日粮能量水平对绵羊睾丸发育和相关基因表达的影响

Effects of dietary energy levels on testis development and the expression of related genes in sheep

为探究日粮能量水平对初情期绵羊睾丸发育的影响,选取45只体重[(24.27±0.63) kg]相近的3月龄美利奴公羔,平均分成3组,每组15只,分别饲喂高(10.5 MJ·kg^(-1))、中(10.1 MJ·kg^(-1))、低(9.7 MJ·kg^(-1))3种能量水平日粮。经过104 d的饲养试验后每组随机选择10只羔羊屠宰,测定其睾丸大小、睾丸组织总抗氧化能力、谷胱甘肽过氧化物酶活性和睾酮水平,利用RT-qPCR方法检测与能量代谢和类固醇激素合成相关基因表达情况。结果表明不同能量水平日粮对羔羊体重[(51.73±0.56) kg,(50.69±0.55) kg,(51.51±1.03) kg]、睾丸重量[(253.60±19.69) g,(274.60±14.17) g,(262.40±19.91) g]、睾丸组织的总抗氧化能力[(10.59±1.13) U·mg^(-1)prot,(8.60±1.00) U·mg^(-1)prot,(7.86±1.73) U·mg^(-1)prot]、谷胱甘肽过氧化物酶活性[(0.28±0.08) U·mg^(-1)prot,(0.14±0.03) U·mg^(-1)prot,(0.23±0.03) U·mg^(-1)prot]和睾酮水平[(0.52±0.07) ng·mg^(-1)prot,(0.35±0.05)ng·mg^(-1)prot,(0.44±0.06) ng·mg^(-1)prot]均无显著影响(P>0.05),但是中能量水平组代谢相关基因IGF-1R和IGF-1以及类固醇激素合成相关基因CYP19A1和3βHSD的表达水平显著高于高能量水平组和低能量水平组(P<0.05)。综上所述,初情期羔羊日粮水平对睾丸能量代谢活动存在影响,中等能量水平日粮促进睾丸组织中代谢相关基因IGF-1R和IGF-1以及类固醇激素合成相关基因CYP19A1和3βHSD表达,但对睾丸发育无显著影响。

We investigated the effect of dietary energy levels on testicular development in sheep during the pre-puberty stage.Forty-five 3-month-old merino lambs with similar body weight[(24.27±0.63)kg]were randomly divided into three groups;namely high(10.5 MJ·kg^(-1)),medium(10.1 MJ·kg^(-1))and low(9.7 MJ·kg^(-1))energy level groups.After a feeding period of 104 days,10 lambs were randomly selected from each group for slaughter,and their testicular size,total antioxidant levels in testicular tissue,glutathione peroxidase activity,and testosterone levels were measured.The transcript levels of genes related to energy metabolism and steroid hormone synthesis were detected by RT-qPCR.The results indicated that the diets with different energy levels did not significantly affect body weight(51.73±0.56 kg,50.69±0.55 kg and 51.51±1.03 kg for high,medium and low energy level groups,respectively),testicular weight(253.60±19.69 g,274.60±14.17 g and 262.40±19.91 g,respectively),total antioxidant level(10.59±1.13 U·mg^(-1) prot,8.60±1.00 U·mg^(-1) prot and 7.86±1.73 U·mg^(-1) prot,respectively),glutathione peroxidase activity(0.28±0.08 U·mg^(-1) prot,0.14±0.03 U·mg^(-1) prot and 0.23±0.03 U·mg^(-1) prot,respectively),or testosterone level(0.52±0.07 ng·mg^(-1) prot,0.35±0.05 ng·mg^(-1) prot and 0.44±0.06 ng·mg^(-1) prot,respectively)in testicular tissue(P>0.05).However,the transcript levels of the metabolism-related genes IGF-1R and IGF-1 and the steroidogenesis-related genes CYP19A1 and 3βHSD were significantly higher in the middle energy level group than in the other two groups(P<0.05).In summary,dietary energy levels potentially affect testicular metabolic activity in sheep.Feeding lambs with a middle energy level diet during the pre-puberty stage promoted the expression of metabolism-and steroidogenesis-related genes,but did not significantly affect testicular development.