The protein level of isoenergetic formulae does not modulate postprandial insulin secretion in piglets and has no consequences on later glucose tolerance

Early postnatal nutrition is involved in metabolic programming, an excess of protein being suspected to enhance early growth and the propensity to later develop insulin resistance and type 2 diabetes mellitus. The aim of the present study was to test the hypothesis that excessive protein intake during the suckling period would overstimulate the endocrine pancreas in the short term and alter durably its maturation, contributing to the later disruption of glucose homeostasis. Normal-birth-weight and low-birth-weight piglets were fed isoenergetic formulae providing an adequate-protein (AP, equivalent to sow milk) or a high-protein (HP, +48%) supply between 7 and 28d of age and were fed a standard diet until 70d of age. During the formula-feeding period, the HP formula did not modify postprandial insulin secretion but transiently increased fasting insulin and the homeostasis model assessment-insulin resistance index (HOMA-IR, P<0·05). Fasting insulin and HOMA-IR were restored to AP piglets' values 1month after weaning. The structure of the endocrine pancreas was not affected by the protein content of the formula. The weight at birth had no major effect on the studied parameters. We concluded that a high-protein supply during the suckling period does not interfere with insulin secretion and endocrine pancreas maturation in the short term. It has no consequences either on glucose tolerance 1month after weaning. The present study demonstrated that up-regulation of postprandial insulin secretion is not involved in higher growth observed in piglets fed a HP formul

Growth, body composition and hormonal status of growing pigs exhibiting a normal or small weight at birth and exposed to a neonatal diet enriched in proteins

Small birth weight and excess of early protein intake are suspected to enhance later obesity risk. The present study was undertaken to determine the impact of neonatal diets differing in protein content on growth, body composition and hormonal status of 70-d-old pigs born with normal weight (NW) or small weight (SW). At 7d of age, male and female suckled piglets were assigned to the NW (approximately 1·4kg at birth) or SW (approximately 0·99kg at birth) groups. They were fed milk replacers formulated to provide an adequate protein (AP) or a high protein (HP) supply for 3 weeks. From weaning to 70d of age, all animals received ad libitum the same standard diet. Growth rates were higher (P<0·05) in HP piglets than in AP piglets during formula feeding and remained higher (P<0·05) only in HP male pigs thereafter. No difference in feed consumption was detected between groups during the periods examined. Carcass lipid content and the relative weight of perirenal adipose tissue did not differ between the AP and HP pigs. Whereas plasma leptin concentration was higher (P<0·05) in HP pigs than in AP pigs with a marked difference in SW pigs, plasma insulin-like growth factor (IGF)-I concentration and expression of IGF system genes were not affected by the diets. In summary, a HP intake during the suckling period induced an increase in growth rate that persisted only in male pigs during the post-weaning period. This response was not associated with any difference in adiposity parameters in this perio

Réponse du métabolisme lipidique à l'acide alpha-linolénique alimentaire (influence du sexe)

L acide a-linolénique (ALA) est un acide gras polyinsaturé de la famille n-3, dont les représentant les plus connus, EPA et DHA présents surtout dans le poisson, exercent un rôle protecteur contre les maladies cardio-vasculaires (MCV). L effet de l ALA est cependant moins bien connu. Par ailleurs les œstrogènes jouent eux aussi un rôle protecteur des MCV. Notre travail a pour objectif de mieux définir les effets métaboliques de l ALA ainsi que d étudier les interactions entre acides gras alimentaires et hormones sexuelles sur le métabolisme lipidique. Nous avons tout d'abord étudié l'effet de doses croissantes d'ALA sur sa biodisponibilité et celle de ses dérivés (EPA et DHA,notamment). A de faibles comme à de fortes doses, l'organisme est capable d'absorber, transporter et stocker l'ALA et de le convertir en EPA efficacement. Dès la plus faible dose étudiées, l'ALA induit un net effet hypotriglycéridémiant (-45%) dû à une baisse de la lipogenèse, et une légère augmentation de la cholestérolémie (+15%). Par la suite, nous avons montré, chez le hamster, que le métabolisme lipidique des mâles est plus sensibles aux acides gras alimentaires que celui des femelles. En réponse à un régime riche en ALA, les mâles ont une baisse de la triglycéridémie due à une diminution et la lipogenèse et une augmentation de l'oxydation alors que chez les femelles ces effets sont nettement moins marqués. Le métabolisme du cholestérol, est nettement plus marqué par la différence de sexe que par celle du régime. Nous avons alors cherché les mécanismes mis en jeu dans les différences de réponse des mâles et des femelles et testé puis refuté l'hypothèse d'une implication de PPARa.lpha-linolenic acid (ALA) is a polyunsaturated fatty acid from the n-3 family, like the famous EPA and DHA found in fish, that are known to exert protection against cardiovascular diseases (CVD). Effects of ALA are, however, less known. In addition, estrogens protect also against CVD. The aim of our work was to define metabolic effects of ALA and to study the interactions between dietary fatty acids and sex hormones on lipid metabolism and risk factors of CVD. We have first study the effects of increased doses of ALA on its own biodisponibility and that of its derivatives EPA and DHA. At low as well as at high doses, the body was able to absorb, transport and store ALA and to convert it into EPA as much efficiency. Since the lowest dose studied, ALA decreased triglyceridemia (-45%) via a decreased lipogenesis, and increased slightly cholesterolemia (+15%). Then, we observed that, in the hamster, males lipid metabolism was more sensitive to dietary fatty acids than that of females. In response to a diet rich in ALA, males triglyceridemia decreased via a lower lipogenesis and a higher oxidation. In females, however, these effects were not so clear. Cholesterol metabolism was much more affected by gender differences than by diet differences. At least, we tried to look at the mechanism underlying these different responses in males and females and tested then refuted the implication of PPARa.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Influence of gender on response of lipid metabolism to dietary fatty acids in the hamster

