Isoquinoline alkaloids from plume poppies benefit shrimp

Plant-derived ingredients are becoming increasingly popular as feed additives in animal production, including in aquatic species. Plants can possess multiple biological activities such as antimicrobial, anti-inflammatory, antioxidant, immunostimulatory, and appetite-stimulating effects, which can affect the growth performance and health of animals.

Plant-derived isoquinoline alkaloids (IQs) are natural active components of various plants, including the pink plume poppy, a herbaceous perennial plant widely seen in China where it has long been used in traditional Chinese medicine.

Anti-inflammatory and antimicrobial properties of isoquinoline alkaloids

The main bioactive isoquinoline alkaloids, namely sanguinarine and chelerythrine, are well known for their anti-inflammatory and antimicrobial properties. According to the study, IQs are currently already considered promising feed additives to improve overall health condition and replace unnecessary antibiotic use in animal farming, and have been demonstrated in pigs, chickens and fish. These effects include growth performance enhancement, increased appetite, immunostimulation, alteration of the gut microbiome, and increased resistance to bacterial infection.

Powdered and water-soluble, granulated formulas

The study, which was conducted at the Aquaculture Business Research Center laboratory at the Faculty of Fisheries, Kasetsart University, Thailand, aimed to investigate the effects of 2 formulas of IQs extract. The extract was provided in either a powdered formula or a water-soluble, granulated formula and contained the main active component sanguinarine at a concentration of 0.5% and 1%, respectively. The effect on the growth, survival, immune response, and resistance to the Vibrio parahaemolyticus bacterial infection of Pacific white shrimp was determined.

Healthy and diseased shrimp studied

The study was divided into 2 experiments:

– Experiment 1 investigated the effects of IQs on growth, survival, and the immune system in healthy shrimp. Postlarvae were divided into 5 groups (4 replicates/group and 100 shrimp/tank) and fed 4 times/day for 30 days with a control feed, powdered formula at 200 or 300 mg/kg of feed, or the water-soluble, granulated formula at 100 or 150 mg/kg of feed.

– Experiment 2 evaluated the effects of IQs on shrimp growth, survival, and resistance to Vibrio parahaemolyticus infection. Surviving shrimp from experiment 1 were redistributed into 6 groups (4 treatment groups plus the positive and negative controls with 4 replicates/group and 30 shrimp/tank) and challenged with Vibrio parahaemolyticus by immersion at a concentration of 103 CFU/mL and were fed with the same diets for another 14 days.

Significantly enhanced survival

The researchers report that all shrimp fed the powdered formula in experiment 1 had significantly enhanced survival rates and immune parameters compared to the control group, even though the growth performances were similar across all groups. In experiment 2, all groups fed the water-soluble, granulated formula showed better growth performance and survival rates compared to the positive control.

“It is worth mentioning that only the Vibrio parahaemolyticus-infected shrimp fed IQs showed a significant improvement in body weight compared to the control group, whereas the healthy shrimp did not. These observations support the antimicrobial and anti-inflammatory hypotheses […] as the main mechanisms for the growth-promoting effect of IQs,” said the researchers, adding that isoquinoline alkaloids from plume poppies benefit shrimp and can be applied as a feed additive to support overall health condition for sustainable shrimp production.

The study was published in PLOS ONE.