Mazinani Mitra, Contreras-Correa Zully E, Behzadan Vahid, Gopal Shreya, Lemley Caleb O
Department of Animal and Dairy Sciences, University of Idaho, Moscow, ID 83844, USA.
Department of Animal and Dairy Sciences, Mississippi State University, Starkville, MS 39762, USA.
Animals (Basel). 2022 Jul 16;12(14):1818. doi: 10.3390/ani12141818.
The objective of the current study was to examine the effects of maternal feed restriction and melatonin supplementation on fetal cardiomyocyte cell development parameters and predict binucleation and hypertrophy using machine learning techniques using pregnant beef heifers. Brangus heifers (n = 29) were assigned to one of four treatment groups in a 2 × 2 factorial design at day 160 of gestation: (1) 100% of nutrient requirements (adequately fed; ADQ) with no dietary melatonin (CON); (2) 100% of nutrient requirements (ADQ) with 20 mg/d of dietary melatonin (MEL); (3) 60% of nutrient requirements (nutrient-restricted; RES) with no dietary melatonin (CON); (4) 60% of nutrient requirements (RES) with 20 mg/d of dietary melatonin (MEL). On day 240 of gestation, fetuses were removed, and fetal heart weight and thickness were determined. The large blood vessel perimeter was increased in fetuses from RES compared with ADQ ( = 0.05). The total number of capillaries per tissue area exhibited a nutrition by treatment interaction ( = 0.01) where RES-MEL increased capillary number compared ( = 0.03) with ADQ-MEL. The binucleated cell number per tissue area showed a nutrition by treatment interaction ( = 0.010), where it was decreased in RES-CON vs. ADQ-CON fetuses. Hypertrophy was estimated by dividing ventricle thickness by heart weight. Based on machine learning results, for the binucleation and hypertrophy target variables, the Bagging model with 5 Decision Tree estimators and 3 Decision Tree estimators produced the best results without overfitting. In the prediction of binucleation, left heart ventricular thickness feature had the highest Gin importance weight followed by fetal body weight. In the case of hypertrophy, heart weight was the most important feature. This study provides evidence that restricted maternal nutrition leads to a reduction in the number of cardiomyocytes while melatonin treatment can mitigate some of these disturbances.
本研究的目的是使用怀孕的肉用小母牛，通过机器学习技术研究母体饲料限制和补充褪黑素对胎儿心肌细胞发育参数的影响，并预测双核化和肥大情况。在妊娠第160天，将布安格斯小母牛（n = 29）按照2×2析因设计分配到四个处理组之一：（1）满足100%营养需求（饲喂充足；ADQ）且不添加日粮褪黑素（对照组；CON）；（2）满足100%营养需求（ADQ）且添加20 mg/d日粮褪黑素（MEL）；（3）满足60%营养需求（营养限制；RES）且不添加日粮褪黑素（CON）；（4）满足60%营养需求（RES）且添加20 mg/d日粮褪黑素（MEL）。在妊娠第240天，取出胎儿，测定胎儿心脏重量和厚度。与ADQ组相比，RES组胎儿的大血管周长增加（P = 0.05）。每组织面积的毛细血管总数表现出营养与处理的交互作用（P = 0.01），其中RES-MEL组的毛细血管数量比ADQ-MEL组增加（P = 0.03）。每组织面积的双核细胞数量表现出营养与处理的交互作用（P = 0.010），RES-CON组胎儿比ADQ-CON组胎儿减少。通过将心室厚度除以心脏重量来估计肥大情况。基于机器学习结果，对于双核化和肥大目标变量，具有5个决策树估计器和3个决策树估计器的Bagging模型产生了最佳结果且无过拟合现象。在双核化预测中，左心室厚度特征的基尼重要性权重最高，其次是胎儿体重。在肥大情况中，心脏重量是最重要的特征。本研究提供了证据，表明母体营养受限会导致心肌细胞数量减少，而褪黑素处理可减轻其中一些干扰。
