The response of adult rats to varying combinations of dietary lysine and threonine.

The response of adult rats fed diets containing amino acid mixtures with varying combinations of lysine and threonine was studied by estimating the change in body weights, organ weights, total nitrogen content of organs and the concentration of free plasma lysine and threonine. Analysis of variance indicates a significant effect of threonine, lysine and a significant interaction due to feeding the two amino acids on the body weights, organ weights and total nitrogen content of various organs. Significant effect on the level of the plasma free amino acid was also shown as a result of feeding the particular amino acid. Results show that in deficient animals the rates of building body protein are low but are higher in the lysine deficient animals than in the threonine deficient and protein deficient animals. The varying rates of exchanging protein between the various organs in response to changing the levels of amino acids in the diet would mean that total change in body protein or total nitrogen balance may not be satisfactory way to determine the protein or amino acid requirements for maintenance. It seems to be necessary to focus down on protein turnover rates in specific tissues.

Response of adult rats to lysine supplementation.

The response of adult rats to wheat flour protein fortified by addition of lysine was studied by utilizing the relative protein value (RPV) compared to non-fortified wheat flour. Lactalbumin was used as a standard protein. Fortification of wheat flour by 0.3% lysine resulted in better growth of rats when fed at 6% protein level. However, no significant difference was observed in the growth of rats fed non-fortified or fortified wheat flour at 4% or 2% protein level. The relative nutritive value (RNV) of supplemented wheat flour protein is higher than that of the non-supplemented when change in body weight or change in body water are used as response parameters. When the dietary protein is provided at maintenance or below maintenance levels, lysine is not limiting. Therefore, supplementation of wheat flour protein with lysine did not result in any better growth response. When protein is provided at levels above maintenance requirements lysine is limiting and better growth was achieved by lysine supplementation to wheat flour protein.

Development and evaluation of a colour-coded scale for birthweight surveillance in rural Egypt.

Birthweight surveillance is an important epidemiologic tool, yet it is largely unattainable in locales where most births occur at home attended by traditional midwives. A tempered-steel hand-held scale developed by Program for Appropriate Technology in Health (PATH, Seattle, USA) was adapted for use by Egyptian traditional midwives; it identified newborns weighing less than 2.5 kg by a colour code (yellow versus blue). The scale and reporting system were field tested in a rural Egyptian village. Traditional midwives reported 98% of 299 livebirths attended and 85% were reweighed by Salter scale within 48 hours. Sensitivity of the scale was 100%, specificity 94%. Field conditions are specified for incorporating this method into a surveillance system.

Effect of the drying process on the nutritive value of milk. Part 1. Biochemical composition.

Five different brands of instant dry whole milk that are most commonly used, and freeze dried milk were analyzed for nitrogen, fat, ash and 4 inorganic constituents and compared with human milk. The composition of the milks differed considerably. The protein content varied widely, ranging from 11.6 to 24.5%. Fat content did not differ widely, ranging from 24.9 to 29.5%. Freeze dried milk had the highest fat content (42.6%). Three out of the five brands of dry milk studied were spray dried and the remaining two were roller dried. All milks tested contained considerably more sodium, potassium, calcium and phosphorus solid than human milk, some of them the four fold amount of calcium and phosphorus.

Effect of the drying process on the nutritive value of milk. Part 2. Biological evaluation.

Five different brands of dry milk and freeze dried milk were used in rat feeding trials to study their nutritive value and to assess the effect of the drying process on their nutritive value by using growth response, weight gain, food efficiency and relative nutritive value (RNV). Brand I milk gave better growth response, weight gain and food efficiency than any other dry milk studied, while brand V gave the least values. Freeze dried milk gave better growth response, weight gain and food efficiency than brand I milk. Using Slope-ratio assay, freeze dried milk gave the best RNV compared to all dry milks tested on the basis of the two response parameters used, weight gain and moisture gain.

Nutritive value of meat-soy mixture.

The protein value of meat soy blend was evaluated by utilizing the net protein ratio (NPR), the relative protein value (RPV) and the serum urea content methods. It was compared with that of meat. Casein was used as a reference protein. NPR values indicated that utilization of meat and meat soy proteins are comparable. The study of amino acid pattern shows that sulphur containing amino acids are limiting to almost the same degree in meat and meat soy blend. However, the RPV of meat soy bean blend is slightly higher than that of meat. The lowest serum urea content was that of rats fed meat soy blend. Therefore, the mixing of meat with soy bean did not reduce the nutritive value of meat, on the contrary there is tendency towards improvement.

Nutritive value of some common Egyptian meals.

The protein quality of two common Egyptian meals namely lentils and "Koshari" was evaluated on rats by utilizing the net protein ratio (NPR), the relative protein value (RPV) and the serum urea content methods. Casein was used as a reference protein. The macro nutrient contents of the two meals are almost similar. The NPR is higher with low dietary protein level. The estimated RNV of the "Koshari" was higher than that of lentils. Lower serum urea levels were found with the "Koshari" than with lentils meal indicating its better protein quality. This is most probably due to the effect of amino acid supplementation of cereals and legumes. Results obtained are in favour of utilizing the serum urea content method as a simple and reliable one for evaluating protein quality since a negative relationship exists between blood urea content and the biological value of dietary protein. Its validity in estimating dietary protein quality in man need to be investigated.

