Background: Swine pasteurellosis, caused by Pasteurella multocida capsular types A and D, causes heavy economic loss to the pig farmers. The vaccine presently used is a bacterin of Pasteurella multocida capsular type B that is proven to be effective against bovine pasteurellosis. However, its efficacy against swine pasteurellosis is questionable. Methods: The present study was carried out to evaluate the efficacy of calcium phosphate nanoparticle adjuvanted bivalent subunit vaccine prepared from Pasteurella multocida capsular types A and D along with a monovalent subunit vaccine prepared from Pasteurella multocida capsular type B in mice. The Alum precipitated bacterin vaccine was used as the control. Result: The bivalent subunit vaccine showed significantly higher serum IgG response than either of the other two vaccines. The calcium phosphate nanoparticle adjuvanted vaccines could elicit 100% protection in mice against homologous challenges but the aluminum hydroxide adjuvanted bacterin vaccine could not elicit significant protection. Based on this preliminary work, it was concluded that the bivalent subunit vaccine would be a better option for immunization of swine against swine pasteurellosis.

Background: Multidrug resistant strains of Escherichia coli have been causing worldwide outbreaks of food borne diseases in recent years. The emergence of antibiotic-resistant strains of E. coli and the occurrence of transmissible drug resistance among the organism has amplified the complications associated with its control and treatment measures. Data associated with the prevalence, virulence factors and antimicrobial susceptibility of E. coli isolates are needed to be studied in order to develop an effective control strategy for colibacillosis in piggeries. The goal of the investigation was to study the antimicrobial susceptibility pattern and pathotyping of E. coli isolates from diarrhoeic piglets. Methods: 102 rectal swab samples were collected from diarrhoeic piglets of ICAR-AICRP/MSP on Pig, College of Veterinary Science, Assam Agricultural University, Khanapara, ICAR-National Research Centre on Pig, Rani, Guwahati, Assam and from different unorganized farms of the state. These samples were then inoculated in Luria Bertani (LB) broth and incubated aerobically at 37oC for 24 hours followed by sub culturing them in MacConkey’s lactose agar (MLA) and Eosin Methylene Blue (EMB) agar for purification of the suspected E. coli isolates. The isolates were characterized by biochemical tests and motility tests and were pathotyped based on detection of specific virulence genes by multiplex Polymerase Chain Reaction (PCR). Result: Out of 102 rectal swab samples examined, 92 (90.2%) yielded E. coli which included 41 (91.12%) of 45 samples collected from ICAR-AICRP/MSP on Pig, College of Veterinary Science, Assam Agricultural University, Khanapara and 32 (88.89%) of 36 samples from ICAR-National Research Centre on Pig, Rani, Guwahati, Assam and 19 (90.48%) of 21 samples from different unorganized farms. All the 92 E. coli isolates were examined for the presence of stx1, est1, elt1 and eaeA genes using specific primers. Among these isolates, 25 (27.17%) were positive for stx1 gene, 18(19.56%) for est1 gene, 6(6.52%) for elt1 gene, 3 (3.26%) for both genes est1 and elt1 and 12 (13.04%) for eaeA gene. Antimicrobial susceptibility pattern of the isolates revealed that the highest percentage (71.74%) of the isolates were resistant to tetracycline and the least (4.34%) to imipenem.

Newcastle disease (ND) is a devastating viral disease affecting poultry and has a substantial economic impact associated with high morbidity and mortality rates. Effective control measures rely on biosecurity measures and vaccination. However, use of phylogenetically divergent, thermolabile vaccines remains a major constraint for controlling ND outbreaks despite vaccination. To address the gap, the present study was undertaken to assess the thermostability profile of mesogenic (Genotype XIII) Newcastle disease virus (NDV) isolates with the aim of identifying heat-stable strains circulating in Assam, India. Five NDV isolates were assessed for thermostability by subjecting them to a range of temperatures at different time intervals. Among the isolates, AS/KM/18/32 exhibited the highest thermal stability, retaining HA (log2) titer and infectivity (log EID50) at 56 °C for 30 min, with a half-life of 19.99 min and an inactivation rate constant of -0.0348 min-1. In conclusion, mesogenic NDV (Genotype XIII) isolates circulating in Assam exhibit variable thermostability, warranting further studies on their biological pathogenicity and immunogenicity with a view to developing genotype-matched thermostable vaccine candidates.

