Written by Mae Catacutan, SEAFDEC-AQD

Preparation of crab fecal matter samples in the lab to determine digestibility of nutrients (Photo from the Inland Aquatic Resources Division (IARD))

Basal diet for mud crab which can be used to supplement traditional or natural crab feed by 50 percent has been identified in a study.

Dr. Mae Catacutan of the Southeast Asian Fisheries Development Center, Aquaculture Department (SEAFDEC-AQD) in Tigbauan, Iloilo conducted the study.

With funding support from the Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development of the Department of Science and Technology (DOST-PCAARRD), the project seeks to identify a formulated feed for grow-out culture of mud crab.

In specific terms, the study aimed to identify a basal diet replacement for natural or traditional crab feed like fish-by-catch (FBC) by 50% and make an adequate formulated pelleted feed that is water-stable for five hours.

Ideally, basal diet for mud crab contains 48% crude protein and 5-6% crude fat with an estimated dietary energy of 1723 MJ/kg.

Using three test diets with three different crude protein (CP) contents, the study proved that a basal diet with 48% CP has better numerical values in terms of feed conversion ratios and specific growth rates.

Moreover, the study also showed that pellets with synthetic binders proved to be more water stable than pellets with natural binders. Three synthetic binders and natural binders (glutinous rice starch and carrageenan+CMC) showed best results.

The study further showed that carrageenan combined with a synthetic binder improved apparent digestibility coefficients of crude protein and crude fat.

To further test the efficiency and effectiveness of this formulated feed, pilot testing and technology roll out will be conducted to produce large quantities of feed for crabs in ponds.

Fiberglass tanks for the mangrove crab feeding experiment (Photo from IARD)