Uticaj smeštaja na telesnu masu, masu unutrašnjih organa i agresivno ponašanje mužjaka miševa soja Swiss

Abstract

Laboratorijski miš je najĉešće korišćena ţivotinja za nauĉne i druge svrhe u biomedicinskim naukama. Jedan od problema koji se javlja u njihovom gajenju i korišćenju u ogledima tiĉe se pojave agresivnog ponašanja muţjaka u procesu uspostavljanja hijerarhijskih odnosa. Agresivnosti meĊu muţjacima miševa sa posledicama ranjavanja, trpljenja bolova, podvrgavanja stresu i uginuća, svakako nepovoljno deluju na njihovu dobrobit i validnost rezultata istraţivanja. Ovi problemi u grupnom smeštaju danas se rešavaju obogaćenjem ţivotne sredine - dodavanjem razliĉitih predmeta i materijala u kaveze, koje miševi mogu da koriste za izgradnju gnezda i skrivanje, kao i usklaĊivanjem broja muţjaka u grupi i optimalne veliĉine kaveza, odnosno optimizacijom gustine naseljenosti. MeĊu istraţivaĉima i struĉnjacima o navedenim pitanjima i ponuĊenim rešenjima obogaćivanja postoje opreĉna mišljenja. U vezi obogaćenja kaveza kod muţjaka miševa pojedini autori tvrde da ono remeti eksperimentalne procedure, validnost rezultata, kao i da pospešuje agresivnost meĊu muţjacima miševa u grupi, a drugi autori smatraju da se smanjuje agresivnost i njegove posledice a da obogaćenje uopšte ne utiĉe na ogledne rezultate. Imajući u vidu izneto, postavljeni su ciljevi istraţivanja u ovoj disertaciji koji su se sastojali u izuĉavanju uticaja smeštaja i obogaćenja kaveza na telesnu masu, masu unutrašnjih organa i pojavu agresivnog ponašanja muţjaka miševa soja Swiss (Mus musculus Linnaeus, 1758). Istraţivanja su sprovedena u Institutu za medicinska istraţivanja Vojnomedicinske akademije u Beogradu na muţjacima miševa soja Swiss iz sopstvenog uzgoja, a obuhvatala su period uzgoja muţjaka miševa od odbijanja od majki (u uzrastu od 21 dan) do polne zrelosti (u uzrastu od 56 dana). Miševi (ukupno 109 muţjaka) su podeljeni u 3 eksperimentalne grupe (A, B i C) na naĉin da grupa A ima ukupno 45 jedinki smeštenih u 15 kaveza po tri miša, grupa B ukupno 32 jedinke smeštene u 4 kaveza po 8 miševa i grupa C ukupno 32 jedinke smeštene u 4 kaveza po 8 miševa. U pogledu smeštaja muţjaci miševa su bili rasporeĊeni u standardnim kavezima (″Ehret tip II″, P=363cm2) sa prostirkom od drvene strugotine, hranom i vodom ″po volji″ bez obogaćivanja ţivotne sredine (grupa A), standardnim kavezima (″Ehret tip III″, P=825cm2), sa prostirkom od drvene strugotine, ishranom i napajanjem ″po volji″ bez obogaćivanja ţivotne sredine (grupa B) i standardnim kavezima (″Ehret tip III″, P=825cm2) sa prostirkom od drvene strugotine, hranom i vodom ″po volji″ sa obogaćenjem ţivotne sredine (materijal za gneţĊenje – papirna vata iseckana u niti i tri predmeta - posuda od polipropilenske plastike sa otvorima sa strane i na gornjoj površini, ĉaša od polipropilenske plastike i cevi kvadratnog oblika od polipropilenske plastike sa otvorima na oba kraja)...

The laboratory mice are the most commonly used animals for experiments for scientific and other purposes in biomedical sciences. One problem that occurs in their growth and utilization in experiments concerns the appearance of aggressive behaviour of males in establishing a hierarchy. Aggression among male mice lead to wounds, pain, being stress and mortality - definitely negative effects on their welfare and validity of research results. The problems in group accommodations today are solved enrichment of the environment - by adding different items and materials in cages that mice can be used to build nests and hiding, as well as adjusting the number of males in the group and the optimal size of the cage, and optimizing population density. Regarding these issues and enrichment possible solutions, conflicting opinions among researchers and experts are present. Regarding the cage enrichment of male mice, some authors argue that it violates the experimental procedure, the validity of the results, as well as promotes aggression among male mice in the group, while the others believe that it reduces aggression and its consequences and that enrichment does not affect the sample results. Having in mind the above presented, the goals of the research of this thesis were set, through studying the influence of housing and enrichment of cage on body weight, weight of internal organs and the emergence of aggressive behaviour of male mice of the Swiss (Mus musculus Linnaeus, 1758). The study was conducted at the Military Medical Academy Institute for Medical Research in Belgrade on male mice of Swiss breed from their own farm, covering the period from weaning male mice (aged 21 days) until full maturity (age 56 days). The total of 109 male mice were divided in three experimental groups (A, B and C). In the group A were 45 males accommodated in 15 cages (three mice each), while in groups B and C were 32 males divided in 4 cages (8 mice each). The mice of the group A were reared in standardized cages (″Ehret type II″ of 363cm2) with wooden sawdust bedding, feed and water ad libitum without environmental enrichment. In the other two groups, male mice were reared in standardized cages (″Ehret tip III″ of 825cm2), with wooden sawdust bedding, feed and water ad libitum without environmental enrichment in the group B and with environmental enrichment in group C, consisting of paper wadding cut into a fibres as nesting material - and three objects: a polypropylene plastic cup and polypropylene tubes with openings at both ends.