Dietary Requirement of Vitamin A and Biochemical Composition of Common Carp Cyprinus carpio var. communis

MATERIALS AND METHODS

Materials: For the present study Cyprinus carpio var. communis fingerlings (1.48±0.26 g) were collected from Pandian fish farm near Dindigul, Tamil Nadu, India and transported to the laboratory in polythene bags filled with oxygenated water in the year of March 2007. Fishes were acclimated in plastic round troughs (60 cm dia.) for 15 days at 28±2°C. During acclimation, fishes were fed with trainee feed containing fish meal, ground nut oil cake, wheat flour and rice bran in the form of dry pellets. The raw materials used in this study are fish meal, ground nut oil cake, wheat flour, tapioca powder, sunflower oil, NaCl, supple-vite mix and sodium benzoate. To increase the growth and disease resistance vitamin A added to different concentrations.

Methods: Different ingredients used in the feed preparation were tested for its protein content by Lowry et al. (1951). After knowing their protein contents, feeds were prepared according to square method (Ali, 1980) with varying concentrations of vitamin A such as 0, 100, 200, 300, 400 mg for control, experimental feeds 1, 2, 3 and 4, respectively (Table 1). The components used for feed preparation were dried, powdered and sieved through 425 micron sieve. The ingredients were weighed and mixed thoroughly with 130-150 mL of distilled water.

Table 1:	Ingredients used in the control and experimental feeds (No. 1, 2, 3 and 4) (wt in gm)

The mixed stuff was put in autoclave for 15 min. at 100°C. Then it was extruded with the help of pelletizer. The pellets were dried in room temperature. These pellets were tested for its stability by placing it in the water for 1 h. Uniform size of Cyprinus carpio var. communis fingerlings was selected. The length and weight of fishes were taken. Then the fishes were introduced in the rectangular through (45 cm Lx30 cm Bx15 cm H). Then water in the trough was maintained as 10 liters. Each trough 10 fingerlings were distributed and triplicates were maintained. During rearing the fishes were fed on ad-libitum feed on prepared feed twice a day for 1 h. each from 8-9 am and 4-5 pm. The unfed was dried to constant weight. The faecal matter was collected daily before changing the water with least disturbance to the fishes and dried at 90°C. Approximately 75% of water in the through was replaced with tap water. The experiment was continued for 30 days and on the final day the fishes were weighed in live condition. At the end of the experiment, all of the Cyprinus carpio were chill-killed and stored frozen at-20°C for subsequent determination of whole body composition. Earlier samples of Cyprinus carpio from the initial population were collected and stored frozen for a similar evaluation. The condition factor (K) was calculated (Weatherly et al., 1987) for individual fish before and after the experiments.

Biochemical composition: A known quantity of sample was taken and the excess moisture was removed using a filter paper (Rajendran, 1973). Then the sample was dried in a hot air oven at a constant temperature of 60°C until the wet sample was dried completely. The dried samples were used for estimation of protein (Lowry et al., 1951), carbohydrate (Dubois et al., 1956), lipid (Folch et al., 1957) and the ash content was determined by burning oven-dried sample in a muffle furnace at 550°C (AOAC, 1995).

Statistical analysis: The feed utilization parameters were calculated Statistical analysis Dietary treatments were compared by one way ANOVA all the above mentioned statistical analysis were performed using SPSS statistical software (Ver. 11.5 for Windows, SPSS, Chicago, IL., USA.). Limits of significance for all critical ranges were set at p<0.05.

RESULTS AND DISCUSSION

Condition factor (K) was estimated only for comparative purposes to assess the feed. The condition factor increased in all the fishes after rearing for a period of 30 days in different level of vit. A. The condition factor was best in feed III (2.60±0.015) containing 300 mg vitamin A when compared to other feeds (Fig. 1).

