NUTRIENT CONTENT AND APPARENT PROTEIN AND LIPID DIGESTIBILITY COEFFICIENTS OF VARIOUS LOCAL FEED INGREDIENTS FOR RABBITFISH, Siganus sp

Digestibility coefficient of feed ingredients is an essential information in screening their potential nutritive values and to enable the formulation of diets that maximize the fish growth by providing appropriate amounts of available nutrients and to limit fish waste product. The aim of this study was to determine the nutrient content of several local feed ingredients and their apparent protein (APDC) and lipid (ALDC) digestibility coefficients for rabbitfish, Siganus sp

Three subset experiments were carried-out sequentially to enable  the apparent digestibility of the four individual feed ingredients to be determined each time (totally twelve ingredients). Each experiment comprised five diets, one reference and four test ingredient diets. Initial body weight (IBW) of S javus used in subset exp 1 and 2 was in a range of 130-150 g while IBW of S guttatus used in subset exp 3 was around 144 g. Fish were stocked into a 200-cylindro-conical tank (fitted with faecal chamber) with density of 10 fishes/tank. Faeces were collected at 3-h intervals between the morning and afternoon feeds for 7-10 days when sufficient sample had been collected for chemical analysis.

The results indicated that S.javus had the capability to digest protein of both plant and animal proteins except for crab shell meal and poultry offal meal whose APDCs below 70%. Similar trend was observed for ALDC.  In the subset experiment 3, plant protein of three seaweeds and corn meal had relatively high APDCs (> 75%). The ALDC of Caulerpa  and Euchema were higher than those of Ceratophyllum sp and yellow corn.