Dieta hiperlipídica com farinha de soja como fonte proteica: utilização na seleção de ratos propensos e resistentes à obesidade

OBJETIVO: Desenvolver uma dieta hiperlipídica de baixo custo, tendo farinha de soja como fonte proteica, que seja eficiente na seleção de ratos propensos e resistentes à obesidade e que permita alcançar fenótipo obeso nos animais propensos. Além desses requisitos, a dieta deve ser palatável e não rejeitada a curto prazo pelo animal. MÉTODOS: A dieta proposta foi obtida misturando-se leite condensado (15,5%), amendoim (18,5%), farinha de soja (20,0%), óleo de milho (6,0%), ração Bio Tec (30,0%) e bolacha wafer de chocolate (10,0%). A mistura foi peletizada e submetida à análise bromatológica. A dieta foi ofertada a ratos Wistar durante uma semana; posteriormente, os animais foram divididos em três grupos, de acordo com o ganho de peso. O terço superior foi considerado propenso à obesidade e o terço inferior, resistente à obesidade. Após 80 dias de oferta da dieta, os animais foram sacrificados e foram quantificados o peso corpóreo, consumo alimentar, gorduras retroperitoneal, periepididimal, de carcaça e gorduras totais. RESULTADOS: Verificou-se que a dieta apresentava 5,31kcal/g, com a seguinte composição: 22,3% de gordura, 22,2% de proteína, 15,9% de fibra, estimando-se 35,7% de carboidrato. Ratos propensos à obesidade, alimentados por 87 dias com a dieta hipercalórica, apresentaram peso corpóreo, gorduras retroperitoneal, periepididimal e totais significativamente maiores do que animais resistentes à obesidade (p<0,05). O consumo de alimentos também foi maior em animais propensos (p<0,05). Verificou-se também que a substituição da caseína pela farinha de soja, como componente proteico da ração, levou à diminuição de 96,0% no custo do estudo. CONCLUSÃO: A dieta formulada com farinha de soja apresentou custo reduzido e foi capaz de desenvolver o fenótipo obeso em ratos propensos, à semelhança do observado na literatura com outras dietas.OBJECTIVE: The objective was to develop a high-fat, low cost diet, using soybean meal as protein source. This diet should effectively discriminate between rats prone and resistant to obesity and allow the obese phenotype to be achieved in the animals that are prone to obesity. Furthermore, the diet must be palatable and not be rejected by the animal in the short run. METHODS: The chow was obtained by mixing the following ingredients: condensed milk (15.5%), peanuts (18.5%), soybean meal (20.0%), corn oil (6.0%), Bio Tec chow (30.0%) and chocolate wafer cookies (10.0%). In order to make it appropriate for rats, the mixture was pelleted and subjected to food analysis. The chow was offered to Wistar rats for a week. The animals were subsequently separated according to weight gained. The upper third group was considered prone to obesity and the lower third group was considered resistant to obesity. The animals were sacrificed 80 days later to determine body weight, food intake, retroperitoneal, periepididymal and carcass fats and total fats. RESULTS: Food analysis found that the chow had an energy density of 5.31 Kcal/g, 22.3% fat, 22.2% protein, 15.9% fiber and 35.7% carbohydrates. After being fed for 87 days with the high-fat diet, obesity-prone rats had higher body weight and retroperitoneal, periepididymal and total fats than obesity-resistant animals (p<0.05). Food intake was also higher among obesity-prone rats (p<0.05). The replacement of casein by soybean meal as protein source reduced the cost of the study by 96.0%. CONCLUSION: The substitution of casein by soybean meal in a high-fat diet allows cost reduction and the identification of obese-prone rats. Continuous use of this high-fat diet resulted in the development of the obese phenotype, as seen with other diets used in the literature

Uso de maltodextrina e prebiótico em rações de leitões desmamados

Two experiments were conducted to evaluate the effect of replacing lactose with maltodextrin and adding fructooligosaccharides (FOSs) to the feed of weaned piglets. The first experiment was conducted using a randomized block design with a 2 x 2 factorial arrangement (2 sources of carbohydrates: maltodextrin and lactose in the pre-starter feed and with or without the use of 0.3% FOS in the pre-starter and starter feeds) with 7 repetitions in 3 animals. Performance and hematological parameters were evaluated. The second experiment was conducted using a randomized block design with a 2 x 2 x 2 + 1 factorial arrangement (2 sources of carbohydrates: maltodextrin and lactose and with or without the use of 0.3% FOS; 2 slaughter dates: 7 and 14 d post-weaning; and slaughter on the day of weaning) with 8 repetitions in 1 animal. The following parameters were evaluated: pH and relative weight of digestive organs, enzyme activity, and microbial population. In the initial phase, maltodextrin did not compromise performance and could replace lactose with economic benefits; however, it does reduce intake of the pre-starter I feed. Maltodextrin has a prebiotic effect because it reduces the total coliform and E. coli populations in the cecum and reduces the pH of the rectal contents. The use of FOSs is not justified, regardless of whether lactose or maltodextrin is added to the feed.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP