الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
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Abstract
The aim of the present work was to threw some lights on the event of changes occurring in serum testosterone profile in male buffaloes under variable conditions as following :
1-The relation between serum testosterone levels and age,scrotal circumference and testicular size of male buffaloes.
2-The relation between testosterone levels and seminal gland biometry and fructose contents.
3-Seasonal variations in serum testosterone levels in aged buffalo bulls.
Therefore, a total number of 120 blood serum samples were taken from male buffaloes for testosterone determination. The studied animals were classified into 3 main groups, according to the requested different aims of the present thesis.
group ( І ) Slaughterhouse materials: Thirty (30) blood samples from apparently healthy slaughtered male buffaloes of unknown breeding histories were taken and divided into three age groups, 1.5 – 1.8 years, 2 – 2.5 years and 3 – 4 years. Blood samples were centrifuged at 5000 rpm for 10 minutes and serum was aspired by clean sterile micropipette and stored frozen at -20 c ͦ till hormonal assay.
Scrotal circumference was conducted by using a flexible measuring tape around the greatest diameter of the scrotum.
Testicular measurements, length (fom upper pole to lower pole), width (medio-lateral), as well as depth (cranio- caudal) were measured by caliper. Testicular volume was calculated using the following formula: Volume (c.cm) = length (L)×width (W)×Depth (D)×0.52.
Seminal glands were obtained immediately after slaughter. Each seminal gland (right and left) was dissected carefully from its surrounding peritoneum, then each gland weighed in grams. Seminal gland biometry measured using centimeter ruler and caliper. After that tissues of the seminal glands were kept at −20°C until fructose determination.
Fructose was determined in tissue of seminal gland after extraction using spectrophotometer at 540 nm , and the results were calculated from a calibration curve prepared with standard solutions of pure fructose.
group (П) Farm animal materials: Fifty one (51) blood samples were collected from two local farms. The age of studied male buffaloes ranged from 4 to 84 months. These animals were healthy and free from any infectious diseases. Animals were kept almost under the same managemental conditions of each farm. Scrotal circumference and Testicular measurements were taken as mentioned.
group (Ш) Seasonal effect : In order to investigate the effect of seasons on serum testosterone levels, 4 adult buffalo bulls raised in Veterinary Medical Teaching Hospital, Assuit Univeristy were used. Blood samples were taken monthly (from June 2018 to May 2019). Biometry of the testes and seminal glands have been considered clinically at the day of sampling.
Hormonal assay of testosterone : serum testosterone level was determined by using of testosterone Enzyme immunoassay (EIA) test Kit.
The obtained results of the current investigation were summarized as follows:
In group (І) slaughterhouse : the live body weight, scrotal circumference and testicular measurements (length, breadth, depth and volume) were increased with age. Moreover, there were significant differences (p ˂ 0.05) between scrotal circumference and age groups, also a significant differences between testicular measurements and age was present. On the other hand, differences in body weight was significant only between 1.5 – 1.8 yeas and 2 – 2.5 years. Statistically, significant positive correlation between testes volume (r = 0.732) and scrotal circumference (r = 0.875) with age was found at P˂ 0.01, also a significant positive correlation was reported between testes volume and scrotal circumference (r = 0.883, P˂ 0.01).
With regard to Seminal glands, it is found that the total seminal glands weight increased with the advancement of age. Positive correlation between total seminal gland weight with age was evident. The breadth, thickness and weight of both right and left seminal gland increased also. However, the length of the right seminal gland decreased with the progression of age, but the length of the left seminal gland decreased from 1.5-1.8 y to 2 – 2.5 y and reincreased again at 3 -4 years of age. Moreover, there is a slight differences between left and right seminal gland in the term of biometry.
A significant differences between seminal glands measurement and age was not present.
