Composition in fatty acids of mature milk of nursing mothers / Composição em ácidos graxos do leite maduro de nutrizes

Abstract Objectives: to determine the fatty acid composition of mature milk of nursing mothers and its distribution according to some maternal variables. Methods: this is a cross-sectional observational epidemiological study based on the eva-luation of the fatty acid profile of mature human milk. Samples of mature breast milk were taken from 106 nursing mothers, by manual milking and who were after the 5th postpartum week. The milk fat extraction was carried out by using the Bligh and Dyer method and methy-lated with 0.25 mol/L sodium methoxide in methanol diethyl ether. The fatty acid of the milk profile was determined by a Gas Chromatograph equipped with a flame ionization detector. Results: among the saturated fatty acids, the highest values were observed for palmitic (C16:0), stearic (C18:0), myristic (C14:0) and lauric (C12:0) fatty acids, respectively. Among the monounsaturated fatty acids, there was a higher contribution of oleic (C18:1) and palmi-toleic (C16:1) fatty acids, respectively. The total essential fatty acids (linoleic and α-linolenic) was 14.94%. Conclusions: a low content of essential fatty acids in the breast milk of the nursing mothers was observed in the present study, which are important for infant growth and deve-lopment. We suggest the need to implement nutrition education strategies aimed for pregnant women and nursing mothers who should be advised to eat healthier foods.

Resumo Objetivos: determinar a composição em ácidos graxos do leite maduro de nutrizes e sua distribuição segundo algumas variáveis maternas. Métodos: trata-se de um estudo epidemiológico observacional, transversal realizado a partir da avaliação do perfil de ácidos graxos do leite humano maduro. Amostras de leite materno maduro foram obtidas de 106 nutrizes, a partir da 5ª semana pós-parto, por meio de ordenha manual. A extração da gordura do leite foi realizada através do método de Bligh e Dyer, e metiladas com metóxido de sódio 0,25 mol/L em metanol dietil - éter. O perfil de ácidos graxos do leite foi determinado por um Cromatógrafo a Gás equipado com detector por ionização de chamas. Resultados: dentre os ácidos graxos saturados, foram observados valores mais elevados para os ácidos graxos palmítico (C16:0), esteárico (C18:0), mirístico (C14:0) e láurico (C12:0), respectivamente. Entre os ácidos graxos mono-insaturados, verificou-se maior contribuição dos ácidos graxos oleico (C18:1) e palmitoleico (C16:1), respectivamente. O total de ácidos graxos essenciais (linoleico e α- linolênico) foi de 14,94%. Conclusões: foi observado baixo teor de ácidos graxos essenciais no leite materno das nutrizes do presente estudo, que são importantes para o crescimento e desenvolvimento do lactente, sugerindo-se a necessidade de implementação de estratégias de educação nutricional direcionadas a gestantes e nutrizes que devem ser orientadas a consumir alimentos mais saudáveis.

Musk gland seasonal development and musk secretion are regulated by the testis in muskrat (Ondatra zibethicus)

BACKGROUND: The muskrat is a seasonal breeder. Males secrete musk to attract females during the breeding season. The testosterone binding to the androgen receptor (AR) in musk glands of muskrat may play an important role conducting the musk secretion process. METHODS: The musk gland, testis and blood samples of musk rats are collected in both breeding and non-breeding seasons. Some part of the samples are kept in liquid nitrogen for transcriptome analysis and Western blotting test. Some part of the samples are kept in 70% alcohol for histology experiment, blood samples are kept at -20 °C for the serum testosterone measurement experiment. RESULTS: This study demonstrates that the quantity of secreted musk, the volume of the musk glands, the diameter of the gland cells and AR expression are all higher during the breeding season than at other times (p < 0.01). StAR, P450scc and 3ß-HSD expression in the Leydig cells of the testis were also higher during this season, as was serum testosterone. AR was also observed in the gland cells of two other musk-secreting animals, the musk deer and small Indian civet, in their musk glands. These results suggest that the testes and musk glands co-develop seasonally. CONCLUSION: The musk glands' seasonal development and musk secretion are regulated by the testes, and testosterone plays an important role in the seasonal development of musk glands.

Perfil lipídico tecidual de ratos alimentados com diferentes fontes lipídicas / Tissue lipid profile of rats fed with different lipid sources

OBJETIVO:Determinar se fontes lipídicas com diferentes razões de ácidos graxos insaturados e saturados (PUFA+MUFA)/SFA na dieta altera o perfil lipídico tecidual, a concentração de lipídios (mg/g) dos tecidos hepáticos e mesentérico e a digestibilidade lipídica. MÉTODOS: Foi realizada cromatografia gasosa para determinar o perfil de ácidos graxos nos tecidos hepático e adiposo de ratos alimentados com diferentes fontes lipídicas. O coeficiente de digestibilidade foi determinado a partir da relação entre a quantidade de lipídios consumidos e a quantidade fecal excretada. RESULTADOS:Diferentes fontes lipídicas (óleo de soja, manteiga, margarina e gorduras de porco e de peixe) não alteraram o coeficiente de digestibilidade e o peso hepático, mas alteraram a deposição de lipídios em todos os tecidos adiposos estudados. Não foi possível fazer a correlação direta entre o perfil dietário dos ácidos graxos não essenciais e sua deposição nos tecidos estudados, visto que a lipogênese de novo impede a identificação dos ácidos graxos dietários. CONCLUSÃO:Não foi constatada uma relação direta entre o perfil dietário dos ácidos graxos e sua deposição nos tecidos estudados, exceto para os ácidos graxos trans e linoléico (C18:2) que não são sintetizados no rato. Esses ácidos graxos apresentaram uma concentração tecidual diretamente proporcional àquela das fontes dietárias. Quanto à razão (PUFA+MUFA)/SFA, encontrada no tecido hepático dos diferentes grupos, observa-se que esta foi diretamente proporcional aos valores apresentados pelas fontes lipídicas dietárias. Entretanto, essa associação não foi observada nos tecidos adiposos analisados.

