The effect of black glutinous rice bran (Oryza sativa L.) in diets of Nile tilapia (Oreochromis niloticus)

The effect of black glutinous rice bran inclusion used in diets of Nile tilapia was  studied in fish with an initial weight of ۸.۷۶±۰.۱۷g per fish and fed with experimental diets supplemented with black glutinous rice bran at ۰ (control), ۵۰, ۱۰۰, ۱۵۰ and ۲۰۰ g kg-۱ for ۶۰ days. The results of phytochemical analyses of black rice bran showed that the total anthocyanin, phenolic, tannin and phytic acid contents were ۵۲.۴۲±۰.۲۳, ۳.۷۷±۰.۰۳, ۰.۳۲±۰.۱۳, ۰.۱۴±۰.۰۱ mg/۱۰۰g, respectively. The properties of black glutinous rice bran acted as an antioxidant, and the inhibitory percentage of ۱,۱-diphenyl-۲-picrylhydrazyl (DPPH) and thiobarbituric acid reactive substances (TBARs) was significantly different (p<۰.۰۵) on storage in different conditions of ۴ and ۲۵ ºC. Black glutinous rice bran stored at ۴ °C showed significantly higher antioxidant activities analyzed by DPPH and TBARs tests (p<۰.۰۵). The percentage of digestibility coefficients and protein digestibility in test diets ranged from ۷۵.۲۱-۸۱.۹۵ and ۸۷.۳۷-۹۱.۸۷ (p>۰.۰۵), respectively. The highest average daily gain, specific growth rate and protein efficiency ratio were observed in fish fed with the diet containing  ۱۵۰ and ۲۰۰ g kg-۱ black rice bran (p<۰.۰۵). Feed conversion ratio was slightly better in fish fed the diet supplemented with ۲۰۰ g kg-۱ black glutinous rice bran. The serum biochemical values including total protein, albumin, total bilirubin, alkaline phosphatase (ALP), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity were not significantly different in the various experimental groups (p>۰.۰۵). Therefore, supplementation of black glutinous rice bran in tilapia diets at a rate of ۲۰۰ g kg-۱ resulted in better growth and had no adverse effects on digestibility and serum biochemistry.  

کلیدواژه ها:

Black glutinous ، Tilapia ، Phytochemical ، Antioxidant ، Growth ، Serum biochemistry