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Submitted to: Aquaculture Conference Proceedings
Publication Type: Abstract Only Publication Acceptance Date: 11/17/2013 Publication Date: 2/25/2013 Citation: Weber, G.M., Hostuttler, M.A., Cleveland, B.M., Leeds, T.D. 2013. Growth performance comparison of intercross-triploid, induced-triploid, and diploid female rainbow trout Oncorhynchus mykiss. Aquaculture Conference Proceedings. P0326. Interpretive Summary: Technical Abstract: Triploidy is used in rainbow trout aquaculture as a means of inducing sterility to avoid the negative impacts of gonadal maturation on growth, fillet quality, and disease resistance; and for genetic isolation. Numerous studies have shown physiological differences between triploid (3N) and diploid (2N) fish, often associated with minimal ovarian development in female triploids. Also, cell size is larger and cell density is lower in most tissues of 3N fish compared to 2N fish. The impacts of these differences in physiology on performance traits must be understood to make the best use of triploidy to improve fish culture. An additional complication with triploidy is the common procedures for inducing triploidy require exposing the early embryo to a shock, usually high temperature or pressure (induced-triploid, 3NP), which in and of itself might impact development, physiology, and ultimately performance. An alternative method for making 3N fish is to first make tetraploid (4N) fish, which are fertile, and then cross the 4N fish with 2N fish to produce 3N offspring (intercross-triploids, 3NC). Few studies have been conducted comparing performance of 3NC with either 3NP or 2N fish. The objective of the current study was to compare growth performance in 2N, 3NP, and 3NC rainbow trout. Ten all-female families were created in which the 2N and 3NP animals were full siblings, and the 3NC animals were ¾ siblings to the other ploidy types. Fish from all families and ploidy types were raised in 3 communal tanks starting at 6 months post-hatching and up through spawning in March. The mean body weight of the 3NC fish matched or exceeded that of the other ploidy types throughout the study. Furthermore, mean family body weights were not correlated among ploidy types at ages up to 14 months post-hatching, but were highly correlated by 18 months post-hatching. Thus, the fastest growing families to about 1 kg and greater were similar regardless of ploidy type. Differences in organ weights among the ploidy types were observed. In addition, all intercross progeny were found to be 3N based on flow cytometry. |
