What is enrichment?Environmental enrichment isclosely related to behavioural enrichment. It is an animal husbandry principlethat aims to enhance the quality of life of captive animals. It provides andidentifies stimuli for necessary psychological and physiological well-being. (Shepherdson, Mellen, Hutchins, 1998).
Environmental enrichment aims to improve or maintain an animal’s health byincreasing the number of species- specific behaviour, and also increasingpositive utilisation of the captive environment. Its aim is to prevent or reduceabnormal behaviour, as well as enhancing an animal’s ability to cope withcaptivity. A paper that shows this is Environmental Enrichment Reduces A? Levelsand Amyloid Deposition in Transgenic Mice. The researchers used anexperimental paradigm, they called environmental enrichment. Lazarou et al first exposed maletransgenic mice to an enriched environment. Secondly, they experimented withsteady levels of soluble and formic acid – soluble A? peptides. They werereduced in enriched mice compared to standard housing mice. Western blotanalyses showed enrichment does not alter APP processing but alters levels ofaccumulated A? peptides.
Several critical approaches were noted in theexperimental approaches when compared to Jankowskyet al (2003). Thirdly, they showed the activity of A? – degrading proteaseand neprilysin is elevated in enriched mice. Lastly they employed high –density oligonucleotide arrays which showed elevation in the endothelial cellactivated in enriched mice.
(Lazarov etal., 2005)Robert Young believed people involved in environmentalenrichment should have a basic understanding of animal welfare. Robert Young mentioned two definitionsof environmental enrichment. Environmental enrichment describes howenvironments of animals in captivity can change for the benefit of the animals.Young used this definition from Shepherdson, 1994. However Young also used this definition from BHAG, 1999 provided by Valerie Hare.
The definition statesenvironmental enrichment is a process for improving zoo environments and carefor the animals. It is a dynamic process with changes to structure andhusbandry practices with the aim to increase behavioural choices and drawingout species behaviours and abilities. (Young,2013)Mason et al stated stereotypic behaviours in some captive wildanimals are well known in zoos and similar institutions. Wild captive speciesneed to be taken seriously and in terms of enrichment which can lead to centralnervous system dysfunction. Stereotypic behaviours may be expressed in animalsto cope with sub-optimal environments.
They are only expressed when naturalactivities are not available. Mason et alargued that the best welfare option is to provide appropriate enrichmentsthat animals can choose to interact with. Abnormal repetitive behaviour mayindicate a risk to cross-species, suggesting enrichment changes to the root ofthe problem. Habitats that induce abnormal repetitive behaviour can be poorerthan those which do not. Animals within sub-optimal environments can farebetter than non-stereotypic animals. Masonet al emphasised reliable and valid welfare assessments require more than justdata on abnormal repetitive behaviour. Potential measures of stress andwelfare, also assessing how much animal’s value enrichment, can also be used. (Mason et al.
, 2007) A variety of environmentalenrichments is used to create outcomes that match an animals individual andspecies history. The techniques used aim to stimulate the animal’s senses tomimic their usage in the wild. Enrichment can be seen as auditory, olfactory, habitationalfactors and food. (Smithsonian’s NationalZoo). Environmental enrichment can be offered to captive animals in a rangeof locations including zoos and sanctuaries. It can be beneficial to a widerange of animals e.g.
land mammals, marine mammals and amphibians. (Ammpa.org).The Association of Zoos andAquariums (AZA) requires that husbandry and welfare is a main concern for animalsin captivity. AZA promotes the overall wellbeing of animals encompassing the mental,physical, social and biological characteristics. (Aza, 2013). GeneralApproachesAn animal’s interest that isevoked by any stimulus is considered enriching, this includes both natural andartificial objects, scents and novel foods. (Smithsonian’sNational Zoo).
Most enrichment stimuli canbe divided into seven groups:Environmental:Changes which add complexity to the captive animal’s environment. Feeding: To present food to an animal in different ways.E.g. hidden, scattered, buried, presented differently and food that ismanipulated. Manipulation: Items that can be manipulated by paws, feet, tail,head, mouth etc.
