Histomorphometric Adaptation of Yak (Bos grunniens) Abomasum to the Qinghai-Tibetan Plateau Environment

Abstract

SUMMARY: Six abomasums of yaks (Bos grunniens) were studied with gross dissection and histological methods. It was found that the mucosa of the yak abomasum was covered with simple columnar epithelium. There were lots of spiral folds (≥10) in the fundic glandular area. The developed membrane of lamina propria was occupied by high density glands. According to the morphological characteristics of the glands, the abomasum was divided into the cardiac, gastric and pyloric glands. Cardiac glands were curved tubular glands with the intumescent bottom and small glandular cavity. Fundic glands were simple tubular glands or branched tubular glands, where the chief, parietal and mucous neck cells can be observed clearly. Pyloric glands were curled tubular glands, the closer to the deep of the lamina propria, the more obvious the glands curl. Staining of glycoconjugate revealed that the mucosal epithelium of the cardiac gastric and pyloric glands and gastric pits epithelium mainly secreted neutral glycoconjugate, but other portions of cardiac and gastric glands secreted mixed and acid glycoconjugate respectively. By Gordon-Sweet's reticular fiber staining, it was found that the mucous neck cells possessed the characteristic of argyrophilic phenomenon. There was a large number of argyrophilic granules in the supranuclear cytoplasm in contrast with the chief cells. Furthermore, there were isolated lymphoid nodules and diffuse lymphoid tissue in the abomasum glands, especially in corpus abomasi. Grimelius silver staining showed that the argyrophil cells were located in the glandular epithelium and lamina propria of glands, which can also be observed in connective tissue. These endocrine cells dispersed individually in epithelial cells, occasionally in 3-5 cell groups. Therefore, the yaks were grazed throughout the year on diverse natural grassland and had evolved morphological characteristics of the abomasum enabling them to consume a wide variety of plant species, thereby better adapting them to harsh plateau environment.

Morphologic Effects of Filiform Papilla Root on the Lingual Mechanical Functions of Chinese Yellow Cattle

“…Various studies with light and scanning electron microscopy have been conducted on the histological and morphological features of filiform papillae in bovines, such as cows (Steflik et al, 1983;Chamorro et al;de Paz Cabello et al), buffaloes (Scala et al, 1993), Japanese Black cattle (Sato et al, 1994), Zavot cattle (Sari et al, 2010), yaks Wang et al, 2015), and domestic cattle (Scala et al, 1995). Extensive morphologic research has also been presented on the filiform papillae in other ruminant species and breeds, including Formosan serows (Atoji et al, 1998), Blackbucks (Emura et al, 1999), Barbary sheep (Emura et al, 2000), Saanen goats (Kurtul & Atalgın, 2008), goitered gazelles (Harem et al, 2011), chital deer (Erdogan & Pérez, 2014), giraffes (Emura et al, 2013), one-humped camels (El Sharaby et al, 2012), and Bactrian camels (Eerdunchaolu et al, 2001).…”

The uniqueness and superiority of energy utilization in yaks compared with cattle in the highlands: A review

“…Yaks have evolved notably different gut function to other ruminants, possessing a greater density of ruminal papillae in the rumen epithelium and more pleats in the mucosa surface of their abomasum compared with cattle ( Beiranvand et al., 2014 ; Wang et al., 2015 ), which increases the surface area of the gastrointestinal tract and improves absorptive capacity. Unlike cattle, the orifices between the reticulum and omasum in yaks can shrink to decrease the passage rate of less nutritious forages during the cold season, leading to prolonged and sufficient digestion of this feed under poor forage conditions ( Ghoshal and Bal, 1989 ).…”

Effect of high proportion concentrate dietary on Yak jejunal structure, physiological function and protein composition during cold season

“…However, long-term feeding of a highly concentrated diet can eventually have severe impacts on animal health, leading to metabolic dysfunction related to rumen microorganisms, such as accumulation of volatile fatty acids (VFAs) and decreases in pH. Fermentable carbohydrates enter the small intestine through the rumen, causing intestinal acidosis, changes in the microbial community structure and destruction of intestinal epithelial morphology and structure 5 .…”