Nutritional management during fetal and postnatal life, and the influence on testicular stereology and Sertoli cell numbers in Corriedale ram lambs (original) (raw)
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Biometry and Testicular Growth Influenced by Nutrition on Prepubertal Pelibuey Lambs
The growth and testicular development was studied in 48 Pelibuey male lambs 76.6±3.0 days of age and 12.7±1.9 kg body weight (BW), two groups were designed (n=24). 1: Intensive rotational grassing (IRG), 2: Intensive rotational grassing plus nutritional supplement (IRGS). BW was recorded every 15 days from 75 days of age to the onset of puberty. The animals grazed on Panicum maximum. IRGS received a concentrate with 15% of protein. The testicular biometry included scrotal circumference (SC) and testicular volume (TV). Blood samples were collected each 15 days from 90 to 190 days of age for evaluate the testosterone concentrations. BW, SC and TV at histological puberty was higher in IRGS than IRG; 22.5±1.5 vs. 16.06±1.5 kg, 22.0±1.0 vs. 12.2±1.5 cm, 60.5±1.7 vs. 12±3.5 cm 3 respectively (P<0.05) with an average age for the two groups of 162±7.0 days. The correlation coefficient (R) was higher (P<0.05) for SC vs BW than age vs BW (0.884 vs 0.816) and the TV vs. BW than TV vs. age (0.849 vs. 0.777) in the IRGS; the IRG showed lower R for the same comparisons (P<0.05). Seminiferous tubules showed lumen by day 142, spermatids and spermatozoids by day 171 for IRGS, meanwhile in the IRG only showed gonocytes and Sertoli cells. Testosterone concentrations reached a peak (2.5 ng/ml) at 168 days of age for the IRGS meanwhile the IRG showed lower levels than 0.05 ng/ml. Testicular development and testosterone concentrations depends more on BW than age; and they are modified by the nutritional management in prepuberal male lambs.
Testicular development in male lambs prenatally exposed to a high-starch diet
Molecular reproduction and development, 2018
Maternal nutrition during critical gestation periods impacts on offspring in later life; effects of high-starch maternal diet on testicular development in lambs were addressed. Dairy ewes were fed diets providing either 27% (Starch, S) or 11% (Fiber, F) of starch from mating to lambing (∼147 days; S147, F147) or for the last 75 days of gestation (S75, F75). Testes of single male lambs were measured and then sampled for histological and gene expression analyses at selected ages. Testicular dimensions and weight were similar among groups, but the total area of seminiferous tubules increased with age and tended to be higher (p = 0.057) in lambs from starch- than fiber-fed ewes. Sertoli and germ cells number increased with age, but was not influenced by maternal diet. Transcript abundances of androgen receptor (AR), insulin-like growth factor 1 (IGF1), and hydroxysteroid (17-beta) dehydrogenase 3 (HSD17B3) was similar between S147 and F147 lambs (p > 0.1). Abundance of luteinizing ho...
TURKISH JOURNAL OF VETERINARY AND ANIMAL SCIENCES, 2016
The aim of this study was to investigate changes of serum testosterone, scrotal circumference, body weight, and semen characteristics in a Meat Institute Sheep (MIS) population during their developing period (between 3 and 17 months). Correlative relationships among parameters were also tested. Body weight and scrotal circumference were measured monthly, blood samples for testosterone levels were taken bimonthly (3-17 months), and semen samples were collected by an electroejaculator between the ages of 9 and 17 months. The analysis showed that the average serum testosterone levels ranged from 1.83 to 13.28 ng/mL and significantly depended on the age of the lambs (P < 0.05). The trend in the level of serum testosterone was characterized by pronounced variability throughout the study period. Changes in scrotal circumference and body weight were significantly dependent on age. Ejaculate volume, sperm motility, and the percentage of live spermatozoa increased with age, except for the percentage of abnormal spermatozoa, which decreased with age. Correlations among serum testosterone, scrotal circumference, and body weight were moderately to highly positive and highly significant. All parameters of semen quality were poorly correlated with testosterone and body weight, while scrotal circumference was in moderate correlation only with ejaculate volume and live sperm count (P < 0.05).
