Positive welfare effects of physical enrichments from the nature-, functions- and feeling- based approaches in farmed rainbow trout (Oncorhynchus mykiss)

Brunet, Valentin; Kleiber, Aude; Patinote, Amélie; Pierre-Lô, Sudan; Duret, Cécile; Gourmelen, Guillaume; Moreau, Emmanuelle; Fournel, Catherine; Pineau, Lionel; Calvez, Ségolène; Milla, Sylvain; Colson, Violaine

doi:10.1016/j.aquaculture.2021.737825

Cited by 23 publications

(35 citation statements)

References 79 publications

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“…For example, rearing conditions where welfare was supposed to be good were linked to greater motivation to explore in fish tested for emotional reactivity 41 . Also, in a recent study, rainbow trout previously reared in a complex and stimulating habitat spent more time exploring the new environment when subjected to the novel-tank test and exhibited less erratic swimming compared to fish reared under standard conditions 42 . This suggests that good welfare conditions may lead to bold phenotypes and lower fearfulness measured in the novel-tank test.…”

Section: Discussionmentioning

confidence: 90%

Positive effects of bubbles as a feeding predictor on behaviour of farmed rainbow trout

Kleiber

Le-Calvez

Kernéis

et al. 2022

Sci Rep

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Occupational enrichment emerges as a promising strategy for improving the welfare of farmed animals. This form of enrichment aims to stimulate cognitive abilities of animals by providing them with more opportunities to interact with and control their environment. Predictability of salient daily events, and in particular predictability of feeding, is currently one of the most studied occupational enrichment strategies and can take several forms. In fish, while temporal predictability of feeding has been widely investigated, signalled predictability (based on a signal, such as light or sound) has received little attention. Depending on the type of predictability used and the ecology of the species, the effects on fish welfare often differ. The present study aimed to determine which feeding predictability would be most appropriate for rainbow trout, the main continental farmed fish in Europe, and what the consequences might be for their welfare. We tested four feeding predictability conditions: temporal (based on time of day), signalled (based on bubble diffusion), temporal + signalled (based on time and bubble diffusion), and unpredictable (random feeding times). Behavioural and zootechnical outcomes recorded were swimming activity, aggressive behaviours, burst of accelerations, and jumps, emotional reactivity, and growth. Our results showed that rainbow trout can predict daily feedings relying on time and/or bubbles as predictors as early as two weeks of conditioning, as evidenced by their increased swimming activity before feeding or during feed omission tests, which allowed to reinforce their conditioned response. Temporal predictability alone resulted in an increase in pre-feeding aggressive behaviours, burst of accelerations, and jumps, suggesting that the use of time as the sole predictor of feedings in husbandry practices may be detrimental to fish welfare. Signalled predictability with bubbles alone resulted in fewer pre-feeding agonistic behaviours, burst of accelerations, and jumps than in the temporal predictability condition. The combination of temporal and signalled predictability elicited the highest conditioned response and the level of pre-feeding aggression behaviours, burst of accelerations and jumps tended to be lower than for temporal predictability alone. Interestingly, fish swimming activity during bubble diffusion also revealed that bubbles were highly attractive regardless of the condition. Rainbow trout growth and emotional reactivity were not affected by the predictability condition. We conclude, therefore, that the use of bubbles as a feeding predictor could represent an interesting approach to improve rainbow trout welfare in farms, by acting as both an occupational and physical enrichment.

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Section: Discussionmentioning

confidence: 90%

Positive effects of bubbles as a feeding predictor on behaviour of farmed rainbow trout

Kleiber

Le-Calvez

Kernéis

et al. 2022

Sci Rep

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“…However, as previously discussed, both these and other proposed measures require further research and validation [ 23 , 24 ]. Recently, an investigation in farmed rainbow trout ( Oncorhynchus mykiss ) used a nature-, functions- and feelings-based approach to validate the positive welfare effects of environmental enrichment for the fish, where nature refers to the promotion of natural behaviours, function refers to the maintenance of biological functions and feelings being the stimulation of exploration and curiosity [ 25 ]. Validation of the resource provisions stipulated in the Good Life Framework should be the focus of future work.…”

Section: Discussionmentioning

confidence: 99%

Advancing a “Good Life” for Farm Animals: Development of Resource Tier Frameworks for On-Farm Assessment of Positive Welfare for Beef Cattle, Broiler Chicken and Pigs

