Shrimp domestication and genetic improvement programs began in the late 1980s, in the United States of America, under the United States Marine Shrimp Farming Program (USMSFP), using the Pacific whiteleg shrimp Penaeus vannamei. The USMSFP was based on proven concepts from the livestock and poultry industries and began with establishing a specific pathogen-free (SPF) shrimp stock. The original shrimp stock was obtained using rigorous screening of captured wild shrimp for selection of individuals naturally free of major shrimp pathogens. Although the concept of SPF animals was well defined for terrestrial animals, it was relatively new for aquaculture, and it took some time to be adopted by the aquaculture community. In the early 1990s, parallel to USMSFP, several other programs on genetic improvement of shrimp were initiated in Latin America. Subsequently, several new terminologies and products, such as specific pathogen resistant (SPR) shrimp, specific pathogen tolerant (SPT) shrimp and even ‘all pathogen exposed’ (APE) shrimp, entered the shrimp industry vocabulary and became commercial. This led to confusion in the shrimp industry about the meaning, relationship and significance of these new terms with respect to SPF.
The concept of specific pathogen-free (SPF) animal stocks and the technology to create and manage them evolved primarily in the Western hemisphere (the United States and Europe). It originated in the early 1940s and lies within the scope of laboratory animal medicine. Specifically, SPF chicken eggs were developed for the culture and propagation of live organisms for vaccine production. Thereafter, over the subsequent 30–40 years, SPF technology was adopted, developed and applied to commercial poultry, and in the 1960s, extended to swine and other domestic animal production systems. It was also used in veterinary applications for the production and maintenance of standardized and genetically inbred animal stocks to serve as ‘white mice’ for medical and veterinary research.
The United States Marine Shrimp Farming Program (USMSFP) of the United States Department of Agriculture (USDA) was formed in 1984, made up of several institutions in different States in the USA with the objective of increasing local production of marine shrimp while decreasing the reliance on importation. The response of USMSFP, after having its breeding program hit by a disease outbreak, was a paradigm shift towards designing, developing and implementing an integrated SPF herd health, infectious disease management program that would thereafter be applied to all the USMSFP participant institutions and eventually be commercialized in the USA shrimp industry. Consequently, the first commercial program for domestication and genetic improvement of penaeid shrimp was initiated under the USMSFP using Pacific whiteleg shrimp (Penaeus vannamei) in 1989. The primary objective of the program was to produce broodstock, free of specific pathogens, that could be bred and produce postlarvae that could be raised in biosecure production facilities and systems, to reduce mortality and increase production.
Basically, the USMSFP program adopted the breeding and selection concepts from the livestock and poultry industries to establish specific pathogen-free (SPF) stocks of shrimp that would provide high health and genetically improved postlarvae. The stocks were obtained by rigorous screening of captured, wild shrimp for selection of individuals naturally free from a list of known and easily detectable shrimp pathogens that it would be possible to permanently exclude from the stock under strict quarantine conditions in a nucleus breeding center (NBC) housing many founder families. These stocks could then be subjected to a domestication and genetic improvement program, where better-performing families from each generation could be used to produce postlarvae destined to become SPF broodstock in an adequately biosecure broodstock multiplication center (BMC). The broodstock would be supplied to commercial hatcheries where postlarvae would be produced for farmers to stock in ponds.
In parallel, several breeding and selection programs were carried out with P. vannamei in Latin America. In Venezuela, a mass selection program began in 1990 to produce shrimp adapted to the local rearing conditions. Similarly, in Colombia commercial producers mass selected TSV resistant shrimp in the early 1990s. These early efforts later developed into fully-fledged family selection breeding programs that resulted in some improved populations for the local industry. The programs in Latin America were based on the concept that the populations should be well adapted to local conditions and should be resistant or tolerant to the major disease problems endemic in the region. Thus, a major dichotomy in breeding strategies emerged in the 1990s, with selection, maintenance and multiplication of populations in essentially disease-free conditions under the SPF protocols of the USMSFP while other programs used populations selected in the presence of multiple disease pressures that are common in commercial production.
