Black soldier fly larvae as edible enrichment

The black soldier fly (BSFL) offers a range of opportunities for pigs, not only as a feed ingredient, but also as edible enrichment. Providing small daily portions of live BSFL to piglets after weaning has benefits for their behaviour while maintaining performance.


C Measure

Average daily gain (g/pig/day) Final weight (g)

Dry matter intake excl. BSFL (g/pig/day) Dry matter intake incl. BSFL (g/pig/day) Energy intake incl. BSFL (MJ NE/pig/day) Feed efficiency (body weight gain (g/pig)/

ommercial piglets are often abruptly weaned at an early age, when they are not yet accustomed to eat- ing solid feed. The unfamiliarity with solid feed combined with the stress piglets experience during

weaning often leads to diminished feed intake after weaning. That in turn can stall growth or even result in weight loss in the days following weaning, and is often associated with post-weaning diarrhoea. When piglets are housed in barren pens after weaning, they also tend to show manipulative be- haviours towards pen fixtures and other piglets, diminishing piglet welfare. A recent exploratory study, conducted by Wa- geningen University & Research in cooperation with Bestico, ForFarmers and HatchTech, investigated whether providing small amounts of live BSFL after weaning could ease the weaning transition and improve piglet performance and welfare after weaning.

Table 1 – Performance of piglets provided with wood shavings or live BSFL.

Period Wood shavings Live BSFL p day 0–11 day 11

208 ± 17

day 0–11 day 0–11 day 0-11 day 0–11

dry matter intake incl. BSFL (g/pig)) Energy efficiency (body weight gain (g/pig)/ day 0–11 energy intake incl. BSFL (MJ NE/pig))


9611 ± 173 215 ± 14 215 ± 14 4.7 ± 0.3

0.92 ± 0.04 84.2 ± 3.5 214 ± 14 0.79

9748 ± 189 0.79 168 ± 11 211 ± 11 5.3 ± 0.2

0.03 0.82 0.15

1.01 ± 0.04 0.13 79.8 ± 3.1 0.42

Multifunctional larvae BSFL are high in moisture, fat and protein with an amino acid profile suitable for inclusion in pig feed. Because of their high palatability and water content, they could function as a tran- sitory feed between milk and concentrate, allowing piglets to steadily get used to eating solid feed. BSFL also possess many characteristics that are generally attractive to piglets, such as being edible, odorous, manipulable and destructible. Interacting with BSFL could satisfy the motivation of piglets to explore their surroundings, thereby decreasing the ten- dency to manipulate and potentially harm other piglets. Akin to other types of enrichment materials, regular interaction with BSFL could habituate piglets to novelty, decreasing piglet fearfulness and stress.

Experimental approach In this study, 16 pairs of unfamiliar piglets were housed in pens with a wood shavings bedding, from weaning until day 11 after weaning. All piglets had ad libitum access to a pellet- ed weaner feed. In half of the pens a small amount of live BSFL (75 g on days 1–4 and 150 g on days 5–11) was scat- tered through the pen twice a day, and in the other pens a similar volume of wood shavings was scattered at the same time to control for the effect of disturbance. Piglet growth and feed intake were measured regularly. On days 2, 5 and 8 after weaning, the behaviour of all piglets was observed throughout the day, and at the end of the experi- ment all piglets were tested for their level of neophobia by introducing them to an unknown environment and an unknown object and observing their behavioural responses.

Piglet performance Table 1 shows an overview of the piglets’ performance. Pro- viding BSFL to piglets for 11 days after weaning did not affect the piglets’ daily growth or their weight at the end of the pe- riod. Visual inspection of the wood shavings in the pens indi- cated that the piglets consumed the bulk of the provided BSFL in a short period of time, which was expected because of the high palatability of the larvae. Piglets provided with BSFL did have reduced pellet intake compared with control piglets for several days after weaning, and in line with this the behavioural observations indicated that they spent less time on eating pellets.

▶ PIG PROGRESS | Volume 37, No. 7, 2021

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