Concentrated pineapple extract and Na-Cid ® facilitates the digestion of soybean meal and shrimp feed

Soybean meal has been used as an alternative plant protein source to replace fishmeal in shrimp feed for decades. However, the use of soybean meal is problematic owing to low digestibility in the digestive tract of shrimp and anti-nutritional factors that are found in plant derived protein. In addition, the residues of undigested feedstuff have been found to cause inflammation in the digestive tract of shrimp leading to white feces syndrome (WFS). This disease negatively affected the production of Pacific white shrimp (Litopenaeus vannamei) in Southeast Asia including Thailand. The study examined the ability of concentrated pineapple extract and Na-Cid ® to increase the digestibility of soybean meal and shrimp feed via protease activity. The results clearly showed that Na-Cid ® could facilitate the digestion of soybean meal and shrimp feed over a wide range of pH and temperature. The proteins released from Na-Cid ® treated soybean meal and shrimp feed were highest at a pH range between 5.0 and 8.5 while the lowest amounts were found at pH 4.0 and 9.0−10.0, respectively. Test temperatures in the range of 25−50°C did not affect the ability of Na-Cid ® to facilitate digestion. The results showed that Na-Cid ® was able to increase the digestion of protein in soybean meal and shrimp feed by approximately 18−26% and 27−33%, respectively. It is demonstrated the capability of the concentrated pineapple extract to increase in vitro digestibility of soybean meal protein. Our finding may provide a potent pretreatment procedure to solve the problem regarding the digestibility of protein in feedstuff leading to reduce the undigested residues remaining in the digestive tract of shrimp and the subsequent occurrence of white feces syndrome (WFS).