Iranian Journal of Fisheries Sciences 11(1) 28-36 2012 Effects of different starter diets on growth indices of Caspian Kutum, Rutilus frisii kutum larvae Falahatkar B.*; Mohammadi H.; Noveirian H. Received: December 2010 Accepted: April 2011 Abstract Six different diets including two rainbow trout starters, Gammarus dry powder, shrimp dry powder, egg yolk dry powder and newly hatched Artemia were used in feeding of Caspian Kutum larvae. During a 4-week trial, larvae with a mean weight of 17.5 ± 4.7 mg were fed with three replicates and growth parameters were measured at the end of the experiment. Thirty fish in each experimental unit with 3 L volume were fed 6 times daily according to their satiation. Results showed that there were significant differences in the final weight, final length, body weight increase, voluntary feed intake and specific growth rate for weight and length among the treatments (P<0.05), but not in the condition factor (P>0.05). The best performance was observed in fish fed Artemia nauplii. The survival rate was significantly different among the treatment (P<0.05) which the highest (75.6 ± 3.8%) and lowest (22.2 ± 11.7%) were observed in fish fed Artemia nauplii and Coppens, respectively. According to obtained results, it appears that except Artemia, the most suitable and inexpensive diet is egg yolk powder, which can results in high growth performance and survival rates. The results of this study suggested that using dry non-live diets with good composition could be replaced with Artemia that had suitable growth and survival rate in Caspian Kutum during larval. Downloaded from jifro.ir at 16:55 +0330 on Thursday September 23rd 2021 Keywords: Live food, practical diet, growth, survival, larvae, Caspian Kutum _____________________ Fisheries Department, Faculty of Natural Resources, University of Gilan, Sowmeh Sara, 1144, Gilan, Iran. *Corresponding author’s email: [email protected] 29 Falahatkar et al., Effects of different starter diets on growth indices of Kutum……. Introduction Caspian Kutum is one of the most High abundance of Caspian Kutum is economically important bony fish of the found particularly in areas where dense southern Caspian Sea (Abdoli, 1999). The mollusca are available (Razavi Sayyad, main distribution of this species belongs to 1984).Each dietary regime or culturing the southern part of the Caspian Sea from technique which is able to reduce the Kura River in the western part to Hossien natural food dependence is considered as Gholi bay and Atrak River in the south- an economical rearing technique east region (Razavi Sayyad, 1984). This (Canavate and Fernandez-Diaz, 1999; fish is locally known as Mahi-Sefid and Akbari et al., 2011). According to studies commonly called as Kutum; it belongs to done on Caspian Kutum nutrition in the the Cyprinids family and has a high earthen ponds, this fish in addition to using commercial value (Abdoli, 1999; Abbasi natural foods and wet diets, is also able to et al., 1999). Several factors such as utilize the formulated diets and showed environmental pollution of the sea and good growth and survival rate (Noveirian rivers, construction of dams, destruction of et al., 2005, 2007, 2008; Haghighi et al., spawning grounds in the rivers, over- 2009). Several researches have been fishing and reduction of natural spawning carried out on Caspian Kutum and its cause decreasing of fish stocks in recent abilities, showing that it is a suitable decades (Razavi Sayyad, 1984; candidate for aquaculture purposes, but for Abdolmaleki, 2006). Hence, there is the achievement of this aim, having the special consideration for Kutum artificial knowledge of the principles of breeding breeding and raising them up to one gram and raising techniques of Kutum is size for stocking rehabilitation. required. Appropriate feed formulation of Limited data are available in Caspian Kutum requirements in the pond biology, nutritional requirements and culture is an essential criterion for rearing Downloaded from jifro.ir at 16:55 +0330 on Thursday September 23rd 2021 necessary techniques for larval rearing in them in captivity and it needs more studies culture systems. The main food source of in this field. One of the most steps for fish Caspian Kutum in the first 2-week age is rearing is feeding larvae and shifting its phytoplankton; from the third week when diet from live foods to formulated diets. the larva reach the size of 15 to 17 mm, Therefore, the purpose of this study was to zooplankton is the main food for Caspian find out the effects of live foods and Kutum. After six weeks, when the larvae formulated diets on growth parameters of metamorphosed to advanced-fry of 2 g Caspian Kutum at larval stage. size, the benthic animals such as Gammarids, small shrimps and