Animal nutrition: Silkworms for pets

Professor Nadine Passlack has nurtured an interest in animal nutrition ever since she studied veterinary medicine at Hannover University of Applied Sciences. “It is very hands-on and relates directly to animal health,” she says.

Since April of last year, Passlack has held the Chair of Animal Nutrition and Dietetics at LMU. But she had already had dealings with the subject during her academic stints at Freie Universität Berlin (the Free University of Berlin) and JLU in Giessen, where she worked ahead of her move to Munich.

 The right food helps combat diseases

In the past, her research also extended to include horses and pigs. Regarding the latter, she earned her doctorate with a thesis, part of which investigated how feed affected the animals’ immune system. Today, though, her focus is on cats and dogs. “A great deal of research goes into nutrition and its positive impact on the course of diseases in pets – more than for farm animals, in many cases,” Passlack explains.

Studies of kidney diseases, for example, have shown that carefully considered feeding can improve the animals’ quality of life and longevity. In the urinary stone research with which she concerns herself, she sees the same effects: “Urinary stones are a serious condition, but one that can usually be controlled by adjusting the feed,” she notes. Nor is that all: “It is even possible to dissolve some urinary stones purely by dietetic means.”

A new source of protein for animal feed

The veterinary expert brought a project funded by the German Research Foundation (DFG) with her to LMU. The focus is on alternative protein sources in animal feed – on silkworms, to be specific. “Silkworms are by-products in the production of silk,” Passlack explains. “A few are used as fertilizers, but most are just thrown away.” But that, she argues, is not sustainable. “We also need to tap new sources of protein for animal feed to ease the burden on the environment.”

It is precisely here that her basic research comes in: “We want to find out how insect-based protein affects dogs and cats, how it influences their metabolism, their gut bacteria and their immune system.” Unlike meat, this is a protein that is unusual for animals, so the effects on their organism must be studied very carefully.

In tests, the dogs at least seemed to enjoy eating feed with this ingredient, even though a few got diarrhea as a result – which is not uncommon. “Cats are generally harder to convince,” Passlack says, recounting her experience of many past feed studies. “So, we made further minor adjustments to the feed mix for the DFG project. And then the cats liked it too.”

Impact on overweight dogs and cats

Another question she is addressing in the research project is this: What effect does silkworm protein have on overweight dogs and cats? “It is important to me to also introduce a clinical aspect to the study, and to adopt an applied approach alongside the basic research.”

Since silkworms contain a lot of interesting ingredients, the researchers working with Nadine Passlack suspect that the worms will ultimately also have a positive impact on pets’ energy balance and could make it easier for them to lose weight. Right now, they are collecting samples for the purpose of analysis. Next year, the findings are to be presented at a scientific congress and then published.

Given this work in progress, she cannot yet predict how the silkworms will affect dogs and cats. But she and a colleague are already penning an application for a second DFG project that would conduct further research into the effectiveness of silkworm protein in animal feed.

Trends in animal nutrition – Awareness is needed

Passlack is always open to new projects. Especially in the case of pet food, there are many trends such as feeding animals a fully vegetarian or vegan diet. “I get lots and lots of inquiries on the subject of nutrition,” she says. “But the data situation obviously needs more work, particularly in the context of new approaches.”

Accordingly, she advises the prospective veterinary surgeons who are her students to always stay up to date on animal nutrition so that they can provide sound advice to pet owners. “When the students move into veterinary practice, they become important points of contact regarding nutrition.”

All kinds of research possibilities

Nadine Passlack has already worked at four of the five veterinary research and training centers in Germany. “I learned a lot wherever I went! At LMU, the excellent research structures are one of the things that excites me,” she insists enthusiastically. “I have also been wonderfully well received by the students. Everything is how it should be. I feel really at home here.”