Six new botanical varieties of <Emphasis Type="Italic">Triticum</Emphasis> from Oman

Due to its geographic position on the northeastern tip of the Arabian Peninsula and its sea trade relationships with Asia, East Africa and the Middle East, Oman has for millennia been at the cross-roads of inter-regional exchange of cultivated plants. This is reflected in recent findings of new cultivars of banana (Musa spp.) and wheat (Triticum spp.) in remote oases of the Hajar Mountains in northern Oman. Material collected in 2003 and 2004 contained six new botanical varieties of wheat which are described here. One of them belongs to the tetraploid T. aethiopicum, the others are hexaploid.     

A novel Henneguya species from channel catfish described by morphological, histological, and molecular characterization

Channel catfish Ictalurus punctatus from a commercial farming operation in the Mississippi Delta were submitted for examination for the presence of infection by the trematode Bolbophorus damnificus. The fish were instead found to possess skin nodules suggestive of Henneguya pellis, a species previously described in the blue catfish I. furcatus. Despite the dermal location and distribution of lesions, morphological characteristics of the myxospores were inconsistent with H. pellis. Spores possessed a lanceolate spore body 15.4 +/- 1.5 microm (mean +/- SD; range = 12.2-19.3 microm) in length and 5.5 +/- 0.6 microm (range = 4.5-6.8 microm) in width in valvular view, and 4.7 +/- 0.2 microm (range = 4.2-5.0 microm) in width in sutural view. Polar capsules were pyriform and unequal in both length and width and contained polar filaments with six coils. Polar capsules measured 6.1 +/- 0.8 microm (range = 4.0-7.9 microm) long and 1.7 +/- 0.3 microm (range = 1.0-2.2 microm) wide. The caudal appendages were 50.5 +/- 8.3 microm (range = 34.8-71.4 micorm) long and the total length of the spore was 65.9 +/- 8.6 microm (range = 48.2-90.0 microm). The "blister like" plasmodia were round or ovoid, up to 2 mm in diameter, and randomly distributed throughout the epidermis of the fish. Histologically, plasmodia were confined to the dermis and elicited no inflammatory reaction from the fish. A blast search of the 18S small subunit rDNA sequence obtained by polymerase chain reaction amplification resulted in no identical sequence matches but indicated a close relationship to H. gurlei, H. ictaluri, and H. exilis. The unique host record, spore morphology, and novel genetic sequence derived from this isolate lead us to propose this isolate as a novel species, H. sutherlandi.     

Reduction of bacterial infections in newly hatched chicks by the use of antimicrobial dips: Preliminary approaches

Summary

Bacteriological examination of hatchery waste eggs, identification of the isolated bacteria, and susceptibility testing against seven antimicrobial agents were used in an attempt to establish a rational basis for reducing bacterial infections in newly hatched chicks.

Chloramphenicol at 1000 ppm was selected as the antibiotic for preliminary dipping trials and 0.45% iodophore (Wescodyne) was added for later trials. The control treatment consisted of formaldehyde fumigation. The following conclusions can be drawn:

(1) Hatchery waste eggs are highly contaminated (69.1%) and enterobacteriaceae predominate (26.6%).

(2) Chloramphenicol is the most effective antimicrobial tested.

(3) Dip treatments with either chloramphenicol alone or chloramphenicol plus Wescodyne result in a reduced percentage of abnormal navels (8.4% and 10.4%), as compared with 21.9% for the control treatment.

(4) Hatchability of either group of dipped eggs is reduced in comparison with fumigated eggs.

(5) Dip treatment with chloramphenicol plus Wescodyne significantly reduces the anal carrier rates for Escherichia coli, Pseudomonas aeruginosa, Salmonella spp., and Staphylococcus aureus. This treatment reduces the incidence of bacterial infection in abnormal navels to zero.     

The impact of foliar fertilizers on growth and biochemical responses of Thymus vulgaris to salinity stress

Salinity reduces plant biomass and may lead to death when severe. To cope with the negative effects of this stress, plant species present specific physiological or biochemical responses. In this work, we hypothesized that spraying salt-stressed thyme leaves with K⁺ and Ca²⁺ could mitigate the negative effects of salinity on plant growth and metabolism. To test this hypothesis, we grew thyme plants under salinity stress for two and four weeks before applying foliar sprays. Also, to test the effect of stress relief, treated plants were allowed two weeks of recovery after four weeks of salt stress. In general, after two and four weeks of salinity stress, the leaf fresh weight of thyme plants was reduced by 31 and 43%, respectively. Salinity also decreased the relative water content, water, and osmotic potentials and led to ion imbalances and nutrient deficiencies. Salinity altered concentration of some essential oils, but leaf antioxidant contents remained fairly stable, except for a significant increase for plants under NaCl?+?KCl two weeks after treatment. Our results indicated that stressed plants accumulated significantly more soluble sugars and amino acids in comparison with the control. Foliar sprays with KCl and CaCl₂ reversed the negative effects of salinity on plant biomass and induced the accumulations of compatible solutes. Moreover, concentrations of some essential oils and gallic acid increased in sprayed plants, but these effects were dependent on the type and duration of the treatment. Overall, spraying leaves with K⁺ and Ca²⁺ was able to mitigate salinity stress in Thymus vulgaris even during the recovery period.     

