不同氨基酸水平的低蛋白质饲粮对后备母猪初情日龄、血清代谢产物和激素浓度的影响

Effects of Different Dietary Amino Acid Levels on Age of Puberty,Serum Metabolites and Hormone Concentration of Replacement Gilts Fed Low Protein Diets

本研究旨在理想氨基酸模式下,探讨不同氨基酸水平的低蛋白质饲粮对后备母猪初情日龄、血清代谢产物和激素浓度的影响。选用96头体貌相近、平均体重为(69.01±3.43)kg的长白×大白杂交后备母猪,随机分成4个组,每个组4个重复,分别饲喂4种不同可消化赖氨酸(DLys)水平的低蛋白质饲粮,并通过添加合成氨基酸保证4组饲粮中可消化赖氨酸、可消化含硫氨基酸、可消化苏氨酸和可消化色氨酸的值一致。70~100kg阶段,饲粮DLys水平为0.61%(组1)、0.66%(组2)、0.71%(组3)、0.76%(组4);100~125kg阶段,饲粮DLys水平为0.55%(组1)、0.60%(组2)、0.65%(组3)、0.70%(组4)。结果表明,增加饲粮DLys水平显著提高血清中赖氨酸(Lys)浓度,对血清甘油三酯(TG)和葡萄糖(GLU)浓度的影响不显著(P>0.05);血清胰岛素(INS)、胰岛素样生长因子-I(IGF-I)、促黄体素(LH)和雌二醇(E2)浓度随饲粮DLys水平的增加而提高,试验组3达到最高值(P>0.05),之后随DLys水平的增加而降低,试验组3血清INS浓度显著高于试验组1(P<0.05);后备母猪背膘厚和发情率随着饲粮DLys水平的增加呈现先升高后降低的趋势(P>0.05),初情日龄试验组3比试验组4显著提前(P<0.05)。综上表明,在理想氨基酸模式下,长大后备母猪70~100kg阶段和100~125kg阶段饲粮DLys适宜日摄入量分别为17.82和17.29g·d^(-1),即饲粮DLys水平分别为0.71%和0.65%时,有利于提高后备母猪血清代谢激素INS、IGF-I和生殖激素LH、E_2的浓度,缩短初情期日龄,提高发情率。

The experiment was conducted to investigate the effects of different amino acid levels in low crude protein dites on age of puberty, serum metabolites and hormone concentration of replacement gilts based on ideal dietary amino acid pattern. 96 Landrace×Large White gilts, with initial body weight of （69.01±3.43） kg and similar body conditions, were allocated to 4 groups with 4 replicates per group. The gilts were fed respectively with 4 low-protein diets with different digestible lysine（DLys） levels of 0.61%（group 1）, 0.66%（group 2）, 0.71%（group 3）, 0.76%（group 4） for the early phase（70 to 100 kg） and 0.55%（group 1）, 0.60%（group 2）, 0.65%（group 3）, 0.70%（group 4） for the late phase（100 to 125 kg）, and based on the same digestible amino acid pattern by adding synthetic amino acids. The results showed that：Serum circulating lysine concentrations was higher with increasing DLys （P〈0.05）, but serum triglyeride, glucose concentrations were similar among groups（P〉0.05）. The concentrations of serum insulin（INS）, insulin growth factor-I （IGF-I）, luteinizing hormone（LH） and estradiol（E2） increased, then decreased with increasing DLys levels, and reached a maximum value in group 3（P〉0.05）, the concentration of serum INS in group 3 was significantly higher than those in group 1（P〈0.05）. Back fat thickness and ratio of estrus of gilts increased, then decreased with increasing DLys levels（P〉0.05）, the age of puberty of gilts in group 3 was significantly lower than those in group 4（P〈0.05）. The results indicated, based on ideal dietary amino acid pattern, the daily DLys intake were 17.82 and 17.29 g·d-1 for 70-100 kg and 100-125 kg （DLys level in the low-protein diets should be 0.71% and 0.65%）, respectively,which could increase the concentration of serum metabolites hormones INS, IGF-I, and elevate LH, E2 secretion. Meanwhile, reduced the age of puberty and improved the ratio of estrus in gilts.