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|Title:||An Examination of the Basis for Poor Growth Performance in the Hybrid Grass Carp|
|Author(s):||Wike, Lynn Dell|
|Department / Program:||Animal Science|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
Agriculture, Fisheries and Aquaculture
|Abstract:||The hybrid grass carp (Ctenopharyngodon idella x Hypopthalmichthys nobilis) was once thought of as a viable alternative to the grass carp for controlling aquatic macrophytes. However, the hybrid proved a disappointment due to its poor growth performance and consumption rate. Investigation of the physiology, morphology, behavior, metabolism, and energy budgets of the hybrid and its parental species shows several traits being responsible for the hybrid's deficiency. Intermediacy of activity behavior, standard metabolism, and swimming efficiency, musculature similarity to the grass carp, and ineffective feeding morphology are the primary causes of the low energy intake and the large metabolic costs that effect the poor growth performance of the hybrid.
Intermediacy analysis of 30 traits, including biochemical, morphological, physiological, energetic, and behavioral parameters shows the hybrid to be intermediate for 16 of those traits. The remaining 14 nonintermediate characters are evenly divided in their similarity between the bighead and grass carp. It is concluded that the lack of luxuriance in the hybrid grass carp is a result of its metabolic and behavioral intermediacy and the mixed assortment of characters that supply it with the maternal musculature, paternal standard metabolism, and the herbivorous nature of the grass carp.
The hybrid, as the product of artificial hybridization and not of natural selection, is not adapted to the niche or trophic level of either parental species, even though it is primarily herbivorous. As an herbivore, it does not acquire adequate energy to support its metabolism and activity while providing energy for substantial growth.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987.
|Date Available in IDEALS:||2014-12-15|