The objectives of this study were to assess the effect of using heat-treated canola meal (CM) and glycerol inclusion in starter mixtures on starter intake, growth, and gastrointestinal tract development in Holstein bull calves. In the first study, a protocol for the heat treatment of CM was evaluated by comparing commercial CM that was exposed to 0, 100, 110, or 120°C of heat treatment for 10 min. Following heat treatment, in situ crude protein (CP) ruminal degradability and estimated intestinal CP digestibility were assessed. It was observed that the degradable fractions of dry matter and CP in CM decreased linearly with increasing temperature of heat treatment. The estimated intestinal CP digestibility was greatest when CM was heated to 110°C. In the second study, 28 bull calves were used in a randomized complete block design. Calves were fed pelleted starters containing CM or CM that was heat-treated to 110°C for 10 min. Diets also contained 0 or 5% glycerol on a dry matter basis. The study lasted 51 d, ending on the first day of weaning. Starter intake, average daily gain (ADG), ruminal short-chain fatty acid concentrations, morphology of the rumen and small intestine, gene expression (MCT1, GPR41, GPR43, UTB, AQP3, PEPT1, PEPT2, ATB0+, and EAAC1) in the ruminal, jejunal, and ileal epithelium, and brush border enzyme activities in the duodenum, jejunum, and ileum were investigated. Few interactions between heat-treated CM and glycerol inclusion were observed. Feeding heat-treated CM did not affect starter intake. However, feeding heat-treated CM to calves tended to reduce ADG and decreased the weight of ruminal and jejunal tissue. Heat treatment did not affect gene expression or brush border enzyme activities in the small intestine. Glycerol inclusion tended to increase cumulative starter intake and increased cumulative body weight gain. Use of glycerol reduced ruminal pH and increased the concentration of ruminal short-chain fatty acids. Additionally, glycerol inclusion increased abomasal, duodenal, jejunal, and cecal digesta weights and tended to increase the weight of the jejunal tissue. Glycerol supplementation tended to downregulate the expression of MCT1 in the ruminal epithelium, and upregulated the expression of MCT1 in the epithelium of proximal jejunum. In conclusion, heat treatment of CM may negatively affect calf growth and gastrointestinal tract development. Glycerol inclusion may increase starter intake, ADG, ruminal fermentation, and intestinal development in calves when CM is used as a main source of protein in pelleted starter mixture.

这项研究的目的是评估在霍尔斯坦公牛犊中使用热处理的低芥酸菜籽粉（CM）和甘油混合在发酵剂混合物中对发酵剂摄入，生长和胃肠道发育的影响。在第一个研究中，通过比较暴露于0、100、110或120°C热处理10分钟的商业CM，评估了CM的热处理方案。热处理后，评估了原位粗蛋白（CP）的瘤胃降解性和估计的肠CP消化率。观察到，随着热处理温度的升高，CM中干物质和CP的可降解分数线性降低。当CM加热到110°C时，估计的肠CP消化率最大。在第二项研究中，将28只公牛犊用于随机完整块设计。给小牛喂食含CM的颗粒状起子或将CM热处理至110°C 10分钟。饮食中以干物质计还含有0或5％的甘油。研究持续了51天，直到断奶的第一天结束。入门摄入量，平均日增重（ADG），瘤胃短链脂肪酸浓度，瘤胃和小肠的形态，基因表达（MCT1，GPR41，GPR43，UTB，AQP3，PEPT1，PEPT2，ATB0 +和EAAC1）在瘤胃，空肠和回肠上皮中，并研究了十二指肠，空肠和回肠的刷状边界酶活性。观察到热处理的CM和甘油夹杂物之间几乎没有相互作用。喂食经过热处理的CM不会影响起动机的摄入量。但是，将经过热处理的CM喂给犊牛往往会降低ADG并降低瘤胃和空肠组织的重量。热处理不影响小肠中的基因表达或刷状边界酶活性。甘油的掺入倾向于增加累积的起始剂摄入和增加的累积体重增加。使用甘油可降低瘤胃pH值，并提高瘤胃短链脂肪酸的浓度。此外，甘油的包涵增加了腹部，十二指肠，空肠，和盲肠消化物的重量，并倾向于增加空肠组织的重量。甘油的补充倾向于下调胆囊癌的表达。MCT1在瘤胃上皮中，并上调MCT1在空肠近端上皮中的表达。总之，CM的热处理可能会对小腿的生长和胃肠道的发育产生负面影响。当CM用作颗粒状起子混合物中蛋白质的主要来源时，甘油的混入可能增加小腿的起子摄入，ADG，瘤胃发酵和肠道发育。