Objectives: Detection of borderline oxacillin-resistant Staphylococcus aureus (BORSA) and modified Staphylococcus aureus (MODSA) strains with clinical significance are rare events. They have clinical, community, and livestock-associated significance. We aimed to screen these strains and evaluate the antibiogram through an array of antibiotics in Assam, a northeastern state of India. Method: S. aureus was confirmed biochemically and at the molecular level. Oxacillin and cefoxitin resistance were screened through the disc diffusion test. Hyperproduction of β-lactamase was screened using ticarcillin-clavulanic acid. PBP2a and PBP expressions were screened through mecA, mecC, and blaZ1, blaZ2 genes. MIC, MAR, MDR, XDR, and PDR were calculated. Findings: A total of 141 S. aureus isolates were screened. Altogether, 13 (9.22%) S. aureus isolates were mecA and/or mecC negative with oxacillin and/or cefoxitin resistance. Among the only oxacillin-resistant isolates, 33.33% (2/6) of the community-associated and 66.67% (2/3) of the livestock-associated isolates showed multiple drug resistance (MDR) with MAR index > 0.2. All the community-associated isolates showed resistance to oxacillin, while 83.33% showed resistance to ciprofloxacin & ticarcillin-clavulanic acid and 66.67% to fusidic acid. The livestock-associated isolates were 100% resistant to oxacillin, methicillin, and ticarcillin-clavulanic acid. All the oxacillin with cefoxitin-resistant isolates were MDR. Only one XDR was detected. One community-associated isolate was found to be BORSA, whereas the rest were MODSA. Altogether 61.54% had MAR index >0.2. Fusidic acid (0.064-0.125 µg/ml) had the lowest range of MIC, whereas trimethoprim, rifampicin, penicillin, and cefoxitin had higher ranges of MIC. Novelty: To the best of the authors’ knowledge, BORSA and MODSA from community and livestock-associated samples are not reported from this region. We assessed the antibiogram against 28 antibiotics (19 classes) and MIC against 12 antibiotics (11 classes). Reporting of MODSA strain from human community samples and livestock samples has great clinical importance from both human and veterinary perspectives. Keywords: MODSA, MDR, XDR, MAR, MIC, BORSA

Background: This study aimed to investigate the persistence of Foot-and-Mouth Disease Virus (FMDV) in clinically recovered cattle following an outbreak, focusing on both local indigenous breeds (Lakhimi) and crossbred cattle (Holstein Friesian-cross) in Assam. Methods: A total of 129 cattle (36 local and 93 crossbred), clinically recovered from FMD, were included in the study. Oropharyngeal fluid (OPF) samples (n=178) were collected at various intervals post-recovery. FMDV detection was carried out using three molecular diagnostic techniques: Multiplex PCR, reverse transcription loop-mediated isothermal amplification (RT-LAMP) and SYBR Green real-time PCR, all targeting the FMDV 3D gene. Result: FMDV was detected in 38 samples (21.35%) by multiplex PCR, 47 samples (26.40%) by RT-LAMP and 49 samples (27.53%) by SYBR Green real-time PCR. While all three methods showed comparable diagnostic accuracy, real-time PCR proved to be the most sensitive, rapid, reliable and cost-effective technique. FMDV persistence was observed in 24.81% (32/129) of cattle up to the 1st month post-recovery, 11.63% (15/129) up to the 3rd month and 1.55% (2/129) up to the 6th month. Local non-vaccinated Lakhimi cattle exhibited higher rates of viral persistence for serotype O, with 33.33% (12/36), 22.22% (8/36) and 5.55% (2/36) showing persistence at the 1st, 3rd and 6th months post-recovery, respectively. In contrast, vaccinated Holstein Friesian-cross cattle, demonstrated lower persistence rates, with 19.23% for Serotype A and 22.39% for Serotype O at the 1st month and 10.45% for Serotype O at the 3rd month post-recovery. Importantly, no transmission of the virus to healthy in-contact animals was detected during the study period. Statistical analysis (P=0.23, Chi-square=5.57) revealed no significant difference in viral persistence between local and crossbred cattle, suggesting that factors beyond vaccination status might influence FMDV persistence. However, the findings underscore the critical role of vaccination in reducing viral persistence in recovered cattle.

