7.
Season-Based Anatomical, Histological And Functional Modulations In Testes Of Nili-Ravi Buffalo Bulls In Sahiwal And Bahawalpur Divisions
by Sajid Hameed (2012-VA-651) | Dr. Saima Masood | Dr. Muhammad Younis | Dr. Hafsa Zaneb | Prof. Dr. Muhammad Sarwar Khan.
Material type: ; Literary form:
not fiction
Publisher: 2015Dissertation note: Morphometric/histomorphometric analysis on testes of any species is necessary to assess qualitative changes in testicular components and spermatogenic functions. Testicular biometry, histomorphometry of seminiferous tubules, semen characteristics and dimensional characteristics of spermatozoa are generally affected by the climatic variations. In Pakistan, breeding bulls are kept at different semen productions units located in different climatic zones without any consideration of the climatic conditions and scientific justifications. In this breed until now, few reports are available on the seasonal variations in testicular biometry and semen characteristics. Seasonal influence on histomorphometry and dimensional characteristics of spermatozoa has not been studied before in this breed. Furthermore, all these parameters have not yet been studied in different climatic zones simultaneously to investigate the comparative climatic effect on the bull performance which may form the basis for keeping Nili-Ravi buffalo breeding bulls under best climatic zone for optimal performance.
Keeping in view the above facts and gaps, the present study was conducted with objectives; to study the climate-led modulations in biometry and histomorphometry of testes, semen characteristics and dimensional characteristics of spermatozoa in Sahiwal and Bahawalpur divisions (two different climatic zones of Punjab) and to study the modulations in biometry and histomorphometry of testes, semen characteristics and dimensional characteristics of spermatozoa due to seasonal variations within each climatic zone in Nili-Ravi buffalo bulls. The study was carried out in Sahiwal and Bahawalpur divisions simultaneously for the period of one year divided into seasons (autumn, spring, dry summer, humid summer and winter). The study was accomplished in a set of two experiments. In Experiment-I, testicular biometry and
Summary
140
histomorphometry was studied in Nili-Ravi buffalo bulls in both the divisions. For testicular biometry, 14 adult Nili-Ravi buffalo breeding bulls (n=7 from SPU Karaniwala, Bahawalpur; n=7 from SPU Qadirabad, Sahiwal), aged 5-8 years, were used. Body Weight and orchidometric parameters viz. Scrotal Circumference, Testicular Length, Testicular Width and Paired Testicular Volume were recorded fortnightly. Whereas, for histomorphometry of testes, 200 healthy adult Nili-Ravi buffalo bulls (n=20 during each season from each division), aged 5-8 years, slaughtered at abattoirs, were used. For this purpose, cube pieces of testicular parenchyma (about 1cm3) were collected, processed for paraffin sectioning techniques, and stained with haematoxylin and eosin. Diameter of Seminiferous Tubules and Seminiferous Epithelial Height were measured using software (PixelPro). In Experiment-II, semen characteristics and dimensional characteristics of spermatozoa were studied. For this purpose, semen was collected fortnightly from Nili-Ravi buffalo breeding bulls used in experiment-I, viz. {14 adult Nili-Ravi buffalo breeding bulls (n=7 from SPU Karaniwala, Bahawalpur; n=7 from SPU Qadirabad, Sahiwal), aged 5-8 years}. Semen characteristics; Semen Volume, Color, pH, Mass Motility, Percentage of Individual Motile Spermatozoa and Concentration of Spermatozoa were studied. Dimensional characteristics of spermatozoa from semen samples of all breeding bulls were studied using Eosin-Nigrosin stain. The six dimensional characteristics of spermatozoa viz. Head Length, Head Breadth, Head Shape, Mid-Piece Length, Tail Length and Total Sperm Length were studied on software (PixelPro).