The aim is to promote investigatory behaviour and exploratoryplay that is closely related to behaviours that are seen in the wild. Pig producers are required toprovide enrichment for pigs to enable proper investigation and manipulationactivities. Scott et al showed singleor multiple hanging toys were able to show a comparable level of occupation tothat of the straw bedding. Toy manipulation only represented 5% of theremaining time. Manipulation of a single toy did not differ between the housingsystems.
Scott et al resultssuggested behaviour was more focused on enrichment toys. The type of feedingmay influence levels of enrichment manipulation. A pig playing with enrichmentmay cause that object to become more interesting to the other pigs. Levels oftoy manipulation were low in the study, possibly to the extent that there wasno social competition. This suggested that one toy would cater for all pigs.
The lack of skin lesions scores indicated a lack of aggressive behaviour. (Scott et al., 2007)Puzzles: Given to animals as simple problems that containfood. Sensory: Animal senses are stimulated e.g. visual,olfactory, auditory, tactile, and taste. (Smithsonian’sNational Zoo)Assessment of Environmental Enrichment A wide range of methods can beused to assess the most appropriate environment enrichments to be used.
Theseare used on the premise that captive animals should perform behaviours that aresimilar to their ancestral species. (Dawkins, 1989). One method is preference test studies, which leaves theanimal free to choose which activity or interaction they most prefer. (Sherwin and Glen, 2003).
Another methodis motivation studies, which assesses the impact of environmental enrichment onan animal’s motivation. (Sherwin andGlen, 2003). The assessment can include some or all the general approacheslisted above. Laboratorymice were offered a choice between white, black, green and red cages. Most ofthe mice preferred white cages, then black or green, red was the leastpreferred cage.
Familiar environment can influence preference choice. Sherwin and Glen showed 17 of the 24mice chose cages different to their home cage showing familiarity has littlepreference. Not much is known about how mice visually perceive theirenvironment. It remains uncertain what influences cage preferences in mice.Food consumption and body weight were inversely related. E.
g. the heaviestmouse ate less food. Sherwin and Glen speculatedcage colour effect on these characteristics could relate to home cage activity.Mice from the white home cages had the highest food consumption and the lowestbody weight. Home cage colour influenced mice behaviour in the raised plusmaze. Mice in red cages spent more time in the closed arms than white home cagecolour. The maze is established to test behaviour and used to indicate fear oranxiety. Greater use of closed arms in the maze indicates a more anxious orfearful animal.
Characteristics of home cage rodents influenced the responsesof laboratory rodents in behavioural tests of emotionality. Red cages wereleast preferred and the mice showed the greatest amount of anxiety. White cagesmay have lowered or did not change the level of anxiety, whereas red cages mayhave increased the levels of anxiety. (Sherwinand Glen, 2003). Foodbased enrichment can beas simple as leavingfood whole or for those animals able to climb throwing it on the roof ofthe enclosure or a raised platform. It can also bescattered, hidden or concealed in paper sacks.
Themost common sensory enrichment is olfactory. Using items such as herbs, spices,perfume, deodorant, catnip and toothpaste. Cognitiveenrichment uses objects such as Boomer Balls, Kong toys, tyres, cardboard tubesand fireman’s hoses to occupy the animals time. Mirrorscan be used as a form of social enrichment to effect mating and natural behaviours. Changesto the physical habitat include hiding food, adding enrichment objects toencourage natural behaviour and enhance their space to provide mentalstimulation. (Colchester Zoo). Enrichment Articles Useof Collard Green Stalks as Environmental Enrichment for Cockatiels Kept inCaptivity. They found the stalks increased food intake and reducedsleep activities.
There was no effect on body surface temperature, locomotion,maintenance and other resting activities. Green stalks proved they can be usedas enrichment, but did not significantly alter their overall behaviour. Lowersleeping activities were observed in the group with the green stalks (theenriched group). The result indicated that enrichment could be a promisingstrategy to reduce the fear response in captive parrots and similar birds. (Carvalho et al, 2017).Influenceof Environmental Enrichment on the Behaviour Performance and Meat Quality ofDomestic Pigs. They found that pigs with an enriched environment showedmore exploratory behaviour spending more than a quarter of their timeexhibiting that characteristic. In a barren environment pigs showed more timeexploring the fixtures of the pen than the other pigs.
