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甜菜碱对热应激肉鸡生产性能的影响 总被引：1，自引：0，他引：1
选用1日龄的肉仔鸡(麻鸡与隐性白的杂交一代)120只在常规状态下饲养至17日龄后进行试验。在试验期内,肉鸡被随机分成3组,并饲养在热应激环境中,对照组喂基础日粮,第 组、 组分别在基础日粮中添加0.1%、0.3%的甜菜碱。试验期内,定期测定采食量,增重等生产性能指标,81日龄时测定屠宰率。结果表明:在17～57日龄,与对照组相比较,第 组公鸡平均增重提高了278.9克/只,母鸡平均增重提高了218.7克/只,差异极显著(P<0.01)。与对照组相比较,第 组公鸡平均增重提高了0.2克/只、母鸡平均增重提高了17.6克/只,差异不显著(P>0.05);在采食量方面,对照组、第 组、第 组分别是:公鸡61.05克/只·日、66.12克/只·日、65.84克/只·日,母鸡46.68克/只·日、54.97克/只·日、53.59克/(只·日),三组差异不显著;与对照组相比较,第 组公鸡饲料转化率提高了0.5,差异显著(P<0.05);第 组母鸡饲料转化率提高了0.19,差异显著(P<0.05);与对照组相比较,第 组公鸡饲料转化率减少了0.22,差异显著(P<0.05);第 组母鸡饲料转化率减少了0.26,差异显著(P<0.05);对照组、第 组、第 组肉鸡的屠宰率分别是公鸡91.15%、90.90%、91.05%,母鸡91.70%、91.55%、91.85%,各组的屠宰率差异不显著(P>0.05)。结果证明,适量甜菜碱可以缓解热应激对肉鸡的不 相似文献
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D. DENT 《European Journal of Soil Science》1980,31(1):87-99
Proposals are made for horizon designation of soils developed under mangrove vegetation and in polders in northern New Zealand. A model is presented for predicting the development of acid sulphate soils by field survey prior to reclamation. 相似文献
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Abstract. Samples of Atlantic salmon, Salmo salar L., held in sea cages and tanks with running water were examined for presence of sea lice, Lepeophtheirus salmonis. The number of lice, their sex stage (only post-chalimus stages) and location on the fish body were recorded. A new method has been used to express parasitic intensity in fish of different size. Effects of different factors on the degree and character of infestation (structure of the lice population), such as fish size, habitat and chemical treatment, have been studied. Different lice categories have shown different susceptibility to delousing with dichlorvos. Second pre-adults are most susceptible, and males generally more than females. Running water has been found to'flush out'the lice from the fish body. Pre-adults are flushed out easier than adults, and males generally easier than females. Adult males show high tolerance to water of lowered salinity and great mobility manifested in occasional transfer between hosts. The higher activity level of adult males may partly explain a drop in proportion of males after delousing and in running water. Frequency of mating has been found to increase with parasitic intensity. 相似文献
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