Abstract

Six experimental diets with graded methionine levels (0.33%, 0.55%, 0.71%, 0.87%, 1.03%, 1.20%, dry matter) were formulated to quantify the dietary methionine requirement, and assess the influence of dietary methionine levels on the metabolism of protein and lipid in Ctenopharyngodon Idella fry (initial weight 0.36 ± 0.01 g) during an 8-week feeding trial. The results showed that 1.03% dietary methionine significantly improved the growth performance, protein efficiency ratio and feed utilization, compared with 0.33% methionine. Dietary methionine supplementation slightly increased survival rate. 0.55%–0.87% methionine level increased the phosphorylated protein and mRNA levels of phosphatidylinositol 3-kinase (PI3K), target of rapamycin (TOR), eukaryotic initiation factor 4E binding protein-1 and ribosomal protein S6 kinase 1. Compared with 1.20% methionine, 0.55%–0.87% methionine levels significantly increased mRNA levels of hepatic insulin-like growth factor-1 (IGF-1), carnitine palmitoyl transferase-1, peroxisome proliferator-activated receptor α, adipose triglyceride lipase and hormone sensitive lipase. The highest mRNA levels of hepatic acetyl-CoA carboxylase, sterol regulatory element-binding protein 1, stearyl-CoA desaturase and fatty acid synthetase were observed in 0.33% methionine diet. Based on specific growth rate and feed conversion ratio, the dietary methionine requirement of grass carp fry was 1.03% of diet (2.67% of dietary protein), using the broken-line regression analysis. Suitable dietary methionine could improve the growth, feed utilization and lipolysis of fry and promote protein synthesis via the IGF-1/PI3K/TOR pathway. While methionine deficiency tended to enhance hepatic lipid synthesis.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.