A critical period for omega-3 nutritional supplementation in the development of the rodent visual system.

Retinocollicular connections form precise topographical maps that are normally completed through the selective elimination of misplaced axons and the stabilization of topographically ordered axon terminals during early development. Omega-3 fatty acids, acquired exclusively through the diet, and its main metabolite, docosahexaenoic acid (DHA), are involved in brain development and synaptic maturation. We have previously shown that the nutritional restriction of omega-3/DHA results in abnormal retinocollicular topographical fine-tuning. Therefore, we studied the role of omega-3 fatty acids nutritional supplementation and the developmental time windows during which this postnatal supplementation would restore normal topographical maps in the visual system. Female rats and their litters were chronically fed with either control (soy oil) or restricted omega-3 (coconut oil) diets. Fish oil supplementation was introduced between either postnatal day (PND) 7-13, PND7-28 or PND21-42. At PND13, PND28 or PND42, animals received an anterograde eye injection of a neuronal tracer to visualize retinocollicular axons. Confirming previous observations we found that an omega-3/DHA deficiency resulted in an abnormally high innervation density of retinal axons at the visual layers of the superior colliculus (SC). Although a short-term fish oil supplementation between PND7-13 could not restore normal retinocollicular topography, an extended treatment between PND7-28 completely recovered normal innervation densities of retinotectal axons. However, a late onset supplementation protocol, between PND28-42, was no longer effective in the restoration of the abnormal topographical pattern induced by an early omega-3 nutritional malnutrition. The results suggest a critical period for omega3/DHA dietary intake for the proper development of visual topographical maps.

Status of cis and trans fatty acids in Brazilian adolescent mothers and their newborns.

STUDY OBJECTIVE: The objective was to quantify cis and trans fatty acids in maternal plasma and infant cord plasma from adolescent mothers. DESIGN: From 80 adolescent healthy mothers, we sampled postpartum maternal blood and umbilical cord blood at birth. Trans fatty acids (tFAs), linoleic (18:2), and arachidonic (AA, 20:4) acids of the n-6 family, and α-linolenic (18:3), eicosapentaenoic (20:5) and docosahexaenoic (22:6) acids of the n-3 family were analyzed by gas-liquid chromatography. Results were expressed as a percentage of total fatty acids. RESULTS: Linoleic fatty acid was present in greater proportions in the maternal plasma than in that of the umbilical cord, whereas AA was present in greater proportions in the total lipids of umbilical cord blood. Docosahexaenoic acid was the long-chain polyunsaturated fatty acid of the n-3 family that was predominant in both maternal and umbilical cord plasma. The tFAs in the maternal plasma had a negative correlation with oleic acid and linoleic acid. Linolenic acid had a positive correlation with cephalic perimeter upon birth. A tendency for a negative correlation between trans isomers and gestational age at birth (P = .05) was observed. CONCLUSIONS: Long-chain polyunsaturated fatty acids, which are important to fetal growth and development, were found in greater quantities in the cord blood of newborns of adolescents than in the maternal blood, indicating a priority of transfer of AA and docosahexaenoic fatty acids to the fetus. Despite the lower levels of tFAs found in maternal blood, we verified potential risk for premature birth.

Topographic trace-elemental analysis in the brain of Wistar rats by X-ray microfluorescence with synchrotron radiation.

Knowledge about the spatial distribution and the local concentration of trace elements in tissues is of great importance, since trace elements are involved in many biological functions of living organisms. However, there are few methods available to measure the spatial (two (three)-dimensional) elemental distribution in animal brain. X-ray microfluorescence with synchrotron radiation is a multielemental mapping technique, which was used in this work to determine the topographic of iron, zinc and copper in coronal sections of female Wistar rats of different ages. Young (14 days old) and middle-aged (20 months old) rats (n = 8) were analyzed. The measurements were carried out at the XRF beam line at the Synchrotron Light National Laboratory (Campinas, Brazil). Two-dimensional scanning was performed in order to study the tendency of elemental concentration variation. The acquisition time for each pixel was 10 s/step and the step size was 300 microm/step in both directions. It was observed that the iron distribution was more conspicuous in the cortical area, thalamus and bellow the thalamus. On the other hand, the zinc distribution was more pronounced in the hippocampus. The iron, copper and zinc levels increased with advancing age. Therefore, this study reinforces the idea that these elements are involved in the chemical mechanisms of the brain that induce some neurological diseases, since they are also present in high levels in specific areas of the brain, such as the hippocampus and the substantia nigra of patients with these disorders.

