فصلنامه دامپزشکی ایران
سال نوزدهم شماره 79 (تابستان 1402)

The aim of this study was to investigate the effects of sublethal concentrations of silver nitrate on changes in biomarkers of oxidative stress (superoxide dismutase, catalase, glutathione, total antioxidant capacity and malondialdehyde), in the hepatopancreas of white leg shrimp (Litopenaeus vannamei). For this purpose, whiteleg shrimp (Litopenaeus vannamei) post larvae shrimp were exposed to sublethal silver nitrate concentrations (equivalent to 10 % (treatment 1), 25 % (treatment 2), 50 % (treatment 3) and 75 % (treatment 4) LC50 AgNO3) for 21 days. Catalase, glutathione and total antioxidant capacity in treatments 3 and 4 compared to control treatment had a significant decrease while malondialdehyde increased significantly. Also, superoxide dismutase activity in both treatments 3 and 4, total antioxidant capacity decreased significantly only in treatment 4 compared to the control group, but malondialdehyde activity in treatment 4 increased significantly. The results of this study showed that exposure to concentrations of 0.042 and 0.063 mg/L of silver nitrate caused oxidative damage to hepatopancreas tissue of white leg shrimp (Litopenaeus vannamei).

Today, respiratory diseases are one of the most common problems in animals and humans. One of the methods to control respiratory diseases is the use of bronchodilator drugs such as salbutamol and formoterol. The aim of the present study was to compare the effect of salbutamol and formoterol on electrocardiogram, blood pressure, potassium and glucose changes in dogs. For this purpose, fifteen male adult dogs were used. After a health check, animals were divided into three groups: control, salbutamol and formoterol. Treatment groups were inhaled daily with a single dose of one puff twice daily (morning and night) for 7 days. Finally, 4 hours after the last administration, electrocardiogram, blood pressure and arterial oxygen saturation were measured. Then, blood samples were taken from cephalic vein (5 ml) to measure blood potassium and glucose levels. Results showed that Administration of salbutamol caused a significant decrease in systolic and diastolic blood pressure, while formoterol caused a significant increase in blood pressure. Salbutamol and formoterol significantly increased heart rate. Blood potassium level as well as RR interval in electrocardiogram were significantly reduced in the groups treated with both drugs compared with the control group. The group treated with salbutamol showed a significant increase in blood glucose compared with the control group. According to the results, administration of salbutamol and formoterol reduced potassium unlike glucose. Salbutamol also was more effective than formotrol on cardiac effects and arrhythmogenic potential. Therefore, the administration of salbutamol and formoterol in cardiac or diabetic patients should be treated with caution and control.

Ticks are parasitic and bloodthirsty arthropods. Different species of ticks are important carriers of animal and human pathogens. Accurate identification and diagnosis as well as their continuous monitoring can be effective in reducing animal diseases, especially in the transmission of some protozoa. As an efficient tool in morphological studies and accurate identification of ticks electron microscopy is very useful. In the present study, using this tool, accurate identification of ticks collected from Khuzestan and Mazandaran regions in 4 consecutive seasons has been done. From a total of 6954 ticks collected from the body surface of cattle, sheep and goats in the two mentioned provinces, 13 species were detected. They include: Rhipicephalus turanicus, Rhipicephalus sanguineus, Rhipicephalus (boophilus) annulatus, Rhipicephalus bursa. Hyalomma anatolicum anatolicum, Hyalomma asiaticum asiaticum Hyalomma excavatum, Hyalomma marginatum, Dermacentor marginatus, Haemaphysalis parva, Haemaphysalis punctate, Haemaphysalis inermis and ixodes ricinus. Based on the results, Factors such as temperature and sampling season are directly related to the isolated ticks. The results of the present study showed that the frequency ratio of Rhipicephalus ticks in different seasons in Khuzestan and Mazandaran provinces has followed a relatively similar pattern.

