Home About us Contact
|
Home About us Contact | ||
|
|
||
Wild Counterparts (wild + counterpart)
Selected AbstractsDiet-induced phenotypic plasticity in the skull morphology of hatchery-reared Florida largemouth bass, Micropterus salmoides floridanusECOLOGY OF FRESHWATER FISH, Issue 4 2005A. P. Wintzer Abstract , Hatchery-reared Florida largemouth bass, Micropterus salmoides floridanus, feed on inert pellet food while their wild counterparts capture elusive prey. Differences in levels of prey elusivity often mandate the use of alternate methods of prey capture. This study examines whether elusivity-based variation in prey capture translates to a phenotypic change during skull development, and if this change results in a functional difference in the feeding mechanism. The developmental pattern of the skull was conserved between hatchery and wild bass until 80,99 mm TL. At this point, wild bass quickly developed morphological changes of the jaw apparatus including a more fusiform head and elongated jaw structures. Natural development in hatchery bass, however, was retarded at this size. Post-release, the skulls of hatchery fish converged towards those of wild bass by 135 mm TL. Despite variation in skull development, no theoretical advantage in food capture was found between these two groups. Resumen 1. Los individuos de Micropterus salmoides floridanus criados en cautividad se alimentan de cápsulas inertes de comida mientras que sus congéneres salvajes capturan presas elusivas. A menudo diferencias en los niveles de elusividad de las presas permiten la utilización de métodos alternativos para capturar presas. Este estudio examina si la variación basada en la elusividad de la captura de presas se traduce en un cambio fenotípico durante el desarrollo del cráneo y si este cambio resulta en una diferencia funcional en el mecanismo de alimentación. 2. El patrón de desarrollo del cráneo se mantuvo entre individuos criados en cautividad y en individuos salvajes hasta los 80,99 mm longitud total. En este punto, los individuos salvajes desarrollaron rápidamente cambios en el aparato mandibular incluyendo una cabeza más fusiforme y estructuras mandibulares mas alargadas. Sin embargo, en individuos de cautiverio, el desarrollo natural se retrasó en este tamaño. 3. Tras una suelta, los cráneos de individuos procedentes de cautiverio convergieron hacia los individuos salvajes en los 135 mm longitud total. A pesar de la variación en el desarrollo del cráneo, no encontramos ninguna ventaja teórica en la captura de alimento entre estos dos grupos. [source] Rearing Environment Affects the Brain Size of Guppies: Lab-Reared Guppies have Smaller Brains than Wild-Caught GuppiesETHOLOGY, Issue 2 2009James G. Burns Animals bred for captivity often have smaller brains and behave differently than their wild counterparts. These differences in brain size have been attributed to genetic changes resulting from, for example, inbreeding depression and pleiotropic effects of artificial selection for traits such as docility. A critical question, though, is whether these differences in brain size are due to plastic responses to the environment, not just genetic changes. We observed a large reduction in brain size in first generation, lab-reared female guppies compared with wild-caught ones (19% smaller telencephalon, 17% smaller optic tectum). We then reared first-generation, lab-born guppies in environments varying in spatial complexity and size in an attempt to isolate factors that might increase brain size and change temperament, but no significant differences in phenotype were observed. The results of these experiments show that, although the environmental factors responsible for the effect have not been found, even first generation lab-reared individuals can have smaller brains than wild individuals. [source] Transgenic fish: an evaluation of benefits and risksFISH AND FISHERIES, Issue 2 2000N. Maclean Transgenic fish have many potential applications in aquaculture, but also raise concerns regarding the possible deleterious effects of escaped or released transgenic fish on natural ecosystems. In this review the potential applications of transgenic fish are considered, the probable benefits reviewed, the possible risks to the environment identified and the measures which might be taken to minimize these risks are evaluated. Growth trials of transgenic fish have already been carried out in outdoor facilities and some of these are discussed in the light of possible risks and benefits. Regarding the hazards associated with release or escape, whilst there is some evidence to suggest that transgenic fish may be less fit compared to their wild counterparts, there is insufficient evidence to say that this will be true in all cases. Using mathematical models, we have attempted to predict the magnitude of the genetic effects in a range of different scenarios. A number of possible containment techniques are considered, amongst which containment by sterility is probably the most promising. This can be engineered either by triploidy or by transgenic methods. The conclusions include a tabulated balance sheet of likely benefits and risks, with appropriate weighting. [source] Effects of differences in diet and seasonal changes on the fatty acid composition in fillets from farmed and wild sea bream (Sparus aurata L.) and sea bass (Dicentrarchus labrax L.)INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2008Mustafa Yildiz Summary The effects of dietary fatty acids and seasonal variation on the fatty acid profiles of farmed and wild sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) were determined by analysis of their fillets. Farmed sea bream and sea bass were fed on the same commercial feeds all year. Fatty acid profiles in the fillets reflected the fatty acid profiles of the commercial feeds. The predominant fatty acids in the trial feeds, fillets of farmed and wild sea bream and sea bass were 16:0, 18:1n -9, 18:2n -6, 20:5n -3 and 22:6n -3. The fatty acid profiles in the fillets of farmed sea bream and sea bass did not differ (P > 0.05) except in the winter season compared with those of their wild counterparts. However, the