Sperm Production Rates

Amann, R. P.

doi:10.1016/b978-0-12-386601-1.50013-5

Cited by 200 publications

(180 citation statements)

References 91 publications

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“…This presumably enables males to replenish sperm reserves more quickly, and thus maintain higher mating rates or larger ejaculate sizes. Hence, while testis size is a useful predictor of sperm production rate (Amann 1970;Møller 1989), there is also increasing evidence both from comparative analyses (Schärer et al 2008;Lü pold et al 2009; this study) and experimental studies of sperm production plasticity (Oppliger et al 1998;Bjork et al 2007;Schärer & Vizoso 2007;Ramm & Stockley 2009), that factors within the testis contributing to variation in sperm production rate should also be considered in the context of male adaptations to sperm competition.…”

Section: Discussionmentioning

confidence: 89%

“…Increases in relative testis size are assumed to reflect increased investment in sperm production, since there is evidence for a correlation between testis size and the number of sperm produced per unit time (e.g. Amann 1970;Møller 1989). However, this assumption potentially masks important additional sources of variation in sperm production rate.…”

Section: Introductionmentioning

confidence: 99%

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Sperm competition and sperm length influence the rate of mammalian spermatogenesis

Ramm

Stockley

2009

Biol. Lett.

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Sperm competition typically favours an increased investment in testes, because larger testes can produce more sperm to provide a numerical advantage in competition with rival ejaculates. However, interspecific variation in testis size cannot be equated directly with variation in sperm production rate-which is the trait ultimately selected under sperm competition-because there are also differences between species in the proportion of spermatogenic tissue contained within the testis and in the time it takes to produce each sperm. Focusing on the latter source of variation, we provide phylogenetically controlled evidence for mammals that species with relatively large testes (and hence a high level of sperm competition) have a shorter duration of the cycle of the seminiferous epithelium and consequently a faster rate of spermatogenesis, enabling males to produce more sperm per unit testis per unit time. Moreover, we identify an independent negative relationship between sperm length and the rate of spermatogenesis, such that spermatogenesis takes longer in species with longer sperm. We conclude that sperm competition selects for both larger testes and a faster rate of spermatogenesis to increase overall sperm production, and that an evolutionary trade-off between sperm size and numbers may be mediated via constraints on the rate of spermatogenesis imposed by selection for longer sperm.

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Section: Discussionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Sperm competition and sperm length influence the rate of mammalian spermatogenesis

Ramm

Stockley

2009

Biol. Lett.

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“…We combined this treatment with the mature Merino ram, an animal that showed rapid, repeatable testicular responses to changes in food supply at all times of the year. Finally, we are able to use the strong linear relationship between testicular size and the rate of production of spermatozoa to estimate the gametogenic potential of the testis (Amann, 1970;Knight, 1977).…”

Section: Physiological Mechanismsmentioning

confidence: 99%

Interactions between nutrition and reproduction in the management of the mature male ruminant

Martin¹,

Blache²,

Miller³

et al. 2010

Animal

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In mature male sheep and goats, changes in feed intake seem to have little effect on gonadal endocrine function but induce profound changes on sperm production. These outcomes are due to changes in size of the seminiferous tubules and in spermatogenic efficiency. Except with severe underfeeding, there are only minor changes in the endocrine function of the testis (testosterone production) unless season-long treatments are imposed. For cattle, nutrition clearly affects testicular development and the production of spermatozoa in young bulls, as it does in other species but, after the period of rapid growth has ended, there appears to be little or no response to nutrition. We are developing a clear picture of the metabolic signals, neuroendocrine processes and hormonal control systems that are involved, particularly for the mature male sheep. The energetic components of the diet, rather than protein, seem to be responsible, so we have envisaged a model of the relationship between energy balance and reproduction that has 4 'dimensions': genotype, structure (organs), communication (chemical and neural signals, nutrient sensing) and time (dynamics, metabolic memory, programming). We have linked these perspectives to 'resource allocation theory' and incorporated them into strategies for 'clean, green and ethical animal production'. In contrast to the clear outcomes with respect to spermatogenesis, the effects of nutrition on sexual behaviour are more difficult to define, perhaps because the behaviour is affected by a complex mix of physiological factors and because of flawed methods for quantifying male behaviour. For example, sexual behaviour is compromised by severe feed restriction, but male sexual behaviour requires intensive motor activity so a decline in libido could be caused by general weakness rather than specific nutritional limitations. The interaction between sexual activity and feeding behaviour also complicates the issue under field conditions. At the other end of the scale, overweight males can show reduced sexual success because they have difficulty courting and mounting. For this reason, exercise can enhance the fertilising capacity of rams. This will be important in extensive mating systems where males need to assemble and guard a harem and then mate many times for several weeks. For artificial insemination centres, there seems to be very few data on the nutritional management of males, but problems with overfed animals appear to be a risk. Future research should concentrate on the intra-testicular systems mediating the effects of nutrition on the production of spermatozoa.

