Effect of fungal fermentation on the nutrient digestibility of guar meal in Penaeus vannamei

A 30-days indoor feeding trail was carried out to determine the nutrient digestibility of untreated and fermented guar meal (GRM) in Penaeus vannamei. The fermented guar meal was prepared by solid state fermentation using the fungus Aspergillus niger. A reference diet was formulated based on the dietary requirements of shrimp and test diets were prepared using the ingredient substitution method of reference diet and test ingredient at 7:3 ratio. Results revealed that the fungal fermentation significantly (p<0.05) increased dry matter digestibility of GRM from 48.86 to 54.27% and crude protein digestibility from 64.41 to 68.54%. Significant (p<0.05) improvement was observed in the digestibility of all the aminoacids with fermented GRM compared to the untreated GRM. The range of essential amino acids digestibility was increased from 59.4-69.6% to 61.5-73.6% post-fermentation. Lysine in essential amino acids and serine in nonessential amino acids showed the highest digestibility in both untreated and fermented GRM whereas a better improvement was observed witharginine (9.79%) and glutamic acid (8.59%) due to fermentation. The present results of increased digestibility parameters in fermented GRM were attributed to the amelioration of anti-nutritional factors and reduction of fibre fractions.