PubMed Health⌕ Search

Biomedical subjects

G R Jansen

Publications and source records attributed to G R Jansen.

At least 37 records · Page 2Linked to original sources
PubMed1984

Measurement of milk yield in the lactating rat from pup weight and weight gain.

A new method was developed that enables milk yield to be estimated from pup weight and pup weight gain in well-nourished rats. Daily milk yield, body weight, and daily weight gain were measured over 4-5-day periods in 38 suckling pups aged 3-13 days postpartum. Each 24-h period was divided into consecutive 6-h cycles, during which dams and pups were separated for 4 h and then reunited for 2-h suckling intervals. Daily milk yield per pup was calculated from pup weight gain during the four suckling intervals for each 24-h period, and corrected for insensible weight loss of the pups. The following equation, relating pup milk yield to pup weight and weight gain, was obtained by stepwise forward multiple regression analysis: yield = 0.0322 + 0.0667 (weight) + 0.877 (gain); where yield is daily yield per pup (g/pup/day), weight is pup weight (g), and gain is pup weight gain per day (g/day) (n = 174; F = 552.3; p less than 0.001; r2 = 0.866). Per litter milk yield can be obtained by multiplying per pup yield by litter size. Using this equation, dams fed a stock diet and nursing eight pups were estimated to have produced 29.5 ml of milk on day 10 of lactation. This value is similar to yields measured by more laborious methods. SEs of yield estimates calculated with this method represent 1-3% of predicted yield values. The new method gives useful estimates of rat milk yield during the first 2 weeks of lactation from measurements that are more easily obtained than is the case with other methods.

Animal Population Groups↗
PubMed1980

Application of low-cost extrusion cooking to weaning foods in feeding programmes. part 2.

A low-cost technology for making blended foods and oilseed flours has been developed within a programme operated by Colorado State University, USA. The technology is based on a low-cost extruder cooker (LEC). The primary products are 1) vitamin- and mineral-fortified cereal/legume blends for use in supplementary feeding programmes, and 2) protein supplements for fortifying cereal and/or root crop foods. Plants have been installed in four developing countries, and research and development activities are being carried out in a number of others. The programme involves agricultural and industrial development as well as nutritional improvement. The major product currently made is CSB, and in some cases CSM made by blending dried milk with CSB. These products have been demonstrated to be safe, nutritious and acceptable by the target population, although more work is needed on expanding the ways in which the blended foods might be used in traditional recipes, as well as in gruels and porridges.

Child, Preschool↗
PubMed1980

Alternate lunch patterns in high schools. I. Labor requirements and meal costs.

Meal costs were compared in forty-eight high schools as a function of the lunch pattern. The patterns evaluated were: Type A "offer vs. serve," traditional Type A, four food groups (Basic 4), and free choice. Participation in school lunch increased with free choice, resulting in a reduction in labor and total meal costs. Sixteen per cent of foodservice work involved administration, 37 per cent preparation, 16 per cent service, 25 per cent clean-up, and 6 per cent other, which did not vary with the menu pattern.

Adolescent↗
PubMed1980

Alternate lunch patterns in high schools. II. Student and foodstaff reactions.

Reactions to alternate menu patterns used in high school lunches were measured. Students rated food in Basic 4 and free-choice patterns more positively than Type A. The environment in the lunchroom was not rated differently with different menu patterns. Based on overall student reactions, the free-choice pattern was preferred. School lunch managers found the free-choice pattern more difficult to serve because of reimbursement and pricing problems but felt there was less plate waste and better student response with this system.

Administrative Personnel↗
PubMed1980

Alternate lunch patterns in high schools. III. Food acceptability.

Food acceptability was assessed in forty-eight high schools using alternate methods of menu planning for school lunches. The free-choice pattern resulted in a significant reduction of total plate waste, particularly in the vegetable and salad categories. Girls consistently wasted more food than did boys, regardless of menu pattern. Overall plate waste was 7 and 13 per cent of food service for boys and girls, respectively. The data suggest that a free-choice lunch may be effective in reducing plate waste, particularly for poorly consumed menu items.

Female↗
PubMed1980

Assessment of rat growth methods for estimating protein quality: interlaboratory study.