The Egyptian National Nutrition Survey, 1978.

PIP: A national nutrition survey was conducted in Egypt during January-April 1978 in an effort to quantify the protein energy and anemia status of young children from rural and urban areas. Data from 9794 preschool children (8016 in the total representative sample and 1778 in metropolitan Cairo-Giza and Alexandria) were analyzed. Questionnaires on 106 additional children were excluded because of obvious errors in age or anthropometric data. The overall prevalence of wasting was low in all the areas studied. Stunting was identified in 20.8% of the representative sample children. The highest prevalences of stunting occurred in rural villages, small and large, particularly in Upper Egypt (27.0%). Linear growth improved, among the children studied, with increasing urbanization. In cities with a population greater than 50,000 (excluding Cairo and Alexandria), the prevalence of stunting was only 10.6%. The prevalence of stunting was 15.7% and 18.8% in the disadvantaged areas of Alexandria and Cairo-Giza, respectively, and only 1.1% in the special comparison group of 1883 socioeconomically advantaged children. Concurrent wasting and stunting was noted in 0.3% of the representative sample. Children in the 2 age groups between 6-23 months had the highest prevalence of acute undernutrition, and children aged 36-47 months had the highest prevalence of overnutrition. The prevalence of chronic undernutrition was highest in the 3 age groups between 12-47 months and declined approximately 16% in the 2 age groups between 48-71 months. The prevalence of severe malnutrition declined with urbanization from a high of 12.9% in small villages in Upper Egypt to 3.8% in the small cities. Among children in the disadvantaged areas of Alexandria and Cairo-Giza, the prevalences were 4.8% and 9.1%, respectively. For the representative sample, anemia was highest in the 3 age groups between 12-47 months. Of the 9794 children surveyed, 17 had edema in both feet. More than 1 clinical sign of vitamin D deficiency was found in 1.4% of children. Bitot's spots were found in only 4 children and corneal scars in 16.^ieng

Availability of essential amino acids in corn flour and corn bread.

The availability of nitrogen, lysine and 9 essential amino acids was determined in corn before and after baking. Lysine availability was determined by the growth response method on weaning rats using regression analysis of body weight gain or moisture gain against lysine consumed from corn flour and corn bread. The results show a high correlation between lysine consumed and weight gain or moisture gain (r = 0.95) for rats fed the standard diets for 3 weeks. A good correlation was also obtained for corn bread. The results of lysine availability show that baking greatly improves availability by both ways of calculation. The availability of nitrogen and essential amino acids were also investigated by the balance trials with rats. Results show that availability values for nitrogen and all amino acids except threonine increased by baking. Data for food intake, weight gain, food efficiency, PER, NPR and true digestibility revealed that baking had little or no effect on nutritive value of corn tested in this investigation.

The effect of baking on availability of essential amino acids in wheat.

Lysine availability in wheat flour and bread was determined by the growth response method on rats using regression analysis relating gain in body weight and/or in body water to lysine consumed at two extractions, 87% and 72%. The availability of nitrogen and of essential amino acids were also determined by the balance trials method (fecal analysis method) with rats. The results of growth method show that baking increases lysine availability on the basis of body water gain. Also extraction levels affect lysine availability on the basis of change in body water. Wheat flour and bread of 72% extraction has more lysine availability values than the 87% extraction on the basis of moisture gain. Results of balance trials show that neither the extraction level nor the baking has a significant effect on essential amino acids availability. A fairly good correlation is obtained for wheat flour and bread for the two extractions. Values of change in weight, food efficiency, PER, NPR and true digestibility showed that baking and level of extraction of wheat has no significant effect on the nutritive value of wheat investigated in the present study.

Supplementary and weaning foods for the Egyptian child.

Attempts were made to prepare 5 protein rich food mixtures to be used as supplementary and weaning foods for children from 6 months of age onwards. They contain vegetable and animal protein sources. They were prepared in a way to simplify their use. Potatoes, carrots and peas were the basal ingredient in each mixture. The protein content of the mixtures ranges from 16-20% with a chemical score not less than 50%. The mixtures contained most of the essential amino acids in optimal concentrations, except methionine and cystine which are slightly lower than the amounts recommended by FAO. The nutritive value of each mixture estimated by the slope ratio bioassay procedure was high. They are nutritionally superior to casein, used as a reference protein. They differ slightly when compared with each other.

Blood urea content for evaluating dietary protein quality.

The protein quality of broad beans was evaluated by using three different methods: the net protein ratio (NPR), the net protein utilization (NPU) and the relative protein value (RPV). Casein was used as a reference protein. The relationship between the values obtained on rats by each method and serum urea concentrations were examined. Serum urea concentration increased by increasing the dietary protein content. It showed a positive correlation of 0.70 and 0.60 for broad beans and casein respectively. NPR values increased by decreasing the level of dietary protein. There was no relationship between the NPR and the serum urea contents in animals fed the casein and broad bean diets. The NPU values indicated that protein utilization was greatest at low dietary protein levels and decreases by increasing the protein content of diet. Serum urea concentration showed an inverse proportion with the NPU values. This was demonstrated by correlations of -0.67 and -0.75 for broad beans and casein respectively. The highest RPV for broad beans was obtained by using the change in body water and the lowest by using the change in body nitrogen as a response parameter. An inverse relationship exists between serum urea concentration and the RPV for broad beans.