title: The relationships between body fatness, leptin, testosterone, and reproductive performance in ram lambs as affected by level and frequency of feeding.
abstract: This study was carried out using 24 Najdi ram lambs of approximately 6.5 months old to evaluate the effects of feed restriction and frequency of feeding on hormone concentrations of leptin and testosterone, sexual behavior, and semen traits. Ram lambs were allotted equally into three feeding groups. The first group was used as a control and fed ad libitum. The second and third groups were restricted fed at 0.85 ad libitum and fed either once (R1M) or twice daily (R2M). Sexual behavior and semen evaluation were assessed during the sixth, seventh, and eighth weeks of the study. Blood samples were drawn at 1-hour pre-feeding on days 41, 48, and 55 of the study for the determination of serum leptin and testosterone concentrations. All lambs were slaughtered after 8 weeks of experimentation. Results showed that the restricted-fed groups had lower (P < 0.01) values for slaughter body weight, average daily gain, dry matter intake, internal fat, tail fat, body fat thickness, body wall thickness, and testes weight than the ad libitum group; these corresponding traits did not differ between both restricted-fed treatments. Leptin and testosterone concentrations in restricted-fed rams were (P < 0.01) lower and higher, respectively, than in the ad libitum rams; there were no differences between R1M and R2M groups. The restricted-fed rams had lower (P < 0.01) ejaculation latency time compared with control, whereas the percentage of sexually active rams and sexual desire score were not affected by feeding restriction or frequency of feeding. Sperm motility, progressive motility, and percentage of sperm moving at rapid speed were higher (P < 0.01) in feed-restricted rams than in the ad libitum rams. R1M rams had higher (P < 0.01) value for straightness and lower (P < 0.01) value for curvilinear velocity in comparison with the ad libitum group. Testosterone was correlated positively (P < 0.05) with sperm motility and progressive motility and negatively (P < 0.04) with fat measurements, leptin, and ejaculation latency time. In conclusion, moderate intake restriction can optimize body fatness and testosterone concentrations in rams, which helped to improve some reproductive traits.
authors.affiliation: Department of Animal Production, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia; Department of Theriogenology, Faculty of Veterinary Medicine, Zagazig University, Sharkia, Egypt. Electronic address: aymanswelum@yahoo.com.
authors.forename: Ayman Abdel-Aziz
authors.initials: AA
authors.lastname: Swelum
authors.affiliation: Department of Animal Production, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia; Département de Biotechnologie Animale, Institut Supérieur de Biotechnologie de Beja, Université de Jendouba, Beja, Tunisia.
authors.forename: Moez
authors.initials: M
authors.lastname: Ayadi
authors.affiliation: Department of Animal Production, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Alhidary
authors.affiliation: Department of Animal Production, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Abdullah
authors.initials: A
authors.lastname: Alowaimer
authors.affiliation: Department of Animal Production, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Abouheif
mesh_terms: D000273:Adipose Tissue / Q000502:physiology*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001835:Body Weight; D004542:Ejaculation / Q000502:physiology; D020738:Leptin / Q000097:blood*; D008297:Male; D012098:Reproduction; D055101:Semen Analysis; D012726:Sexual Behavior, Animal / Q000502:physiology*; D034561:Sheep, Domestic / Q000502:physiology*; D013081:Sperm Motility / Q000502:physiology; D013737:Testis / Q000033:anatomy & histology; D013739:Testosterone / Q000097:blood*
chemical_list: D020738:Leptin; D013739:Testosterone
keywords: Fatness; Feeding; Leptin; Libido; Ram Semen; Testosterone