Breeding insects is already happening. But feeding the insect larvae directly to poultry as good nutrition and to improve their behavior and health is new. Just like growing those larvae on manure. According to the researchers at Wageningen University & Research (WUR), it should become the ultimate form of circularity.
All aspects of the breeding of insect larvae are investigated by WUR. From the most efficient way of rearing the larvae and the effects on the environment to the best way to use them for food and to improve animal health and welfare.
For her PhD research, Allyson Ipema uses live insect larvae, with the aim of improving the behavior, welfare and health of broilers. ‘Broilers sit a large part of the day. We want to use the live larvae to stimulate them to get moving. ‘
Good intermediate results
Based on the interim results with the broilers – a study with laying hens will follow – Ipema dares to state that feeding the larvae works out very well. ‘It is really an extra for the chicks. They love the larvae. They start looking for it and therefore move a lot more. This allows them to express their natural foraging behavior. Because the larvae are always new, they are chewable, deformable and edible. ‘
The chicks love the larvae, their behavior and welfare improve
In the first study, the larvae were sprinkled in the pen two to four times a day. The more often this happened, the more the chicks got moving. ‘But even from feeding twice a day there is a clear improvement in foraging behavior and thus animal welfare,’ adds associate professor Liesbeth Bolhuis.
Effects on paw health
In the second study, the larvae were given seven times a day or put in tubes for the chicks to take them out of. ‘The chicks were working on that for a long time,’ says Ipema. ‘It stimulated foraging behavior even more. We saw fewer effects on leg health. This may be due to the experimental set-up in which leg problems are less common anyway. More practical research will be needed in the future to further investigate this. ‘
In the first trial a clearly positive effect on paw health was found. The chicks walk more when looking for the larvae. Ipema: ‘This allows them to train their muscles and there are hardly any problems with chicks that cannot stand on their feet.’
Another effect, according to Bolhuis, is that the litter remains more loose because the chicks look several times a day for the larvae that try to hide in the litter. ‘Because the litter remains loose, wet spots are less common. Because the chicks also sit still less long, they have less skin infections on the heels. That effect will last until the end of the round. ‘
Imbalance in ration
Feeding more often a day and giving more insect larvae is better, but too often and too much is not necessary. ‘Otherwise the chicks will wait for the larvae and they will not eat enough of the supplementary feed,’ says Ipema. ‘Then you can get an imbalance in the ration’, adds researcher Dennis Oonincx. ‘From Ipema’s research and other research we know that it is possible to replace 10 percent of the feed with the larvae.’
Oonincx mainly focuses his research on the culture of the larvae. Until now, they have mainly been grown on agricultural by-products that have been approved for use as animal feed. ‘That is expensive. Growing on manure may make it cheaper and it makes more sense for the cycle concept. In the production of animal proteins such as eggs or chick meat you need protein and energy. We could then offer them in the form of larvae that can grow on the manure. ‘
Growing on pig or poultry manure works fine. ‘Fellow researchers Alejandro Parodi and Imke de Boer have already shown that the larvae prefer to eat manure than some other waste streams,’ says Bolhuis. Alejandro is also researching how growing larvae on manure can help reduce emissions of greenhouse gases, nitrogen and phosphate to the environment. Does this work better than other ways of processing manure? ‘
About 10 percent of the weight of the manure is captured by the larvae. They absorb the organic nitrogen and part of the phosphate from the manure. Oonincx: ‘We are still investigating whether we can increase this fixation, for example by also having the ammonia converted and stored. This can contribute to a more effective use of manure in the Netherlands. You can concentrate the larval manure that remains and use it as an alternative to artificial fertilizer. ‘
Using live larvae can reduce soy consumption. The costs are then somewhat higher. Oonincx estimates a few cents per egg or dimes per kilo of chick meat. ‘The question is whether that is bad. There are many positive welfare effects in return. You really have a happier chicken. And there are positive effects for the environment. That may also cost something. ‘
Finding a method for a good distribution of larvae in the house
In the study, the larvae could easily be manually distributed to the chicks. In practice, dividing by hand will not work. A good method will have to be developed to distribute larvae over the entire surface of the house in one go. If the larvae only end up in one place, it will cause unrest because the chicks or hens all suddenly want to go there. That could in turn cause welfare problems. Feeding the larvae in tubes is one of the options. These tubes must then be distributed throughout the house, so that many chicks can reach them at the same time. But spreading it loose over the entire loft seems to be the best for leg health. This can be done, for example, with funnels at several places in the barn where the larvae then hatch slowly. Another option currently being explored is to use spider feeders to spread the larvae all over the space.