Animal & Avian Sciences Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/2741

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The effect of agonistic encounters on aggressive response in socially isolated Siamese fighting fish, Betta splendens
(2003-12-16) Charles, Debbie; Halperin, Janet R.P.; Estevez, Inmaculada; Animal Sciences
Male Siamese fighting fish were held for 7 to 10 weeks either in visually-social conditions (interact aggressively with a mirror image for 2 min, three times a week) or as visually-isolated fish (no aggression, saw only the back of a mirror). Phase I of this experiment investigated whether visually-isolated fish became hyper-aggressive, compared to visually-social fish. Aggression levels were tested with a series of models and mirrors. Social isolation did not affect duration or frequency of specific agonistic behaviors, nor of pooled behavioral categories (ANOVA, P > 0.05) within aggression tests. Phase II was to determine if aggression levels re-adjusted in visually-isolated fish experiencing live encounters among groups of 4 fish in naturalistic environments. Data was not significant unlike in previous isolation experiments (ANOVA, P > 0.05). However, several behavioral trends were observed that were consistent with previous isolation studies.
THE EFFECTIVENESS OF DUAL ENERGY X-RAY ABSORPTIOMETRY TO NON-INVASIVELY DETERMINE BODY COMPOSITION OF HYBRID STRIPED BASS
(2004-05-12) Wood, Sarah Ellen; Soares, Jr, Joseph H; Animal Sciences
The primary objective of this research project was to determine if dual energy x-ray absorptiometry was a valid method for non-invasively determining body composition of hybrid striped bass (Morone chrysops ♀ x. Morone saxatilis ♂). The first study utilized four dietary treatments to create a population with a broad range of body compositions. Fish were scanned using the Lunar model DPX-L dual energy x-ray absorptiometer in detailed medium and high resolution scan modes, manually analyzed for region of interest, in stacks, and scanned with a Hologic model QDR-4500A fan beam DXA. When compared to proximate analysis, results produced significant correlations and regression equations for: water and protein compared to lean, grams of fat, and ash compared to bone mineral composition. The second study utilized four dietary treatments of various energy:protein ratios to determine the ability of DXA to distinguish variations in body composition in accordance with dietary treatment. Fish were scanned with the Lunar model DPX-L DXA as well as the Lunar PIXImus DXA. The two scan values were compared to one another as well as to proximate analysis. Significant correlations and regression equations were calculated for the same comparisons as listed above. Fan beam DXA was less reliable as a predictor of body composition than pencil beam, and there was no difference between values from scan modes for the pencil beam DXA. PIXImus DXA was limited by size of the scan area, but was as successful as the larger pencil beam method for predicting certain parameters of body composition.
FUNCTIONAL STUDIES OF INFECTIOUS PANCREATIC NECROSIS VIRUS PROTEINS AND MECHANISM OF VIRUS-INDUCED APOPTOSIS
(2003-12-04) Song, Haichen; Vakharia, Vikram N; Animal Sciences
Infectious pancreatic necrosis virus (IPNV) encodes a 12 or 15-kDa nonstructural protein, known as VP5. To study the function of VP5, we generated three recombinant viruses rNVI15, rNVI15-15K, and rNVI15-ΔVP5, which could encode either 12-kDa VP5, 15-kDa VP5 or be deficient in VP5, respectively. VP5 was detected in rNVI15 and rNVI-15K infected cells but not in the cells infected with rNVI15-ΔVP5. However, the opal stop codon at nucleotide position 427 in rNVI15 virus was read-through, giving rise to a 15-kDa VP5 that is expressed poorly than rNVI15-15K virus-infected cells. All three recombinant viruses show similar replication kinetics in both Chinook salmon embryo (CHSE-214) and rainbow trout gonad (RTG-2) cells. Moreover, in Sp strains, IPNV segment A could encode a novel, putative 25-kDa protein from another ORF. This 25-kDa protein could not be detected in virus-infected cells, however, we could recover a mutant virus lacking this ORF, indicating that it is not essential for virus replication. To assess the molecular basis of virus adaptation in the cell culture, virulent rNVI15 was serially passaged in CHSE cells nine times to obtain a tissue-culture adapted virus, rNVI15TC. Comparison of the deduced amino acid sequences showed only one amino acid substitution at position 221 (Ala → Thr) in VP2. However, this adaptation mutation is only acquired in CHSE cells but not in RTG-2 cells. Two chimeric viruses, rNVI15ΔVP2 and rNVI15-15KΔVP2 were also generated, in which the residues at positions 217 and 247 in VP2 of the rNVI15 and rNVI15-15K viruses were replaced by the corresponding residues of an attenuated strain, Sp103. These two viruses have similar replication kinetics as Sp103, which replicates faster than rNVI15 in vitro, indicating that residues at positions 217 and 247 of VP2 may be the important markers for virus adaptation and attenuation in vitro. By generating a reassortant virus between rNVI15-15K and Sp103, we also demonstrate that VP1 is not involved in virus cell adaptation. The signal pathways and nature of IPNV-induced apoptosis were investigated in RTG-2 cells. IPNV-induced apoptosis occurs at the late stage of viral life cycle. Caspase-3 is activated during virus infection, and inhibition of caspase-3 could partially inhibit virus-induced apoptosis. Moreover, NF-κB activation is essential for IPNV-induced apoptosis, and it is involved in interferon-induced antiviral state. Both the NF-κB inhibitor and the antioxidant could inhibit NF-κB activity and apoptosis induced by IPNV infection, but they do not affect viral replication.
IMPLICATIONS OF DIVERGENT CORTISOL STRESS RESPONSIVENESS IN MALE STRIPED BASS (MORONE SAXATILIS)
(2003-12-18) Castranova, Daniel Anthony; Woods III, Lewis C; Animal Sciences
The aim of this study was to identify whether differences exist in reproductive and growth performance of male striped bass selected for high cortisol stress responsiveness (HCR) and low cortisol stress responsiveness (LCR), when exposed to standardized stress challenges before and during the spawning season. HCR (n=10) and LCR (n=10) were identified out of a population of 67 three-year-old striped bass males. Although no significant differences in weight, length, or coefficient of condition were found between HCR and LCR, HCR had a significantly greater specific growth rate when compared to LCR. Circulating levels of testosterone and 11-ketotestosterone were significantly higher in HCR than in LCR before and during the spawning season. HCR also had more fish spermiating across all sample dates compared to LCR. These results suggest that striped bass selected for high cortisol stress responsiveness have better reproductive and growth performance than fish selected for lower cortisol stress responsiveness.
QUALITY ASSESSMENT OF ATLANTIC STURGEON (ACIPENSER OXYRINCHUS) SPERMATOZOA UNDER CONDITIONS OF SHORT-TERM STORAGE
(2009) Dorsey, Kathryn Michelle; Woods, Curry; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Short-term storage trials were conducted in 2008 and 2009 on Atlantic sturgeon semen obtained from captive males, held at the U.S. Fish and Wildlife Service, Northeast Fish Technology Center, that were hormonally induced to spermiate; and wild males collected during the spawning season from the Hudson River. Samples were stored under refrigeration (4 + 1°C) in treatments consisting of different gaseous environments (oxygen, nitrogen or air) and experimental diluents (Modified Tsvetkova extender, Park & Chapman extender and neat, i.e. undiluted). Analyses of gamete quality were performed on day 0 (pre-treatment), and then every other day for 7 days in 2008 and for 21 days in 2009. Sperm quality parameters evaluated included: viability, motion analysis, curvilinear velocity and cellular ATP levels. Higher gamete quality was maintained when spermatozoa were diluted in the PC extender and stored in the presence of oxygen.