共查询到20条相似文献，搜索用时 31 毫秒
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1. A mechanistic, stochastic egg production model is presented. Mean age at first egg may be predicted from the lighting programme applied during rearing, using the Bristol-Reading model (Lewis et al., 2002). 2. Rate of ovulation is determined by an amended version of the mathematical model of the ovulatory cycle, originally proposed by Etches and Schoch (1984). 3. Oviposition times are estimated from ovulation times. 4. Yolk, albumen and shell weights are calculated using allometric functions. 5. The model predicts egg production of a theoretical flock of laying hens for a full laying year, including random occurrences of double-yolked and soft-shelled eggs and internal ovulations. 相似文献
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Yasuhiro UNO Shinya HOSAKA Hiroshi YAMAZAKI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2014,76(12):1647-1650
Cytochromes P450 (P450) are
important for not only drug metabolism and toxicity, but also biosynthesis and metabolism
of cholesterol and bile acids, and steroid synthesis. In cynomolgus macaques, widely used
in biomedical research, we have characterized P450 cDNAs, which were isolated as expressed
sequence tags of cynomolgus macaque liver. In this study, cynomolgus CYP7A1, CYP17A1,
CYP20A1, CYP27A1 and CYP51A1 cDNAs were characterized by sequence analysis, phylogenetic
analysis and tissue expression pattern. By sequence analysis, these five cynomolgus P450s
had high sequence identities (94–99%) to the human orthologs in amino acids. By
phylogenetic analysis, each cynomolgus P450 was more closely related to the human ortholog
as compared with the dog or rat ortholog. By quantitative polymerase chain reaction, among
the 10 tissue types, CYP7A1 and CYP17A1 mRNAs were preferentially expressed in liver and
adrenal gland, respectively. Cynomolgus CYP27A1 and CYP51A1 mRNAs were most abundantly
expressed in liver and testis, respectively. Cynomolgus CYP20A1 mRNA was expressed in all
the tissues, including brain and liver. Tissue expression patterns of each cynomolgus P450
were generally similar to that of the human ortholog. These results suggest the molecular
similarities of CYP7A1, CYP17A1, CYP20A1, CYP27A1 and CYP51A1 between cynomolgus macaques
and humans. 相似文献
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We have optimized the polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) technique to screen the most frequent variants (A1, A2, A3, and B) of the bovine beta-casein gene. Five partly overlapping PCR products (233, 234, 265, 466, and 498 bp) of Exon VII of the beta-casein gene that encompass the target point mutations were heat-denatured, separated on nondenaturing polyacrylamide gels, and silver-stained. Simultaneous detection of all variants in reference samples of known genotypes (A1A2, A2A2, A1A3, A1B, and A2B) was best achieved on 17% polyacrylamide (100:1 acrylamide:bis-acrylamide ratio) gels with the PCR product of 234 bp. These results were confirmed by sequencing the allele-specific SSCP bands directly excised from polyacrylamide gels. A population of 65 anonymous samples belonging to various breeds was then analyzed twice, without discrepancies in a blind trial. Routine beta-casein genotyping using PCR-SSCP is proposed as a cost-effective, fast, and sensitive technique. 相似文献
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J W Sagartz H J Hardenbrook 《Journal of the American Veterinary Medical Association》1971,158(5):619-622
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藜麦生物学特性及应用 总被引：11，自引：0，他引：11
藜麦(Chenopodium quinoa)为苋科藜亚科藜属一年生双子叶草本植物,起源于南美洲安第斯山脉,已有5 000多年的栽培历史。藜麦籽实富含蛋白质、氨基酸、不饱和脂肪酸、维生素、矿物质及膳食纤维,且低脂、低糖、零胆固醇,利用价值高,是未来最具潜力的作物之一。本文综合国内外相关研究,系统论述了藜麦的资源分布、生物学特性、抗逆生理特性、营养成分及栽培技术等,并阐述了藜麦产品开发应用、国内引种栽培技术的现状及存在的问题。建议开展藜麦种质资源和营养化学成分方面的研究,选育适合不同海拔地区种植的品种,充分挖掘营养价值,使其成为将来国民保健型植源性食物之一。 相似文献
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R. C. Hill K. Haynes K. C. Scott S. J. Tucker J. K. Levy P. C. Crawford 《Journal of animal physiology and animal nutrition》2008,92(2):220-220
Upper respiratory infection (URI) is an important cause of morbidity and mortality in shelter cats. Malnutrition, specifically vitamin A deficiency, has been associated with respiratory tract infections in humans in developing countries. The purpose of this study was to determine whether feral cats and cats in shelters have lower serum vitamin A concentrations than pet cats, because it was surmised that a vitamin A deficiency may predispose these cats to develop URI. This was a cross-sectional study in which serum retinol, α-tocopherol, γ-tocopherol and beta carotene concentrations were measured from 48 shelter cats, 56 feral cats, and 42 pet cats, using HPLC. Retinol, α-tocopherol, and γ-tocopherol concentrations were found to be significantly lower in the shelter and feral cat populations than in pet cats (p ≤ 0.0001). There was no evidence of an effect of sex or neuter status on vitamin concentrations. Sick feral cats had a higher beta carotene level than did healthy feral cats. Within shelter and feral populations, no other effect of health status was found. The lower mean serum retinol and tocopherol concentrations in the feral and shelter cat groups could be due to oxidative or other forms of stress, the amount of vitamin consumed, or combinations of these. Further studies are needed to determine whether supplementation of fat-soluble vitamins improves the health status of feral or shelter cats. 相似文献
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M L Swanepoel 《The Onderstepoort journal of veterinary research》1984,51(1):41-46
By using well-defined techniques under optimum conditions it is possible adequately to define the biochemical characteristics of typical A. seminis strains. A. seminis can be distinguished from Histophilus ovis on the latter's distinctive colony morphology, but it cannot be distinguished from Actinobacillus actinomycetem-comitans. These organisms, however, can be differentiated from Pasteurella haemolytica on serological grounds and the latter's greater pathogenicity for mice. It is appreciated, however, that intermediate forms occur which cannot as yet be satisfactorily allocated to any of the above-mentioned genera. 相似文献
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