Rowe

Mullan

2022

Animals

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There is increasing recognition that farm animal welfare standards should ensure positive welfare, as well as prevent negative welfare. Resources that are valued by an animal and that provide opportunities to engage in motivated behaviours can elicit positive physical and emotional states and therefore positive welfare and a “good life” for farmed animals. Evaluation of resource provision is considered the best way of assessing positive welfare at present, in the absence of validated and practical animal-based measures. Previous research has outlined a framework of three tiers of increasingly positive welfare (Welfare +, Welfare ++, Welfare +++) containing resources that incrementally increase the opportunities for a good life over and above the requirements of UK law and code of practice. Based on this blueprint, “Good Life Frameworks” were developed for beef cattle, broiler chickens and pigs, containing resources that increase good life opportunities according to the scientific literature and expert consultation. We describe the initial development of these frameworks, including a piloting exercise with the UK farm assurance industry, to further refine the frameworks according to auditor and farmer feedback, and test the frameworks as a method of on-farm assessment and assurance of a “good life” for farm animals.

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“…The present study, complementing our previous work [ 14 ], aims to investigate the molecular mechanisms at the cerebral level underlying the EE’s beneficial effects in trout reared in an aquaculture system. In order to reveal the brain’s regulatory pathways and networks involved in the environmental effects on fish cognition, we used a high-throughput microfluidics quantitative polymerase chain reaction (qPCR) system (Biomark microfluidic system; Fluidigm, San Francisco, USA) to analyze numerous genes’ expressions in specific areas of the trout brain (forebrain, hypothalamus, and hindbrain).…”

Section: Introductionmentioning

confidence: 96%

“…Recently, we highlighted important behavioral differences between rainbow trout ( Oncorhynchus mykiss ) juveniles reared in EE with physical enrichments (PVC pipes, plastic plants, and white stones) for three months and those held in barren environment (BE) [ 14 ]. When observed in their rearing tanks, enriched fish displayed more shoal cohesion and fewer agonistic and/or stereotypic behaviors.…”

Section: Introductionmentioning

confidence: 99%

“…Among these species, trout is the main continental fish species produced in Europe (European Commission, 2020), so it deserves more attention, especially for finding strategies to alleviate welfare issues caused by low-stimulating environments often encountered in farming systems. Understanding the neural mechanisms underlying the behavioral effects of EE, which we previously reported in trout [ 14 ], would highlight the brain-plasticity mechanisms involved and provide new insight into the benefits of this practice in farmed fish.…”

Section: Introductionmentioning

confidence: 99%

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Physical Enrichment Triggers Brain Plasticity and Influences Blood Plasma Circulating miRNA in Rainbow Trout (Oncorhynchus mykiss)

Cardona

Brunet

Baranek

et al. 2022

Biology

Self Cite

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Physical enrichment is known to improve living conditions of fish held in farming systems and has been shown to promote behavioral plasticity in captive fish. However, the brain’s regulatory-mechanism systems underlying its behavioral effects remain poorly studied. The present study investigated the impact of a three-month exposure to an enriched environment (EE vs. barren environment, BE) on the modulation of brain function in rainbow trout (Oncorhynchus mykiss) juveniles. Using high-throughput RT-qPCR, we assessed mRNA genes related to brain function in several areas of the trout brain. These included markers of cerebral activity and plasticity, neurogenesis, synaptogenesis, or selected neurotransmitters pathways (dopamine, glutamate, GABA, and serotonin). Overall, the fish from EE displayed a series of differentially expressed genes (neurotrophic, neurogenesis, and synaptogenesis markers) essentially localized in the telencephalon, which could underpin the beneficial effects of complexifying the environment on fish brain plasticity. In addition, EE significantly affected blood plasma c-miRNA signatures, as revealed by the upregulation of four c-miRNAs (miR-200b/c-3p, miR-203a-3p, miR-205-1a-5p, miR-218a-5p) in fish blood plasma after 185 days of EE exposure. Overall, we concluded that complexifying the environment through the addition of physical structures that stimulate and encourage fish to explore promotes the trout’s brain function in farming conditions.

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Positive welfare effects of physical enrichments from the nature-, functions- and feeling- based approaches in farmed rainbow trout (Oncorhynchus mykiss)

Abstract: Positive welfare effects of physical enrichments from the nature-, functionsand feeling-based approaches in farmed rainbow trout (Oncorhynchus mykiss

Cited by 23 publications

References 79 publications

Positive effects of bubbles as a feeding predictor on behaviour of farmed rainbow trout

Positive effects of bubbles as a feeding predictor on behaviour of farmed rainbow trout

Advancing a “Good Life” for Farm Animals: Development of Resource Tier Frameworks for On-Farm Assessment of Positive Welfare for Beef Cattle, Broiler Chicken and Pigs

Physical Enrichment Triggers Brain Plasticity and Influences Blood Plasma Circulating miRNA in Rainbow Trout (Oncorhynchus mykiss)

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