Effects of Dietary Soy Protein Concentrate on Growth, Digestive Enzymes Activities and Target of Rapamycin Signaling Pathway Regulation in Juvenile Soft-Shelled Turtle, <i>Pelodiscus sinensis</i>

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.

Physiological responses in vitamin C system during hibernation in juvenile Chinese soft-shelled turtle Pelodiscus sinensis

Vitamin C (Vc) is an important antioxidant that helps turtles tolerating stressful environment. This work quantified changes in tissue Vc levels during winter hibernation in the soft-shelled turtle Pelodiscus sinensis , to reveal the stress response pattern of tissue Vc during hibernation and contribute basic data for turtle culture. We sampled juvenile soft-shelled turtles at pre-hibernation (17.0°C mud temperature;MT), during hibernation (5.8°C MT) and after arousal (20.1°C MT) in the field. The transcript levels of the gene encoding L-gulonolactone oxidase (GLO), the key enzyme for Vc synthesis, decreased significantly during hibernation. However, GLO activity did not match the GLO transcription patterns and remained stable during hibernation, and showed temperature-dependent kinetic characteristics. Vitamin C levels in the brain, liver, kidney, and spleen (but not muscle) all decreased significantly during hibernation, but recovered to pre-hibernation levels or even higher levels after arousal. The soft-shelled turtle endured 5 months of hibernation with no significant oxidative damage in most tissues, except in the spleen. Splenic Vc was nearly exhausted during hibernation, accompanied by a significantly elevated malonaldehyde (MDA) level. Although the high level of oxidative damage quickly decreased after arousal, the potential tissue damage in the spleen during hibernation might account for the weakened immune capacity of turtles after hibernation.

Discovery of virus pathogen from soft-shelled turtle Trionyx sinesis

THE soft-shelled turtle Trionyx sinesis, because of its nutritional and medicinal values,

Effects of acute cold exposure on oxidative balance and total antioxidant capacity in juvenile Chinese soft-shelled turtle,Pelodiscus sinensis

Acute cold exposure may disturb the physiological homeostasis of the body in ectotherms.To date,there has been no information on the effects of cold exposure on homeostasis of reactive oxygen species(ROS)or antioxidant defense response in the Chinese soft-shelled turtle,Pelodiscus sinensis.In this study,P.sinensis juveniles were acclimated at 28℃,transferred to 8℃ as cold exposure for 12 h,then moved back to 28℃ rewarming for 24 h.We measured the ROS level and total antioxidant capacity(TAC)in the brain,liver,kidney and spleen at 2 and 12 h cold exposure,and at the end of the rewarming period.Malonaldehyde(MDA)and carbonyl protein were used as markers of oxidative damage.Turtles being maintained simultaneously at 28℃ were used as the control group.Cold exposure did not disturb the ROS balance in all 4 tissues,while rewarming raised the ROS level in the brain and kidney of P.sinensis.Cold exposure and rewarming decreased the TAC in the brain,liver and spleen but did not change the TAC in the kidney.MDA and carbonyl protein levels did not increase during the treatment,indicating no oxidative damage in all 4 tissues of P.sinensis.Our results indicated that extreme cold exposure did not impact the inner oxidative balance of P.sinensis,but more ROS was produced during rewarming.P.sinensis showed good tolerance to the harsh temperature change through effective protection of its antioxidant defense system to oxidative damage.This study provides basic data on the stress biology of P.sinensis.

Division of Chinese soft-shelled turtle intestine with molecular markers is slightly different from the morphological and histological observation

The Chinese soft-shelled turtle(Pelodiscus sinensis)is a commercially important species in Asian countries.Knowledge of its nutritional requirements and physiology is essential for determining the appropriate content of the feed for this animal.However,the lack of functional characterization of the intestine of this turtle limits the understanding of its absorption and utilization of nutritional materials.To solve this problem,this work utilized anatomical and histological methods to characterize 9 segments sampled along the anterior-posterior axis of the intestine.Furthermore,9 genes,which have been well documented in the intestine division of mammals and fish,were employed to functionally characterize the 9 sampled segments.Our results suggest that regions covering from the starting site to S3(position at 29.9%of the total length from the starting of the intestine)are the equivalent of mammalian dedumonen,and those covering S4(40.2%)and S5(65.4%),posterior to S8(92.7%),are the equivalent of the mammalian ileum and the large intestine,respectively.As to the region spaning S6(81.3%)and S7(87.3%),its functional equivalent(small intestine or large intestine)may be variable and depends on the functional genes.This molecular characterization in relation to the division of the intestine of Chinese soft-shelled turtle may contribute to the understanding of the nutritional physiology of the turtle,and promote Chinese soft-shelled turtle production.

Medicinal Soft-Shelled Turtle

Ingredients:Whole soft-shelled turtle; Chinese wolf-berry fruit(Lycium Chinese), milk vetch membrane root(Astragalus membranaceus), Chinese angelica andAmerican ginseng--about 25g of