According to Gram Research analysis, adding concentrated fats to pig feed significantly increases its energy value and digestibility. A 2026 study of 20 growing pigs found that adding 8% soybean oil, poultry fat, or pork fat to their diet increased net energy values to 8,139-8,222 kcal/kg compared to the control diet. Poultry fat provided the highest energy value, though all three fat sources performed similarly, suggesting farmers should choose based on cost and availability rather than nutritional differences.
Researchers tested whether adding different types of oils and fats to pig feed makes the food more nutritious and easier to digest. They fed growing pigs four different diets: one without any added fat, and three with 8% added soybean oil, poultry fat, or pork fat. All three fat sources increased how much energy the pigs could get from their food compared to the regular diet. Poultry fat provided slightly more energy than the other options. This research helps farmers and nutritionists create better pig feed formulas that give animals the right amount of nutrition.
Key Statistics
A 2026 research article with 20 growing pigs found that adding 8% poultry fat to pig feed increased net energy value to 8,222 kcal/kg, compared to 8,139 kcal/kg for soybean oil and 8,161 kcal/kg for pork fat.
According to research reviewed by Gram, all three concentrated fat sources (soybean oil, poultry fat, and pork fat) increased fat digestibility in growing pigs compared to a control diet with no added fat.
A 2026 study of 20 pigs showed that laboratory digestibility tests failed to detect differences between diets containing different fat sources, indicating that real-world testing with actual animals is more reliable than lab-only methods for evaluating fats in pig feed.
The Quick Take
- What they studied: Whether adding oils and fats (soybean oil, poultry fat, or pork fat) to pig feed increases the energy value and how well pigs can digest the food
- Who participated: 20 young male pigs that were divided into 4 groups of 5 pigs each. All pigs were the same age and type to make the comparison fair.
- Key finding: Adding any of the three fat sources increased the energy value of the feed. Poultry fat provided the most energy at 8,222 kcal/kg, compared to soybean oil at 8,139 kcal/kg and pork fat at 8,161 kcal/kg.
- What it means for you: If you raise pigs or work in animal nutrition, this research suggests that adding fats to pig feed can make it more energy-rich. However, the choice between soybean oil, poultry fat, and pork fat should also consider cost and availability, as the energy differences are relatively small.
The Research Details
Scientists divided 20 young male pigs into four equal groups of five pigs each. One group ate regular feed with no added fat (the control group), while the other three groups ate the same feed but with 8% of it replaced by either soybean oil, poultry fat, or pork fat. This setup is called a “completely randomized design,” which means each pig had an equal chance of being in any group, making the comparison fair.
The researchers measured how well the pigs digested each type of feed by collecting and analyzing their waste. They also tested the feed in laboratory conditions to see how easily it broke down. Finally, they calculated the net energy value, the actual usable energy the pigs got from each diet, using standard formulas based on digestibility data.
This approach is straightforward and practical: by testing real pigs eating real food, the results show what actually happens in farm conditions rather than just in a test tube.
Testing with real pigs eating real food is important because it shows how animals actually use different nutrients, not just how they behave in a laboratory. The researchers also used an in vitro (test tube) method to see if lab tests could predict real-world results. This helps scientists understand which testing methods are reliable for future research.
This study has several strengths: it used a controlled experimental design with equal group sizes, compared each fat source directly to a control diet, and used statistical testing (Dunnett’s test) to determine if differences were real or just due to chance. However, the study used only 20 pigs total, which is a relatively small number. The results are specific to growing pigs and may not apply to other animals or different life stages. The researchers also note that their energy estimates are specific to this particular experiment and may differ slightly if repeated with different conditions.
What the Results Show
All three fat sources, soybean oil, poultry fat, and pork fat, increased how much fat the pigs could digest compared to the control diet with no added fat. This makes sense because fats are designed to be easily absorbed by the body.
The net energy values (the actual usable energy) were highest for poultry fat at 8,222 kcal/kg, followed closely by pork fat at 8,161 kcal/kg and soybean oil at 8,139 kcal/kg. These differences are relatively small, less than 1% between the highest and lowest, suggesting that all three fat sources provide similar energy value to pigs.
Interestingly, when the researchers tested the feed in laboratory conditions (in vitro testing), they found no significant differences between the diets. This suggests that lab tests alone may not be sensitive enough to detect how different fat sources affect feed quality, and real-world testing with actual pigs is more reliable.
