Seasonal variation in some reproductive parameters of male vicuña in the High Andes of northern Chile

Urquieta, Bessie; Cepeda, Raquel; Céceres, J.E.; Raggi, Luis A.; Rojas, José Rodrigo

doi:10.1006/jare.1994.1012

Cited by 14 publications

(10 citation statements)

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“…However, some males may not reach puberty even after age 3 years. [10][11][12] The increase in testosterone results in the development of male organs, particularly the sigmoidal flexure, which is absent in very young crias. 8,9 Endocrine Function of the Testicle Basal testosterone concentrations in llamas (60-90 picogram per milliliter [pg/mL]) are present in blood from birth to approximately age 20 to 21 months.…”

Section: Detachment Of the Penis-prepuce Adhesionmentioning

confidence: 99%

Reproductive Anatomy and Physiology in the Male

Bravo¹

2014

Llama and Alpaca Care

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Section: Detachment Of the Penis-prepuce Adhesionmentioning

confidence: 99%

Reproductive Anatomy and Physiology in the Male

Bravo¹

2014

Llama and Alpaca Care

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“…There are basic descriptions of the testicular anatomy and histology in the llama (for review see Smith et al, 1994) and of its spermatogenesis (Dhelon and von Lawzewitsch, 1987) and also of spermatogenesis and seasonal variations of histological and endocrine parameters in the vicuna (Urquieta et al, 1994; Bustos‐Obregón et al, 1997).…”

mentioning

confidence: 99%

Distribution of keratins, vimentin, and actin in the testis of two South American camelids: Vicuna(Vicugna vicugna)and llama(Lama glama). An immunohistochemical study

Rodríguez¹,

Rojas²,

Bustos‐Obregón³

et al. 1999

Anat. Rec.

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The purpose of the present study was to investigate the pattern of distribution of cytokeratins, vimentin and muscular actin in the testis of vicuna (Vicugna vicugna) and llama (Lama glama) two species of camelids native of the Andean high plateau of South America. Testicular biopsies of four vicunas and five llamas were used. Animals were healthy breeders. The tissues were processed by standard immunohistochemis-try with antipancytokeratin AE1/AE3, antikeratin 18 (K 18), CAM 5.2 (antikera-tin 5, 18, and 19), antivimentin, and smooth-muscle-specific antiactin antibodies to track the cytoskeletal pattern of testicular cells. Using AE1/AE3 antibody the immunostaining was found in the epithelial lining of tubuli recti and rete testis. The reaction was relatively stronger in the apical cytoplasm of epithelial cells. The testicular cells of the two species showed no reaction to K 18 and CAM 5.2 antibodies. Antivimentin antibody stained the basal cytoplasm of the Sertoli cells, the Leydig cells, and the epithelial lining of tubuli recti and rete testis. In the last two structures the immunostain was relatively more intense in the basal cytoplasm of epithelial cells. Antiactin antibody stained the peritubular cells and the muscle cells of the lamina propria of tubuli recti and rete testis. The presence in these species of only some keratins found in man, its coexpression with vimentin in epithelial lining of tubuli recti and rete testis and the peritubule organization, so different from other ungulates may reflect a differential adaptation of the cytoskeleton to particular reproductive strategies. Anat Rec 254:330-335, 1999. Vicuna (Vicugna vicugna) and llama (Lama glama) are two species of South American camelids inhabiting the Andean plateau over 3,500 m. of altitude. Though the llama plays an important economic role as domestic animal for the Andean natives, many facets of its reproductive biology, mostly in the male, are not known. The situation is even worse regarding the male vicuna, a wild camelid producer of high quality wool.

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“…In camels, the pattern of testosterone section is strongly affected by season and diurnal rhythms particularly in rutting camels ( 35 , 36 ). Seasonal effect of basal testosterone levels has also been described in the vicuña ( Vicugna vicugna ) ( 37 ) and the alpaca ( 3 ). In the vicuña, plasma testosterone concentration was higher in February (summer, peak breeding season) than in August (winter) and testis, seminiferous tubule and Leydig cell diameter were larger in February than in August.…”

Section: Discussionmentioning

confidence: 92%

“…In the vicuña, plasma testosterone concentration was higher in February (summer, peak breeding season) than in August (winter) and testis, seminiferous tubule and Leydig cell diameter were larger in February than in August. Spermatogenic activity was lower in Aug. than in Feb (37). In alpacas, Sumar in 1991 reported significantly higher serum testosterone concentration in spring (2 to 3 times higher than in other seasons) (38).…”

Section: Discussionmentioning

confidence: 99%

Basal Levels and hCG Responses of Serum Testosterone and Estrogen in Male Alpacas

2020

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Steroid response to human Chorionic Gonadotropin (hCG) administration has been used in various species to study testicular function and for diagnostic purposes. In this study, two experiments were conducted to determine serum testosterone concentration response to administration of hCG and its correlation with testicular weight. In the second experiment the relationship between age, testosterone and estrogen response to hCG, and testicular histometry was in pre-pubertal and post-pubertal male alpacas. For experiment 1, males in two age groups (2 to 3 years, n = 9) and (4 to 7 years; n = 15) received 3,000 IU hCG IV, 36 to 48 h before castration. Serum testosterone concentration was determined before (T0), 1 h (T1), 2 h (T2), 8 h (T8), and 24 h (T24) after administration of hCG. Basal concentrations of serum testosterone was significantly different ( P < 0.01) between age groups. Serum testosterone concentrations increased over time and doubled 2 h after treatment. The highest change (250 to 300% increase from T0) was observed at 8 h (3.5 ± 0.3 ng/ml). A significant correlation ( P < 0.01; r = 0.64) was found between serum testosterone concentration and total testicular weight. For experiment 2, 60 males ranging in age from 6 to 60 months were used. Serum testosterone and estrogen was determined in samples taken just prior to and 2 h after administration of 3,000 IU hCG. Basal serum testosterone concentrations were very low (≤0.1 ng/mL) until 9 months of age then increased steadily with age. There was a significant variation amongst males within the same age group. Serum testosterone concentration increased by 2- to 4-fold 2 h after hCG injection ( P ≤ 0.05). Males in the 13 to 14 months of age group had the highest rise. Estrogen concentration increased in response to hCG administration and was detected only in males with high testosterone. We conclude that administration of 3,000 IU of hCG IV can be used reliably to detect testicular tissue and study its steroidogenic activity. The response is correlated with testicular weight and Leydig cell number. Testicular growth and sensitivity to LH stimulation increases between the ages of 13 and 14 months. The aromatizing ability of Leydig cells increased significantly in post-pubertal male alpacas.

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Seasonal variation in some reproductive parameters of male vicuña in the High Andes of northern Chile

Cited by 14 publications

References 0 publications

Reproductive Anatomy and Physiology in the Male

Reproductive Anatomy and Physiology in the Male

Distribution of keratins, vimentin, and actin in the testis of two South American camelids: Vicuna(Vicugna vicugna)and llama(Lama glama). An immunohistochemical study

Basal Levels and hCG Responses of Serum Testosterone and Estrogen in Male Alpacas

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