The larvae of the Pacific white shrimp Litopenaeus vannamei are fed, from the stage of protozoea I until to protozoea III (PZ III), with microalgae. The survival rate, duration of the terms of Z I -Z III and total length of protozoea larvae (PZ) of L. vannamei were survived. The shrimp larvae fed with the six treatments of microalgae (Chaetoceros muelleri, Isochrysis galbana, Tetraselmis tetrathele, C. muelleri : I. galbana, C. muelleri: T. tetrathele and I. galbana: T. tetratheie). The biochemical composition (protein, carbohydrate, lipid and energy) of the algae and the larvae fed those algae were also measured. The largest sizes were recorded for larvae fed with the mixture C. muelleri and I. galbana (4.35 mm) and smaller sizes were observed on larvae fed with I. galbana (3.04 mm) (P \ 0.05). The larvae fed with mixture T. tetrathele and C. muelleri (88.42 %) and I. galbana and T. tetrathele (84.50 %) had the highest survival in experimental treatments. The lowest time for development was observed in larvae fed with mixture of T. tetrathele and C. muelleri (92.6 h). The larvae fed with mixture I. galbana and T. tetrathele had the highest protein and carbohydrate levels as compared with other treatments. Also highest lipid level and gross energy were shown in larvae fed with mixture C. muelleri and I. galbana (P \ 0.05). The results showed that L. vannamei larvae fed with C. muelleri and the mixed diets containing this species (C. muelleri ? Isochrysis sp., C. muelleri ? Tetraselmis sp.) had the highest growth and survival among treatments.

This study was to evaluate the effect of a preparation of Bacillus probiotic (Bacillus licheniformis and B. subtilis, 1:1) on growth and survival rate of Pacific white shrimp, Litopenaeus vannamei larvae. The larvae were fed on Artemia urmiana nauplii and Brachionus plicatilis enriched with the probiotic preparation at 1 × 10(6) CFU mL(-1) rate. The experimental setup was completely randomized design comprised of six treatments, namely solo Artemia nauplii (A) or rotifer (R), Artemia nauplii and rotifer without any enrichment (A + R), Artemia nauplii enrichment with probiotic bacilli (Bacillus licheniformis and B. subtilis) (A + B), rotifer enrichment with probiotic bacilli (R + B) and enriched Artemia nauplii and rotifer (A + R + B). All treatments were performed in triplicate. Chemical parameters of rearing water viz. pH, salinity and temperature were 7.5-8, 30-31 ppt and 31-32 °C, respectively. Photoperiod was 16L:8D. Shrimp larvae were fed Artemia nauplii and rotifers at 5-20 and 10-40 individuals per shrimp larvae four times a day, respectively. Growth and survival rate of larvae were determined at MII, MIII, PL1, PL4, PL7 and PL10 stages. Larvae in A + R + B treatment showed the highest total length (10.89 ± 0.51 mm), weight (674 ± 73 μg) and survival rate (65% ± 3.5). Lowest total length, weight and survival rate (7.96 ± 0.63 mm, 493 ± 52 μg and 24.5 ± 2.4%, respectively) were recorded in treatment B larvae. We concluded that Bacillus probiotic can improve growth and survival rate of Pacific white shrimp larvae without conceivably undesirable effects.

Summary Length–weight relationships have been determined for two species, Mastacembelus mastacembelus and Glyptothorax silviae. Samples were taken in 2011 from the Cholvar River in western Iran. It is believed that the size range covered is close to a commonly known size range of each species. The length–weight relationship values of b were determined as 2.66 for M. mastacembelus and 3.045 for G. silviae. However these data are based on preserved specimens, and a correction factor for live lengths and weights is still warranted.