Effects of diet containing Wood betony, Stachys lavandulifolia extract on growth, gut microbiota and intestinal structure of the African cichlid, Sciaenochromis fryeri

Four isocaloric diets were formulated to contain 0 (control), 2, 4 and 8% of Wood betony (WB), Stachys lavandulifolia hydroalcoholic extract in a 56-days feeding trial on African cichlid, Sciaenochromis fryeri. The regression analysis of growth performance indices indicated that the best performance parameters including specific growth rate and weight gain were obtained in 3.9% WB in the diet. Total bacterial counts in the fish gut were reduced significantly from 20.50±4.22 (×103 Colony-Forming Unit; cfu g-1 ) in the control to 9.30±0.71, 3.60±0.98 and 3.10±0.80 (×103 cfu g-1 ) group of fish fed on 2, 4 and 8% WB, respectively (P<0.05). No significant change was observed in the number of lactic acid bacteria and it was in the range of 0.80-1.30 (×103 cfu g-1 ). Evaluation of the mid-intestine morphology of fish fed on the graded levels of WB was done. Although fold and enterocyte heights were significantly increased in the fish fed on WB-enriched food in comparison to the control, the intestine diameters and microvilli lengths were not affected. This study indicated that hydroethanolic extract of WB can be considered as a supplement in fish diet to improve growth and some physiological aspects of the cichlid.