The present study was undertaken to assess the effect of melatonin (MT) on sperm motility, viability, total sperm abnormality, acrosomal and plasma membrane integrity, DNA abnormality, antioxidant profiles such as superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and total antioxidant capacity (TAC), enzymatic profiles such as aspartate amino transaminase (AST), alanine amino transaminase (ALT), and biochemical profiles such as malonaldehyde (MDA) production and cholesterol efflux. Total numbers of 30 ejaculates were collected twice a week from eight mithun bulls and semen was split into five equal aliquots, diluted with the TEYC extender. Group 1 has semen without additives (control) and group 2 to group 5 have semen that was diluted with 1 mM, 2 mM, 3 mM, and 4 mM of melatonin, respectively. These seminal parameters, antioxidant, enzymatic, and biochemical profiles were assessed at 5°C for 0, 6, 12, 24, and 30 h of incubation. Inclusion of melatonin into diluent resulted in significant (P<0.05) decrease in percentages of dead spermatozoa, abnormal spermatozoa, and acrosomal abnormalities at different hours of storage periods as compared with control group. Additionally, melatonin at 3 mM has significant improvement in quality of mithun semen than melatonin at 1 mM, 2 mM or 4 mM stored inin vitrofor up to 30 h. It was concluded that the possible protective effects of melatonin on sperm parameters are it prevents MDA production and preserve the antioxidants and intracellular enzymes during preservation.

The present study was undertaken to assess the effect of taurine on sperm motility, viability, total sperm abnormalities, acrosomal and plasma membrane integrity, enzymatic profiles such as reduced glutathione (GSH), glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase (CAT), and biochemical profiles such as cholesterol efflux and malondialdehyde (MDA) production. A total of 50 ejaculates were collected twice a week from 8 mithun bulls, and semen was split into 4 equal aliquots and diluted with the TEYC extender. Group 1: semen was without additives (control); groups 2 to 4: semen was diluted with 25 mM, 50 mM, and 100 mM of taurine, respectively. Seminal parameters and enzymatic and biochemical profiles were assessed at 5°C. Inclusion of taurine into diluent resulted in significant (P < 0.05) decreases in percentages of dead spermatozoa, abnormal spermatozoa, and acrosomal abnormalities after liquid storage compared with the control group. Additionally, taurine at 50 mM has significant improvement in quality of mithun semen than taurine at 25 or 100 mM stored in in vitro at 5°C. It was concluded that the possible protective effects of taurine on sperm parameters are from enhancing the function of antioxidant enzymes, preventing efflux of cholesterol from cell membranes and decreased MDA production.

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The current study aimed at genomic characterization and improved understanding of genetic diversity of two Indian mithun populations (both farm, 48 animals and field, 24 animals) using genome wide genotype data generated with Illumina BovineHD BeadChip. Eight additional populations of taurine cattle (Holstein and NDama), indicine cattle (Gir) and other evolutionarily closely related species (Bali cattle, Yak, Bison, Gaur and wild buffalo) were also included in this analysis (N = 137) for comparative purposes. Our results show that the genetic background of mithun populations was uniform with few possible signs of indicine admixture. In general, observed and expected heterozygosities were quite similar in these two populations. We also observed increased frequencies of small-sized runs of homozygosity (ROH) in the farm population compared to field mithuns. On the other hand, longer ROH were more frequent in field mithuns, which suggests recent founder effects and subsequent genetic drift due to close breeding in farmer herds. This represents the first study providing genetic evidence about the population structure and genomic diversity of Indian mithun. The information generated will be utilized for devising suitable breeding and conservation programme for mithun, an endangered bovine species in India.

Background Mithun ( Bos frontalis ), also called gayal, is an endangered bovine species, under the tribe bovini with 2n = 58 XX chromosome complements and reared under the tropical rain forests region of India, China, Myanmar, Bhutan and Bangladesh. However, the origin of this species is still disputed and information on its genomic architecture is scanty so far. We trust that availability of its whole genome sequence data and assembly will greatly solve this problem and help to generate many information including phylogenetic status of mithun. Recently, the first genome assembly of gayal, mithun of Chinese origin, was published. However, an improved reference genome assembly would still benefit in understanding genetic variation in mithun populations reared under diverse geographical locations and for building a superior consensus assembly. We, therefore, performed deep sequencing of the genome of an adult female mithun from India, assembled and annotated its genome and performed extensive bioinformatic analyses to produce a superior de novo genome assembly of mithun. Results We generated ≈300 Gigabyte (Gb) raw reads from whole-genome deep sequencing platforms and assembled the sequence data using a hybrid assembly strategy to create a high quality de novo assembly of mithun with 96% recovered as per BUSCO analysis. The final genome assembly has a total length of 3.0 Gb, contains 5,015 scaffolds with an N50 value of 1 Mb. Repeat sequences constitute around 43.66% of the assembly. The genomic alignments between mithun to cattle showed that their genomes, as expected, are highly conserved. Gene annotation identified 28,044 protein-coding genes presented in mithun genome. The gene orthologous groups of mithun showed a high degree of similarity in comparison with other species, while fewer mithun specific coding sequences were found compared to those in cattle. Conclusion Here we presented the first de novo draft genome assembly of Indian mithun having better coverage, less fragmented, better annotated, and constitutes a reasonably complete assembly compared to the previously published gayal genome. This comprehensive assembly unravelled the genomic architecture of mithun to a great extent and will provide a reference genome assembly to research community to elucidate the evolutionary history of mithun across its distinct geographical locations. Electronic supplementary material The online version of this article (10.1186/s12864-019-5980-y) contains supplementary material, which is available to authorized users.