Rumen papillae morphology of beef steers relative to gain and feed intake and the association of volatile fatty acids with kallikrein gene expression

Abstract

Feed costs are the most expensive input in beef production. Improvement in the ability of beef cattle to convert feed into meat would lower feed inputs and reduce the cost of production. The rumen epithelium is responsible for absorption and metabolism of nutrients and microbial by-products, and may play a significant role in gain or feed intake. Our objective was to determine the relationships among rumen papillae morphology, gene expression, volatile fatty acid concentrations, and gain and feed intake. Average daily gain (ADG) and average daily feed intake (ADFI) were collected on a crossbred population of beef steers over three feeding trials. Based on feed intake and weight gain differences, 48 steers were selected for the project (16 from each feeding study). At harvest, rumen epithelial samples were taken from three locations in the rumen of each animal. The number of papillae on 1 cm 2 of epithelium was counted to determine density. Papillae (n = 30) from each sample were measured for length and width. The density, length, and width were combined to determine surface enlargement factor (SEF). None of the morphological characteristics of the papillae (length, width, density or SEF) were associated with feed intake or gain (P > 0.10). Ruminal fluid was collected from steers (n = 15) in the third trial for volatile fatty acid (VFA) analysis to determine if a relationship between VFA and ADG or ADFI existed. No differences in volatile fatty acid (VFA) concentrations were associated (P > 0.17) with ADFI or ADG. VFA variation was also evaluated for a relationship with kallikrein (KLK) genes since ruminal butyrate concentrations have previously been associated with the transcript abundance KLK genes. Additionally, qRT-PCR data showed that variation in the transcript abundance of KLK6,8-10, and 13 associated with feed intake in our first trial of steers. Thus, we evaluated the transcript abundance of eight KLK genes in rumen 3 papillae from steers in the third trial (n = 16). Expression levels of KLK5 correlated with valerate concentrations in the rumen (P < 0.05), KLK10 correlated with acetate concentrations in the rumen (P < 0.05), KLK12 correlated with acetate and butyrate concentrations in the rumen (P < 0.05), and the expression levels of KLK9 and KLK10 were associated with gain. While rumen papillae morphology was not associated with beef steer gain or intake, our data suggests members of the kallikrein gene family have a relationship with the VFA environment in the rumen, and also appear to play a role in the highly correlated traits of ADG and ADFI.

Impact of weaning age on rumen development in artificially reared lambs1

“…When animals are in negative energy balance, elevated blood BHBA concentrations can result from BHBA production by the liver (Katz and Bergman, 1969), however, this is unlikely in the current study since plasma NEFA concentrations did not differ between EW and Ctrl lambs. Therefore, it is likely that the increased mean plasma BHBA concentrations of EW lambs reflects increased absorption of SCFA and ketogenic activity of the rumen epithelium after milk removal as observed previously in lambs and other ruminants (Steele et al, 2012;Deelen et al, 2016;Kern et al, 2016;Liu et al, 2016). These results indicate accelerated metabolic development of the rumen in EW compared to Ctrl lambs as an adaptation mechanism to enable absorption of SCFA from the rumen as milk is reduced as a component of the diet.…”

Postbiotic L. plantarum RG14 improves ruminal epithelium growth, immune status and upregulates the intestinal barrier function in post-weaning lambs

“…Lambs supplemented with postbiotics in the diet tended to have higher papillae length and width than control lambs. Rumen papillae involve three main physiological functions: (1) enlarge surface area for optimal nutrients absorption and microbial adherent to rumen wall, (2) allow products of digestion or metabolites to transfer from rumen to epithelial bed of the rumen and (3) protect the host through immune response 10,11 . The significant increase in rumen papillae may be attributed to the higher production of VFA in the rumen particularly butyric 12 .…”

“…The higher the length and width of the papillae on rumen wall indicate the morphological development of the epithelium. Improvement of papillae length and width will increase the surface area of papillae thus increase the capacity of absorption of nutrients and attachment of microbes to rumen wall 11 . Postbiotic supplementation in the diet did not affect villi height in all parts of the small intestine in both treated and control groups.…”

Rumen and liver measurements of lambs fed with high inclusions of crude glycerin in adaptation and finishing period of feedlot

“…The rumen epithelium has several physiological functions, such as the absorption and metabolism of nutrients and microbial by-products (volatile fatty acids). The rumen papillae increase the surface area for the absorption and microbial attachment to the rumen wall, playing a significant role in animals' feed intake and weight gain (Galfi et al, 1991;Kern et al, 2016). Although concentrate-rich diets may stimulate the development of ruminal papillae more than roughage-rich diets (Stobo et al, 1966), lesions in the papillae caused by acidosis may compromise the animal performance.…”