In Vitro Rearing Changes Social Task Performance and Physiology in Honeybees

In vitro rearing of honeybee larvae is an established method that enables exact control and monitoring of developmental factors and allows controlled application of pesticides or pathogens. However, only a few studies have investigated how the rearing method itself affects the behavior of the resulting adult honeybees. We raised honeybees in vitro according to a standardized protocol: marking the emerging honeybees individually and inserting them into established colonies. Subsequently, we investigated the behavioral performance of nurse bees and foragers and quantified the physiological factors underlying the social organization. Adult honeybees raised in vitro differed from naturally reared honeybees in their probability of performing social tasks. Further, in vitro-reared bees foraged for a shorter duration in their life and performed fewer foraging trips. Nursing behavior appeared to be unaffected by rearing condition. Weight was also unaffected by rearing condition. Interestingly, juvenile hormone titers, which normally increase strongly around the time when a honeybee becomes a forager, were significantly lower in three- and four-week-old in vitro bees. The effects of the rearing environment on individual sucrose responsiveness and lipid levels were rather minor. These data suggest that larval rearing conditions can affect the task performance and physiology of adult bees despite equal weight, pointing to an important role of the colony environment for these factors. Our observations of behavior and metabolic pathways offer important novel insight into how the rearing environment affects adult honeybees.

Experimental Evaluation of δ2H, δ13C and δ15N Variability in Blood and Feathers of Wild and Captive Birds: Implications for Interspecific Food Web Studies

Stable-hydrogen (δ2H), nitrogen (δ15N), and carbon (δ13C) isotopes are used to decipher broad movement patterns and trophic relationships among diverse species, and an improved understanding of factors controlling natural variation in tissue-isotope measurements will enhance these applications. To evaluate the rearing environment and family-related effects on the isotopic composition of tissues, we cross-fostered nestling tree swallows (Tachycineta bicolor, Vieillot 1808) and American kestrels (Falco sparverius, Linnaeus 1758) by swapping recently hatched birds (<4 days old) among nest boxes and collecting blood and feathers prior to fledging. To assess developmental effects, we measured δ2H in blood and feathers of captive mallard (Anas platyrhynchos, Linnaeus 1758) ducklings challenged energetically during growth. Stable isotope composition was not strongly related to nest box type or natal nest (i.e., family of origin) effects in swallows and kestrels; tissue-isotope composition was related to rearing environment, indicative of differences in nest and parental quality or parental provisioning tactics. Blood and feather δ2H values in swallows were positively related to antecedent maximum ambient temperature, and unrelated to elevated energy expenditure in mallards. The average differences between δ2H in blood and feathers were similar for nestling swallows (27‰, 32‰; two sites) and mallards (26‰, 30‰; two age groups), and lower than in nestling kestrels (50‰). Strong species-specific patterns in blood-feather differences were not observed for δ15N and δ13C in swallows or kestrels; divergent δ2H results may be related to differences in nest ambient conditions, diet composition, or physiological processes affecting hydrogen assimilation during growth and feather synthesis. In swallows, tissue-isotope values reflected parental prey selection from spatially distinct food webs during nestling development with little effect(s) of family of origin, egg composition, or early growth.

Development of Social Skills in Kindergarten: A Latent Class Growth Modeling Approach

Social skills acquired during early childhood are often the foundation for success later in life. Using a nationwide survey dataset in Japan, this study aims to explore the multiple growth trajectories of social skills among children in kindergarten by using a latent class growth modeling approach. It also examines whether, and to what extent, the home-rearing environment at early age predict trajectories of social skills development. Children in this study were assessed on social skills at three waves, four home-rearing environment dimensions (human stimulation, social stimulation, avoidance of punishment, and social support for parenting) and demographic background were measured at wave 1. The results indicated that three distinct growth trajectories of social skills existed during kindergarten: high increase levels, moderate increase levels, and decreased levels. The avoidance of punishment and children’s gender significantly predicted the growth trajectories of social skills. Thus, the results suggest that more attention should be paid to the home-rearing environment and boys.

