Flaxseed oil modulates semen production and its quality profiles, freezability, testicular biometrics and endocrinological profiles in mithun.

Mithun (Bos frontalis) is a unique domestic free range bovine species of North Eastern Hilly (NEH) regions of India. Effect of feed supplementation of Flaxseed oil (FSO) on semen production and its quality profiles, freezability, oxidative stress, apoptotic sperm percentage and subsequently on endocrinological profiles & scrotal and testicular biometrics in different seasons was studied in mithun. The experimental animals were divided into two groups, Gr I: Control (n = 3) and Gr II: Treatment (n = 3; Flaxseed oil @ 150 mL/day). FSO was supplemented through oral drench in the morning hours just before concentrate feeding. A total of 80 semen samples (n = 80; 20 semen samples from each season; each 10 semen samples from control and treatment groups per season) were collected, not more than twice per week in winter, spring, autumn and summer seasons. Semen quality profiles (SQPs) such as volume, sperm concentration, motility (forward progressive and total), motility & velocity profiles by computer assisted sperm analyser (CASA), viability, total sperm abnormality, acrosome integrity, plasma membrane & nuclear abnormality and apoptotic sperm percentage were estimated in fresh semen. Along with SQPs measured in fresh semen, motility in estrus bovine cervical mucus (bovine cervical mucus penetration test; BCMPT) and mitochondrial membrane potential (MMP) by JC-1 stain were determined in the post-thawed semen samples. Biochemical profiles (aspartate aminotransferase; AST, alanine aminotransferase; ALT, total cholesterol; CHO), antioxidant profiles (superoxide dismutase; SOD, catalase; CAT, glutathione; GSH, total antioxidant capacity; TAC) and oxidative stress profile (malondialdehyde; MDA) were estimated in fresh semen whereas AST, ALT, lactate dehydrogenase (LDH), TAC and MDA were estimated in the frozen thawed semen samples. Endocrinological profiles such as follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, cortisol and thyroxin and scrotal circumference (SC) & testicular biometrics were measured in both groups in different seasons. Result revealed a significant (p < 0.05) improvement in motility (total & forward progressive, motility & velocity by CASA and vanguard distance in cervical mucus), viability, intactness of acrosome & plasma membrane, MMP, antioxidant profiles and reduction in total sperm and nuclear abnormalities, reduction in leakage of intracellular enzymes and reduction in oxidative stress profile and reduction of apoptotic sperm percentage were observed in FSO supplemented than in un-supplemented control group accordingly in fresh and post thawed semen samples. Blood FSH, LH, testosterone and thyroxin concentration were significantly (p < 0.05) increased and cortisol concentration was significantly (p < 0.05) decreased in FSO supplemented group than in unsupplemented control group. Similarly, SC and testicular biometrics were increased significantly (p < 0.05) in supplemented than unsupplemented group for different seasons and significantly (p < 0.05) higher in winter and spring than in summer season in the experimental groups. It can be concluded from the study that supplementation of FSO can effectively be utilized to improve the antioxidant profiles, reduction of oxidative stress with cascading beneficial effects on SQPs and fertility status of the mithun bull.

Effect of season and age on scrotal circumference, testicular parameters and endocrinological profiles in mithun bulls.

Mithun is a domesticated free-range bovine species primarily used as a meat animal and is a pride of North Eastern Hilly regions of India. The present study was conducted to measure the effect of seasons on scrotal & testicular biometrics and endocrinological profiles for different age groups at different seasons in mithun bulls. A total of 30 mithun males were selected from the mithun breeding farm, ICAR-NRC on Mithun, Medziphema, Nagaland, India and were equally distributed into five groups based on their age. Each group consisted of six animals and the groups were Gr A (0.1-1.0 year), Gr B (1.1-2.0 years), Gr C (2.1-3.0 years), Gr D (3.1-5.0 years) and Gr E (5.1-6.0 years). The seasons were grouped into winter, spring, summer and autumn based on the meteorological data such as temperature humidity index (THI) and sunshine hours. Scrotal circumference (SC) & testicular biometrics and endocrinological profiles such as follicle stimulating hormone (FSH), luteinizing hormone/interstitial cell stimulating hormone (LH/ICSH), testosterone, thyroxine (T4), cortisol and insulin like growth factor 1 (IGF 1) were estimated during different seasons for different age groups. Statistical results revealed that the SC & testicular biometrics and endocrinological profiles differed significantly (p < 0.05) among the different age groups for the same season whereas SC and endocrinological profiles significantly (p < 0.05) differed among the seasons for same age group. Significantly (p < 0.05) greater SC and testicular weight were observed in Gr E and D, lower in Gr A and B and intermediate in Gr C and increased as age advances. Significantly (p < 0.05) greater SC was observed in winter and spring and lowest was in summer season. The hormone profiles such as FSH, LH/ICSH, testosterone & thyroxine were significantly (p < 0.05) greater and IGF-1 & cortisol were significantly (p < 0.05) lower in spring & winter than in summer season. The hormones, FSH, LH/ICSH and thyroxine increased significantly in Gr A followed by reduced in Gr B and then increased to Gr D and E, whereas concentration of testosterone, cortisol and IGF-1 increased according to age advanced. It was concluded that the spring and winter seasons has significantly greater beneficial effects than summer season on reproduction and artificial breeding programme in semi-intensive management of mithun in the present location.