Feeding live Black Soldier Fly larvae (Hermetia illucens) to laying hens: effects on feed consumption, hen health, hen behaviour and egg quality

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 0.05). 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

Proceedings of the Annual Meeting of the German Branch of the World's Poultry Science Association, Dummerstorf and Rostock, Germany, March 10-11, 2020 Abstracts: The importance of the prenatal and early postnatal environment for the behavioural and physiological development of chicken

The perinatal phase, comprising the pre- and postnatal period, is a sensitive phase during which the environment can have a long-lasting impact on the individual phenotype. The long-term effects might be explained by epigenetic mechanisms, which are also involved in the transmission of experiences during (early) life to subsequent generations (Goerlich et al., 2012). It is thus no surprise that a number of studies investigate how stressors during the perinatal phase affect the development of behaviour and physiology. To measure effects of stressors on an individual, several (non-invasive) techniques have been developed. Quantification of steroid hormones, for example, is meanwhile possible in eggs, faeces, and feathers, providing promising alternatives to blood samples. Several validated behavioural tests are available to describe individual phenotypes, in the lab and on farm. Further useful techniques include thermal imaging and (prenatal) heart rate measurements (Goerlich-Jansson et al., 2019). Nevertheless, potential welfare issues due to early life experiences remain unexplored. In birds, the egg and its components (e.g. steroid hormones), and incubation conditions (e.g. light, noise) affect the development of the embryo. After hatching, the young chick is influenced by its physical and social environment, and nutrition. In the poultry industry, embryos and chicks are exposed to a variety of potential stressors during the perinatal phase. Management of parental stocks and maternal stress may affect egg composition, leading to prenatal effects on the chick’s future phenotype. Incubation conditions often do not resemble natural conditions (e.g. incubation of eggs in complete darkness), potentially resulting in abnormal behaviour (Fijn et al., 2020). Processing and transport of chicks, or nowadays of hatching eggs, may lead to stress and long-term consequences thereof. A sustainable and animal welfare friendly management of poultry should thus ideally take into account knowledge on (grand)parental stocks, egg characteristics, prenatal and early life circumstances of a chick. Acknowledgements Rebecca E. Nordquist, Gerrit van der Linde (Heering Holland), Bas Rodenbur

Developing sensor technologies to inform breeding approaches to reduce damaging behaviour in laying hens and pigs: The GroupHouseNet approach

The European COST Action GroupHouseNet aims to provide synergy for preventing damaging behaviour in group-housed pigs and laying hens. One area of focus of this network is how genetic and genomic tools can be used to breed animals that are less likely to develop damaging behaviour directed at their pen-mates. Reducing damaging behaviour in large groups is a challenge, because it is difficult to identify and monitor individual animals. With the current developments in sensor technologies and animal breeding, there is the possibility to identify individual animals, monitor individual behaviour, and link this information to the genotype. Using a combination of sensor technologies and genomics enables us to select against damaging behaviour in pigs and laying hens

No evidence for sex-specific effects of the maternal social environment on offspring development in Japanese quail (Coturnix japonica)

The social environment of reproducing females can cause physiological changes, with consequences for reproductive investment and offspring development. These prenatal maternal effects are often found to be sexspecific and may have evolved as adaptations, maximizing fitness of male and female offspring for their future environment. Female hormone levels during reproduction are considered a potential mechanism regulating sex allocation in vertebrates: high maternal androgens have repeatedly been linked to increased investment in sons, whereas high glucocorticoid levels are usually related to increased investment in daughters. However, results are not consistent across studies and therefore still inconclusive. In Japanese quail (Coturnix japonica), we previously found that pair-housed females had higher plasma androgen levels and tended to have higher plasma corticosterone levels than group-housed females. In the current study we investigate whether these differences in maternal social environment and physiology affect offspring sex allocation and physiology. Counter to our expectations, we find no effects of the maternal social environment on offspring sex ratio, sex-specific mortality, growth, circulating androgen or corticosterone levels. Also, maternal corticosterone or androgen levels do not correlate with offspring sex ratio or mortality. The social environment during reproduction therefore does not necessarily modify sex allocation and offspring physiology, even if it causes differences in maternal physiology. We propose that maternal effects of the social environment strongly depend upon the type of social stimuli and the timing of changes in the social environment and hormones with respect to the reproductive cycle and meiosi

