Intestinal absorption of iron and calcium from soy and cow's milk-based infant formulas in weanling rats pups / Absorção intestinal de ferro e cálcio de fórmulas infantis à base de leite de vaca e de soja em filhotes de ratos recém-desmamados

ABSTRACT Objective: This study aimed to compare the intestinal absorption of iron and calcium between soy-based and cow's milk-based infant formulas in weanling rats. Methods: Twenty male Wistar rats, twenty-one days old on the first day of weaning, were used in this experiment, divided in two Groups, one Group was fed soy protein-based infant formula the other, cow's milk protein-based infant formula. During the study period (ten consecutive days) the animals received food and water ad libitum. Hematocrit and hemoglobin were evaluated on the first, fifth, and tenth days by the Wintrobe and cyanomethemoglobin methods. Feces and urine were collected, beginning on the fifth day, for three consecutive days. On the tenth day, hepatic iron content was also analyzed. Hepatic iron as well as fecal and urinary iron and calcium analyses were performed using an atomic absorption spectrophotometer. At thirty-one days of age, the animals were anesthetized with ketamine and xylazine and sacrificed by exsanguination via the vena cava. Results: The final concentration of hemoglobin in the group soy-based infant formula and milk-based infant formula were: 10.3±1.3g/dL and 10.9±1.0g/dL (p=0.310). The apparent absorption of iron and calcium, in that order, were: 73.4±10.2% and 70.2±9.5%; 97.2±0.7% and 97.6±1.0% (p=0.501; p=0.290). The apparent calcium retention was: 88.4% ±2.2 and 88.6±2.6% (p=0.848). Hepatic iron content was: 522.0±121.1mg/g and 527.8±80.5mg/g (p=0.907) . Conclusion: Intestinal iron and calcium absorption from soy-based infant formula is similar to that from milk-based infant formula in weanling rats.

RESUMO Objetivo: Este estudo objetivou comparar a absorção intestinal de ferro e cálcio entre fórmulas infantis à base de leite de vaca e de soja em ratos recém-desmamados. Métodos: Vinte ratos machos Wistar, com 21 dias de vida e no primeiro dia do desmame foram utilizados neste experimento, divididos em dois grupos: um alimentado com fórmula infantil à base de proteína de soja e o outro com fórmula infantil à base de proteína do leite de vaca. Durante o período de estudo (10 dias consecutivos), os ratos receberam dieta e água ad libitum. Hematócrito e hemoglobina foram mensurados no primeiro, quinto e décimo dia pelo método de Wintrobe e da cianometaemoglobina. As fezes e a urina foram recolhidas a partir do quinto dia durante durante três dias consecutivos. No décimo dia, o conteúdo de ferro hepático também foi analisado. O conteúdo de ferro hepático e a análise de ferro e cálcio nas fezes e na urina foram realizados utilizando espectrofotômetro de absorção atômica. Aos 31 dias de vida, os animais foram anestesiados com ketamina e xilasina e sacrificados por exsanguinação da veia vaca. Resultados: A concentração final de hemoglobina no grupo fórmula infantil à base de soja e fórmula infantil à base de leite de vaca foram 10,3±1,3g/dL e 10,9± 1,0g/dL (p=0,310), respectivamente. A absorção aparente de ferro e cálcio foi de: 73,4±10,2% e 70,2±9,5%, para o primeiro grupo; e 97,2±0,7% e 97,6±1,0%, para o segundo (p=0,501; p=0,290). A retenção aparente de cálcio foi: 88,4±2,2% e 88,6±2,6% (p=0,848). O teor de ferro hepático foi: 522,0±121,1µg/g e 527,8±80,5µg/g (p=0,907), respectivamente. Conclusão: A absorção intestinal de ferro e cálcio da fórmula infantil à base de soja é similar à da fórmula infantil à base de leite em ratos recém-desmamados.