Although the concept of SPF animals was well defined for terrestrial animals that could be grown out in isolated installations, it was relatively new for aquaculture where it is difficult to isolate the animals in the aquatic environment. A major impetus for eventual wide adoption of the SPF shrimp concept was the emergence and spread of whitespot disease (WSD) of shrimp caused by whitespot syndrome virus (WSSV) in the mid-1990s. At that time, Penaeus monodon was the main cultivated shrimp species in Asia, and it was soon realized that the major source of WSSV in shrimp growout ponds was infected postlarvae derived from captured WSSV-carrying broodstock and that PCR monitoring was not sufficiently effective to minimize the level of WSSV in PLs to acceptable levels for sustainable shrimp production. As pointed out in 2005, the main reason behind the importation of P. vannamei into Asia was the perceived poor performance, slow growth rate and disease susceptibility of the major indigenous cultured shrimp species, P. chinensis in China and P. monodon virtually everywhere else. These were the consequences of using infected broodstock that would transmit pathogens to their offspring. The availability of SPF stocks of P. vannamei together with pathogen exclusion biosecurity strategy was very effective and rapidly led to it becoming the dominant cultivated shrimp species in Asia.
Because of the benefits of using domesticated and genetically improved SPF stocks of P. vannamei to produce healthy PLs for farmers to use in stocking their ponds, the term SPF in Asia began to be related to stocks with higher disease resistance or tolerance. The opposite situation occurred in Latin America where SPF shrimp were stocked in ponds with no pathogen exclusion biosecurity leading to mass mortalities and leading to farmer perception that SPF status implied higher disease susceptibility. This perception was incorrect. SPF only indicates the sanitary status of a stock and gives no indication of its susceptibility, resistance or tolerance to infection and disease.
This dichotomous approach resulted in the creation of new terms such as specific pathogen resistant (SPR) stocks and specific pathogen tolerant (SPT) stocks that led to confusion in the shrimp industry regarding the meaning, relationship and significance of these new terms with respect to SPF. While mistaken perceptions of SPF and SPR have long been recognized, the paramount need for SPF domesticated shrimp stocks and SPF as a novel and emerging technology that will support sustainable shrimp aquaculture were emphasized during the Global Conference on Aquaculture 2010.
The objective of this position paper is to clarify these concepts and terminologies and to reconfirm the importance and the benefits of developing and maintaining domesticated, healthy, shrimp stocks that are effectively free from major pathogens and make shrimp farming more profitable and sustainable. This paper reflects the outcome of an expert meeting convened by the Food and Agriculture Organization of the United Nations (FAO) in Bangkok, Thailand (May 26 to 28, 2016). The authors would like to acknowledge the Food and Agriculture Organization of the United Nations for supporting the expert group meeting that paved the way for deliberations and consensus on the subject of SPF shrimp in aquaculture.
Sources: 1. Reviews in Aquaculture. Facts, Truths and Myths About SPF Shrimp in Aquaculture. Victoria Alday-Sanz (National Aquaculture Group, P.O. Box 20, 21961, Al Lith, Saudi Arabia), James Brock, Timothy W. Flegel, Robins McIntosh, Melba Bondad-Reantaso, Marcela Salazar and Rohana Subasinghe. Early View Online Version of Record before Inclusion in an Issue. Received by Reviews in Aquaculture on April 22, 2018; accepted October 2, 2018; and first published online on November 10, 2018. 2. Bob Rosenberry, Shrimp News International, November 17, 2018.
 |
| SPF Mother Shrimp |
The United States Marine Shrimp Farming Program (USMSFP) of the United States Department of Agriculture (USDA) was formed in 1984, made up of several institutions in different States in the USA with the objective of increasing local production of marine shrimp while decreasing the reliance on importation. The response of USMSFP, after having its breeding program hit by a disease outbreak, was a paradigm shift towards designing, developing and implementing an integrated SPF herd health, infectious disease management program that would thereafter be applied to all the USMSFP participant institutions and eventually be commercialized in the USA shrimp industry. Consequently, the first commercial program for domestication and genetic improvement of penaeid shrimp was initiated under the USMSFP using Pacific whiteleg shrimp (Penaeus vannamei) in 1989. The primary objective of the program was to produce broodstock, free of specific pathogens, that could be bred and produce postlarvae that could be raised in biosecure production facilities and systems, to reduce mortality and increase production.
Basically, the USMSFP program adopted the breeding and selection concepts from the livestock and poultry industries to establish specific pathogen-free (SPF) stocks of shrimp that would provide high health and genetically improved postlarvae. The stocks were obtained by rigorous screening of captured, wild shrimp for selection of individuals naturally free from a list of known and easily detectable shrimp pathogens that it would be possible to permanently exclude from the stock under strict quarantine conditions in a nucleus breeding center (NBC) housing many founder families. These stocks could then be subjected to a domestication and genetic improvement program, where better-performing families from each generation could be used to produce postlarvae destined to become SPF broodstock in an adequately biosecure broodstock multiplication center (BMC). The broodstock would be supplied to commercial hatcheries where postlarvae would be produced for farmers to stock in ponds.