other Materials and methods benthic organisms become the main food Eggs source and incubation sources for this species (Razavi Sayyad, In March 2008, ripen and matured fish (4 1984; Efatpanah, 1993). The Kutum main males with average weight 750 g; and 5 food items in the Caspian Sea preferably females with average weight 1200 g) were consist of mollusks and also crustaceans. collected by seine net from Ghaziyan area Iranian Journal of Fisheries Sciences, 11(1), 2012 30 (Anzali, Gilan, Iran) and transferred to temperature was measured 3 times daily at aquaculture facilities at Faculty of Natural 8, 12 and 16 h and the average was 19 ± Resources, University of Guilan in 2ºC. The water was siphoned from the Sowmeh Sara, Guilan, Iran. All fish were bottom of fish container every morning to carefully stocked at a fiberglass tank of 5 remove wastes and fifty percent of the m3 capacity which was filled by 3 m3 of water was changed with fresh and filtered fresh and filtered water. After 3 days, all water. Probable mortalities were recorded fish were spawned at the same tank. and removed from the container every day. Broods were exited from spawning tanks Calculation of growth indices and eggs were incubated at the same place Due to the delicacy and tiny size of larvae and until they were hatched. Eggs were eyed their mortalities all samples were measured after 4 days and all were hatched out to (weight to nearest 0.0l g and total length at 1 larvae after 7 days. The temperature, mm) at the end of 4 weeks. Condition factor (CF), body weight increase (BWI), specific dissolved oxygen and pH of the incubation growth rate for weight (SGR ) and length tank (well-water supply) were 17 ± 1.3ºC, W (SGRL), voluntary feed intake (VFI) and 7.7-8 mg L-1 and 7.7, respectively. survival rate (SR) were calculated according to Larval rearing and adapting with artificial the following formulas (Huang et al., 2003; Ai food et al., 2004; Falahatkar et al., 2009): All larvae in tank were adapted with egg CF=body weight/fork length³ × 100 yolk and liquid soybean as artificial food BWI= (final body weight – initial body for one week; then 540 healthy larvae were weight)/initial body weight × 100 selected and transferred to experimental SGRW= (ln final weight – ln initial containers with 3.5 L capacity which was weight)/days × 100 filled with 3 L of fresh and filtered water. SGRL= (ln final length – ln initial In each container, 30 larvae with an length)/days × 100 average weight of 17.5 mg and 13.8 mm VFI= [(feed consumed/days) × (2/final Downloaded from jifro.ir at 16:55 +0330 on Thursday September 23rd 2021 total length were randomly distributed in biomass + initial biomass)] × 100 18 tanks. All larvae in containers were SR= (number of fish at final/number of held for acclimation 3 days prior to the fish at start) × 100 experiment. During the experiment, Statistical analysis photoperiod was set as 12L: 12D. Homogeneity of data was checked with Experimental design Kolmogorov-Smirnov test. Data were then Six treatments with triplicate groups were analyzed by one-way analysis of variance conducted for six diets including Artemia (ANOVA). When the difference was nauplii as live food; rainbow trout starter observed, Tukey’s test as post hoc was ® ® foods (Coppens and Roshd Daneh ), used for mean comparison of treatments at Gammarus powder, shrimp powder and a level of 5% (P<0.05). All performance yolk egg powder were considered as larval was done using SPSS software (version, diets. Larvae were fed six times daily at 8, 13. Chicago, IL). Data are presented as 10, 12, 14, 16 and 18 h for 4 weeks at mean ± standard deviation (SD). satiation. During the experimental period, 31 Falahatkar et al., Effects of different starter diets on growth indices of Kutum……. Results The growth performance of Caspian has been fed with Artemia nauplii and the Kutum larva fed with different diets for poorest weight belonged to fish fed four weeks are shown in table 1. There are Gammarus powder and Roshd Daneh; but significant differences among treatments there were no significant differences in CF (P<0.05) in most parameters. The highest among treatments (P>0.05). final weight was related to the fish which Table 1: Growth indices of Caspian Kutum larvae fed different starter feeds after 4 weeks of rearing (mean ± SD) Different letters in each column show significant differences at a level of P<0.05. CF (condition factor), BWI (body weight increase), VFI (voluntary feed intake). nd: not determined After four weeks of experiment, the The maximum VFI (59%/day) was found maximum weight and BWI were found in in treatment with a diet of Coppens and the fish fed Artemia nauplii and the minimums minimum was in fish fed egg yolk were observed in the treatment in which (P<0.05).