Background: Swinepox is an economically important, classical pox disease of piglets. The present study was undertaken with a view to develop rapid serological tests to diagnose the disease. Methods: During the study period, 25 suspected swinepox outbreaks in Assam were confirmed by polymerase chain reaction with sequencing and phylogenetic analysis, further the outbreaks were confirmed by transmission electron microscopy (TEM) for identification of swinepox positive samples. The positive samples were used to isolate the virus in PK-15 cell line and develop indirect and sandwich ELISA. Result: The cell culture-based indirect ELISA was developed that demonstrated an accuracy of 88.8% compare to VNT and 100% sensitivity with 66.67% specificity, could identify 61.71% seroprevalence of swinepox in random pig serum samples. A sandwich ELISA was also developed with polyclonal sera raised in rabbits as coating antibody and swinepox positive pig serum as tracing antibody. The sandwich ELISA detected 77.78% positive cases compared to PCR. Swinepox is an emerging disease in North-eastern region with high sero-positivity observed during random sampling. This is the first report of using immune sorbent assays to detect swinepox.

Mutations in XRCC1 can disrupt essential protein-protein interactions required for DNA base excision repair, potentially leading to genomic instability and increased cancer risk. This study employs large-scale molecular dynamics simulations to investigate the structural and functional consequences of the R399Q mutation on interactions with DNA ligase IIIα and DNA polymerase β. The results reveal that while the mutant protein retains a stable interaction with DNA ligase IIIα, key residues such as Gly 511, Glu 538, Arg 564, Thr 567 and Ala 568, which form critical hydrogen bonds, exhibit subtle rearrangements. In contrast, binding to DNA polymerase β is significantly destabilized, disrupting key interactions involving Glu 85, Ser 92, Arg 109 and Gly 556. Free energy calculations confirm a substantial reduction in binding affinity between the mutant protein and DNA polymerase β, suggesting an impaired repair efficiency. Unlike previous studies that relied on static structural models or biochemical characterizations, this research provides dynamic, atomic-level insights into how the mutation alters protein stability and interactions over biologically relevant timescales. These findings reconcile conflicting experimental observations and establish a computational framework for understanding mutation-driven defects in DNA repair. Interestingly, the data generated by these extensive simulations resemble empirical findings regarding XRCC1's interactions with BER enzymes. The study thus provides valuable insights into how the R399Q mutation impairs XRCC1's interactions with key DNA repair enzymes, potentially leading to defects in the DNA repair pathway and offering a computational perspective that aligns with experimental observations.

