serhat – Page 2

Long time effects of parent’s diet and “reminder” programming effect of 16 month juveniles

4th May 2015 by serhat Leave a Comment

Presented as a poster in Epiconcept Cost Action’s workshop Periconception Environment

26-29 April 2015, Dubrovnik, Croatia

Nutritional programming is widely studied in vertebrates and it has been shown that nutritional stimuli during developmental stages may trigger short or/and longterm effects on several physiological functions of the organism. Studies about nutritional programming on different fish species also showed that functioning of certain metabolic pathways involved in lipid and carbohydrate metabolism of juveniles may be influenced by an early diet. Our research on sea bream revealed that nutritional programming through broodstock nutrition is very effective and improves the ability of 4 month juveniles to use vegetable oils (VO) and vegetable meals (VM). However, it is still unknown longer term effects of this type of programming. The present study examined the longterm influences of programming through broodstock nutrition in 16 month juveniles. Therefore, sea bream broodstock were fed four different replacement levels of fish oil (FO) by VO. FO replacement by VO affected growth of 45 day and 4 month-old juveniles, as well as Δ6 desaturase gene expression. Besides, when 4 month-old juveniles were fed with a VO-VM based diet, fish from broodstock fed VOs utilized more effectively this diet and showed a higher growth. Afterwards, all fish were fed with a standard fishmeal/FO based commercial diet for 16 months. Then, fish were challenged with a VM/VO based diets for 2 months. The results showed that the influence of parental feeding had disappeared on 16 month-old fish. However, those fish that were challenged at 4th month with a VM-VO based diet significantly showed the effect of parental feeding, suggesting that the nutritional challenge at 4 months may acted as a “reminder” effect added of the parental programming. Furthermore, long effects of nutritional programing and a remainder diet on fatty acids and gene expression involved in lipid metabolism were studied. Grant support:European Commission Directorate for Research & Innovation Grant A KBBE-2001-5-288925 (ARRAINA)

Meeting’s web page

Nutritional reprogramming in fish: Importance of developmental windows

8th April 2015 by serhat Leave a Comment

Presented in Epiconcept Cost Action’s workshop Epigenomic Toolbox: from Methods to Models.

07-09 May 2014, Las Palmas, Spain

Studies in mammals and humans show that dietary influences exerted at critical developmental stages early in life (neonatal nutrition, post-natal nutrition) may have long-term consequences on physiological functions in later life. Nutritional programming phenomenon is largely studied in mammalian models for the understanding of diseases such as the metabolic syndrome or diabetes. The functioning of certain metabolic pathways such as fatty acid metabolism in juvenile fish also depends on specific nutritional signals during the critical larval periods, demonstrating that the concept of metabolic programming also exists in fish. Modulation of key enzymes for fatty acid synthesis is possible by feed given to juveniles. The present study will examine the influences early nutritional programming either during embryonic phase or during metamorphosis. To affect nutrient intake during these two periods either broodstock or early weaning diets were modified and their effects studied on sea bream performance, lipid metabolism, gene expression and response after a feeding challenge. Specific genes such as those involved in essential fatty acids metabolism, were markedly affected by the nutritional programing at both developmental windows. For instance an up regulation of delta-6 desaturase gene expression was obtained when fish was conditioned with moderate levels of vegetable oils, whereas extreme conditioning conditions inhibited the expression. Despite it was potentially possible to condition fish during metamorphosis, the larvae were very sensitive during this period and high mortalities occurred during the treatment. When fishes were programmed through broodstock nutrition, a very high survival rate was obtained. Even extreme conditioning produced reliabe survival rates. After treatment with different conditioning during the embryonic period, all fish were fed standard fishmeal diet for three months and, afterwards, challenged with vegetable oils. A significant positive effect of the nutritional programming was observed in lipid metabolism response as well as a better utilization of the feeds. Grant support: European Commission, Directorate for Research & Innovation, Grant Agreement KBBE-2001-5-288925 (ARRAINA)

Meeting’s web page

Growth response of European sea bass under different starvation cycles and feeding rates

1st April 2015 by serhat Leave a Comment

The compensatory growth response of the European sea bass (Dicentrarchus labrax) faced cycling starvation and restricted ration was assessed. Juveniles (10.5 g) were stocked into 15 tanks at a density of 25 fish per tank. Five different feeding regimes were tested on triplicate groups of fish: C_Satiation: control fed for 60 days without deprivation, C_Restricted: 25% restricted feeding, S-R: 1 day starvation then 4 days C_Restricted feeding, R-F: 1 day C_Restricted feeding then 4 days C_Satiation feeding, and, finally, S-F: 1 day starvation then 4 days C_Satiation feeding. The specific growth rate of fish in the C_Satiation (2.5±0.06 %/day), S-F (2.5±0.11 %/day) and R-F (2.4±0.18 %/day) were significantly higher than that of C_Restricted (2.2±0.05 %/day) or S-R (2.0±0.01 %/day). Fish in S-F group was able to achieve catching up with the C_Satiation. There was no significant difference in feed conversion rates but R-F and S-F consumed ~34% more feed than C_Satiation following the first re-feeding day. While the highest lipid content was observed in C_Satiation(14.4 %), S-R (33.3 % dry matter) had the highest water content compare to the C_Satiation and C_Restricted(37.8 and 36.9 % dry matter, respectively). In conclusion, it may be concluded that sea bass has rapid response to cycling starvation/re-feeding and that a 25% restricted feeding ratio is insufficient to invoke a compensatory growth response in sea bass.

Link to article: http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2109.2011.02970.x/abstract