Department of Animal Sciences, North Dakota State University, Fargo, ND 58108, USA.
Department of Animal Sciences, North Dakota State University, Fargo, ND 58108, USA.
Domest Anim Endocrinol. 2021 Jan;74:106555. doi: 10.1016/j.domaniend.2020.106555. Epub 2020 Aug 21.
The objective of this experiment was to evaluate the effects of nutrient restriction and melatonin supplementation during mid-to-late gestation on maternal and fetal small intestinal carbohydrase activities in sheep. Ewes were randomly assigned to one of 4 dietary treatments arranged in a 2 × 2 factorial design. Ewes were fed to provide 100% (adequate; ADQ) or 60% (restricted; RES) of nutrient recommendations, and diets were supplemented with either no melatonin (control; CON) or 5 mg melatonin/d (melatonin; MEL). This resulted in 4 treatment groups: CON-ADQ (n = 7), CON-RES (n = 8), MEL-ADQ (n = 8), MEL-RES (n = 8). Treatments began on day 50 of gestation, and ewes were euthanized on day 130 for tissue collection. The maternal and fetal small intestine were collected and assayed for small intestinal carbohydrase activities. Data were analyzed using the GLM procedure of SAS with fetal sex, melatonin, nutrition, and the melatonin by nutrition interaction included in the model statement. There were no melatonin by nutrition interactions for maternal or fetal small intestinal protein concentration or carbohydrase activities (P ≥ 0.11). Dietary melatonin supplementation decreased (P = 0.03) maternal small intestinal protein concentration by 22.7% and increased (P = 0.03) maternal small intestinal glucoamylase, isomaltase, and maltase activity per gram protein by 45.5%, 41.3%, and 40.6%, respectively. Nutrient restriction from mid-to-late gestation did not influence (P ≥ 0.46) maternal small intestinal protein concentration, or maltase, isomaltase, and lactase activity. Maternal glucoamylase activity per gram intestine increased (P = 0.05) with nutrient restriction by 49.1%. Melatonin supplementation and maternal nutrient restriction did not influence (P ≥ 0.15) fetal small intestinal protein concentration, or glucoamylase, isomaltase, and lactase activity. Maternal nutrient restriction from mid-to-late gestation decreased (P = 0.05) fetal maltase activity per gram intestine by 20.5% but did not influence fetal maltase activity per gram protein. These data indicate that some maternal and fetal carbohydrases are influenced by nutrient restriction and melatonin supplementation in sheep. More information is needed to understand how nutritional and hormonal factors regulate digestive enzyme activity in ruminants to design improved maternal nutrition programs to optimize fetal growth and development while maintaining maternal productivity.
本实验旨在评估妊娠中期至晚期营养限制和褪黑素补充对绵羊母体和胎儿小肠碳水化合物酶活性的影响。将母羊随机分配到 4 种饮食处理组中，采用 2×2 析因设计。母羊的饲养量为提供 100%（充足；ADQ）或 60%（限制；RES）的营养推荐量，并且饮食分别补充无褪黑素（对照；CON）或 5mg/d 褪黑素（褪黑素；MEL）。这导致了 4 个处理组：CON-ADQ（n=7）、CON-RES（n=8）、MEL-ADQ（n=8）、MEL-RES（n=8）。处理从妊娠第 50 天开始，在妊娠第 130 天处死母羊以收集组织。收集母体和胎儿小肠并测定小肠碳水化合物酶活性。使用 SAS 的 GLM 程序分析数据，模型语句中包含胎儿性别、褪黑素、营养和褪黑素与营养的相互作用。母体和胎儿小肠的蛋白质浓度或碳水化合物酶活性没有褪黑素与营养的相互作用（P≥0.11）。日粮褪黑素补充降低了（P=0.03）母体小肠蛋白质浓度 22.7%，并分别增加了（P=0.03）母体小肠的葡萄糖淀粉酶、异麦芽糖酶和麦芽糖酶活性每克蛋白质 45.5%、41.3%和 40.6%。妊娠中期至晚期的营养限制并没有影响（P≥0.46）母体小肠蛋白质浓度，或麦芽糖酶、异麦芽糖酶和乳糖酶活性。每克肠道的母体葡萄糖淀粉酶活性随着营养限制而增加（P=0.05），增加了 49.1%。褪黑素补充和母体营养限制没有影响（P≥0.15）胎儿小肠的蛋白质浓度，或葡萄糖淀粉酶、异麦芽糖酶和乳糖酶活性。妊娠中期至晚期母体营养限制降低了（P=0.05）胎儿每克肠麦芽糖酶活性 20.5%，但没有影响胎儿每克蛋白质的麦芽糖酶活性。这些数据表明，在绵羊中，一些母体和胎儿的碳水化合物酶受到营养限制和褪黑素补充的影响。需要更多的信息来了解营养和激素因素如何调节反刍动物的消化酶活性，以设计改进的母体营养计划，从而在保持母体生产力的同时优化胎儿的生长和发育。
