Improvement in Nutritional Quality of Shrimp Meal with Autoclave and Chemical Treatments: an in vitro Study

The present study was conducted to improve the nutritional quality of shrimp meal (SM) comprising of heads with hulls of black tiger shrimp (Penaeus monodon) waste by autoclaving and chemical treatments. The sun-dried SM was divided into 5 treatment groups, such as 1) control (untreated), 2) autoclaved (autoclaved at 121°C for 10 min), 3) NaOH (treated with 3% NaOH), 4) HCl (treated with 3% HCl) and 5) formic acid (treated with 3% formic acid) groups. After treatment, they were ground to pass through 1.0 mm mesh screen and then used for analyses of chemical composition and in vitro dry matter (DM) and CP digestibilities. Data were subjected to one-way ANOVA and differences among treatment means (P<0.05) were distinguished with Tukey's test. There were no significant difference in chemical composition and in vitro DM and CP digestibilities between control and autoclaved groups, except ether extract level (P<0.05), suggesting that autoclaving affected the nutritional quality of SM little. NaOH group exhibited significantly decreased CP level and in vitro DM digestibility, increased crude ash (CA) level and unchanged in vitro CP digestibility, comparing with control group. These results suggest that NaOH treatment affected the nutritional quality of SM adversely. HCl and formic acids groups showed significantly increased CP level and in vitro digestibilities of DM and CP, and decreased CA level, showing that acid treatment can improve nutritional quality of SM: formic acid treatment may be more effective because of the greater values in CP level and digestibilities and decreased crude fibre level which was not observed in HCl group (P<0.05). The results obtained here suggest acid, especially formic acid, treatment is promising to improve the nutritional quality of SM but autoclaving and NaOH treatments.