In vitro capacitation allows for a greater understanding of the mechanisms underlying fertilization and the development of improved reproductive techniques for improving fertility rates in porcine. Tyrodes albumin lactate pyruvate (TALP) and modified Krebs Ringers Broth (m-KRB) are two medias that are commonly used in research experiments to induce capacitation in boar spermatozoa (Ca & ntilde;& oacute;n-Beltr & aacute;n et al., Theriogenology, 198, 2023 and 231; Oberlender et al., Archivos de Medicina Veterinaria, 44, 2012 and 201; Sahoo et al., International Journal of Biological Macromolecules, 241, 2023 and 124502). Moreover, understanding the morphological and functional changes in boar spermatozoa at different hours of capacitation periods might aid in the development of novel techniques for improving sperm quality and increasing the litter size. This study was carried out to investigate the effect of Tyrode albumin lactate pyruvate and modified Krebs Ringers Broth media on in vitro capacitation of HD-K75 boar spermatozoa at three different periods of incubation. A total of 24 ejaculate from four clinically healthy, 10-12 months aged HD-K75 boars, maintained at ICAR-All India Coordinated Research Project (AICRP) on pig were selected. Semen was collected by 'Simple fist' method using a portable dummy. The semen samples having 200 mL volume, 10(3) x 10(6) spermatozoa/ml concentration and 70% initial motility were selected and split into two parts and suspended in TALP and m-KRB media, respectively, and incubated for 5 h at 37 degrees C. Seminal parameters viz. sperm viability, plasma membrane integrity and acrosomal integrity were estimated in the samples at 0, 3 and 5 h of incubation. This study revealed that there was significant variation between media in live acrosome-reacted (p < .05) and HOST-reacted (p < .01) spermatozoa, while between capacitation periods significant (p < .01) variation was observed in hyperactivated spermatozoa, live acrosome-reacted spermatozoa, HOST-reacted spermatozoa, FITC-labelled PSA, extracellular protein and sperm cholesterol. Non-significant variation was observed in total phospholipid. TALP showed overall better consequence on sperm viability, plasma membrane and acrosomal integrity of boar spermatozoa. From this study, it could be concluded that both TALP and m-KRB media were virtuous to induce capacitation in HD-K75 boar spermatozoa. TALP media, however, had a better effect on sperm viability, plasma membrane and acrosomal integrity of boar spermatozoa. Out of the three different periods, 3 h capacitation period resulted in significantly (p < .01) higher incidence of sperm viability, plasma membrane and acrosomal integrity in HD-K75 boar spermatozoa.

This study investigates the phytoconstituents of Myrica esculenta fruit extracts using various solvents, including n-hexane, dichloromethane, ethyl acetate, methanol, and water. Qualitative phytochemical analysis revealed the presence of several phytochemicals, with the highest concentration found in the methanol extract. The total phenolic (94.5±0.96 mg gallic acid equivalent (GAE)/g) and flavonoid (74.27±0.29 mg quercetin equivalent (QE)/g) contents were also highest in the methanol extract. Antioxidant activity was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic) acid (ABTS), and Ferric Reducing Antioxidant Power (FRAP) assays. The methanol extract exhibited superior antioxidant activity with DPPH and ABTS IC50 values of 22.27±0.98 μg/ml and 19.69±0.36 μg/ml, respectively, compared to ascorbic acid. FRAP activity was also highest in the methanol extract (87.125±0.33 mg Trolox equivalents (TE)/g). Gas Chromatography-Mass Spectrometry (GC-MS) analysis identified antioxidant compounds hexanedioic acid, bis(2-ethylhexyl) ester, methyl 11,12-octadecadienoate, and pentadecanoic acid. while Fourier Transform Infrared Spectroscopy (FTIR) analysis detected functional groups such as alkenes, ketones, esters, alcohols and carboxylic acids. These findings suggest that the methanolic extract of M. esculenta fruits is a rich source of natural antioxidants, making it suitable for pharmaceutical, health, and nutritional supplements aimed at enhancing overall health.

Background: Interaction between nutrition and reproduction has been established to play an important role in reproductive performance of animals. Zinc is considered to be an essential element required for reproduction. The present study was conducted to evaluate the efficiency of nano zinc (NZn) as feed supplementation on reproductive performance of Assam Hill goats. Methods: A total of twenty-four numbers of 7 days post kidding doe maintained at Goat Research Station, Assam Agricultural University, Burnihat were randomly selected and divided into 4 groups comprising 6 animals in each group. The control group animals were fed with basal diet without zinc supplementation however, all the animals of the treatment groups received 25 mg NZn, 35 mg NZn and 50 mg NZn/kg concentrate mixture with basal diet for a period of three months. Does were bred naturally at 24 hours from the onset of oestrus and confirmed for pregnancy after two months. Parturition behaviour was observed closely from two days before the expected date of kidding upto the period of placental expulsion. Result: Supplementation of 50 mg NZn to the basal diet of postpartum Assam Hill Goat significantly improved the reproductive performance by decreasing postpartum oestrus interval and increasing conception rate (83.33%).

