Hailiang Yan

Lysolecithin, characterized by its superior emulsifying and stabilizing properties, facilitates nutrient absorption and is extensively utilized in aquatic feed formulation. Nevertheless, its precise function in shrimp nutrition and physiology remains inadequately understood. This study aimed to evaluate the feasibility and optimal dosage of replacing 2% soybean lecithin with varying levels of soybean lysolecithin (0–2%) in the diet of Litopenaeus vannamei. Growth performance, antioxidant indices, and lipid metabolism were assessed. The results demonstrated that dietary supplementation with 0.1% lysolecithin had the best growth performance, significantly improved lipid retention and apparent crude fat digestibility, while reducing malondialdehyde (MDA) levels in the hepatopancreas and alleviating endoplasmic reticulum (ER) stress. The 0.1% group also exhibited better hepatopancreatic tissue structure and lipid metabolic homeostasis. In contrast, higher inclusion levels (≥1.5%) led to increased lipid accumulation and enhanced activities of lipid metabolic enzymes but were associated with a risk of oxidative stress and less favorable tissue morphology. No significant differences in antioxidant enzyme activities were observed among groups. It is hypothesized that lysolecithin may regulate lipid metabolism and homeostasis via the Ca²⁺/CaMKKβ/AMPK signaling pathway; further studies are required to confirm this mechanism. In conclusion, 0.1% soybean lysolecithin is recommended as the optimal dietary level for L. vannamei, supporting its feasibility as a substitute for 2% soybean lecithin in shrimp feed.

This study seeks to assess the impact of varying concentrations of lysophospholipids on the antioxidant capacity, digestive performance, and intestinal microbiota of L. vannamei. A total of 840 shrimp, with an average initial weight of 2.22 ± 0.11 g, were randomly distributed across 28 aquaculture tanks (30 shrimp per tank), organized into 7 distinct treatment groups, each comprising 4 replicates. The control group (DL2) was administered a basal diet formula supplemented with 2% soy lecithin, whereas the experimental groups received lysophospholipids at varying concentrations of 0% (RL0), 0.1% (RL0.1), 0.5% (RL0.5), 1% (RL1), 1.5% (RL1.5), and 2% (RL2). The results revealed that the total antioxidant capacity (T-AOC) level in the RL0.1 group was significantly elevated compared to the DL2 and RL2 groups (p < 0.05). Furthermore, glutathione peroxidase (GSH-Px) and catalase (CAT) activities were markedly higher in the RL1 and RL1.5 groups relative to other groups (p < 0.05). Superoxide dismutase (SOD) activity exhibited a significant increase across all lysophospholipid-supplemented groups when compared to the DL2 group (p < 0.05). Malondialdehyde (MDA) levels were notably elevated in the RL0.5, RL1.5, and RL2 groups relative to the other groups (p < 0.05). Regarding antioxidant-related genes in the hemocytes, the relative expression levels of Nrf1, Nrf2, GPx, SOD, CAT, and Hippo were significantly higher in the RL0.5 and RL1 groups compared to the DL2 group (p < 0.05). Additionally, the relative expression levels of GPx and SOD were significantly elevated in the RL2 group compared to the DL2 group (p < 0.05). In the intestinal tract, the activities of trypsin and α-amylase (AMS) were significantly elevated in the RL0.1, RL0.5, and RL1 groups compared to the DL2 group (p < 0.05). Additionally, the RL0.1 group demonstrated significantly higher lipase (LPS) activity than the other groups supplemented with lysophospholipids (p < 0.05). Furthermore, the relative expression levels of the trypsin and α-amylase genes were significantly increased in the RL1 and RL1.5 groups in comparison to the DL2 group (p < 0.05). Sequencing analysis of the intestinal microbiota indicated that the incorporation of lysophospholipids resulted in an enhancement of the composition and structure of the intestinal microbiota. The functional abundance of the intestinal microbiome was primarily enriched in metabolic pathways. Overall, the incorporation of lysophospholipids into the diet exerted a beneficial effect on the antioxidant capacity, digestive performance, and intestinal microbiota of L. vannamei, especially with the supplementation of 0.1% lysophospholipids.

This research sought to assess the effects of dietary supplements with Gracilaria lichenoides and Bacillus amyloliquefaciens, either individually or combined, on the growth performance, antioxidant capacity, and intestinal function of Penaeus monodon. A total of 840 shrimps were randomly assigned to 28 tanks with an average initial weight of (1.04 ± 0.03) g (30 shrimp per tank) with 7 different treatment groups and 4 replicates per treatment. The control treatment (C) consisted of a basal diet; in contrast, the experimental groups were complement with varying levels of G. lichenoides (3% or 8%), either alone (S3 and S8) or in combination with B.amyloliquefaciens at different concentrations (3% G. lichenoides and 10⁹ CFU/g—S3B9; 8% G. lichenoides and 10¹¹ CFU/g B. amyloliquefaciens—S8B11; 10⁹ CFU/g B. amyloliquefaciens—S9; 10¹¹ CFU/g B. amyloliquefaciens—B11). The results indicated that the maximum values of final body weight (FBW) (10.49 ± 0.90) g, weight gain rate (WGR) (908.94 ± 33.58) g, and specific growth rate (SGR) (4.20 ± 0.06) g were perceived in the 3% G. lichenoide diet treatment, and compared with the control group, the difference was significant (p < 0.05). The whole-body lipid content of shrimp in the B9 group was significantly higher than that in the B11 group (p < 0.05), but no significant difference was observed when compared with shrimp fed other diets (p > 0.05). The ash content of shrimp in the B9 group was found to be significantly higher than that in the S3B9 group (p < 0.05). Furthermore, the lipase activity in the stomach and intestines of the experimental groups exhibited a statistically significantly increase compared to the control (p < 0.05). In comparison to the control group, the hepatopancreas of the S3 group exhibited a significant increase in the activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and antioxidant genes [SOD, catalase (CAT), GSH-Px, thioredoxin (Trx), Hippo, and NF-E2-related factor 2 (Nrf2)] expression levels (p < 0.05). Additionally, the activities of total antioxidant capacity (T-AOC), SOD, peroxidase (POD), and antioxidant genes (CAT, GSH-Px, Trx, and Hippo) in the S3B9 treatment of hepatopancreas showed significant improvement (p < 0.05). The inclusion of dietary G. lichenoides and B. amyloliquefaciens resulted in enhanced relative expression of intestinal lipid metabolism genes (fatty acid synthetase (FAS), lipophorin receptor (LR), fatty acid transport protein 1 (FATP1)) and suppressed the expression of the long-chain fatty acid-CoA ligase 4 (LCL4) gene. Analysis of microbiota sequencing indicated improvements in composition and structure, with notable increases in Firmicutes at the phylum level and Vibrio at the genus level in the S3 group, as well as an increase in Tenericutes at the genus level in the S8B11 group. Overall, the inclusion of dietary G. lichenoides and B. amyloliquefaciens positively impacted the growth, antioxidant capacity, and microbial composition of shrimp, with particular enhancement observed in shrimp fed a supplementary 3% G. lichenoides diet.