Submitted to: Aquaculture
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/21/2009
Publication Date: 9/21/2009
Citation: Wolters, W.R., Barrows, F., Burr, G.S., Hardy, R.W. 2009. Growth Parameter of Wild and Selected Strains of Atlantic Salmon (Salmo salar) on Two Experimental Diets. Aquaculture. 297:136-140. Interpretive Summary: Atlantic salmon aquaculture is one of the most successful global aquaculture enterprises, and has wide acceptance as a main food item by American consumers. Increases in production and efficiency in aquaculture must continue in order to meet the increasing demand for seafood in the future. This goal will be successful only if increased growth and production efficiency is solved with appropriate technologies developed and transferred to commercial industries. Improvements in selective breeding and nutrition have already been successful in improving production efficiency. Genetic improvement made in breeding programs for cultured salmon and related species has been successful and led to the development and transfer improved germplasm to commercial industry. Therefore, it is important to continually evaluate fish stocks involved in breeding programs with current diets and also assess the proportion of gains from selective breeding and diet modifications. The objective of the present study was to compare a traditional high protein-lower energy salmon diet to a newer lower protein-high energy diet on growth and body composition of two Atlantic salmon strains, a commercially farmed St. John’s River strain and a wild Penobscot River strain. The St. Johns River strain had significantly greater growth compared to the wild Penobscot River strain for both diets. Saint John’s River fish fed the newer lower protein-high energy diet also had greater growth compared to fish fed the traditional high protein-lower energy diet. Diet type did not affect the growth of Penobscot River fish. These results indicate that breeding programs using St. River’s Atlantic salmon have been successful to increase growth rates compared to a wild population, and new diet formulations have also increased growth rates for farmed salmon. Overall differences in final weight were 85.5% variation from strain differences and 14.2% from diet differences.
Technical Abstract: Atlantic salmon parr from Penobscot (wild) and St. John’s River (selected) strains were cultured in 0.265m3 tanks filled with 2-3 ppt salinity well water and connected to a common bio-filter system. Salmon parr were stocked at 100 fish/tank and fed one of two experimental diets in a 2 x 2 factorial design with 4 replicate tanks for each treatment. Each strain was fed diet formulated to represent either a traditional high protein (THP), lower energy salmon diet (46% protein, 18% fat) or a newer high energy diet (NHE) (40% protein, 32% fat). Fish were anesthetized, counted and weighed at approximately 2 week intervals during the 23 week trial. Analysis of variance found significant differences due to strain on initial weight, final weight, specific growth rate, % feed consumed per day, and thermal growth coefficient. St. John’s strain salmon were larger at the end of the trial (117.2+2.5g) than Penobscot River salmon (71.2+2.5g). There was a significant effect of diet on day 163 weight, specific growth rate, and thermal growth coefficient. There was no effect of strain, diet or interaction of the variables on feed conversion. Although diet had a significant effect, final weight was affected by diet only for St. John’s River fish (99.0+2.0 and 89.4+2.0g). Strain differences accounted for 85.9% of the difference in 163 day weight compared to 14.2% due to diet. Results indicate St. John’s River salmon, which are commercially cultured and are being used in selective breeding programs, have superior growth compared to wild, unselected Penobscot River salmon. St. Johns River salmon fed NHE grew significantly faster than St. Johns River salmon THP. The slower growing Penobscot fish grew at the same rate when fed either the THP or NHE diet.