Prevention of Acoustic Trauma-Induced Hearing Loss by N-acetylcysteine Administration in Rabbits

Background: Acoustic trauma is an injury to the hearing mechanisms in the inner ear due to excessive noise. This injury is the most prevalent cause of sensorineural hearing loss in humans, especially from occupational exposure. Previous studies have shown the essential role of free radical formation in the inner ear hearing loss caused by acoustic trauma. Objectives: This study was performed to determine the effect of N-acetylcysteine (NAC) administration for reducing acute acoustic trauma in rabbits. Materials and Methods: Twenty four rabbits were assigned to four groups including: control, noise plus saline, noise plus NAC administration (325 mg/kg body weight by intraperitoneal injection (IP), three days before exposure to noise and three days after noise exposure), and NAC alone. Auditory brain stem response (ABR) threshold was measured before exposure and one hour and 14 days after exposure. Results: The saline plus noise group had on average a 49 decibel (dB) temporary threshold shift (TTS) and 23.9 dB permanent threshold shift (PTS) at the studied frequencies, while rabbits in the NAC administration plus noise group had a 31.5 dB TTS and 10.7 dB PTS averaged across the frequencies. Conclusions: Administration of NAC can provide appropriate protection against acoustic trauma-induced hearing loss in rabbits at all studied frequencies

Application of sodium alginate cover in frozen and cleaned common kilka and its quality evaluation by bacterial,chemical and sensory tests

This project was carried out to increase shelf life of kilka and prevent color changes during cold storage. Edible film made by sodium alginate (0.5% concentration) was used for fish packaging at time zero. The covered samples were kept at -18°C. Examination were carried out for a period of six months. Coliform, Escherichia coli and Pseudomonas bacteria contamination were negative until the end of storage period in the covered samples. Total bacterial counts and Acetaphylococcus bacteria count were lower in the treated samples (2.93 and 1.46log cfu/g, respectively) compared with the control specimens (3.21 and 2.28log cfu/g, respectively). Chemical factors consisting of humidity, protein, lipid, ash and calorie were higher in the treated samples (73.34%, 18.96%, 4.62%, 2.88% and 134. 63% kcal/kg, respectively) compared with the control samples (59.43%, 18.04%, 4.03%, 2.87% and 108.43% kcal/kg, respectively) and fresh fish samples (73.93%, 18.91%, 4.59%, 2.87% and 117.28% kcal/kg, respectively). Free fatty acids (0.77 and 9.21g/100), thiobarbitoric acid (0.001 and 0.15mg/kg), peroxide value (0.06 and 3.75meq/kg oil), TVN (6.92 and 16.28mg/100g) and pH (6.34 and 6.91) were lower in the treated samples compared with the control samples. However, no statistically significant decreases were observed in chemical factors including moisture, peroxide value, TVN and pH in the covered samples compared with the control samples during cold storage (P>0.05). According to the statistical analyses of sensory specifications including taste, odor, color, tissue and total acceptance, there was a significant difference between the covered samples and the control ones (P<0.05). Using the results of bacterial, chemical and sensory tests and statistical analyses, the covered samples had a favorable quality until the end of storage period. Also, based on the results of sensory analyses and moisture test, the control samples had a favorable quality for a period of three months

Rate (ROI) and severity (SOI) of infection of white spot disease in cultured and captured Penaeid shrimps in the Persian Gulf using histopathology and polymerase chain reaction

White Spot Disease (WSD) is well known as a widespread viral disease in shrimps from 1992. Many studies focused on morphological, histopathological and epidemiological characteristic and pathogenecity of the disease but less on the determination of the severity of WSD using the histopathological features in target tissues. A generalized scheme for assigning a numerical qualitative value to severity grade of infection considering to histopathology and counting the inclusion bodies in different level of infection and different microscopic fielding immersion lens was accomplished before. This study was conducted in order to estimate the rate of infection (ROI) and the severity of infection (SOI) of WSD in native shrimps in the Persian Gulf. About 90 live specimens of affected cultured Penaeus indicus were collected from Abadan region, south Iran and 150 specimens of native shrimps were captured from the Persian Gulf. Histopathological changes were observed by light microscope in target organs such as: gills, cuticular epidermis, heart, hemolymph, fore stomach and hepatopancreas. ROI and SOI were estimated respectively by standard formulas and grading between 0-4 based on the percentage of white spot syndrome virus WSSV positive cells in selected fields of microscope. The results were confirmed by conducting nested PCR method. The SOI of Parapenaeopsis stylifera was estimated in grade four and its ROI was about 85% as the most susceptible species. Histopathologic infection of Metapenaeus affinis shrimp by WSD was observed also during this stud

Comparison of effect of Zataria multiflora and Rosemarinus officinalis extracts on quality of minced frozen silver carp

The aim of the this study was to have a comparison between Zataria multiflora and Rosemarinus officinalis extracts on quality of minced frozen silver carp preserved in cold storage temperature -18°C for six months. In this research, one control and three treatments of minced silver carp were prepared as Tr1 (+ Zataria), Tr2 (+Rosemary) and Tr3 (mixed with Rosemary and Zataria) all in normal packaging. After quick freezing of samples in the spiral freezer they were preserved in cold storage temperature -18°C for six months. In this period, the changes of Peroxide Value, Total Volatile Nitrogen, Tio Barbituric Acid and Free Fatty Acids in all treatments were measured based on a predetermined schedule. The results of this investigation showed a significant effect of anti-oxidant in all treatments (p<.05) and it was concluded that Rosemary containing anti-oxidants maintains the best quality after six months of cold storage and corruption indices are not exceeded. Analysis of Peroxide Value, Total Volatile Nitrogen, Tio Barbituric Acid and Free Fatty Acids in different treatments during six months of reservation in freezing under the temperature of -18°C showed that the obtained results to the end of the reservation period for all treatments has increased and treatment containing Rosemary, with Peroxide Value 6.83±0.35meq.1000g^-1, Tio Barbituric Acid 2.1±0.1mgMAL.kg^-1 and Total Volatile Nitrogen with 19.16±0.28mg.100g ^-1 had the best quality of preservation compared with other treatments during the preservation period. Therefore, based on these results and statistical analyses, the effect of anti-oxidant and time in all treatments is significant (p<.05) and the treatments containing Rosemary had the best quality preservation status in -18°C and did not surpass perishing criteria during this period

