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ARS Home » Southeast Area » Auburn, Alabama » Aquatic Animal Health Research » Research » Publications at this Location » Publication #207613
Title: Effect of Distillers Dried Grain with Solubles Incorporated Diets on Growth, Immune Function and Disease Resistance in Nile tilapia

Author
item Shelby, Richard
item Lim, Chhorn
item Aksoy, Mediha
item Klesius, Phillip

Submitted to: Aquaculture Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/8/2008
Publication Date: 11/1/2008
Citation: Shelby, R.A., Lim, C.E., Aksoy, M., Klesius, P.H. 2008. Effect of distillers dried grain with solubles incorporated diets on growth, immune function and disease resistance in Nile tilapia. Aquaculture Research. 39:1351-1353.

Interpretive Summary: This research studied the effects of adding distiller's grains with solubles (DDGS) as a feed ingredient in the diets of young Nile tilapia (Oreochromis niloticus). This coproduct of the ethanol industry is now widely used as an animal feed ingredient and is a source of protein and other nutrients, but may be deficient in the amino acid lysine. The effects of DDGS on the tilapia immune system and disease resistance were also studied because the yeast component of DDGS contains b-glucans which have been reported to boost immune response in a number of species. We prepared 5 diets for Nile tilapia with 0%, 30% and 60% DDGS, with and without added lysine, and the balance of the protein coming from soy meal. Juvenile Nile tilapia were fed these diets for 12 weeks. Weight gain and feeding efficiency of the diets were not significantly different from the fish consuming the soy protein control diet, except for the diet with 60% DDGS without added lysine, which was lower weight gain and feeding efficiency. Measurements of immune function such as blood cell counts, oxidative burst activity, plasma lysozyme, complement, or globulin protein measurements were not different among fish consuming the diets. A disease challenge of the fish with Streptococcus iniae resulted in an overall mortality of 55%, however there were no differences between diets. We conclude that DDGS can partially substitute for soy protein in tilapia diets at a ratio of up to 60% with the addition of lysine. Furthermore, the yeast component of DDGS does not appear to have significant impact on immune function or disease resistance against S. iniae in juvenile Nile tilapia.

Technical Abstract: Distillers dried grains with solubles (DDGS) is a coproduct of the ethanol industry which is now widely used as a feed ingredient. The protein in DDGS may partially substitute for soy protein in fish diets with some cost savings. Other natural ingredients, particularly b-glucans, in DDGS may have beneficial effects such as enhanced immune response. We prepared 5 isocaloric diets for Nile tilapia with 0%, 30% and 60% DDGS, with and without added lysine, and the balance of the protein coming from soy meal. Juvenile Nile tilapia were fed these diets for 12 weeks. Weight gain and feeding efficiency of the diets were not significantly different from the fish consuming the soy protein control diet, except for the diet with 60% DDGS without added lysine, which was lower weight gain and feeding efficiency. Blood cell counts, oxidative burst activity, plasma lysozyme, complement, or globulin protein measurements were not different among fish consuming the diets. A disease challenge of the fish with Streptococcus iniae resulted in an overall mortality of 55%, but the diets did not significantly affect morbidity nor mortality. Specific immune response, measured by ELISA, was higher in the fish consuming 60% DDGS with added lysine, but this did not affect disease resistance. We conclude that DDGS can partially substitute for soy protein in tilapia diets at a ratio of up to 60% with the addition of lysine. Furthermore, the yeast component of DDGS does not appear to have significant impact on immune disease resistance against S. iniae in juvenile Nile tilapia.