The cichlidae family has more than 1300 species which in turn have great species morphologic differences. In this study, histology of liver, spleen and pancreas of four cichlid species (green terror cichlid, Oscar, giraffe cichlid and Texas cichlid) were compared. For this purpose, four apparently normal fish specimens from each species were selected after killing of which, tissue samples were taken. The sections stained with two methods (Haematoxillin- Eosin and Periodic acid Schiff). The results showed that all liver sections contained pancreas tissues around the liver blood vessels. Liver cells size in two species (green terror cichlid and giraffe cichlid) was significantly bigger than the two other species. The liver cell to pancreatic cell ratios also was significantly higher in two species. The liver size in giraffe cichlid, was even significantly bigger than the green terror cichlid. Exocrine pancreatic cell size in all 4 species showed no significant difference. The spleen in four fish species showed different degrees of amount and intensity in melanomacrophage centers. In PAS stained sections, only the pancreatic tissues showed more PAS positive reaction that may be due to the more glycogen content. The liver showed a weak PAS reaction. The bigger size formation of liver cells in two species can be due to feeding regime or simply a species specific trait. Yet more investigation is still needed to determine the importance of these findings.

Ornithobacterium rhinotracheale (ORT) is a newly emerging respiratory bacterial pathogen that causes significant economic losses to the poultry industry. Previous studies in Iran have shown high molecular and genetic similarity among ORT isolates by SDS-PAGE, ERIC-PCR and 16SrRNA gene sequencing during 1999-2009. The aim of this study was the genotyping of ORT isolates recovered from commercial chickens by using RAPD-PCR with OPG11 primer and multilocus sequence typing (MLST). In total, 30 ORT isolates recovered from commercial chickens of Iran during 2000-2017 and confirmed by bacteriological, biochemical and PCR tests were used in this study. All 30 ORT isolates were subjected to RAPD-PCR with OPG11 primer. For MLST, 5 isolates were selected based on their RAPD patterns. Seven primer pairs were synthesized for amplification and sequenceing of seven housekeeping genes of adk, aroE, fumC, gdhA, mdh, pgi and pmi in MLST assay. In RAPD-PCR with OPG11 primer, 9 different genotypes were found. The DNA sequences of the distinct alleles of these seven loci of 5 ORT strains were compared with other alleles deposited in GenBank. Four out of 5 strains belonged to sequence type 9 (ST9) and one strain was found to be a new ST.  Based on the results of the present study, a new sequence type among ORT isolates of Iran was found that has not been previously reported from elsewhere in the world. Further studies on more ORT isolates may help in identification of different sequence types and dominat ST in the country.

Newcastle disease (ND) is one of the important viral diseases of poultry that causes considerable economic loss to breeding farms. Continuous evaluation of circulating virus genotypes and pathotypes is the crucial step to control the disease prevalence. The present study aimed to study the phylogenetic and pathogenicity indices of circulating ND virus (NDV) in poultry farms located in Mazandaran province during 2018. Following the isolation of the virus from the brains of the dead chickens in five different farms, intracerebral pathogenicity index (ICPI) and the mean death time (MDT) were determined. For phylogenetic analysis, virus RNA was extracted and following RT-PCR, the sequence of the F gene was determined and compared with those presented in the gene bank. Results showed that the isolated viruses had ICPT of 1.97 and MDT of 56 hours, related to the velogenic pathotype and their virulence was close to the standard strains of challenge viruses. Also, based on the results of phylogenetic analysis, the isolated viruses were classified as genotype VII. By determination of phenotypic and genothipic identity of the isolated viruses, the clinical evidence showing the velogenic and visceral form of ND was confirmed. The present study showed that the NDV causing mortality in commercial poultry farms during 2018 had virulence near to standard challenge strains and belonged to VII genotype and VII.1.1 subgenotype of NDV. Therefore, the isolated virus, as a local virulent strain, could be used in challenge tests and evaluation of the preventive vaccination programs.

Trichomoniosis is caused by the obligatory parasite, Tritrichomonas foetus in cats. This protozoan causes some gastrointestinal symptoms such as colitis, semi-formed to liquid diarrhea, and sometimes fresh bloody or mucoid feces, bloating, and bowel incontinence in the infected cats. The present study aimed to diagnose the Tritrichomonas foetus in cats in Ahvaz city by direct smear and culture methods in the Dorset medium. After observation of motile trichomonads, polymerase chain reaction (PCR) is a diagnostic technique carried out to confirm the organism. In the present study, fecal sampling was taken from 100 cats directly using swap. In wet smear, the motile flagellates that were similar in size to T. foetus by rolling motion’ were identified. Positive samples were cultured in the Dorset medium. A portion of the culture medium was used for extracting genomic DNA followed by nested-PCR assay with two pair primers. The molecular findings showed that 18% of the cats (positive cases) were infected with Tritrichomonas foetus. The cats with diarrhetic history had the most infection rate with 83/3% and 66/66%, respectively. Also, the rate of infection in cats less than one year was 14% and more than the cats of more than one year (4%) significantly. PCR assay was useful in differentiating between T. foetus and another trichomonad observed in fecal samples of the cats.