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“…Therefore, the testicular width has a great relationship with testicular weight, volume and length and can be used as an indicator for other testicular biometric characteristics (Martins, 2006). The testicular volume, related to the testis weight, is an important variable to assess the ability of sperm production (Amann, 1970).…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, testicular dimensions are important parameters in andrological evaluation and provide information that allows assessment of the normality of these organs and the ability of sperm production (Amann, 1970;France & Russell, 1998).…”

Section: Introductionmentioning

confidence: 99%

Corporal and testicular biometry in wild boar from birth to 12 months of age

et al. 2013

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RESUMO Biometria corporal e testicular de javalis do nascimento aos 12 meses de idadeObjetivou-se, com esta pesquisa, investigar o desenvolvimento testicular e corporal de javalis (Sus scrofa scrofa), do nascimento aos 12 meses de idade, avaliando-se, em cada faixa etária, o peso corporal, o desenvolvimento biométrico dos testículos e o índice gonadossomático (IGS). Utilizaram-se 52 javalis machos, provenientes de um criatório comercial, devidamente regulamentado pelo IBAMA. Os animais foram pesados e divididos em 13 grupos experimentais; os testículos foram coletados por orquiectomia unilateral e, em seguida, pesados em balança analítica e mensurados comprimento, largura e espessura. Os valores de peso corporal e as medidas testiculares foram crescentes, após o nascimento, sendo sua variação mais acelerada no primeiro mês e aos nove meses. Inicialmente, o padrão de crescimento testicular, do nascimento aos nove meses de idade, acompanhou o crescimento corporal e o índice gonadossomático variou de 0,07 a 0,09%. Em seguida, entre nove e 11 meses, o valor de crescimento testicular foi superior ao de crescimento corporal e o índice gonadossomático variou de 0,09 a 0,16%. Por fim, após os 11 meses de idade, os valores crescimento corporal e dos testículos voltaram a se comportar de forma semelhante. Conclui-se que o desenvolvimento do peso corporal, a biometria testicular e o IGS tiveram crescimento mais acelerado aos nove meses de idade.Palavras-chave: peso corporal, índice gonadossomático, desenvolvimento testicular, Sus scrofa scrofa. Received: 17/07/2009; Accepted: 27/12/2012 Corporal and testicular biometry in wild boar from birth to 12 months of ageThe aim of this tudy was to evaluate corporal and testicular development in wild boars (Sus scrofa scrofa) from birth to 12 months of age, evaluating body weight, biometric testicular parameters, and gonadosomatic index. Thirty-nine male wild boars from a commercial farm licensed by IBAMA were used in the study. The animals were weighed and assigned to 13 experimental groups. The testes were recovered through unilateral orchiectomy, weighed on an analytical balance and measured for length, width and thickness. Body weight and testicular measures increased with the age, up to 12 months, and were more accelerated in the first and ninth months. Initially the testicular growth pattern, between zero and nine months, followed the body growth, and the gonadosomatic index varied from 0.07 to 0.09%. Between 9 and 11 months, the testicular growth was superior to the body growth, and the gonadosomatic index varied from 0.09 to 0.16%. Finally, after 11 months of age, testicular and body growth had a similar behavior. In conclusion, body weight, testicular biometry, and gonadosomatic index development accelerated in the ninth month.

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Sperm Production Rates

Cited by 200 publications

References 91 publications

Sperm competition and sperm length influence the rate of mammalian spermatogenesis

Sperm competition and sperm length influence the rate of mammalian spermatogenesis

Interactions between nutrition and reproduction in the management of the mature male ruminant

Corporal and testicular biometry in wild boar from birth to 12 months of age

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