Social environment during egg laying: Changes in plasma hormones with no consequences for yolk hormones or fecundity in female Japanese quail, Coturnix japonica

The social environment can have profound effects on an individual’s physiology and behaviour and on the transfer of resources to the next generation, with potential consequences for fecundity and reproduction. However, few studies investigate all of these aspects at once. The present study housed female Japanese quail (Coturnix japonica) in pairs or groups to examine the effects on hormone concentrations in plasma and yolk and on reproductive performance. Circulating levels of androgens (testosterone and 5-α-dihydrotestosterone) and corticosterone were measured in baseline samples and after standardised challenges to assess the responsiveness of the females’ endocrine axes. Effects of the social environment on female fecundity were analysed by measuring egg production, egg mass, fertilization rates, and number of hatched offspring. Counter to expectation, females housed in pairs had higher plasma androgen concentrations and slightly higher corticosterone concentrations than females housed in groups, although the latter was not statistically significant. Pair vs. group housing did not affect the females’ hormonal response to standardised challenges or yolk testosterone levels. In contrast to previous studies, the females’ androgen response to a gonadotropin-releasing hormone challenge was not related to yolk testosterone levels. Non-significant trends emerged for pair-housed females to have higher egg-laying rates and higher fertility, but no differences arose in egg weight or in the number, weight or size of hatchlings. We propose that our unexpected findings are due to differences in the adult sex ratio in our social treatments. In pairs, the male may stimulate female circulating hormone levels more strongly than in groups where effects are diluted due to the presence of several females. Future studies should vary both group size and sex composition to disentangle the significance of sexual, competitive and affiliative social interactions for circulating and yolk hormone levels, and their consequences for subsequent generations

Freeing the hens: Workshop outcomes for applying ethology to the development of cage-free housing systems in the commercial egg industry

Throughout the world, most laying hens producing eggs for human consumption are still kept in small, wire battery cages. Ethologists have well documented the behavioural needs of hens, and the way that battery cage confinement thwarts highly motivated behaviour and reduces hens’ quality of life. While cage-free alternatives are now being used around the world, the more challenging management in these systems has contributed to the slower than desired uptake that would be necessary for improving hens’ welfare. As part of the 2021 Interna- tional Society for Applied Ethology (ISAE) virtual conference, a workshop was held with the aim to identify solutions to the common challenges. Attendees were given information about cage-free production and then sectioned into breakout groups for discussion. Following the workshop, they were asked to participate in a short survey. Breakout sessions included the topics of stakeholder engagement and further research needs, as well as identification of solutions to the common challenges. Across the two days of the workshop, there were 80 participants, from 27 countries, mostly ethologists (both students and non-students), but including egg pro- ducers, and representatives from government and non-governmental (NGO) organizations. Of the 80 partici- pants, 35 completed the survey. Participants generated many insightful and practical ideas in both the breakout rooms and in the survey, but one particularly salient theme was that solutions already exist and what is needed is greater education and dissemination of technical knowledge (half of survey responses from participants in the developed world and 42% of ethologist’s responses fit within the theme of established producers assisting new producers or producer education and training). This was further evidenced by the noted success of cage-free producers in a variety of different geographic areas, climates, production scales and in both developed and developing regions. It was concluded that cross-sector collaboration will be necessary to speed up the transition to cage-free housing, with roles to play by the producers’ egg buying customers (retailers), end consumers, government and NGOs, and researchers. There are multiple paths forward, with many different approaches possible simultaneously, and the potential to free many more hens from their cages is promising