Effect of Dietary Dried Distiller's Grains with Solubles (DDGS) on the Growth, Body Composition, and Immune Enzymes Activities of Sea Cucumber (Apostichopus japonicus)

Abstract:

Dried distiller's grains with solubles (DDGS) is the primary corn co-product of dry-grind fuel ethanol plants. It consists of distiller's grains combined with condensed solubles from yeast fermentation, and typically contains about 27% crude proteins, 7% starch, 42% neutral detergent fibers, and 0.6% phosphorus. DDGS has gained increasing interest as a potential feed ingredient for aquaculture animals due to the low cost and enrichment in proteins, vitamins, and minerals. This research was carried out to investigate the effects of DDGS level on the growth performance, body composition, and immune enzyme activities of sea cucumber Apostichopus japonicas. Five isonitrogenous and isocaloric diets were formulated that contained 0, 10%, 20%, 30%, and 40% DDGS, designated as DDGS0 (control), DDGS10, DDGS20, DDGS30, and DDGS40 groups respectively. Three replicates of sea cucumber weighing (9.69±0.28) g were fed in one dietary group till apparent satiety two times every day for 56 days. The weight gain (WG) and the specific growth rate (SGR) were decreased along with the increase in DDGS level but there was no significant difference between experimental groups (P>0.05). The body wall index (BI), the intestine index (II), the intestine length ratio (ILR), and the composition of body wall were not affected by the addition of dietary DDGS (P>0.05). The activities of lysozyme (LZM) and acid phosphatase (ACP) in coelomic fluid were higher in the DDGS20 and DDGS40 groups than in the control group (P<0.05). The activities of phenol oxidase (PO) in coelomic fluid were raised along with the increase in the level of DDGS, and were significantly higher than that of the DDGS0 group (P<0.05). The activity of alkaline phosphatase (AKP) was not affected by dietary DDGS (P>0.05). These results indicated that corn DDGS could be a potential dietary ingredient and could be used at a concentration of 20% to 40% to improve the growth and immunity of sea cucumbers.