Digestibility of Local Feed Ingredients in Tilapia Oreochromis niloticus Juveniles, Determined on Faeces Collected by Siphoning or Stripping

Abstract

Eight locally available protein source ingredients in Tanzania were selected for assessment of apparent digestibility (AD) in tilapia Oreochromis niloticus, using faeces samples collected by siphoning or stripping. The selected protein source ingredients were Lake Victoria sardines (FM), brewers spent yeast (BSY), moringa leaves (ML), freshwater shrimp (FSH), marine shrimp (MSH), cattle blood (CB), duckweed (DW) and fish frames (FF). The AD (%) of dry matter (DM), organic matter (OM) and crude protein (CP) was unaffected (p > 0.782–0.901) by the faeces collection method (i.e., siphoning or stripping), with correlation coefficient (r) of 0.98, 0.99 and 0.93 between AD values for DM, OM and CP, respectively, following siphoning and stripping. The AD (%) of DM, OM, CP and gross energy (GE) in the test ingredients differed (p < 0.0001). The AD (%) of DM and OM was lowest in BSY and DW, followed in increasing order by ML, MSH, FF, FSH and CB. In general, the AD (%) of CP was high (>76%), but with a low value (46%) for DW. The AD (%) of GE was closely correlated (r = 0.96) with the AD of OM. In conclusion, FSH, MSH, CB, FF, BSY and ML have acceptable protein digestibility to be used in tilapia diet formulation.