The trematode Bolbophorus damnificus (Digenea: Bolbophoridae) has deleterious effects on production efficiency of farm-raised catfish. The effects of B. damnificus on channel and hybrid catfish, as well as the prevalence and longevity of the trematode stages impacting production, are not well understood. This study aimed to understand the prevalence of infected snails, determine the longevity and site specificity of B. damnificus cercaria in catfish, and compare mortality and physiological response between channel and hybrid catfish during infection. The infectivity and survival of B. damnificus cercariae declined significantly at 12h intervals from 12-36h, and subsequent trials were standardized using cercariae <12h old. Metacercariae persisted in both fish types for 13 months and were found commonly in the posterior midsection. Hybrid catfish exhibited lower mortality than channel catfish. Exposed catfish exhibited anemia corresponding to parasite encapsulation, however no difference was found between fish types in physiological response during infection and subsequent recovery.

Oils from soybeans and catfish by-products were extracted using hexane, propane, and supercritical carbon dioxide (SCCO2). Free fatty acids (FFA), peroxide values (PV), anisidine values (AnV), total oxidation (TOTOX), induction point (IP), iodine values (IV), and 2-thiobarbituric acid reactive substance (TBARS) were all measured to analyze oxidation of these oils. The extraction yield of propane, hexane, and SCCO2 oils was 80.4, 94.5, and 90%, in respect to total lipid content. Oils extracted with SCCO2 were more oxidized than those extracted with propane and hexane; probably due to the higher temperature and longer extraction time. The IP correlated with AnV, IV, PV, and TBARS for soybean and catfish oils. These results suggest that IP is the optimum way to measure soybean and catfish oil stability.

Consumption of farm-raised catfish in the United States has increased over the last few decades. However, consumers usually prefer it as a deepried product, especially in the southern United States. The objective of this cross-sectional study was to determine the acceptability of lowat baked catfish using a Central Location Test. Subjects (n=137) tasted, compared, and evaluated samples of lowat baked catfish and deepried catfish. Results indicated that the fried product was favored (p <0.05) over the baked product. The majority of subjects (93.4%) identified the baked product as the healthier choice. Most subjects (85.7%) indicated that catfish was an overall healthy food choice. Reasons for consuming catfish included taste (75.6%), convenience (15.1%), health reasons (7.6%), and cost (1.7%). The majority of subjects (63.8%) indicated that they normally consumed catfish as a deepried product, but 91.9% indicated that they would be willing to consume catfish prepared in a lowat manner.

This study was undertaken in order to provide further insight into the effects of artificial heating on the fisheries of a small reservoir in the Southwest. The following specific objectives were established: (1) to map the reservoir for the distribution of heated water, (2) to determine the distribution of selected species of sports, rough, and forage fish in areas affected by the effluent and in areas not affected, (3) to compare size and condition of selected species of fish from areas affected by the effluent to size and condition of fish from areas not affected, and (4) to compare food habits of channel catfish in areas affected by the effluent to the food habits of channel catfish in areas not affected.

Digitized by Kansas Correctional Industries

The Northeastern region of Mexico has developed rapidly over the last few decades and reservoir construction has accompanied the growth of the region. As a result, recreational and sport fishing have become very popular. To regulate tournaments and to address growing exploitation concerns the Northeastern state of Nuevo Leon has begun to manage selected freshwater fisheries. Intensive management of warm water recreational species, however, does not have a long history in the region. This assessment was designed to evaluate the population structure and feeding habits of largemouth bass and channel catfish at a small rural fishery in Northeastern Mexico to get insight into mortality, growth, reproduction, and length related feeding patterns. Largemouth bass and channel catfish at La Juventud experience high mortality rates more than likely due to the selective removal of larger-older fish by angling. Extended spawning efforts at lower latitudes have also been implicated in accelerating the mortality of reproductively mature largemouth bass; however, studies regarding the onset, frequency, and duration of largemouth bass spawning in Northeastern Mexico are necessary to determine spawning seasonality and the adverse effects that extended reproduction efforts may have on growth potential. Largemouth bass grow fast during the first year of life and attain large sizes by age 1. Growth of young-of-year may benefit from an early onset of spawning and a long first-growing season, an abundant multi-species forage base of small fish, and frequent utilization of fish. Growth to age 3 and quality size (300 - 380-mm TL) is similar to that of populations from the Southeastern U.S.; however, the growth potential of individuals older than age 3 appeared limited by suitable sizes of prey. Channel catfish mean length-at-age values were similar to the mean of means for length-at-age-3 values of fish in Texas, and larger than the mean values from several regions in the Southern U.S.A. Largemouth bass at La Juventud may spawn early in the year (early spring or earlier than spring) and late in the year (fall). Spawning success; however, may be adversely affected by fluctuating water levels associated with an arid climate and undesirable interactions with other nest spawning species. Day-time gill net collections in 2006 and 2007 may have under sampled channel catfish. Gill net catches were low and variable; thus, interpretation of length, age, and weight data were constrained by small sample size.

Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains ix, 85 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.

Rapid expansion of the aquaculture industry in recent decades has resulted in infectious diseases emerging as a major constraint to fish production, causing large economical losses worldwide. Therefore, prevention practices are indispensable for maintaining the industry's profitability and sustainability. Vaccination is a proven effective strategy for disease control in aquaculture; however, improvements in vaccine efficacy are still needed. Because amino acid supplementation not only enhances fish growth but also immune responses, a series of experiments were conducted to test the hypothesis that dietary supplementation of arginine and glutamine, two amino acids with immunomodulatory roles, may promote growth and increase the efficacy of vaccination against Edwardsiella ictaluri in channel catfish. An initial experiment demonstrated that dietary arginine supplementation at 2 and 4% of diet enhanced growth and feed efficiency of channel catfish. Dietary arginine deficiency diminished plasma levels of arginine, citrulline, ornithine, glutamine and glutamate, and impaired innate performance of macrophages and neutrophils. In a separate experiment, dietary glutamine supplementation failed to enhance growth responses; however, supplementation at 2% of diet had strong positive effects on intestinal histology and enterocyte migration rate. In addition, serine, asparagine, glycine and threonine were increased in plasma of fish fed the diet with glutamine at 2%. A third experiment revealed that activated macrophages utilized large quantities of glutamine in media and to a lesser extent arginine. These two amino acids also were the most utilized by proliferating lymphocytes. Supplementing media with these amino acids positively modulated phagocytosis and bactericidal capacity of macrophages, as well as increased the proliferation rate of lymphocytes. A final experiment indicated that dietary supplementation of arginine (4%) and glutamine (2%) optimized the nutritional and immunological status of channel catfish, and enhanced responses to E. ictaluri vaccination. At the same time, this supplementation ameliorated some short-term adverse effects of vaccination on growth. Higher specific antibody titers, better lymphocyte responsiveness and survival to the bacterium were seen in vaccinated fish fed arginine- and glutamine-supplemented diets. These results support an expanded role of dietary arginine and glutamine manipulation as a tool to improve growth and vaccine efficacy of channel catfish.

Thesis (Ph.D.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references (ℓ. 104-128)

Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.