COMPARATIVE EFFECT OF PRACTICAL DIETS FORMULATED WITH Chlorella, Spirulina, OR SOYBEAN MEAL MATRICES ON THE GROWTH AND DIGESTIVE ENZYMATIC ACTIVITY OF Macrobrachium tenellum PRAWNS

Developing nutritionally effective plant-based feeds is important for reducing dependence on animal-derived ingredients in freshwater prawn aquaculture. Wild juvenile Macrobrachium tenellum prawns were collected from a coastal river in Oaxaca, Mexico, and transported to the laboratory. Prawns were reared using a completely randomized experimental design with three dietary treatments featuring different plant protein matrices (Diet 1: Chlorella, Diet 2: Spirulina, and Diet 3: soybean meal), with four replicate tanks per treatment (15 prawns per tank). Over a 60-d culture trial, survival, growth (weight gain), and feed conversion ratio (FCR) were evaluated on days 0, 20, 45, and 60. Survival calculations were systematically adjusted for organisms removed during sampling. At each sampling point, two live specimens per replicate unit were collected for analysis of digestive enzyme activity (alkaline protease, trypsin, chymotrypsin, lipase, and α-amylase). Data were analyzed using two-way analysis of variance (ANOVA), Tukey’s test (p < 0.05), and principal component analysis (PCA). Results indicated that the Chlorella-supplemented diet (D1) yielded significantly higher final growth, a lower FCR (1.7), and greater overall digestive enzyme activity than Spirulina (D2: 0.3746, FCR 1.96) and soybean meal (D3: 0.2945, FCR 2.23). Overall survival ranged from 72 to 74 %, with no statistically significant differences among treatments (p > 0.05), although the soybean meal diet exhibited the highest numerical survival. Complete practical diets incorporating microalgae matrices, particularly Chlorella, significantly enhanced growth performance and digestive enzyme activity in M. tenellum without affecting survival.