Evaluation of the carryover effect of antibiotic,bee pollen and propolis on growth performance,carcass traits and splenic and hepatic histology of growing rabbits

Sixty‐four nulliparous female rabbits were distributed among eight groups (eight animals/group). Group one was the unsupplemented control group; the other seven groups were supplemented with zinc bacitracin (ZnB) at 100 mg, or bee pollen (BP) and/or propolis (Pro) at 150 and 300 mg in a capsulated form, three times a week, day after day, continuously all over the experimental period. The experiment was run for eight parties; at each parity, 28 kids of each doe group (a total of 224 rabbits) were divided into two subgroups weaned, respectively, at 24 and 30 days of age. Thus, for each parity, there were 16 groups (eight does treatments × two weaning age, 14 rabbits per group). The growing rabbits fed the standard diets without supplements. The growth performance, the carcass traits, the liver and the spleen histology of rabbits were checked up to 90 days of age to find possible carryover effects of the supplements. The supplements had no significant effect on most of the growth performance at 90 days of age, but BP150 and BP+Pro300 increased the growth rate in comparison with ZnB group. The liver weight in the control, BP300 and Pro300 groups was higher than the ZnB one. The spleen weight was higher in the groups ZnB, BP150, Pro300 and BP+Pro300, followed by the control, BP300 and BP+Pro150 and thus Pro150. The heart % in the BP150 and Pro300 groups was higher than ZnB and BP+Pro150 groups. A lymphoid hyperplasia of splenic white pulp was observed in the BP+Pro groups, while propolis alone showed a mild activation of lymphobiosis. The Pro and BP groups showed the same picture of the control group exhibiting a hydropic degeneration of mostly hepatic cells, while the ZnB group exhibited adverse effect on the bile ducts featuring portal periductal inflammatory cells infiltration with epithelial hyperplasia reflecting chronic cholangitis.     

A real-time polymerase chain reaction assay for the detection of the myxozoan parasite Henneguya ictaluri in channel catfish

Proliferative gill disease (PGD), caused by the myxozoan parasite Henneguya ictaluri, is the most prevalent parasitic infection affecting commercial channel catfish (Ictalurus punctatus) aquaculture. There are currently no effective chemotherapeutic or biological control measures for PGD, which often peaks during the spring and fall when water temperatures are between 16-25 degrees C. The current diagnostic techniques of gross examination of gill clip wet mounts and histopathology are subject to false-negatives during the early stages of infection, and the quantifiable nature of end-point polymerase chain reaction (PCR) is subjective. Consequently, a rapid and more sensitive quantitative real-time PCR assay was developed for the detection of H. ictaluri during the early stages of infection in channel catfish. A 23 base-pair TaqMan probe was designed based on previously published H. ictaluri PCR protocols. The sensitivity of the assay was the equivalent of a single H. ictaluri actinospore, and in a pond challenge study, quantitative real-time PCR proved to be more sensitive than gross examination, microscopic examination of gill clip wet mounts, and histopathologic examination of gill tissue sections. Future applications of this assay will focus on developing methodologies to be used in conjunction with current pond-monitoring protocols to evaluate potential treatments and better manage this significant seasonal disease.     

Effects of Dietary Protein Levels on Gonad Maturation, Size and Age at First Maturity, Fecundity and Growth of Nile Tilapia

Six-week-old Nile tilapia (Oreochromis niloticus) fry with an average weight (SD) of 0.51(0.2) g were reared for 140 days on five formulated, isocaloric diets of different protein levels (25, 30, 40 and 45% by dry weight). Fish fed diets of higher protein levels (40 and 45%) showed better growth and feed conversion ratio than those on lower protein levels. Fast-growing fish matured earlier. Maturation rate was affected by the dietary protein levels. Males matured earlier than females: the first mature males were recorded when they were 14 weeks old, whereas the females matured after 18 weeks. In both sexes, mean percentage of mature fish rose with increasing dietary protein level, the percentage of mature males being higher than that of the females. Similarly, the percentage of mature fish rose with the increasing age of fish, with more than 50% males and females mature at the age of 22 and 24 weeks, respectively, the exception being the 25% protein diet fed fish, where the percentage of mature fish was below 50%. In all treatments, spawning was initiated when the fish were 22 weeks old. Smallest size at spawning of males and females was 9.2 cm (13.1 g) and 8.1 cm (8.9 g), respectively, and dietary protein levels influenced the size of fish at first maturity. For both sexes, no difference was found in the gonado-somatic index (GSI) among different treatments. Fecundity increased with increasing dietary protein levels, but significant differences were found only between 40–45% and 25–35% dietary protein levels. The relative fecundity (eggs g^–1 female) was higher at the lower dietary protein levels (25–35%) than at the higher dietary protein levels (40–45%). The dietary protein levels did not have any significant influence on the size and weight of mature eggs. The chemical composition of fish and mature ovaries was significantly influenced by the dietary protein level.