This study investigates the epidemiology of subclinical mastitis, focusing on prevalence, risk factors, bacterial pathogens, virulence factors, antimicrobial sensitivity, and detection of methicillinresistant Staphylococcus aureus (MRSA) bacterial isolates in organized and unorganized dairy farms of Kamrup and adjoining districts of Assam. The overall prevalence of bovine subclinical mastitis was found to be 43.81% using the California Mastitis Test (CMT). Risk factor analysis revealed that age-wise, the highest prevalence was noted in the 4-6 years age group (51.95%) and at 4th lactation (60.40%). Significant associations were found between mastitis prevalence and various factors including age, breed, lactation number, stage of lactation, quarter-wise distribution, farm type, management system, and season. A total of 185 bacterial isolates were obtained, predominantly Staphylococcus spp. (143), with notable occurrences of Streptococcus spp. (22), Escherichia coli (14), and Enterococcus faecalis (6). Staphylococcus aureus emerged as the primary etiological agent, with 81.82% of isolates producing coagulase and 45.45% producing hemolysin, while 54.0% of Staphylococcus aureus isolates tested positive for the protein A (spa) gene. Antimicrobial sensitivity testing revealed enrofloxacin, gentamicin, and ceftriaxone as the most effective antibiotics, with penicillin-G demonstrating the least efficacy. Methicillin resistance was detected in 11.96% of Staphylococcus aureus isolates phenotypically and in 2.56% genotypically (mecA) revealing the emergence of MRSA which is important from a public health point of view. These findings highlight the prevalence of subclinical mastitis, the predominance of Staphylococcus aureus as the causative agent, and the emergence of antimicrobial resistance, which warrants effective control measures and antimicrobial management in dairy farming practices.

A bacterial disease, flacherie, which is more prevalent in silkworms causes heavy loss to the silk industry. This disease is typified by the flaccid condition of the affected larvae and caused by bacteria and non-occluded viruses individually and in combination. It is one of the major contributing factors to cocoon crop loss in India. The present work aims to isolate Lactic acid bacteria (LAB) residing in the gut of Eri silkworm and decipher its antagonistic activity against selected pathogens of silkworm which are responsible for causing flacherie in silkworm. Lactic acid bacteria Ligilactobacillus salivarius was isolated from the midgut of Eri silkworm and it exhibited antibacterial activity against Staphylococcus aureus, Proteus vulgaris and Bacillus thuringiensis. Other than preventive measures, no remedial measure, so far, have been developed to check the infection and further spread of the disease. In this context, the present study reveals the role of LAB residing in the gut of Eri silkworm and its essential role in formulating probiotic for Eri culture.

Background: Eri silkworm rearing, crucial to Assam’s economy, faces severe productivity threats from disease and crop loss. These challenges impact farmers’ livelihoods, highlighting the urgent need for innovative solutions to boost disease resistance and crop yield, ensuring the industry’s sustainability and profitability. Methods: The study investigated the detection of Lactobacillus species in the midgut of the Eri silkworm (Samia ricini, Donovan) collected from Borduar, Assam. The research involved identifying Ligilactobacillus salivarius in the midgut of 5th instar larvae of the Borduar ecorace of Eri silkworm. The larvae, reared separately on castor and kesseru host plants, were utilized for isolating Lactobacillus on MRS agar. Molecular identification of these isolates was achieved through 16S rRNA sequence analysis. Result: Ligilactobacillus salivarius, a species under the genus Lactobacillus, was identified for the first time in the midgut of Eri silkworm larvae. This bacterium is widely known as a potential probiotic in higher animals, particularly poultry, indicating its possible benefits for silkworm health. The discovery of Ligilactobacillus salivarius in silkworms paves the way for further research aimed at developing novel probiotics tailored specifically for the sericulture industry, potentially improving silkworm health and boosting productivity. Implementing these probiotics presents a promising solution to the challenges facing sericulture in Assam, offering enhanced disease resistance and crop yield.

