Scientists tested whether liquid whey, a leftover product from cheese and yogurt making, could help pigs grow better and have healthier digestive systems. They fed some pigs regular food while others got the same food plus liquid whey. The pigs that received liquid whey gained more weight, especially in the second half of the study. Their intestines also showed signs of being stronger and healthier, with thicker protective layers and more special cells that defend against germs. This research suggests that liquid whey could be a useful and affordable way to improve animal nutrition, though more testing is needed before widespread use.

The Quick Take

  • What they studied: Whether adding liquid whey (a dairy byproduct) to pig feed would improve their growth and make their digestive systems healthier
  • Who participated: 14 young pigs split into two equal groups: one eating regular pelleted feed and one eating the same feed plus liquid whey supplement
  • Key finding: Pigs receiving liquid whey gained significantly more weight during the second half of the study and showed measurable improvements in intestinal health, including thicker intestinal walls and more protective cells
  • What it means for you: This research suggests liquid whey could be a cost-effective way to improve animal nutrition and health. However, this was a small study in pigs, so results may not directly apply to humans or other animals without further research

The Research Details

Researchers divided 14 pigs into two groups of equal size. One group ate standard pelleted feed (the control group), while the other group ate the same feed but also received liquid whey, a nutrient-rich liquid left over from dairy production. Both groups ate the same amount of food relative to their body weight. The scientists then examined the pigs’ intestines under a microscope to look for structural changes and measured specific chemicals in their gut tissue that control digestion and growth.

This type of study is called a controlled experiment because it compares two similar groups with only one difference between them—the addition of liquid whey. This design helps researchers figure out whether the whey itself caused any changes they observed.

The researchers looked at different parts of the small intestine and measured things like the height of finger-like structures (villi) that absorb nutrients, the depth of tiny pockets (crypts) where new intestinal cells are made, and the thickness of muscle layers. They also counted special protective cells called goblet cells and measured levels of three different signaling chemicals.

This approach matters because it shows exactly how a food ingredient affects the physical structure and chemical signaling of the digestive system. By looking at actual tissue under a microscope rather than just measuring weight gain, researchers can understand the mechanisms behind why an animal might grow better. This helps determine whether the benefits are real and lasting, and whether the ingredient is truly safe and beneficial for long-term use.

This study has both strengths and limitations. The strength is that it used a controlled design with a clear comparison between two groups. However, the sample size of 14 pigs is relatively small, which means results could be affected by individual variation. The study was conducted in pigs, so results may not directly transfer to other animals or humans. The research was published in a peer-reviewed journal, meaning other scientists reviewed it before publication. However, the journal’s impact factor is not provided, so we cannot assess its overall prestige in the scientific community.

What the Results Show

Pigs that received liquid whey showed significantly greater body weight gain during the second half of the experiment compared to control pigs. When researchers examined the intestines under a microscope, they found several important structural changes in the whey-fed pigs.

The finger-like projections (villi) in the ileum—the last part of the small intestine—were noticeably taller in whey-fed pigs. Taller villi mean more surface area for absorbing nutrients from food. Additionally, the tiny pockets (crypts) where new intestinal cells are produced were deeper in whey-fed pigs, suggesting faster cell turnover and renewal.

The muscle layer surrounding the intestines (called the muscularis externa) was significantly thicker in the duodenum and jejunum—the first two parts of the small intestine—in whey-fed pigs. A thicker muscle layer suggests stronger intestinal function and better movement of food through the digestive system.

Perhaps most importantly, whey-fed pigs had significantly more goblet cells throughout their intestines. These special cells produce protective mucus that shields the intestinal lining from damage and harmful bacteria. More goblet cells indicate enhanced defense mechanisms in the gut.

The researchers measured three different signaling chemicals in the intestinal tissue. Two of these chemicals—Cholecystokinin8 and Galanin—showed similar levels in both groups of pigs across all intestinal segments. However, leptin, a hormone that regulates appetite and growth, was significantly higher in the whey-fed pigs. This elevated leptin may help explain the increased growth observed in these animals, as leptin plays an important role in metabolism and body weight regulation.

This research adds to a growing body of evidence that liquid whey is a valuable nutritional resource for animals. Previous studies have shown that whey contains high-quality proteins and bioactive compounds, but detailed information about how it affects intestinal structure was limited. This study fills that gap by providing specific microscopic evidence of intestinal improvements. The findings align with the general understanding that better intestinal health supports improved growth and nutrient absorption.

Several limitations should be considered when interpreting these results. First, the study included only 14 pigs, which is a small sample size. Larger studies would provide more confidence in the findings. Second, the experiment was conducted only in pigs, so we cannot assume the same results would occur in humans or other animal species without additional research. Third, the study examined pigs at a specific point in time; longer-term studies would help determine whether these benefits persist over extended periods. Fourth, the researchers did not measure actual nutrient absorption or digestive efficiency, only structural changes. Finally, the study did not examine potential negative effects or optimal dosage levels of liquid whey supplementation.

The Bottom Line

Based on this research, liquid whey appears to be a promising supplement for improving pig growth and intestinal health (moderate confidence level). The evidence suggests it may enhance nutrient absorption capacity and strengthen the gut’s natural defenses. However, because this is a single small study in animals, these findings should not be considered definitive. More research is needed, particularly longer-term studies and research in other species, before making widespread recommendations.

This research is most relevant to livestock farmers, animal nutritionists, and agricultural scientists interested in improving pig production using sustainable, cost-effective ingredients. It may also interest dairy producers looking for valuable uses for whey byproducts. Pet owners and people interested in human nutrition should note that this study was conducted in pigs, and results do not automatically apply to humans or companion animals without further research.

Based on this study, the benefits of liquid whey supplementation appeared during the second half of the experimental period, suggesting that an adaptation period is necessary before seeing growth improvements. Intestinal structural changes likely develop gradually over weeks rather than days. Realistic expectations would be to observe noticeable growth differences over several weeks of consistent supplementation, though individual variation would occur.

Want to Apply This Research?

  • If tracking animal nutrition, users could log weekly weight measurements and body condition scores for animals receiving whey supplementation, comparing them to a control group to monitor growth rate differences over time
  • Users managing livestock could implement a structured whey supplementation protocol by adding measured amounts of liquid whey to feed at consistent times daily, tracking intake amounts and animal response through the app
  • Establish a long-term tracking system that records weekly weight gain, feed conversion efficiency, and any visible changes in animal health or coat condition, allowing users to assess whether whey supplementation provides meaningful benefits for their specific animals

This research was conducted in pigs and describes changes in animal intestinal tissue. These findings do not directly apply to human nutrition or health without additional research. If you are considering whey products for human consumption or animal feeding, consult with a healthcare provider, veterinarian, or animal nutritionist. This summary is for educational purposes and should not replace professional medical or veterinary advice. Individual results may vary based on numerous factors including age, health status, and overall diet.