They also were involvedin more harmful behaviour e.g. nosing other pigs, biting other pigs andaggressive head thrusting. Environmental enrichment improves the welfare ofpigs by reducing anti-social behaviour and an additional benefit of improvingmeat quality.
(Beattie, O’Connell andMoss, 2000).These two papers confirm that environmentalenrichment is beneficial but there are other papers that have also researchedenrichment in animals and have stated otherwise. In the case of the Cockatielsthe objective of the enrichment was to improve the behaviour and reduce thefear response which leads to undesirable behaviour. This statement also relatesto Sherwin and Glen, 2003, theylooked into the fear and anxiety of mice in coloured cages and in the raisedplus maze. However the study of the pigsdiffered in that there was a commercial driver to the enrichment and whilstthey also exhibited better behaviour the commercial spin off was better meatquality. Articlesabout Laboratory Fish Laboratory fish are very useful for a varietyof experiments.
MammalianImmunoassays for Predicting the Toxicity of Malathion in a Laboratory FishModel. Theuse of non-rodent species has increased for immunotoxicological evaluation ofchemicals. Fish are phylogenetically distant from humans.
Fish contain a numberof structural, functional and biochemical characteristics. Fish offeradvantages over the immunotoxicological mammalian models. Beaman et al, investigated the utility of NTP – validated mammalianimmune assays. The results will help to explain a specific panel of immuneassays.
The significant finding was sub chronic exposure of medaka to sublethal concentrations of Malathion which had little effect on immune functions.Malathion showed to produce neurotoxicity in fish similar in mammals. PFC(Plaque-forming Cell) response requires a concentrated effort which isdifficult in medaka and requires further study. Beaman et al, results demonstrated sub chronic exposure tonon-lethal concentrations of Malathion increased host susceptibility. When PFCwas suppressed host resistance was compromised. Beamanet al, also showed mammalian immune assays can be used successfully in fishto show toxicological hazards.
(Beaman etal., 1999)Fertile anddiploid nuclear transplants derived from embryonic cells of a small laboratoryfish, medaka. Wakamatsu et al transplanted embryonic cell nuclei in to unfertilizedeggs of medaka. Six transplants grew into adults, they were fertile andhomozygous and introduced marker genes. Genetic markers were passed down thegenerations in a Mendelian fashion. Wakamatsuet al demonstrated successful nuclear transplantation in fish. The first experimentwas the GFP gene was driven by a promoter gene (medaka EF-1a-A). The resultsindicated the transgene from the donor was expressed with characteristics ofthe promoter.
The second experiment consisted of the GFP transgene expressed inthe same pattern as the donor transgenic fish. Wakamatsu et al demonstrated nuclei of medaka blastula cells aretotipotent. The survival rate of nuclear transplants after the blastula stagewas lower in the first experiment when compared to the second one. In the firstexperiment PGM allozyme markers in the eggs was not detected. The geneticmarkers of the recipient fish were not obtained in the first or secondexperiment. (Wakamatsu et al., 2001) Articlesabout Enrichment in Fish EnvironmentalChange Enhances Cognitive Abilities in Fish.
They foundvariations in food rations for Cichlid fish (Simochromis pleurosphilus) in early life outperformed fish that hadconstant rations. This suggested environmental enrichment changes in early lifetrigger a better cognitive performance. The fish were tested one year later andthe difference in their cognitive ability stayed the same. Kotrschal and Taborsky suggested a single change can improvecognitive abilities for maybe a lifetime. Food rations were different forjuveniles as they were a range of sizes. Fish given less food showed moremotivation to eat the food.
When in adult hood, the fish sizes were all thesame, so motivation had been lost. (Kotrschaland Taborsky, 2010) EnvironmentalEnrichment Promotes Neural Plasticity and Cognitive Ability in Fish. They found thatjuvenile salmon that experienced an enriched environment for 8 weeks hadincreased ability to compensate for injury and adjust their activities inresponse to new situations (neural plasticity). The enriched fish were given amaze and made fewer mistakes.
