Dietary barley inclusion to replace wheat, with or without carbohydrases supplementation in Pacific white shrimp (Litopenaeus vannamei) diets: Effects on growth performance, nutrient utilization, and physiological gene expression

Abstract

Supplementation of exogenous enzymes in barley-based diets could aid in hydrolyzing the non-starch polysaccharides (NSP). To investigate the effects of enzyme supplements in barley- based diets replacing wheat, a 5-week growth trial was conducted on Pacific white shrimp (Litopenaeus vannamei). Six isonitrogenous (35%) and isolipidic (7%) diets were formulated, namely, whole wheat-based (17.42 g/100 g diet) basal diet (BW); barley-based basal diet (BB); and four enzyme-supplemented diets were BB supplemented with either xylanase (XYL) or a multi-enzymatic solution (MES) at manufacturers’ recommended dose (low, L) and double the recommended dose (high, H) and denoted as BB:XYL-L, BB:XYL-H, BB:MES-L, and BB:MES- H, respectively. Shrimp (0.72 ± 0.03 g) were stocked in 108-L aquaria. Diets were randomly assigned, with six tanks replicates per treatment. At the completion of the trial, growth performance parameters, apparent digestibility coefficients (ADC), and physiological gene expression in hepatopancreas were analyzed. Results showed no significant differences in growth performance across treatments (p > 0.05). However, significant differences in ADC of energy (p = 0.010) and dry matter (p = 0.001) were observed. The BB:XYL-L diet significantly increased energy digestibility compared to the BB diet without enzyme supplementation. Nonetheless, dietary barley inclusion with or without enzyme supplementation in shrimp diets did not significantly (p > 0.05) impact the expression of tor, ghsr1l, cat, tgfβ, propo, lgbp, and hsp70 in the hepatopancreas. However, hierarchical clustering of multigene responses showed that BB:MES-L and BB:MES-H had gene expression profiles similar to BW. Based on these findings, barley could be used as a wheat replacement without compromising growth performance, and the addition of carbohydrase could enhance energy digestibility and physiological responses.