[Intestinal alterations and reduction of growth in prepuberal rats fed with soybean]. / Alteraciones intestinales y disminución del crecimiento en ratas prepúberes alimentadas con soja.

Weanling rats from the inbred lines alpha and beta were fed with a soybean-cereal mixture used for human consumption (AN). A group fed with laboratory rat chow was used as reference (AC). Growth and other nutritional parameters as well as intestinal morphohystometry were evaluated from 22 to 44 days of age. Growth rate and final weight were greater with AC in both lines of rats. The greater initial food conversion efficiency of AN diet, compared to AC, decreased rapidly with the progression of age, particularly in the beta strain. Nitrogen (N) and lipid fecal contents were significantly larger for AN in both lines. Apparent nitrogen digestibility, expressed as the difference between N intake and fecal N with respect to N intake was AC < AN (p < 0.01) for line alpha and AC > AN (p < 0.01) for line beta. The weight and the mucosal total width of the small intestine were AC > AN in both lines. AN produced a significant decrease of villi goblet cells in both strains (p < 0.005). Cecum weight was AC > AN (p < 0.01) for the beta strain. These results alert about uncontrolled consumption of soybean products without adequate inhibition of antinutritional factors, a potential risk for growing animal populations.

Alteraciones intestinales y disminución del crecimiento en ratas prepúberes alimentadas con soja. / [Intestinal alterations and reduction of growth in prepuberal rats fed with soybean]

Weanling rats from the inbred lines alpha and beta were fed with a soybean-cereal mixture used for human consumption (AN). A group fed with laboratory rat chow was used as reference (AC). Growth and other nutritional parameters as well as intestinal morphohystometry were evaluated from 22 to 44 days of age. Growth rate and final weight were greater with AC in both lines of rats. The greater initial food conversion efficiency of AN diet, compared to AC, decreased rapidly with the progression of age, particularly in the beta strain. Nitrogen (N) and lipid fecal contents were significantly larger for AN in both lines. Apparent nitrogen digestibility, expressed as the difference between N intake and fecal N with respect to N intake was AC < AN (p < 0.01) for line alpha and AC > AN (p < 0.01) for line beta. The weight and the mucosal total width of the small intestine were AC > AN in both lines. AN produced a significant decrease of villi goblet cells in both strains (p < 0.005). Cecum weight was AC > AN (p < 0.01) for the beta strain. These results alert about uncontrolled consumption of soybean products without adequate inhibition of antinutritional factors, a potential risk for growing animal populations.

Energy balance through age-related diurnal body weight variations in genetic obese and nonobese rats.

Indirect evidence of energy balance in laboratory rats is provided through the study of diurnal body weight variations in two inbred lines: obese beta and nonobese alpha, from birth to 200-300 days of age, with different feeding patterns from 25 to 75 days of age. Nocturnal weight gain (NWG) was the gain recorded after the dark phase, in direct relation to the acquisition of exogenous calories in excess of the current metabolic expenditure at nighttime. Daytime weight variation was either weight gain during lactation (DWG) or weight loss from weaning onwards (DWL), recorded after the light phase. DWL is in direct relation to daytime energy output, when metabolic expenditure exceeds the low rate of acquisition of exogenous calories. The correlation between averaged individual DWL and NWG absolute values was highly significant at every age studied. An increase in absolute DWL values with age was observed and at adulthood DWL was compensated for equivalent NWG. This increasing energy output with age during daytime, is most likely related to the maintenance of increasing biomass and consequently, to progressive reduced growth energy availability. The existence of energy homeostasis and ponderostat with set points genetically prescribed in adults, is suggested. Significant differences between lines found before adulthood give indirect evidence of higher fat accretion in the obese line in those periods of intense growth, known as the active phase of obesity.

[Chemical and nutritional assessment of a soybean and cereal mixture for adults]. / Evaluación química y nutricional de un alimento para adultos a base de soja y cereales.