Early environmental enrichment and impoverishment differentially affect addiction-related behavioral traits, cocaine-taking, and dopamine D2/3 receptor signaling in a rat model of vulnerability to drug abuse

Rationale Risk factors for drug addiction include genetics, environment, and behavioral traits such as impulsivity and novelty preference (NP), which have been related to deficits in striatal dopamine (DA) D2/3-receptors (D2/3R) and heightened amphetamine (AMPH)-induced DA release. However, the influence of the early rearing environment on these behavioral and neurochemical variables is not clear. Objectives We investigated the influence of early rearing environment on striatal D2/3R availabilities and AMPH-induced DA release in relation to impulsivity, NP, and propensity to drug self-administration (SA) in “addiction-prone” Roman high- (RHA) and “addiction-resistant” Roman low-avoidance (RLA) rats. Methods Animals were reared post-weaning in either environmental enrichment (EE) or impoverishment (EI) and were assessed at adulthood for impulsivity, NP, and propensity to cocaine SA. EE and EI rats were also scanned using single-photon emission computed tomography to concurrently measure in vivo striatal D2/3R availability and AMPH-induced DA release. Results EE vs. EI was associated with heightened impulsivity and a lack of NP in both rat lines. Higher dorsal striatal D2/3R densities were found in RHA EE and higher AMPH-induced DA release in RLA EE. Both impulsivity and NP were negatively correlated to dorsal striatal D2/3R availabilities and positively correlated with AMPH-induced DA release in EI but not in EE. EE vs. EI was related to a faster rate of cocaine intake and elevated active timeout responses in RHAs. Conclusion Our results suggest non-monotonic, environment-dependent, relationships between impulsivity, NP, and D2/3R-mediated signaling, and suggest that EI vs. EE may decrease the reinforcing effects of psychostimulants in predisposed individuals.

BIOCHEMICAL RESPONSES AND GENETIC EXPRESSIONS OF SYNTHETIC COMMON CARP POPULATIONS EXPOSED TO HIGH-AMMONIA REARING ENVIRONMENT

Carp is one of the leading freshwater aquaculture commodities in Indonesia. Further improvement of carp strains by the Research Institute for Fish Breeding (RIFB), Sukamandi, Indonesia, has produced a synthetic F2 carp. The strain is assembled from different strains of carps and has shown better growth and health characteristics. Considering that high environmental ammonia (HEA) has affected most carp grow-out systems, this study aimed to determine the performance of the synthetic carp populations in a high ammonia rearing environment. The treatments were rearing media of the synthetic carp seed populations added with and without (control) 200 mg/L NH4Cl arranged in three replicates. A total of 30 fish seeds/aquarium, weighed 10-15 g/fish, was used in the study. Dissolved oxygen levels were maintained above 2 mg/L using aeration. This study shows that higher tolerant carp populations had red blood cells of 232.66 ± 17.24 cells/mL, indicating a direct effect of high ammonia on red blood cell count (p<0.05). Cortisol levels of 80.90 ± 6.35 ng/mL in resistant carp indicate significant differences (p<0.05). The relative expressions of the HSP70 gene in the liver (Log10) ranged between 0.72 and 2.80. The values demonstrate that high ammonia-resistant synthetic carp have a higher relative expression ratio of the HSP70 gene than the less resistant group. This research concluded that the populations of synthetic F2 carp showed a degree of resistance against high-ammonia rearing conditions. When it is ready for aquaculture, this synthetic carp strain could be farmed in high density using intensive systems in HEA-affected artificial lakes and reservoir

