Suitability of two agglomerated commercial microdiets for rearing larvae of different strains of Coregonus lavaretus under cold‐water conditions

The suitability of two agglomerated commercial microdiets (“Gemma micro^®” and “O.range^®” from now on called diet A and diet B) as a starter feed was tested on larvae of European whitefish (Coregonus lavaretus). Two strains (Baltic and Alpine) were tested in a 60‐day experiment under ambient cold‐water conditions (average 7.6 ± 1.9°C). The experiment was carried out in 400‐L PVC tanks with a stocking density of 5,000 larvae per tank. Samples were removed weekly to determine growth, survival and feed acceptance, in addition to water quality. Striking differences between the feeds and different strains were observed. For one diet, growth and survival were distinctively higher in strain 1 compared to strain 2, where it was invariably low with both diets. For the second diet, growth and survival in strain 1 were also low and similar to strain 2. Feed acceptance in strain 1 was found higher compared to strain 2. Final weights were significantly different with strain 1 being heavier; however, in terms of relative growth rate, no differences between strains were found. Strong differences in the performance in terms of growth, survival and feed acceptance of different strains of European whitefish became apparent. Furthermore, the rearing of larvae exclusively on standard agglomerated commercial microdiets under cold‐water conditions is possible, but not every microdiet is suitable.     

Induction of Immunogenic Response in BALB/c Mice by Live and Killed Form of Recombinant Lactococcus lactis Displaying EG95 of Echinococcus granulosus

Background:CE is a zoonotic parasitic infection caused by Echinococcus granulosus worldwide and is associated with economic losses among livestock animals. EG95 is an immunogenic antigen from the E. granulosus. Lactococcus lactis has been prested as a safe vehicle for antigen delivery. The goal of this study was to design a novel L. lactis strain displaying EG95 as a vaccine delivery system. Methods:The eg95 encoding gene fragment fused to the M6 anchoring protein was cloned into the pNZ7021 vector, and L. lactis NZ9000 displaying recombinant EG95 was constructed. The expression of an approximately 32-kDa EG95 protein was confirmed by Western blotting and immunofluorescence analysis. The immune responses were evaluated in BALB/c mice immunized orally and subcutaneously with the live and killed recombinant L. lactis, respectively. Results:Total IgG level in mice immunized with heat-killed recombinant L. lactis (pNZ7021-eg95) significantly increased compared to the control group. sIgA was significantly higher in mice received live recombinant L. lactis (pNZ7021-eg95) compared to the control mice. Splenic lymphocytes from immunized mice represented the high levels of IFN-γ and the low-levels of IL-4 and IL-10. Conclusion:Our results indicate that immunization with EG95-expressing L. lactis can induce both specific humoral and cellular immune responses in mice. Key Words: Echinococcus granulosus, Lactococcus lactis, Immunization, Vaccines     

Assessment of NK cells response to hepatocyte derived chemotactic agents

This project was aimed to examine the NK92 cells response as the CXC chemokine responder cells in rat model of liver disorder and injuries. Hepatocytes were isolated from Sprague-dawly rats and cultured on collagen type 1. Migration of NK92 cells was assessed using a 48 well micro-chemotaxis technique. Transwell chambers were positioned faced up, blocked Medium supernatant (500 microL) obtained from hepatocytes cultures were placed into the lower compartment of each Transwell. The upper compartment was filled with either 500 microL of NK92 cells. After washing, Membrane-attached cells were fixed; stained and Membrane-attached cells were counted by light microscopy and/or by size gating (9-14 microm) with an automated counter system. Human NK92 cells were attracted to recombinant human IP-10 in a concentration and time-dependent manner. NK92 cells also exhibited a chemotactic response to medium harvested from primary hepatocyte cultures. Isolated and cultured hepatocytes express several different chemokines. Although we identified that medium from hepatocyte cultures contains specific chemokines by immunoblotting, there is potential that migration assays detected yet other chemokines and other factors such as complement components. In this report, we demonstrated that hepatocytes expressed factors that were chemoattractive for human NK92 cells and that the factors must interact with the repertoire of receptors responsible for recruitment of these cells.     

Assessment of genetic diversity in bread wheat genotypes for tolerance to drought using AFLPs and agronomic traits

Moisture stress greatly limits the productivity of wheat in many wheat-growing regions of the world. Knowledge of the degree of genetic diversity among parental materials for key selection traits will facilitate the development of high yielding, stress tolerant wheat cultivars. The objectives of this study were to: (i) use amplified fragment length polymorphisms (AFLPs) to assess genetic diversity among bread wheat lines and cultivars with different responses to drought stress in two distinct environments and, (ii) compare genetic diversity estimated by AFLPs with diversity evaluated on agronomic performance under drought stress. Twenty-eight genotypes, 14 from Iran and 14 developed or obtained by CIMMYT, were evaluated in the study. Phenotypic data on the 14 Iranian lines were obtained in Iran, and data on the 14 CIMMYT lines were collected in Mexico. Ten AFLP primer pairs detected 335 polymorphic bands among the 28 cultivars. At the 5th fusion level of the resulting dendrogram, 6 genotype clusters were identified. Thirteen of the 14 CIMMYT genotypes grouped into one cluster while 4 of the remaining groups were comprised only of Iranian genotypes. When the agronomic performance of the Iranian materials was compared with the AFLP diversity analysis, 5 of the 6 drought susceptible genotypes clustered together in the agronomic dendrogram, and were located in the same cluster in the AFLP dendrogram. However, the drought tolerant Iranian materials did not show the same degree of relationship. The CIMMYT materials did not demonstrate a significant association between agronomic performance and genetic diversity determined using AFLPs. Clearly these data show that there are genotypes with similar agronomic performance and different genetic constitutions in this study that can be combined in a breeding program to potentially improve tolerance to drought stress.     

Growth performance,nutrient digestibility and lipase activity in juvenile rainbow trout (Oncorhynchus mykiss) fed fat powder in diet containing emulsifiers (cholic acid and Tween‐80)

This research was conducted to investigate the effects of two dietary emulsifiers on nutrient digestibility and lipase activity in rainbow trout (Onchorhyncus mykiss). A basal rainbow trout diet containing fat powder supplemented with 10 and 5 g kg^?1 of cholic acid, and 20 and 40 g kg^?1 of Tween‐80. Control diet contained no emulsifiers with fat powder was replaced by fish oil. Each diet was randomly assigned to 1,500‐L tanks in triplicate. Juvenile rainbow trout with an initial weight of 27.32 ± 2.03 g were randomly distributed in the experimental tanks. The results showed that growth parameters did not change by the addition of the two emulsifiers (p > .05). Total triglyceride content was significantly higher in control fish fed diet containing fish oil (p < .05), while serum cholesterol content showed no significant differences among treatments (p > .05). Control diet resulted in a higher fat digestibility than those of other experimental diets. However, protein and ash digestibilities in diet containing emulsifier were higher than those of the control diet. Control group showed the lowest lipase activity, whereas 20 g kg^?1 Tween‐80 diet caused the highest lipase activity among treatments (p < .05). In conclusion, it seems that a higher lipase activity induced by the emulsifiers could not compensate for the negative impacts of fat powder on the experimental diets.