The influence of the regional basic diet from northeast Brazil on health and nutritional conditions of mice infected with Schistosoma mansoni.

Protein nutritional status indicators were studied in weanling albino Swiss mice infected with S. mansoni and fed the Regional Basic Diet (RBD) from Northeast Brazil, a multideficient diet of low-protein content. Each mouse was infected percutaneously with 80 cercariae. The experiment lasted 63 days. The growth curve, food consumption, protein intake, weight gain, Protein Efficiency Ratio (PER) and Net Protein Ratio (NPR) were the parameters investigated. RBD-fed mice showed a marked weight loss, a lower food and protein intake, a slower body weight gain and lower rates of food protein utilization when compared to casein-fed animals. Differences between infected and non-infected mice were not consistent. The present results suggest that the effects of RBD-induced malnutrition on health and nutritional conditions of the mice are more severe than those of Manson's schistosomiasis, in the initial phase of the disease.

Nutrition and acute schistosomiasis.

In northeast Brazil, nutritional deficiency diseases and schistosomiasis mansoni overlap. An experimental model, which reproduces the marasmatic clinical form of protein-energy malnutrition, was developed in this laboratory to study these interactions. Albino Swiss mice were fed with a food association ingested usually by human populations in northeast Brazil. This diet (Regional Basic Diet - RBD) has negative effects on the growth, food intake and protein utilization in infected mice (acute phase of murine schistosomiasis). Nitrogen balance studies have also shown that infection with Schistosoma mansoni has apparently no effect on protein intestinal absorption in well nourished mice. However, the lowest absorption ratios have been detected among RBD--fed infected animals, suggesting that superimposed schistosome infection aggravated the nutritional status of the undernourished host. The serum proteins electrophoretic pattern, as far as albumins are concerned, is quite similar for non-infected undernourished and infected well-fed animals. So, the significance of albumins as a biochemical indicator of the nutritional status of human populations residing in endemic foci of Manson's schistosomiasis, is discussable.

Liver and serum soluble protein changes and pathomorphology in undernourished mice with acute schistosomiasis mansoni.

Body, liver and spleen weights; histopathology of the liver, spleen and intestines; hepatic and serum soluble proteins changes were the parameters studied in undernourished Swiss albino mice experimentally infected with S. mansoni. Non-infected deficient animals had lower liver/body weight and spleen/body weight ratios as compared to the controls (22.60% casein group). Infected mice showed higher values regardless the type of diet. Undernourished infected subgroup showed a persistent exudative periovular reaction in the liver. Soluble hepatic proteins content and serum protein fractions appeared to be lower in the deficient infected mice. A significant difference was detected in the gammaglobulin fraction between infected and non-infected animals fed the control diet with higher values for the former. Our data suggest that the effects of malnutrition, per se, are sometimes more detrimental to the host than those due to Manson's schistosomiasis.

[Bean and rice mixtures of high protein value (author's transl)]. / Misturas de feijão e arroz de alto valor protéico.

The optimum content of different rice (Oryza sativa) and bean (Vigna unguiculata L.) combinations was studied in Albino rats. The mixture containing 3 g of rice proteins, corresponding to 41g of rice "in natura", and 7 g of bean protein, corresponding to 59 g of bean "in natura", presented the highest protein efficiency ratio and the feed efficiency ratio. Since the limiting amino acid of this mixture was methionine, new assays using varying levels of this amino acid as a supplement were carried out. The PER of normal rats as well as the "plateau" value of previously protein depleted rats were highest when 0.2% methionine was added to the mixture. The net protein utilization (NPU) confirmed these findings. The values attained after the addition of other amino acids were not higher than those attained by the mixture containing 7 g of bean protein and 3 g of rice protein supplemented with 0.2% methionine. The PER and the NPU values came close to those of milk.

[Biological value of a soy-corn-wheat based noodle (macaroni) supplemented with lysine (author's transl)]. / Valor biológico de uma massa alimentícia (macarrão) à base de soja-milho-trigo suplementada com lisina

The biological value of a soy-corn-wheat based noodle (macaroni) prepared by the General Food Corporation was studied. The protein level of the noodle was of 20.5g%. Thirty-six Albino rats were used in this experimental. The animals were divided into sex groups of six animals each. The experimental groups were fed: a) cooked macaroni without lysine; and b) macaroni supplemented with increasing levels of L-lysine HCL. The control group received commercial casein. The protein level of the experimental diets was of 10g%. At the end of the fourth week of the experiment some rats showed a slight difference in the growth curve, specially the animals fed macaroni without lysine. However, statistical analysis did not show a significant difference. The protein efficiency ratio (PER) of the experimental groups was similar to that of the control group, but when the lysine level of the diets increased there was a corresponding increase in the PER. No significant difference was noted too. These results suggest that lysine do not improve the biological value of the noodle.

[Nutritive value of macaçar bean (Vigna unguiculatta L.) Walp (author's transl)]. / Valor nutritivo do feijão maccar

The biological value of dry and immature macaçar bean (Vigna unguiculatta L.) Walp, isolated or associated to manioc flour, was studied. Thirty-six male Albino rats, Wistar strain, aged 23 days, were divided into six groups and fed experimental and control (casein) diets for 28 days. The weight curve and the PER of the animals fed dry and immature macaçar bean either isolated or associated to manioc flour were lower than those of the casein group. The data lead to the conclusion that the macaçar bean is to be used as a food supplement only, due to its low biological value.