The Effect ofthe Slaughter Method, Inbred, Age and Race on the Glutathione Level in some Organs of Rabbits (short communication)

Zusammenfassung Titel der Arbeit: Einfluss von Schlachtmethoden, Inzucht, Alter und Rasse auf die Glutathionkonzentration in Leber, Niere und Muskel bei Kaninchen (Kurzmitteilung) Es wurden 180 Kaninchen der Weißen Neuseeländischen (NZB) und Bay Black Rasse (BBB) im Alter von 70 und 140 Tagen hinsichtlich der Glutathionkonzentration (GSH) in einzelnen Organen untersucht. Die jüngeren Tiere erreichten in Leber, Niere und Muskel höhere GSH Werte als die älteren Tiere. Die NZB wiesen eine höhere NZB auf als die Tiere der BBB. Bei Inzuchttieren beider Rassen wurde eine höhere GSH nachgewiesen. Eine 10 %ige MgS04 Injektion vor der Schlachtung bewirkte eine Erhöhung des Glutathionniveaus in den untersuchten Organen.


Introduction
Glutathione /GSH/ has an essential influence on the direcüons and intensity of some metabolic processes (ASSMANN et al., 1998;BRAY and TAYLOR, 1993;FOX et al., 1996;SEN, 1997;SMITH et al., 1996;SUZUKI et al., 1998 ).As the role of GSH in organism is significant, the aim of this study was to determine its content in organs of the model animals, such as rabbits, depending on breed, age.mating as well as the slaughter method.

Material and Methods
The study was performed on 120 rabbits of the New Zealand White breed.The animals were 70 day old and 140 day old, weighed 0.8-1.2kg and 2-2.0 kg suitable, mated inbred (the parents : brother x sister, father x daughter, mother x son) and random, and 60 rabbits of Black Bay breed, aged 140 days, weighed 2.0-2.5 kg also mated randomly and by inbreding.The animals were kept in Standard cages in ventiled farm room of temperature 18°C and 50:50 dark/light in the Department of Genetics and Methods of Animal Improvement ofthe Academy of Agriculture in Cracow.
The animals were fed Standard industrial granulated fodder for rabbits, a diet consisting of 15 % protein and hay ad libitum aecording to farm System of feeding.They had the access to water too.The all individuals had the good veterinary nurse.The animals of first subgroup were killed by breaking their spinal cord with strong blow (classical method) while in the second subgroup by injection of 2 ml/kg b.w. 10 % Solution of MgS0 4 to the ear vein.After the administration of MgS0 4 or the blow the animals were allowed to bleed.The control subgroups were the rabbits slaughtered by the "classical method".After slaughter, always in the time 10 00 -12 00 a.m.tissue slices of liver, kidney and muscle /musculus longissimus dorsi at the height of the last rib/ were homogenized in a glass Potter homogenizer cooled to 4°C in 10 ml of 0.25 M Sacharose containing 10 mM EDTA.Homogenates were centrifuged for 15 minutes in a Janetzki K-24 centrifuge under 12 000 g./min.After deproteinization by 10% trichloroacetic acid in supematant the level of glutathione by the ELLMAN method (1959) was determined.The Substrates were produced by Serva Company.Extinction values were recorded on a Specol photometer at the wavelenght 412 nm.The results obtained were calculated statistically aecording to the test-Student.

Results
Table 1 shows that 70 day old animals ofthe New Zealand group had a statistically I-I...5-5 Ihe slalislically confirmed differences between the groups of rabbils killed classicaly and MgSO, adminislralio higher level of GSH than 140 day old ones.GSH level in the liver, kidney and muscle was somewhat higher in the random than in the inbred animals.The GSH level was statistically higher in the liver than kidney and muscle and higher in the kidney than in the muscle.Table 2 and 3 inform that of the GSH level in all of studied organs was higher after magnesium sulfate administration.Besides, NZ animals had in all organs the hieher GSH concentration than BB rabbits.