Background: The present study was carried out to evaluate in-vitro toxicity associated with chitosan nanoparticles, Gantrez® nanoparticles and poly-lactide co-glycolide (PLG) microparticle in Vero cell line. The cytotoxicity of all three micro/nano-particles was assessed using different concentration. Methods: For each concentration of these delivery systems, the confluent monolayer of Vero cells was treated for a period of 48 hours and studied for morphological alteration and cell survivability after the treatment. Results: It was observed that the different concentrations of chitosan nanoparticles and Gantrez® nanoparticles did not have significant effect on the cell viability as evident from the non-significant difference between the OD540 of formazan product formed from MTT in treated and untreated cells. The concentration of chitosan nanoparticles and Gantrez® nanoparticles up to 1000 µg/ml did not have any influence in cellular metabolic activities and viability. However, a slight reduction (statistically insignificant) in the cellular viability and metabolic activities were observed when PLG microparticles were used at 1000 µg/ml.

Prostate cancer is the World's second most common cancer, with the fifth-highest male mortality rate. Point mutations such as T877A and W741L are frequently seen in advanced prostate cancer patients, conferring drug-resistance and hence driving cancer growth. Such occurrence of drug resistance in prostate cancer necessitates designing of suitable ligands to ensure better interactions with the receptors which can block the progression of the disease. The present study focus on the modification of plant-derived flavonoids that might act as inhibitors against such point mutations namely, T877A and W741L. In T877A mutation threonine is substituted by alanine at the 877 codon and W741L mutation, tryptophan is substituted by lysine at the 741 codon in prostate cancer. The study revolved on the aspect of the evaluation of Isobavachin and its derivatives as a potential agent to tackle such point mutations by using the in silico approach. A total of 98 molecular dockings were performed to find the ligand-receptor complexes with the lowest binding energy employing Autodock Software to conduct the blind and site-specific docking. Additionally, ligands were screened for Drug-likeness and toxicity using several tools yielding eight possible drug candidates. Based on the results of Molecular Docking, Drug-likeness, and ADMET testing, ten structures, including six complexes and three receptors were subjected to molecular dynamics simulation of 100 ns covering RMSD, RMSF, Rg, and MM/PBSA. Based on the simulation results, Isobavachin, IsoMod4, and IsoMod7 were concluded to be stable and exhibited potential properties for developing a novel drug to combat prostate cancer and its associated drug-resistance.Communicated by Ramaswamy H. Sarma.

Checkpoint kinases Chk1, Chk2, Wee1 are playing a key role in DNA damage response and genomic integrity. Cancer-associated mutations identified in human Chk1, Chk2, and Wee1 were retrieved to understand the function associated with the mutation and also alterations in the folding pattern. Therefore, an attempt has been made to identify deleterious effect of variants using in silico and structure-based approach. Variants of uncertain significance for Chk1, Chk2, and Wee1 were retrieved from different databases and four prediction servers were employed to predict pathogenicity of mutations. Further, Interpro, I-Mutant 3.0, Consurf, TM-align, and have (y)our protein explained were used for comprehensive study of the deleterious effects of variants. The sequences of Chk1, Chk2, and Wee1 were analyzed using Clustal Omega, and the three-dimensional structures of the proteins were aligned using TM-align. The molecular dynamics simulations were performed to explore the differences in folding pattern between Chk1, Chk2, Wee1 wild-type, and mutant protein and also to evaluate the structural integrity. Thirty-six variants in Chk1, 250 Variants in Chk2, and 29 in Wee1 were categorized as pathogenic using in silico prediction tools. Furthermore, 25 mutations in Chk1, 189 in Chk2, and 14 in Wee1 were highly conserved, possessing deleterious effect and also influencing the protein structure and function. These identified mutations may provide underlying genetic intricacies to serve as potential targets for therapeutic inventions and clinical management.

