ResultsAmong all the treatments, fish survival rate ranged did not showany significant differences and values were higher than 85%. Asshown in [Fig-1], fish final mean weight decreased from fish fed thecontrol diet to those fed with 50% AM, values ranging from 88.8 gto 135.9 g.Mean values of fortnightly measurements of transparency (range:35.3-38.9cm), temperature (range: 29.8-30.2°C), pH (range: 6.33-6.62), dissolved oxygen (range: 4.65-5.49mg l-1), nitrite (range:0.01-0.02mg l-1), nitrate (range: 0.22-0.32mg l-1), ammonium(range: 0.28-0.43mg l-1), total nitrogen (range: 0.70-0.79mg l-1),chlorophyll a (range: 16.8-18.7μg Chla l-1) and zooplankton abundance(range: 759-862 ind.l-1) did not show significant differencesbetween triplicates (P>0.05).Significant variations in SRP (range: 0.14-0.38mg l-1) and totalphosphorus (range: 0.63-1.22mg l-1) were found (P<0.05) [Table -2], with higher concentrations in ponds A0 and A10 than in other treatments. The P content of soil matter (range: 0.01-0.02%) wasidentical in all ponds (P>0.05). Lower values of soil organic matterwere observed in ponds receiving A40 and A50 in comparison withthose receiving A0, A10, A20 (P<0.05) [Fig-2]. As shown in [Fig-3],the C/N ratios of food were quite similar (range: 8.9-10.8) while thesoil C/N atomic ratios (range: 6.7-19.6) decreased significantly, with lower values in ponds receiving high AM (P<0.05).Nitrogen from Azolla in diets provided to fish per group of pondswas plotted with the soil C/N ratio of each pond [Fig-4]. The C/Nratio was directly influenced by AM-nitrogen provided (R²= 0.79;P<0.001).
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