Effect of prenatal testosterone treatment on nitrogen utilization and endocrine status of ewe lambs
Journal of animal science, 1990
Thirty-eight pregnant Suffolk ewes were assigned randomly to a control group or implanted with approximately 2 g of testosterone propionate (TP) when they were between d 40 and 60 of gestation. Implants were removed 3 wk prior to lambing. Five ewe lambs born to implanted ewes and ten ewe lambs born to nonimplanted ewes were utilized in this experiment. Ram lambs were not used in this trial. No differences (P greater than .10) were observed for fecal, urinary and total N excretion and amount of N absorbed. Nitrogen retained (percentage of N intake and g/d) was higher (P less than .05) in prenatally androgenized ewe lambs than in control ewe lambs. Plasma insulin concentrations averaged 99% higher (P less than .05) in prenatally androgenized ewe lambs. Plasma insulin-like growth factor I (IGF-I) concentrations averaged 29% higher (P less than .06) in ewe lambs treated prenatally with testosterone. Nonesterified fatty acid (NEFA) concentrations averaged 41% higher (P less than .05) in ...
Low maternal nutrition during pregnancy reduces the number of Sertoli cells in the newborn lamb
Reproduction Fertility and Development, 2002
A journal for the publication of original work, review and comment in the field of reproductive biology, reproductive endocrinology and developmental biology, including puberty, lactation and fetal physiology when they fall within these fields Abstract. The nutritional status of females during pregnancy can play a critical role in the postnatal growth and development of the offspring, often leading to permanent changes ('fetal programming'). The Sertoli cells are a strong candidate for fetal programming of future performance because the number of Sertoli cells is highly correlated with adult testicular size and the maximum rate of sperm production. For Merino ewes, we imposed different levels of metabolizable energy (ME) intake (LowME: 70% of requirements for maintenance of ewe body mass and normal growth of conceptus (n = 13); HighME: 110% of those requirements (n = 12)) from Week 10 of pregnancy until parturition and then tested for effects on testicular histology in newborn males. Pregnant ewes were weighed weekly and lambs were weighed at birth and 2 days later. Blood was sampled at the same times. LowME ewes did not gain weight, whereas HighME ewes gained 17% over their pretreatment weight. Birthweights were higher in HighME lambs than in LowME lambs. Paired testes tended to be heavier in the HighME group than in the LowME group (P=0.08). The diameter of the testicular cords did not differ. The absolute volume of testicular cords (0.36 ± 0.02 v. 0.30 ± 0.02 mL for HighME v. LowME, respectively; P=0.03) and the number of Sertoli cells (43.0 ± 2.5 v. 34.5 ± 2.0 × 10 8 for HighME v. LowME, respectively; P=0.018) per testis were both greater in the HighME than in the LowME group. Plasma follicle-stimulating hormone concentrations were not significantly affected at birth or 2 days later. We conclude that undernutrition during pregnancy can reduce testicular development in the newborn. Depending on the ability of the Sertoli cell population to recover between birth and puberty, this may limit the ultimate number of Sertoli cells and, hence, the future capacity for sperm production and fertility.
South African Journal of Animal Science, 2007
The study was conducted to measure the development of several testicular characteristics and to investigate the relationship between testicular parameters with body growth, semen characteristics and serum testosterone levels in growing ram lambs. Seventeen single born Kivircik ram lambs from three to four year old ewes were used. When the rams were two months old measurements of the length, diameter and circumference of their testes and body weights started, and blood samples were collected at 20-day intervals for the next 12 months. From seven to 14 months of age semen was collected at monthly intervals. There was a gradual and linear increase in testicular dimensions from two to 11 months of age. A rapid increase in all testicular dimensions was observed between 140 to 160 days of age. All measurements of testes, live weight, age and serum testosterone concentrations were positively and significantly correlated with each other. While a significant positive correlation was found at seven and eight months of age between all testicular measurements and semen volume and motility, no such correlations were observed between nine and 14 months of age. From seven to 14 months of age no correlation was measured between serum testosterone concentrations and spermatological characteristics. These results demonstrated that testicular measurements, especially scrotal circumference, can be used as criteria for early selection of ram lambs to be used in breeding at relatively young ages.
