This study was carried out to evaluate the effect of replacing Dunaliella salina algae by agricultural by-products (wheat bran, rice bran and wheat/rice bran) and probiotic bacteria Lactobacillus rhamnosus on digestive enzymes activity of Artemia franciscana in a 17-day period post hatch. The study was a 4×2 factorial experiment carried out as a completely randomized design trial consisting of different dietary treatments (combinations of various substitution levels of Dunaliella salina by wheat bran, rice bran and wheat/rice bran along with probiotic Lactobacillus rhamnosus). All treatments were performed in triplicates. At the end of the trial, digestive enzymes activity was assayed. The results revealed that Artemia fed wheat bran without any dietary probiotic supplementation showed significantly higher amylase activity (2.06±0.3μmol maltose mg protein^-1 min^-1) (p<0.05). Treatment fed Dunaliella salina algae and probiotic showed significantly higher alkaine protease activity (7.11±0.87 U mg protein^-1 min^-1) and those fed wheat/rice bran with probiotic had significantly higher lipase activity (0.09±0.005 mmol p-nitrophenol mg protein^-1 min^-1) (p<0.05). It was revealed that dietary probiotic inclusion resulted in decreased amylase activity whilst its effect on the alkaline protease and lipase activities were totally dependent upon the feed ingredients (e.g., simultaneous feeding of artemia by Dunaliella salina algae and probiotic led to higher alkaline protease activity, while receiving probiotic resulted in higher lipase activity in group fed wheat/rice bran). Our results also showed that digestive enzyme profile of Artemia franciscana was responsive to dietary treatment. Conclusively, using wheat/rice bran in artemia pond culture would result in inferior digestive enzymes activity especially alkaline protease and lipase with subsequent effects on nutrient digestion/absorption efficiency and undesirable effects on pond productivity and final product quality.

The aim of this study was to evaluate the effect of partial replacement of Dunaliella salina algae with wheat and rice bran and Lactobacillus rhamnosus probiotic on growth indices, approximate qualitative factors and the fatty acid profile of Artemia franciscana during 17 days culture period. The present research was designed as a 2×4 factorial experiment in a completely randomized design with 8 treatments and three replicates. The treatments were different in terms of the type of diet (wheat bran, rice bran, mixture of wheat bran, rice bran and Dunaliella salina algae) and also in the probiotic level (0 and 10 percent of daily diet). At the end of experiment the samples were collected to measure the growth parameters, carcass composition, and fatty acid analysis. The results indicated that the Artemia in treatment 2 (85% wheat bran, 15% D. salina) exhibited the highest level of total fat (21%), saturated fatty acids, SFA, (11.90 ± 2.54 mg g^-1 wet tissue), unsaturated fatty acid with one double bond, MUFA, (18.56 ± 3.22 mg g^-1 wet tissue), linoleic acid, LAN, (10.79 ± 1.43 mg g^-1 wet tissue), ash ( 12.15 ± 0.29%) and the lowest food conversion rate, FCR, (1.51 ± 0.03) compared to other treatments (p<0.05). Moreover the treatment 4 (42/5% wheat bran, 42/5% rice bran, 15% D. salina) demonstrated lowest level of specific growth rate (SGR), (27.97 ± 0.05) and dry weight percentage of carcass (7.98 ± 0.08%) among other treatments. The treatment 1 (100% D. salina) showed the lowest ash and the highest FCR and DHA and EPA fatty acids compared to other treatments (p<0.05). Finally we can conclude that wheat bran and combination of wheat bran with probiotic may be the most suitable alternative food to replace D. salina in A. franciscana diet.