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Specific algae extracts to face immunity and mycotoxin risk challenges in aquaculture

Olmix Group shed light on scientific studies that prove specific seaweed extracts to be a real asset for producers at Aquaculture America 2020 in the US.

Olmix Group was invited to share its expertise on sustainable aquaculture at the recent Aquaculture America 2020 conference that took place in Honolulu (Hawaii) where the company put the focus on immunity and mycotoxin risk and shared recent scientific research and studies on the viability of specific marine algae extracts to tackle these main challenges for producers.

Sulphated polysaccharides to face immunity challenges of rainbow trout

By using the vast sustainable marine resources of the coast of Brittany (France) and in collaboration with several research bodies, Olmix has been able to isolate, identify and concentrate sulphated polysaccharides from the cell wall of macroalgae that have different activities to support the general health of animals. Some of these isolated polysaccharides include activities such as immunomodulation, mucin secretion and the strengthening of intestinal barrier functions.

More specifically, Olmix has recently carried out an indoor race-way system of a commercial fish farm located in São Paulo Brazil for 11 weeks (78 days) with rainbow trout species:

  • Fish were assigned to 2 treatments with 2 replicates (100 fish/tank), totalizing 400 fish. Two iso-nutritive diets, Control and Test (commercial product based on combination of green and read algal extracts), were formulated to differ only on the inclusion of 0.3% of macroalgae polysaccharides.
  • Fish were fed twice daily at 9:00 am and 4:00 pm ad libitum.
  • Hemolytic activity was improved in macroalgal sulphated polysaccharide fed trout and increased at week 11 compared to week 4 for both groups.
  • Lysozyme activity was not significant affected neither treatment of sampling week.

Olmix's conference at Aquaculture America 2020.

“These results highlight the potential effects of macroalgal sulphated polysaccharides on improving the innate immune response of skin-mucus in rainbow trout. In pursuing a more sustainable aquaculture the prevention of disease becomes an important goal. Skin-associated lymphoid tissue (SALT) has the mucus as the most significant innate response mechanism. Due to this ef­fect of mucus, pathogens are immobilized before they can adhere to or make contact with epithelial cells,” Raquel Pereira, Olmix Group’s Aqua Market Manager, said during her first conference at the event.

Improving performances under mycotoxin policontamination

The second conference of Olmix at Aquaculture America gave a deep insight on mycotoxin-related issues in the aquaculture industry, which is a topic that is being raised lately mainly due to the increasing inclusion levels of plant meals in aquafeeds.

Most mycotoxin exposure reported general clinical manifestations due to mycotoxin ingestion are related to a reduction in growth performance and in some cases alteration of blood parameters or immunosuppression. Olmix has conducted an experiment to evaluate the efficacy of an algo-clay complex (ACC) on the toxicological effects on performance on Nile tilapia (Oreochromis niloticus) fed mycotoxin policontaminated diet for 30 days.

  • Fish were assigned to 3 treatments and 4 replicates (15 fish/tank) in an indoor recirculating system. The fish were fed an isonutritive diet formulated according to the NRC (2012), using corn, soybean and meat meal, and vitaminic and mineral premixes. Raw material and experimental diets were screened for the presence of mycotoxins (aflatoxins, zearalenone, deoxynivalenol, fumonisins, diacetoxyscirpenol, T-2 Toxin and ochratoxin A) and nothing was detected.
  • Experimental diets differed only by the mycotoxins and/or ACC inclusions: T1-Control; T2-Policontanation and T-3 Policontamination+ACC. The mycotoxin policontaminated diets included aflatoxins 50 ppb, fumonisins 1000 ppb and deoxynivalenol 2000 ppb all combined. ACC was included at 2 kg/T in diet T3.
  • Body weight was recorded at day one, fifteen and thirty during the feeding trial obtained by weighing each fish individually.

Olmix has several strategies to sustainable aquaculture.

“So, the exposure to mycotoxin policontaminated diet impaired the fish growth by 6% after 30 days meanwhile the inclusion of 2 kg/T of algo-clay complex mitigated toxic effects on body weight (p= 0.0268). These results highlight the potential efficacy of algo-clay complex to mitigate the toxicity of aflatoxins, fumonisins and deoxynovalenol combined on performance of Nile tilapia. Everything suggests that toxin binders should be used in earlier stages and under challenges,” Pereira explained.

 

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