The effects of different grain sources on gut evacuation rate and nutrient digestibility in common carp, Cyprinus carpio
2018
Zahra Mazahery Tehrany | Abdalsamad Keramat Amirkolaie | Hossein Oraji
The main objective of this study was to investigate whether dietary cereal grains of different carbohydrate sources can change nutrient digestibility, evacuation rate and the number of bacterial colony in gut. Common carp with an average weight of 244.7±6.3 g were divided randomly into sixteen 500-L tanks with a stocking density of 18 fish per tank. Four experimental diets were formulated by inclusion of four cereal grains (wheat meal, barley meal, corn meal and rice meal) in a basal diet in a ratio of 40%. The four experimental treatments with four replicates were assigned in 16 tanks. Inclusion of different types of cereal grain affected growth related parameters in C. carpio. Corn and wheat diets led to larger weight gains and better feed conversion ratios compared to barley diet (324 and 321 versus 305 g for final weight; 1.93 and 1.90 versus 2.25 for fed conversion ratio). Protein and dry matter digestibility in the common carp fed rice diet were lower in comparison to other cereal grains (73 and 58 versus 79-82 and 67-70%). The maximum and minimum bacterial colony numbers (133 and 63 cfu.gr-1×10-7) were observed in fish fed wheat and corn diets, respectively. Evacuation time showed a delay by feeding on barley diet and almost all dry matter left in part I of the intestine after 30 min (first sampling), but this rate was recorded 70% for corn diet .In conclusion, although dietary grains change evacuation time and bacterial colonial number in common carp, this condition does not have a great impact on nutrient digestibility.
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