Open AccessExogenous xylanase improves growth, protein digestibility and digestive enzymes activities in Nile tilapia, Oreochromis niloticus, fed different ratios of fish meal to sunflower meal
Author(s) -
Hassaan Mohamed S.,
Mohammady Eman Y.,
Soaudy Mohamed R.,
Abdel Rahman Amina A. S.
Publication year - 2019
Publication title -
aquaculture nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.941
H-Index - 79
eISSN - 1365-2095
pISSN - 1353-5773
DOI - 10.1111/anu.12903
Subject(s) - xylanase , nile tilapia , oreochromis , biology , phytase , feed conversion ratio , protein efficiency ratio , fish meal , dry matter , food science , tilapia , meal , zoology , amylase , digestion (alchemy) , weight gain , biochemistry , enzyme , chemistry , body weight , endocrinology , fish <actinopterygii> , fishery , chromatography
A 3 × 2 factorial experiment was designed to evaluate the effect of different ratios of fish meal (FM): sunflower meal (SFM) with or without exogenous xylanase supplementation on growth, feed utilization, digestive enzymes activities, apparent digestibility, intestinal and liver morphology and chemical composition of Nile tilapia, Oreochromis niloticus . Three isonitrogenous (329.80 g/kg of crude protein) and isoenergetic (18.46 MJ/kg gross energy) experimental diets were formulated as SFM 1 (FM:SFM = 2:1), SFM 2 (FM:SFM = 1:1) and SFM 3 (FM:SFM = 1:2) based on protein content. Each diet was supplemented with 0 or 0.5 g/kg of exogenous xylanase and was fed to triplicate groups of twelve fish (with initial weight, 1.31 ± 0.02 g) for 84 days. After 84 days of feeding period, the highest weight gain, specific growth rate, protein efficiency, protein productive value and the best feed conversion ratio were recorded in fish fed either SFM 1 or SFM 2 supplemented with exogenous xylanase. Whereas lowest growth performance was recorded in fish fed SFM 2 and SFM 3 un‐supplemented with xylanase. The highest activities of chymotrypsin, trypsin, lipase, amylase, alkaline phosphatase and cholecystokinin were observed in fish fed SFM 1 and SFM 2 diets supplemented with xylanase. The highest ADCs of dry matter, protein, lipid and digestible energy were recorded in fish fed SFM 1 and SFM 2 diets supplemented with exogenous xylanase. Supplementation of exogenous xylanase improved muscularis mucosa thickness, height of mucosal folds and enterocytes of intestinal fish. Addition of exogenous xylanase increased the calcium and phosphorus retention. Results of this study indicated that the addition of exogenous xylanase to diet containing high inclusion level of sunflower meal improved growth, digestive enzymes, nutrient digestibility, histological morphometric of liver and intestine and nutrient retention.