Rearing Environment and Longitudinal Brain Development in the Pig

Objectives Artificial rearing of pigs provides a number of advantages over conventional rearing (i.e., true maternal care), including careful control of nutrient intake and environment conditions. Yet there remains a gap in knowledge when comparing brain development between sow-reared and artificially-reared domestic pigs. Thus, our research sought to model brain development and assess recognition memory in a longitudinal manner by directly comparing rearing environments. Methods Forty-four intact (i.e., not castrated) male pigs were artificially-reared or sow-reared from postnatal day 2 until postnatal week 4. After postnatal week 4, all pigs were housed in a group setting within the same environment until postnatal week 24. Magnetic resonance imaging was conducted on pigs at 8 longitudinal time-points to model developmental trajectories of brain macrostrutural and microstructural outcomes. Additionally, pigs behavior were tested using the novel object recognition task at postnatal weeks 4 and 8. Results Throughout the 24-week study, no differences between rearing groups were noted in weekly body weights, average growth and feed intake patterns, or feed efficiency. Whole brain, grey matter, white matter, and cerebrospinal fluid growth patterns also did not differ between pigs assigned to different early-life rearing environments. Moreover, minimal differences in regional absolute volumes and fractional anisotropy developmental trajectories were identified, though artificially-reared pigs exhibited higher initial rates of myelination in multiple brain regions compared with sow-reared pigs. Furthermore, behavioral assessment at both PNW 4 and 8 suggested little influence of rearing environment on recognition memory, however, an age-dependent increase in object recognition memory was observed in the sow-reared group. Conclusions Our findings suggest that early-life rearing environment has little influence on brain growth trajectories and behavior in the domestic pig. Artificial rearing may promote maturation in certain brain areas but does not appear to elicit long-term effects in outcomes including brain structure or behavior. Funding Sources The study was funded by Société des Produits Nestlé SA.

Maternal Genotypes and Mother-Infant Attachment As Moderators Of The Association Between The Early Rearing Environment And Cortisol Secretion

Background: This dissertation examines maternal genotypes and mother-infant attachment as moderators of the association between the early rearing environment and cortisol secretion. Study 1 examines whether DRD2, SLC6A3, and OXTR genes moderate the association between maternal history of care and maternal cortisol secretion. Study 2 examines mother-infant attachment as a moderator of the associations between maternal depressive symptoms and both infant and maternal cortisol secretion. Method: Mothers self-reported their history of care and depressive symptoms at infant age 16 months. At 17 months, mother-infant attachment was assessed in the Strange Situation Procedure (SSP). Salivary cortisol was assessed at baseline and at 20- and 40-minutes post-SSP. Buccal cells were collected for genotyping. Results: Study 1 revealed that maternal history of low care predicts elevated cortisol secretion, but only for mothers with 10-repeat alleles of SLC6A3 or G alleles of OXTR. Study 2 revealed that maternal depressive symptoms predict elevated cortisol secretion, but only for infants and mothers in non-secure attachment relationships. Conclusions: This dissertation enhances our understanding of the complex relations between the early rearing environment and maternal and infant cortisol secretion.

Maternal Genotypes and Mother-Infant Attachment As Moderators Of The Association Between The Early Rearing Environment And Cortisol Secretion

Background: This dissertation examines maternal genotypes and mother-infant attachment as moderators of the association between the early rearing environment and cortisol secretion. Study 1 examines whether DRD2, SLC6A3, and OXTR genes moderate the association between maternal history of care and maternal cortisol secretion. Study 2 examines mother-infant attachment as a moderator of the associations between maternal depressive symptoms and both infant and maternal cortisol secretion. Method: Mothers self-reported their history of care and depressive symptoms at infant age 16 months. At 17 months, mother-infant attachment was assessed in the Strange Situation Procedure (SSP). Salivary cortisol was assessed at baseline and at 20- and 40-minutes post-SSP. Buccal cells were collected for genotyping. Results: Study 1 revealed that maternal history of low care predicts elevated cortisol secretion, but only for mothers with 10-repeat alleles of SLC6A3 or G alleles of OXTR. Study 2 revealed that maternal depressive symptoms predict elevated cortisol secretion, but only for infants and mothers in non-secure attachment relationships. Conclusions: This dissertation enhances our understanding of the complex relations between the early rearing environment and maternal and infant cortisol secretion.