The effect of feeding frequency on water quality and growth of the black tiger shrimp ( Penaeus monodon)

Abstract

The feeding strategy used in the commercial culture of shrimp can have a significant impact on pond water quality and hence growth, health and survival of the shrimp, as well as the efficiency of feed utilization. These factors contribute to the profitability of production and to the environmental impact of shrimp farming. The effect of four different feeding frequencies (3, 4, 5 and 6 feedings day −1) on the growth and survival of the black tiger shrimp, Penaeus monodon, and water quality was studied in an 8-week growth trial. The shrimp were held in 20×2500-l outdoor tanks containing water and sediment from a shrimp pond. The water management and aeration strategies were designed to simulate a shrimp pond system. The shrimp (initial weight of 5.6 g) were stocked at a density of 25 animals m −2 and fed a widely used, commercial pelleted feed, with all the feed being placed on feeding trays. The uneaten feed on the feeding trays was removed at specific time intervals so that in all treatments, the shrimp had access to the feed for 12 h day −1. There were no significant ( P>0.05) differences due to feeding frequency on growth rate (1.4±0.08 g week −1), feed conversion ratio (FCR) (2.0±0.27) or survival (84±7.6%) of shrimp. Similarly, the water quality parameters (total N, ammonium, nitrate/nitrite, dissolved organic nitrogen, total phosphorus, phosphate, chlorophyll a, oxygen, pH, temperature, salinity, turbidity) were not different among treatments. The results suggest that there is no benefit from feeding P. monodon more frequently than 3 times day −1 when using a feed that is nutritionally adequate and has high water stability. Therefore, it may be possible to reduce feeding frequency in commercial shrimp ponds without adversely affecting water quality, shrimp growth rate and survival, thereby improving farm profitability.