Effect of ph and temperature on the activity of phytase products used in broiler nutrition

The activity of three commercial microbial phytase (Aspergillus oryzae, A. niger, and Saccharomyces cerevisae) products used in broiler nutrition was determined at different pH (2.0 to 9.0) and temperature (20 to 90°C) values. Enzymatic activity was determined according to the reaction of the phytase with its substrate (sodium phytate), in four replicates, and was expressed in units of phytase activity (FTU). A. oryzae phytase exhibited optimal activity at pH 4.0 and 40°C, but its absolute activity was the lowest of the three phytases evaluated. A. niger phytase exhibited maximal activity close to pH 5.0 and 45ºC, whereas S. cerevisae phytase presented its highest activity at pH close to 4.5 and temperatures ranging between 50 and 60°C. It was concluded that A. niger and S. cerevisae phytase products exhibited the highest absolute activities in vitro at pH and temperature values (pH lower than 5.0 and 41ºC) corresponding to the ideal physiological conditions of broilers, which would theoretically allow high hydrolysis rate of the phytate contained in the feed.

Eficácia e toxicidade do pó comercial de Hoodia gordonii (Masson) swet ex decne utilizado no tratamento da obesidade / Efficacy and toxicity of Hoodia gordonii commercial powder used to combat obesity

A obesidade é atualmente o principal problema de saúde em países desenvolvidos e em desenvolvimento. Diversos recursos terapêuticos têm sido empregados para o tratamento da obesidade destacando-se os fitoterápicos, consagrados pelo conhecimento popular. Nesse contexto, a planta Hoodia gordonii tem despertado atualmente grande interesse mundial, principalmente pelas recentes descobertas e comprovações científicas da inibição do apetite e da sede pelo glicosídeo ativo P57 isolado de espécies da planta. Apesar disso, tais efeitos ainda não foram avaliados e comprovados em amostras comerciais do pó de H. gordonii (PHG), não existindo evidências científicas que garantam a sua eficácia e segurança. Portanto, o objetivo deste trabalho foi realizar ensaios biológicos com ratos para avaliar a atividade farmacológica e a toxicidade de amostras comerciais do pó de H. gordonii. As amostras foram administradas por gavagem em doses equivalentes a 20 vezes as recomendadas para humanos em ratas Wistar durante 4 semanas sendo avaliados os parâmetros indicadores do efeito terapêutico. Após as 4 semanas, os animais foram sacrificados, e amostras de sangue e órgãos foram coletados e submetidos à avaliação dos indicadores metabólicos, endócrinos, hematológicos e histopatológicos. Os resultados demonstraram que para todos os parâmetros avaliados não houve diferenças significativas entre o grupo controle que recebeu somente solução salina estéril e os grupos tratados com PHG indicando que os mesmos, apesar de não apresentarem quaisquer indícios de toxicidade, são incapazes de produzir os supostos efeitos de inibição de apetite e consequente tratamento da obesidade.

Obesity is currently the main health problem in developed and developing countries. Several therapeutic methods have been employed for the treatment of obesity, especially herbal medicines, highlighted by popular knowledge. In this context, the plant Hoodia gordonii has currently aroused great interest worldwide, especially for recent discoveries and scientific proof of inhibition of appetite and thirst by the active glycoside P57 isolated from plant species. Nevertheless, such effects have not been evaluated and proven for commercial samples of H. gordonii powder (PHG), with no scientific evidence to ensure its effectiveness and safety. Therefore, the aim of this study was to conduct biological tests with rats to evaluate the pharmacological activity and toxicity of commercial samples of H. gordonii powder. The samples were administered through gavage, at doses equivalent to 20 times those recommended for humans, in female Wistar rats during 4 weeks for evaluation of the parameters indicative of therapeutic efficacy. After 4 weeks, the animals were sacrificed and blood and organ samples were collected and subjected to the evaluation of metabolic, endocrine, hematological and histopathological indicators. Results showed that for all evaluated parameters, there were no significant differences between the control group that only received sterile saline solution and the groups treated with PHG, indicating that the latter, although presenting no evidence of toxicity, are unable to produce the alleged effects of appetite inhibition and subsequent obesity treatment.

