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The effect of dietary protein source on plasma parameters related to stress and behaviour in pigs varying in their susceptibility to stress /Roberts, Susan January 1992 (has links)
The present study was performed to determine if pigs varying in their susceptibility to stress, adapted to a casein-based diet, experience an improvement in biochemical parameters related to stress and behaviour compared to pigs adapted to the traditional western canadian cereal-based swine diet. Experiment 1 involved separating fifty-eight, 8-week old pigs according to genotype with respect to the halothane gene. Within each genotype pigs were divided into 2 groups and assigned to either a control diet or to a diet where most of the protein source was substituted for casein. All animals were adapted to diet for 6 weeks and experienced a weekly blood sampling stressor. Day 1, 14 and 35 of the plasma samples were analyzed for glucose, cortisol, ACTH, insulin, pyridoxal 5$ sp prime$-phosphate (PLP), amino acid concentrations and dopamine-$ beta$-hydroxylase (DBH) activity; metabolic indices known to be responsive to stress. Experiment 2 involved separating fifty-seven, 14-week old pigs in the same manner, then adapting the pigs to their respective diets for a period of 4 weeks. Afterwards, pigs were transferred from their pen to a novel pen-maze situation where they had their behaviour monitored for a period of one hour. Results of these experiments have revealed that (1) the stress susceptible and carrier pigs experienced reduced day 35 plasma glucose, PLP concentrations and DBH activity compared to normal pigs; (2) dietary adaptation to the casein diet resulted in greater day 14 and 35 PLP levels and day 35 essential amino acid lysine, threonine, methionine, tryptophan and arginine concentrations compared to control-adapted pigs; (3) the carrier pigs investigated their surroundings more frequently than the stress susceptible pigs, and the normal pigs engaged in the through-maze behaviour more often than the stress susceptible pigs; and (4) adaptation to the casein diet, compared to the control diet, resulted in fewer displacement-type behaviours such as drinking
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The effect of dietary protein source on plasma parameters related to stress and behaviour in pigs varying in their susceptibility to stress /Roberts, Susan January 1992 (has links)
No description available.
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Genomic characterisation and antimicrobial resistance profiles of Listeria monocytogenes isolated from pig farmsMasemola, Puseletso Maselepe 07 1900 (has links)
Listeria monocytogenes is a zoonotic foodborne pathogen, transmissible from the natural
agricultural environment to animals and humans. In recent years, the pig production industry has
experienced a series of monetary losses as a result of the L. monocytogenes outbreak which
threatened the economy of South Africa. This outbreak also had a detrimental effect on the health
system of the country. In South Africa however, there is limited information regarding the genomic
diversity of L. monocytogenes. Therefore, an overview of the genomic diversity of L.
monocytogenes strains circulating at different levels of the pork production chain needs to be
determined so as to be able to identify routes of contamination of the pathogen and thus improve
meat safety. This study was aimed to determine the antimicrobial resistance patterns and
population structure of L. monocytogenes isolated from pig farms in South Africa. Based on wholegenome
sequence analysis, 77 isolates of L. monocytogenes were differentiated into four molecular
serogroups with IIa (45.5%) being the most prevalent followed by IIc (26.0%), IVb (22.1%) and IIb (6.5%). Overall, 11 clonal complexes (CCs) were identified in this study, with the
predominance being observed from; CC204 (23.4%), CC1 (19.5%) and CC2 (16.9%). Genetic
elements associated with biocide, antimicrobial and heavy metal resistance were noted in 24.7 %,
48% and 11.7% of the isolates, respectively. Listeria pathogenicity island 1 and 3 that harbored
clusters of virulence genes were present in 38.8% of the isolates. Five different plasmids were
found in 68.9% of the isolates. This study has given baseline data on the genomic diversity of L.
monocytogenes strains that are associated with biocides, heavy metal and antibiotics resistance
genes. The data again demonstrated the genotypes of L. monocytogenes that are prone to
contaminate the farm environment and possibly cause diseases in animals and humans. / Life and Consumer Sciences / M. Sc. (Life Sciences)
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