Trans fatty acids in maternal diet may impair lipid biosynthesis in mammary gland of lactating rats.

Although trans fatty acids are known to influence essential fatty acid (EFA) metabolism and serum levels of lipids and lipoproteins, little is known about their effects on the metabolism of mammary glands (MGs) during lactation. In this study, 5 groups of lactating Wistar rats were fed semisynthetic diets containing 7% soy oil (control); 7% partially hydrogenated vegetable oil (7% PHVO); 13% PHVO +7% soy oil (13% PHVO); 5% PHVO +2% soy oil (5% PHVO), and 3.5% PHVO +3.5% soy oil (3.5% PHVO). Dams were killed on the 12th day of lactation. Weight, lipid content (LC), in vivo lipogenesis rate (LR) and activity of the lipogenic (ATP-citrate lyase and malic) enzymes were evaluated in the MGs. Maternal food intake, weight gain, and total MG weight were not found to be significantly different between the groups. The groups with 13, 7 and 5% PHVO presented a lower (p < 0.05) LR in MGs when compared to controls, whereas MG LC was higher in the 7 and 13% groups than in controls. The observed decrease in MG lipogenesis was accompanied by a diminution (p < 0.05) in the activities of ATP-citrate lyase and malic enzymes. These data indicate a potential impairment of lipid metabolism in the MG by trans isomers in lactating rats.

Apparent digestibility and proteic quality of the basic diet of Rio de Janeiro State complemented with multimixture.

Some factors in food can influence the protein digestibility positively or negatively. The protein quality is related to the protein synthesis capacity, growth, maintenance, reproduction and reconstitution of an organism. This work aims to determine the apparent digestibility coefficient and the protein quality of the standard basic diet of Rio de Janeiro State (HERJ), complemented with 2% of the multimixture (HERJ + MM), during rats' gestation and lactation periods. The results indicated a lower apparent digestibility coefficient (P < 0.05) during the gestation and lactation periods in HERJ diets (82.4% +/- 0.55; 80.64% +/- 1.7) and HERJ + MM (80.9% +/- 3.28; 81.7% +/- 1.2), in comparison to the casein diet (91.8% +/- 0.6; 93.9% +/- 0.4). There was no significant difference (P < 0.05) between HERJ diet (2.75 +/- 0.14) and HERJ + MM diet (2.53 +/- 0.18). However, the casein diet has showed a higher lactation value (3.27 +/- 0.3) in comparison with the two above mentioned groups. Therefore the use of the multimixture at 2% level neither impairs the apparent digestibility coefficient nor does it change the protein quality of the standard diet of Rio de Janeiro State.

Ethanol intake during lactation impairs milk production in rats and affects growth and metabolism of suckling pups.

From parturition, lactating Wistar rats were given 20% alcohol in drinking water and fed a solid diet ad lib (group AL). Pair-fed (PF) and control (C) rats were fed solid diet and given water ad lib (C). All animals were sacrificed on the 12th day of lactation. Ethanol treatment decreased food intake and milk production in lactating rats to a greater level than in PF rats, and a greater reduction in body weight of the AL pups was noted. Brain weight, protein concentration, and DNA content were also lower in pups of AL dams than of PF dams, whereas liver glycogen concentration was higher in the former. Pups from AL dams had higher circulating levels of beta-OH-butyrate, triglyceride, and free fatty acids than those from either C or PF dams. Plasma glucose concentration was lower in both PF and AL than in C pups, whereas the AL group had lower plasma protein concentration than any of the other groups. We conclude that maternal alcohol intake during lactation greatly impairs milk production, and although the known increase of lipid content in milk in rats studied under similar conditions allows an enhanced lipidic components in the pups, this adaptation does not allow normal growth and brain development.

Effects of ethanol intake on retinol concentration in the milk of lactating rats.

