The effects of different levels of rapeseed meal in the diet of white shrimp (Litopenaeus vannamei) on in vitro digestibility and growth

Abstract

The study on the application of rapeseed meal as protein replacement for soybean meal at levels of 0%, 5%, 10%, and 15% was conducted by focusing on protein and carbohydrate digestibility. The in vitro digestion of Pacific white shrimp diets with rapeseed meal 5% control 0% rapeseed meal was in the same range when observing the release of amino acid and reducing sugar such as maltose, glucose, xylose and mannose. However, the inclusion rate of rapeseed meals at the level of 10% and 15% resulted in a decrease in the release of amino acids and the release of maltose, glucose and mannose when compared to the control diet without rapeseed meal (P<0.05). The study on the effect of rapeseed meal replaced soybean meal on the growth performance of Pacific white shrimp fed rapeseed meal diets, 0%, 5%, 10% and 15% showed that Pacific white shrimp in all treatments had similar growth performance (P>0.05) when considering on the final weight, weight gain, average daily gain, feed conversion ratio and survival rate. In addition, the study on the effect of replacing soybean meal with rapeseed meal on the immunity of white shrimp was conducted using diets containing 0, 5, 10 and 15% rapeseed meal. The results showed that the number of hemocytes in white shrimp fed 15% rapeseed meal was significantly reduced compared to the control diet (P<0.05). The effect on hemocyte protein and phenoloxidase activity of shrimp fed with the experimental diet containing 15% rapeseed meal tended to decrease but were not significantly different (P>0.05). Therefore, rapeseed meals could replace soybean meal in shrimp diets at the inclusion 15% without any adverse effects on growth performance and survival rate (p>0.05) However, the use of rapeseed meal in white shrimp diets more than 10% resulted in a statistically significant decrease in the