Scrotal circumference: A predictor of testosterone concentration and certain attributes of seminal vesicles influencing buffalo male fertility

AIM: The aim of this study was to evaluate the relationship of scrotal circumference (SC) with plasma testosterone, seminal vesicles (SVs) weight, and its secretion as measurable indicators of fertility and also to sequence and establish phylogenetic relatedness of certain SV protein genes with other species as such integrated approach is lacking. MATERIALS AND METHODS: Altogether, 59 apparently healthy male buffaloes sacrificed at slaughterhouse were selected (irrespective of breed) for measuring SC and collecting blood and paired SVs. The SC was measured at greater curvature using soft thread. In the present study, blood plasma testosterone, cholesterol, protein, and glucose in addition to SV fructose, citric acid and proteins in SV fluid were also estimated. The SV tissue was fixed in RNAlater for RNA extraction. Male buffaloes were categorized as per total SV weight into Group I (<5.0 g), Group II (5.0-7.84 g), and Group III (>8.0 g) and dentitions-I (≤18 months), II (18-24 months), and III (≥24 months) to assess the effect of weight and dentition age on SC, SV weight, and its certain secretions. Data were analyzed using linear model procedure including Tukey HSD test and Pearson’s correlation coefficient. Variance inflation and condition index were also used to assess multicollinearity. RESULTS: Gross and histomorphological evaluation of SVs did not show any abnormality. Macronutrients (plasma protein, glucose, and cholesterol) showed non-significant (p>0.05) variation between groups. The SC and SV weight varied significantly (p<0.05) with a significant positive relationship with plasma testosterone, SV protein, fructose, and citric acid. In addition, testosterone concentration also showed increasing trend from Groups I to III but increased significantly (p<0.05) from Group II to III with positive and significant correlations with SV protein, fructose, and citric acid similar to SV weight and SC. Binders of sperm protein (BSP1, 3, and 5) genes (full length) were sequenced and established an evolutionary relationship which is lacking in buffalo. CONCLUSION: The present findings established a significant positive correlation of SC with that of other fertility parameters related to SVs weight and its secretions: Fructose, citric acid, and protein (inclusive of BSPs sequenced full length), and testosterone. Therefore, the present integrated approach along with certain semen quality attributes reflecting epididymis function could be used as a predictive fertility marker for grading and selection of breeding bulls and their progenies to develop outstanding bull mother farm.