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.

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.

To investigate the effects of supplementing the diet with Caulerpa lentillifera on the growth performance, antioxidant capacity, and intestinal microbiota of Litopenaeus vannamei, a total number of 600 healthy shrimp, each having an average body weight of 2.45 ± 0.12 g, were allocated randomly into five experimental groups. These groups comprised a control group receiving a basal diet (Ctrl) and four treatment groups receiving the basal diet supplemented with varying concentrations of dried C. lentillifera powder: 2.5% (CL1), 5% (CL2), 7.5% (CL3), and 10% (CL4). Each group consisted of four replicates, with 30 shrimp per replicate. The experimental duration was 56 days. The findings demonstrated that supplementing the diet with 5–7.5% C. lentillifera enhanced growth performance and significantly increased the crude protein content in whole shrimp (p < 0.05). Based on the feed conversion ratio (FCR) and protein efficiency ratio (PER) metrics, the optimal inculusion range of C. lentillifera in L. vannamei feed was determined to be 5.25–7.15%. Simultaneously, there was a significant increase in the activities of total superoxide dismutase (T-SOD), glutathione peroxidase (GPx), and peroxidase (POD) enzymes in the hepatopancreas, accompanied by a substantial reduction in malondialdehyde (MDA) levels (p < 0.05). Dietary supplementation with 5–7.5% C. lentillifera induced a numerical elevation of the relative expression levels of antioxidant and protein synthesis genes, although no statistically significant differences were detected among all groups (p > 0.05). Analyses of intestinal microbiota sequencing revealed that the addition of 5–7.5% C. lentillifera improved the intestinal microbiota’s composition and structural characteristics with a focus on metabolic pathways. In conclusion, the inclusion of dietary C. lentillifera positively influenced growth performance, antioxidant capacity, and the intestinal microbiota of L. vannamei. However, excessively high-dose dietary levels may have adverse effects on shrimp; thus, a dietary inclusion level of 5.25–7.15% C. lentillifera is recommended.