Swelum Ayman Abdel-Aziz, Ayadi Moez, Alhidary Ibrahim, Alowaimer Abdullah, Abouheif Mohamed
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.
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.
Theriogenology. 2017 Feb;89:79-85. doi: 10.1016/j.theriogenology.2016.10.013. Epub 2016 Oct 20.
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.
本研究使用了24只约6.5月龄的纳吉迪公羊来评估限饲和饲喂频率对瘦素和睾酮激素浓度、性行为及精液性状的影响。公羊被平均分为三个饲喂组。第一组作为对照组，自由采食。第二组和第三组按自由采食量的0.85进行限饲，分别每日饲喂一次（R1M）或两次（R2M）。在研究的第六、七、八周评估性行为和精液质量。在研究的第41、48和55天，于饲喂前1小时采集血样，以测定血清瘦素和睾酮浓度。所有羔羊在实验8周后屠宰。结果表明，限饲组的屠宰体重、平均日增重、干物质摄入量、内脏脂肪、尾脂、体脂厚度、体壁厚度和睾丸重量均低于自由采食组（P<0.01）；两种限饲处理的这些相应性状无差异。限饲公羊的瘦素浓度低于自由采食公羊（P<0.01），而睾酮浓度高于自由采食公羊（P<0.01）；R1M组和R2M组之间无差异。与对照组相比，限饲公羊的射精潜伏期较短（P<0.01），而性活跃公羊的比例和性欲评分不受限饲或饲喂频率的影响。限饲公羊的精子活力、前向运动能力和快速运动精子的百分比高于自由采食公羊（P<0.01）。与自由采食组相比，R1M公羊的直线度较高（P<0.01），曲线速度较低（P<0.01）。睾酮与精子活力和前向运动能力呈正相关（P<0.05），与脂肪测量值、瘦素和射精潜伏期呈负相关（P<0.04）。总之，适度的采食量限制可以优化公羊的体脂率和睾酮浓度，有助于改善一些繁殖性状。
