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Effect of Preslaughter Fasting Periods on Muscle Quality and Digestive Enzyme Activity of Farmed Whiteleg Shrimp Litopenaeus vannamei

ABSTRACT The effect of periods of preslaughter fasting on muscle quality and digestive enzyme activity of farmed whiteleg shrimp Litopenaeus vannamei was investigated. The fasting periods for the control, treatment 1 (T-1), and treatment 2 (T-2) groups were 0, 1, and 2 days, respectively. Higher compositions (P < 0.05) of crude protein and crude fat were observed between the control and T-2 groups. In addition, there was significant difference in crude fat between treatments T-1 and T-2. With regard to pH, total volatile basic nitrogen, and K value, no significant differences were detected across all groups; however, significant differences (P < 0.05) were obtained in hardness, springiness, and chewiness of shrimp muscle between the control and T-2 groups. According to the results of total viable counts, preslaughter fasting was most effective at controlling the growth of microorganisms. A significant difference was also observed (P < 0.05) in protease and lipase activities between the control and T-2 groups, which indicated that the 1-day fasting period prior to slaughter could firm muscle texture, increase enzyme activities, improve fat deposits, and decrease microbial growth of whiteleg shrimp, thus improving muscle-quality attributes of the whiteleg shrimp.