Evaluating the Effects of Dietary Prebiotic Mixture of Mannan Oligosaccharide and Poly‐β‐Hydroxybutyrate on the Growth Performance,Immunity, and Survival of Rainbow Trout,Oncorhynchus mykiss (Walbaum 1792), Fingerlings

This study investigated the effects of dietary poly‐β‐hydroxybutyrate (PHB) and mannan oligosaccharide (MOS) on the growth performance, digestive enzyme activities, and disease resistance of rainbow trout fingerlings. A total of 420 fingerlings, distributed equally into four different groups, each with three replicates, were fed a basal diet (control), 2% PHB (PHB), 0.2% MOS (MOS), or a diet supplemented with a mixture of 2% PHB and 0.2% MOS (PHB+MOS) for 60 d. Results showed that dietary PHB and/or MOS did not cause significant improvement in the growth performance of the fingerlings. The gut pH was markedly reduced; however, the activities of the digestive enzymes (except for pepsin and amylase by dietary PHB) were not significantly improved by the dietary supplements. Results also showed that dietary PHB and/or MOS markedly increased the resistance of the fingerlings toward Yersinia ruckeri infection, while the lowest total antibody was observed in fish fed control and MOS, indicating that MOS exerts its protective effects by modulating other mechanisms. Overall, this study provided a first screening effort to determine the effects of PHB and/or MOS as dietary supplements in rainbow trout fingerlings to develop an optimal prebiotic mix for improving the growth and health status of rainbow trout.     

Simulating the Production of Rice Genotypes by Flood Management and End-Season Water Stress Conditions Using AquaCrop Model

ABSTRACT

The present study was conducted to assess the ability of AquaCrop model in predicting of grain and biological yield of rice genotypes in water management. A two-year field experiment was conducted at the experimental farm of the Iranian Rice Research Institute in Rasht, Iran from 2016 to 2017. The experiment was established in a split-plot design with two irrigation management (continuous submergence and end season water stress) as the main plot, fourth rice genotypes as the sub-plot and three replications. The goodness-of-fit between observed and simulated grain yield and final biomass was assessed by means of the coefficient of determination (R ²), the absolute and normalized root mean square errors (RMSE). The RMSE_n of predicting grain yield at calibration and evaluation stages was in the range of 6–12% and 6–8% for biological yield. The results indicated that AquaCrop model is suitable to predict grain yield and biological yield of rice genotypes in northern Iran. AquaCrop model can be used to determine optimization strategies to improve the water consumption of rice genotypes.     

Salinity tolerance of wild barley Hordeum vulgare ssp. spontaneum

Salinity tolerance of 47 wild barley genotypes and six barley cultivars was evaluated under control and salinity stress (300 mM NaCl) conditions. Shoot and root dry weight (DW), plant height, membrane stability index (MSI), relative water content, survival rate, leaf malondialdehyde (MDA) and proline contents, root and leaf Na, K, Ca and K/Na ratio, and chlorophyll a fluorescence were measured. Salinity stress caused significant increase in the MDA, proline content, Na and Ca concentrations of the roots and leaves, but resulted in a decrease in the other traits. H. spontaneum genotypes were considerably less affected by the salinity than the genotypes of H. vulgare. Plant survivability was negatively correlated with the Na concentration (r =−.66) but positively correlated with the leaf K/Na ratio (r = .67) and MSI (r = .68). Tolerance mechanisms such as ion exclusion (Na) were likely to be present in the wild barley causing K/Na homeostasis as well as the much lower root and shoot Na, resulting in the higher survival rate.     

Fortification of Bread Wheat Using Synthesized Zn-Glycine and Zn-Alanine Chelates in Comparison with ZnSO4 in a Calcareous Soil

ABSTRACT

Calcareous soils typically suffer from zinc deficiency and zinc sulfate is incorporated in many cultivated soils. Utilization of ZnSO₄ has some kinds of interaction with soil particles and organic matter. In this study, the efficacy of two znic(Zn)-amino acid chelates (Zn-ACs) i.e., Zn-alanine (Zn-Ala) and Zn-glycine (Zn-Gly) on wheat (Triticum aestivum, cv. N91-8) growth characteristics and zinc concentration in wheat was examined under greenhouse conditions and compared to the a commercial ZnSO₄. Results showed that Zn-Ala and Zn-Gly significantly increased the dry weight and shoot length of wheat in comparison to ZnSO₄ treatment. Soil application of Zn-Amino acid chelates proved to be the most influential source of zinc in increasing wheat growth and yield indices. Number of fertile spikelet and grain yield increased significantly respectively compared to ZnSO₄ treatment. Zn concentration and protein content of wheat grain in Zn-ACs treatment was significantly higher than the ZnSO₄ treatment. Soil application of Zn-ACs caused a significant decrease in the grain phytic acid (PA) concentration and also phytic acid to zinc molar ratio in comparison with ZnSO₄ treatment. According to the results, Zn-ACs could be utilized as a zinc fertilizer source for improving the zinc bioavailability in wheat.     

