Search

The use of insects in animal feed has the potential to reduce the demand for soybean production and reduce the deforestation and loss of natural resources. In particular, the black soldier fly (BSF, Hermetia illucens) larvae have received attention due to their ability to convert organic waste into high-value biomass. Several studies have investigated the effects of providing BSF larvae to both broilers and laying hens. However, knowledge gaps regarding hens' voluntary intake of live larvae and the effects of larvae consumption on egg production still remain. Therefore, the aim of the present study was to determine the effects of the consumption of 4 different amounts of live BSF larvae on laying hen feed consumption, hen health and fearfulness, and egg production and quality. To this end, 40 Bovans White laying hens were housed individually and provided with 0, 10, 20% or ad libitum daily portions of live larvae from 18 to 30 wk of age. The larvae consumption and concentrate consumption, hen weight, egg production, and egg quality were monitored. Overall, differences were found between the hens given ad libitum access to larvae compared to the other treatments. Ad libitum hens, consumed 163 ± 41 g larvae/hen/day, consumed less concentrate (P = 0.03) and gained more weight (P = 0.0002) than all other treatments. They also had an overall higher consumption of protein, fat and energy (P < 0.03). There was no effect of larvae consumption on egg production, egg weight, shell thickness, shell breaking strength, or Haugh unit (P > 0.05). There was also no effect on hen behavior toward a novel object or in an open field test. This study is the first to provide different amounts of live BSF larvae, including an ad libitum portion to laying hens. The 20% diet could promote sustainability in the egg industry and be economically advantageous if BSF larvae can be bought in bulk for less than 40% of the cost of the concentrate., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Personality can influence how animals perceive and learn cues. The behaviour and physiological responses animals show during stressful events is indicative of their personality. Acute induced stress prior to a cognitive test are known to affect the judgement of a stimulus, but personality of an individual could also affect learning of a specific cognitive paradigm. Here, we assessed if adult laying hens' behaviour and physiological responses, as indicators of their personality, were related to their cognitive performance. We assessed their behavioural responses to a tonic immobility test, an open field test, and a manual restraint test, and measured plasma corticosterone levels after manual restraint. After that, hens (n=20) were trained in a pre-set training schedule to associate a colour-cue with a reward. In a two-choice go-go test, hens needed to choose between a baited or non-baited food container displayed randomly on the left or right side of an arena. Success in learning was related to personality, with better performance of hens which showed a reactive personality type by a long latency to walk, struggle or vocalize during the tests. Only eight out of 20 hens reached the training criteria. The non-learners showed a strong side preference during all training days. Side preferences were strong in hens with high levels of plasma corticosterone and with a long duration of tonic immobility, indicating that fearful, stress-sensitive hens are more prone to develop side biases. Our results show that learning can be hindered by side biases, and fearful animals with a more proactive personality type are more sensitive to develop such biases., (Copyright © 2016 Elsevier B.V. All rights reserved.)