Protein Digestibility of Ingredients in Banana Shrimp Fenneropenaeus merguiensis (De Man, 1888)

Abstract

Background and Objectives : Banana Shrimp (Fenneropenaeus merguiensis) is one of the economically important domestic species of marine shrimp in Thailand. Banana Shrimp culture has not been succeeded since the lack of basic knowledge, including the specific shrimp feed for Banana Shrimp has not been successfully formulated. This study aimed to determine the protein digestibility of shrimp feed raw materials using in vitro technique with crude enzyme extract of shrimp larvae from protozoeal 1 (PZ1) to postlarval 60 (PL60) stages, in order to establish the data base for Banana Shrimp feed development and formulate the efficient shrimp feeds, which meet the shrimp nutrition requirements for growth and stage development, with the highest feed utilization and the least of waste to reduce the environmental problems, as well as cost saving and cost effectiveness of formulated diet for successfully and sustainably Banana Shrimp culture in the near future.

Methodology : Banana Shrimp gravid females from the wild were transferred to the hatchery in Chonburi Aquatic Animal Feed Research and Development Center.  Shrimp larvae were hatched and nursed and larval samples were collected at protozoeal (PZ) 1-3, mysis (M) 1-3, postlarval (PL) 1, 20, 30, 40, 50 and 60 stages and then stored at -80 °C until analyzed. Then crude enzyme was extracted using 50 mM Tris-HCl buffer, pH 8, then the supernatant was collected and stored at -80 °C for further analysis. There were 10 feed ingredients tested: - Artemia, soybean meal, soybean meal hydrolysate, shrimp head meal, squid meal, fish meal, krill, yeast, Spirulina and marine fish waste protein hydrolysate. For in vitro digestibility, Trinitrobenzene sulphonic acid (TNBS) was determined in the feed ingredients which were digested with crude enzyme from Banana Shrimp, compared to DL-alanine standard curve as µmol DL-alanine per g feed per trypsin specific activity. Trypsin specific activity (µmol p-Nitroaniline) was measured using 1.25 mM bensoyl-L-arginine-p-nitroanilide (BAPNA) as substrate and p-Nitroaniline as a standard. For total protein was determined followed the method of Bradford and bovine serum albumin (BSA) was used as a standard. The protein digestibility of feed ingredient data were subjected to Analysis of variance (One-way ANOVA) and Duncan's New Multiple Range test at 95% confidence interval (p < 0.05).

Main Results : It was found that for all stages of Banana Shrimp larvae (PZ1- PL60), the significantly (p<0.05) highest protein digestibility was marine fish waste protein hydrolysate (MFH). The following ranks differed among the stages of shrimp. On the other hand, soybean meal and soybean meal hydrolysate had the significantly (p<0.05) lowest digestibility in all stages (PZ1- PL60) of Banana Shrimp. When compared the protein digestibility of MFH and fish meal, which is the main protein raw material from animal in shrimp feed, the digestibility of MFH was 1.64-2.85 times higher than those of fish meal in every stage of tested Banana shrimp larva. It was even higher when compared to the protein digestibility of soybean meal, which is the main protein raw material from plant in shrimp feed, the digestibility of MFH was 11-22 times and 45-67 times higher than those of soybean meal in PZ1 to PL1 and PL20-60 stages, respectively. For trypsin activity of Banana Shrimp larvae, it was peaked at PZ2 and slightly declined in PZ3, but the average trypsin in PZ stages were higher than those of Mysis and the later stages.  The activity dropped, when the larvae developed into M1 stage, and continued decreasing through M2 and M3. When the larvae metamorphosed into PL1, trypsin activity increased again. As the activity defined per protein unit, therefore, the bigger the size of larvae, the smaller the trypsin activity from PL20-PL60 stages.

Conclusions : Banana Shrimp, from PZ1 to PL60 stages, had the highest efficiency for MFH protein digestibility. The following ranks differed among the stages of shrimp. Yeast, fish meal, squid meal and Spirulina were in high digestible protein ingredients group, followed by shrimp head meal, krill and Artemia. While the digestibility efficiency of hydrolyzed soybean meal and soybean meal of the PZ1 to PL60 stages of the shrimp was the lowest. MFH- marine fish waste protein hydrolysate has the potential to be used as an alternative shrimp feed ingredient, especially to replace fish meal at an appropriate level. It is a valuable use of waste, reduces waste, and increases nutritional value. For the specific trypsin activity in Banana Shrimp, it showed the suitable feeding for juvenile shrimp in each stage: - protozoa stage feeding on phytoplankton (herbivores), mysis stage feeding on both phytoplankton and zooplankton (omnivores) and postlarval stage feeding on zooplankton (carnivores), respectively. From the results of the efficiency of protein digestibility of shrimp feed raw materials and trypsin activity in Banana Shrimp from PZ1-PL60 stages could be the guidelines for formulating the feed formula for Banana Shrimp culture in the future.