Crude palm oil as a source of carotenoids and tocopherols to enhance the reproductive potential of Etroplus suratensis, the pearlspot

Abstract

Crude palm oil which is rich in carotenoids and tocopherols (700 and 800 ppm, respectively) was incorporated in pelleted feeds fed to pearlspot Etroplus suratensis reared in brackishwater earthen ponds. The fish were cultured for 11 months (average stocking size 4.30 cm, 1. 70 g) on three supplementary feeds in three separate ponds; a fourth pond in which no feed was given served as the control. Three isoproteinaeceous feeds (about 33% of protein by dry weight) of varying composition were formulated with locally available ingredients: ORT (containing groundnut oilcake, rice bran and tapioca), P-ORT (containing prawn waste, groundnut oilcake, rice bran and tapioca) and oil P-ORT (P-ORT sprayed with a mixture of crude palm oil and fish liver oil in the ratio of 4:1). From observations made on the percentage occurrence of ripe fish, gonadosomatic index, egg volume and histological studies, it could be inferred that oil P-ORT had a positive influence on ovarian development and maturation. However, proximate composition analyses of ovary showed no significant difference between treatments.