Open AccessComparison of Purified and Practical Diets Supplemented with or without β‐Glucan and Selenium on Resistance of Hybrid Striped Bass Morone chrysops ♀× M. saxatilis ♂ to Streptococcus iniae Infection
Author(s) -
Jaramillo Francisco,
Gatlin DelbertM.
Publication year - 2004
Publication title -
journal of the world aquaculture society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.655
H-Index - 60
eISSN - 1749-7345
pISSN - 0893-8849
DOI - 10.1111/j.1749-7345.2004.tb01081.x
Subject(s) - streptococcus iniae , biology , selenium , morone , zoology , menhaden , fish meal , bass (fish) , morone saxatilis , food science , dicentrarchus , fishery , fish <actinopterygii> , materials science , metallurgy
This study was conducted to evaluate the efficacy of β‐glucan and selenium supplements to the diet on increasing survival of hybrid striped bass Morone chrysops X M. saxatilis exposed to Streptococcus iniae. A 2 × 2 × 2 factorial design was employed by including purified casein/gelatin‐based diets and practical menhaden fish meal‐based diets with supplement! of either β‐glucan from barley at 0 and 0.1 % of diet or sodium selenite at 0 or 0.2 mg/kg diet or a combination of these supplements. All diets were formulated to meet the nutritional needs of hybrid striped bass with the exception of selenium. The purified and practical basal diets contained 0.03 and 1.03 mg Se/kg, respectively, and the diets supplemented with sodium selenite had an additional 0.07 mg Se/kg on average. Juvenile hybrid striped bass initially averaging 2.44 ± 0.17 g/fish were fed the eight experimental diets in triplicate 110‐L recirculating aquaria for 6 wk, after which they were immersed in a bath of S . iniae at 6.2 × 10 6 CFU/mL for 2 h and monitored for 21 d. Weighi gain and feed efficiency were significantly ( P < 0.05) affected by diet type and selenium supplementation, with fish fed practical diets and those supplemented with selenium having the greatest values. Supplementation of β‐glucan to the purified or practical type diets did not significantly affect survival of fish after experimental infection. The most notable difference ( P < 0.0001) was in the comparison of diet type; the survival rate of fish fed the practical diets was 75% compared to 35% for those fed the purified diets. Dietary supplementation of β‐glucan did not enhance disease resistance in the present study. Fish fed menhaden fish meal‐based diets were significantly more resistant to 5. iniae in comparison to the those fed the purified diets. Thus, nutritional influences on disease resistance of hybrid striped bass were evident in this study and warrant further investigation.