The effect of the consumption of ethanol (5%) on retinol concentration in milk was studied in the rat on day 12 after delivery, together with the evolution of dam body weight and pup growth rate. Female Wistar rats receiving alcohol (5%) in drinking water during lactation (N = 7) were compared to normal controls fed ad libitum (N = 6). The mean maternal alcohol intake was 3.96 +/- 0.23 g/kg body weight per day. To determine retinol levels in milk we used the Bessey and Lowry method, modified by Araújo and Flores ((1978) Clinical Chemistry, 24:386-392). The pups were separated from dams for a 2-4-h period, after which the dams were injected intraperitoneally with anesthetic and oxytocin. The concentration of retinol in milk was 162.88 +/- 10.60 micrograms/dl in the control group and 60.02 +/- 8.22 micrograms/dl in the ethanol group (P < 0.05). The ethanol group consumed less food than the controls and lost a significant amount of weight during lactation. On days 8, 10 and 12, the body weight of the pups from rats given ethanol (13.46 +/- 0.43, 16.12 +/- 0.48 and 18.60 +/- 0.91 g, respectively) were significantly lower (P < 0.05) than the weight of pups from controls (15.2 +/- 0.44, 18.36 +/- 0.54, 20.77 +/- 0.81 g). These data show that ethanol intake during the suckling period, even at low concentrations, decreases the amount of retinol in milk and, therefore, the amount available to the pups.

Effects of ethanol intake on retinol concentration in the milk of lactating rats

The effect of the consumption of ethanol (5 percent) on retinol concentration in milk studied in the rat on day 12 after delivery, together with the evolution of dam body weight and pup growth rate. Female Wistar rats receiving alcohol (5 percent) in drinking water during lactation (N=7) were compared to normal controles fed ad libitum (N=6). The mean maternal alcohol intake was 3.96 + 0.23 g/kg body weight per day. To determine retinol levels in milk we used the Bessey and Lowry method, modified by Araújo and Flores (1978) Clinical Chemistry, 24:386-392). The pups were separated from dams for a 2-4h period, after which the dams were injected intraperitoneally with anesthetic and oxytocin. The concentration of retinol in milk was 162.88 + 10.60 mug/dl in the control group and 60.02 + 8.22 mug/dl in the ethanol group (P<0.05). The ethanol group consumed less food than the controls and lost a significant amount of weight during lactation. On days 8, 10 and 12, the body weight of the pups from rats given ethanol (13.46 + 0.43, 16.12 + 0.48 and 18.60 + 0.91 g, respectively) were significantly lower (P<0.05) than the weight of pups from controls (15.2 + 0.44, 18.36 + 0.54, 20.77 + 0.81 g). These data show that ethanol intake during the suckling period, even at low concentrations, decreases the amount of retinol in milk and, therefore, the amount available to the pups.

Effects of ethanol intake on lipid metabolism in the lactating rat.

Female rats receiving alcohol (20%) in drinking water during lactation (AL) were compared to pair-fed animals (PF) and normal controls (C) fed ad lib. All animals were killed on the 12th day of lactation. When compared to C rats, food intake decreased in both AL and PF groups, and this effect was followed by a lower body weight and mammary gland (MG), liver, and parametrial adipose tissue weights. Mammary glands triacylglyceride concentration (TG) was much lower in PF than in AL, although in the latter, values did not reach those of C, and had higher liver TG concentration than any of the other groups. Both PF and AL rats had lower plasma TG, glycerol, and free fatty acid concentrations and higher beta-hydroxybutyrate concentration than C rats. When compared to C rats, the rate of lipogenesis in MG was higher in both PF and AL rats, whereas in liver it was higher in PF and lower in AL rats, and in adipose tissue it was higher in PF and unchanged in AL rats. The appearance of 14C lipids 4 h after oral [14]triolein in both MG and liver was lower in AL and PF rats and only lower in adipose tissue of AL rats as compared to the c rats. Lipoprotein lipase and hormone-sensitive lipase activities were lower in MG in both PF and AL rats than in C, whereas in adipose tissue the activity of lipoprotein lipase did not differ between AL and C rats and the activity of HSL was lower in the former. These findings therefore show that in spite of reduced uptake of orally administered triglycerides due to decreased LPL activity, maternal alcohol feeding during lactation in the rat preserves the mammary gland triglyceride content thanks to enhanced lipogenetic activity. On the other hand, it causes liver triglycerides accumulation, probably as a result of the decreased rate of triglycerides released into circulation, and these changes are not caused by the reduced food intake of the animals.

Effect of ethanol intake during lactation on the metabolism of dams and on pup development.

Ethanol intake during lactation causes growth deficiency and decreased plasma and liver protein content in pups. The lipid content of pup liver and brain was similar to that of the control group. Mammary gland protein content decreased, but the rate of lipogenesis in this gland was increased. This fact may be relevant to an adequate supply of lipid substrate to the pups.