Legume seeds and fibre rich plant foods usually improve aspects of human diabetes control as they are potential sources of "delayed release" carbohydrates. A regional bakery mixture of soybean and cereals, interesting for its palatability and high content in non starch polysaccharides was chemically and nutritionally evaluated. Comparisons were made with the usual commercial laboratory chow and with a cafeteria mixture. Each one of the three diets was offered ad libitum to adult rats of line IIMb/Fm beta (beta), affected by obesity, hypertriglyceridemia and glucose intolerance or diabetes. Treatments lasted three months and were performed on two groups of male rats: (a) From 100 days old growing significantly. (b) From 200 days old. Meals had similar carbohydrate and calorie contents but acid followed by enzymatica hydrolysis was required to free monosaccharides from the soybean mixture. Cafeteria mixture lacked in fibre, was rich in saturated fats and sodium, and it caused hyperphagia. Each group of rats showed similar food intakes in both ages although weight gain was significantly higher in the younger animals. In the latter, values of glycemic response showed no difference between diets. Cafeteria mixture caused significant hyperglycemia to the elder rats, while the soybean bakery mixture produced a remarkably lower glycemic response; in one case it was even lower than the one produced by the commercial chow. Differential response showed more clearly with age. The results of the feces analysis demonstrated an increased proportion of fecal water for the bakery mixture group, probably due to the amount of undigestible fibre, inducing beneficial effects on large bowel functionality.

[Peripuberal development of genetic obesity in beta rats. Daily changes in food intake, body weight, deep body temperature, triglyceridemia and glycemia]. / Desarrollo peripuberal de la obesidad genética en ratas beta (beta). Variaciones diarias de ingestión, peso, temperatura corporal profunda, trigliceridemia y glucemia.

The moderate quality of beta obesity and its relatively slow evolution make it potentially useful for defining the sequence of events that lead to the overt syndrome. Estimates of food intake, live body weight, deep body temperature, triglyceridemia and glycemia were obtained at several times during the day in beta genetically obese and alpha (alpha) control male rats at peripuberal age, in order to characterize the dynamic phase of this obesity and to attempt the definition of some previous proceedings that eventually produce the full obesity syndrome. Beta higher food intake in the light cycle preceded its whole day hyperphagia. Both genotypes showed the normal pattern of predominantly nocturnal feeding. A lower light phase's weight loss in beta preceded the overweight. Thus, beta rats were not significantly heavier than alpha until the end of the last period studied, when they were 75 days old. A defect in adaptive thermogenesis in beta genotype is suggested, as values on deep body temperature in relation to alpha were significantly lower at all times of day tested. Correlation coefficient value between daily net weight gain versus deep body temperature was: r = -0.601 (p less than 0.01), suggesting a diminished lipolytic stimulation in beta brown adipose tissue. A sustained hypertriglyceridemia in beta at every time of the day studied suggested its endogenous source. Differences in glycemia values were not statistically significant between genotypes, though apparently wider variations in beta could reflect a certain glycemic regulation lability in the obese genotype.

Desarrollo peripuberal de la obesidad genética en ratas beta (beta). Variaciones diarias de ingestión, peso, temperatura corporal profunda, trigliceridemia y glucemia. / [Peripuberal development of genetic obesity in beta rats. Daily changes in food intake, body weight, deep body temperature, triglyceridemia and glycemia]

The moderate quality of beta obesity and its relatively slow evolution make it potentially useful for defining the sequence of events that lead to the overt syndrome. Estimates of food intake, live body weight, deep body temperature, triglyceridemia and glycemia were obtained at several times during the day in beta genetically obese and alpha (alpha) control male rats at peripuberal age, in order to characterize the dynamic phase of this obesity and to attempt the definition of some previous proceedings that eventually produce the full obesity syndrome. Beta higher food intake in the light cycle preceded its whole day hyperphagia. Both genotypes showed the normal pattern of predominantly nocturnal feeding. A lower light phases weight loss in beta preceded the overweight. Thus, beta rats were not significantly heavier than alpha until the end of the last period studied, when they were 75 days old. A defect in adaptive thermogenesis in beta genotype is suggested, as values on deep body temperature in relation to alpha were significantly lower at all times of day tested. Correlation coefficient value between daily net weight gain versus deep body temperature was: r = -0.601 (p less than 0.01), suggesting a diminished lipolytic stimulation in beta brown adipose tissue. A sustained hypertriglyceridemia in beta at every time of the day studied suggested its endogenous source. Differences in glycemia values were not statistically significant between genotypes, though apparently wider variations in beta could reflect a certain glycemic regulation lability in the obese genotype.