Publication
Effects of Immunocastration on the Meat Quality of Bísaro Pigs
| Summary: | The use of immunocastration in extensive pig farming systems, particularly for autochthonous breeds like the Bísaro pig, presents a promising approach to enhance animal welfare and meat quality while meeting the requirements for the production of DOP products. Extensive farming practices prioritize pigs' natural behavior by providing ample space and environmental enrichment, which enhances welfare and meat quality. Within this context, immunocastration serves as an effective tool for managing pig reproduction while supporting ethical treatment. It promotes better animal welfare by avoiding surgical intervention and the associated need for pain control, thus minimizing animal discomfort. Pigs subjected to immunocastration tend to present improved behavior and greater feed efficiency. It’s also noteworthy that this method retains the favorable meat quality traits associated with entire males while mitigating the problem of boar taint, enhancing both consumer acceptance and marketability. This dual benefit helps producers maintain high meat standards without compromising animal welfare. This thesis project spanned different chapters, each one of them with a specific purpose. In chapter 3 the basal points of boar taint compounds in Bísaro pigs are reported, based on a total of 20 male pigs experiment, alotted in two groups. Both groups were raised outdoors from 4 to 13 months old, when they were slaughtered. Group Wi (n=9) was slaughtered in winter and group Su (n=11) was slaughtered in summer. Testicular morphometry, boar taint compounds, and meat quality traits such as sensory analysis and fatty acid profile were assessed. The Su group's reduced testicular volume supports a reduction of the reproductive axis during the summer. While the chemical analysis did not present significant differences in boar taint compounds, panelists perceived a heightened boar taint aroma and flavor in the Su meat. These findings suggest that Bísaro pigs exhibit reproductive seasonality. To optimize the application of immunocastration in Bísaro pigs, different protocols have been tested. Chapter 4 compares the meat quality traits in animals from three different male pigs immunocastration protocols, with two control groups consisting of surgically castrated males (SC) and boars (Bo). Two protocols started in prepubertal pigs, with two (E2) and three inoculations (L3) in the first cycle, and another in adults (A2) with only two inoculations. Meat quality traits assessed included physicochemical characteristics (pH45min and pH24h, color coordinates (L*, luminosity; a*, red-green; b*, yellow-blue; C*, chroma; and h°, hue angle), drip loss, cooking loss, shear force) and sensory appraisal, and the measurement of boar taint compounds (androstenone and skatole). Immunocastrated pigs exhibited intermediate levels of boar taint compounds, falling between surgically castrated pigs and entire males. The L3 group's results closely resembled those of the SC group, as corroborated by sensory analysis. While the other two protocols did not significantly differ from the Bo group, they exhibited a positive trend. In essence, the L3 protocol proved to be a promising alternative to surgical castration, preserving the distinctive qualities of Bísaro pig meat. Regarding female immunocastration, depicted in Chapter 5, three immunocastration protocols were tested according to their reproductive cycle. The initial immunization was carried out at two weeks post-farrowing (IM1, n=5), onset of estrus (IM2, n=5), and one-week post-estrus (IM3, n=5) followed by a booster dose four weeks after the first inoculation. A control group (C, n=5) was maintained under identical housing conditions. Morphometric evaluation of the reproductive tract was performed, along with boar taint compounds quantification (androstenone and skatole) and meat quality assessment (same parameters as chapter 4). Intact sows presented significantly heavier reproductive tracts compared to the immunocastrated sows, although no marked differences were observed in meat quality traits and boar taint compounds. Therefore, in the context of cull sows, immunocastration can be used to prevent estrus behaviors and unwanted pregnancies without compromising meat quality. Overall, immunocastration emerges as a valuable tool for improving animal welfare and meat quality in extensive pig farming systems. Further research is needed to optimize protocols and explore its potential benefits in different breeds and production systems. |
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| Main Authors: | Fontela, Sofia Coelho Botelho |
| Subject: | immunocastration meat quality boar taint compounds autochthonous pig breed |
| Year: | 2025 |
