A Letter From Michael Messer

(The biochemist who acted as an adviser to Geoff Smith on the formulation of Biolac)

To whom it may concern:

I have been asked by some carers for juvenile macropods to comment on a number of e-mail messages that have been recently sent. These messages contain allegations about Biolac which I think are quite wrong, as well as attacks on a person, Geoff Smith, who cannot defend himself because he is dead. Since I am the biochemist who acted as an adviser to Geoff on the formulation of Biolac, I feel it is my duty to defend both the product and Geoff against what I consider to be false allegations. I am competent to do so since I am the author or co-author of numerous scientific papers on the composition of the milk of kangaroos, wallabies and other marsupials and have had a special and long-standing interest in the problem of cataracts in joeys.

The following statements taken from these e-mails (in italics) are false or misleading :

"Biolac is not specifically made for marsupials".
The truth is that there are different Biolac products for different species, including macropods (kangaroos and wallabies), puppies, kittens and foals.

"Biolac is....not made for the major growth stages.."
The truth is that Biolac for macropods comes in three different versions (M-100, M-150 and M-200) designed for three different growth stages of these animals.

"Biolac is... made from cow's milk".
The misleading implication of this is that other milk replacers are not made from cow's milk. The truth is that almost all formulas for human infants and of milk replacers for animals (including Esbilac, DiVetelact and Wombaroo) are based on cow's milk. They are formulated by the addition of various ingredients such as whey proteins, lipids, carbohydrates, vitamins and minerals, to suit the needs of the particular species for which they are intended. The only exceptions are certain milk formulas for human infants that are based on goat milk or soy.

It is .."proven in Australia that many animals have gone blind and the only one contributing factor of all these cases is that they were reared on Biolac".
The truth is nothing of the sort. I have personally contacted carers in three different States of Australia who have been using Biolac and asked them how many of their animals have gone blind or developed cataracts. They all assured me that none of them had and that these allegation are entirely untrue. For example, Joyce Brogden of Mt. Isa, Queensland told me that she has raised at least 250 macropods on Biolac, with not one of them developing cataracts or going blind. Jan Martin of Broome, Western Australia, who has been raising macropods for at least 5 years, told a similar story. She said, however, that she has heard of some agile wallabies going blind in areas where there are many mosquitoes and there was a possibility of a mosquito-borne virus being the cause of this problem. Shirley Lack from the South Coast of NSW, who has been raising macropods and other marsupials since 1983 and has used all three products, has never had an animal develop cataracts or go blind.

"The Northern Territory did a 7 year study which proved that very young marsupials reared on Biolac have ended up blind from prolapsed lenses".
The misleading implication of this is, again, that Biolac has been proven to cause blindness in "marsupials". The truth is that these marsupials were not macropods or possums or wombats or koalas or sugar gliders but an endangered carnivorous species, the Northern Quoll (Family Dasyuridae) whose females do not have pouches. The people who did this experimental study were using Biolac in order to raise very young quolls, some weighing as little as 8 grams (about one-third of an ounce). Some of these animals, by no means all, developed cataracts, of which a few ended up with prolapsed lenses; these were exclusively the furless juveniles with eyes closed that weighed only 8-20 grams when orphaned. It would be wrong to conclude from this pioneering study that Biolac was the cause of the cataracts but it has to be remembered that the the milk of this species has never been analysed and therefore any milk replacers used for these animals may not have the correct composition. In addition it is important to note that neonatal marsupials normally receive specific maternal antibodies (immunoglobulins) from their mother's milk and that it is well-nigh impossible to provide these in any milk replacer. It is for this reason that we may never be able to hand-rear any marsupial from birth.

It had been mentioned that Geoff Smith had been a plumber and implied that he knew nothing about marsupial nutrition. The truth is that Geoff and Christine Smith had been engaged in raising orphaned marsupials for about 30 years during which time they learnt a lot about raising marsupials and about their nutrition. It is significant that Geoff was for many years an Honorary Ranger of the National Parks and Wildlide Service of NSW. Furthermore, in the year 2000, Geoff and Christine had the rare honour of being awarded the Medal of the Order of Australia in recognition of their services to the native animals of Australia.