The aim of this study was to compare the effects of Two drug combinations of Torsemide-Enalapril-Digoxin and Furosemide-Enalapril-Digoxin on the cardiovascular system in the treated dogs. For this purpose, five 1.5-year-old mixed breed dogs were selected to undergo echocardiography at three times (The first time as the control group, the second time as the first group and the third time as the second group). No drugs were used in the control group. In the first group, 2.5 mg/kg of furosemide, 0.5 mg/kg of enalapril and 3 µg/kg of digoxin and in the second group, 0.3 mg/kg of Torsemide, 0.5 mg/kg of enalapril and 3 µg/kg of digoxin were administered orally. Echocardiography of the dogs was done after one hour of drug administration. Measured echocardiographic parameters included: Left ventricular size during systole, left ventricular size during diastole, heart rate and fractional shortening. The results of each group were evaluated using chi square analysis method. The results of this study showed that changes in heart rate and left the ventricular size changes during diastole were not significant between the control and other groups. Although left ventricular size during systole was significantly lower in the torsemide-enalapril-digoxin group than the other groups, in this study, it was found that the fractional shortening changes in the group receiving torsemide-enalapril-digoxin were significantly higher than the other two groups. The results of this study indicate better effects of torsemide than furosemide in improving heart function and increasing short fractional shortening, but both drugs have similar effects on other cardiac parameters.

Leptospirosis as a zoonotic disease, is characterized by fever, jaundice, abortion and hemoglobinuria. It is widespread and the determination of the dominant serotype in the animal species of each region accelerates the control and prevention program. The 862 blood samples were colected from cows (Holstein and Simmentals), buffaloes, sheep, goats, horses and mules.  Sera were examined by microscopic agglutination test (MAT) with six live serotypes. The overall prevalence was 19.54%, with the highest (37%) and the lowest (6.6%) in Holsteins and mules, respectively. Meanwhile, 25.4% of buffaloes, 19.3% of sheep, 13.7% of Simmental, 19.2% of goats, and 12.3% of horses were positive. The highest and lowest frequency was for pomona and canicula, respectively. In all studied species prevalence of infection in male was higher that in female but not significant. In ruminants, the prevalence of infection increased with age. In conclusion, leptosiral infection in ruminants was higher than in equidae and in ruminants, Holstein cattle was higher than the others, therefore vaccination in Holstein cattle is necessary to prevent the more infection in animals and also in human heings.

Coccidiosis is an economically important disease caused by a variety of Eimeria spp. In this study, the frequency of Eimeria species in sheep and goats of Urmia city in different seasons of the year was investigated. For this purpose, 280 sheep and goats were studied from Februry 2020 to Februry 2021. Fecal culture method with potassium bicromate (2%) was performed for Identification of Eimeria spp. Out of 280 small ruminants studied, 48 (17.14%) were infected with Eimeria spp. From the studied sheeps, six Eimeria species including E. intricata (40.54%), E. parva (18.91%), E. faurei (16.21%), E. ovina (10.81%), E. ahsata (8.10%), and E. pallida (5.4%) were identified. From the studied goats, three Eimeria species including E. arloingi (54.54%), E. christenseni (27.27%) and E. palida (18.18%) were also identified. The results of this study showed that there are different types of Eimeria spp., including pathogenic Eimeria in sheep and goats in Urmia. According to the importance of sheep and goat breeding industry in the northwest of Iran, preventive and periodic treatments against coccidiosis can prevent the effects of this parasite, including reduced production and growth rate especially in younger species and thus help the economics of the region.

