Shrimp farming has experienced exponential growth in recent years. Ecuador (1st world producer) and Mexico stand out as the main producers. Demand shows an increasingly globalised trend, with the USA, EU, Japan, and China being the largest importers.

The most cultivated species is the patiblanco shrimp or vannamei shrimp (Litopenaeus vannamei). It is native to the eastern Pacific Ocean, from the Mexican state of Sonora to northern Peru.

Mexico is currently considered the world’s second-largest producer of shrimps, closing 2021 with 227,000 metric tons, which implies an increase of 3.7% compared to 2020. The total production consists of 22% caught in bays and 78% aquaculture-farmed shrimps. Economically, shrimp farming generates USD 1 billion each year.

Sinaloa is positioned as the leading state in farm shrimp production, with a historic figure of 95,000 tonnes produced in 2021, followed by the states of Sonora and Nayarit.

Shrimp farming

Shrimp farming is carried out in coastal areas to enable more efficient use of seawater.

Furthermore, soil type, vegetation cover, continental water flow, tides, and the capacity of the waterbodies for intake and discharge are also important elements of the aquaculture farms.

The progenitors are obtained in 3 ways: they are captured, harvested on the same farm (the cycle is prolonged until sexual maturity) or obtained in specialised breeding centres. Males mature from 20 g and females from 28 g, at the age of 6 to 7 months. When they reach 30 – 45 g, they release between 100,000 and 250,000 eggs. In females, one of the eyestalks is ablated to provoke repeated cycles of maturation and spawning.

Spawning occurs at night in individual tanks or communities. After hatching, the following afternoon the nauplii are collected by the exploitation of their phototrophic behaviour.

In the hatching phase, the 4 larval stages (nauplius, zoea, mysis and postlarva) occur, which lasts between 26 and 31 days.

Once the larval stages are finished, the postlarvae are transferred to the fattening ponds. Different types of fattening techniques exist which differ mainly by the stocking density.

Shrimps are harvested at a weight of 15 to 20 g in extensive systems and 20 to 25 g in intensive systems. During the harvesting process, tanks are drained at low tide, or the water is pumped out and then cast and scoop nets, or perforated buckets are used to collect them.

Before selling, shrimps are sorted, washed, weighed and killed in iced water at 0-4˚C. They are then preserved on ice and transported to processing plants and markets.

Shrimp processing

In Mexico, shrimp is marketed in the following ways:

• Fresh/frozen shrimp in shell and with head
• Brine-fried shrimp with and without head
• Frozen shrimp with and without head
• Cooked and peeled shrimp without head
• Dried shrimp

Frozen, headless shrimp is probably the best-selling product. Once the shrimps are in the processing room, they are washed and beheaded, in this way shrimp tails are obtained, without the head and keeping the shell.The product is evaluated and classified according to its texture, colour and smell.

After sorting, the tales are packed in boxes and quickly frozen at -40 °C to preserve the product.

Finally, the frozen product is stored in chambers at -25 °C until its distribution.

Shrimp by-products

Organic fertilizer

The heads and shell are processed into a fertilizer that is used to nourish various plant species.

Chitosan

Chitin is a structural polysaccharide present in the exoskeleton of the shrimp that gives rigidity to the crustacean. This is transformed by chemical processes into chitosan, a material with various uses at the industrial level. It works as an absorbent of contaminants and food thickener. Due to its water retention capacity, the paper industry applies it in disposable handkerchiefs and diapers, as well as in photographic papers to which it provides high resistance. In the textile industry it is utilized to fix colour and prevent the shrinkage of clothing.

Dried shrimp

It is obtained by sun-drying the crustacean. The purpose is to concentrate the flavour, which is why it is used as a condiment in Asian cuisine.

Shrimp head flour

It is applied as an ingredient to make balanced feed for aquatic species.

Challenges

The shrimp industry faces many challenges, especially various diseases caused by bacteria, viruses and protozoa, as well as the environmental impact of production. Furthermore, the need for ingredients that are indispensable to meet the growing demand for aquafeed, the competition for resources, and investment problems present significant challenges as well.

In the history of shrimp farming there have been severe and periodic pandemics. Today, the industry is learning to manage and coexist with these phenomena as they emerge worldwide.

