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Human scabies of wombat origin   总被引:2,自引:0,他引:2  
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The present paper explores the relationships between aquaculture and the environment In Asia, focusing on the demands for environmental goods and services among different sectors. Aquaculture in the region accounts for 88% of global production by weight and 80% by value. Nevertheless, environmental problems are increasingly apparent and the higher the demands for environmental goods and services, the more negative the impacts. Against a background of rapid social, economic and political change, the paper considers how the sustainability of the industry is best assured. An integrated view of resource use, in which aquaculture is but one activity, is necessary for sustainable development. The roles of planning, education, research and environmental management schemes are discussed.  相似文献   
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The effects of feeding time and frequency on the growth, feed utilization and survival of Clarias gariepinus (Burchell 1822; family Clariidae) fingerlings were evaluated in a 25-day study. Groups of African catfish with an initial individual weight of 0.98 ± 0.02 g were offered feeds continuously for 24 h, or during the day or night at different time intervals, with varying meal size. The growth rate was significantly affected by meal times. Widely practised day time feeding with three equal size meals a day gave the lowest growth and highest food wastage. The growth rates of fish fed continuously or during night time following their feed demand were significantly higher with lowest food conversion ratios and food wastage.  相似文献   
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Bookshelf     
Exotic Diseases of Animals: a field guide for Australian veterinarians , Geering WA, Forman AJ and Nunn MJ
Student's Guide to Bovine Clinics , 2nd edition, C Pasquini & S Pasquini  相似文献   
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Groups of six worm-free merino lambs were infected with 100,000 larvae of T. colubriformis, T. vitrinus, T. rugatus or a mixture of the three species and were slaughtered 21 days later. Nematodes were distributed predominantly in the first 3 m of the small intestine where they caused subtotal villus atrophy. T. vitrinus caused severe erosion of the epithelium; erosion was less severe with T. colubriformis infections and mild with T. rugatus infections. Plasma concentrations of albumin declined during the experiment and were most marked in sheep infected with T. vitrinus. Plasma phosphate concentrations declined during infection with all three species, while plasma concentrations of globulin and calcium declined only in sheep infected with T. vitrinus. Food intake was reduced in all groups, but was most marked with sheep infected with T. vitrinus. T. vitrinus appeared to be more pathogenic than the other species.  相似文献   
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Four groups of six 5-month-old merino lambs were exposed to infection with 12,000 larvae of Trichostrongylus rugatus per week and one group was killed at each of 3, 6, 9 and 12 weeks. Numbers of adult worms increased in an approximately linear manner throughout the experiment; the percentage of larvae developing to adults remained between 35 and 25% throughout the course of the experiment. Sub-total villus atrophy was evident in the anterior small intestine of each group of infected sheep and significant reductions occurred in the plasma concentrations of albumin and phosphate. Serum globulin and calcium concentrations rose in infected animals. No clinical signs were observed in infected sheep, no alteration in bone histology was detected and no decrease in growth rate occurred.  相似文献   
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