Influence of salinity on growth increment, feed conversion and body composition of common carp, Cyprinus carpio (Linnaeus, ۱۷۵۸) fingerlings in the captivity

Present study was conduct to observe the effect of salinity levels (۵‰, ۱۰‰, ۱۵‰, ۲۰‰ and ۲۵‰) on growth increment, feed conversion and body composition of Common carp, Cyprinus carpio (mean body weight ۵±۰.۰۱ g) were examined. Fingerlings were randomly distributed into the glass tanks (۶۰×۳۰×۴۵ cm each). ۱۰ fish per tank with two replications. Fish were fed with floating pelleted feed having ۳۵% protein with ۳% body day-۱ for ۶۰ days. Results shows that the growth increment reared on ۵‰ - ۱۵‰ salinity were significantly highest in term of weight gain, WG % of initial weight, daily weight gain, specific growth rate, condition factor and survival rate than those reared on ۲۰‰ and ۲۵‰ salinity, feed conversion ratio were found similar in all levels which is not significantly different (p>۰.۰۵) in all levels. Whole body composition i.e. crude protein (۱۴.۶۲ –۱۵.۴۸), moisture (۷۷.۱۱ –۷۷.۸۱), crude fat (۳.۵۲–۳.۶۱), ash (۳.۶۶–۳.۷۱) contents of fish whole body were not significantly (p>۰.۰۵) different in various salinity levels. Mean values of water quality were found acceptable for common carp i.e. temperature ۲۸.۰۸± ۰.۱۳°C, dissolved oxygen ۷.۴± ۰.۰۷ mg L-۱, pH ۷.۷±۰.۰۱ and ammonia ۰.۰۲۳±۰.۰۰۴ mg L-۱. Relationship between Log body weight and log total length of the present study shows that fingerlings reared on ۵‰ -۱۵‰ was significantly (p<۰.۰۵) higher than ۲۰‰ and ۲۵‰ salinity levels. Histology of gills shows normal appearance of gill filaments and gill lamellae up to ۱۵‰ salinity. Present results prove that Common carp can be reared up to ۱۵ ‰ salinity to get good growth and higher survival rate.

کلیدواژه ها:

Common carp ، Cyprinus carpio ، Growth ، Feed conversion ، Salinity