RESEARCH ARTICLE

Journal of Oil Palm Research Vol. 23 (1) April 2011, p. 953-957

FARMED FISH AS BIOLOGICAL AGENTS FOR EXTRACTING RESIDUAL PALM OIL IN DISCARDED SPENT BLEACHING CLAYS FROM THE PALM OIL REFINING INDUSTRY

NG Wing Keong * ; KOH Chik Boon *

ABSTRACT

Spent bleaching clays (SBC) from palm oil refining contain 20% to 30% adsorbed oil that cannot be recovered economically. This article highlights research conducted to evaluate the potential use of this waste product in the feeds of farmed fish. The impact of graded dietary levels of SBC on growth, feed utilization, body composition, fish health and water quality parameters in feeding trials conducted are discussed. High dietary levels of SBC can be incorporated into catfish and tilapia feeds without any significant negative impact on their growth and health. Nevertheless, total solids and total suspended solids concentration in tank culture water increased significantly concomitant to the increasing dietary levels of SBC fed to the fish. The issue of heavy metal accumulation in fish tissues will also be discussed in the context of current global legislation in regards to feed and food safety. The potential advantages and challenges in using palm oil-based SBC in aquafeeds will be highlighted. It is concluded that farmed fish can be effectively used as low-technology biological agents for the economical extraction of the adsorbed oil in SBC from palm oil refining. Application of this concept will bring benefits to the palm oil, aquaculture and waste disposal sectors.

KEYWORDS:


* Fish Nutrition Laboratory,
School of Biological Sciences,
Universiti Sains Malaysia,
11800 Minden, Pulau Pinang, Malaysia.
E-mail: wkng@usm.my