افشین امیری سندسی

This study was carried out to evaluate the effect of floating and sinking pellets on growth performance of common carp (Cyprinus carpio). Triplicate groups of 624 carp (average  initial weight 175 g) were stocked in 6 round concrete pond with a density 1/8 kg/m3 and fed to apparent satiation, 4 times a day with interval of 4 h for 75 days. The growth rate of fish was estimated by feeding the extruded and pellet feeds 122.63 and 77.43g respectively. Fish were fed from two type of feed in this culture system had a high survival rate (97-99.5%). Thus, high survival rate of carp in concrete ponds indicate its easy adaptation to new cultural conditions. The results showed that growth and nutrition parametrs included in:weight gain (WG%), specific growth rate (SGR), protein efficiency ratio (PER) increased and food conversion ratio (FCR) decreased significantly when they were fed on floating pellets compared with the fish fed on sinking pellets (p<0/05). Thus, the results showed that carp, despite the oral form and feeding habits of the bed, can easily feed on the floating pellets and have better growth performance.

Phytobiotics are plant derivatives derived from leaves, roots, tubers or fruit plants, solid, dry or essential oils to improve nutrition for livestock and poultry farming. These plant derivatives are well-practiced in aquaculture, such as: stimulating food intake, increasing growth, increasing digestive tract discharges, increasing immunity, anti-coccidiosis and parasitic activity. Existing materials are from bioactive chemical groups such as alkaloids, phenols, flavonoids, terpenes and polysaccharides. Various methods are used to extract these effective ingredients. The choice of these methods in terms of plant species, solvent type, use or non-use of heat requires different techniques. In this paper, while reviewing the use of phytobiotics in aquaculture, the introduction of classical and modern techniques in this regard has been considered. Reports indicate that methods Modern due to the reduction of organic and synthetic chemicals and, saving time, efficiency and better quality of the extractive material are of interest to researchers. And given the need to take advantage of these valuable biomass in aquaculture, familiarity with these techniques in the future will be the key to achieving sustainable aquaculture.