Wednesday, January 13, 2016

What does a zoo nutritionist do?

Michelle Shaw is Taronga Zoo's Zoo Nutritionist. Image courtesy of Paul Fahy/Taronga Zoo.

The question of what to feed companion animals is at times controversial. Yet for the most part, there is extensive data about companion animal nutrition to draw on and plenty of options for feeding a complete diet. But who do you go to if you need to design a diet for a rare species, one for whom there may be scant or no data on nutritional requirements?

Michelle Shaw is the Zoo Nutritionist at Taronga Zoo, and one of a very, very small number of zoo nutritionists worldwide. She took some time out of her busy day to answer our questions about her career.

How did you become a zoo nutritionist?

Like a lot of people I was looking for a career that involved animals. I was not sure what was out there, I thought I was going to study to be a vet, but some early courses in animal nutrition and reproduction really piqued my interest. I had a really excellent professor who taught wildlife nutrition. After meeting him I realised that was the direction I wanted to go. I did a bachelor’s degree in animal biology. For all of my courses in nutrition I worked with Toronto Zoo. So if I was working on poultry nutrition I would do a project on emus. Or if I was working on swine nutrition I would do a project on babirusa. So I would tailor all of my classes so they had an exotic spin.

I did a Masters in animal nutrition at the University of Guelph. I ended up doing graduate work at Toronto Zoo and worked in their nutrition research area. The nutritionist there was the very first nutritionist in a zoo – they hired a nutritionist in 1974 and had a well-established department. This field is very slow growing – Toronto remains the only zoo in Canada that has a nutritionist on staff. In the US it has been growing a bit more, there are probably about two dozen nutritionists, some zoos have two or three on staff.

What are the main things you do day to day?

I’ve usually got a number of intake trials going on, and always have animals with specific goals - be it weight gain, weight loss or animals with dental issues we are trying to remedy. There might be animals with higher blood glucose, maybe not diabetes but maybe a pre-diabetic state. I am always getting feedback from keepers about how animals are eating, if their body score has changed, what their faecal condition is like. So there are animals I check on daily. There is also research for bigger things like developing new diets, so I might be involved with one particular species or a group of animals, trying to make improvements for those animals under certain circumstances, to add to the knowledge.

Or if an animal requires a post mortem and we don’t have good info on their gut, I might work with the pathologist and see what the gut looks like compared to the animal model we are using [to design a diet] for that species. So for example if we are using a cat as a model for a carnivore species, we want to see how closely related that gastrointestinal system is to that of the cat.

How do you work out what is the best thing to feed an animal?

The first thing we do is look to see what information we have on related species, so we might look at animal models. Those are always production animals, pets or laboratory animals as we know a lot about nutrient requirements for these animals. We might look at field studies but a lot of field studies in the past posed problems for zoos, as they tended to categorise an animal, for example as a frugivore, without telling us about the nutrients being eaten. A lot of the fruit we have available is higher in sugar and lower in fibre than the fruit some animals would eat in the wild.

Now studies are focusing more on the nutrients consumed. We are changing a lot of our diets based on information coming out in the last decade on protein, fat and fibre levels in diets. Some of the study designs, such as nutritional geometry, were first used to study human nutrition, but those designs are now being used on animals in zoos or their natural habitat to learn more about their nutrient requirements. 

What sort of animals do you need to advise on diet for?

Everything. From insects, such as the Lord Howe Island stick insect, up to elephants. So for an insect we might offer three different types of leaf and see how they digest these, which allows the best growth and reproductive success.

You must look at stool quite a bit?

Yes. I am quite fascinated by faecal quality. We have a number of scoring charts so keepers can score. The scoring system is on a scale of one to five, with one being very dry and five being completely liquid diarrhoea. Some of those scoring charts are like a Jackson Pollock painting! But it makes it easier for us to communicate and takes some of the guesswork out!

What can we learn about feeding companion animals from the way zoo diets are designed?

I think the difference between zoo animals and pets is that we design pellets and biscuits for a different purpose.

For zoo animals we add pellets to try to balance a diet, to make it more like what an animal would eat in the wild. We might need to add more protein or fibre to a diet.

With pets we tend to completely replace their diet with a pellet or biscuit.
There has been so much work on pet diets so we know exactly how much of each nutrient they need. We don’t have that much info from zoo animals but what we do know is zoo diets are usually too high in sugar, usually low in fibre, can be low in protein, and we need to add a biscuit to balance out what we are already feeding.

We would not what to feed the entire diet as biscuits or pellets as we are also trying to provide a diet that stimulates behaviours and occupies their time through the day.

How can food be used as enrichment in animals?

I consider every bit of food that goes into an animal’s mouth as enrichment. It’s about how we present it to them. I like to ban the bowl if possible.

There has been work done that has shown that animals will work really hard for things that may not be preferred food items. If it is put in a bowl they might not eat a cucumber, but if they have to work for it – if they have to climb a rope or hang upside down, they are more likely to eat it.

We feed to show various feeding behaviours and increase the activity of that animal. We may use larger pieces so it is not as easy for them to consume food quickly, and this encourages chewing and breaking apart food. We might spike food on trees, hide it, introduce some timed feeding device so something will pop out every once in a while.

Everything that an animal consumes is part of its enrichment, we don’t have a base diet then add enrichment items.

What are the strangest ingredients you'd incorporated into recipes?

I remember working at another zoo and we were talking about getting pangolins to eat. We talked about adding formic acid to their diets – something they would encounter in insects - which might stimulate them to eat. Sometimes we have to add things that aren’t actually nutrients to encourage food intake.

Some people might consider meal worms, maggots and pupae are strange but when they are part of an animals’ diet they are not unusual for the animals we feed. We have a great ape breaky bar we are feeding out now to increase fibre and essential fatty acids in our great apes.

Has working on animal nutrition inspired you to change your own diet?

I just feel much more guilty about the things that I eat! It definitely gives me knowledge of what I should be eating, it has made me cut a lot of sugar out of my diet from a lot of studies done on primates, but for the most part I fail miserably!

What can we do to improve the world for non-human animals?

Gather more information on the care of animals we manage.

And as part of the greater picture, it is about maintaining habitats. People think about habitat as a place for animals to live but we can’t just give them a habitat and remove their food source. We need to maintain their habitat and their natural nutrient base.

Thank you Michelle for your time. For readers interested in learning more about zoo nutrition, there are online courses such as this one. 

There are also international conferences such as the Biannual AZA NAG Conference on Zoo andWildlife Nutrition.

In addition, Michelle recommends studying animal nutrition at a tertiary institution.

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