Nanoencapsulated α-lipoic acid reduces the negative effects of high soybean meal diets in the white shrimp, Penaeus vannamei

Abstract

The present study assessed the effects of chitosan nanocapsules loaded with α-lipoic acid (NcLA) on the performance of Penaeus vannamei under nutritional stress induced by high soybean meal (SBM) content. The nanocapsules (with an average size of 183.4 nm) were prepared and incorporated into shrimp feed formulated to contain 44% SBM of total diet, resulting in an isoproteic and isolipid diet containing 40% crude protein and 7% lipid. Each dietary treatment was performed in triplicate and included nanocapsules containing α-lipoic acid at 0, 75, 150, and 300 mg kg⁻¹ (designated NcLA-0, NcLA-75, NcLA-150, and NcLA-300, respectively). Shrimp (initial weight of 0.22 ± 0.02 g) were fed four times daily. After 42 days, significant differences in growth were observed. The NcLA-150 treatment showed the highest values for thermal growth coefficient (TGC; 1.25 ± 0.08; P < 0.021) and specific growth rate (SGR; 7.91 ± 0.34; P < 0.024), with significant differences. The survival rate was 70% in the control group, whereas the experimental treatments ranged from 76 to 82% with no significant differences among them. Histological examination of the hepatopancreas revealed a tendency toward recovery in the NcLA-150-treated shrimp compared to the control group. Although the statistical value was not significant (P = 0.07), there was a tendency toward improved hepatopancreatic condition compared with the control group, which exhibited clear disruptions of hepatopancreatic tissues. Additionally, although no significant differences were observed in the ANOVA, the polynomial gene expression analysis of antioxidant enzymes showed a descriptive U-shaped trend for hepatopancreatic MnSOD and TRX, whereas CAT and GPx exhibited minimal variation. The study concludes that nanoencapsulated α-lipoic acid can modulate the physiological response of P. vannamei to diets high in soybean meal, demonstrating a dose–response effect. Specifically, a feed containing 150 mg kg⁻¹ nanoencapsulated α-lipoic acid, under our experimental conditions, can mitigate damage caused by excessive antinutritional factors. However, it is recommended to conduct more research with a wider range of doses and use more individual sampling to reduce the standard deviation among treatments, to get a clearer picture, and then recommend the optimal dosage to avoid reversing the benefits.