The fructose content of seminal glands (mg/gland) increased with the growths of seminal gland (weight) from 1.5 y to 4 years of age. Moreover, a minimum value of 12.49 mg /gland was recorded in 1.5 – 1.8 years, while the maximum value of 210 .45 mg /gland was recorded at 2 – 2.5 years of age. Positive correlation between total seminal gland weight and fructose concentration (mg/100g) was detected r = 0.72, also a highly positive correlation between total seminal gland weight and total fructose content of seminal gland (mg/gland) was evident (r=0.941, P˂0.01). However, no significant differences neither between average fructose content of seminal glands (mg/gland) nor fructose concentration per 1 g. tissue with age, were detected. In addition, it is noticed that the serum testosterone level was higher in te first group (1. 5 – 1.8 y), then a declination in their levels was recorded from 2 – 2.5 to 3 – 4 years of age. No significant difference between groups was found.
Negative correlations between testosterone concentration and age (r = -0.232 ), scrotal circumference (r = -0.214), testes volume (r= -0.152), total seminal gland weight (r = -0.142) and total fructose concentration per gland (r = - 0.156) were present, but not at a significant levels.
group ( П ) farm animal : It is obvious that live body weight increased linearly from 4 months to 84 months old. Significant difference between body weight and age in all groups was present (p ˂ 0.05) except between 6 months and 8 months was not at a significant level. Moreover, significant positive correlation(r = 0.933) between body weight and age among individuals were evident at P ˂ 0.01.
Furthermore, it is found that scrotal circumference increased from 4 months to 84 years old. Significant difference between scrotal circumference and age was existing (p ˂ 0.05), however, significant difference between 42-48 and 60-84 months was not present. Significant positive correlation between scrotal circumference and age among individuals (r = 0.983, P ˂ 0.01) was present.
On the other hand, testicular measurements (length, breadth, depth and volume) are increased with the advancement of age, significant difference between testicular measurements and age for all groups was present (p ˂ 0.05), except between 24 and 42-48 months and between 42-48 and 60-84 months of age for the length and depth. Moreover, no significant deferences were observed between 24 and 42 – 48 and between 12 and 18 months of age for breadth. However, a non significant difference in testis volume was present between 4 months and 6 months of age only.
Statistically, significant positive correlation between testes volume and age (r= 0.973) as well as between testes volume and scrotal circumference (r = 0.974) was evident at P ˂ 0.01.
With regard to testosterone concentrations, the obtained data revealed that serum testosterone level was very low at 4 months of age, then increased from 6 months till 48 months of age, followed by a decline in the levels of testosterone at 60-84 months of age. Significant differences between testosterone concentration and age was recorded between 42-48 months and all other groups, however, differences was significant between 60-84 months with all other groups, except at 24 months which was not at a significant value. No significant differences were recorded between 4, 6, 8, 12 and 18 months of age.
It is of interest to mentioned that a significant positive correlation between testosterone levels and age (r=0.654), live body weight (r= 0.65), scrotal circumference (r = 0.696) and testis volume (r = 0.716) among individuals were present.
group (Ш) seasonal effect on testosterone levels: It is clear that the higher mean testosterone concentration (1.72 ng/ml) was recorded in autumn, while the lowest average concentration (0.77 ng/ml) was recorded in winter. A maximum value of 4.45 ng /ml was reported in summer, whereas the minimum value of 0.13 ng/ml was recorded in winter. Moreover, testosterone concentrations were found to be higher in hot season than in cold season.
Statistically, there is no significant difference in testosterone levels between different seasons of the year as well as between hot and cold seasons.
As a major conclusion from the present work, testosterone profiles have direct correlations with the different aspects of reproduction in male buffaloes as mentioned. In addition, the vastus range of variations in serum testosterone profiles even in the same animal denotes the presence of many factors controlling its physiological role rather than the diurnal effects.
Moreover, the role of testosterone in controlling male reproduction is well known and thus, for accurate diagnosis many blood samples for hormone analysis should be considered.
Anyhow, the marked lower levels of this hormone in buffalo, than cattle this might reflect the comparatively lower sex drive of this species.