An interlaboratory study involving protein efficiency ratio (PER), net protein ratio (NPR), relative NPR (RNPR) and relative nitrogen utilization (RNU) was carried out. Six collaborators assayed 6 samples, including casein plus methionine which was used as a reference protein. Collaborators prepared their own diets and analyzed the diets for nitrogen. Test proteins were added at the 8% level (N X 6.25). PER values varied more than NPR values which varied more than either RNPR or RNU. RNU and RNPR produced almost identical values, but RNPR remains the official method of choice, because it is a well established method.

Animals↗
PubMed1980

Alternate lunch patterns in high schools. IV. Nutritive value.

The nutritive value of lunches in forty-eight high schools was assessed using alternate methods of menu planning. Using Type A, Basic 4, and free-choice patterns, the nutrient levels in lunches consumed were not significantly different from those of lunches using the Type A "offer vs. serve" pattern. For boys, lunches as consumed were significantly below the goals for calories, thiamin, and iron in all groups. For girls, lunches as consumed were significantly below the goal only for iron.

Adolescent↗
PubMed1978

Consumption and plate waste of menu items served in the National School Lunch Program.

Plate waste was determined in fifty-eight elementary and high schools in the USDA Western, Midwestern, and Southwestern Regions. By weighing sample trays and edible waste, the percentage of food served that was consumed was measured for 23,000 lunches. Highest consumption was recorded for milk, with 88 and 94 per cent consumed in the fifth and tenth grades respectively. Most entrées and starches were well consumed; vegetables and salads showed much less acceptability. Regional differences in food acceptability were minor, and high school students consistently wasted less food in all categories than did elementary pupils.

Adolescent↗
PubMed1977

Effect of income and geographic region on the nutritional value of diets in Brazil.

The nutritional quality of dietary patterns in Brazil was examined as influenced by income level, region, and urbanization by calculating nutrient to calorie ratios and amino acid scores. In general, income level had only a minor influence on diet quality. Riboflavin and calcium were generally low in the low income groups in all regions, especially in urban areas. Thiamin intake was marginal in urban areas at all income levels. Protein quality appeared to be relatively independent of income, with two exceptions. These were the dietary patterns of the lowest income groups in the rural Northeast and the City of Sao Paulo which were somewhat limiting in methionine and lysine, respectively. In contrast, the total availability of calories and protein was greatly dependent on income and the lowest income families were seriously short of food. Income, therefore, appeared to be more important in determining the total amount of food available to a family in Brazil than in affecting the nutritional quality of the diet.

Amino Acids↗
PubMed1977

Amino acid fortification of wheat diets fed at varying levels of energy intake to rats.

The effects on growth and nitrogen utilization of protein quality improvement of white bread fed under varying degrees of adequacy of food energy have been studied. Weanling rats were fed white bread bread plus lysine, and bread plus lysine plus threonine at energy levels ranging from 55% to 100% of ad libitum consumption. Weight gain, protein efficiency ratio (PER), net protein ratio (NPR), and net protein utilization (NPU) were measured and plotted against food consumption. The improvement in growth and nitrogen utilization resulting from amino acid fortification of bread, even when food intake was little more than half ad libitum consumption, was significant. For example, the NPR and NPU values obtained with lysine fortified bread fed at 70% of adlibitum consumption were 1.5 to 2 times those obtained with unfortified bread in spite of the fact that the latter rats consumed 25% more food energy. The implications of these findings for practical problems in human nutrition are discussed.

Animals↗
PubMed1977

Amino acid fortification of bread fed at varying levels during gestation and lactation in rats.

The effects of protein quality improvement of white bread fed to female rats during pregnancy and lactation, under varying degrees of adequacy in food energy, on growth and brain development of the offspring have been studied. Weaning weight and the weight, protein and DNA of whole brain and major regions of the brain at weaning were determined. Lysine addition significantly increased all parameters, and threonine addition gave additional significant increments. Restricting energy intake decreased most parameters independent of protein quality. Brain cellularity was significantly higher in offspring of dams fed lysine and threonine fortified bread than in offspring of dams fed casein. All parameters measured in the offspring of dams fed lysine and threonine fortified bread at 70% ad libitum consumption were significantly increased over the values obtained in the offspring of dams fed unfortified bread ad libitum even though they had consumed 13% less protein and dietary energy during the pregnancy and lactation period. The implications of these findings for practical problems in human nutrition are considered.

Animals↗
PubMed1976

Effect of feeding lysine and threonine fortified bread during gestation and lactation on growth of the offspring in rats.

