Feeding and waste management strategies in the culture of Clarias gariepinus

Nutrient digestibility and amino acid availability were assessed in sharp-toothed catfish, Clarias gariepinus, fingerlings fed diets containing soyabean flour (SF) - Poultry meat meal (PMM) blends (25:75. 50:50, and 75:25) and 0.5 of 1.0%, Cr sub(2)0 sub(3). There was agreement between the pattern of overall protein digestibility and average amino acid availability despite the variability in individual amino acid availability the best dry matter, lipid and protein digestibility coefficients, and amino acid availability values were obtained with diets containing 0.5% Cr sub(2)0 sub(3). Chromic Oxide inclusion level appeared to affect nutrient availability. Increased marker level resulted into decreased nutrient digestibility coefficients. Similarly, these diets generated lower fecal crude protein than those with 1.0% Cr sub(2)0 sub(3). However, the latter group recorded higher protein retention efficiency. Dry mailer and lipid of diets containing more soyabean flour seemed to be more digestible than those of poultry meat meal. Similar trend was observed for the apparent availability of the amino acids. This investigation has indicated that low level of marker was better in digestibility study. Utilization of more SF than PMM in the diets of this catfish was more beneficial and should be encouraged in the feed industries producing catfish diets towards a better feed and waste management strategies in this aquaculture operation

Packaging and storage studies of dried lizard fish

Packaging and storage studies of salted and dried lizard fish (Saurida sp.) have been conducted using different synthetic films like low density polyethylene (LDPE) of different gauges, high density polyethylene (HDPE) of 200 gauge, polyvinylidene chloride (PVDC) coated 400 MXXT cellophane, 100 gauge polypropylene (PP) and paper laminate of 100 gauge polythene. The films found most effective in the preliminary studies were subsequently used for packaging and storage of dried fish at atmospheric and lower temperature and humidity conditions for confirming their suitability under these conditions. Polyethylene films of higher gauges showed better results under both sets of conditions. PVDC coated cellophane film also performed satisfactorily under the latter conditions which under the former condition got easily attacked by insects. Lower temperature and humidity conditions in general enhanced the storage life of the dried product.

Study on shelf life of fish cake prepared from surimi of silver carp (Hypophthalmichthys molitrix) during frozen storage

Surimi was prepared from silver carp with an aim to put this underutilized fish for profitable use. The mince prepared was washed twice with chilled water (5°C) using mince to water ratio (w/v) of 1:2 for 5-6 minutes each. After final dewatering to moisture content to about 80%; half the quantity of washed minced meat was mixed with cryoprotectants (4% sorbitol, 4% sucrose and 0.3% sodium tripolyphosphate) to produce surimi. The prepared surimi and the dewatered minced meat were packed in LDPE bags, frozen using a plate freezer and stored at -20°C. Surimi and dewatered minced meat from frozen storage were used as base material for production of fish cakes. These were fried at 160°C for 3 to 4 minutes before serving for organoleptic test. Changes in salt soluble nitrogen, total volatile base nitrogen, non-protein nitrogen, peroxide value and free fatty acid of surimi and dewatered mince were estimated at every ten days interval during the storage period of 3 months. The study has indicated that frozen storage of surimi could be a potential method for effective utilization of silver carp. This surimi when incorporated in fish cakes yielded products which retained the shelf life even up to 90 days of storage.

Value-adding through coatings

The paper presents the three categories of food coatings that are used, individually or in combination, to produce battered or breaded foods. These are predust, batters and breadcrumbs. Predusts are usually a blend of flours, starches and other functional ingredients such as proteins, vegetable gums and seasonings or flavors; batters are blends of flours, starches, leavening agents and seasonings which, when mixed with water, forms a viscous liquid used to evenly coat a food item; while breadcrumbs are baked or otherwise thermally processed cereal-based ingredients which are applied to a moistened food item prior to cooking.