Serhat Turkmen

Nutrition during periconception and early development can modulate metabolic routes to prepare the offspring for adverse conditions through a process known as nutritional programming. In gilthead seabream, replacement of fish oil (FO)by linseed oil (LO) in broodstock diets, improves growth in the 4-month-old offspring challenged with a low FO and low fishmeal (FM) diets for 1 month. The present study further investigated the effects of broodstock feeding on the same offspring when they were 16-month-old and were challenged for a second time with the low FM and low FO diet for 2 months. The results showed that parental feeding with moderate FO replacement by LO combined with juvenile feeding at 4-month-old with low FM and FO diets significantly (P<0.05) improved offspring growth and feed utilisation of low FM/FO diets even when they are 16 months old, in the verge of their first reproductive season. The liver fatty acid composition was significantly affected by broodstock or reminder diets as well as by their interaction. Moreover, reduction of LC-PUFA and increase in ALA and LA in broodstock diets lead to a significant down-regulation of hepatic lpl (P<0.001) and elovl6 (P<0.01). Besides, fads2values were positively correlated to hepatic levels of 18:4n-3, 18:3n-6, 20:5n-3, 22:6n-3 and 22:5n-6. Thus, this study demonstrated the long-term nutritional programming of gilthead seabream through broodstock-feeding, and the effect of feeding a “reminder” diet during juvenile stages to improved utilization of low FM/FO diets and fish growth, and regulation of gene expression along the fish life-cycle. 

Full text can be accessed through

https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/parental-nutritional-programming-and-a-reminder-during-juvenile-stage-affect-growth-lipid-metabolism-and-utilisation-in-later-developmental-stages-of-a-marine-teleost-the-gilthead-sea-bream-sparus-aurata/3E661EDE2E0C7B153114220673AF798C

LARVI’17 – FISH & SHELLFISH LARVICULTURE SYMPOSIUM, Ghent, Belgium

Oral Presentation by Serhat Turkmen

Authors: S. Turkmen, C. Hernández-Cruz, M.J. Zamorano, S. Sarih, H. Xu, and M.S. Izquierdo

Recent evidence suggests that environmental factors experienced by the parents can have long-lasting effects the offspring or later generations. Thus, early envi- ronmental signs such as available nutrients during reproduction can modulate metabolic routes and offspring phenotype. This metabolic regulation, known as nutritional programming, and better understanding of outcomes can contribute to the prevention of consequences in offspring. Nutritional programming may also have potential applications in animal production. In aquaculture, one of the po- tential beneficial applications of nutritional programming may be the production of individuals that use more sustainable diets, such as those low in fishmeal (FM) and fish oil (FO). Our previous studies demonstrated the feasibility of ear- ly programming of fish through broodstock feeding for a better use of vegetable meals and oils and the long-term effects resulting from parental epigenetic control of embryogenesis. The objective of the present study was to further investigate the potential persistence of nutritional programming through the parental feeding in offspring later in life and to analyse the physiological or molecular mechanisms in gilthead sea bream (Sparus aurata). Also, a second study explored the potential interactions of nutritional programming and broodstock selection.

In the first trial, broodstock were fed in triplicate one of three programming diets with different levels of FO and linseed oil (LO): diet F with 100% FO, diet ML with moderate LO inclusion, 40% FO+60% LO, and diet HL with high LO 20% FO+80 LO for 1 month. Offspring feeding following commercial control. At three months of age, offspring mechanisms with either a complete (diet High F) or a low FM and FO diet (5% FM and 3% FO; diet LowF [reminder diet]) for one month. Offspring were then fed commercial diets until 16 months of age then were nutritionally challenged with LowF diet for two months. In the second trial, the possibility of increased nutritional programming effect with genetic selection was tested. One hundred and twenty broodfish were analyzed for their Δ6 desaturase (fads2) expression in blood and divided into 2 groups: high (hd) and low responders (ld). The same number of broodstock fish were selected and fed 100% FO (diet F) and 30% FO 70% LO (diet L) diets for nutritional programming. Larval performance was monitored at 3, 15, and 30dah. When offspring reached 6 months of age they were nutritionally challenged with LowF diet. Growth, biochemical composition, and expression of genes involved in lipid and energy metabolism were analyzed in both trials. Up to 60% FO replacement by LO (diet ML) in sea bream broodstock diets did not affect total number of produced eggs, fertilized eggs, hatched eggs, and survival after 3dah whereas 80% LO inclusion (diet HL) lead to a decrease on these parameters. In the 3-month-old offspring, there was no effect of parental feeding in the dietary utilization of HighF diet (P>0.05). However, offspring from broodstock fed LO showed better utilization of the LowF diet than offspring from broodstock fed diet F with 100%FO and higher desaturation products in the liver (P<0.05). In the 16-month-old offspring, there was no effect of parental feeding in growth of the offspring fed with 100%FM FO during the 3-month nutritional challenge. However, offspring that received LowF diet during the nutritional challenge and obtained from broodstock fed LO grew better if nutri- tionally challenged again with the LowF diet. These results denoted a continuous nutritional programming effect in fish receiving a reminder diet during early juvenile stages. Moreover, increase in LO in parental diets markedly affected ex- pression of genes related to lipid and energy metabolism such as lpl, elovl6, orcpt1. Therefore, a strong transgenerational effect of broodstock feeding on off- spring metabolism and growth performance was observed in the 16-month-old offspring. In the second trial, spawning quality was similar after 1 month feeding common commercial diets. However, subsequent feeding of these treatments with experimental diets decreased total number of eggs and survival of 3dah lar- vae in Fld and Vld groups (P<0.05). Interestingly, feeding high fads2 group with VO resulted similar results with FO diet (P>0.05). However, total length of Vhdwas smaller compared with Fhd after 3dah and Fld had longer length than Fhdand Vld at 15dah (P<0.05). All the groups had similar length at 30dah. Egg n-3 LC-PUFA content was higher in broodstock fed with F diet. When juveniles were challenged with lowFOFM at 6 months, hd groups showed higher growth and broodstock diet did not show nutritional programming effect in growth. Liv- er gene expression related to lipid and energy metabolism was also affected.

Partial replacement of FO by LO in parental diets during gilthead sea bream reproduction induces long-term persistent effects on offspring transcription in genes that regulate energy metabolism in liver and these long-term effects on gene transcription are further enhanced by feeding the offspring juveniles with diets high in VO and VM that affected phenotype and improved growth and feed utilization. Moreover, genetic selection can further improve utilization of target nutrients as an additional factor to nutritional programming.