High-tech astronomy: observational astrophysics     

Canizares CR 《Science (New York, N.Y.)》1989,244(4906):851

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Getting by in a bureaucracy: moral mazes     

Morrill C 《Science (New York, N.Y.)》1989,244(4906):836-837

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Case highlights sensitive issues     

C BJ 《Science (New York, N.Y.)》1989,245(4914):121

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Effect of dietary inclusion of ascorbic acid and palm oil on the performance of laying hens in a hot tropical environment     

P. C. Njoku  Adeline O. U. Nwazota 《British poultry science》1989,30(4):831-840

1. Two experiments were conducted to evaluate the effects of including ascorbic acid (AA), palm oil or a combination of both in the diets of laying hens during the hot months in a tropical environment.

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   

Contribution of lipoprotein lipase activity to the differential growth of three adipose tissue depots in young broiler chickens     

S. C. Butterwith 《British poultry science》1989,30(4):927-933

1. The growth of three distinct adipose tissue depots around the abdomen, neck and thigh was measured in a commercial strain of broiler, and related to the changes in activity of lipoprotein lipase within each depot.

2. At 10 d of age there was no significant difference between the weights of the depots. Thereafter the abdominal fat pad exhibited a much greater rate of growth than the other two depots so that by 55 d of age the abdominal fat pad was 4 times the size of the leg depot and 3.4 times the size of the neck depot.

3. Changes in total lipoprotein lipase activity for all three depots showed a similar pattern to the changes in their weight.

4. When [¹⁴C]‐VLDL was injected intravenously into birds at 15 and 57 d of age the percentage taken up into the abdominal fat pad was greater than that into the other two depots at both ages. At 57 d of age the abdominal fat pad had a 2.3‐fold greater uptake than at 15 d whereas the other two depots showed no significant differences at the two ages.

5. These results provide further evidence for a key role of lipoprotein lipase in regulating adipose tissue growth in broilers. They also demonstrate that although the abdominal fat pad has been used in a number of studies of adipose tissue metabolism it is not necessarily representative of other depots.  相似文献   

Authors' reply          下载免费PDF全文

Quine JP  Strunin L 《The Canadian veterinary journal. La revue veterinaire canadienne》1989,30(1):10-11

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Alleviation of postanesthetic hypoxemia in the horse   总被引：1，自引：0，他引：1       下载免费PDF全文

McMurphy RM  Cribb PH 《The Canadian veterinary journal. La revue veterinaire canadienne》1989,30(1):37-41

This study was designed to investigate the effect of the nasotracheal insufflation of oxygen at a flow rate of 15 L/min on the arterial partial pressure of oxygen during the recovery period following inhalation anesthesia in the horse. It has been stated that this is a suitable flow rate to prevent postoperative hypoxemia but without any experimental evidence to support those statements. Horses being used for the study of healing of cartilage were anesthetized on two separate occasions. Following one period of anesthesia they were allowed to recover breathing room air, and following the other period of anesthesia oxygen was insufflated into the trachea at 15 L/min throughout the recovery period. This permitted each horse to act as its own control and allowed statistical analysis using Student's t-test for paired samples.

The insufflated horses had a higher arterial partial pressure of oxygen during the recovery period than did the noninsufflated horses (p < 0.05).

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Morphological study of bacterial pneumonia of feedlot cattle: Determination of age of lesions          下载免费PDF全文

Daoust PY 《The Canadian veterinary journal. La revue veterinaire canadienne》1989,30(2):155-160

Lungs from 48 feedlot cattle that had died from bacterial pneumonia were examined grossly and microscopically. Criteria based on microscopic lesions were adopted to age these pneumonias. In 38 cases, pneumonic lesions were of relatively uniform age throughout the affected tissue. In eight other cases, the presence of older lesions confined to one or two lobes suggested a previous episode of pneumonia. The aging criteria adopted were in agreement with the duration of the observed clinical signs in 26 cases. In 13 other cases, the pneumonia was estimated to be of longer duration than suggested by the history, whereas in the remaining nine cases, it was estimated to be more recent. Areas of tan discoloration of the parenchyma surrounded by white or yellow borders were considered the best areas to examine microscopically since they offered the best chances of revealing necrosis and fibrosis, the main lesions used to age the pneumonia.  相似文献   

Atrophic rhinitis of swine--a multifactorial disease?     

P Sch?ss 《Berliner und Münchener tier?rztliche Wochenschrift》1989,102(11):387-389

Atrophic rhinitis is caused by toxigenic Pasteurella multocida strains. The infection is supported by Bordetella bronchiseptica and other widespread agents and by non-infectious factors damaging the nasal epithelium. The term "infectious multifactorial disease" means in German, that ubiquitous low-virulent agents cause disease when intensified by non-infectious factors. Atrophic rhinitis does not belong to this group but is an infectious disease, caused by a specific agent and influenced by several factors.  相似文献   

Rearing temperature and the meat yield of broilers     

M. A. R. Howlider  S. P. Rose 《British poultry science》1989,30(1):61-67

1. One hundred and twenty (60 male and 60 female) 21‐d‐old Ross 1 broiler chicks were reared in cages in rooms kept at 21°C or 31°C and were killed at body weights of 1.0, 1.5, 2.0, 2.5 or 3.0 kg.

2. Birds reared at either of the two temperatures ate similar quantities of food to reach their slaughter weight although at 31°C they took longer to reach it.

3. The meat yields of the birds at each slaughter weight were similar at both rearing temperatures, but at body weights greater than 2.0 kg, the broilers reared at 21 °C had more breast meat than those reared at 31°C.

4. Females ate more food than males to reach each of the slaughter weights. The females deposited more fat and had a greater skin weight than the males and, although they had a similar amount of total meat, they had more breast meat.  相似文献