Biomedical subjects

B Savenije

Publications and source records attributed to B Savenije.

4 recordsLinked to original sources

PubMed2000

Electrical stunning and exsanguination decrease the extracellular volume in the broiler brain as studied with brain impendance recordings.

Electrical stunning in the process of slaughtering poultry is used to induce unconsciousness and immobilize the animal for easier processing. Unconsciousness is a function of brain damage. Brain damage has been studied with brain impedance recordings under ischemic conditions. This experiment studies brain impedance as a response to a general epileptiform insult caused by electrical stunning and ischemia caused by exsanguination. Brain impedance was recorded in 10 broiler chickens for each of three killing methods: whole body electrical stunning, which induces cardiac arrest; head only electrical stunning followed by exsanguination; and exsanguination without stunning. Brain impedance was converted into relative extracellular volume (ECV) values. Results showed that, immediately after electrical stunning, the ECV decreased 5.5% from base ECV. With exsanguination only, the ECV decreased from base ECV only after 4 min after neck cutting. The ECV decrease after 10 min did not differ between treatments. With a time of 228 s to reach one-half of the ECV decrease found at 10 min, electrical stunning resulted in a much faster change in ECV than exsanguination only (373 s). Within the head only stunning group, six animals showed a response similar to that found with whole body stunning; the other four animals responded similarly to the animals that were exsanguinated only. It was concluded that brain impedance recordings used with electrical stunning reflect brain damage. This damage was both epileptic and ischemic in nature. Whole body stunning induced immediate brain damage, suggesting that an adequate stun was delivered. The dual response found with head only stunning might indicate that this stunning method does not always produce an adequate stun.

Abattoirs↗

PubMed1998

Impedance recordings to determine change in extracellular volume in the brain following cardiac arrest in broiler chickens.

The present study describes a method to determine the onset and development of brain damage in broiler chickens. Exsanguination disrupts the brain metabolism and causes the brain to become ischemic. Energy-requiring systems in the cell membrane fail, which results in an ionic shift over the membrane, accompanied by a water influx into the cell. This cellular edema decreases the extracellular volume of brain tissue. In mammals, this brain damage has been measured by recording brain impedance. We adapted this approach for use with poultry. Five to six-week-old commercial broilers were equipped with impedance recording electrodes in the striatum area of the brain. Cardiac arrest was induced by means of an intravenous injection of MgCl2 and brain impedance was recorded for 30 min. The resulting curves showed a high similarity to those obtained in rats. No effects of 12 h antemortem feed deprivation on the size and rate of change in brain impedance could be found. Both in anesthetized and conscious birds, a change in brain impedance was found. We conclude that brain impedance can be used to determine the development of ischemic brain damage in broiler chickens.

Animals↗

PubMed1997

The effects of mixing on behavior and circadian parameters of salivary cortisol in pigs.

The present study describes an experiment that was carried out to study the effects of mixing pigs once at 25 kg, preceded by transportation for 1.5 h, on the behavior and the circadian rhythmicity of salivary cortisol. The frequency of agonistic interactions was higher for mixed pigs. This was not only the case immediately after mixing, when pigs started to fight to establish a new social rank (p < 0.05), but also 5 to 6 weeks later; still more headknocks and bites towards other pigs were seen at that time among mixed pigs (p < 0.01). However, neither the basal cortisol concentration, assessed as the MESOR of the circadian rhythm of salivary cortisol, nor the amplitude of that rhythm was different between the groups.

Aggression↗

PubMed1996

Health, welfare, and productivity of pigs housed under Specific-Stress-Free conditions in comparison with two-site systems.

This study describes the effects of housing pigs under optimal climatic conditions in a Specific-Stress-Free (SSF) housing system on health, behavior, immunological responsiveness, and production performance of 78 pigs from 10 litters. Pigs housed in an SSF system, where they were neither mixed nor transported, were compared with a control group of pigs for which transport was simulated and which were mixed at approximately 25 kg; transportation to another location and mixing are usual procedures in two-site systems. The SSF pigs had a higher growth rate for the finishing period (P < .01), but this was a smaller improvement in performance than in previous studies, probably due to less mixing in this study. Clinical signs were hardly seen in the SSF group, but aggression after mixing caused ear lesions in the control group. Pigs that were not mixed had a higher response 12 and 18 h after an intradermal injection of phytohemagglutinin (P < .001) compared to the control pigs. At 1 d ad 1 mo after mixing the control pigs, more agonistic interactions were seen in these pigs compared with the SSF pigs (P < .05 and P < .01, respectively). In conclusion, health, welfare, and production performance of pigs are improved when pigs are kept in an SSF housing system where they are not mixed or transported.

Animal Welfare↗