So many promises to keep     

Kerr RA 《Science (New York, N.Y.)》1993,262(5132):332

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Superphenix set to rise again     

Dorozynski A 《Science (New York, N.Y.)》1993,262(5132):327

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A revealing tool     

Kelley SA 《Science (New York, N.Y.)》1993,260(5112):1357-1358

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Growing a diverse lab culture     

Gibbsons A 《Science (New York, N.Y.)》1993,262(5136):1131

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Molecular electronics: observation of molecular rectification     

Waldeck DH  Beratan DN 《Science (New York, N.Y.)》1993,261(5121):576-577

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The life history of galaxy clusters     

Finkbeiner A 《Science (New York, N.Y.)》1993,261(5117):28-30

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Response     

Galione A 《Science (New York, N.Y.)》1993,262(5133):585-586

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Star wars in context     

Greb GA 《Science (New York, N.Y.)》1993,260(5109):831-832

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Effect of dietary protein content on growth and body composition of fast and slow feathering broiler chickens     

O. A. Ajang  S. Prijono  W. K. Smith 《British poultry science》1993,34(1):73-91

1. Broilers were produced from two lines of breeders selected for three generations for fast and slow feather growth. The base population foundation stock originated from a commercial pedigree female line, which carried only the dominant sex‐linked late feathering gene K. Three isoenergetic (12.7 MJ AME/kg) starter and grower diets were formulated to contain 280, 240 and 200, and 260, 220 and 180 g/kg protein, respectively, and fed to 156 broilers of each sex to give three starter‐grower combinations.

2. Broiler performance in terms of growth, food conversion ratio, carcase meat, fat and protein content was optimised on the 240 to 220 g/kg protein starter‐grower series of diets.

3. Birds of the slow line were significantly (P<0.05) heavier at 48 d of age and had the same food intake and food conversion ratio as birds of the fast feathering line.

4. The slow line birds had significantly (P<0.01) shorter feathers and less total plumage weight at 48 d. The slow line birds had significantly (P<0.001) less carcase fat and significantly (P<0.05) more carcase protein than the fast line. The slow line had significantly more carcase meat (P<0.01) within which a greater breast meat yield was evident (P<0.001).  相似文献   

Effect of cold stress on performance and immune responses of Bedouin and white leghorn hens     

M. Spinu  A. A. Degen 《British poultry science》1993,34(1):177-185

1. Bedouin chickens are kept in deserts mainly for eggs and are well adapted to arid conditions. However, deserts are also characterised by relatively cold winter nights. As a consequence of cold stress there is an involution of lymphoid organs and a depression of immunological function. We compared the performance and immunological responses of Bedouin and White Leghorn hens kept in outdoor pens in the Negev Desert during the winter.

2. Initial mean body mass was similar for the two breeds: 1525 g for Bedouin hens and 1542 g for White Leghorn hens. White Leghorns lost 7–74 g/d, compared with 0.60 g/d for Bedouin hens and produced 0.36 eggs/d, compared with 0.54 eggs/day for Bedouin hens.

3. The heterophil/lymphocyte ratio for Bedouin hens was 0.28, which was lower than the 0.44 for White Leghorn hens. Phagocytic index was higher in Bedouin hens than in White Leghorns. Furthermore, wattle index measured 24, 48 and 72 h after PHA injections and anti‐SRBC antibody titres determined 10 d after challenge were also higher in Bedouin hens than in White Leghorns.

4. We concluded that the Bedouin hens were less stressed by the cold than were the White Leghorn hens.  相似文献