Body weight, scrotal circumference, average testicular length, average testicular width and paired testicular volume were 706.05±3.03kg, 34.62±0.22cm, 13.45±0.07cm, 6.29±0.03cm and 640.65±11.51cm3respectively in Sahiwal division and 690.99±3.96kg, 32.93±0.19cm, 13.04±0.07cm, 6.08±0.03cm, 561.95±9.43cm3 respectively in Bahawalpur division. In Sahiwal
Summary
141
division, body weight was significantly higher (P<0.05) in autumn and winter, whereas in Bahawalpur division non-significant differences in body weight were observed among all the seasons with highest body weight in winter and lowest in humid summer. Overall mean body weight was significantly higher (P<0.05) in Sahiwal division as compared to Bahawalpur division. In Sahiwal division, highest scrotal circumference was found in autumn followed by spring, winter, humid summer and dry summer with non-significant differences among the seasons. Similar results were obtained in Bahawalpur division. It was recorded to be higher (P<0.05) in Sahiwal than Bahawalpur division. Pattern of seasonal variations in average testicular length was similar to that of scrotal circumference in both the divisions. Overall average testicular length was significantly higher (P<0.05) in Sahiwal division as compared to Bahawalpur division. Average testicular width was highest (P>0.05) in autumn in both divisions. Overall average testicular width was significantly higher (P<0.05) in Sahiwal division compared with Bahawalpur division. In both divisions, paired testicular volume was non-significantly higher (P>0.05) in autumn followed by spring, winter, humid summer and dry summer. Overall paired testicular volume was significantly higher (P<0.05) in Sahiwal division than Bahawalpur division. There was found a significantly positive (P<0.01) correlation between body weight and various testicular biometrical parameters in both the divisions. All the testicular biometrical parameters were also significantly positively (P<0.01) correlated with each other in both the divisions. Values of seminiferous tubule diameter and seminiferous epithelial height were 248.52±1.07μmand 70.03±0.46μm, respectively in Sahiwal division and 225.85±1.01μm and 66.03±0.42μm, respectively in Bahawalpur division. In both divisions diameter of seminiferous tubules was significantly higher (P<0.05) in autumn and spring. Lowest values were observed in dry summer in Sahiwal division, while it was lowest in humid summer in Bahawalpur division.
Summary
142
Seminiferous tubule diameter was significantly higher (P<0.05) in Sahiwal division than Bahawalpur division in all the seasons. Seasonal and climatic influence on the seminiferous epithelial height was almost similar to the seminiferous tubule diameter in both the divisions. Seminiferous tubule diameter showed a significantly positive (P<0.01) correlation with seminiferous epithelial height in both the divisions.
Ejaculatory volume, semen color score, pH, mass motility score, individual sperm motility and sperm concentration were4.63±0.11mL, 1.06±0.06, 6.48±0.04, 2.06±0.06, 66.02±0.76% and 1023.27±30.90 million/mL respectively in Sahiwal and 2.60±0.09mL, 0.88±0.08, 6.67±0.04, 1.86±0.09, 49.72±2.70% and 854.27±28.53 million/mL respectively in Bahawalpur division. In both the divisions non-significant difference (P>0.05) in ejaculatory volume was recorded in all the seasons with maximum volume in spring in Sahiwal division but in humid summer in Bahawalpur division. Ejaculatory volume was significantly higher (P<0.05) in Sahiwal division compared with Bahawalpur division in all the seasons. In Sahiwal division significantly higher (P<0.05) semen color score was observed in autumn, whereas it was non-significantly higher in autumn in Bahawalpur division. Overall, it was found non-significantly higher (P>0.05) in Sahiwal division as compared to Bahawalpur division during all the seasons. In Sahiwal division the significantly lowest (P<0.05) pH was observed in autumn. Significantly highest (P<0.05) pH was observed in winter. In Bahawalpur division pH was also lowest in autumn and highest in winter but the differences were non-significant. Overall pH was significantly lower (P<0.05) in Sahiwal division than Bahawalpur division. In Sahiwal division mass motility score was significantly higher (P<0.05) in autumn with lowest score in winter. In Bahawalpur division the non-significant effect of the season on mass motility was observed. It was non-significantly higher in Sahiwal division than Bahawalpur division. In Sahiwal division
Summary
143
significantly lowest (P<0.05) individual sperm motility was observed in winter and it was highest (P<0.05) in spring. In Bahawalpur division non-significant differences were observed among the seasons with maximum individual sperm motility in dry summer and minimum winter. It was significantly higher (P<0.05) in Sahiwal division than Bahawalpur division. In Sahiwal division significantly higher (P<0.05) sperm concentration was found in autumn with lowest value in winter. In Bahawalpur division there was non-significant influence of season. Overall sperm concentration was significantly higher (P<0.05) in Sahiwal division. In both divisions ejaculatory volume showed non-significant correlation with all other semen parameters. Semen pH showed significantly negative correlation (P<0.01) with mass motility, individual sperm motility and sperm concentration. Mass motility, individual sperm motility and sperm concentration showed significant positive correlation (P<0.01) with each other.
