Regulation of pancreatic exocrine in ruminants and the related mechanism: The signal transduction and more

Abstract

The unique structure of the stomach, including the rumen, reticulum, omasum, and abomasum, indicates the differences between the ruminant and monogastric animals in the digestion of nutrients. This difference is reflected in the majority of dietary nutrients that may be fermented in the rumen. Significant proteins and a certain amount of starch can flow to the small intestine apart from rumen. The initial phase of small intestinal digestion requires pancreatic digestive enzymes. In theory, the enzymatic digestion and utilization efficiency of starch in the small intestine are considerably higher than that in the rumen, but the starch digestibility in the small intestine is quite low in ruminants. Therefore, improving the digestion of nutrients, especially starch in the small intestine is more urgent for high-yield ruminants. Although the pancreas plays a central role in nutrient digestion, the progress of research investigating pancreatic exocrine regulation in the ruminant is slow due to some factors, such as the complex structure of the pancreas, the selection of experimental model and duration, and internal (hormones or ages) and external (diet) influences. The present review is based on the research findings of pancreatic exocrine regulation of dairy animals and expounded from the physiological structure of the ruminant pancreas, the factors affecting the digestion and exocrine processing of carbohydrates, and the regulatory mechanism governing this process. The review aims to better understand the characteristics of enzymatic digestion, thereby advancing pancreatic exocrine research and improving the digestion and utilization of nutrients in ruminants. Additionally, this review provides the theoretical basis for improving nutrient utilization efficiency, reducing wastage of feed resources, and promoting the efficient development of the dairy industry.

Exploring the Role of G Protein Expression in Sodium Butyrate-Enhanced Pancreas Development of Dairy Calves: A Proteomic Perspective

“…In our attempt to investigate the mechanism by which milk-supplemented SB influences pancreas development, we examined the potential impact on exocrine (CCK and secretin) and endocrine (GLP-1, GIP, and PACAP) hormones. , However, the results obtained in this study were only a first step. Further research is warranted to comprehend how butyrate derived from the intestines specifically affects pancreatic development, particularly in terms of extracellular mechanisms involved in exocrine and endocrine processes.…”

“…14 Additionally, the regulation of pancreatic exocrine function involves mechanisms such as intracellular calcium signaling, proteasome activity, and molecular signaling pathways. 4 pancreatic organizational structure in relation to SB supplementation and its influence on early age calf pancreatic exocrine development.…”

“…More recent research has highlighted the positive impact of butyrate and its derivatives, found in pasteurized milk or waste milk, on promoting development of the small intestine, health, and growth in dairy calves. , Traditional investigative approaches, like evaluating the morphological features of the pancreas and detailed ultrastructural analysis of pancreatic acinar cells (utilizing technologies such as transmission electron microscopy to visualize zymogen granules), have been pivotal in shedding light on the development of the exocrine function of the pancreas in dairy calves . Additionally, the regulation of pancreatic exocrine function involves mechanisms such as intracellular calcium signaling, proteasome activity, and molecular signaling pathways . However, there remains a paucity of research exploring the specific mechanisms (by which SB enhances pancreatic exocrine hormone secretion) and a comprehensive evaluation of the pancreatic organizational structure in relation to SB supplementation and its influence on early age calf pancreatic exocrine development.…”

“…Hormones such as secretin and cholecystokinin are known to upregulate these exocrine functions. 4 The endocrine component, primarily the islets of Langerhans, harbors various cell types with alpha cells secreting glucagon, beta cells producing insulin, and other cells contributing somatostatin and pancreatic polypeptide. 5,6 Moreover, hormones like glucagon-like peptide 1, gastric inhibitory polypeptide, and pituitary adenylate cyclaseactivating polypeptide positively influence pancreatic endocrine secretory activities.…”

Nutritional and Physiological Constraints Contributing to Limitations in Small Intestinal Starch Digestion and Glucose Absorption in Ruminants

“…The effects of nutrition on pancreatic exocrine function in ruminants have been reviewed previously [16,54,[82][83][84][85][86][87]. In nonruminants, carbohydrase activities typically increase proportional to luminal substrate flow [88].…”