Authors
Xishuai Cui, Min Jin, Hongyu Peng, Tiantian Xu, Xiaoyue Li, Shichao Xie, Wenhao Zhan, Yao Deng, Yinqiu Tian, Zheng Tang, Tingting Zhu, Peng Sun, Qicun Zhou
Published in
Animal nutrition (Zhongguo xu mu shou yi xue hui). Volume 26. Pages 633-651. Epub Jul 09, 2026.
Abstract
A 63-d feeding trial was performed to determine the effects of varying dietary leucine levels on the growth, protein metabolism, and disease resistance of Scylla paramamosain against Vibrio parahaemolyticus. A total of 360 juvenile crabs (approximately 50 d after metamorphosis from the megalopa stage and having undergone eight molts; initial weight: 8.65 ± 0.58 g) were randomly assigned to six dietary treatments, with 60 crabs per group, each treatment comprising three replicates of 20 crabs each. Each group was fed one of the six isonitrogenous and isolipidic diets, which were formulated to provide graded leucine levels of 1.81% (control), 2.10%, 2.40%, 2.67%, 2.91%, and 3.18%, respectively. The results showed that crabs fed diets with 2.67% leucine exhibited significantly higher percent weight gain (PWG), molting frequency, and protein efficiency ratio, together with a lower feed conversion ratio, than those fed diets with 1.81%, 2.10%, or 3.18% leucine (P < 0.05). Muscle and hepatopancreas protein contents were significantly higher in the 2.67% and 2.91% leucine groups than in the 1.81% leucine group (P < 0.05). Dietary leucine also altered the muscle amino acid profile and enhanced hepatopancreatic digestive enzyme activities (P < 0.05). At leucine levels of 2.67%-2.91%, leucine significantly upregulated selected mTOR-related genes and increased TOR and p70S6K1 protein levels (P < 0.05). Following V. parahaemolyticus challenge, the 2.91% leucine group showed the highest survival and lower hemocyte apoptosis (P < 0.05). The overall survival difference showed a tendency (log-rank P = 0.056), whereas Cox regression indicated a reduced mortality risk versus the 1.81% leucine group (P = 0.024). Compared with the control, leucine supplementation significantly enhanced antioxidant capacity and innate immune enzyme activities, accompanied by increased expression of antioxidant, immune, amino acid transporter, mTOR signaling, and inflammatory-response genes (P < 0.05). Based on PWG against dietary leucine levels, the optimal dietary leucine requirement was determined to be 2.70% for mud crab under the present crab-apartment recirculating aquaculture system rearing conditions, whereas dietary 2.91% leucine was associated with a significantly reduced mortality risk during the 48-h V. parahaemolyticus challenge period (Cox model).
PMID:
42602815
Bibliographic data and abstract were imported from PubMed on 15 Aug 2026.
Read full publication at:
Please sign in
to see all details.
Advertisement
Stats
- Recommendations n/a n/a positive of 0 vote(s)
- Views 9
- Comments 0