The diseases that most affect shrimp farming globally are:

• White Spot Syndrome Virus (WSSV): This is the disease that probably causes the highest direct losses in Asia and Latin America (except in Brazil and Venezuela). Mortality usually reaches 100% within two to seven days from the beginning of infection. Shrimps show characteristic white spots (inclusions), one to two millimetres in diameter, on the surface of the body, shell, and appendages.
• Yellow head virus (YHV) has been present in Asian shrimp farming, where P. monodon has become resistant. However, there is a strong possibility that YHV could cause problems in the new P. vannamei and P. stylirostris farming industries, although no cases were reported in Latin America. The infection causes inflammation of the pancreas and liver and slight yellowing. Mortality starts within a few hours and results in 100% mortality in the next 3 to 9 days. Currently, although it is present in ponds, symptoms are rarely seen.
• Taura syndrome: a widely distributed virus across the world. The first case was detected in Ecuador, from where it reached the rest of Latin America and North America within a few years, and later the Asian continent. It infects juvenile shrimps, which usually die during the moult, with a variable mortality rate between 5 and 95%. Those that survive enter the chronic phase of the disease with unique signs, such as cuticular melanized spots, which sometimes disappear during the moult.
• Vibrio type bacteria. Vibriosis causes approximately 10% of farm losses. Early mortality syndrome/acute hepatopancreatic necrosis disease (EMS/AHPND) is observed within the first thirty to forty days of the shrimp culture, eliminating up to 100% of the population in the affected pond.
• Apart from the epizootics mentioned above, effects and damage caused by diseases associated with gregarines (Nematopsis, Cephabolus and Paraophioidina) have also been reported.. Gregarines (Nematopsis, Cephabolus and Paraophioidina) cause infestation with intestinal damage that alters nutrient absorption and growth. In severe infestations, a yellowish discolouration of the intestine may be observed.

Shrimp production is criticised for its impact on the environment. The activity damages mangrove forests and marshes. Reports indicate that millions of hectares of forest disappeared, which is not only causing a modification of the landscape and the hydrological pattern, but also has an impact on the local ecosystem, as they represent the main source of organic matter in coastal areas.

Shrimp farming is facing one of the most important challenges: to reduce the amount of organic matter waste from unconsumed feed on the farms, which are dumped into the discharge water. By improving feed conversion, we can reduce this impact while improving the efficiency of the production system.

Use of pronutrients in shrimp

The reduction and prohibition of the use of antibiotics due to their impact on the environment and bacterial resistance is driving research into natural solutions. In this scenario, it is important to highlight probiotics, prebiotics, pronutrients, organic acids and salts, and brown macroalgae derivatives.

Pronutrients are complex organic molecules obtained from botanical extracts and their mechanism of action is to enhance the organic physiological response of animals. There are different types of pronutrients, each with a specific target cell.

Intestinal optimizer pronutrients have been tested to evaluate the effect on the control of gregarine infestations. They stimulate the physiological immunity of the shrimp, favouring the shrimp’s ability to control gregarines and prevent their multiplication. The control of parasitosis is expressed in improved production index (weight, feed conversion rate).

The gut-optimizer pronutrients group obtained a weighted average of 20.4 g, 8% (1.5 g) higher than the weight obtained in the control group, whose final average weight was 18.9 g.

Considering the complex challenges faced by shrimp cultures: viral diseases, management, transport, high stocking density, changes in water quality, etc., these factors will undoubtedly generate stress that affects the immune system, increasing susceptibility to diseases. This is why the use of immunostimulants is a strategy to reduce the impact of these challenges.

The use of pronutrients has achieved good results: with a reduction in mortality and a 6.97% reduction in conversion rate. This type of pronutrient boosts and stimulates the shrimp’s immune response, making it better prepared to respond to challenges and stressful situations.

Conclusion

Mexican shrimp farming is an activity with high growth potential that has seen a sustained increase in terms of productivity in recent years. It is an important food production sector that must be protected as it is necessary to cover the protein demand of a constantly growing population.

As all man-made activities, shrimp farming also has an impact on the ecosystem, which is why all available tools and technologies must be used to make shrimp farming progressively sustainable.

An outstanding strategy to improve sustainability is the use of gut-optimizer pronutrients in shrimps. It boosts the immune system to prevent infections (such as gregarins) and helps respond to different challenges. Furthermore, it improves production performance, while supporting the reduction of the environmental cost of farms.

Intestinal optimizer pronutrients are manufactured by Biovet S.A. and marketed under the name of Alquernat Zycox.