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

Abstract

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 (×10 3 Colony-Forming Unit; cfu g -1 ) in the control to 9.30±0.71, 3.60±0.98 and 3.10±0.80 (×10 3 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 (×10 3 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.