Fig. 1:	Condition factor (K) of common crap

Similar increase in condition factor was reported by Karpagam (2000) when ornamental fish Xiphophorous helleri reared in different concentration of vit C.

The feed utilization parameters were presented in Table 2. Parameters like Feed consumption, protein consumption, feed conversion ratio and feed conversion efficiency were significant (p<0.05) among the dietary treatments. Feed consumption of Cyprinus carpio was higher in feed IV containing 400 mg. In feed IV the feed consumption was increased when the level of vit. A in the feed was increased. Protein consumption of Cyprinus carpio reared in different concentrations of vit. A feeds were significantly increased from 100 to 400 mg. In the present study the maximum protein consumption, feed conversion ratio and feed conversion efficiency was higher in 400 mg of vit. A. Similar study was reported when common carp Cyprinus carpio was fed with 400 mg of vitamin E (Ramachandran et al., 2009). Protein consumption and protein efficiency ratio was higher when the vitamin level in the feed was 100 to 400 mg. Growth percentage growth and relative growth rate was increased in feed IV containing 400 mg vit. A. Similar result was reported when red sward tail and common carp was fed with vitamin C and E in the feed (Karpagam, 2000; Vinothini, 1999; Ramachandran et al., 2009). In the present study both assimilation and metabolism was higher when the level of vitamin A was increased. The gross growth efficiency was higher in feed II containing lower quantity of vit A (200 mg) when compared to other feeds. The gross growth efficiency was significantly varied in different feeds. The net growth efficiency was higher in feed I containing minor quantity of vit A (100 mg).

Table 2:	Feed utilization parameters of common carp (Cyprinus carpio var communis) in relation to different feed (different Vitamin A concentrations)
Each value is the average (±SD) performance of 10 individuals in triplicate observed for 30 days. Value in the same row sharing different superscript are significantly different

Table 3:	Biochemical composition of fish at beginning and end of the experiment (% dry matter basis)
*Wet matter basis. Means of triplicates in the same row sharing different superscripts are significantly different (p<0.05).

The effects of various levels of vitamin A on the body composition of fish differed. Thompson et al. (1995) reported that the dietary vitamin A level did not influence the body composition of rainbow trout. Mohamed et al. (2003) indicated a significant decrease in body fat along with the increase in the dietary vitamin A level however, Abbass (2007) declared that lipids level increased in Cyprinus carpio with the increase of oil sources level in the diet similarly El-Marakby (2006) also confirmed total lipids increased in Oreochromis niloticus with the increase in dietary lipid. Furthermore, Hu et al. (2006) reported that dietary vitamin A had some influence on the body moisture and protein of hybrid tilapia. In the present study, supplemental dietary vit A affect moisture, carbohydrate and ash contents of whole body among groups moisture, carbohydrate and ash contents gradually decrease when concentration of vit A increase (Table 3). Biochemical constituents like protein, lipid and carbohydrates varied significantly (p<0.05).

Several authors also reported that dietary vit. A did not affect the moisture, carbohydrate and ash contents when increasing concentration. This phenomenon has been reported in Brook trout Salvelinus fontinalis (Poston, 1971), guppy (Shim and Tan, 1990), greasy grouper (Mohamed et al., 2003) and Japanese flounder (Hernandez et al., 2005). In the present study Crude protein and lipid content was significantly increased from 100 to 400 mg of vit. A. Interestingly higher protein and lipid content was observed in fish fed with 400 mg of vit. A than other feeds.

CONCLUSION

Present study has clearly indicated fingerlings species of Cyprinus carpio var. communis have different growth performance and different feed utilization efficiency under the different concentration of vit. A examined in this study. Optimum dietary vit A level was necessary for higher net growth efficiency of the fish and approximately 400 mg vit A are needed for the feed consumption, fast growth, protein and lipid content of Common carp. This new information on quantitative dietary vit. A requirement of Cyprinus carpio var. communis is useful in designing practical cost-effective diets for the intensive culture of this species.