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ARS Home » Southeast Area » Auburn, Alabama » Aquatic Animal Health Research » Research » Publications at this Location » Publication #267232
Title: Growth response and resistance to Streptococcus iniae of Nile tilapia, Oreochromis niloticus, fed diets containing different levels of wheat distiller dried grains with solubles with or without lysine supplementation

Author
item LI, ERCHAO - Beijing Normal University
item Lim, Chhorn
item CAI, CHUNFANG - Beijing Normal University
item Klesius, Phillip

Submitted to: Animal Feed Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/2/2011
Publication Date: 12/1/2011
Citation: Li, E., Lim, C.E., Cai, C., Klesius, P.H. 2011. Growth response and resistance to Streptococcus iniae of Nile tilapia, Oreochromis niloticus, fed diets containing different levels of wheat distiller dried grains with solubles with or without lysine supplementation. Animal Feed Science And Technology. 170:246-255.

Interpretive Summary: Distiller’s dried grains with solubles (DDGS) are the main by-product of the ethanol production that is produced after fermentation of dry-milled grains to ethanol. As a result of the interest in increasing ethanol production for fuels to reduce the greenhouse gasses, and shortage and dependency on petroleum-based fuel, the U.S. production of DDGS has increased sharply from 16.4 million metric tons (Mt) in 2007 to 35.3 Mt in 2010. Several studies have shown that DDGS derived from corn is a promising protein source and on a protein cost basis, is less expensive than soybean meal (SBM) which is commonly used in aquaculture diets. In addition to corn, other cereal grains, such as wheat, have also been used to produce ethanol. Wheat DDGS differs markedly in nutrient composition from corn DDGS, but no information is available on its nutritional value or use in fish diets. Thus, this study was conducted to evaluate the influence of dietary levels of wheat DDGS on growth performance, immune responses, and resistance of Nile tilapia to Streptococcus iniae challenge. Results of the current show that 30% wheat DDGS can be included in tilapia diets as a replacement of a SBM and corn meal (CM) without requiring the addition of lysine. Increasing wheat DDGS level to 40% without adding lysine significantly decreased weight gain (WG), feed efficiency ratio (FER), protein efficiency ratio (PER) and whole body moisture content, but significantly increased whole body lipid compared with fish fed diets with lower levels of DDGS. However, supplementation of lysine to the 40% wheat DDGS diet significantly increased WG, FER, PER and whole body moisture as well as decreased body lipid. Hematological and immunological parameters, the average number of days to first mortality after S. iniae challenge and cumulative mortality 4 weeks post challenge were not affected by dietary treatments. In conclusion, wheat DDGS can be incorporated in Nile tilapia diets at a level of 30% as a substitute, on an equal protein basis, for a combination of SBM and CM without requiring lysine supplementation. The inclusion level of wheat DDGS can be increased to at least 40% if lysine was supplemented to a level equal to that of the control diet. The information obtained from this study will allow flexibility in least-cost feed formulation leading to decreased feed costs, increased profits for fish producers, as well as increase the market demand of DDGS.

Technical Abstract: A study was conducted to evaluate the effect of dietary levels of wheat distiller’s dried grains with solubles (DDGS) with or without lysine supplementation on growth, body composition, hematology, immune response, and resistance of Nile tilapia, Oreochromis niloticus, to Streptococcus iniae challenge. Nine isocaloric diets containing 0 (control), 10, 20, 30 and 40% DDGS without (Diet 2-5) and with (Diet 6-9) lysine supplementation to obtain lysine level equal to that of the control diet as partial replacement of a combination of soybean meal (SBM) and corn meal (CM) on an equal protein basis were fed to juvenile Nile tilapia (3.92±0.07 g) for 10 weeks. Fish fed Diet 5 had significantly lower weight gain (WG), feed efficiency ratio (FER), protein efficiency ratio (PER) and whole body moisture content, but had significantly higher whole body lipid compared with those fed the control diet (Diet 1). Supplementation of lysine to the 40% wheat DDGS diet (Diet 9) significantly increased WG, FER, PER and whole body moisture as well as decreased body lipid to levels similar to those fed Diet 1. Whole body ash tended to increase with increasing levels of dietary wheat DDGS but the differences were not always significant. Hematological and immunological parameters, the average number of days to first mortality after S.iniae challenge and cumulative mortality 4 weeks post challenge were not affected by dietary treatment. Results of this study suggest that wheat DDGS can be incorporated in Nile tilapia diets at a level of 30% as a substitute, on an equal protein basis, for a combination of SBM and CM without requiring lysine supplementation. The inclusion level of wheat DDGS can be increased to at least 40% (highest level evaluated) if lysine was supplemented to a level equal to that of the control diet.