Bartonella species are lesser-known pathogenic bacteria that infect a wide range of domestic and wild animals as well as humans. Currently, out of 40 Bartonella species/subspecies, at least 17 are associated with clinical signs in humans and animals. However, despite the zoonotic importance of bartonellosis, there is limited information about prevalence and species infecting dogs and cats in Iran. The aim of this study was molecular identification of Bartonella species in dogs and arthropods infesting them in Hamedan and Kermanshah cities in the west of Iran. Blood genomic DNA (gDNA) was extracted from 100 dogs (45 from Hamedan and 55 from Kermanshah) and, of 25 Ctenocphalides canis fleas, six Pulex irritans fleas and 12 Rhipecephalus sanguineus ticks collected from nine infested dogs were examined for the presence of Bartonella species. Conventional PCR targeting fragments of ITS and rpoB genes was performed, and PCR-positive samples were sequenced bidirectionally and analyzed phylogenetically. Out of 100 dogs, 14 dogs (14%, ten from Hamedan and four from Kermanshah) were found infected with Bartonella species. Nucleotide sequencing confirmed the presence of four Bartonella species in the examined population i.e. Bartonella vinsonii subsp. berkhoffii and Candidatus B. merieuxii in dogs. None of the examined fleas scored positive but one Rh. sanguineus tick from a blood-negative dog was infected with Bartonella DNA. Results of the present study showed the presence of different zoonotic Bartonella species in dogs of Hamedan and Kermanshah cities highlighting the importance of this vector-borne infection. Effective ectoparasite control strategies, regular examination of pet and urban dogs and cats and successful chemoprophylaxis are suggested.

The objective of this study was to compare two estrus induction protocols in Shal ewes (Iranian native breed) during the non-breeding season using progesterone injections and an intravaginal sponge. Non pregnant ewes (n=180), considering their age and BCS were stratified randomly into two groups: progesterone injection (n=54; age: 33.0±3.21 months; BCS, 2.5±0.11) and vaginal sponge (n: 54; age: 37.5±3.58; BCS: 2.6±0.11). The progesterone injection group received four consecutive injections of progesterone (50 mg, SC), 3 days apart. Ewes in the sponge group received an intravaginal sponge (40 mg Flugestone acetate) for 14 days. An intramuscular injection of eCG (300 IU) was given concurrent with sponge withdrawal or 48 hrs after the last progesterone injection. Twelve hours after eCG, estrus was detected by rams equipped with harnesses. Laparoscopic AI was performed 50-56 hrs after eCG injection by fresh semen (100×106 sperm in 0.2 ml per uterine horn). Pregnancy was diagnosed by rectal ultrasonography, 35 days after insemination. The incidence of estrus (74.1%) was greater in the sponge group than injection group (38.9%). There were no differences between the two groups in terms of time to estrus and time to AI after eCG injection. There was no differences between the two groups in the interval from estrus to AI, fertility, prolificacy, and fecundity. Fertility was greater in ewes that were inseminated within 24 hrs after estrous detection in the progesterone injected group (76.2%) compared to the sponge group (42.5%). In summary, due to the similarity in fecundity, as the final indicator of reproductive performance, and less cost, availability and no intervention of reproductive tract, progesterone injection method could be advised for inducing estrus in ewes during the non-breeding season.

Today, oak fruit as a food ingredient is identified as a substitute for corn in the poultry industry. However, this fruit contains significant amounts of phenolic compounds, such as tannins, which limits its use in poultry diets. Generally, food ingredients containing phenolic compounds can affect the expression of genes in the immune system. Therefore, the aim of this study was to investigate the effect of different levels of oak acorn on the expression of interleukin-5 (IL-5) and interleukin-6 (IL-6) genes in the bursa Fabricius tissue of broiler chickens. In this study, three diets containing zero, 15% and 20% oak fruits were used to feed broiler chicks in a 42-day period. Total RNA were extracted from bursa Fabricius tissue of 6 chickens for each treatment (18 broiler chickens) on day 42. The expression levels of IL-5 and IL-6 genes were normalized with β-actin gene as a reference gene. To analyze the gene expression data, REST, 2009, V2.0.13 software was used.  The results of this study showed that expression of IL-6 gene in bursa Fabricius was not significantly different between treatments at day 42 although its expression in the treatment of 20% of oak acorn was decreasing. The expression of IL-5 gene in bursa Fabricius was significantly decreased in 15% and 20% oak acorn treatments compared to control group.  Generally, replacing 15 to 20% of dietary corn with oak acorn can reduce the expression of immune system genes in the tissue of the Bursa Fabricius in broilers due to increased phenolic compounds in the diet. Therefore, it is recommended that lower levels of oak acorn be used in diet of broiler chickens.

