Det er ikke ment som et angrep på Anettes måte å gjøre ting på (som sannsynligvis er helt lik mange andre oppdretteres måte å gjøre ting på), setningen satte meg bare på sporet av en problemstilling, og er tatt med for å vise det alle oppdrettere opplever - at rottemor reagerer på at ungene blir fjernet fra redet. Utvilsomt regaerer også ungene på dette, selv om oppdretteren ikke nødvendigvis oppfatter det.Anette wrote: Det er ikke alle billedene som er gode da moren blir litt stresset da når jeg tar alle sammen ut,
Det er gjort utrolig mye forskning på effektene av å separere rotte- og museunger fra mor i kortere og lengre perioder under de første 0-3 leveukene, både på unger og mors mentale og fysiske helse. Jeg kan liste en lang rekke artikler for de spesielt interesserte (har nemlig vært innom disse tankene noen ganger før), men nevner noen få her som grunnlag for videre diskusjon. Vet vi egentlig nok om hvor mye vi påvirker rottene ved å separere dem så tidlig? Hva er fordelene ved å gjøre det? Den mest åpenbare fordelen er å kunne følge med vektutviklingen, men hvor ofte er det nødvendig å veie hvis kullet ser ut til å utvikle seg normalt? Jeg vil gjerne ha innspill både fra oppdrettere og ikke-oppdrettere. Har dere andre artikler som kan diskuteres i denne sammenhengen er det også fint!
Referanser (til å starte med, i det minste):
Meaney MJ et al (1996) Early environmental regulation of forebrain glucocorticoid receptor gene expression: Implications for adrenocortical responses to stress. Developmental Neuroscience 18 (1-2), 49-72.
Utdrag: The adrenal glucocorticoids and catecholamines comprise a frontline of defense for mammalian species under conditions which threaten homeostasis (conditions commonly referred to as stress). The development of the hypothalamic-pituitary-adrenal (HPA) response to stressful stimuli is altered by early environmental events. Animals exposed to short periods of infantile stimulation or handling show decreased HPA responsivity to stress, whereas maternal separation, physical trauma and endotoxin administration enhance HPA responsivity to stress. In all cases, these effects persist throughout the life of the animal and are accompanied by increased hypothalamic levels of the mRNAs for corticotropin-releasing hormone and often arginine vasopressin. Thus, the early environment can contribute substantially to the development of stable individual differences in HPA responsivity to stressful stimuli.
Jaworski et al (2005) Effects of early maternal separation on ethanol intake, GABA receptors and metabolizing enzymes in adult rats. Psychopharmacology 181 (1), 8-15.
Utdrag: Rationale: Maternal separation (MS) in neonatal rats affects ethanol self-administration (SA) in adulthood. The goal of this study was to determine the effect of MS on ethanol SA in adulthood in different groups of rats, which control for time of separation, handling, and rearing conditions and, for mechanistic assessment, to examine GABA-A receptors in the central nucleus of the amygdala (CeA) and levels of liver metabolizing enzymes. Methods: Newborn, male Long-Evans rats were randomly assigned to different groups and treated over postnatal days 2-14. The rats were picked up by their tails and put back down with no separation (MS0), separated from their mother for 15 min/day (MS15), separated from their mother for 180 min/day (MS 180), handled once for a bedding change (NH), or were animal facility reared (AFR). In adulthood, these rats were allowed 5-day continuous access to ethanol, and GABA-A receptors and liver enzymes were measured. Results: The MS15 group consumed and preferred significantly less ethanol (about one third) than the MS180 group; however, neither group was different from the MS0 or the AFR group. The NH group consumed and preferred significantly more ethanol than all other groups, at least twice that of the MS180s. GABA-A receptors were increased in the CeA in MS15s, which could help explain the effects. Alcohol dehydrogenase may have been altered in the AFRs. Conclusions: Various treatments in neonates affect ethanol intake and GABA-A receptors, and possibly ethanol metabolism, in adulthood. These changes were not simply related to time of separation but were also due to the degree of handling.
Soriano O et al (2006) Contributions of undernutrition and handling to huddling development of rats. Physiology & Behavior 89 (4), 543-551.
Utdrag: When newborn rats are separated from the mother, they consistently exhibit the huddling response to maintain body temperature and physical contact. Initial and final temperatures in the pile of undernourished (U) and undernourished stimulated (Us) pups was reduced compared to their controls (C and Cs, respectively). Huddling latency was prolonged at 5 days of age in the Us group and at 20 days of age in the U pups. The data provide evidence that both neonatal undernutrition/maternal deprivation and early sensory stimulation may modify the huddling response by reducing or increasing, respectively, brain mechanisms underlying huddling. The amount of physical contact the newborns receive from their littermates and the mother may be a fundamental source of sensory cues for neuronal maturation and brain functioning.
Mazaro R, Lamano-Carvalho TL (2006) Prolonged deleterious effects of neonatal handling on reproductive parameters of pubertal male rats. Reproduction fertility and development 18 (4), 497-500.
Utdrag: The purpose of the present study was to investigate the long-lasting effects of neonatal handling on reproductive parameters of male rats. Neonatal handling (pups separated from their mothers, kept isolated at environmental temperature for 20 min and submitted to 1 min of tactile stimulation) was applied from post partum Days 1 to 14 (a stress-hyporesponsive period, SHRP). The association of the slightly aversive stimuli applied during the SHRP proved to have lasting deleterious effects on male reproduction, causing lower testicular weight and reduced values of seminiferous tubule diameter and germinal epithelium thickness at puberty, which resulted in a 25% reduction in the daily sperm production and in the number of mature spermatids. Similarly, the number of Sertoli cells per tubular cross section was 20% smaller and the weight and number of spermatozoa were reduced more than 40% in the cauda epididymidis of animals handled.
Pryce CR et al (2001a) Comparison of the effects of infant handling, isolation, and nonhandling on acoustic startle, prepulse inhibition, locomotion, and HPA activity in the adult rat. Behav Neurosci 115:71–83
Pryce CR et al (2001b) Comparison of the effects of early handling and early deprivation on maternal care in the rat. Dev Psychobiol 38(4):239–251.
Veenema AH et al (2006) Effects of early life stress on adult male aggression and hypothalamic vasopressin and serotonin.
EUROPEAN JOURNAL OF NEUROSCIENCE 24 (6): 1711-1720.
Moles A et al (2004) Postnatal stress in mice: Does "stressing" the mother have the same effect as "stressing" the pups? Developmental psychobiology 44 (4), 230-237.