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Effects of extruded or pelleted diet on blood glucose, body weight, feed and water consumption in rats
by by Christina Jacobson & Michael Maslov

Extruded diets are claimed to be more digestible, palatable and of a higher hygienic standard compared to pelleted diets. In a comparision of a pelleted and an extruded diet given to Sprague-Dawley rats, we found no difference in weight gain, feed and water consumption or in blood glucose level. In the microbiological analyses, there was no major difference either. When considering choice of diet the physical form seems to be of minor importance. The major factors should be the nutritional value, hygienic level (autoclavable or irradiated vs conventional), reproduciability, availability, confidence in producer and economical values.

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Cross-fostering in the rat performed shortly after delivery: description of the procedure
by Edel Holene, Patricia A. Engen and Kristin Wear Prestrud

This paper describes a cross-fostering procedure in rats performed shortly after delivery. The aim of the procedure was to create groups of offspring that were exposed to a lipophilic test chemical exclusively in utero or through lactation, in addition to a control group. Time-bred dams were watched during delivery and their litters were exchanged before the young started to suckle. All dams accepted their role as foster-mothers. We had no previous experience in performing this kind of study. The following precautions taken have probably contributed to make a successful cross-fostering: It was restricted access to the animal facilities during the gestation and lactation periods and only a limited number of persons performed the experimental procedure. The dams became used to handling during the gestation period. Dams were temporarily removed from their litter and cages about three hours after delivery and just before they started to nurse the young. The new-born pups were kept warm and cleaned during the switch of cages. Dams were returned to their home cages containing foster-pups. It was a minimum of physical disturbances during the delivery and the person who performed the cross-fostering was familiar to the animals through previous handling. Twenty-nine litters were successfully cross-fostered.

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Reduction of atmospheric ammonia (NH3) and incidence of pulmonary lesions in mice kept in plenum chamber microenvironmental ventilation system
by by Maria Araújo Teixeira, Paulo Hilário do Nascimento Saldiva, Nívea Lopes de Souza, Idércio Luiz Sinhorini & José Luiz Bernardino Merusse

In the plenum chamber microenvironmental ventilation system (MEV) for laboratory animal housing, air exchanges are made directly inside animal cages. In this study we measured the daily levels of ammonia (NH3) in cages without bedding changes and made comparative histopathological analyses of mice born and kept in two different systems. Mice were kept under the MEV (n=40, in five cages) and general diluting ventilation (GDV) (n=32, in four cages) systems for nine days. In the MEV system, NH3 was not detected in the first three days. The highest concentration occurred on the seventh day (5.00+/- 2.90ppm). On the ninth day, a level of 2.50+/-1.70 ppm was measured. In GDV, NH3 was detected from the first day, and the highest levels were observed on the third and fifth day (31.20+/-12.50 ppm), respectively. From the fourth to the ninth day, the GDV system presented higher concentrations of NH3 than the MEV system (p<0.05). Histopathological analyses of lungs of six female mice from each group were performed after keeping mice in the two systems for 56 days. In the score evaluation, the incidence of chronic focal pneumonia, catarrhal bronchitis, and interstitial pneumonia was significantly higher (p<0.05) in the GDV group. Using morphometry, it was observed that animals from the GDV system showed a significant increase (p<0.05) in the volume fractions of the epithelium, when compared to the MEV system (24.50+/-5.60 m3/m2 and 19.70+/-4.90 m3/m2, respectively). An estimator of the numerical density of nuclei over 100 m of basement membrane was significantly higher (p<0.05) in animals from the GDV system, when compared to animals from the MEV system (14.60+/-3.00 and 10.84+/-3.00, respectively). It was shown that animals kept in the MEV system presented better health condition than animals kept in the GDV system.

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Baltic Laboratory Animal Science Association

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Baltic Journal of Laboratory Animal Science

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Protokoll
Sammanträdesdatum 2001-05-15

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Årets "Lars Wass-stipendiat" utsedd

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International Travel Fellowship - AALAS 2001

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Scand-LAS Symposiestipendier / Scholarships

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Mark of honour

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Meetings