Effects of different dietary phospholipid levels on growth performance, fatty acid composition, PPAR gene expressions and antioxidant responses of blunt snout bream Megalobrama amblycephala fingerlings

Abstract

A 60-day feeding trial was conducted to evaluate the effects of different levels of dietary phospholipid (PL) from soybean lecithin on growth performance, liver fatty acid composition, peroxisome proliferator-activated receptor (PPAR) gene expression levels and antioxidant responses of blunt snout bream fingerlings. Fish (average initial weight 0.35 ± 0.01 g) were fed five experimental diets containing the following inclusion levels of PL: 0, 2, 4, 6 and 8%. Results showed that final body weight, weight gain and specific growth rate increased significantly (P < 0.05) as dietary PL level increased from 0 to 6%, meanwhile the survival was not affected by dietary PL supplementation. Increasing dietary PL level significantly (P < 0.05) increased in 20:4n-6 content in neutral lipid of liver, indicating fish had the capacity to convert C18 to C20 and C22 by elongation and desaturation. The expression levels of PPAR-α and PPAR-γ and the activities of catalase, superoxide dismutase and glutathione peroxidase in liver were significantly (P < 0.05) increased, and liver thiobarbituric acid reactive substances value was decreased with dietary PL supplementation up to 6% compared with the control. Therefore, it was concluded that supplementation of 6% (18.8 g kg(-1), polar lipid of diet) PL could improve growth performance of blunt snout bream fingerlings.

Effects of different dietary soybean oil levels on growth, lipid deposition, tissues fatty acid composition and hepatic lipid metabolism related gene expressions in blunt snout bream (Megalobrama amblycephala) juvenile

“…Nevertheless, the molecular mechanisms underlying the effect of high dietary SO level on hepatic lipid deposition in fish requires further study. In this study, the liver and muscle FA profile of blunt snout bream generally reflected the dietary FA composition and is in agreement with other studies (Sun et al, 2011;Li et al, 2015a). The proportion of LA in liver and muscle of blunt snout bream increased with increasing SO in the diet.…”

“…However, in the liver and muscle, other LC-PUFAs such as ARA, EPA and DHA were also found in fish fed the SO groups diets and the ARA content was significantly increased by the dietary SO supplementation. This suggested that blunt snout bream was able to elongate and desaturate LA and LNA to their end products, which is in agreement with our previous studies on blunt snot bream fingerlings (Li et al, 2015a), and other studies with freshwater fish (Sargent et al, 2002;Ruyter et al, 2006;Turchini et al, 2006;Blanchard et al, 2008). On the other hand, in contrast to the ARA, the EPA, DHA and total n−3 PUFA content in the liver and muscle were significantly lower in the 56%SO and 100%SO groups compared to the other SO groups.…”

“…In the present study, the highest expressions of PPAR-α and PPAR-β were detected in the liver of fish fed the 20%SO diet and was down-regulated in those fed dietary SO levels from 20% to 100%. Similarly, our previous study found the highest expression of PPAR-α in the liver of blunt snout bream fingerlings fed a diet with optimum level of phospholipid rich in LA (Li et al, 2015a). This indicates that the optimum level of LA increased the mRNA gene expressions of PPAR-α and incomplete or excessive intake of this n − 6 PUFA may suppress PPAR-α expression in fish.…”

Growth Performance, Fatty Acid Composition, Peroxisome Proliferator‐activated Receptors Gene Expressions, and Antioxidant Abilities of Blunt Snout Bream, Megalobrama amblycephala, Fingerlings Fed Different Dietary Oil Sources

“…Li et al () reported that the expression of PPAR‐γ in blunt snout bream was highest in liver, because liver is one of the most important organs regulating glucose and lipid metabolism. Our previous study also showed that the increasing dietary soybean lecithin (rich in LA) levels upregulated the expressions of three isoforms of PPARs in blunt snout bream fingerlings (Li et al ). Thus, based on these results, it was suggested that dietary LA or n‐6 LC‐PUFA might upregulate the expressions of three isoforms of PPARs.…”

Growth performance, fatty‐acid composition, lipid deposition and hepatic‐lipid metabolism‐related gene expression in juvenile pond loach Misgurnus anguillicaudatus fed diets with different dietary soybean oil levels

“…pparα and pparγ are two key transcription factors that are involved in lipid metabolism. pparα plays an important role in the catabolism of fatty acids by up‐regulating the expression of several key enzymes involved in fatty‐acid oxidation (Lu et al ., ; Li et al ., ), while pparγ plays pivotal role in the regulation of lipogenesis and promotes lipid storage (Zheng et al ., ). The finding that dietary SO supplementation down‐regulated expression of pparα gene but up‐regulated pparγ mRNA levels in the liver, was consistent with the increased lipid content in the liver.…”