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Ten male and 10 female rats from each of seven strains were fed a grain ration for 10 or 20 weeks from weaning. Body weight and body fat of these rats were compared with those of 20 rats of the same age and sex fed a ration containing 60% hydrogenated fat. Also, five male and five female rats of the same seven strains were killed at weaning. Mean weanling weights and the percentage of hody fat for the seven strains of rats were similar. Mean weights of five male rats fed grain for 20 weeks ranged from 304 g for S 5B/P1 rats to 445 g for Osborne-Mendel rats; for five female rats, mean weights ranged from 163 g for S 5B/P1 to 301 g for Osbornj-Mendel rats. Male rats fed the high fat ration ranged in weight from 346 g for S 5B/P1 to 693 g for Osborne-Mendel males. Females fed the high fat ration ranged in weight from 170 g for S 5B/P1 to 452 g for Osborne-Mendel rats. After 20 weeks of experiment (at 23 weeks of age), carcasses of both male and female rats fed grain contained from 10 (S 5B/P1) to 16% fat (Sprague-Dawley). Rats fed high fat ranged from 14 (S 5B/P1) to 40% (Osborne-Mendel) body fat. For rats of the same sex and age, body weight was influenced nearly equally by genetics (strain differences) and ration, but the percentage of body fat was influenced largely by the ration (74% of variation due to ration difference).

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Two groups of 10 healthy young men were matched on the basis of their free-choice consumptions of regular table salt. For 28 days they were then fed carefully controlled low-sodium foods. One group was permitted free-choice seasoning of these foods with regular table salt, the other with a 1:1 mixture of sodium and potassium chlorides. Intakes and urinary and fecal excretions of sodium and potassium were determined by analysis. The results were: 1) the subjects salted their food with essentially the same amounts of regular table salt as of the 1:1 mixture; 2) the sodium intake associated with seasoning at the table was reduced with the 1:1 mixture to 44 percent of the amount consumed with regular table salt; and 3) over a 28-day period there was no tendency for subjects to increase their use of a 1:1 mixture, when used in place of regular table salt, to compensate for their reduced sodium intakes. Under the conditions of this study, the use of the 1:1 mixture as a seasoning agent for foods that contained no added salt resulted in an average total intake of sodium (food plus seasoning) which was 55 percent that of the subjects using regular table salt.

SummaryThe design and analysis of an investigation of selection in simulated genetic populations is discussed. The long-range objectives and specification of parameters and models are outlined, and certain mechanics of simulation of genetic systems are included, Bome of which may be of general application to Monte Carlo investigations.The results from selection in small simulated populations under nine different models of gene action are discussed with respect to the effects of population size on inbreeding depression and the random drift of gene frequency.

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SummaryThis study utilizes a computer programme that simulates selection, linkage, and environmental variation in finite populations. The intensity or magnitude of those factors is related to the genetic progress of small simulated populations under nine genetic models, and the results are discussed in relation to existing theory.Populations with complete dominance, complementary factors, or duplicate factors were temporarily hindered in progress from selection by random drift, due to small population size, but the paucity of undesirable fixations indicates that the effect on total potential response should be negligible or small if selection is as intense as 1. Selection was effective in advancing the genetic mean of small populations under the models of gene action in which the genotype of highest merit is homozygous, but was weaker than random genetic drift when heterozygous genotypes were optimum. Little evidence was obtained to support Robertson's hypothesis that less intense selection may be optimum for reaching long·time selection goals.Differences in the amounts of simulated environmental variation between populations were important in affecting genetic progress only when the mean was changing rapidly because of intense selection. Genetic merit, gene frequency, and fixation essentially were unaffected by different levels of linkage, except in the first few generations of some populations. Linkage disequilibrium appears to bias estimates of components of genotypic variance for many generations in popu· lations selected for intermediates.

A process to reduce cholesterol in liquid egg yolk using P-cyclodextrin (CD) was optimized by response surface methodology, based on cholesterol reduction and yield. The most important factors influencing cholesterol reduction were dilution of egg yolk to a defined water:solid ratio and CD concentration. In the final process, egg yolk was adjusted to pH 10.5, diluted to a water:solid ratio of 2.9, heated to 5O"C, and CD added at a CD:cholesterol molar ratio of 4.0. The slurry was mixed for 6.5 min at 1800 rpm, cooled to 4°C and centrifuged. Cholesterol in the supematant was reduced by 89.2%. The yield, cholesterol and CD in the final product were adjusted by varying centrifugal force and CD concentration. brecht (1994), was marketed briefly in the U.S. This product was prepared by diluting egg yolk with a salt solution to dissociate and solubilize the granular fraction, followed by addition of CD. Insoluble CD-cholesterol complexes were removed by centrifugation and excess salt was removed by electrodialysis. That was a costly process, thus it might be economically advantageous to dissociate egg yolk granules by a different approach. Causeret et al. (1991) reported that egg yolk granules were dissociated at high and low pH. Our objective was to develop and optimize an efficient and simple process using CD to extract cholesterol from liquid egg yolk after dissociation of the granules by pH adjustment.