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Biomedical subjects

C Pieterse

Publications and source records attributed to C Pieterse.

7 recordsLinked to original sources
PubMed2000

[Review of the production of ostrich meat].

Ostrich meat was originally considered to be a by-product of the leather industry. Ostrich farming focused on the production of good quality hides and was mainly based on experience. Since a few years there has been a move from hide production to meat production; however, little is known about ostrich meat production which has consequences for legislation. There is insufficient knowledge about the factors influencing muscle growth. The strong growth of ostrich meat production in the EU member states should be discussed because the climatic conditions are not optimal and the price of the meat may remain high compared to meat of broilers, pigs, and cattle. Information programmes have to be set up for all members in the production chain. The present method for stunning of ostriches has to be changed in most slaughterhouses. In this study the effects of electrical and mechanical stunning on unconsciousness, duration of unconsciousness, behaviour, and meat quality parameters were examined. At least 500 mA is needed to stun ostriches effectively, and they can be killed using a short-stick interval or a long stunning duration. A modified captive needle pistol, using air pressure, is an alternative to electrical head-only stunning.

Abattoirs↗
PubMed2000

Behavioral responses of broilers to different gaseous atmospheres.

This study was conducted to determine the differences in behavioral response of broilers when they come into contact for the first time with gas mixtures that can be used for stunning. The six test groups were divided into four experimental groups that were exposed to gas mixtures used for stunning and two control groups that were exposed to atmospheric air. The different gas mixtures and their concentrations were a) air, no flow (control-); b) circulating air, flowing (control+); c) >90% Ar in air; d) 60% CO2 in air; e) 40% CO2 and 30% O2 in air; and f) 70% Ar and 30% CO2 in air. The behavior of the broilers before entering the gas tunnel, the number of birds that moved into the gas mixture, and the behavior in the gas mixture were recorded on video and analyzed afterward. No differences among the groups were observed in the number of broilers that walked into the gas tunnel or in the number of birds that tried to return to the cage. Exposure of broilers to the 70% Ar and 30% CO2 mixture resulted in the fastest loss of posture. The number of broilers exhibiting headshaking and gasping was least in the >90% Ar in air mixture. Convulsions were rarely seen in the 40% CO2 and 30% O2 mixture; the other gas mixtures resulted in severe convulsions. The experiment did not indicate that broilers could detect or avoid increased CO2 or decreased O2 levels when they come into contact with such atmospheres for the first time.

Administration, Inhalation↗
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↗
PubMed1999

The effects of captive bolt and electrical stunning, and restraining methods on broiler meat quality.

The effects of captive bolt stunning using air pressure, compared to electrical water bath stunning, on broiler carcass and meat quality were evaluated. The birds were shackled or placed in a cone. Two trials were conducted using a total of 160 female broilers. The four stunning-restraining treatments were whole-body electrical stunning (10 s, 110 mA, 300 Hz) in a water bath or air pressure stunning (0.5 s, 2 atm) while broilers were shackled by their feet or placed in a cone. Air pressure stunning caused a higher (P < 0.01) degree of convulsions and a lower (P < 0.01) degree of blood loss than electrical stunning, and reduced the prevalence of broken clavicles (P < 0.05) and coracoids (P < 0.01). Blood loss of shackled broilers was slightly higher (P < 0.05) than those restrained in a cone. Air pressure stunning resulted in significantly (P < 0.01) lower pH values and hemorrhaging in filets and thigh muscles than electrical stunning. The incidence of thigh muscle hemorrhaging was significantly (P < 0.01) reduced when broilers were restrained in a cone compared to being shackled. The stunning and restraining treatments did not result in differences in cooking losses. The filets from shackled birds were judged more tender than the filets from cone-restrained birds. With respect to the effect of stunning method, the filets of air pressure stunned birds was judged more tender than the meat from electrically stunned birds. Captive bolt stunning using air pressure has benefits over electrical stunning; however, a suitable stunning and restraining device remains to be developed.

Abattoirs↗
PubMed1998

Changes in the somatosensory evoked potentials and spontaneous electroencephalogram of broiler chickens during exposure to gas mixtures.

1. Six week-old broiler chickens implanted with electroencephalogram (EEG) recording and somatosensory stimulating electrodes were exposed to either 90% argon in air, a mixture of 30% carbon dioxide and 60% argon in air or a mixture of 30% oxygen and 40% carbon dioxide (balance nitrogen) for 2 min, to determine the times to onset of changes in spontaneous EEG and the loss of somatosensory evoked potentials (SEPs) and thus unequivocal loss of consciousness. 2. In addition, after a 2 min exposure to the carbon dioxide-oxygen mixture, some broilers were allowed to recover in air and their EEGs and SEPs were continuously recorded until the return of normal EEG and SEPs. During this period, the time to return of response to comb pinching was also determined in 10 broilers. 3. All broilers exposed to either argon or the carbon dioxide-argon mixture died within 2 min, whereas, only 3 out of 17 broilers died during the 2 min exposure to the carbon dioxide-oxygen mixture. 4. During exposure to argon, unlike the other 2 gas mixtures, the majority of broilers showed high amplitude, low frequency electrical activity in the EEG on average at 10 s. The mean times to onset of EEG suppression were 17, 19 and 40 s after exposure to argon, the carbon dioxide-argon mixture and the carbon dioxide-oxygen mixture, respectively. An isoelectric EEG occurred on average at 58 and 41 s after exposure to argon and the carbon dioxide-argon mixture, respectively. An isoelectric EEG did not occur in broilers which were exposed to the carbon dioxide-oxygen mixture. 5. The SEPs were abolished in broilers on average 32 and 24 s after exposure to argon and the carbon dioxide-argon mixture, respectively. During exposure of broilers to the carbon dioxide-oxygen mixture the SEPs were abolished in the majority of birds on average at 47 s, however, 2 out of 14 birds retained their SEPs for the entire period of 2 min exposure to this gas mixture. 6. During the recovery after exposure to the carbon dioxide oxygen mixture, response to comb pinching and SEPs returned either at the time of, or soon after, the onset of high frequency electrical activity in the suppressed EEG of broilers. The mean times to return of response to comb pinching and SEPs were 52 and 43 s, respectively. 7. Based on the time to onset of EEG suppression or loss of SEPs, exposure of broilers to either 90% argon in air, or a mixture of 30% carbon dioxide and 60% argon in air, resulted in quicker loss of consciousness than during exposure to a mixture of 40% carbon dioxide, 30% oxygen and 30% nitrogen. The time to return of consciousness after a 2 min exposure to the carbon dioxide-oxygen mixture was also found to be rapid.

Animals↗
PubMed1995

Stressful life events and psychological status in black South African women.

The relationship between stressful life events and psychological status in Black South African women was explored, using a semistructured interview that consisted of a demographic questionnaire; the Xhosa Life Event Scale (XLES; Swartz, Elk, Teggin, & Gillis, 1983), which comprises mainly personal stressors; the Township Life Event Scale (TLES; Bluen & Odesnik, 1988), which comprises mainly sociopolitical stressors; and the General Health Questionnaire (GHQ, Goldberg, 1972, 1978). The participants were a random sample of 100 Black women living in a South African township. There were significant positive correlations between psychological distress and (a) undesirable life changes, (b) recurring stressful events of a sociopolitical nature (but not of a personal nature), and (c) continuous stressful events of a sociopolitical nature (but not of a personal nature). The results indicated that adverse sociopolitical conditions and the stress that accompanied them had a stronger negative effect than stressful events of a personal nature did on the women's mental health.

Adult↗