Isoquinoline alkaloids (IQs) from Macleaya cordata are promising natural products for enhancing the growth performance and overall health condition of farmed animals. The present study aimed to investigate the effects of two formulas of IQ extract, provided in either a powdered formula (IQ-E) or a water-soluble, granulated formula (IQ-WS) and containing the main active component sanguinarine at a concentration of 0.5% and 1%, respectively, on the growth, survival, immune response, and resistance to Vibrio parahaemolyticus infection of Pacific white shrimp (Litopenaeus vannamei). In Experiment 1, the postlarvae were divided into five groups (four replicates/group and 100 shrimp/tank) and fed four times/day for 30 days with a control feed, IQ-E at 200 or 300 mg/kg of feed, or IQ-WS at 100 or 150 mg/kg of feed. In Experiment 2, the surviving shrimp from Experiment 1 were redistributed into six groups (four treatment groups as in Experiment 1 plus the positive and negative controls with four replicates/group and 30 shrimp/tank) and challenged with V. parahaemolyticus by immersion at a concentration of 103 colony-forming units (CFU)/mL and were fed with the same diets for another 14 days. The results revealed that all IQ-fed shrimp in Experiment 1 had significantly enhanced survival rates and immune parameters (total hemocyte count and phagocytic, phenoloxidase, and superoxide dismutase activities) compared to the control group, even though the growth performances were similar across all groups. In Experiment 2, all IQ-fed groups showed better growth performance and survival rates compared to the positive control. Other than in the positive control group, no histopathological lesions in the hepatopancreas and the intestine were found. In summary, the current study demonstrated the benefits of using IQs from M. cordata as feed additives for improving the growth performance, survival rate, immune responses, and resistance to vibriosis of Pacific white shrimp.

Soybean meal (SBM) is widely used in shrimp feed agro‐industry as a fish meal (FM) replacement. However, high levels of SBM may compromise animal health as a result of nutrient imbalance. This study aimed to investigate the effects of feed enzyme combination (a mixture of 6‐phytase, serine protease, and endo‐1,3(4)‐β‐glucanase) and functional immunostimulant combination (a mixture of brewer's yeast, nucleotides, vitamin C, and vitamin E) in improving the overall health of Pacific white shrimp fed soybean‐based diet. Four diets were formulated with different amounts of SBM, FM, and poultry meal (PM): 0% SBM (with 25% FM and 12.6% PM), 30% SBM (with 12.5% FM and 5.7% PM), 30% SBM plus 0.045% feed enzymes, and 30% SBM plus 0.1% functional immunostimulants. The postlarvae were fed the test diets for 45 days. Then, the body weight, survival, FCR, Vibrio spp. count, and immune responses were analyzed. The resistance of shrimp to Vibrio parahaemolyticus infection was also evaluated. The results suggest that the diet with 30% SBM was deleterious to the shrimp's health. Feed enzymes and functional immunostimulant supplements improved overall performance, immune function, and resistance to V. parahaemolyticus infection of shrimp fed the diet containing 30% SBM compared with the 30% SBM diet without feed supplements.

Spray-dried animal plasma (SDP) in feed for several animal species provides health benefits, but research about use of SDP in shrimp feed is very limited. The objectives of the present study were to investigate the effects of dietary SDP on growth performance, feed utilization, immune responses, and prevention of Vibrio parahaemolyticus infection in Pacific white shrimp (Litopenaeus vannamei). In Experiment 1, the post-larvae were divided into five groups (four tank/group and 80 shrimp/tank) and fed four times daily diets with porcine SDP at 0, 1.5, 3, 4.5, and 6% of the diet for 45 days. In Experiment 2, the surviving shrimp from Experiment 1 were redistributed into six groups: four SDP groups as in Experiment 1 plus the positive and negative controls (four tank/group and 30 shrimp/tank). They were then challenged with V. parahaemolyticus by immersion at 105 colony-forming units (CFU)/mL and were fed with the same diets for another 4 days. In Experiment 1, shrimp fed 4.5% or 6% SDP diets had significantly higher body weight, survival rate, and improved feed conversion ratio. The immune parameters (total hemocyte count and phagocytic, phenoloxidase, and superoxide dismutase activities) of the shrimp fed 3–6% SDP diets also showed significant enhancement compared to the control. In Experiment 2, the survival rates of the 3–6% SDP groups were significantly higher than the positive control at day 4 after the immersion challenge. Likewise, the histopathological study revealed milder signs of bacterial infection in the hepatopancreas of the 3–6% SDP groups compared to the challenged positive control and 1.5% SDP groups. In conclusion, shrimp fed diets with SDP, especially at 4.5–6% of the diet, showed significant improvement in overall health conditions and better resistance to V. parahaemolyticus infection.

Asian seabass (barramundi, giant seaperch, Lates calcarifer) is a popular food fish in Asia and Australia. Native to coastal areas of the Indo-West Pacific, it can now be found from the Persian Gulf to China and northern Australia, either in coastal marine, estuarine, or freshwater habitats (Pethiyagoda & Gill, 2012;Rimmer, 2006). The Asian seabass culture technique was first developed in Thailand during the 1970s (Cheong, 1989;Rimmer, 2006). Since then, Asian seabass farming has been expanded and developed to become an economically important species in the Indo-West Pacific region.In 2020, the global production of Asian seabass from aquaculture was 117,446 tonnes. Almost 40% of this production (45,415 tonnes) was from Thailand (FAO, 2022). In Thailand, Asian seabass culture dominates the coastal aquaculture and it is the third place after tilapia (Oreochromis spp.) and clariid catfish (Clarias spp.) as the most

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