content of eicosapentaenoic acid (20:5n -3), docosahexaenoic acid (22:6n -3) in the fillets of the farmed and wild sea bass were significantly (P < 0.05) higher than the farmed and wild sea bream. The wild sea bream had significantly (P < 0.05) higher total saturated fatty acid and monounsaturated fatty acid (MUFA) levels, and lower total n -6 and n -3 polyunsaturated fatty acid (PUFA) levels in winter than in the summer and spring seasons. Similarly, in the fillets of wild sea bass, total n -3 PUFA levels were significantly (P < 0.05) lower, and the MUFA levels were higher in winter than in the other seasons. These results indicate that the farmed fish fillets were good sources of n -3 PUFA in each of the three seasons. However, wild fish were good sources of n -3 PUFA in the spring and summer. [source] Leptin, body composition, adrenal and gonadal hormones among captive male baboonsJOURNAL OF MEDICAL PRIMATOLOGY, Issue 6 2003M.P. Muehlenbein Abstract:, Morphometric and hormonal measures were collected from 21 captive savanna baboons (Papio cynocephalus) maintained at the Tulane National Primate Research Center in order to determine age-related patterns in leptin levels over the life course as well as their relationships to body composition and adrenal and gonadal steroids. Comparison of leptin levels between peri-pubertal, adolescent, young adult, and fully mature males show lower levels among adolescent as compared with young adult males (P = 0.05 by Kruskal,Wallis ANOVA). In addition, abdominal fat varied among age groups (P = 0.003 by Kruskal,Wallis ANOVA) with the peri-pubertal animals lower than the adolescents, young adults, and prime adults. However leptin was not related to any measure of body composition, including abdominal fat, or to adrenal hormones (dehydroepiandrosterone, dehydroepiandrosterone-sulfate, and cortisol) or gonadal hormones (testosterone and estradiol). Age-related changes in leptin appear similar to those reported for captive rhesus macaques, while the failure to find an association between leptin and abdominal fat is interestingly different. These results confirm elevated levels of leptin in captive baboons compared with their wild counterparts and suggest that they result from changes in fetal development. [source] IMPACT OF FREEZING TEMPERATURE ON QUALITY OF FARMED ATLANTIC COD (GADUS MORHUA L.)JOURNAL OF TEXTURE STUDIES, Issue 4 2007TURID MØRKØRE ABSTRACT This study evaluates the impact of freezing temperature (,10,,25,,40,,55 or,70C) on thaw exudates, liquid leakage during freeze-chilling, appearance, gaping and mechanical properties of farmed Atlantic cod fillets. Freezing temperature significantly influenced each of the characteristics studied. High temperatures (,10 and,25C) gave increased thaw exudates, and freezing at,10C gave the highest liquid leakage during freeze-chilling. Fillets frozen at,10C had the lowest gaping and the whitest appearance. The results indicated the highest degree of toughening upon freezing at,10 or,55C, whereas the degree of toughening appeared to be similar and lower for fillets frozen at,25,,40 or,70C. The impact of freezing temperatures on the quality of farmed cod therefore appeared to be complex, but no overall beneficial effects were found by decreasing the freezing temperature below,40C. PRACTICAL APPLICATIONS For the fish processing industry, it is important to define optimal freezing and frozen storage regimes that are cost efficient and at the same time preserve the fresh fillet quality. Farmed cod differ from their wild counterparts by having lower water content, lower muscle pH and thicker fillets. Hence, industrial guidelines for wild cod may not be transferable to farmed cod. This study showed no beneficial effects by decreasing the freezing temperature below ,40C. Freezing and frozen storage are usually separated commercially. Results from the present study give valuable contribution to future studies aiming at defining optimal combination of freezing and frozen storage temperatures for farmed Atlantic cod. [source] Hatching asynchrony and growth trade-offs within domesticated and wild zebra finch, Taeniopygia guttata, broodsBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2010MARK C. MAINWARING The Australian zebra finch, Taeniopygia guttata, is a widely used model organism, yet few studies have compared domesticated and wild birds with the aim of examining its relevance as an evolutionary model species. Domestic and wild broods hatch over approximately 4 and 2 days, respectively, which is important given that nestlings can fledge after as little as 12 days, although 16,18 days is common. We aimed to evaluate the extent to which the greater hatching asynchrony in domestic stock may effect reproductive success through greater variance in size hierarchies, variance in within-brood growth rates, and partial brood mortality. Therefore, by simultaneously controlling brood sizes and experimentally manipulating hatching intervals in both domesticated and wild birds, we investigated the consequences of hatching intervals for fledging success and nestling growth patterns, as well as trade-offs. Fledging success was similarly high in domestic and wild broods of either hatching pattern. Nonetheless, between-brood analyses revealed that domestic nestlings had significantly higher masses, larger skeletal characters, and longer wings than their wild counterparts, although wild nestlings had comparable wing lengths at the pre-fledging stage. Moreover, within-brood analyses revealed only negligible differences between domestic and wild nestlings, and larger effects of hatching order and hatching pattern. Therefore, despite significant differences in the hatching intervals, and the ultimate size achieved by nestlings, the domestication process does not appear to have significantly altered nestling growth trade-offs. The present study provides reassuring evidence that studies involving domesticated zebra finches, or other domesticated model organisms, may provide reasonable adaptive explanations in behavioural and evolutionary ecology. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 763,773. [source] | |||||||||||||