Reading Time: 4 minutes

Housed at the University of California-Davis campus you will find a small herd of goats that have been genetically altered to produce milk that is rich with the enzyme lysozyme, found in abundance in human breastmilk. This modification was done with the hope that one day, these goats and their milk can help save lives through fighting diseases of the intestinal tract. Once they have been approved by the FDA, they will be able to move forward with their goals to increase the health of underdeveloped nations as well as here at home.

In the early 1990’s research began at UC-Davis with inserting the gene for lysozymes into mice. This soon evolved to working with goats. While the original plan was to use cows because they produce very well, it was soon realized that goats are much more common throughout the world than dairy cattle. Therefore, goats became the animal of choice in their research.

Goats as well as cattle produce very little lysozyme in their milk. Because lysozyme is one of the factors in human breastmilk that greatly affects the gut health of the infant, it was thought that bringing that enzyme more easily into the diet of those who are weaned could improve health especially when it comes to diarrheal diseases. Studies were first done with young pigs that had been inoculated with E. coli bacteria to induce diarrhea. One group was fed the lysozyme-rich milk while the other was fed unaltered goat milk. While both groups recovered, the study group which was fed the lysozyme-rich milk recovered faster, was less dehydrated, and had less damage to the intestinal tract. The study was done on pigs because their digestive tract closely resembles that of humans.

The properties of the lysozyme enzyme are not changed by processing or pasteurization. In the studies, the milk was pasteurized before use and the beneficial properties remained consistent. Even by processing into cheese or yogurt, the enzyme content stayed the same. This increases the ways in which this milk can be used to benefit people. A couple of interesting sidenotes include that the presence of the lysozyme shortened the ripening time of the cheese. Also, the milk was able to be kept at room temperature longer before bacterial growth occurred than in control groups. This gives it a longer shelf life.

Parallel studies are also being conducted on cows that have been given the gene for lactoferrin, another enzyme found in human breastmilk. This is already being produced and licensed by Pharming, Inc. Like lysozyme, lactoferrin is an enzyme with antimicrobial qualities that improves gut health.

This herd of genetically altered goats have been studied for over 20 years. Their milk contains 68% of the amount of lysozyme that human breastmilk contains. This altered gene has had no adverse effects on the goats. In fact, it has not had any unintended affects. It breeds true in the offspring, and those offspring are not adversely affected by drinking the lysozyme-rich milk. The only difference that can be detected is subtle differences of the intestinal bacteria. In studies, it was found that consuming lysozyme-rich milk increased the amounts of bacteria that are viewed as beneficial such as Lactobacilli and Bifidobacteria. There was also a decrease in the colonies of Streptococcus, Clostridia, Mycobacteria, and Campylobacteria which are associated with disease. Somatic cell count was lower. Somatic cell count is used to determine the amount of white blood cells in the milk, indicating presence of bacteria or inflammation. With a lower somatic cell count, it is suggested that even the health of the udder of the lactating goat was improved.

UC-Davis has conducted 16 research studies on the lysozyme-rich milk and the goats who produce it. The safety and efficacy have been proven, but they must still wait for FDA-approval. While that is not required to bring these animals to introduce the genetics to local herds, having FDA-approval will help others to trust this technology. There has been significant relaxation about the science of gene-editing around the world in recent years, and there is hope that governments or other organizations will assist in integrating the genetics of these goats into the local herds. This will be most easily accomplished by taking bucks that are homozygous for the gene to breed with the herds.

Researchers at UC-Davis have already partnered with teams at the University of Fortaleza and University of Ceará in Brazil to further the studies and implementation of the transgenic goats. This research is of particular interest in Brazil because their northeast region is especially plagued with early childhood deaths, many of which can be prevented by combatting intestinal ailments and malnutrition. The University of Fortaleza has a line of these transgenic goats and have been working on adapting the studies to the conditions of the Brazilian northeast region which is semi-arid.

Gene editing is becoming more common and can be used to improve nutrition and health throughout the world. Many studies are done to assure the wellbeing and health of the animals as well as safety and effectiveness of the product. These are not “Franken-goats,” just goats who now have slightly different milk qualities that can help millions of people, especially children.

---

Originally published in the July/August 2021 issue of Goat Journal and regularly vetted for accuracy.

---

References

Bailey, P. (2013, March 13). Goats’ milk with antimicrobial lysozyme speeds recovery from diarrhea. Retrieved from Ucdavis.edu: https://www.ucdavis.edu/news/goats-milk-antimicrobial-lysozyme-speeds-recovery-diarrhea#:~:text=The%20study%20is%20the%20first,infection%20in%20the%20gastrointestinal%20tract.

Bertolini, L., Bertolini, M., Murray, J., & Maga, E. (2014). Transgenic animal models for the production of human immunocompounds in milk to prevent diarrhea, malnourishment and child mortality: perspectives for the Brazilian Semi-Arid region. BMC Proceedings, 030.

Cooper, C. A., Garas Klobas, L. G., Maga, E., & Murray, J. (2013). Consuming Transgenic Goats’ Milk Containing the Antimicrobial Protein Lysozyme Helps Resolve Diarrhea in Young Pigs. PloS One.

Maga, E., Desai, P. T., Weimer, B. C., Dao, N., Kultz, D., & Murray, J. (2012). Consumption of Lysozyme-Rich Milk Can Alter Microbial Fecal Populations. Applied and Environmental Microbiology, 6153-6160.