Digitized by Kansas Correctional Industries

Prerigor pressurization of bovine semimembranosus muscle at 103.5 MNm⁻² (15,000 psi) for two min at 35°C significantly decreased (P<0.01) muscle pH, and significantly (P<0.01) increased the rate of glycogen degradation during the first 4 hr postmortem. Glycogen levels of pressurized muscle were significantly (P<0.01) lower than those of the control at 1, 2 and 4 hr postmortem. Glucose concentrations were significantly (P<0.01) higher in the treated muscle than in the control at all sampling periods. Until 4 hr postmortem the level of glucose-6-phosphosphate was higher in pressure-treated muscle than in the control. Lactate content increased rapidly after pressurization (1 hr postmortem), resulting in an immediate drop in pH; however, there was no significant difference between control and treated muscles at 24 hr. Pressurized muscle showed a significant (P<0.01) increase in lactate dehydrogenase activity over that of the control muscle at 1 hr but not at 24 hr. Pressurization accelerated catabolism of both creatine phosphate and adenosine triphosphate which resulted in a higher ATP turnover value than that of the control. R-values (a measure of metabolic rate) were significantly correlated (r=-0.95) with degradation of ATP. CPK activity was significantly higher (P<0.01) in pressurized muscle than in the control at 1 hr postmortem but not at 24 hr. Concentrations of ATP, adenosine diphosphate (ADP), adenosine monophosphate (AMP), inosine monophosphate (IMP), bases and nucleosides (adenosine, adenine, inosine, hypoxanthine) and nicotinamide adenine dinucleotide (NAD) were determined by high pressure liquid chromatography. Pressurization completely depleted the ATP supply and increased the IMP concentration at 1, 4 and 24 hr postmortem. At 24 hr postmortem, control samples had more ADP whereas the AMP concentration was higher in the pressurized samples at 1 hr postmortem but not at 24 hr. Concentrations of bases and nucleoside metabolites and NAD did not differ between treatments. / Graduation date: 1984

The fate of cetacean carcasses in the deep-sea was investigated using autonomous lander vehicles incorporating time-lapse camera and acoustic tracking systems, as well as fish and amphipod traps. Four lander deployments placed cetacean carcasses at depths of 4000-4800m in the Northeast Atlantic for periods of 36h, 152h, 276h and 480h, before being recovered. The photographic sequences revealed that the soft tissue of carcasses was consumed at rates varying from 0.05-0.48kg.h-1, depending on how intact the carcass was. In each deployment, approximately 1h after emplacement, the grenadier Coryphaenoides (Nematonurus) armatus and large numbers of lysianassid amphipods had arrived at the food-fall. Amphipods appeared to be the only scavengers able to feed directly on the carcass. They tunnelled through the skin and connective tissue layer to reach the blubber and muscle, which was consumed in preference to anything else. Despite being unable to feed on the carcass directly, grenadier numbers remained high until the majority of the bait had been consumed. They were believed to be preying on amphipods attracted to the food-fall. Acoustic tracking studies suggested that, although overall fish numbers remained high during this phase, individuals did not stay significantly longer at the site of the large food-fall compared to a small one, and a "conveyer-belt" of fish arrived, fed and dispersed on a scale of 10s to 100s of km. Once the soft tissue had been removed, grenadier numbers declined and mobile scavengers were replaced by a variety of more benthic fish and invertebrates, some of which took up residence amongst the bones, e.g. eelpouts and galtheid crabs. Funnel traps recovered with the carcass and from a series of fish trap deployments of varying duration indicated a succession in species composition of amphipods, with specialist necrophages such as Eurythenes gryllus and Paralicella sp. being replaced by more generalist feeders of the Orchomene species complex.

No description available.

The basic objective of this thesis was to estimate the economic effects of yield grade standards for carcass beef on the various market sectors of the Canadian beef industry. The adoption of the standards was expected to enhance consumer demand, improve efficiency within the processing and marketing services sectors, and improve resource allocation and revenues of livestock producers. A conceptual model showing the interrelationships among market sectors was developed and formulated into a system of equations for econometric estimation. The model contained variables relating to the supply and demand of market participants affected by the change in grading standards. Measurement of these variables was based on published quarterly data, including four years of yield grading, over the 1961-76 period. The statistical results showed a significant economic variables relating to the supply and demand of market participants affected by the change in grading standards. Measurement of these variables was based on published quarterly data, including four years of yield grading, over the 1961-76 period. Binary variables were incorporated in the model to identify any structural change in the relationships coincident with the grade change. Problems in estimation arose due to the simultaneous nature of the model, and intercorrelation problems involving predicted prices for adjacent market levels in certain structural equations. Two alternative specifications of the processing and marketing services relationships were formulated to address this problem. First, variables relating to demand at the adjacent market level were substituted for the corresponding price. The second method involved the ratio of adjacent market level prices. Both specifications resolved the problem,, but in the substitution case intercorrelation was transferred to other variables. Estimates of the parameters of the various equations were obtained by using the two stage least squares regression procedure. The statistical results showed a significant economic impact of yield grades, as measured by the slope and intercept binary variables, in the estimated retailer demand and producer supply equations. But, these results cannot be considered conclusive. A lack of information concerning impact of yield grades, as measured by slope and intercept binary variables, in the estimated retailer demand and producer supply equations. But, these results cannot be considered conclusive. A lack of information concerning historical costs in the processing and marketing sectors necessitated the use of proxy variables which may not have accurately captured the full impact of the grade change. A further problem was that potential yield grade adjustments in carcass weights were dominated by the effects of rapidly rising feed grain prices throughout the grade change period. / Graduation date: 1982

No description available.

No description available.

No description available.

Typescript (photocopy). / Digitized by Kansas State University Libraries

published_or_final_version / Zoology / Master / Master of Philosophy