White bread, bread fortified with lysine, or with lysine and threonine was fed to female rats as the sole source of protein (13% of diet) during two closely spaced gestation and lactation periods. Comparisons were made with diets containing 13% or 26% casein protein, and a stock diet. Weight changes and food consumption of the mothers were determined, as were birth weights and weaning weights of the offspring. Lysine fortification increased food consumption and decreased weight loss of the mothers during lactation. When threonine was added with the lysine, food consumption during lactation was further increased and maternal weight loss prevented. Average weaning weights for first litters as a function of diet were: bread 17.0 +/- 1.9 g, bread + lysine 26.8 +/- 1.0 g, bread + lysine + threonine 39.8 +/- 3.1 g, 13% casein 42.8 +/- 3.8 g, 26% casein 62.5 +/- 4.7 g, and stock diet 41.5 +/- 7.9 g. First and second litter weaning weights were closely similar for each. Although average birth weights were not greatly affected by dietary treatment, total offspring weight at birth of mothers fed unfortified bread was reduced 40% in the second, as compared to the first litter. This reduction in total offspring weight did not occur in mothers fed amino acid fortified bread.

Animals↗
PubMed1976

Effect of feeding lysine and threonine fortified bread during gestation and lactation on growth of the brain in rats.

First and second litter offspring brain development was studied following the feeding of bread, bread plus lysine, or bread plus lysine and threonine to rats during pregnancy and lactation. Results were compared with offspring brain growth following maternal consumption of a stock diet, 13% casein or 26% casein diet. Brain weight, protein and cellularity progressively increased as lysine and lysine plus threonine were added to the maternal bread diets. The bread plus lysine and threonine diet resulted in similar or higher total weight, protein and DNA values for all brain areas in comparison with results from the stock diet or 13% casein diet. The 26% casein diet resulted in greater brain weight, protein and DNA values in comparison to the bread, bread plus lysine, 13% casein, or stock diets. First litter pups whose mothers were fed the 26% casein diet, in comparison to the bread plus lysine and threonine diet, had higher or similar brain weight and DNA levels. For second litter pups, all values were similar for both diets with the exceptions of lower brain stem weight for 26% casein and lower cerebellum DNA for bread plus lysine and threonine.

Animals↗
PubMed1976

Menu planning in the Nutrition Program for the Elderly. Modified Nutrient Standard Menu method.

A nutrient standard menu (NSM) planning method was developed for use in planning menus which provided one-third the Recommended Dietary Allowances for persons sixty years of age or older for nine indicator nutrients and calories, while restricting fat to less than 40 per cent of total calories. To eliminate manual calculations and make it easy for individuals untrained in dietetics or nutrition to use NSM planning, the nutrient composition of over a thousand commonly used menu items was listed in a menu planning manual in nutrient units which were one-tenth of the nutrient standard for the meal. Menus from third-party sources were monitored by selecting similar nutritionally analyzed menu items in the manual and adjusting the nutrient composition to conform to the portions actually served. Ten site managers of the Administration on Aging (AoA) evaluated the planning/monitoring method. The members of the group, on the average, were fifty-six years of age, had 1.6 years of education beyond high school, and had 4.6 years of foodservice experience. Approximately 83 per cent of the evaluators did not plan to monitor menus at their sites and had no formal training in dietetics or nutrition. Eighty-four per cent were able to plan menus satisfactorily after this brief introduction. The younger evaluators with more education grasped the concepts faster and were able to plan menus with greater accuracy. The data also indicated that previous experience in menu planning enhanced their ability to plan NSMs. Most felt the approach to be workable and applicable. Menu monitoring was more difficult for the evaluators. Seventy-five per cent were able to monitor menus satisfactorily, and all felt they could do so with more time. The data again showed that the younger individuals having more formal education were able to master the monitoring skills more easily.

Adult↗
PubMed1975

Comparison of Type A and nutrient standard menus for school lunch. I. Development of the nutrient standard method (NSM).

Methodology was developed for planning school lunch menus which meet a specific nutrient standard. The method considered nine indicator nutrients plus calories and percentage of calories coming from fat. The nutrient composition of approximately 625 school lunch menu items were calculated using Agriculture Handbook No. 8 data. All nutrient data were converted to bead units which were summed on an abacus until the meal requirements were met. Preliminary testing of the method showed it to be usable by school lunch menu planners and provided menus meeting certain minimal nutrient constraints. After the test, suggested modifications were incorporated into the method to enhance its use. The method is described and a sample week's given.

Adolescent↗