Microencapsulation is an advanced technique used to improve the viability of probiotics and minimize sensitivity during processing, storage, and in the gastrointestinal environment. Two dietary treatments including a control and an encapsulated probiotic, Bacillus subtilis E20 (EP), were used to evaluate the efficacy in improving the intestinal microbiome of white shrimp, Penaeus vannamei, after a 60-feeding trial. The 16S rDNA next-generation sequencing (NGS) analysis indicated that shrimp fed the EP diet generated higher amplicon reads than shrimp fed the control diet. No significant differences were observed in the α-diversity index of the intestinal microbiota of shrimp that were fed the control and EP diet. At the phylum level, Proteobacteria was relatively abundant in the microbiota of shrimp fed both the control and EP diet. The treatment with EP increased the expression of Tenericutes, Bacteroidetes, and Firmicutes, more than the control. The PC analysis revealed that the EP diet altered the bacterial profile in shrimp’s intestines into forming different clusters. Unique genera such as Luteolibacter, Simkaniaceae, Haemophilus, Pirellulaceae, Filomicrobium, Sphingomonas, and Erysipelotrichaceae UCG-003 along with well-known probiotic genera Bacillus and Lactobacillus were found in the intestine of shrimp fed the EP diet. The PCA eigenvector plots indicated a higher abundance of Bacillus in shrimp fed with EP diet, but a higher abundance of Vibrio in shrimp fed with control diet. These results suggest that encapsulated B. subtilis E20 can be beneficial to shrimp microbiota.

In Taiwan, the mushroom Antrodia camphorata (AC) is used for medicinal purposes, including cancer prevention and treatment. This study aimed to investigate the effect of AC-supplemented diets on the innate immunity and disease resistance of the orange-spotted grouper Epinephelus coioides against two bacterial infections—Vibrio alginolyticus and Streptococcus iniae. Orange-spotted groupers were fed AC-supplemented diets at 0 (control), 1.5, 3.0, 4.5, and 6.0 g kg⁻¹ for 28 days and examined for innate immune responses and survival rates against V. alginolyticus and S. iniae. The results showed that the innate cellular and humoral immune parameters, including respiratory burst, phagocytic activity, and lysozyme activity of leukocytes, along with serum alternative complement activity (ACH₅₀) and superoxide dismutase activity, as well as interleukin (IL)-4 and IL-6, were all significantly increased in groupers fed AC-supplemented diets. Groupers fed diets containing AC at doses higher than 3.0 g kg⁻¹ had better survival rates than the control group 3–18 days after V. alginolyticus or S. iniae challenge. The enhanced disease resistance may be attributable to AC-induced innate immunity, suggesting that utilizing AC as a dietary supplement at 3.0 g kg⁻¹ may enhance the disease resistance of orange-spotted groupers against Vibrio or Streptococcus infection.

Groupers are among the most popular fish commodities worldwide owing to their palatability and appearance. However, their body pigmentation considerably affects their consumer acceptability and pricing, making their culture challenging. The present study aimed to improve the body pigmentation of the leopard coral grouper (Plectropomus leopardus) by investigating the effects of tank color, shading, and feed additives over 28 days. The fish were reared in tanks of different colors (white, black, red, and green), and their net cages were shaded at 0%, 50%, and 80%. The fish reared in the black and green tanks or under 80% shading exhibited the most vibrant skin coloration. Skin color enhancement was tested in feeding trials, during which the fish were fed different concentrations of additives: astaxanthin (0 (control), 1000, 2000, and 3000 mg), vitamin E (1000, 2000, and 3000 mg), and plant extracts (250, 500, and 750 mg) kg^-1 of diet. Fish fed the 3,000 mg of astaxanthin kg^-1 diet displayed the best pigment enhancement, whereas those fed with vitamin E and plant extracts showed reduced pigmentation. Feeding with different ratios (0%, 10%, 20%, and 30%) of krill meal in the diet showed that body pigmentation was best enhanced by 20–30% krill meal. In conclusion, our results imply that black- and green-colored rearing tanks under 80% shading and a diet with 20–30% krill meal and 3,000 mg astaxanthin kg^-1 constitute ideal conditions to enhance the body pigmentation of P. leopardus.

Herein, we investigated the effects of immunostimulants on the growth, immune responses, and post-infection survival of hybrid sturgeons (Huso huso♀ × Acipenser ruthenus♂). Therefore, we examined the effects of dietary supplementation of β-glucan, vitamin C, and Radix Bupleuri (Chaihu) extract (RBE) at various concentrations (0.2, 0.4, and 0.6% incorporated through feed) on the growth rate and non-specific immune responses of hybrid sturgeon. When supplemented individually, these immunostimulants significantly reduced the feed conversion ratio while promoting weight gain, with the vitamin C-administered groups showing the most pronounced differences. Further, we observed that dietary β-glucan, vitamin C, and RBE, when fed at 0.4 and 0.6% concentrations, significantly enhanced the rates of superoxide anion production and phagocytosis by head kidney leukocytes. Moreover, vitamin C and RBE supplementation at 0.4 and 0.6% and β-glucan supplementation at 0.6% concentration significantly increased the serum lysozyme activity. Further, vitamin C and β-glucan supplementation at 0.6% and RBE supplementation at 0.4 and 0.6% concentrations showed the highest survival rates after Aeromonas hydrophila infection. In conclusion, our findings highlight that the dietary supplementation of β-glucan, vitamin C, or RBE in appropriate concentrations can significantly enhance superoxide anion production and phagocytic activity of leukocytes, serum lysozyme activity, and the survival of hybrid sturgeons after A. hydrophila infection. Our results suggest that incorporating immunostimulants such as Chinese medicinal herbs at optimal levels can effectively boost the growth, immunity, and disease resistance of hybrid sturgeons in aquaculture. These results provide valuable insights for future studies on the inclusion of immunostimulants in aquaculture feed.