عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Occurrence of skeletal disorders, one of the common difficulties in fish larvae, are related to a poorly understanding of the relationship between environmental, genetic and nutritional parameters. X-ray analysis is an effective technique to characterize early stages of skeletal deformities in fish larvae and radiological examination of their vertebral column can provide plentiful information regarding bone composition as well as skeletal abnormalities. Hence, this investigation was aimed to study the skeletal deformity of Caspian roach (Rutilus caspicus) larvae radiological method in response to different dietary P levels during early developmental stage. For this purpose, six semi-purified diets, including A, B, C, D and E supplemented with 0.0, 0.4, 0.8, 1.2 and 1.6% available P were formulated and fed as five percent of body weight of larvae three times a day for 60-day experimental period. At the end of experiment, Standard Length (SL), Head Length (HL), skull index and number of vertebrae were measured on the X- ray pictures. The results showed no significant difference among treatments in terms of measured morphological indices. X-ray analysis showed skeletal disorders, including kyphosis, twisted haemal and neural arches, and irregular vertebrate column in treatments. The skeletal abnormalities had highest incidence in treatments with a low P. Kyphosis placement of the vertebrae was the most frequent abnormality.