Salvanes etal concluded that salmon exposed to an enriched environment during arearing period had a positive effect on cognitive learning. The salmon raisedin the non-enriched environment exhibited a disadvantage in cognitive learning.Enrichment, with regard to salmon has been found to have a positive on neuralplasticity and spatial learning.
(Salvaneset al, 2013). Both agree enrichment can have a positive effecton fish. Environmental enrichment can help fish in a manner of learning. Thetwo articles illustrate that when fish are placed in an enriched environmentearly in their life the result is positive changes in their behaviour andcognitive ability.Exploratorybehaviour in laboratory zebrafish: potential benefits of exploring the unknown.Quality oflife led by animals is influenced by cognitive stimulation.
Explorationopportunities in captive enrichment programs proved beneficial for improving welfare.Cognitive enrichment cannot exceed the skills and resources of the animal inorder for it to be effective. In Graham’sstudy zebrafish were quick to swim into the newly released area and thisinterest continued over the days observed. Fish did not express anxiousbehaviour, but did engage in affiliative behaviour. The evidence suggestedexploration behaviour may induce a positive emotional state. Zebrafish areknown to show anxiety, a measure of this is spatial location in the tank. Graham first studied zebrafish behaviourin tanks.
The fish were provided access to an unexplored area. The findings ofthis study show the fish did not show any anxiety. The fish stayed closertogether when more space was added to the tank. Graham’s finding of increased cohesion and co-ordination in theabsence of threat showed distress may not be an only driver of the group.Normally laboratory housing for zebrafish consist of small or barren tanks.
Animals in the wild have the opportunity to explore their environment freely.Laboratory environments have resulted in abnormalities in behaviour. Thefindings from this study suggests social behaviour of zebrafish is affected bypositive situations.
Graham’s findingssuggested a more natural environment is important for animal welfare and so isthe opportunity to explore. (Graham, 2017) Sleepbehaviour in all species articles Do allanimals sleep? One assumption made is all animals or those with a nervous system sleep.Another assumption is sleep deprivation is very harmful. The assumptionscombined suggest sleep is a vital function. Most animals adjust their activityto the conditions they inhabit. Reduced alertness and activity in animalscannot be associated with sleep.
Sleep in animals is when circadian rhythmshave been eliminated. It is important to not mix sleep with rest. Sleep can bedefined as a reversible state of immobility and reduced sensory responsiveness.Two types of sleep have been found in mammals, non-REM sleep and REM sleep. Non-REMsleep is reduced activity in brainstem systems, whereas REM sleep is a patternof discharge that resembles a ‘waking’ in most brain regions.
To Siegel’sknowledge there hasn’t yet been any claim of sleep in unicellular organisms.Rest deprivations in cockroaches did not produce a consistent increase in resttime during a recovery period. Drosophilahave been found to show a behavioural state which meets the criteria ofsleep.
In studies of sleep behaviour in zebrafish, circadian variations inactivity and responsiveness increased and a decrease in response to stimuli wasseen after rest deprivation. Activation of the perch by light during theirinactive periods resulted in an increase of rest behaviour during the subsequent12 hour period. In a study of activity and responsiveness in the bullfrog this showedlevels of activity varied in a circadian pattern. The bullfrog was more alertduring periods of inactivity when compared to periods of activity.
In a studyof the tree frog it was concluded this species slept. In the turtle, quiescentbehaviour increased after disruption of quiescent states. Birds have been foundto show REM and non-REM sleep. Sleep has been studied in a few mammaliandomesticated species, these species met the general definition of sleep.
Usingonly behavioural responses Siegel cannotsafely say herbivores meet the criteria for sleep. Sleep in the fur seal onland can resemble terrestrial mammals. In dolphins and cetaceans is quitedifferent, they only show uni-hemispheric slow waves.
In smaller cetaceans,motor activity in continuous from birth to death. (Siegel, 2008)Cluesto the function of mammalian sleep. Sleep can be defined as a state of immobilitywith reduced responsiveness.
The changes in brain metabolism and neuronalactivity during sleep increases when compared to most waking periods. In thisarticle Siegel considered theknowledge that has been gained about sleep and sleep – control mechanisms.Neurophysiological studies have provided a lot information about the mechanismscontrolling sleep.
