Optimizing rearing and welfare in Senegalese sole (Solea senegalesensis) broodstock: effect of ambient light intensity and handling time on stress response

Broodstock rearing conditions and handling procedures should be optimized in aquaculture species in order to benefit fish welfare and guarantee optimal conditions for spawning. In teleosts, basal cortisol levels display daily rhythms, oscillating along the 24 h of the day. In this sense, handling fish at different moments of the day may lead to different stress responses. The present study aimed at investigating the optimal rearing conditions for Senegalese sole broodstock, considering ambient light intensity and handling time. The optimal light intensity (50, 100 or 200 lx) was investigated by measuring fish cortisol levels and monitoring locomotor activity rhythms under each intensity tested. Results showed a significant increase in cortisol levels of fish exposed to 200 lx, when compared to values obtained under 100 lx, accompanied by changes in locomotor activity rhythms in both tanks under study. These results suggested that 200 lx may be too high as light intensity for this species, whereas 100 lx seems to be more adequate. Also, daily rhythms of stress response were investigated in breeders from different origins (Wild and first generation, G1). Basal cortisol levels and cortisol stress response after an acute stressor (air exposure) were monitored at two distinct moments of the day (Mid-Light and Mid-Dark). Basal levels were higher during the day in the wild group, while G1 fish seemed to have lost the daily fluctuations in basal cortisol plasma levels, as well as their daily rhythms of locomotor activity. Both groups showed lower stress responses during night-time, an indication that this is an adequate period of the day to handle this species. Senegalese sole breeders born in captivity presented more pronounced stress responses when compared to wild fish, reflecting their different life history in terms of stress challenges.FP7/SME/2008/1; UID/Multi/04326/2019; DL 57/2016/CP1361/CT0007; DL 57/2016/CP1361/CT0033info:eu-repo/semantics/publishedVersio

Effect of previous handling experiences on responses of dairy calves to routine husbandry procedures

The nature of human–animal interactions is an important factor contributing to animal welfare and productivity. Reducing stress during routine husbandry procedures is likely to improve animal welfare. We examined how the type of early handling of calves affected responses to two common husbandry procedures, ear-tagging and disbudding. Forty Holstein–Friesian calves (n = 20/treatment) were exposed to one of two handling treatments daily from 1 to 5 weeks of age: (1) positive (n = 20), involving gentle handling (soft voices, slow movements, patting), and (2) negative (n = 20), involving rough handling (rough voices, rapid movements, pushing). Heart rate (HR), respiration rate (RR) and behaviour (activity, tail flicking) were measured before and after ear-tagging and disbudding (2 days apart). Cortisol was measured at −20 (baseline), 20 and 40 min relative to disbudding time. There were no significant treatment differences in HR, RR or behaviour in response to either procedure. However, the following changes occurred across both treatment groups. HR increased after disbudding (by 14.7 ± 4.0 and 18.6 ± 3.8 bpm, positive and negative, respectively; mean ± s.e.m.) and ear-tagging (by 8.7 ± 3.1 and 10.3 ± 3.0 bpm, positive and negative, respectively). After disbudding, there was an increase in RR (by 8.2 ± 3.4 and 9.3 ± 3.4 breaths/min, positive and negative, respectively), overall activity (by 9.4 ± 1.2 and 9.9 ± 1.3 frequency/min, positive and negative, respectively) and tail flicking (by 13.2 ± 2.8 and 11.2 ± 3.0 frequency/min, positive and negative, respectively), and cortisol increased from baseline at 20 min post procedure (by 10.3 ± 1.1 and 12.3 ± 1.1 nmol/l positive and negative, respectively). Although we recorded significant changes in calf responses during ear-tagging and disbudding, the type of prior handling had no effect on responses. The effects of handling may have been overridden by the degree of pain and/or stress associated with the procedures. Further research is warranted to understand the welfare impact and interaction between previous handling and responses to husbandry procedures

Reduction of slaughterhouse stress in beef cattle by facilitating animal tameness

The relationship between animals and humans is important for animal husbandry and welfare. Loosehousing and grazing systems with low management input often result in frail relationships between humans and animals. This study investigated whether a positive handling, applied during the first days of the animals’ life, had a calming and stress reducing effect on suckler beef calves at slaughter

Targeting the Stress System During Gestation: Is Early Handling a Protective Strategy for the Offspring?

The perinatal window is a critical developmental time when abnormal gestational stimuli may alter the development of the stress system that, in turn, influences behavioral and physiological responses in the newborns. Individual differences in stress reactivity are also determined by variations in maternal care, resulting from environmental manipulations. Despite glucocorticoids are the primary programming factor for the offspring’s stress response, therapeutic corticosteroids are commonly used during late gestation to prevent preterm negative outcomes, exposing the offspring to potentially aberrant stress reactivity later in life. Thus, in this study, we investigated the consequences of one daily s.c. injection of corticosterone (25 mg/kg), from gestational day (GD) 14–16, and its interaction with offspring early handling, consisting in a brief 15-min maternal separation until weaning, on: (i) maternal behavior; and (ii) behavioral reactivity, emotional state and depressive-like behavior in the adolescent offspring. Corticosterone plasma levels, under non-shock- and shock-induced conditions, were also assessed. Our results show that gestational exposure to corticosterone was associated with diminished maternal care, impaired behavioral reactivity, increased emotional state and depressive-like behavior in the offspring, associated with an aberrant corticosterone response. The early handling procedure, which resulted in increased maternal care, was able to counteract the detrimental effects induced by gestational corticosterone exposure both in the behavioral- and neurochemical parameters examined. These findings highlight the potentially detrimental consequences of targeting the stress system during pregnancy as a vulnerability factor for the occurrence of emotional and affective distress in the adolescent offspring. Maternal extra-care proves to be a protective strategy that confers resiliency and restores homeostasis