The Newcastle disease virus (NDV) causes infection in a wide range of birds and is considered a global threat to the poultry industry worldwide. To isolate and identify the molecular NDV, trachea and caecal tonsil samples were collected from dead birds suspected to Newcastle disease from 15 vaccinated broiler breeder flocks in Mazandaran province during 2020 to 2021.The tissue samples after preparation were inoculated into 9-day-old embryonated chicken eggs. The RT-PCR reaction was performed to detect the F gene of NDV on allantoic fluids. The PCR products of 3 isolates were sequenced, and a phylogenetic tree was drawn. The results of comparing the amino and nucleotide sequences of partial F gene isolates obtained from Mazandaran province showed that genotype VIId   is circulating in broiler breeder farms and is 99 to 96% similar to previous reported isolates in Iran. It was concluded that the isolation of VIId genotype from vaccinated broiler breeder flocks during the production period means that the present vaccination program could not successfully prevent Newcastle diseases in breeder farm and it is a necessary type of vaccine and changed vaccination program.

Equine Herpesvirus type 1 is a DNA virus with worldwide distribution which can cause noticeable economic loss. Although this virus is moderately contagious, after shedding, latent infection in the host can be considered as a potential risk for the other horses in the herd. The most important clinical syndromes caused by this virus are respiratory involvment, abortion, myeloencephalopathy and neonatal disease. The current study, using a PCR test on 150 horses in five cities in Khuzestan province (Ahvaz, Shooshtar, Shoosh, Ramhormoz and Mahshahr), reported no positive case about the presence of a DNA virus in the blood of the studied horses. This finding has shown that the presence of this virus in the horses from this region, at the time of performing the test, is justifiable. The results of this study vis-à-vis those of other studies show that the presence of EHV-1 among horses in different studies is very dissimilar. Regardless of the difference between the actual infection rate in different regions and herds, the reason for this disparity is possibly related to the sample type, presence or absence of clinical signs (related to the virus) in the sampled horse, and the laboratory method used.

Arsenic trioxide (ATO) is used in treatment of acute promyelocytic leukemia (APL). One of the major side effects of this drug is liver toxicity. Different doses of this drug have been used in different studies. Based on the ATO treatment protocol in APL patients (0.15 mg / kg) and the dose conversion formula between humans and laboratory animals introduced by the FDA, a dose of 1 mg / kg was selected. Royal jelly has attracted increasing attention in recent years given its high antioxidants capacity. This study aimed to evaluate the effect of royal jelly on histopathologic and biochemical changes of liver based on arsenic trioxide-induced hepatotoxicity in 8 groups of 5 rats. In groups one, two and three respectively, normal saline, royal jelly and arsenic trioxide; in groups four, five and six, different doses of royal jelly along with fixed dose of arsenic trioxide; in group seven arsenic trioxide along with vitamin E; in group eight arsenic trioxide alonge with vitamin E and royal jelly were given orally for 30 days. According to the results, the liver was normal in the normal salin group and royal jelly receiving groups, while it had pathological changes as hyperemia and cellular swelling (reversible changes) in other groups. The severity of these changes was reduced in royal jelly receiving groups. There was no significant change in the liver enzymes activity in all study groups.

Enterococci are a part of the opportunistic pathogens, which are very important in medicine. These bacteria can cause a variety of diseases in both dogs and human. The aim of the present study was to investigate the frequency detection of Enterococcus faecalis and Enterococcus faecium in companion dogs in Ahvaz and review of risk factors including age, gender, breed and diarrheic status in animals. Also, the prevalence of virulence genes was evaluated including gelatinase (gelE) and (ccf) and antibiotic susceptibility measured in obtained samples. Sampling was performed from the rectum of the 150 dogs (36 cases diarrheic and 114 non-diarrheic). The samples were evaluated by two methods of bacterial culture and PCR. In bacterial culture, 122 isolates, suspected to Enterococcus species, were isolated and subsequently the detection of SodA gene specific to Enterococcus faecalis and Enterococcus faecium was performed by PCR. Overall forty-five positive isolates were identified, which thirty four of which were Enterococcus faecalis (75.5%) and 11 were Enterococcus faecium (24.5 %). In regard to identify virulence genes (gelE and ccf), 36 out of 45 isolates were positive for virulence genes. Twenty six isolates (57.77%) had virulence genes, 5 isolates (11.11%) ccf gene and 5 other isolates (11.11%) gelE gene. In all, nine isolates (20%) had no virulence gene. Fourteen different antibiotics were used to determine antibiotic susceptibility that indicated all isolates were resistant to azithromycin, streptomycin, ampicillin and imipenem. Thereafter, the highest resistance was related to erythromycin and cephalexin (95.5%), trimethoprim sulfamethoxazole (84.4%) and gentamicin (80%), respectively. Also, the highest sensitivity was related to nitrofurantoin (62.2%), penicillin G (60%) and enrofloxacin (55.5%), respectively. There was no significant relationship between risk factors such as age, gender, breed and diarrheic condition with the presence of Enterococcus in the studied dogs (P>0.05). The results showed that the prevalence of Enterococci was relatively significant (30%) in dogs of Ahvaz district. Antibiotic resistance was significant in the two species of Enterococci. Finally, because of the very high importance of antibiotic resistance, appropriate administration of antibiotics is recommended.

