Author(s)

Fan Zhou^1*, Yaqin Wang², Li Tang³, Yong Huang³, Xueyan Ding¹, Zhongyang He¹

¹Zhejiang Fisheries Technical Extension Station, Hangzhou, China.
²College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.
³College of Animal Sciences, Zhejiang University, Hangzhou, China.

Soft-shelled turtle, Pelodiscus sinensis is important aquatic species in China, and searching for alternatives protein resources to fish meal (FM)-based feeds in feed has become urgent and important for its sustainability development. The present study was conducted to assess the effects of dietary soy protein concentrate (SPC) on growth, digestive enzymes and target of rapamycin (TOR) signaling pathway of juvenile P. sinensis (4.56 ± 0.09 g). SPC was applied to replace FM protein at 0%, 15%, 30% and 60% (designated as T0, T15, T30 and T60, respectively), and each diet was fed to triplicate groups. The results showed that there was no significant difference in growth performance and feed utilization except of the turtles fed with T60 diet, of which showed poorer daily weight gain and feed conversion rate. The pepsin/trypsin and Na⁺-K⁺ ATP-ase activities decreased dramatically when SPC level increased, and lipase activities in liver and intestinal tract also showed decline tendency. However, amylase activities were unaffected. No significant differences were observed in TOR, S6K1 and 4E-BP1 genes mRNA expression level of TOR signaling pathway among the treatments. However, the relative phosphorylated level of these proteins decreased significantly when SPC level increased. The present study indicated that high SPC substitution level would suppress digestive enzymes and TOR signaling pathway proteins phosphorylated level and eventually result in growth reduction of P. sinensis.

Soft-Shelled Turtle P. sinensis, Soy Protein Concentrate, Growth Performance, Digestive Enzymes, Target of Rapamycin Signaling Pathway

Zhou, F. , Wang, Y. , Tang, L. , Huang, Y. , Ding, X. and He, Z. (2015) Effects of Dietary Soy Protein Concentrate on Growth, Digestive Enzymes Activities and Target of Rapamycin Signaling Pathway Regulation in Juvenile Soft-Shelled Turtle, Pelodiscus sinensis. Agricultural Sciences, 6, 335-345. doi: 10.4236/as.2015.63034.