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New techniques involving extraction with organic solvents and lithium carbonate solution have been used to fractionate nitrogenous components of the excreta from laying hens fed diets in which the supplementary protein was groundnut meal, poor‐quality fish meal or good‐quality fish meal. The effect of adding methionine or lysine or both to the groundnut diet was also studied.

The proportion of ingested nitrogen excreted as uric acid or urate was significantly higher when the dietary protein supplement was groundnut meal than when it was good‐quality fish meal or groundnut meal supplemented with both lysine and methionine. Nitrogen retention, egg production and the apparent digestibility of nitrogen were higher on diets containing good‐quality fish meal than on diets containing groundnut meal alone. Intermediate effects were obtained when feeding diets supplemented with poor‐quality fish meal of groundnut meal containing either lysine or methionine. The implications of these findings are discussed. The main differences in protein utilisation associated with variations in dietary protein quality were reflected in the proportions of ingested nitrogen excreted as urates and as protein. Other nitrogenous components of excreta examined showed little variation with dietary protein quality. Benefits derived from the addition of methionine and lysine to the groundnut diet were obtained mainly by a more efficient use of absorbed amino acids.  相似文献   

94.
Using a hand-held optical fiber, a surgical neodymium:yttrium, aluminum, and garnet laser was used transsclerally on the left ciliary body of 25 dogs. Dogs were assigned to groups and were given low (100 J) and high (238 J) energy levels. In 12 dogs given 100-J energy, the intraocular pressure decreased a mean value of 6 mm of Hg below that in the untreated right eye. However, intraocular pressure returned to the pretreatment value 1 week after treatment. Intraocular lesions were not found by histologic examination 28 days later. In the second group of 13 dogs treated with 238-J energy, 6 were euthanatized 7 days after treatment and 7 were euthanatized 28 days after treatment. A mean decrease in intraocular pressure of 10 mm of Hg in the treated left eye, relative to the untreated right eye, persisted throughout the evaluation period. In eyes examined histologically 7 days after treatment, ciliary hemorrhage and necrosis were prominent. Other histologic changes were minimal and consisted principally of iris stromal hemorrhage. Of 7 dogs examined for 28 days after treatment, 6 remained sighted; in 1 dog, extensive intraocular hemorrhage occurred, eventually resulting in phthisis bulbi. Ciliary atrophy and fibrosis were the important histologic lesions observed 28 days after treatment. Laser energy delivered transsclerally by this optical system effectively induced ciliary necrosis and may be an effective treatment for canine glaucoma.  相似文献   
95.
The factors affecting photochemical production of radicals, the reaction of these radicals with oxygen, the factors affecting the formation of singlet oxygen and superoxide anions and the reactivity of these species are discussed. The effect of the medium upon the course of photo-oxidation reactions and methods for investigating the mechanisms of these reactions are summarised.  相似文献   
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Book reviews     
High Energy Diets for Poultry by W. O. Brown. U.S. Feed Grains Council: London, 1964. 48 pp.

The Nutrient Requirements of Farm Livestock. No. 1, Poultry: Summary of Recommendations. 50 pp. Agricultural Research Council, H.M.S.O., London, 1963. Price 2/6.  相似文献   

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