Endocrine Control of Testicular Development and Initiation of Spermatogenesis in Bulls

Brito, Leonardo F.C.

doi:10.1002/9781119602484.ch5

Cited by 2 publications

(1 citation statement)

References 50 publications

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“…Spermatogenesis is influenced by many factors including metabolic and endocrine status [ 11 ]. The brain–adrenal axis is involved in metabolic homeostasis [ 12 ] and it also influences the brain–gonadal axis [ 13 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

Incorporation of Testicular Ultrasonography and Hair Steroid Concentrations in Bull Breeding Soundness Evaluation

Cotticelli

Navas

Calabria

et al. 2023

Veterinary Sciences

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Testicular ultrasonography and steroid concentrations (cortisol, dehydroepiandrosterone sulfate (DHEA-S), cortisol/DHEA-S ratio, testosterone) in hair were examined for their utility in the bull breeding soundness evaluation (BBSE). Beef and dairy bulls (n = 16; 2.7 ± 0.4 years old; body condition score 3.2 ± 0.1) of five breeds were maintained under the same conditions at an accredited semen collection center. Bulls underwent routine semen collection twice weekly for 12 weeks and semen was processed and cryopreserved. Ultrasonography and hair sampling were undertaken at the last semen collection. Bulls with homogeneous testicular parenchyma (n = 8) had a higher (p < 0.05) percentage of motile sperm post-thawing compared with bulls with heterogeneous parenchyma (n = 8). There were no differences (p > 0.05) in the hair concentrations of cortisol, DHEA-S, and testosterone between bulls with homogeneous and heterogeneous parenchyma. In bulls with homogeneous parenchyma, hair DHEA-S concentration was positively correlated with percentage motile sperm (R2 = 0.76), progressively motile sperm (R2 = 0.70), and motility yield (R2 = 0.71). The findings indicate that the integration of testicular ultrasonography and hair DHEA-S status in the BBSE could provide a more comprehensive assessment of indicative fertility in bulls. Additionally, ultrasonography can be used in the BBSE when the evaluation of semen parameters is not available.

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Section: Introductionmentioning

confidence: 99%

Incorporation of Testicular Ultrasonography and Hair Steroid Concentrations in Bull Breeding Soundness Evaluation

Cotticelli

Navas

Calabria

et al. 2023

Veterinary Sciences

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Role of early life nutrition on the hypothalamic-pituitary-testicular axis of the bull

et al. 2018

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The objective of this study was to examine the effect of nutrition during the first 18 weeks of life on the physiological and transcriptional functionality of the hypothalamic (arcuate nucleus region), anterior pituitary and testes in Holstein–Friesian bull calves. Holstein–Friesian bull calves with a mean (±s.d.) age and bodyweight of 19 (±8.2) days and 47.5 (±5.3) kg, respectively, were assigned to either a HIGH (n = 10) or LOW (n = 10) plane of nutrition, to achieve an overall target growth rate of 1.2 or 0.5 kg/day, respectively. At 126 ± 1.1 days of age, all calves were euthanised. Animal performance (weekly) and systemic concentrations of metabolic (monthly) and reproductive hormones (fortnightly) were assessed. Testicular histology, targeted gene and protein expression of the arcuate nucleus region, anterior pituitary and testes were also assessed using qPCR and immunohistochemistry, respectively. The expression of candidate genes in testicular tissue from post pubertal 19-month-old Holstein–Friesian bulls (n = 10) was compared to that of the 18-week-old calves. Metabolite and metabolic hormone profiles generally reflected the improved metabolic status of the calves on the HIGH (P < 0.001). Calves offered a HIGH plane of nutrition were heavier at slaughter (P < 0.001), had larger testes (P < 0.001), larger seminiferous tubule diameter (P < 0.001), more mature spermatogenic cells (P < 0.001) and more Sertoli cells (P < 0.05) in accordance with both morphological and transcriptional data. Overall, testicular gene expression profiles suggested a more mature stage of development in HIGH compared with LOW and were more closely aligned to that of mature bulls. Ghrelin receptor was the only differentially expressed gene between LOW and HIGH calves in either the anterior pituitary (P < 0.05) or arcuate nucleus region of the hypothalamus (P < 0.10) and was upregulated in LOW for both tissues. This study indicates that an enhanced plane of nutrition during early calfhood favourably alters the biochemical regulation of the hypothalamus–anterior pituitary–testicular axis, advancing testicular development and hastening spermatogenesis.

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Endocrine Control of Testicular Development and Initiation of Spermatogenesis in Bulls

Cited by 2 publications

References 50 publications

Incorporation of Testicular Ultrasonography and Hair Steroid Concentrations in Bull Breeding Soundness Evaluation

Incorporation of Testicular Ultrasonography and Hair Steroid Concentrations in Bull Breeding Soundness Evaluation

Role of early life nutrition on the hypothalamic-pituitary-testicular axis of the bull

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