Diamela Carías

Long-lasting effects of prenatal dietary choline availability on object recognition memory ability in adult rats

Abstract Choline is an essential nutrient required for early development. Previous studies have shown that prenatal choline availability influences adult memory abilities depending on the medial temporal lobe integrity. The relevance of prenatal choline availability on object recognition memory was assessed in adult Wistar rats. Three groups of pregnant Wistar rats were fed from E12 to E18 with choline-deficient (0 g/kg choline chloride), standard (1.1 g/kg choline chloride), or choline-supplemented (5 g/kg choline chloride) diets. The offspring was cross-fostered to rat dams fed a standard diet during pregnancy and tested at the age of 3 months in an object recognition memory task applying retention tests 24 and 48 hours after acquisition. Although no significant differences have been found in the performance of the three groups during the first retention test, the supplemented group exhibited improved memory compared with both the standard and the deficient group in the second retention test, 48 hours after acquisition. In addition, at the second retention test the deficient group did not differ from chance. Taken together, the results support the notion of a long-lasting beneficial effect of prenatal choline supplementation on object recognition memory which is evident when the rats reach adulthood. The results are discussed in terms of their relevance for improving the understanding of the cholinergic involvement in object recognition memory and the implications of the importance of maternal diet for lifelong cognitive abilities.

Choline dietary supplementation improves LiCl-induced context aversion retention in adult rats.

Previous studies have demonstrated that choline is an essential nutrient during prenatal and early postnatal developmental periods. Thus, the availability of choline during these periods produces some beneficial effects on hippocampal-dependent learning and memory in rats. However, research on the effect of adult choline supplementation on learning and memory abilities is scarce. In the present study, 3-4 month-old male Wistar rats receiving a 7-week choline-supplemented diet (4.5 fold that of a standard diet) and control rats receiving a standard diet were trained in a LiCl-induced contextual aversion task. Short and long-term context aversion retention was assessed by recording the consumption of a flavoured solution in the aversive and safe contexts over two subsequent tests. Statistical analysis showed that the supplemented group exhibited greater intake suppression in the aversive context than in the safe context when two retention tests were applied 3 and 15 days after conditioning. These results suggest that increasing dietary choline availability during adulthood may favour the retention of a context aversion.

Effect of food intake on protein quality measured in chicks by traditional or biochemical methods

Previous studies have shown that the activities of the hepatic enzymes xanthine dehydrogenase and nucleoside phosphorylase, as well as the uric acid excreted, can be used to determine the quality of the protein consumed in chickens, in a short time and using a small amount of the test protein. A common observation in protein quality evaluation is that the food intake of the control animals is considerably greater than that observed in those receiving proteins of low quality. Since this can affect the results, this study measured the quality of garbanzo bean and black bean proteins in chickens fed these beans ad libitum, feeding the bean diets at the level observed in the controls (soy protein+methionine) by enteral intubation or pair feeding the controls with the amount of food consumed by the chickens receiving the bean diets. In every case, protein quality was determined by protein efficiency ratio, net protein utilisation or the biochemical methods used in this study. The results showed that, when fed ad libitum, the animals assigned to the bean diets exhibited a lower food intake than the controls but, by tube feeding, food intake was made equal in both groups. Equal consumption, between these groups, was also obtained by reducing the amount of food offered to the controls to the levels measured in the groups assigned to the bean diets (pair feeding). These feeding strategies had a marked effect on growth, carcass protein content, protein catabolism and also in the results of protein quality. Thus, the control whose intake was reduced grew less, accumulated less protein in tissues and catabolised more of the protein consumed than the control fed ad libitum. In contrast, the chickens assigned to the bean diets, but whose food intake was increased by tube feeding, grew better, accumulated more protein in tissues and catabolised less protein. In general, the results of these experiments confirm the effectiveness of the biochemical methods for estimating protein quality and indicate that the protein quality of both garbanzo beans and black beans increased when it was measured at a food intake equivalent to that measured in the control animals. Since the overall purpose of this study was to evaluate techniques for protein quality determination meant to be applicable to humans nutrition rather than poultry nutrition, single proteins were used instead of combinations of proteins.

Nutritional evaluation of the soy-whey milk analogLa colina

The milk analogLa colina is a product which contains mainly whey, soy protein isolate and vegetable oil, designed for infants since one year, children, adolescents and adults of all ages. The concept behind this product is to offer an alternative to milk consumption which during the last decade has decreased dramatically in Venezuela mainly due to its high price and low availability. Accordingly, the purpose of this study was to evaluate nutritionally this new product in order to determine if from a nutritional stand point it could represent a valid alternative to milk consumption. The results showed thatLa Colina offers the same amount of protein, energy, vitamin A, calcium, phosphorus and potassium as whole milk powder and more sodium, iron and zinc. In addition, a rat assay showed that the energy in these two products is equally available and even though the proteins inLa colina are 3.9% less digestible, their quality determined by growth, PER or the nitrogen retained are excellent and identical to the quality of the proteins in milk. These results agreed with the theoretical chemical score of the proteins of this new product, which indicated that the amino acid profile of the mixture can fulfill the amino acid requirements of children, adolescents an adults. Both milk andLa colina are products with a high fat content. The fat in this new product however, is vegetable oil and therefore it has a more convenient fatty acid profile than whole milk and about one third of its cholesterol. In short, these results showed thatLa Colina from a nutritional point of view is an excellent alternative to milk consumption.