Effects of soy beverage and soy-based formula on growth, weight, and fecal moisture: experimental study in rats / Efeitos de bebida e de fórmula de soja no crescimento, peso e umidade fecal: estudo experimental em ratos

OBJECTIVE: To compare body growth, weight, and fecal moisture in recently weaned rats fed exclusively on infant soy formula and soy-based beverage. METHODS: Three similar groups were formed (n = 10/group) consisting of weanling Wistar rats, maintained in metabolic cages. One group was fed soy protein-based beverage, another with soy-based infant formula, and another with cow's milk infant formula (control group). Water and diet were offered ad libitum. Body weight and length were measured. Stool was collected for three consecutive days. RESULTS: Weight and length were lower (p = 0.001; p = 0.001) in the groups receiving soy protein-based beverage (73.16 ± 5.74 g; 23.94 ± 1.04 cm) and soy-based formula (71.11 ± 5.84 g; 24.74 ± 0.60 cm) in relation to the group receiving cow's milk formula (84.88 ± 9.75 g; 26.01 ± 0.91 cm). Fresh fecal weight was greater (p < 0.001) in the soy-based beverage (3.44 ± 0.48 g) than in the soy-based formula (0.79 ± 0.20 g) and cow's milk-based formula (0.42 ± 0.17 g). Fecal moisture was higher (p < 0.001) in the group receiving soy protein-based beverage (47.28 ± 9.02%) and soy-based formula (37.21 ± 13.20%) than in the group receiving cow's milk formula (22.71 ± 10.86%). CONCLUSION: The growth of rats fed soy protein-based beverage and soy-based formula was lower than those fed cow's milk-based formula. The soy protein-based beverage resulted in significant increase in fecal weight and moisture. .

OBJETIVO: Comparar o crescimento corporal, o peso e a umidade das fezes de ratos recém-desmamados alimentados exclusivamente com fórmula infantil de soja e com bebida de extrato de soja. MÉTODOS: Constituíram-se três grupos similares (n = 10/grupo) de ratos machos Wistar recém-desmamados, mantidos em gaiolas metabólicas. Um grupo foi alimentado com bebida de extrato de soja, outro com fórmula infantil de soja e o outro com fórmula infantil de leite de vaca (grupo controle). Água e dieta foram oferecidas ad libitum. Foram mensurados o peso e o comprimento corporal. Fezes foram coletadas durante três dias consecutivos. RESULTADOS: Peso e comprimento foram menores (p = 0,001; p = 0,001) nos grupos com bebida de extrato de soja (73,16 ± 5,74 g; 23,94 ± 1,04 cm) e fórmula infantil de soja (71,11 ± 5,84 g; 24,74 ± 0,60 cm) em relação ao grupo de fórmula infantil de leite de vaca (84,88 ± 9,75 g; 26,01 ± 0,91 cm). O peso fresco fecal foi maior (p < 0,001) na bebida de extrato de soja (3,44 ± 0,48 g) do que com as fórmulas infantis de soja (0,79 ± 0,20 g) e de leite de vaca (0,42 ± 0,17 g). A umidade fecal foi maior (p < 0,001) na bebida de extrato de soja (47,28 ± 9,02%) e fórmula infantil de soja (37,21 ± 13,20%) do que na fórmula infantil de leite de vaca (22,71 ± 10,86%). CONCLUSÃO: O crescimento de ratos alimentados com bebida de soja e fórmula infantil de soja foi menor do que os alimentados com fórmula com proteína do leite de vaca. A bebida à base de extrato de soja proporcionou aumento expressivo do peso e da umidade fecal. .

Determination of soy proteins in calabresa sausage by densitometry on gel electrophoresis

Soy proteins are widely employed in meat products. However addition of non-meat proteins in calabresa sausages is not allowed according to the Brazilian legislation and in case of the non-declared addition of this foreign protein in consumed food, it may trigger allergic reactions in some consumers. Polyacrylamide gel electrophoresis (SDS-PAGE) was used for determining soy proteins in calabresa sausages. Fraud simulations were performed adding different concentrations (0%; 0.5%; 1%; 2%; 5%;10%; 20% and 100%) of soy proteins in sausages. The qualitative analysis was not sensitive to detect thelo west concentrations of soy proteins. On the other hand, by using semi-quantitative analysis by means of densitometry of selected protein fractions from soy and porcine meat, the presence of soy proteins could be determined in the all of analyzed concentrations. This methodology could be implemented, without large investments, for conducting quality control of sausages.