In the field of aquaculture, tilapia is a major player and a major contributor to global food security. However, like any farmed species, tilapia faces its share of health challenges, with diseases posing a constant threat to production.
Overall, in farming of animals, including fish, there are major efforts and trends to replace the use of antibiotics with appropriate vaccination strategies.
In the tilapia industry, vaccination has also emerged as a promising solution to mitigate disease outbreaks and ensure sustainable growth of the tilapia farming industry while addressing consumers’ concerns about antibiotics. Let’s look at where we have come from and where we are going.
Lessons from other farmed species
To understand the evolution of tilapia vaccination, we can look back at pioneering efforts in more established protein animal sectors, namely poultry and salmon:
It is interesting to compare tilapia with poultry. In fact, tilapia is often referred to as an ‘aquatic chicken’. About 250 vaccines have been developed in the poultry industry over the last 80 years. A large proportion of these vaccines are administered via the mucosal route, such as oral or intraocular spray. Given the common constraints between the tilapia and poultry industries, namely, a high number of animals to be vaccinated, it is possible that the tilapia industry may follow the same trajectory of mucosal vaccines as their application is much easier than injection vaccination.
Vaccination in the salmon industry started about 30 years ago and it has been incredibly successful at controlling most diseases. Over the years it has evolved from non-adjuvanted to adjuvanted vaccines. In addition, as additional diseases threatened the industry, vaccines evolved from monovalent to multivalent vaccines, with the most recent developments being hexavalent vaccines.
In contrast, the tilapia industry is relatively young, having been in existence for only 15 years. However, it has used this short timeframe to its advantage, notably by adopting adjuvanted vaccines since the beginning of commercial vaccine use. It has also made rapid progress by pioneering multivalent vaccines, which can currently target up to three pathogens simultaneously. This strategic approach is particularly relevant in the control of outbreaks of Streptococcus agalactiae, which presents challenges due to its multiple serotypes, especially in the first decade of vaccination in the tilapia industry.
The current reality: asymmetry in tilapia vaccine uptake
While the potential of tilapia vaccination is immense, its adoption today reveals a striking asymmetry, both between different regions and farm types. Of the approximately 150 tilapia-producing countries worldwide, only a handful have adopted commercial vaccines. In particular, countries with large, intensive lake-based tilapia operations, such as Brazil, Colombia, Honduras, Ghana, Indonesia, Malaysia and Thailand, have proactively incorporated vaccination into their disease management strategies. For example, in Brazil and Ghana, more than 50% of all tilapia produced are vaccinated. However, significant disparities remain, with smaller farms and regions often lagging behind in the adoption of vaccination routines. Indeed, it is surprising that countries such as China and Egypt, which together account for 30% of global tilapia production, vaccinate less than 1% of their farmed tilapia.
The challenges and opportunities
The challenges and opportunities of vaccination in tilapia are numerous and complex. The production system in which the fish are reared is a significant factor in determining the feasibility of vaccination. In a pond system, it is more difficult to manage the process than in a cage system. Furthermore, the size of the farm also plays a role. Smaller farms face significant barriers to adopting vaccination as a routine practice due to limited resources and technical support. Conversely, larger, integrated farms benefit from financial resources, infrastructure and technical expertise, allowing them to prioritise vaccination as a key element of disease prevention. In addition, regional dynamics play a critical role, with disease prevalence and access to resources influencing vaccine uptake. Importing countries’ and consumers’ demands for healthier food imports will also have an increasing impact. Furthermore, the lack of diagnostic resources is emerging as a significant barrier to the widespread adoption of vaccination initiatives in the tilapia sector. The unequal access to advanced diagnostic technologies exacerbates this challenge and hampers the industry’s ability to effectively identify and control specific diseases. Addressing this disparity is essential to unlock the full potential of vaccination strategies in tilapia farming.
Envisioning the future: trends and innovations
Looking ahead, the future of tilapia vaccination is very promising, drawing inspiration from successful practices in salmon and poultry farming. Anticipated trends include the development of more complex vaccines. Currently, vaccines targeting three serotypes of Streptococcus agalactiae, a major disease in tilapia, are already on the market. The future may see the development of more multivalent vaccines capable of targeting up to six pathogens simultaneously, as is the case in the salmon industry.
Furthermore, the tilapia industry is likely to undergo restructuring with the emergence of specialised segments,such as hatcheries, pre-growout farms and growout farms. In this context, pre-growout farms will vaccinate fish and sell vaccinated fingerlings. This structure will contribute to an overall higher uptake of vaccination programmes in tilapia farms. As time goes on, this trend will be reinforced by increased availability of commercial and autogenous vaccines meeting specific regional and pathogen requirements. In addition, most tilapia vaccines commercially available today are inactivated injectable vaccines. Novel technologies and new adjuvants in current development targeting mucosal immunity could contribute to the development of innovative methods of mass application, including immersion and oral vaccines. These new routes of application are expected to gain importance as efficient and practical alternatives to injection-based vaccination, leading to higher adoption of vaccination programmes and setting the course for a sustainable future.
Conclusion
As we navigate the complex landscape of tilapia vaccination, it is imperative to address the current disparities in adoption in order to ensure a more inclusive and globally resilient approach to disease management. By embracing anticipated trends and innovations, the tilapia farming industry can forge a path towards improved disease resistance, sustainable practices and a resilient future. Together, let us chart a course towards a thriving tilapia farming ecosystem where vaccination plays a central role in safeguarding the health and productivity of our aquatic resources.