Discussion
The results obtained revealed in the majority of cases the significant changes of GSH concentrations under the influence of the slaughter method, the kind of mating, age and breed.These phenomena can suggest the existence of a differentiated metabolism rate in the studied organs depending on age, breed, the degree of relationship.It may be determined by adaptation possibilities too, because the organs studied are functionally different (JOCELYN, 1972;SWIDERSKA-KOLACZ and KOLATAJ 1994).In the animal cells the glutathione level seems to be dependent of aee (LENARTOWICZ et al., 1996).g It is known, younger animals have a higher metabolism rate, and the glutathione is amongst others, connected with their higher red-ox potential in the cells (BRAY and TAYLOR, 1993;BROWN,, 1994;FOX et al., 1996).Our experiment would conf.rmthis Suggestion because the 70 day old rabbits had a higher level of thiol groups than 140 day old ones.The earlier studies of KOLATAJ et al. (1979) revealed that in the content of sulfhydryl Compounds in the blood and some organs of hens and chickens were inter-breed differences.New Zealand rabbits from our experiment had a higher level of glutathione than the animals ofthe Bay Black breed.In all the studied organs of inbred rabbits was the level of thiol groups lower than in the randomized animals.It is known that the homozygosity in animals is not favourable.It may be due amongs others, that lower glutathione level in the inbred rabbits may be interpreted in the connection with the inbred relationship.An analysis of stress caused by "classical" slaughter and narcosis by 10% Solution of MgS0 4 revealed a higher level of glutathione after MgS0 4 injection.Probably it is the result antistress action of Mg 2+ ions (EVANS et al., 1996;LEHR, 1981;SEELIG, 1980;).The role of Mg 2+ in defensive processes as an antistress and antitoxic factor was discussed by DURLACH (1991).It has been found that Mg 2+ has an effect on the release of neurotransmitters, counteracting the effect. of calcium.Mg + ions weaken probably stress reaction by participation in intracellular degradation of catecholamines too.Application of MgS0 4 as a slaughter medium has proved that it is more favourable than the classical method of hitting the neck by a bar.In the case of slaughter by narcosis the animal is only subjected to injection MgS0 4 to the ear vein conducted in a possibly mild and stress-free way.During "classical" slaughter the animal is turned down by the head, suspended in the air.It receives a blow in the neck and it is subjected to a strong stress action from the side of central nervous system and peripheral Stressors.Besides, after the blow occur preagonal tetanic convulsions, prolonged muscle contractions which are not favourable for the subsequent consume quality of meat because they change the picture of muscle glycolyse processes.In connection with these suggestions we would like to propose the MgS0 4 administration in the conditions of slaughter without the stress.Dieses interessante, breitgefächerte und lesenswerte Buch enthält wichtige Basis-und Hintergrundinformationen für eine wissenschaftlich begründete Wild-und Waldbewirtschaftung sowie eine waidgerechte Jagd ebenso, wie aktuelle Informationen über den Schutz und den Nutzen von Wildressourcen.Neben Biologen, Ökologen, breiten Kreisen der Jägerschaft, Land-und Forstwirten, Tierärzten, land-und forstwirtschaftlich ausgerichteten Institutionen ist dieses Buch allen Naturfreunden zu empfehlen.
The level (x±S d ) of GSH in the liver, kidney and muscle (nM/g of tissue) of 70 day old New Zealand rabbits, mated inbred and random, killed clasically and by 10% MgSQ 4 injection; n in each subgroup=15 I-I...6-6 Ihe Statistical!)* confirmed differences betv/een 70 day old and 140 day old animals: 7-7,...18-18 the statistically confirmed differences between Organs;

Table 3
The level (x±S d ) of GSH in the liver, kidney and muscle (nM/G of tissue) of 140 day old mated inbred and oo It L »«f*'c"i.cauciweenme vamesjo.8-8....16-J6 Ihe stalisiically confirmed differences between the races.