Avaliação preliminar in vivo do efeito hipocolesterolêmico do polvilho da fruta-de-lobo (Solanum lycocarpum A. St.-Hil. ) / Preliminary evaluation of in vivo hypocholesterolemic effect of the flour of fruit-of-wolf (Solanum lycocarpum A. St.-Hil. )

O polvilho da fruta-de-lobo é um produto extraído da polpa da fruta-de-lobo verde (Solanum lycocarpum A. St.-Hil.), popularmente utilizado. Pouco se conhece a respeito desse polvilho, mas são atribuídos a ele vários efeitos terapêuticos, dentre eles a redução do colesterol. Este trabalho teve o objetivo de verificar a ação da administração do polvilho da fruta-de-lobo sobre animais hipercolesterolêmico. Utilizou-se 24 ratos Wistar fêmeas distribuídas em delineamento ao acaso, em três grupos contendo 8 animais em cada grupo. Estes grupos foram definidos como: controle normal (CN), controle hipocolesterolêmico (CH) e hipocolesterolêmico tratado (HT). O grupo CN recebeu dieta comercial, os grupo CH e HT receberam a dieta comercial enriquecida de colesterol e ácido cólico e o grupo HT recebeu também, 100 mg de polvilho da fruta-lobo, diariamente, por sonda orogástrica. O experimento teve uma duração de 6 semanas onde se avaliou o colesterol total sérico semanalmente, peso dos animais semanalmente e o consumo diário de ração. Ao término do experimento, foram avaliados os seguintes parâmetros: frações séricas de colesterol HDL, LDL+VLDL, peso do fígado, colesterol total hepático, lipídeos totais hepático e lâminas de microscopia foram feitas para avaliação dos hepatócitos. Não houve diferença significativa em relação ao peso corporal dos animais, ao consumo da dieta e nas análises de colesterol total sérico entre os grupos estudados. Avaliando-se a relação VLDL +LDL/HDL, os níveis encontrados no grupo HT foram significativamente menores que o grupo CH. Já em relação ao colesterol hepático, o grupo HT mostrou níveis menores de colesterol que o CH. Observou-se nos lipídeos hepáticos que não houve diferença significativa entre os grupo CH e HT, e no peso do fígado houve diferença significativa entre os grupos avaliados. Em relação à microscopia, os grupos hipercolesterolêmicos apresentaram discreta vacuolização no citoplasma dos hepatócitos. Concluiu-se, que o polvilho da fruta-de-lobo não influenciou o colesterol sérico dos animais, entretanto, reduziu os níveis de colesterol hepático.

The fruit-of-wolf flour is a product extracted from the pulp of green fruit-of-wolf (Solanum lycocarpum A. St .- Hil.) and is commonly used. Little is known about this flour, but several therapeutic effects, including cholesterol reduction, are attributed to it. This study aimed to verify the action of the administration of fruit-of-wolf flour to hypercholesterolemic animals. We used 24 female Wistar rats allocated in randomized design to three groups containing 8 animals each. These groups were defined as normal control (CN), hypocholesterolemic control (CH) and hypocholesterolemic treated rats (HT). The CN group received a commercial diet, while the CH and the HT group received the commercial diet enriched with cholesterol and cholic acid; the HT group also received 100 mg of fruit-of-wolf flour, daily, by orogastric tube. The experiment lasted for six weeks and the following characteristics were evaluated: weekly total serum cholesterol, weekly weight of animals and daily food intake. At the end of the experiment, we assessed the following parameters: serum cholesterol fractions HDL, LDL + VLDL, liver weight, liver total cholesterol, liver total lipids and microscopic slides were prepared for the evaluation of hepatocytes. There was no significant difference in body weight of animals, diet consumption and analysis of serum total cholesterol among the studied groups. Assessing the relationship VLDL + LDL / HDL, the levels found for the HT group were significantly lower than those for the CH group. As regards liver cholesterol, the HT group showed lower cholesterol levels than the CH group. For liver lipids there was no significant difference between the CH and the HT group, and for liver weight there was no significant difference among the studied groups. As to microscopy, the hypercholesterolemic groups showed slight vacuolization in the cytoplasm of hepatocytes. It was concluded that fruit-of-wolf flour did not influence the serum cholesterol of animals but reduced the levels of liver cholesterol.

Effect of ph and temperature on the activity of phytase products used in broiler nutrition

The activity of three commercial microbial phytase (Aspergillus oryzae, A. niger, and Saccharomyces cerevisae) products used in broiler nutrition was determined at different pH (2.0 to 9.0) and temperature (20 to 90°C) values. Enzymatic activity was determined according to the reaction of the phytase with its substrate (sodium phytate), in four replicates, and was expressed in units of phytase activity (FTU). A. oryzae phytase exhibited optimal activity at pH 4.0 and 40°C, but its absolute activity was the lowest of the three phytases evaluated. A. niger phytase exhibited maximal activity close to pH 5.0 and 45ºC, whereas S. cerevisae phytase presented its highest activity at pH close to 4.5 and temperatures ranging between 50 and 60°C. It was concluded that A. niger and S. cerevisae phytase products exhibited the highest absolute activities in vitro at pH and temperature values (pH lower than 5.0 and 41ºC) corresponding to the ideal physiological conditions of broilers, which would theoretically allow high hydrolysis rate of the phytate contained in the feed.