Better bottled milk could be on the cards for Australia’s best-loved ‘bears.’ A study which examines how koala milk changes over time could lead to the production of nutritionally advanced formula milk for the country’s orphaned joeys.
It’s hoped the research, published in the International Journal of Biological Macromolecules, will assist koala rehabilitation and conservation.
Koalas aren’t bears. They’re marsupials; mammals that give birth to tiny, under-developed babies, which then continue to grow in the safety of their mother’s pouch. Milk is vital to their development. “A healthy pouch environment, together with nutrition and immune protection from its mother’s milk, is essential for a joey’s growth and survival,” says Manujaya W. Jayamanna Mohottige from Australia’s Edith Cowan University.
After a gestation of around 34 days, the kidney bean-sized joey then spends over a year consuming its mother’s milk. During this time, it transforms from something that looks like a foetus into something that looks like a koala. Researchers already knew that the mother’s milk changes during this time, but the new study zooms in on the detail.
Using samples taken from seven lactating females, researchers studied how the composition of koala milk changes from early (birth to 120 days) to mid (up to 270 days) to late (up to 400 days) lactation. The most abundant proteins, which included caseins and albumin, were consistently detected across all stages, reflecting their crucial roles in nutrition, immune function and breaking down eucalyptus leaf toxins. Levels of other proteins changed over time.
“We were able to identify and quantify the proteins at each key lactation stage,” says Mohottige. “Early milk plays a key role in protecting the joey, mid-stage milk may help protect the brain during its fastest growth, and later milk has a composition reflecting the joey’s increasing independence.”
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Koalas are listed as ‘vulnerable.’ They are threatened by habitat loss, disease, climate change and bushfires. According to the Australian Koala Foundation, thousands of koalas are rescued, treated and cared for every year. This includes joeys, many of which need to be hand-reared and bottle-fed.
A deeper understanding of koala milk could help scientists develop improved milk substitutes for orphaned joeys. Current koala formula lacks marsupial-specific and bioactive milk proteins. “Matching milk replacers to the natural shifts we see in koala milk could greatly help hand-reared joeys grow and thrive,” says Michelle Colgrave, also from Edith Cowan University.
Top image credit: slowmotiongli/Getty Images
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