Prebiotics like probiotics are used in aquaculture to maintain the health of a species, however prebiotics unlike probiotics are a non-digestible food ingredient which can benefit the host by stimulating the growth and activity of bacteria residing in the colon, promoting a healthier host organism. This study investigates the effects of prebiotics on nutrient digestibility of a soybean-meal-based diet by the Red Drum Sciaenops ocellatus (Linnaeus).
The authors used a recirculation system for the 35 sub adult Red Drum which were fed a control diet containing 40% crude protein, exclusively from menhaden fish meal, 0% lipid, and an estimated available energyof14.6 kJ g-1. Five experimental diets were to be similar to the control diet, but with approximately 50% of the protein supplied by menhaden fish meal and 50% provided by soybean meal. To four of the experimental diets, prebiotics were singularly added at 1% of dry weight in place of cellulose while the basal diet had no prebiotic supplementation. The prebiotics in use for the trial (a mix or individually) were mannanoligosaccharide (MOS), galactooligosaccharide (GOS) and inulin. The faecal matter was used for nutrient analysis.
The results showed that the basal diet mixed with MOS and GOS significantly increased protein (82% for the three tanks) and organic matter (69, 64 & 66% for the three tanks) in comparison to the control diet which showed 69% for protein and 49% for organic matter. However the lipid values were significantly decreased for fish fed with MOS, GOS and inulin (63, 61 & 61%) compared to the control of 77%. Energy values were the same for the fish fed with inulin as the control diet of 54%.
This is the first study to demonstrate that nutrient and energy digestibility of soybean-meal-based diets can be enhanced by prebiotics. The wider significance of this investigation is paramount to replacing a higher percentage of fishmeal in fish diets with soybean and or other protein replacements. The side effects such as gastroenteritis can be treated with probiotics and the protein enhancement can be treated with prebiotics, thus a mixture of both in diets would be the next step in further research.
A review of: Burr, G., Hume, M., Neill, W. H., & Gatlin III, D. M. (2008). Effects of prebiotics on nutrient digestibility of a soybean-meal-based diet by red drum Sciaenops ocellatus (Linnaeus). Aquaculture Research, 39, 1680-1686.
1 comment:
Hey Dan,
Interesting review. I've never heard of a Red drum fish before but they are apparently a popular gaming fish. Presumably a good eating fish as well as it is apparently farmed all over the world.
Regarding the 3 poly/oligosaccharides they used in the study; were they included in the feed as food for gut microbiota or was it for the fish itself? I read that inulin promotes the growth of intestinal bacteria and enhances absorption of trace metals so I am assuming they were included in the feed for the microorganisms. The structure of inulin (beta 1-2 glycosidic link) is quite different from the typical 1-4 /1-6 alpha and beta glycosidic linkages commonly seen in plant polysaccharides such as amylose, cellulose and amylopectin. I wonder if we have enzymes that can break this product down or whether is is something that only gut bacteria can digest.
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