OBJECTIVE:To determine if lipid sources with different unsaturated to saturated fatty acid ratios, (PUFA+MUFA)/SFA in the diet alter the lipid profile of tissues, the lipid concentration (mg/g) of the hepatic and mesenteric tissues and the lipid digestibility. METHODS:Gas chromatography was used to determine the profile of fatty acids in the hepatic and adipose tissues of rats fed with different lipid sources. The digestibility coefficient was determined based on the ratio between lipid intake and excreted in the feces. RESULTS:Different lipid sources (soy oil, butter, margarine and pig and fish fat) did not alter the digestibility coefficient and the hepatic weight, but they altered the lipid deposition in all adipose tissue evaluated. No direct correlation was observed between dietary non-essential fatty acid profile and its deposition in the studied adipose tissues, because of de novo which impedes the identification of the dietary fatty acid. CONCLUSION:A direct relationship was not verified between the dietary fatty acid profile and its deposition in the studied adipose tissues, except for the trans and linoleic (C18:2) fatty acids which are not synthesized in the rat. The tissue concentration of these fatty acids was directly proportional to their dietary sources. The (PUFA+MUFA)/SFA ratio found in the hepatic tissue of the different groups, was directly proportional to the values presented in the dietary lipid sources. However, this association was not observed in the adipose tissue.

Incorporation of dietary trans monounsaturated fatty acids into tissues of Walker 256 tumor-bearing rats

The correlation between dietary trans fatty acids and neoplasia was examined in the present study. Walker 256 tumor-bearing and control rats were fed a trans monounsaturated fatty acid (MUFA)-rich diet for 8 weeks and the incorporation of trans fatty acids by tumor tissue was examined. Also, the effect of tumor growth on trans fatty acid composition of plasma and liver, and the content of thiobarbituric acid-reactive substances (TBARS) was determined. Walker 256 tumor cells presented both trans and cis MUFAs given in the diet. The equivalent diet proportions were 0.66 for trans and 1.14 for cis. Taking into consideration the proportion of trans MUFAs in plasma (11.47 percent), the tumor incorporated these fatty acids in a more efficient manner (18.27 percent) than the liver (9.34 percent). Therefore, the dietary trans fatty acids present in the diet are actively incorporated by the tumor. Tumor growth itself caused marked changes in the proportion of polyunsaturated fatty acids in the plasma and liver but provoked only slight modifications in both trans and cis MUFAs. Tumor growth also reduced the unsaturation index in both plasma and liver, from 97.79 to 86.83 and from 77.51 to 69.64, respectively. This effect was partially related to an increase in the occurrence of the lipid oxidation/peroxidation process of TBARS content which was increased in both plasma (from 0.428 to 0.505) and liver (from 9.425 to 127.792) due to tumor growth

¿Mantequilla o margarina, cual es mejor para consumir?: implicancias para la nutrición y salud humana / Butter or margarine, which is better to consume?: implications for nutrition and human health

Las margarinas son productos industriales obtenidos al hidrogenar aceites vegetales y/o animales. Elaboradas como un sustituto de la mantequilla, actualmente se comercializan masivamente debido a que los procedimientos industriales que se utilizan en su fabricación permiten obtener productos parecidos a la mantequilla pero de menor costo y mayor duración. En el mercado están disponibles las llamadas margarinas de origen animal, constituidas principalmente por aceite de pescado hidrogenado o mezclas de este producto con aceite vegetal también hidrogenado; las margarinas vegetales constituidas sólo por aceite vegetal hidrogenado; las margarinas dietéticas que contienen hasta un 60 por ciento de agua (las standard contienen un 15-16 por ciento de agua), y las denominadas VTF (virtually trans free), esto es virtualmente libres de isómeros trans de ácidos grasos. No existe un consenso sobre el beneficio nutricional y de salud derivado del consumo de la mantequilla o de las diferentes margarinas, con relación a su aporte de ácidos grasos saturados (AGS), monoinsaturados (AGMI), poliinsaturados (AGPI), de tipo trans, colesterol, etc. En este trabajo se analiza comparativamente la composición de la mantequilla y de diferentes margarinas comercializadas en Chile con relación a su aporte nutricional. De los cuadros comparativos se puede deducir que el consumo de una margarina vegetal, o de una margarina vegetal tipo VTF aporta una cantidad de AGS mucho menor que la mantequilla y que las margarinas animales, y una mejor relación AGPI/AGS y AGMI+AGPI/AGS+trans. Es destacable, además, la ausencia de ácidos grasos trans en la margarina tipo VTF, ya que el consumo de este tipo de ácidos grasos se asocia a efectos potencialmente dañinos para la salud humana. Se concluye que el consumo de margarinas de origen vegetal sería más saludable que el consumo de mantequilla o margarinas de origen animal, en especial si la margarina vegetal corresponde al tipo VTF