Biomedical subjects

B Savenije

Publications and source records attributed to B Savenije.

7 recordsLinked to original sources

PubMed2002

Effects of feed deprivation and electrical, gas, and captive needle stunning on early postmortem muscle metabolism and subsequent meat quality.

The general method for stunning poultry before slaughter is by immersion of a chicken's head into an electrified waterbath. This method results in carcass and meat quality deficiencies. The major problems are hemorrhages and a delay in onset of rigor mortis, which increases the risk of cold shortening with early deboning. In two experiments, this study examines the early postmortem metabolism in the breast muscle and its effect on ultimate meat quality. The first experiment describes the effects of 5 h feed deprivation on the availability of glycogen from the liver and the breast muscle, of waterbath and head-only electrical stunning on pH and metabolite levels up to 6 h in unprocessed muscle, and the consequences on meat quality. The second experiment compares the same measurements after waterbath and head-only electrical stunning, CO2/O2/N2 and Ar/CO2 gases, and captive needle stunning. Metabolic degradation halted after 6 h without processing or after 4 h under conventional conditions after waterbath and CO2/O2/N2 stunning. With other stunning methods, this occurrence is at a faster rate, largely depending on muscle activity. Muscle glycogen does not need to be exhausted for energy generation to cease. If glycogen is a limiting factor, as found with head-only stunning, pH drops too rapidly and affects water-holding capacity and color. Hemorrhage scores were higher with electrical stunning than with other stunning methods. Gas stunning affected color and, to a lesser extent, water-holding capacity. Captive needle stunning scored between gas and electrical stunning on most measurements.

Abattoirs↗

PubMed2002

Development of brain damage as measured by brain impedance recordings, and changes in heart rate, and blood pressure induced by different stunning and killing methods.

Poultry are electrically stunned before slaughter to induce unconsciousness and to immobilize the chickens for easier killing. From a welfare point of view, electrical stunning should induce immediate and lasting unconsciousness in the chicken. As an alternative to electroencephalography, which measures brain electrical activity, this study used brain impedance recordings, which measure brain metabolic activity, to determine the onset and development of brain damage. Fifty-six chickens were surgically equipped with brain electrodes and a canula in the wing artery and were subjected to one of seven stunning and killing methods: whole body electrical stunning; head-only electrical stunning at 50, 100 or 150 V; or an i.v. injection with MgCl2. After 30 s, the chickens were exsanguinated. Brain impedance and blood pressure were measured. Extracellular volume was determined from the brain impedance data and heart rate from the blood pressure data. An immediate and progressive reduction in extracellular volume in all chickens was found only with whole body stunning at 150 V. This treatment also caused cardiac fibrillation or arrest in all chickens. With all other electrical stunning treatments, extracellular volume was immediately reduced in some but not all birds, and cardiac fibrillation or arrest was not often found. Ischemic conditions, caused by cessation of the circulation, stimulated this epileptic effect. A stunner setting of 150 V is therefore recommended to ensure immediate and lasting unconsciousness, which is a requirement for humane slaughter.

Animals↗

PubMed2002

Effects of feed deprivation and transport on preslaughter blood metabolites, early postmortem muscle metabolites, and meat quality.

In practice, poultry have their feed with drawn several hours before being collected and put on transport to the slaughter plant. With the exhaustion of their internal energy stores, the chickens may lack energy to cope with the conditions to which they are subjected. Meat quality is affected by the energy stored in the muscle at time of slaughter and its rate of decrease postmortem. Of 320 broiler chickens, half were subjected to 5 h feed deprivation whereas the others had access to feed until transport. In both groups, half the chickens were transported for 1.5 h, and the rest were transported within 5 min to the on-site slaughter facility. Twenty chickens were equipped with an ultrafiltration-collection device for monitoring glucose and lactate profiles. After slaughter, liver pH was measured. Stimulation of muscle metabolism was minimized by avoiding plucking. Breast muscle samples were taken at 0, 1, 2, 4, and 6 h and analyzed for pH and metabolite concentrations, and meat quality was measured at 96 h. Although liver glycogen was depleted in feed-deprived chickens, feed deprivation and transport for short periods were not found to affect blood glucose or lactate levels nor glycogen levels in the muscle at slaughter. Muscle carbohydrate metabolism was found to come to a complete halt after 6 h, which was not caused by exhaustion of the glycogen store but by the muscle's ability to generate adenosine triphosphate (ATP) after 4 h. At this time, rigor mortis had set in and deboning could be done without risk of cold shortening.

Abattoirs↗

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↗