Feedlot diets containing different starch levels and additives change the cecal proteome involved in cattle’s energy metabolism and inflammatory response

Abstract

Diets for feedlot cattle must be a higher energy density, entailing high fermentable carbohydrate content. Feed additives are needed to reduce possible metabolic disorders. This study aimed to analyze the post-rumen effects of different levels of starch (25%, 35%, and 45%) and additives (monensin or a blend of essential oils and exogenous α-amylase) in diets for Nellore feedlot cattle. The cecum tissue proteome was analyzed via two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and then differentially expressed protein spots were identified with liquid chromatography–tandem mass spectrometry (LC–MS/MS). The use of blends of essential oils associated with α-amylase as a feed additive promoted the upregulation of enzymes such as triosephosphate isomerase, phosphoglycerate mutase, alpha-enolase, beta-enolase, fructose-bisphosphate aldolase, pyruvate kinase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), l-lactate dehydrogenase B, l-lactate dehydrogenase A chain, l-lactate dehydrogenase, and ATP synthase subunit beta, which promote the degradation of carbohydrates in the glycolysis and gluconeogenesis pathways and oxidative phosphorylation, support pyruvate metabolism through the synthesis of lactate from pyruvate, and participate in the electron transport chain, producing ATP from ADP in the presence of a proton gradient across the membrane. The absence of proteins related to inflammation processes (leukocyte elastase inhibitors) in the cecum tissues of animals fed essential oils and amylase may be because feed enzymes can remain active in the intestine and aid in the digestion of nutrients that escape rumen fermentation; conversely, the effect of monensin is more evident in the rumen and less than 10% results in post-ruminal action, corroborating the hypothesis that ionophore antibiotics have a limited effect on the microbiota and intestinal fermentation of ruminants. However, the increase in starch in these diets promoted a downregulation of enzymes linked to carbohydrate degradation, probably caused by damage to the cecum epithelium due to increased responses linked to inflammatory injuries.

Physiological, Nutritional and Transcriptomic Responses of Sturgeon (Acipenser schrenckii) to Complete Substitution of Fishmeal with Cottonseed Protein Concentrate in Aquafeed

“…Conversely, the increase in mPEPCK and G6Pase enzymes suggests an increase in carbohydrate synthesis and excretion, which could be a way for the fish to maintain glucose homeostasis as plant protein may not be as efficient at supplying energy as fishmeal [ 8 , 77 ]. The increases in FBPase and ENO1 may also suggest an increase in the synthesis of fructose-6-phosphate and pyruvate, which could provide more energy to fish [ 78 ]. The increased expression of ENO1, an enzyme involved in fermentation, observed in fish fed with plant protein-based diets may suggest that fermentation is more extensively used as a means of energy production due to the lower energy efficiency of plant protein compared to fishmeal [ 79 ].…”

Feedlot performance, rumen and cecum morphometrics of Nellore cattle fed increasing levels of diet starch containing a blend of essential oils and amylase or monensin

“…Thus, acidification of the intestinal environment may lead to an increase in lesions in the cecal epithelium and a decrease in the number of goblet cells and enterocytes because the intestinal epithelium is more sensitive to pH changes than the rumen ( 64 ). However, in a companion study, Rocha et al ( 65 ) reported that cattle fed BEO plus amylase surprisingly did not have proteins related to inflammatory processes (leukocyte elastase inhibitors) in the cecal tissues, although cecal lesions increased in response to BEO. This could be because feed enzymes remain active in the intestine and can help digest nutrients that escape rumen fermentation, or they may have even had an anti-inflammatory effect, but they cannot control cecal lesions.…”

“…The intestinal epithelium was mechanically stimulated to secrete mucus, which they attributed to the effect of SCFAs on mucus thickening ( 69 ). The use of high-starch diets for cattle can lead to lesions and an inflammatory response in the cecum ( 65 ). Studies evaluating cecal morphometric parameters, cecal epithelial health, and the correlation of these parameters with animal performance are limited in the literature ( 44 , 70 ).…”

“…On the other hand, the higher DMI could have caused a higher production of SCFA, which would develop the cecum and make it less susceptible to inflammatory processes ( 33 , 44 ). The increase in dietary starch content may promote the down-regulation of enzymes related to carbohydrate degradation, likely caused by damage to the cecal epithelium due to increased responses associated with inflammatory injury ( 65 ).…”

“…On the other hand, animals receiving MON had the lowest levels of fecal starch, which may be related to the effectiveness of this additive in influencing rumen fermentation, selection, and stimulating the growth of rumen bacteria, thereby preventing starch losses via feces. Ionophore antibiotics have limited effects on the microbiota and intestinal fermentation of ruminants, as the effect of monensin is more likely to be observed in the rumen ( 65 ). There are reports that BEO can affect the colonization of starch-rich substrates by rumen bacteria, thereby increasing the availability and utilization of starch in the rumen ( 75 ).…”