In parallel, several breeding and selection programs were carried out with P. vannamei in Latin America. In Venezuela, a mass selection program began in 1990 to produce shrimp adapted to the local rearing conditions. Similarly, in Colombia commercial producers mass selected TSV resistant shrimp in the early 1990s. These early efforts later developed into fully-fledged family selection breeding programs that resulted in some improved populations for the local industry. The programs in Latin America were based on the concept that the populations should be well adapted to local conditions and should be resistant or tolerant to the major disease problems endemic in the region. Thus, a major dichotomy in breeding strategies emerged in the 1990s, with selection, maintenance and multiplication of populations in essentially disease-free conditions under the SPF protocols of the USMSFP while other programs used populations selected in the presence of multiple disease pressures that are common in commercial production.
Although the concept of SPF animals was well defined for terrestrial animals that could be grown out in isolated installations, it was relatively new for aquaculture where it is difficult to isolate the animals in the aquatic environment. A major impetus for eventual wide adoption of the SPF shrimp concept was the emergence and spread of whitespot disease (WSD) of shrimp caused by whitespot syndrome virus (WSSV) in the mid-1990s. At that time, Penaeus monodon was the main cultivated shrimp species in Asia, and it was soon realized that the major source of WSSV in shrimp growout ponds was infected postlarvae derived from captured WSSV-carrying broodstock and that PCR monitoring was not sufficiently effective to minimize the level of WSSV in PLs to acceptable levels for sustainable shrimp production. As pointed out in 2005, the main reason behind the importation of P. vannamei into Asia was the perceived poor performance, slow growth rate and disease susceptibility of the major indigenous cultured shrimp species, P. chinensis in China and P. monodon virtually everywhere else. These were the consequences of using infected broodstock that would transmit pathogens to their offspring. The availability of SPF stocks of P. vannamei together with pathogen exclusion biosecurity strategy was very effective and rapidly led to it becoming the dominant cultivated shrimp species in Asia.
Because of the benefits of using domesticated and genetically improved SPF stocks of P. vannamei to produce healthy PLs for farmers to use in stocking their ponds, the term SPF in Asia began to be related to stocks with higher disease resistance or tolerance. The opposite situation occurred in Latin America where SPF shrimp were stocked in ponds with no pathogen exclusion biosecurity leading to mass mortalities and leading to farmer perception that SPF status implied higher disease susceptibility. This perception was incorrect. SPF only indicates the sanitary status of a stock and gives no indication of its susceptibility, resistance or tolerance to infection and disease.
This dichotomous approach resulted in the creation of new terms such as specific pathogen resistant (SPR) stocks and specific pathogen tolerant (SPT) stocks that led to confusion in the shrimp industry regarding the meaning, relationship and significance of these new terms with respect to SPF. While mistaken perceptions of SPF and SPR have long been recognized, the paramount need for SPF domesticated shrimp stocks and SPF as a novel and emerging technology that will support sustainable shrimp aquaculture were emphasized during the Global Conference on Aquaculture 2010.
The objective of this position paper is to clarify these concepts and terminologies and to reconfirm the importance and the benefits of developing and maintaining domesticated, healthy, shrimp stocks that are effectively free from major pathogens and make shrimp farming more profitable and sustainable. This paper reflects the outcome of an expert meeting convened by the Food and Agriculture Organization of the United Nations (FAO) in Bangkok, Thailand (May 26 to 28, 2016). The authors would like to acknowledge the Food and Agriculture Organization of the United Nations for supporting the expert group meeting that paved the way for deliberations and consensus on the subject of SPF shrimp in aquaculture.
Sources: 1. Reviews in Aquaculture. Facts, Truths and Myths About SPF Shrimp in Aquaculture. Victoria Alday-Sanz (National Aquaculture Group, P.O. Box 20, 21961, Al Lith, Saudi Arabia), James Brock, Timothy W. Flegel, Robins McIntosh, Melba Bondad-Reantaso, Marcela Salazar and Rohana Subasinghe. Early View Online Version of Record before Inclusion in an Issue. Received by Reviews in Aquaculture on April 22, 2018; accepted October 2, 2018; and first published online on November 10, 2018. 2. Bob Rosenberry, Shrimp News International, November 17, 2018.
Facts, Truths and Myths about SPF Shrimp
by
raMxeL
on
10:40 PM
Shrimp domestication and genetic improvement programs began in the late 1980s, in the United States of America, under the United States Mari...