| Country: | Portugal |
| Document type: | doctoral thesis |
| Access type: | open access |
| Associated institution: | Universidade de Trás-os-Montes e Alto Douro |
| Language: | English |
| Origin: | Repositório da UTAD |
| Summary: | The use of immunocastration in extensive pig farming systems, particularly for autochthonous breeds like the Bísaro pig, presents a promising approach to enhance animal welfare and meat quality while meeting the requirements for the production of DOP products. Extensive farming practices prioritize pigs' natural behavior by providing ample space and environmental enrichment, which enhances welfare and meat quality. Within this context, immunocastration serves as an effective tool for managing pig reproduction while supporting ethical treatment. It promotes better animal welfare by avoiding surgical intervention and the associated need for pain control, thus minimizing animal discomfort. Pigs subjected to immunocastration tend to present improved behavior and greater feed efficiency. It’s also noteworthy that this method retains the favorable meat quality traits associated with entire males while mitigating the problem of boar taint, enhancing both consumer acceptance and marketability. This dual benefit helps producers maintain high meat standards without compromising animal welfare. This thesis project spanned different chapters, each one of them with a specific purpose. In chapter 3 the basal points of boar taint compounds in Bísaro pigs are reported, based on a total of 20 male pigs experiment, alotted in two groups. Both groups were raised outdoors from 4 to 13 months old, when they were slaughtered. Group Wi (n=9) was slaughtered in winter and group Su (n=11) was slaughtered in summer. Testicular morphometry, boar taint compounds, and meat quality traits such as sensory analysis and fatty acid profile were assessed. The Su group's reduced testicular volume supports a reduction of the reproductive axis during the summer. While the chemical analysis did not present significant differences in boar taint compounds, panelists perceived a heightened boar taint aroma and flavor in the Su meat. These findings suggest that Bísaro pigs exhibit reproductive seasonality. To optimize the application of immunocastration in Bísaro pigs, different protocols have been tested. Chapter 4 compares the meat quality traits in animals from three different male pigs immunocastration protocols, with two control groups consisting of surgically castrated males (SC) and boars (Bo). Two protocols started in prepubertal pigs, with two (E2) and three inoculations (L3) in the first cycle, and another in adults (A2) with only two inoculations. Meat quality traits assessed included physicochemical characteristics (pH45min and pH24h, color coordinates (L*, luminosity; a*, red-green; b*, yellow-blue; C*, chroma; and h°, hue angle), drip loss, cooking loss, shear force) and sensory appraisal, and the measurement of boar taint compounds (androstenone and skatole). Immunocastrated pigs exhibited intermediate levels of boar taint compounds, falling between surgically castrated pigs and entire males. The L3 group's results closely resembled those of the SC group, as corroborated by sensory analysis. While the other two protocols did not significantly differ from the Bo group, they exhibited a positive trend. In essence, the L3 protocol proved to be a promising alternative to surgical castration, preserving the distinctive qualities of Bísaro pig meat. Regarding female immunocastration, depicted in Chapter 5, three immunocastration protocols were tested according to their reproductive cycle. The initial immunization was carried out at two weeks post-farrowing (IM1, n=5), onset of estrus (IM2, n=5), and one-week post-estrus (IM3, n=5) followed by a booster dose four weeks after the first inoculation. A control group (C, n=5) was maintained under identical housing conditions. Morphometric evaluation of the reproductive tract was performed, along with boar taint compounds quantification (androstenone and skatole) and meat quality assessment (same parameters as chapter 4). Intact sows presented significantly heavier reproductive tracts compared to the immunocastrated sows, although no marked differences were observed in meat quality traits and boar taint compounds. Therefore, in the context of cull sows, immunocastration can be used to prevent estrus behaviors and unwanted pregnancies without compromising meat quality. Overall, immunocastration emerges as a valuable tool for improving animal welfare and meat quality in extensive pig farming systems. Further research is needed to optimize protocols and explore its potential benefits in different breeds and production systems. |
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