Many cellular changes have been reported to play a role in the aging process of oocyte; however, few studies have been performed on the appropriate time and temperature for the storage. The main problem is the distance and time available for the transfer of oocytes to the laboratory, and protection of immature oocytes without reducing their ability to fertilize in vitro is very critical. The aim of this study was to compare the Embryo Holding (EH-Syngro) and HTCM-199 medium to store immature oocytes at room temperature without incubation. A total of 5268 oocytes were tested. The oocytes were stored at three temperature degrees including 4, 22 and 38 ° C for 6, 12, 18, and 24 hours.  After spending the storage time, they were entered to the standard maturation environment and finally IVF was performed.There was no statistically significant difference between the experimental and control groups  in terms of blastocyst production  at storage of 6h. At 12 hours, oocyte maturation and blastocyst production in all groups were significantly lower than that of the standard group. EHT and HTCM-199 medium in our experiment showed that they can be useful for storing immature oocyte for up to 6 hours at room temperature and have no adverse effect on maturation of oocyte and blastocyst production, and most importantly do not need an incubator to transport the oocytes to the laboratory.

Although there is not any report of the outbreak of Babesia bigemina in south, southeast and central regions of Iran, some clinical evidences of Texas Cattle Fever were observed in some native cattle in Sistan region, southeast of Iran. We conducted the present study to morpho-molecular identification of Babesia bigemina, to find the tick-vector and evaluation of clinical symptoms in the affected cattle. In spring 2018, the presence of Babesia bigemina piroplasm was evaluated in the blood specimens of 17 cattle that have been diagnosed with high fever, hemoglobinuria and severe anemia with Giemsa staining method. The collected ticks from affected cattle have been identified morphologically. The clinical symptoms were analyzed and treatment was performed with imidocarb dipropionate. The PCR procedure amplified the Babesia bigemina specific fragment of ITS1-5.8S-ribosomal DNA in blood specimens and tick salivary glands. The morpho-molecular investigations showed Babesia bigemina piroplasm in the blood of 8 numbers of investigated cattle. Also, the ITS1-5.8S-ribosomal DNA of Babesia bigemina was detected in the salivary glands of Rhipicephalus annulatus collected ticks. The clinical disorders of the disease have been treated after administration of Imidocarb dipropionate. The findings of the present study illustrate a new focus of Texas Cattle Fever and its vector in Sistan region, southeast of Iran.

The aim of this study was to investigate the effects of sublethal concentrations of silver nitrate on changes in biomarkers of oxidative stress (superoxide dismutase, catalase, glutathione, total antioxidant capacity and malondialdehyde), in the hepatopancreas of white leg shrimp (Litopenaeus vannamei). For this purpose, whiteleg shrimp (Litopenaeus vannamei) post larvae shrimp were exposed to sublethal silver nitrate concentrations (equivalent to 10 % (treatment 1), 25 % (treatment 2), 50 % (treatment 3) and 75 % (treatment 4) LC50 AgNO3) for 21 days. Catalase, glutathione and total antioxidant capacity in treatments 3 and 4 compared to control treatment had a significant decrease while malondialdehyde increased significantly. Also, superoxide dismutase activity in both treatments 3 and 4, total antioxidant capacity decreased significantly only in treatment 4 compared to the control group, but malondialdehyde activity in treatment 4 increased significantly. The results of this study showed that exposure to concentrations of 0.042 and 0.063 mg/L of silver nitrate caused oxidative damage to hepatopancreas tissue of white leg shrimp (Litopenaeus vannamei).