Supplementing rainbow trout (Oncorhynchus mykiss) broodstock diets with choline and methionine improves growth in offspring

Authors: Cleveland, Beth; Leeds, Timothy - Tim; PICKLO, MATT - US Department Of Agriculture (USDA); BRENTESEN, CARLEY - US Department Of Agriculture (USDA); FROST, JASON - US Department Of Agriculture (USDA); BIGA, PEGGY - University Of Alabama

Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2019
Publication Date: 6/20/2019
Citation: Cleveland, B.M., Leeds, T.D., Picklo, M., Brentesen, C., Frost, J., Biga, P. 2019. Supplementing rainbow trout (Oncorhynchus mykiss) broodstock diets with choline and methionine improves growth in offspring. Journal of the World Aquaculture Society. 50(3):1-16. https://doi.org/10.1111/jwas.12634.
DOI: https://doi.org/10.1111/jwas.12634

Interpretive Summary: Gonad development in fish is characterized by deposition of nutrients into the eggs which provide nutritional requirements for the developing embryo and fry. During embryonic development and for several weeks post-hatch, salmonid larvae depend on egg-derived nutrients for survival, therefore the egg must have a complete nutritional profile for optimal growth and development. The maternal broodstock diet can impact the nutrient profile of the egg, therefore it is of value to identify broodstock feeding strategies that benefit performance of the offspring generation. This study determined that supplementing rainbow trout broodstock diets with two micronutrients, choline and methionine improved body weight in offspring by approximately 15% at the 950 g harvest size. These findings indicate the potential for interventions in broodstock nutrition as a feeding strategy to improve growth performance in the next generation.

Technical Abstract: Nutritional programming represents that mechanism through which broodstock feeding strategies can have lifelong effects in the offspring generation. However, little is known regarding how these strategies can be utilized in aquaculture as an approach to improve production traits. The objective of this study was to determine whether supplementing female rainbow trout broodstock diets with choline, methionine, or a combination affects offspring growth performance. Four treatment diets were produced by top-dressing a commercially available finfish broodstock diet with 1) 12,000 ppm methionine, 2) 7,400 ppm choline, or 3) 12,000 ppm methionine and 7,400 ppm choline. The fourth diet was the base-diet top dressed by the nutrient vehicle (distilled water) and served as the control. Six female rainbow trout families were fed treatment diets beginning 18 months post-hatch through spawning. Oocytes were fertilized using milt from a single family of unrelated males. All offspring consumed a commercial feed and fork length and body weight were recorded bimonthly. Broodstock diet did not affect maternal body weight, body condition, egg size, or egg yield at spawning, however eggs from choline-treated broodstock contained 10% more choline than eggs from control broodstock. Offspring fry from choline-treated broodstock were smaller than fry from the control broodstock at 146 days post hatch (dph). However, at the final harvest (439 dph, ~950 g) offspring from broodstock on the non-supplemented control diet weighed between 12 – 18% less than offspring from supplemented diets. There was a significant diet by family interaction on body weight and length; supplemented diets improved offspring growth in only three of the six broodstock families. These findings indicate that supplementing broodstock diets with methionine and choline, independently and in combination, produce a nutritional programming effect that benefits growth in offspring.