生长激素释放肽-2对DLY生长猪生产性能和蛋白质利用的影响

Effect of GH-releasing Peptide-2 on Growth Performance and Protein Utilization in Growing Pigs

将10头初始体重为(26.55±1.36) kg 的DLY生长猪平均随机分成对照组和处理组,处理组连续15 d每天每头猪按体重分别肌肉注射30 μg/kg的GHRP-2,对照组注射同体积生理盐水,考察GHRP-2对试猪生产性能和蛋白质利用及GH水平的影响.停止给药后,再进行15 d的生长实验,考察停药后试猪生产性能的变化情况.在给药期,与对照组相比,处理组试猪的日增重除1～5 d增加了7%以外,其余阶段有所下降(P＞0.05),F/G除1～5 d降低了11.1%外、其余阶段均有所上升,采食量变化不明显;第6～10天处理组试猪的蛋白质的利用也有所下降(P＞0.05),其中NPU降低8.5%(P=0.01);第7～8天的蛋白质的合成,降解和净沉积速率在数值上也有所降低(P＞0.05);第15天,GHRP-2促进了GH的释放,其中处理组平均GH水平显著高于对照组(P=0.01),血清尿素N和总蛋白在数值上分别降低和增加(P＞0.05).在停止给药的5 d、10 d和15 d内处理组日增重分别增加16.85%、10.23%、1.11%,F/G分别降低13.7%、8.82%、5.51%,差异均不显著,采食量几乎没有变化.总之,本实验研究表明:肌肉注射GHRP-2对DLY生长猪的生产性能和蛋白质利用没有改善作用,但前期注射的GHRP-2对试猪后续生产性能有改善的趋势.

10 DLY growing pigs at （26.55 ± 1.36） kg of mean body weight were allocated into control and treatment group randomly and the treatment pigs were injected with GHRP- 2 intramuscularly at the dose of 30 μg/kgBW respectively every day for 15 days to investigate the the growth performance and protein utilization, then to investigate the growth performance in the following 15 days without injection. Compared with the control pigs, the average daily gain of treatment pigs increased by 7% during the period from day 1 to day 5 and decreased in the following treatment days （P〉0.05）, the F/G of treatment pigs decreased by 11.1% during the period from day 1 to day 5 and increased in the following treatment days （P〉0.05）, there was no remarkable effect on the daily feed intake; protein utilization from day 6 to day 10 was reduced （P〉0.05） ; and the net protein utilization decreased 8.5% （P = 0.01 ） in this period. The protein synthesis, protein breakdown and the protein net utilization decreased numerically during the period from day 7 to day 8. On the 15th day, the GH was stimulated by GHRP - 2 and significantly increased （P =0.01） in terms of means in treatment pigs. The urea nitro- gen and total protein of serum decreased and increased numerically respectively （P 〉0.05）. During the period of stopping GHRP-2 treatment, compared with the control pigs, the average daily gain of treatment pigs increased by 16.85%, 10.23%, 1.11% in the first 5 days, the first 10 days and the whole 15 days respectively, the F/G of treatment pigs decreased by 13.7%, 8.82%, 5.51% in the first 5 days, the first 10 days and the whole 15 days respectively, the daily feed intake had nearly no change. In conclusion, GHRP-2 treatment nearly had no improvement on the average daily gain and protein utilization of DLY growing pigs, but it may have the subsequent effect to the pigs during the period of stopping GHRP-2 treatment.