Researchers tested whether a charcoal-based additive called biochar could prevent an unpleasant odor that develops in pork from some male pigs. They fed biochar to 100 male pigs from two different breeding lines for four weeks and tracked chemical levels in their blood and fat. The results showed that biochar worked well for many pigs—especially those with lower natural steroid production—but worked better in some genetic lines than others. This research suggests biochar could be a gentler alternative to castration, though scientists need to do more work to predict which pigs will benefit most from the treatment.

The Quick Take

  • What they studied: Whether adding charcoal (biochar) to pig feed could prevent an unpleasant smell that sometimes develops in pork meat from male pigs.
  • Who participated: 100 male pigs from two different breeding companies. The pigs started the study at about 75 kg body weight and were fed the charcoal supplement for four weeks, then monitored for two more weeks without it.
  • Key finding: Biochar successfully prevented the bad smell in 67-89% of pigs that normally would develop it, depending on their genetic line. Pigs with lower natural steroid production responded especially well to the treatment (100% success rate).
  • What it means for you: This research suggests biochar could become a humane alternative to castration for preventing pork odor problems. However, scientists still need to figure out which pigs will respond best before this becomes a standard farm practice. This is early-stage research that shows promise but needs more testing.

The Research Details

Scientists divided 100 male pigs into two groups based on their breeding genetics. All pigs received a diet containing 5% biochar (a special type of charcoal) for four weeks, starting when they weighed about 75 kg. After the four-week treatment period, the biochar was removed from their diet for two more weeks. Throughout the study, researchers took blood samples weekly and fat samples every two weeks to measure specific chemicals related to the bad smell problem. They also tracked how much the pigs grew and how efficiently they converted food to body weight.

The researchers also classified each pig based on its natural ability to produce certain steroid hormones. They measured a hormone called estrone sulfate in the blood to determine if each pig had ‘high’ or ’low’ steroid production capacity. This classification helped them understand whether a pig’s natural hormone production affected how well the biochar treatment worked.

This approach allowed the scientists to test whether biochar worked equally well across different pig genetics and whether a pig’s natural steroid production ability could predict treatment success.

Understanding how biochar works in different types of pigs is important because farms use many different breeding lines. If biochar only worked in certain genetic lines, it would limit its usefulness. By testing two different breeding companies’ pigs, the researchers could see if the treatment was broadly applicable. Additionally, identifying which pigs respond best to biochar (based on steroid production) could help farmers use the treatment more efficiently and cost-effectively.

This study has several strengths: it included a reasonable sample size (100 pigs), tested two different genetic lines to check if results were consistent, measured multiple relevant chemicals in blood and fat, and included a recovery period after treatment to see if effects lasted. However, the study was relatively short (six weeks total) and focused on one farm setting. The results are promising but represent early-stage research that would benefit from larger, longer studies across multiple farms to confirm these findings.

What the Results Show

The biochar treatment worked differently depending on the pig’s genetics. Among pigs from one breeding company (PIC), 71% never developed the bad smell at all, and of those that did develop it, 67% responded well to biochar treatment. For pigs from the other breeding company (AGC), 47% never developed the smell, but 89% of those that did develop it responded to biochar treatment.

When researchers looked at steroid production capacity, they found a striking pattern: pigs with low steroid production capacity responded extremely well to biochar (100% success rate). In contrast, pigs with high steroid production capacity that didn’t respond to biochar treatment were exclusively from the high-steroid group—meaning no high-steroid pigs failed to respond if they were going to respond at all.

Interestingly, the two genetic lines showed similar chemical levels in blood and fat, even though they responded differently to treatment. This suggests that the genetic differences affecting treatment response are subtle and not reflected in the basic chemical measurements the researchers took.

Growth performance (how much pigs gained and how efficiently they converted food) was mostly similar between the two genetic lines. However, pigs from the PIC line showed slightly better feed efficiency during the biochar treatment period and faster growth during the recovery period. These differences were small and unlikely to be practically important on a farm. The fact that biochar treatment didn’t negatively affect growth is important because it means the treatment wouldn’t slow down pig development.

Previous research had already shown that biochar could reduce the bad smell in pork, but this study extends that work by testing whether the treatment works equally well across different pig genetics. The finding that steroid production capacity predicts treatment response is new and builds on earlier observations. This research confirms that biochar is a viable approach and adds important information about which pigs are most likely to benefit.

The study was relatively short (six weeks), so researchers couldn’t determine if the benefits lasted long-term after treatment stopped. The study was conducted at one location with one set of environmental conditions, so results might differ on other farms or in different climates. The sample size of 100 pigs, while reasonable, is modest for drawing very strong conclusions. Additionally, the researchers identified that steroid production capacity predicts treatment response but couldn’t explain why this relationship exists or identify the specific genetic markers involved. More research is needed to understand the biological mechanisms and to validate these findings in larger, longer studies.

The Bottom Line

Based on this research, biochar appears to be a promising treatment for preventing bad pork smell in male pigs, particularly those with lower steroid production capacity. However, this is early-stage research, and biochar treatment is not yet standard practice on farms. Farmers interested in this approach should: (1) recognize that it works better in some pigs than others, (2) understand that additional research is needed to identify which pigs will respond best, and (3) consult with veterinarians and genetics specialists before implementing this on their farms. The confidence level for this recommendation is moderate—the results are encouraging but need confirmation in larger studies.

This research is most relevant to pig farmers and the pork industry, particularly those concerned about animal welfare (since biochar could reduce the need for castration). Veterinarians and animal scientists working with swine should follow this research. Consumers concerned about how pigs are raised may also be interested in this potential alternative to castration. This research is NOT directly applicable to humans or other animals at this time.

In this study, biochar treatment lasted four weeks and appeared to work during that period. However, researchers don’t yet know how long the benefits last after treatment stops or whether repeated treatments would be necessary. Realistic expectations would be that if this becomes a farm practice, it would take several years of additional research before it becomes widely adopted.

Want to Apply This Research?

  • If you’re a farmer or agricultural professional, track the percentage of pigs in your herd that develop boar taint and monitor how many respond to biochar treatment if you implement it. Measure plasma estrone sulfate levels (a blood hormone marker) to classify pigs as high or low steroid producers, then compare treatment response rates between these groups.
  • For farmers considering this approach: (1) Work with your veterinarian to establish baseline rates of boar taint in your herd, (2) Consider implementing a pilot program with biochar supplementation in a small group of pigs to test effectiveness on your farm, (3) Measure growth performance to ensure biochar doesn’t negatively impact pig development, and (4) Track which pigs respond best to identify patterns that might help predict treatment success.
  • Establish a long-term tracking system that monitors: (1) the percentage of pigs developing boar taint before and after biochar treatment, (2) blood hormone levels (estrone sulfate) to classify steroid production capacity, (3) growth rates and feed efficiency to ensure treatment doesn’t harm performance, and (4) cost-effectiveness compared to current castration practices. Review this data quarterly to determine if biochar treatment is working effectively on your specific farm.

This research is preliminary and represents early-stage investigation into biochar as a treatment for boar taint in pigs. The findings have not yet been widely validated across different farms, climates, or management systems. Farmers should not implement biochar treatment as a standard practice without consulting veterinarians and animal scientists. This research is specific to pigs and should not be applied to other animals or humans. Individual results may vary based on genetics, environment, and farm management practices. Always consult with qualified agricultural professionals before making changes to animal feeding or management practices.