HERBAL MEDICATION TO IMPROVE IMMUNE DEFENCES OF FARMED FISH By: Romi Novriadi and KB Haw Romi Novriadi is Researcher at Balai Perikanan Budidaya Laut Batam, Ministry of Marine Affairs and Fisheries, Republic of Indonesia, KB Haw is Product Engineer at Aqua cultural Fresh and Marine Exploratory, Singapore Romi Novriadi
KB Haw
Today, the number of diseases as an effect of an equilibrium disruption between the hosts (animals), pathogens and environment has grown simultaneously and become a major constraint to the sustainability of aquaculture production. With changing climatic conditions and the application of (super)intensive systems, the fish become more easily succumb to diseases and will affect their survival and growth performance. Improvement of health management and husbandry practices can be proposed as an effective approach to reduce the stressful events and mortality in aquaculture system. Among the conventional treatment, the use of chemotherapy (read: antibiotics) is quite popular to treat or prevent the diseases infections. However, the frequent use of chemotherapeutic agents has stimulated the development of bacterial resistance. Another problem created by unrestricted use of antibiotics is the presence of residual antibiotics in commercialized of aquaculture products. This problem has led to allergy and toxicity in humans and resulting in shifts in the diversity of the microbiota due to the permanent existence of large amounts of antibiotics in the environment. Consequently, novel preventive approaches in aquaculture are urgently needed. In this context, the use of medicinal herbs can be used as one alternative strategy and can act as an immunostimulant, conferring early activation to the nonspecific defense mechanisms of fish and elevating the specific immune response.
Tackling Bacterial Infection In a controlled bacterial infection study with Vibrio parahaemolyticus in Tiger grouper Epinephelus fuscoguttatus, Asian Seabass Lates calcarifer and Silver pompano Trachinotus blochii, it was confirmed that 24 hours immersion with commercial herbs (AquaHerb) have been successfully provide a better resistance and survival in Tiger grouper by 82,67Âą2%, in Asian Seabass by 84.67Âą0.67 % and in Silver pompano by 88.89Âą1.39 %. According to several researcher, studies confirm that the use of purified plant extract and long term of herbal application were able to enhanced the survivability of treated fish against bacterial infection.
Figure 1. AquaHerb use at several marine fish species was able to induce survival rate against V. parahaemolyticus infection at 105 cell/ml
The beneficial effects of these commercially available AquaHerb was also strengthened by the presence of dried peat, dried Leaves Saponin and dried roots tannin in their composition. Even saponin have been reported to have damaging effect on the fish respiratory epithelia, but in low concentration, saponin based adjuvant have the unique ability to stimulate the cellmediated immune system and to enhance the antibody production. This is confirmed by Chavali reported that saponin either as crude mixtures or as a purified compounds was able to increase the immune cell proliferation. Moreover, the administration of saponin to the infected fish have been found to have a detrimental effect to protozoa, mainly due to the virucidal activity
and antifungal activity contained in their active substance. Our results are in accordance with the recent findings that indicated the prior administration of saponin contained in the AquaHerb before challenged with V. parahaemolyticus was able to enhance the Tiger grouper, Asian seabass and Silver pompano immune system in comparison to control. In addition to saponin, the use of dried tannin contained in AquaHerb was also useful for the prevention of piscine diseases and off-flavor in fish and did not harm the productive performance. Based on the field observation, the complementary of tannin and saponin will enhance their immune system and the appetite of fish after medication. However, all this benefits effects of these active substances will be only obtained if given in the appropriate dose.
Improved Cellular Immune Response The field trial also showed that AquaHerb were able to modulate some parameters of non-specific immune functions of several marine fish species. The non-specific defence mechanisms of fishes include leukocyte function, neutrophil activation, monocyte together with initiation of other inflammatory factors. The use of AquaHerb showed an elevated number of leukocyte over the whole period of the experiment in comparison to control. In the presence of V. parahaemolyticus, 24 h of AquaHerb conditioning treatment were able to significantly improved the fishes survival in comparison to other conditioning treatment. AquaHerb conditioning treatment was also able to increased total percentage of monocytes in the presence or absence of pathogen. Numbers of monocytes become more important because they act as the main cells of non-specific defense system shifts from blood cells into tissue and become macrophages that are capable to kill a variety of pathogens including bacteria.
“The result proved the efficacy of herbal immersion on the fish by reducing the number of mortality� says Prof. Harry Agusnar, Professor on Analytical Chemistry, University of Sumatera Utara. Based on the experimental results, it was obvious that the provision of herbal extract is an effective immunostimulant against bacteria from the Vibrio genus that are most frequently associated with mortalities in marine fish. The unique composition of AquaHerb added to the rearing water appear to improve the immune status and disease resistance of fish.
Figure 2. Tiger grouper Epinephelus fuscoguttatus immersed with AquaHerb for 24 hours This progress in the field of diseases treatment was further extended in February this year when the next generation of AquaHerb was investigate to overcome the virus infection in marine fish, especially to eliminate the iridovirus infection. The social campaign of using herbal medicine and avoid the use of antibiotics will be intensively performed in several Asian countries as our responsibility to support the eco-friendly of aquaculture industry and generated the healthy product for the people.