Department of Animal Science, Aarhus University, Foulum, Blichers Allé 20, P.O. Box 50, DK-8830 Tjele, Denmark.
Department of Animal Science, Aarhus University, Foulum, Blichers Allé 20, P.O. Box 50, DK-8830 Tjele, Denmark.
Animal. 2022 Jan;16(1):100439. doi: 10.1016/j.animal.2021.100439. Epub 2022 Jan 7.
Today, weaner diets are optimised using digestibility coefficients obtained from grower-finisher pigs, which may overestimate the digestibility in weaners. The aim of this study was to evaluate the standardised ileal digestibility (SID) of CP and amino acids (AAs), and the intestinal morphology in pigs 0-4 weeks postweaning when fed different protein sources. The experiment included 128 pigs weaned at day 28 and the protein sources were wheat, soybean meal (SBM), enzyme-treated soybean meal (ESBM), hydrothermally treated rapeseed meal (HRSM) and casein. The experiment was conducted as a difference method study including wheat in all diets. Eight pigs were slaughtered on the day of weaning (day 0) and six pigs/treatment were slaughtered at days 7, 14, 21, and 28 postweaning. The SID of CP and AA, as average over the four weeks, was lowest for ESBM and highest for wheat and casein, with SBM and HRSM being intermediate. The SID of CP and AA increased (both linear and quadratic, P < 0.05) over time after weaning. The average SID of CP for all protein sources postweaning was 0.38, 0.59, 0.76, and 0.71 on days 7, 14, 21, and 28, respectively. These differences were significant (P < 0.05) between days 7 and 21, and between days 7 and 28 (P < 0.05), whereas there tended to be a difference between days 7 and 14 (P = 0.06). Protein source did not affect the small intestinal morphology response parameters, whereas time after weaning did. Villous height and villous height to crypt depth ratio differed (P < 0.05) between the days 0 and 7, with shorter villi and a higher ratio at day 7. Crypt depth was not altered between days 0 and 7, or between days 7 and 14. For villi density, crypt density and small intestinal length, a significant increase from days 7 to 14 was observed, but there was no further increase to or difference between days 21 and 28. In conclusion, the low SID of CP in casein on day 7 (0.50) illustrates the challenges related to protein digestion in weanling pigs. The SID of CP and AA is very low during the first two weeks postweaning and time after weaning is more important for protein digestibility, than the source of protein. Fewer mature epithelial cells and less absorptive area in the small intestine in the early postweaning period may partly explain the poor protein digestibility.
今天，我们使用来自生长育肥猪的消化率系数来优化断奶仔猪日粮，这可能会高估断奶仔猪的消化率。本研究旨在评估不同蛋白质来源在断奶后 0-4 周龄仔猪的标准回肠可消化性（SID）、CP 和氨基酸（AA）以及肠道形态。该实验包括 128 头 28 日龄断奶的仔猪，蛋白质来源分别为小麦、豆粕（SBM）、酶处理豆粕（ESBM）、热处理菜粕（HRSM）和酪蛋白。该实验采用差异法进行，所有日粮中均包含小麦。8 头仔猪在断奶当天（第 0 天）屠宰，6 头/处理组在断奶后第 7、14、21 和 28 天屠宰。4 周内，ESBM 的 CP 和 AA 的 SID 最低，小麦和酪蛋白最高，SBM 和 HRSM 居中。CP 和 AA 的 SID 在断奶后随时间增加（线性和二次，P<0.05）。所有蛋白质来源的 CP SID 在断奶后第 7、14、21 和 28 天分别为 0.38、0.59、0.76 和 0.71，这些差异在第 7 天和第 21 天以及第 7 天和第 28 天之间均具有统计学意义（P<0.05），而在第 7 天和第 14 天之间有趋于显著的趋势（P=0.06）。蛋白质来源不影响小肠形态学反应参数，而断奶后时间有影响。绒毛高度和绒毛高度与隐窝深度的比值在第 0 天和第 7 天之间存在差异（P<0.05），第 7 天的绒毛较短，比值较高。隐窝深度在第 0 天和第 7 天之间或第 7 天和第 14 天之间没有变化。对于绒毛密度、隐窝密度和小肠长度，第 7 天到第 14 天之间观察到显著增加，但第 21 天到第 28 天之间没有进一步增加或差异。总之，第 7 天酪蛋白的低 CP SID（0.50）表明了断奶仔猪蛋白消化方面的挑战。CP 和 AA 的 SID 在断奶后前两周非常低，断奶后时间比蛋白质来源更重要。在早期断奶后时期，小肠中成熟的上皮细胞较少，吸收面积较小，这可能部分解释了蛋白质消化率较差的原因。