In summary, the allegations about Biolac and Geoff Smith that are being made by others are unfounded and can be described as perverse.

A brief history on the development of milk replacers for marsupials might help readers to understand the problem of cataracts in marsupials. During the 1970s, Tanya Stephens, a Sydney veterinarian, published a number of scientific papers noting that macropod joeys raised on cow's milk suffered from diarrhoea (scouring) and opacities of the lens of the eye (cataracts). She attributed the cataracts to the galactose component of the lactose of cow's milk. This idea, however, was shown to be incorrect when it was discovered in my laboratory, at the University of Sydney, that the milk of macropods and other marsupials contains large amounts of galactose in the form of a number of unusual sugars (galacto-oligosaccharides) which are not found in the milk of placental mammals. We put forward the alternative hypothesis that the cataracts were caused by dehydration resulting from chronic diarrhoea, and that the diarrhoea was due to a reduced ability of the animals to digest and absorb lactose. In other words, that these animals have a form of lactose intolerance.

Tanya Stephens' observations led to the use of Digestelact, which was a lactose-free milk formula for human infants developed by Mr. Michael Sharpe, a Sydney food technologist. In Digestelact the lactose of cow's milk has been removed by degrading it to its constituents, glucose and galactose. Its composition is therefore similar to that of cow's milk, with the exception that the carbohydrate consists of glucose and galactose instead of lactose. Later on, a slightly modified form of Digestelact was marketed for use in animals under the name of DiVetelact. Both Digestelact and DiVetelact were successful in eliminating diarrhoea and cataracts, but carers using it usually found that the animals showed abnormally slow growth rates and had some other problems unless they were fed large volumes. These defects led to the development of Wombaroo in South Australia by Mr. Brian Rich, whose qualifications and background are unknown to me. To my knowledge he is not a biochemist and has never claimed to be one. Wombaroo did not have the problems of DiVetelact and became very popular among most, but not all carers for orphaned marsupials.

In about 1989 I got together with Dr. Don Walker, a respected animal nutritionist, to conduct a theoretical study on how good (or bad) Digestelact and Wombaroo were as milk replacers for marsupials. This effort resulted in the publication in 1992 of a 25-page article, sponsored by the Sydney University Postgraduate Committe in Veterinary Science, which noted a number of undesirable features of both products but concluded that "There is nevertheless much anecdotal evidence that both Digestelact and Wombaroo have been used with success by numerous carers for orphaned macropods and possums.". Partly as a result of this study, Geoff Smith, who I had known since about 1985, asked me to advise him on how to develop a milk replacer for macropods that might be even better than Wombaroo. The result was Biolac, which has proved to be very popular among carers. The situation now is that all three products, DiVetelact (or Digestelact), Wombaroo and Biolac, are being used in Australia. In my view none of them can be blamed for the few incidences of cataracts that have been observed over the years. It is important to note that cataracts can, theoretically at least, have many possible causes: these include dehydration, trauma to the eye, inflammation of the eye, UV light, high oxygen levels (higher than in the pouch), vitamin deficiencies, chronic hyperglycaemia as in diabetes, as well as inherited conditions such as galactosemia as found in humans, or juvenile cataracts as found in dogs and cats. Dehydration can result from diarrhoea, a fever, excessive warmth within the artificial pouch, insufficient humidity, high ambient temperatures, and increased renal solute loads due to excessive amounts of protein and/or mineral salts in the milk replacer. As mentioned, a possible cause of blindness in macropods is a virus transmitted by mosquitoes or some other insect. In 1994 to 1996 there was a massive outbreak of blindness in kangaroos in south-eastern and Western Australia which was found to be due to one or more orbiviruses, especially the Wallal virus, possibly transmitted by midges. This virus, however, affected the retina and not the lens of the eye. The relevance of this is that not all cases of blindness in macropods are due to cataracts.

(Dr.) Michael Messer, MSc, PhD
(Honorary Associate, School of Molecular and Microbial Biosciences, University of Sydney, Australia)

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