Research Information System
1st World Conference on Innovative Animal Nutrition and Feeding (WIANF), Budapeşte, Hungary, 15 - 17 October 2015, pp.106-107, (Full Text)
INTRODUCTION
Fish meal is the main dietary protein source in fish feed formulation, yet it is a limited resource and is expensive. Alternative protein sources can reduce the cost of fish feeds. Distillers dried grains with solubles (DDGS), a major by-product of the dry mill ethanol industry, is currently readily available and competitively priced relative to other conventional alternative protein sources1. Thus, the aim of the study was to evaluate the effects of corn distillers dried grains with solubles (DDGS) used as an alternative protein source on skin and fillet colouration of rainbow trout (Oncorhynchus mykiss).
MATERIALS AND METHODS
Four isoproteic (45.47% CP) and isocaloric (17.42 MJ DE/kg) diets were formulated using DDGS (0, 10, 20 and 30%) for a feeding trail of 84 days. Fish (Initial weight: 19.88 g) were distributed into triplicate treatments at a rate of 25 fish per 200-L tank and fed to satiation with one of the experimental diets for three times a day. Colour measurements were recorded at the end of the feeding trial (Final fish weight: 104.13 ± 10.98 g) in below of dorsal fin of five fish from each tank using a Konica Minolta Chroma Meter CR400. Triplicate measurements were taken at each site, to give a mean value for each area. Data were expressed using the L* a* b* system, representing lightness, redness and yellowness2. A standard white tile with reflectance values of L* = 95.23, a = -0.31 and b = +3.01 was used as the reference.
RESULTS AND DISCUSSION
Data on the skin and fillet colour of the experimental fish are given in Table 1. There was no significant difference in the skin redness (a*), yellowness (b*), brightness (C*, chroma) and hue (h*, in radians) among groups (P>0.05). The only difference was the higher value of lightness (L*) in control group. Skin L* of the 10% DDGS groups was significantly lower than that of the control group (P<0.05). Similarly, skin colour presented higher levels of L* in sea bream fed diet fish meal3. Fillet b* and C* parameters significantly affected by the dietary treatments while L*, a* and h* colour parameters was unaffected (Table 1).
CONCLUSIONS
The results of the present study showed that the colours of rainbow trout skin and fillets were not negatively affected by dietary treatments. The coloration of fish was not modified negatively by the use of DDGS in diets.
REFERENCES
ACKNOWLEDGMENTS
This study was financially supported by the Scientific Research Projects Coordination Unit of Akdeniz University