Effect of Dietary Gamma‐irradiated and Fermented Soybean Meal on the Growth Performance,Body Composition,and Digestive Enzymes Activity of Caspian Brown Trout,Salmo trutta caspius,Juvenile

This experiment was conducted to evaluate the feasibility of gamma‐irradiated soybean meal (SBM) as a dietary ingredient on the performance, body composition, and digestive enzyme activity of Caspian brown trout, Salmo trutta caspius, juveniles. Five isonitrogenous and isoenergetic diets were formulated, in which fish meal was replaced by untreated (untreated SBM), gamma‐ray irradiated at 15 (15ISBM) and 30 (30ISBM) kGy, fermented (FSBM), fermented 15 KGy irradiated soybean meal (FISBM), respectively. Juvenile fish (2.1 ± 0.3 g) were fed with the test diets for 6 wk. Final body weight was significantly affected by dietary SBM treatment with highest values in fish fed FISBM and FSBM (P < 0.05). There were no significant differences in hepatosomatic and visceral indexes, condition factor, and survival among experimental groups (P > 0.05). The carcass proximate composition of lipid and protein in Caspian brown trout in FSBM and FISBM groups was higher than that of other groups. Levels of most whole‐body amino acids were not significantly different among Caspian brown trout fed the five diets. Results of this experiment showed that replacing SBM with FSBM and FISBM in the diet significantly increased the activities of proteolytic enzymes activities (P < 0.05). However, no significant differences were observed in both amylase and lipase activities among dietary treatments. Results of this study indicated that the level of gamma radiation used did not work but fermentation of SBM did increase some growth parameters of Caspian brown trout.     

Pathogenesis-related (PR)-proteins: Chitinase and β-1,3-glucanase in defense mechanism against malformation in mango (Mangifera indica L.)

Mango, the king of fruits in India is cultivated commercially in many tropical and subtropical regions of the world. Undoubtedly, mango malformation is a serious disease affecting mango production in India and many other countries around the world. It is now shown that the malady is inflicted by Fusarium, a fungus, and also that the plants have the capacity to suppress or reduce pathogen attack by inducing the synthesis of antimicrobial metabolites such as chitinase and/or the synthesis of lignin, both of which may enhance plant defense system. The present study was aimed at investigating the variability and relationship between activities of chitinase, β-1,3-glucanase and content of lignin in the leaves using 12 mango cultivars with the different degree of resistance to floral malformation. Results revealed that the activity of chitinase and β-1,3-glucanase in the leaves were significantly high in mango cultivars resistant to malformation (r = −0.90 and r = −0.91, respectively) during the flowering period, whereas lignin content did not show a significant correlation with malformation. The highest activity of chitinase (1.977–2.011 units) and β-1,3-glucanase (80.54–82.06 units) was recorded in resistant mango cultivars Bhadauran and Elaichi. In contrast, these activities were less than 1.010 and 25.21 respectively in highly susceptible mango cultivars such as Amrapali, Eldon and Neelum. Lignin content was highest in resistant cultivar Bhadauran, but it did not show significant relation to the malformation intensity of the cultivars. Thus, leaf chitinase and β-1,3-glucanase may be contributing towards resistance to malformation in mango and that the relative activities of these enzymes can be used as a criterion to predict and screen the mango germplasm and cultivars for resistance to floral malformation.     

Low developmental competence and high tolerance to thermal stress of ovine oocytes in the warm compared with the cold season

Tropical Animal Health and Production - Heat stress can potentially affect most aspects of reproduction in mammals. To our knowledge, no studies have ever been conducted for evaluating the...     

Basilaphelenchus gorganensis n. sp. (Aphelenchoidea,Tylaphelenchinae) from wood from northern Iran

Basilaphelenchus gorganensis n. sp. is described and illustrated from wood and bark of a dead tree from northern Iran. The new species is characterized by female body length (415–559 µm), three‐lined lateral fields, a sclerotized cephalic vestibule and cephalic framework, thin stylet with three elongate backwardly directed knobs, small spherical to oval metacorpus, with small and posteriorly located valve, simple vulva without any flap apparatus, 59‐ to 79‐µm‐long post‐vulval uterine sac, functional rectum and anus and dorsally convex, ventrally concave, usually ventrally bent conical female tail with a sharp tip. Males are common, apparently functional and characterized by well‐curved spicules, three pairs of small caudal papillae and no bursa at tail tip. Molecular phylogenetic inferences using partial sequences of small and large subunit ribosomal RNA genes (SSU and LSU rDNA) from different isolates of the new species revealed it differs from currently sequenced species and belongs to the Tylaphelenchinae clade.     

Sensitive variables controlling salinity and water table in a bio-drainage system

Bio-drainage can be considered as an important part of sustainable irrigation water management. Bio-drainage has potential for managing shallow water conditions in arid and semiarid areas especially when traditional subsurface drains are not available. Bio-drainage theory does not go back too far. The relationship between soil characteristics, water management regimes, and climatic conditions is not yet well defined. This study attempted to use a mathematical model (SAHYSMOD) to evaluate factors affecting design and operation of a bio-drainage system and study its sensitivity to different variables. The study showed that the major constraint of bio-drainage is salt accumulation in tree plantation strips in arid and semiarid regions. Maximum soil water salinity which can be controlled by bio-drainage is around 3 dS m^?1 in rather medium run and sustainability may only be achieved where a salt removal mechanism is considered. The study also showed that the effectiveness of the system is higher where the neighboring strips are narrower. It also showed that bio-drainage is very sensitive to the amount of applied water. While the barrier depth does not have an important effect on water table draw down, it does have a great influence on lowering the salinization rate of tree plantation strips. The application of bio-drainage could be economically controversial since in humid areas water is sufficient for agricultural crops, allocating parts of the expensive land to mostly non-fruit trees may not be feasible, while in arid and semiarid regions there is usually enough cheap land to grow trees.