Lawal Abiola S, Fu Yuechi, Ogunribido Tobi Z, Brackett Madison N, Adeola Olayiwola, Ajuwon Kolapo M
Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA.
J Anim Sci. 2025 Jan 4;103. doi: 10.1093/jas/skaf200.
A total of 160 pigs (initial body weight [BW], 5.79 ± 0.01 kg) were used to investigate the effects of dietary nucleotides and branched-chain amino acids (BCAA) supplementation of low-protein diets on growth performance, blood metabolites, short-chain fatty acids (SCFA), apparent ileal and total tract digestibility of nutrients (AID and ATTD). Following a 3-d adaptation period on a common diet after weaning, pigs were randomly assigned to 1 of the 5 dietary treatments using a randomized complete block design. Each treatment consisted of 8 replicate pens with 4 pigs per pen. The experimental diets included a normal-crude protein (CP) Positive Control (PC) diet with CP at 22%, 20.6%, and 19.4% for phases 1, 2, and 3, respectively; a BCAA-deficient low-CP Negative Control (NC) diet with CP at 16%, 14.6%, 13.4% for phases 1, 2, and 3, respectively; NC diet supplemented with crystalline isoleucine and valine (NC + BCAA); NC diet supplemented with 9 g/kg of dietary nucleotides (NC + NL9); and NC diet supplemented with both BCAA and nucleotides (NC + BCAA + NL9). Average daily feed intake, average daily gain (ADG), and gain-feed ratio (G:F) were recorded. Fecal samples were collected on days 39, 40, and 41 to determine the ATTD of nutrients. Blood samples were collected on day 42 to measure blood metabolites and pigs were euthanized to determine the AID of nutrients and colonic SCFA. Pigs fed the PC diet had the highest (P < 0.0001) overall ADG, G:F, and final BW, with intermediate values in NC + BCAA + NL9 and NC + BCAA, and the lowest values in NC + NL9 and NC. Blood urea nitrogen concentrations decreased (P < 0.0001) with reduced CP, while serum glucose, insulin, and glutathione concentrations remained unaffected. The NC diet had the lowest (P < 0.0001) serum insulin-like growth factor-1 concentration (IGF-1), with partial recovery in the NC + BCAA diet and complete recovery in the NC + BCAA + NL9 diet, compared to PC. The NC + BCAA + NL9 diet tended to increase (P = 0.09) serum uric acid concentration and had the highest ATTD of nitrogen (N), gross energy, and dry matter (P < 0.05) as well as the highest AID of N and phosphorus (P < 0.0001 and P < 0.001, respectively). Additionally, the NC diet showed a tendency to decrease (P = 0.08) the total colonic SCFA concentration. Results suggest that nucleotide supplementation, following BCAA addition to low-CP diets, conferred additional beneficial effects on growth performance and nutrient digestibility in pigs.
总共160头猪（初始体重[BW]为5.79±0.01千克）用于研究在低蛋白日粮中添加日粮核苷酸和支链氨基酸（BCAA）对生长性能、血液代谢物、短链脂肪酸（SCFA）、养分的回肠表观消化率和全肠道消化率（AID和ATTD）的影响。断奶后在普通日粮上经过3天的适应期后，采用随机完全区组设计将猪随机分配到5种日粮处理中的1种。每个处理包括8个重复栏，每栏4头猪。实验日粮包括正常粗蛋白（CP）阳性对照（PC）日粮，第1、2和3阶段的CP分别为22%、20.6%和19.4%；BCAA缺乏的低CP阴性对照（NC）日粮，第1、2和3阶段的CP分别为16%、14.6%和13.4%；添加结晶异亮氨酸和缬氨酸的NC日粮（NC + BCAA）；添加9克/千克日粮核苷酸的NC日粮（NC + NL9）；以及同时添加BCAA和核苷酸的NC日粮（NC + BCAA + NL9）。记录平均日采食量、平均日增重（ADG）和增重耗料比（G:F）。在第39、40和41天收集粪便样本以测定养分的ATTD。在第42天采集血液样本以测量血液代谢物，然后对猪实施安乐死以测定养分的AID和结肠SCFA。采食PC日粮的猪总体ADG、G:F和末重最高（P < 0.0001），NC + BCAA + NL9和NC + BCAA组的值居中，NC + NL9和NC组的值最低。随着CP降低，血尿素氮浓度降低（P < 0.0001），而血清葡萄糖、胰岛素和谷胱甘肽浓度不受影响。与PC相比，NC日粮的血清胰岛素样生长因子-1浓度（IGF-1）最低（P < 0.0001），在NC + BCAA日粮中部分恢复，在NC + BCAA + NL9日粮中完全恢复。NC + BCAA + NL9日粮倾向于提高（P = 0.09）血清尿酸浓度，并且氮（N）、总能和干物质的ATTD最高（P < 0.05），N和磷的AID也最高（分别为P < 0.0001和P < 0.001）。此外，NC日粮有降低总结肠SCFA浓度的趋势（P = 0.08）。结果表明，在低蛋白日粮中添加BCAA后再添加核苷酸，对猪的生长性能和养分消化率有额外的有益影响。
