Effect of seaweeds supplemented diets on growth performances of koi carp (Cyprinus carpio Linnaeus, 1758) fry in laboratory conditions

Abstract

There is a growing trend to use seaweeds as a supplement in fish feed due to its nutritional value, low cost and the availability. The objective of the present study was to determine the effect of two types of seaweed (Ulva lactuca and Sargassum cinereum) supplemented diets on growth performance of koi carps at their fry stage (birth up to three months). The experimental set up consisted of three treatments with supplemented diets as U. lactuca (T1), S. cinereum (T2) and the Control. Control diet consisted of fishmeal and soya bean (41.57% each), Coconut meal and wheat flour (7.78% each) and vitamin and mineral mixture (1.3%). Crude protein content (CP) of control diet was 36.26±0.57%. Thirty percent of the weight of control diet was replaced by the Ulva and Sargassum powder to prepare test diets T1 and T2 and the estimated CP of the diets were 24.14±0.27% and 21.33±0.01% respectively. Fourteen-week indoor experiment was carried out using koi carp fry belonging to the same cohort having mean weight and mean length 2.20±0.08g and 3.89±0.04cm respectively. They were introduced into 150L fiber tanks (n=20 per tank; four replicates per treatment) prepared under 3 treatments; C, T1 and T2. The fish were fed 5% of their body weight twice a day (09.00h and 15.00h) for 98 days. The weight measurements were measured once in two weeks. The water quality parameters, i.e., Temperature, pH, Conductivity, Dissolved oxygen, Nitrate and Phosphate concentrations in treatment tanks were measured twice a week during the experiment. Weight Gain (WG), Daily Growth Rate (DGR%), Relative Growth Rate (RGR%), Feed Conversion Ratio (FCR), Feed Conversion Efficiency (FCE%), Specific Growth Rate (SGR) were calculated to evaluate the fish performance due to the consumption of prepared diets and analysis of growth parameters were statistically tested (one-way ANOVA and Tukey test for pair-wise comparisons). At the end of the 14th week of the experiment, mean weight, mean weight gain, daily growth rate values showed significant difference (P< 0.05). Tukey test revealed that FCR of T2 and T1 were significantly different (P<0.05) from C, while FCE% of T2 was significantly different (P<0.05) from C. Out of the two seaweed supplemented diets Sargassum supplemented diet has shown better growth performance in koi carp. Water quality parameters did not show significant difference (P>0.05) among treatments. The results showed the potential use of seaweed; U. lactuca and S. cinereum as a dietary supplement for koi carp at fry stage to obtain better growth performance by developing low-cost diet.