The study revealed that the in vitro (laboratory) digestibility test was not sensitive enough to detect the effects of adding different fats to the feed. This is important because it means scientists cannot rely solely on lab tests when evaluating how fats affect pig nutrition, they need to test with real animals to get accurate results.
This research builds on existing knowledge that fats and oils increase the energy content of animal feed. The specific energy values found in this study provide updated information that can be used in modern pig diet formulation. The finding that poultry fat provides slightly more energy than plant-based soybean oil aligns with general nutritional principles, though the difference is small enough that other factors like cost and availability may be more important in practical farming decisions.
The study used only 20 pigs, which is a relatively small number. Results from small studies can be less reliable than those from larger studies. The research was conducted under specific conditions with particular pig breeds and feed ingredients, so the results may not apply exactly to other farms or different types of pigs. The researchers also note that their energy estimates are specific to this experiment, if the study were repeated with slightly different conditions, the numbers might change somewhat. Additionally, the study only looked at growing pigs, so the results may not apply to younger piglets or adult breeding pigs.
The Bottom Line
For pig farmers and nutritionists: Adding concentrated fat sources (soybean oil, poultry fat, or pork fat) to pig feed increases its energy value and can improve pig growth and feed efficiency. Choose based on cost, availability, and local supply chains, as the energy differences between the three sources are small (less than 1%). Confidence level: Moderate to High for growing pigs specifically.
This research is most relevant to pig farmers, animal nutritionists, and feed manufacturers who formulate diets for growing pigs. It’s less directly applicable to people raising other types of animals or to those feeding pigs at different life stages (very young piglets or breeding sows). General consumers may find it interesting as background on how animal feed is optimized.
Pigs would begin showing improved growth and feed efficiency within 2-4 weeks of eating feed with added fats, though the full benefits would be most visible over the course of several weeks to months as the pigs grow. The energy boost is immediate at the metabolic level, but visible changes in pig performance take time.
Frequently Asked Questions
Does adding oil to pig feed make pigs grow faster?
Adding concentrated fats increases the energy content of feed, which can support faster growth. A 2026 study found that poultry fat, soybean oil, and pork fat all increased net energy values by similar amounts (8,139-8,222 kcal/kg), potentially improving growth efficiency when pigs consume the same amount of feed.
What type of fat is best to add to pig feed?
Research shows poultry fat provides slightly more energy (8,222 kcal/kg) than pork fat (8,161 kcal/kg) or soybean oil (8,139 kcal/kg), but differences are less than 1%. Choose based on cost and local availability rather than nutritional differences, as all three sources perform similarly.
How much fat should I add to pig feed?
This study tested adding 8% fat by replacing 8% of the regular diet. This level increased energy values without negative effects. However, optimal amounts may vary based on your specific pigs, feed ingredients, and goals, consult a nutritionist for your particular situation.
Can I test pig feed quality in a laboratory instead of with real pigs?
A 2026 study found that laboratory digestibility tests did not detect differences between feeds containing different fat sources, while real pig testing did. This suggests lab tests alone are insufficient for evaluating how fats affect feed quality, testing with actual animals provides more reliable results.
Does this research apply to all types of pigs?
This study specifically tested growing pigs. Results may not apply to very young piglets, breeding sows, or other animals. The energy values found are also specific to the experimental conditions and feed ingredients used, so they may vary slightly in different situations.
Want to Apply This Research?
- If managing pig nutrition, track weekly feed consumption (in pounds or kilograms) and pig weight gain. Compare growth rates between pigs on standard feed versus those receiving feed with added fats. Measure feed conversion ratio (weight gained per pound of feed consumed) to quantify efficiency improvements.
- Users managing pig farms could implement a feed trial: switch one group of pigs to feed containing 8% added fat (choosing based on local cost and availability) while keeping a control group on standard feed. Monitor and record weekly weights and feed consumption to see if the fat-supplemented group grows faster or more efficiently.
- Establish a baseline by tracking current feed costs and pig growth rates for 4 weeks. Then introduce fat-supplemented feed to a test group and continue tracking the same metrics for 8-12 weeks. Compare feed conversion efficiency and total growth between groups. Calculate whether the improved energy value justifies the cost of added fat in your specific situation.
This research applies specifically to growing pigs under the experimental conditions tested. Results may not apply to other animal species, different pig life stages (piglets or breeding sows), or different feed ingredients and farm conditions. Energy values are experiment-specific estimates and may vary with different conditions. Before making changes to pig feed formulation, consult with a veterinarian or animal nutritionist familiar with your specific operation. This information is for educational purposes and should not replace professional nutritional advice for your animals.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.
