Biometric and Morphometric Characteristics of Turkey Testes in Bangladesh

Background : This study aimed to conduct a macro-morphometric evaluation of the primary reproductive organs, specifically the testes, in Turkey tom. Methods : Twelve healthy, mature birds, with weights ranging from 5.450±0.12 kg to 7.570±0.51 kg, and ages between 28 weeks and 48 weeks, were sourced from the SMA Organic Agro Farm in Belgari and surrounding turkey farms in the Sherpur upazilla of Bogura district. Testicular measurements were performed along with their macroscopic description. Results: The testes were found on the sides of the body's midline, underneath the kidneys, and at the back of the lungs. At 28 weeks of age, the turkey tom's testes were measured. The left testis had a length of 3.74±22.38 cm, width of 2.08±2.63 cm, thickness of 1.87±5.93 cm, and weighed 9.50±12.01 gm, while the right testis measured 3.55±4.50 cm in length, 1.95±2.48 cm in width, 1.58±1.99 cm in thickness, and weighed 7.83±9.91 gm. The average live body weight at this stage was 5.670±7.17 kg. At 48 weeks old, the turkey tom weighed around 7.800±9.86 kg. The left testis measured about 4.15±5.26 cm in length, 2.40±9.29 cm in width, 1.92±5.92 cm in thickness, and weighed approximately 10.50±13.28 gm. On the other hand, the right testis was around 3.57±4.51 cm long, 2.04±2.58 cm wide, 1.72±2.18 cm thick, and weighed about 9.33±11.80 gm. Conclusions : our study shows that as the Turkey tom grows up, its testes change in size and weight. We noticed that the left testis is consistently bigger and heavier than the right one. This suggests that the left testis gets larger as the turkey tom gets older. The reason for such differences could be explored in future research.


Introduction
Poultry rearing has gained popularity in recent years in Bangladesh, particularly turkey farming. Turkeys are favored due to their size, ease of handling, rapid growth rate, adaptability, disease resistance, low mortality, cost-effective feeding, and high market value (Asaduzzaman et al., 2017). This emerging livestock subsector significantly contributes to Bangladesh's economic growth. Turkey, a large poultry species originally from America and domesticated by Indian tribes (Becker, 2006), thrives well in arid conditions, tolerates heat, roams extensively, and yields high-quality meat (Yakubu et al., 2013). Turkeys are excellent insect foragers and can aid in pest control for crops (Grimes et al., 2007). The demand for lean and flavorful turkey meat has grown compared to broiler meat (Karki et al., 2005), addressing protein needs and consumer preferences.
Reproduction is vital for species continuity. Livestock reproductive systems engage during sexual maturity (Murphy, 2012). Male turkeys, like other birds, possess reproductive organs, including paired testes, deferens leading to the cloaca, and a copulation tool called a phallus (Yahaya, 2017). Testes generate spermatozoa within seminiferous tubules for fertilization (Wei, 2011), alongside producing testosterone aiding sperm production (Kelly, 2013). In poultry, testes lie in the abdominal cavity, anterior to kidneys, posterior to lungs, and encased in fibrous tissue (Elbajory, 2013).

Materials and Methods
This research was conducted at the Laboratory of the Department of Anatomy and Histology, Faculty of Veterinary and Animal Sciences, Hajee Mohammad Danesh Science and Technology University. The study utilized testicular samples from 12 male turkeys (Meleagris gallopavo) sourced from the SMA Organic Agro Farm in Belgari and surrounding turkey farms in the Sherpurupazilla of Bogura district. The samples were categorized into two age groups: 28 weeks (after the finisher phase) and 48 weeks (considered sexually mature stage) old turkeys. Each group comprised 6 male turkeys.
The live body weight of all turkey toms was measured using a digital weight machine (RFL Weight Scale). Six turkey toms from each age group were sacrificed for the study. Both testes were carefully extracted, trimmed of excess tissue, and collected. The length, width, and thickness of the testes were measured using Vernier slide calipers. Additionally, the weight of the testes was recorded using an electronic balance (RFL Weight Scale). For statistical analysis, all data were presented as mean ± standard error (SE), and analysis of variance was conducted using SPSS software (version 15) to assess differences.

Results and Discussion
The study revealed that the testes shape in Turkey tom was bean-shaped, positioned bilaterally on the lateral sides of the body's midline, beneath the kidneys on the ventral surface, and behind the lungs within the abdominal cavity of the turkey toms (Figure 1a). In a study involving Japanese quail, the testes were found as paired tubular organs enclosed by peritoneal covering within the body cavity (AI-Tememy et al., 2010; Kannan et al., 2015). Another study mentioned that in male birds, the testes are a pair of organs situated along the dorsal body wall (Kirby et al., 2000). It was noted that the left testis was positioned more anteriorly than the right one. A different study (Kigir et al., 2010) discovered that the left testis was generally higher and larger than the right one in pigeons.    Elbajory et al. (2013) in ducks. However, the mean weight of the right testis in turkey toms was lower than that of the left testis in our research.

Conclusion
Our study shows that as the Turkey tom grows up, its testes change in size and weight. We noticed that the left testis is consistently bigger and heavier than the right one. This suggests that the left testis gets larger as the turkey tom gets older. This could mean there is something special happening on the left side, and it would be interesting to find out why this is the case.