Effect of skip-feeding and re-feeding regimes on compensatory growth, body composition, feed utilization, feeding cost and survival of monosex tilapia (Oreochromis niloticus) in pond aquaculture system

Abstract

Monosex tilapia has great acceptability particularly among the lower income people due to its lower price. However, due to increased feed price the price of tilapia has been increased in recent years. Compensatory growth (CG) of fish that is achieved after a period of feed deprivation can potentially reduce the feed cost. The present study aimed to get CG in tilapia farming so as to reduce the production cost of this popular fish. Tilapia fry of 0.54 g body weight were nursed in hapa for one month and then stocked in earthen ponds where two different restricted feeding regimes were imposed for next two months followed by one month feeding at satiation level. Sampling was done fortnightly to record average weight gain in control and treatment groups. Average individual weight in restricted feeding group (T1) reached to 170.11±4.6 g in a three months experimental period and it did not significantly (p>0.05) differ with the weight gained in control group (182.79±5.32 g) where fish were fed on regular basis. The specific growth rate (SGR) also showed no significant difference (p>0.05) between T1 (SGR 2.66±0.011 % day-1) and control group (SGR 2.69±0.012 % day-1). Feed Conversion Ratio (FCR) in T1 (1.26) was found significantly (p<0.05) lower to that of control group (1.47), hence the per unit production cost was also found significantly lower in T1 (BDT 75 Kg-1) compared to that of control (BDT 88.23 Kg-1). On the other hand no significant difference was evident in biochemical parameters between the control and restricted feeding groups.  Thus, this study suggests skip feeding as an appropriate tool to achieving CG in monosex tilapia and to trim down the production cost as well.