Prostate cancer is the World's second most frequent malignancy, with the fifth-highest male mortality rate. In advanced prostate cancer patients, point mutations such as T877A and W741L are prevalent, imparting treatment resistance and hence promoting cancer development. The emergence of drug resistance in prostate cancer necessitates the development of suitable ligands to allow for stronger interactions with the receptors, which can inhibit cancer progression. The present study focuses on flavonoids produced by plants, which may act as inhibitors of point mutations like T877A and W741L in prostate cancer. This research was conducted using an in-silico method where the compound Glabranin and its derivatives were virtually screened to identify potential drugs for combating such point mutations. Thirty-five Molecular Dockings were performed to find the ligand-receptor complexes with the lowest binding energy. Moreover, employing a variety of tools, ligands were evaluated for drug-likeness and toxicity, indicating a promising drug candidate. Based on the results of Molecular Docking, Drug-likeness, and ADMET testing, eight structures were subjected to a 100 ns Molecular Dynamics simulation. A QSAR analysis was also performed based on the simulation findings. In this study, it was revealed that GlaMod2 phytocompound was effective against T877A and W741L mutations in prostate cancer. It was observed that the phytocompound was stable and had potential properties for the development of a novel drug to combat prostate cancer and drug resistance This phytocompound may therefore be effective in the development of prostate cancer inhibitors for patients with mutant androgen receptors.

BACKGROUND: Semen cryopreservation is a complex process during which there is alteration in the expression of sperm and seminal plasma proteins, molecular weight of protein or loss of membrane proteins during the process. In order to compensate for these changes, different membrane stabilizers are used in freezing semen extenders. However, there is scarcity of such studies during cryopreservation of goat semen. OBJECTIVE: To investigate the effect of membrane stabilizers on sperm membrane protein expression during cryopreservation of goat semen. MATERIALS AND METHODS: A total of 36 semen ejaculates from nine Assam Hill Goat bucks aged 2 to 2.5 years was collected by artificial vagina method. Three membrane stabilizers, each at two different concentrations viz. 50 and 80 mM sucrose, 50 and 100 mM trehalose, and 100 and 150 ng/mL IGF-1 (insulin-like growth factor 1 protein) were added to Tris-citric acid fructose egg yolk glycerol (TCFEYG) extender and semen samples were cryopreserved. The sperm membrane protein profile was studied in fresh and cryopreserved semen by SDS-PAGE. RESULTS: SDS- PAGE of sperm membrane extract of fresh semen revealed the presence of 24 protein bands with molecular weights ranging from 10 kDa to 240 kDa. Samples supplemented with 50 mM sucrose and 80 mM sucrose revealed 21 protein bands with molecular weights ranging from 10 kDa to 240 kDa. All the 21 protein bands were same as those observed in the sperm membrane of fresh spermatozoa, except that the 23 kDa, 29 kDa and 42 kDa bands were absent in frozen semen. Similarly, frozen semen extended with 50 mM trehalose and 100 mM trehalose revealed 22 protein bands with molecular weights ranging from 10 kDa to 240 kDa, but lacking the 29 kDa and 42 kDa bands. Proteins with molecular weights of 29 kDa, 130 kDa and 240 kDa were absent in frozen semen supplemented with 100 ng/mL IGF-1 and 150 ng/mL IGF-1. CONCLUSION: The present study revealed that supplementation of tris basic extender with trehalose at 100 mM and or IGF-1 at 100 ng/mL or 150 ng/mL improves the post-thaw semen characteristics and protects certain fertility related sperm membrane proteins.