Non-REM sleep can be started by the isolated forebrain. REMsleep can be started by the isolated brainstem. Changes in localisedtemperature in the brainstem and forebrain cannot be confused withenvironmental temperature. Recent studies suggest that the cessation ofhistamine neuron activity can be linked to the loss of consciousness in sleep.To study theories of REM and non-REM sleep function, you have to consider howsleep amounts differ across species. A species diet can be correlated withsleep time. Another aspect of sleep is linked to body mass and brain size.Studies on mammalian sleep have been mainly researched on placental ormarsupial mammals.
Terrestrial mammals show relatively high – voltageneocortical EEG activity during non-REM sleep. Slow wave and spindle waves arenot enough as evidence of sleep. Studies of arousal has not been performed on cetaceansacross putative sleep – wake cycles. Terrestrial mammals have minimal activityand maximum sleep. Siegel hypothesisedthat the continuous activity of cetaceans has adaptive value. Fur seals exhibitdifferences in sleep when compared to terrestrial mammals.
There are lots oftheories to explain the functions of REM and non-REM sleep. A common theme intheories is sleep time, it is determined by neuronal activity in the neocortex.Neocortical size does not seem to be a determinant of non-REM or REM sleepamounts. Sleep restriction leads to feelings of sleepiness. Skin lesions,hyperthermia followed by hypothermia, increased food intake and death are signsof long – term sleep deprivation.
Sleep may be adaptive as it conserves andsuppresses energy across a 24 hour day. Energy conservation can be important innewborns. Sleep may be able to defend against stress in herbivores. Sleep canhave multiple functions for the brain and body. (Siegel, 2005) Sleepbehaviour in fish articles AdultZebrafish as a Model Organism for Behavioural Genetics. Sleep behaviourand physiological function is not fully understood but is a widespreadphenomenon. At night zebrafish have periods of two to four minutes ofinactivity, floating horizontally whilst making small pectoral fin movements.
Zebrafish have also been found to have a reduction of facial movements whichsuggests lower respiratory levels. Any disruption e.g.
light, vibration,electric shock or forced movement, in sleep behaviour increases sleepdeprivation. Zebrafish also show daily rhythmic cycles that can be influencedby the environment (circadian rhythmicity). (Nortonand Bally-Cuif, 2010)Characterisationof Sleep in Zebrafish and Insomnia in Hypocretin Receptor Mutants. The researchcentered on the increased arousal threshold for zebrafish and the degree towhich this was reversible by gentle tapping, acoustic stimulation or weakelectrical field.
Fish in the active state were more likely to respond to lowervoltage stimuli however at higher voltages all fish responded irrespective oftheir state. With regard to tapping or acoustic stimuli rapid habituation wasnoticed and therefore in an effort to create sleep deprivation the electricalstimuli was retained as habituation was less of a problem. The end result wasthat sleep deprivation was achieved, and on releasing into a dark environmentthis resulted in modest sleep recovery in those that were partially deprivedand significant recovery in those that were fully sleep deprived.
However whenthe sleep deprived fish were released into light there was no sleep rebound. (Yokogawa et al., 2007) Howit all links together Environmental enrichment is beneficial for wildand domestic species. A variety of enrichment techniques can be used togenerate a number of beneficial outcomes. There is a range of drivers thatrequire the use of enrichment, whether they are commercial for domesticlivestock or helping different species cope with captivity. With particularregard to fish, the range of enrichment alternatives is narrower than thatavailable for mammals and birds.
Enrichment with regard to fish is largelyrestricted to availability of food as highlighted in Kotrschal and Taborsky and Salvanes, et al. Further researchconducted by Yokogawa, et al exploredin detail the effect on sleep deprivation on zebrafish with particularreference to the types and strengths of stimuli to arouse the fish from thesleep-like state. The research was further expanded to examine the homeostaticresponse when sleep deprived fish were released into either a light or darkenvironment. In this study fish,sleep and enrichment will be combined together.
Aims The aim for this project is tosee if enrichment given to fish during the day effects the sleep behaviour offish during the night.