This is a nutritional tool with proven efficacy on both infectious and non-infectious branches of natural defense mechanisms.
By Stephane Ralite
Effective disease prevention strategies in shrimp farming rely on good management practices to protect environmental quality and enhance shrimp health, and a robust nutritional strategy can help maintain farmer profitability by supporting shrimp immunity. A novel yeast derivative (YANG) – specifically developed to generate a balanced immune response – confirms its benefits for overall shrimp innate immunity, leading to higher production performance (feed conversion and mortality rates). Below, we describe the latest trial results.
Balancing shrimp immune defenses
For shrimp, effective pathogen defense mechanisms include several lines of defense:
- Physical barriers (cuticle and mucus),
- Immune system (cellular and humoral),
- Antioxidant response (oxidative "stress" and detoxification), and
- Other defense systems (apoptotic response, cell death, and RNA interference).
Figure 1. Long-term and effective protection includes both infectious and non-infectious immunity.
Like all invertebrates, and in contrast to fish or terrestrial animals, shrimp do not possess an adaptive (or "memory") immune system. Therefore, classical vaccination strategies are not feasible when it comes to disease prevention. However, there are several pattern recognition receptors that can trigger different immune pathways and generate an immune response.
Long-term and effective protection includes both infectious immune responses (i.e., the ability to eliminate pathogens) and non-infectious immune responses (e.g., antioxidant protection, physical barriers) (Figure 1).
The use of functional ingredients will promote both infectious immunity and support non-infectious defense mechanisms, as well as the integrity of mucosal barriers, to ensure overall protection.
YANG (Lallemand Animal Nutrition) is based on a patented combination of complementary yeast strains with synergistic effects on the immune system, providing balanced immunomodulation.
Trials on shrimp demonstrate its benefits for both types of immune responses.
Infectious Immunomodulation
Two trials were conducted in Thailand with YANG on juvenile whiteleg shrimp (Litopenaeus vannamei) to evaluate the impact of the yeast-based functional ingredient on shrimp immune parameters in hemolymph compared to a control group.
The investigators observed:
- Increased number of immune cells in the hemolymph (total hemocyte count and large granular cells) in both trials;
- Higher phagocytic activity and melanization enzymes, as well as higher respiratory burst activity (Oz-), indicators of increased immune activity and pathogen killing processes (Figure 2);
- Significantly higher lysozyme activity, a broad-spectrum antimicrobial enzyme;
- Improved intestinal microvilli density, which is associated with gut health: digestive function and intestinal absorption capacity are preserved, and the risk of pathogen translocation is reduced (Figure 3).
Together, these data indicate that, under unchallenged conditions, YANG can support shrimp immune protection.
Non-infectious Immune Support
Another commercial trial was also conducted in Tianjin, China in 2022 on juvenile L. vannamei shrimp. The
