Preliminary Studies On The Effects Of Different Processing Methods On The Nutritive Value Of Shrimp Waste Meal
The effects of processing methods viz oven-drying, acid-treatment and sun-drying on the nutritive value of shrimp waste meal (SWM) was examined. Five purified diets were formulated. A basal diet (Nitrogen-free), a reference diet that contained whole hen's egg and three test diets that contained oven-dried, acid-treated and sun-dried SWM as their protein sources respectively. The reference and test proteins were added to supply 100g/kg crude protein in the different diets at the expense of corn starch in the basal diet. Feed and water were given ad libitum throughout the period of experiment that lasted 14 days. Oven-dried SWM had the highest crude protein and nitrogen-free extracts (NFE) contents (366.0; 85.4g/kg) compared to the acid- treated (344.2; 59.6g/kg) and sun-dried SWM (328.0; 42.6g/kg). The ether extract or the SWM samples were generally low, no traces of fat could be found in the oven-dried shrimp waste (SW). The sun-dried SW sample had the highest ash contents while the acid-treated SW had the lowest. The oven-dried and sun dried samples consistently contained higher amounts of Ca, P, Mg, K, Mn and Na more than the acid treated SW. The latter however contained appreciable quantities or Fe, Cu and Zn in
comparison with SW processed by the other two methods. Rats fed the oven-dried SW had the best performance (P< 0.05) in terms of body weight. The protein efficiency ratio (PER) and Net protein retention (NPR)
showed the same trend as the weight changes. The relative weights of the lungs, kidney, heart, liver and spleen of the experimental animals did not vary significantly (P< 0.05) with the dietary treatments. It was concluded that oven-drying seemed to be the best out of the processing methods employed for shrimp waste in this study but the results are poorer (P< 0.05) than those obtained for the reference protein.
Keywords: Processing methods, shrimp waste, Nutritive value