Boar Taint Detection Using Parasitoid Biosensors

Abstract

The off-flavor boar taint associated with the substances skatole, androstenone, and possibly indole represents a significant problem in the pig husbandry industry. Boar taint may occur in meat from uncastrated sexually mature male pigs; consumers commonly show a strong aversion to tainted meat. Consequently, there is a need for rapid methods to sort out and remove tainted carcasses at the slaughterline. We tested the ability of wasps, Microplitis croceipes to perceive and learn the 3 boar taint compounds both individually and in combination using classical conditioning paradigms. We also established the effectiveness and reliability of boar taint odor detection when wasps were used as biosensors in a contained system called the "wasp hound" using a cohort of trained wasps. We found that the wasps are able to successfully learn indole, skatole and to also detect them when presented a 1:1:1 mixture of all 3 compounds. This was shown for both a single hand-manipulated wasp bioassay and when using the "wasp hound" detector device. In contrast, the wasps showed a weak conditioned response to androstenone at the concentration tested. The estimated gas phase concentrations that the wasps perceived during training were in the range of 10 ± 0.4 pg/s for skatole and indole, and 2 ± 0.5 pg/s for androstenone. We conclude that use of these wasps as biosensors presents a promising method for boar taint detection and discuss future training paradigms that may improve their responses to compounds such as androstenone. Practical Application: The development of a perceptive, inexpensive, and reliable means of detecting boar taint before the product is presented to sensitive consumers.

RNA Deep Sequencing Reveals Novel Candidate Genes and Polymorphisms in Boar Testis and Liver Tissues with Divergent Androstenone Levels

“…Boar taint is an off-odor and off-flavor meat trait, mainly caused by high levels of androstenone, skatole and/or indole in adipose tissue [1]. The taint has been described as being similar to urine and manure and may occur in meat from uncastrated sexually mature male pigs [2].…”

Identification of the Novel Candidate Genes and Variants in Boar Liver Tissues with Divergent Skatole Levels Using RNA Deep Sequencing

“…Notably, the most common practice to prevent this smell is the castration of male piglets. But castration is undesirable due to ethical and economical concerns [3], [4] and castration of piglets is announced to be banned in the European Community by 2018 [5] creating an urgent need to develop alternative methods to prevent tainted meat.…”

Agathis bishopi (Hymenoptera: Braconidae) as a Potential Tool for Detecting Oranges Infested with Thaumatotibia leucotreta (Lepidoptera: Tortricidae)

“…in citrus, such as Doryctobracon areolatus (Szepligeti) (Hymenoptera: Braconidae), Psytallia concolor (Szepligeti) and Utetes anastrephae (Viereck) (Hymenoptera: Braconidae) are known to locate infested fruit by responding to the volatile compounds produced by their hosts while feeding on fruit (Eben et al 2000;Benelli et al 2013;Dias et al 2014). Behavioural responses in parasitoids that indicate the presence of a host, such as crowding (where parasitoids exhibit area restricted searching) has been harnessed to develop a biosensor called the wasp hound®, which has been tested successfully (Wäckers et al 2011;Olson and Rains 2014). For example, the parasitoid Microplitis croceipes (Cresson) (Hymenoptera: Braconidae) was tested successfully as a biosensor for various chemical odours (Wäckers et al 2011;Leitch et al 2013).…”

“…Behavioural responses in parasitoids that indicate the presence of a host, such as crowding (where parasitoids exhibit area restricted searching) has been harnessed to develop a biosensor called the wasp hound®, which has been tested successfully (Wäckers et al 2011;Olson and Rains 2014). For example, the parasitoid Microplitis croceipes (Cresson) (Hymenoptera: Braconidae) was tested successfully as a biosensor for various chemical odours (Wäckers et al 2011;Leitch et al 2013). This ability of parasitoids to discriminate plants infested with their host from healthy ones, based on the nature of volatiles produced, provides a potential mechanism for developing a detection system for T. leucotreta infested fruit.…”

“…Field and laboratory studies have shown that female A. bishopi parasitoids preferably attack early instars (1st and 2nd) of T. leucotreta (Moore 2002;Gendall 2007;Zimba et al 2016), potentially before infestation symptoms are clearly visible on fruit. Understanding how A. bishopi parasitoids locate fruit infested with their host could provide a preliminary step for potential manipulation of the parasitoid as a biosensor for T. leucotreta infested fruit (Wäckers et al 2011;Olson and Rains 2014).…”