Postnatal testicular development and testosterone changes in Ghezel ram lambs
This study was conducted to investigate the histological structure of testis and hormonal changes during prepubertal Ghezel ram lambs. Histometrical evaluation of the testis was performed in 36 Ghezel lambs from one to 9 months of age. Lambs were allotted into nine groups, and surgically castrated each month from 1 to 9 months of age (n = 4 lambs per group). In addition, blood samples were taken from six animals from 1 month of age to adulthood to measure plasma levels of testosterone. With the age held constant, scrotal circumference and body weight were correlated (r = 0.960, P < 0.01). The sex cords did not have lumen up to the age of 4 months and lumenization process was completed after 8 months of age. A dramatic increase in spermatogonia cells per cross-section of seminiferous tubule was observed from 3 to 5 months of age; their number per tubule cross-section stabilized after 8 months. Spermatogenesis started when the spermatocyte cells were observed at the 4th month, and established at 8 months of age (body weight = 42.39 kg, scrotal circumference = 25.8 cm). Onset of puberty was observed to be established at 8 months of age when spermatozoa, adhered to the adluminal border of the Sertoli cells as well as in the tubular lumen. Leydig cells were visible in 4-month-old lambs. During the 5 months after birth, Leydig cell number showed a similar pattern as that observed for testosterone plasma levels. At 8–9 months of age the testosterone plasma level reached up to 2 ng/ml which contributed to the increase in testicular testosterone secreting capacity of the mature adult Leydig cells, with the accomplishment of this transition, sexual puberty is completed. It can be concluded that establishment of spermatogenesis begins a long time before puberty in 8 month-old Ghezel lambs.
Animal Reproduction Science, 2015
This experiment was conducted to investigate the effect of plane of nutrition on body weight, average daily gain, dry mater intake, semen characteristics, serum testosterone concentration and testicular circumference of Sanjabi ram lambs during the natural breeding season. Sanjabi ram lambs (n = 20) that were 8 months of age were penned under natural photoperiod at latitude 34 º 18´ N for a period of 9 months. The control group (C, n = 10) received a diet consisting of 80% alfalfa and 20% concentrate, providing 2.18 Mcal metabolizable energy and 130.0 g/kg DM crude protein, whereas, treatment group (T, n = 10) was fed with 65% alfalfa and 35% concentrate, providing 2.34 Mcal metabolizable energy and 160.0 g/kg DM crude protein. Body weight, additive daily gain and feed intake in T group were significantly greater than those obtained in C group. Body weight and testicular circumference increased at a steady rate throughout the experiment. All semen variables (except percentage of abnormal sperm and semen pH), serum testosterone concentration and testicular circumference were positively influenced A C C E P T E D M A N U S C R I P T by nutritional state (P < 0.05). Interaction of nutritional state with season was found for semen volume, sperm concentration and abnormal sperm, but there was no interaction on the total sperm, progressive motility, live sperm, semen pH and semen index. It is concluded that the reproductive activity of growing Sanjabi ram lambs is affected by nutritional state. These results also demonstrated a monthly pattern in reproductive characteristices of Sanjabi ram lambs, independent of the nutritional state.
Impact of Pre-pubertal Growth Rate on Pubertal Characteristics of Sohagi Ewe Lambs
Journal of Animal and Poultry Production
This study aimed to investigate the impact of pre-pubertal growth rate on pubertal characteristics of Sohagi ewe lambs. Thirty of Sohagi ewes lambs at 6-7 months of age were divided into three equal groups (n=10 per each group) according to its previous growth rate from birth to 6 months of age, groups marked as fast, medium and low growing. All groups were housed in closed barns with access to an open area and got their nutritional requirements depending on their growth stage. Results show that the pubertal characteristics of Sohagi ewe lambs at puberty were significantly affected (P<0.05) by the pre-pubertal growth rate. Ewe lambs in the fast-growing group were achieved to onset puberty firstly at 235 days on average then ewe lambs in the medium and low-growing group (242.6 and 269.4 days, respectively). Ewe lambs in the fast-growing group were the heaviest at puberty than ewe lambs in the medium and low-growing group (26.4 vs. 23.7 and 22.4 kg, respectively). Blood progesterone concentration was not significantly different among ewe lambs groups (1.419± 0.04 ng/ml on average, ranged from 1.203 to 1.737 ng/ml). In conclusion, results showed that the pre-pubertal growth rate of ewe lambs is one of the most influential factors affecting the development of puberty characteristics.
Small Ruminant Research, 2001
Ninety-six Awassi ram lambs, aged 2±3 months, raised and managed under a semi intensive system were used to measure development of testicular length, width, circumference and volume, and their association with development of body growth. The effects of parental size, age and body weight of lambs, production line (dairy or meat), type of birth and weight at birth and weaning on development of the four testicular parameters from weaning at 2±17 months of age were investigated. No signi®cant differences were observed between measurements of the left and right testis. The highest increase in testicular parameters occurred between 7 and 10 months of age at 34.6 kg live body weight. Only parental size, age and body weight affected testicular growth (P`0X05). Measurements of testes were correlated (P`0X01) with each other (r 0X68±0.97). They increased progressively and were correlated with body weight more than with age.