestradiol benzoate.
5. Prolactin concentration in intact immature cockerels was decreased by daily injection of testosterone or oestradiol for 3 weeks but not by injection of the hormones for 1 week. 相似文献
2. The Sinai egg was smaller and its shell thicker and stronger than the Leghorn egg. All the differences were statistically significant.
3. Shell thickness and strength of Leghorn eggs were in accordance with values predicted on the basis of egg mass, while those of the Sinai and the two crosses were considerably higher than predicted.
4. The apparent differences in mean egg mass between Sinai and Leghorn breeds did not explain the differences in egg‐shell quality, neither did the shape index which was very similar among all breeds.
5. The findings suggest that the differences in egg‐shell properties are of a genetic origin.
6. The thick, strong and less permeable egg‐shell of the Sinai breed may reflect adaptations to its arid environmental origin and to incubation in the open.
7. These genetically‐determined egg‐shell characteristics might serve in a future selection for improved egg‐shell quality in poultry. 相似文献