Protein changes as robust signatures of fish chronic stress: a proteomics approach to fish welfare research

Background Aquaculture is a fast-growing industry and therefore welfare and environmental impact have become of utmost importance. Preventing stress associated to common aquaculture practices and optimizing the fish stress response by quantification of the stress level, are important steps towards the improvement of welfare standards. Stress is characterized by a cascade of physiological responses that, in-turn, induce further changes at the whole-animal level. These can either increase fitness or impair welfare. Nevertheless, monitorization of this dynamic process has, up until now, relied on indicators that are only a snapshot of the stress level experienced. Promising technological tools, such as proteomics, allow an unbiased approach for the discovery of potential biomarkers for stress monitoring. Within this scope, using Gilthead seabream (Sparus aurata) as a model, three chronic stress conditions, namely overcrowding, handling and hypoxia, were employed to evaluate the potential of the fish protein-based adaptations as reliable signatures of chronic stress, in contrast with the commonly used hormonal and metabolic indicators. Results A broad spectrum of biological variation regarding cortisol and glucose levels was observed, the values of which rose higher in net-handled fish. In this sense, a potential pattern of stressor-specificity was clear, as the level of response varied markedly between a persistent (crowding) and a repetitive stressor (handling). Gel-based proteomics analysis of the plasma proteome also revealed that net-handled fish had the highest number of differential proteins, compared to the other trials. Mass spectrometric analysis, followed by gene ontology enrichment and protein-protein interaction analyses, characterized those as humoral components of the innate immune system and key elements of the response to stimulus. Conclusions Overall, this study represents the first screening of more reliable signatures of physiological adaptation to chronic stress in fish, allowing the future development of novel biomarker models to monitor fish welfare.This study received Portuguese national funds from FCT - Foundation for Science and Technology through project UIDB/04326/2020 and project WELFISH (Refª 16–02-05-FMP-12, “Establishment of Welfare Biomarkers in farmed fish using a proteomics approach”) financed by Mar2020, in the framework of the program Portugal 2020. Cláudia Raposo de Magalhães acknowledges an FCT PhD scholarship, Refª SFRH/BD/138884/2018. Denise Schrama acknowledges an FCT PhD scholarship, Refª SFRH/BD/136319/2018.info:eu-repo/semantics/publishedVersio

Genetic analysis of immunological traits in tilapia

The immunological response to handling stress of four tilapia species is evaluated.Polymorphism is examined in genes known to influence immune response in fish

2-D strength prediction of single-row multi-bolted joints woven fabric kenaf composites

Implementation of multi-bolts arrangements in structures connections are commonplace in steel design to allow for joint efficiency and stronger connections. Woven fabric kenaf fibers are potentially used as reinforcement in composite materials due to excellent specific strength, renewability and less hazardous during handling as compared to commercial fibers. A two-dimensional Extended Finite Element Method (XFEM) framework of single-row multi-bolted joints has been developed to study the stress distribution and predict the joint bearing stress at failure. Stress distribution among adjacent bolts were compared along the hole boundary and net-tension plane, suggesting net-tension failure occurred at end-bolt. The predicted bearing strength from finite element modelling are validated against experimental framework. The testing series under investigated consists of four datasets from single-row 2 bolts and 3 bolts single-lap joints. Current study showed that the XFEM models demonstrated good agreements with the experimental results

Stress and productivity patterns of interrupted, synergistic, and antagonistic office activities.

We describe a controlled experiment, aiming to study productivity and stress effects of email interruptions and activity interactions in the modern office. The measurement set includes multimodal data for n = 63 knowledge workers who volunteered for this experiment and were randomly assigned into four groups: (G1/G2) Batch email interruptions with/without exogenous stress. (G3/G4) Continual email interruptions with/without exogenous stress. To provide context, the experiment's email treatments were surrounded by typical office tasks. The captured variables include physiological indicators of stress, measures of report writing quality and keystroke dynamics, as well as psychometric scores and biographic information detailing participants' profiles. Investigations powered by this dataset are expected to lead to personalized recommendations for handling email interruptions and a deeper understanding of synergistic and antagonistic office activities. Given the centrality of email in the modern office, and the importance of office work to people's lives and the economy, the present data have a valuable role to play

Review on the prediction of residual stress in welded steel components

Residual stress after welding has negative effects on the service life of welded steel components or structures. This work reviews three most commonly used methods for predicting residual stress, namely, empirical, semi-empirical and process simulation methods. Basic principles adopted by these methods are introduced. The features and limitations of each method are discussed as well. The empirical method is the most practical but its accuracy relies heavily on experiments. Mechanical theories are employed in the semi-empirical method, while other aspects, such as temperature variation and phase transformation, are simply ignored. The process simulation method has been widely used due to its capability of handling with large and complex components. To improve its accuracy and efficiency, several improvements need to be done for each simulation aspect of this method