Sperm head length, head breadth, head shape, mid-piece length, tail length and total sperm length were 7.60±0.01μm, 4.80±0.02μm, 1.59±0.01, 11.54±0.02μm, 43.62±0.42μm and 62.75±0.42μm respectively in Sahiwal division and 7.58±0.01μm, 4.74±0.02μm, 1.60±0.01, 11.64±0.02μm, 39.88±0.51μm and 59.10±0.50μm respectively in Bahawalpur division. Season had non-significant effect (P>0.05) on the sperm head length in both the divisions. It was also non-significantly longer (P>0.05) in Sahiwal division as compared to Bahawalpur division. In both divisions significantly higher (P<0.05) value of sperm head breadth was found in autumn. Sperm head breadth was non-significantly higher (P>0.05) in Sahiwal division compared with Bahawalpur division in all the seasons. Sperm head shape value was significantly lower (P<0.05)in autumn than other seasons in Sahiwal division and almost similar results were obtained in Bahawalpur division. Overall it was non-significantly lower in Sahiwal division than Bahawalpur division. In both divisions the mid-piece length was significantly higher (P<0.05) in
Summary
144
winter than spring and lowest in the spring. Overall mid-piece was significantly shorter (P<0.05) in Sahiwal division. In Sahiwal division sperm tail was significantly longest (P<0.05) in autumn. In Bahawalpur division it was significantly longer (P<0.05) in autumn and spring. Overall the sperm tail was significantly longer (P<0.05) in Sahiwal division. The pattern of seasonal and climatic influence on total sperm length was almost similar to that of sperm tail length. Similar correlation results were observed in both the divisions. Head shape and mid-piece length had significant negative correlation (P<0.01) with other parameters. Head length, head breadth, tail length and total sperm length had significant positive correlation (P<0.01) with each other.
In overall, body weight and testicular biometrical parameters were negatively correlated with ejaculatory volume and pH, while positively correlated with semen color, mass motility, individual sperm motility and sperm concentration. In overall, body weight and testicular biometrical parameters had negative correlation with sperm head shape and mid-piece length (with some exceptions in Sahiwal division) and the positive correlation with head length, head breadth, tail length and total sperm length in both the divisions, non-significantly in Sahiwal, whereas significantly(P<0.01) in Bahawalpur division. In overall, semen color, mass motility, individual sperm motility and sperm concentration had negative correlation with sperm head shape and mid-piece length, whereas correlation was positive with sperm head length, head breadth, tail length and total sperm length. In contrary, pH had positive correlation with sperm head shape and mid-piece length, whereas correlation was negative with other sperm parameters in both the divisions. In conclusion, the milder seasons are favorable for optimal performance of Nili-Ravi buffalo bulls and climate of Sahiwal division is more favorable than that of Bahawalpur division.
Summary
145
In conclusion, testicular biometric / histomorphometric parameter values are better in autumn and spring than summer and winter seasons and in Sahiwal than Bahawalpur division. Likewise, superior quality semen is produced in autumn and spring than summer and winter seasons and in Sahiwal than Bahawalpur division. Autumn and spring seasons and climate of Sahiwal division have additive effect on sperm dimensions, except mid-piece length. Orchidometric parameters are positively correlated with semen quality. Diameter of seminiferous tubules is positively correlated with seminiferous epithelial height. Superior quality semen has a positive correlation with sperm head length, head breadth, tail length and total sperm length.
From the results of present study, it has been concluded that testicular biometry, histomorphometry, semen characteristics and dimensional characteristics of spermatozoa are influenced by the seasonal and climatic variation i.e. overall bull performance is influence by these variations. Nili-Ravi buffalo bulls perform better in autumn and spring than other seasons and in Sahiwal division than Bahawalpur division. Therefore, it is clear that the seasonal and climatic conditions of the region / location should be considered for the establishment of new semen production units for the optimal performance of the Nili-Ravi buffalo breeding bulls. Future studies are recommended on comparative fertility rates using the semen collected and cryopreserved from the bulls kept in different climatic zones. Availability: Items available for loan: UVAS Library [Call number: 2480-T] (1).