International audienc

Influence of phytosterol and phytostanol food supplementation on plasma liposoluble vitamins and provitamin A carotenoid levels in humans: An updated review of the evidence.

Phytosterols and phytostanols (PAP) compete with cholesterol absorption in the intestine, resulting in a 5-15%-reduction in plasma total and LDL cholesterol. An important issue is the PAP potential to reduce the plasma concentrations of fat-soluble vitamins and provitamin A carotenoids. Here, an update of the scientific evidence is reviewed to evaluate plant PAP-enriched foods impact on plasma fat-soluble vitamins and carotenoid levels, and to discuss potential implications in terms of cardiovascular risk. Based on 49 human interventional and 3 bioavailability studies, results showed that regular consumption, particularly over the long term, of foods fortified with PAP as recommended in labelling does not significantly impact plasma vitamins A, D and K concentration. A 10% significant median reduction was observed for α-tocopherol. Concerning carotenoids, while 13 studies did not demonstrate statistically significant plasma β-carotene reduction, 20 studies showed significant reductions, with median effect size of -24%. This decline can be mitigated or offset by increased fruits and vegetables consumption. Furthermore, higher cardiovascular risk was observed for differences in plasma β-carotene concentration of the same magnitude as the estimated average decrease by PAP consumption. These results are supported by the only study of β-carotene bioavailability showing decrease in absorption by phytosterols daily intake

Biodisponibilité et effets métaboliques de l'acide alpha-linolénique issu du lin chez le hamster

National audienc

Biodisponibilité et effets métaboliques de l'acide alpha-linolénique issu du lin chez le hamster

National audienc

The protein level of isoenergetic formulae does not modulate postprandial insulin secretion in piglets and has no consequences on later glucose tolerance

International audienceEarly postnatal nutrition is involved in metabolic programming, an excess of protein being suspected to enhance early growth and the propensity to later develop insulin resistance and type 2 diabetes mellitus. The aim of the present study was to test the hypothesis that excessive protein intake during the suckling period would overstimulate the endocrine pancreas in the short term and alter durably its maturation, contributing to the later disruption of glucose homeostasis. Normal-birth-weight and low-birth-weight piglets were fed isoenergetic formulae providing an adequate-protein (AP, equivalent to sow milk) or a high-protein (HP, +48 %) supply between 7 and 28 d of age and were fed a standard diet until 70 d of age. During the formula-feeding period, the HP formula did not modify postprandial insulin secretion but transiently increased fasting insulin and the homeostasis model assessment-insulin resistance index (HOMA-IR, P < 0·05). Fasting insulin and HOMA-IR were restored to AP piglets' values 1 month after weaning. The structure of the endocrine pancreas was not affected by the protein content of the formula. The weight at birth had no major effect on the studied parameters. We concluded that a high-protein supply during the suckling period does not interfere with insulin secretion and endocrine pancreas maturation in the short term. It has no consequences either on glucose tolerance 1 month after weaning. The present study demonstrated that up-regulation of postprandial insulin secretion is not involved in higher growth observed in piglets fed a HP formula

Influence de la teneur en protéines des laits artificiels d’allaitement sur les réponses glycémiques et insulinémiques post prandiales chez le porcelet pris comme modèle du nouveau-né humain

National audienc