Optimization of morphology and geometry of encapsulated Hypophthalmichthys molitrix oil

In the present study, the effect of stirring speed and the type of cross linking agent on the size and formation of microencapsulated Silver carp (Hypophthalmichthys molitrix) oil were investigated. The gelatin/gum Arabic was used for encapsulating and the capsules were prepared by complex coacervation. Microcapsules were analyzed by optical microscopy technique and particle size analyzer. Results suggested the use of glutaraldehyde as the cross-linking agent instead of formaldehyde can caused the Microcapsules become spherical shape, smooth surface with no obvious dents and narrower particle size distribution. The average particle sizes were 537.2±0.8 μm, 84.4±0.5 μm, 12.98±0.4 μm, 8.24±0.5 μm, and 4±0.7 μm at the homogenization stirring speed of 100, 300, 500, 750 and 1000 rpm respectively. The best conditions of experiment were with 25% glutaraldehyde at 1000 rpm of stirring speed

Evaluation of some biofilter substrates in freshwater recirculation system

The nitrifying bacteria acting on various biofilter substrates including: scoria, P.V.C., marble and zeolite were evaluated. The experiment started with manufacture of a recirculation system with 130 liter fresh water volume in 7 l.min-1 flow rate in 3 replicate for every treatment. The volume of each biofilter was 60×40×30cm and after achievement to stable environmental conditions the nitrifying bacteria at a concentration of 105 ml-1were inoculated in each biofilters. Daily 3-10mg.l-1 of NH4Cl was added to biofilters. The procedure was conducted by exposure of Ammonium and Nitrate concentrations and pH in biofilters. The results showed that the Scoria can be reliable substrate as biofilter, in which provide the best substrate for the growth and attachment of the nitrifying bacteria which can reduce the retention time of a biofilter from 40-60 to 15 days

Effects of fish meal replacement by silkworm pupae on growth, survival and body chemical composition of rainbow trout (Oncorhynchus mykiss)

Silkworm pupae meal is a non-conventional animal protein feedstuff. It is the by-product after the silk thread has been wound off from the cocoon. To investigate the effects of animal protein on growth and survival of rainbow trout (Oncorhynchus mykiss), a sixty-day feeding experiment was conducted. Four replacement levels (0, 5, 10 and 15 percent) of silkworm pupae meal were compared using a completely random design. We used 360 juvenile rainbow trout (average weight 55±3.42g) divided into 4 groups and 3 replications, each containing 30 trout for 60 days. Sampling for nutritional effects was carried out every 10 days and at the end of the experiment, weight gain, feed conversion ratio, specific growth rate, protein and efficiency ratio were compared which showed no significant differences (P>0.05) among the treatments. Total length and survival rate were not significantly affected in the treatment groups. The highest percentage of carcass protein and the lowest percentage of carcass fat belonged to the control treatment. Our findings showed that silkworm pupae meal could replace 15% of fish meal diet in rainbow trout culture

Effect of whey protein coating on physico-chemical properties of gutted Kilka during frozen storage

The a im of th is paper was to study the effects w hey pro t e in c oat i ng on ch e m ic al a nd physic al properties of gut t ed K i l ka dur i ng f roz en stor a ge. Coating of Kilka has done by dipping in whey protein solution with different concentrations of 3, 7, 10 and 13%, for 1h. Then, after being packed in polyethylene dishes, they were covered in cellophane blanket and stored in -18°C. There were 125 testing and control packages, each of them weight 250grams. Heme iron, peroxide value, protein, lipid and pH has measured after 0, 1, 2, 3 and 4 months storage in freezer. R e s u l ts of h e me iron, p e roxi de v a l ue and lipid of control tr e at m ents h a ve s hown s i gni f icant difference among ex p e r i m ent al tr e at m ents (p0.05). Our results showed that coating process with di ff e r e nt whey pro t e in con c entrat i on leads to decrease in peroxide value and increases the iron content. 13% whey protein concentration was provided the most satisfactory results

Ultrastructural and pathogenesis of Monodon baculovirus in SPF shrimp, Litopenaeus vannamei imported to Iran

Viral pathogens are major causes of outbreaks in shrimp farms throughout the world. Monodon baculovirus has been known to be invasive in 85-100% of the shrimp hatcheries, in early or late stages of shrimp. Three-hundred and sixty juvenile of Litopenaeus vannamei with average (±SD) size of 7.99±0.54 g and 3600 post larvae 10-15 were prepared from Shrimp Research Station located in Helleh and 3 hatcheries from Bushehr Province, southern part of Iran, respectively. They were allocated to 9 glass aquariums (50×50×60cm) as 2 groups (postlarvae and juvenile), controls with 3 replications using 100 liters well aerated water. They were exposed to MBV as water-born path. Concerning the pathogenesis, three phases were observed. The quantity of intranuclear occlusion bodies was 1-9. Mortality was only observed in postlarvae but not in adult or control groups. It is concluded that MBV can be an invasive pathogen for SPF offspring or postlarvae of L. vannamei being imported to Iran