Lactate uptake in the rumen and its contributions to subacute rumen acidosis of goats induced by high-grain diets

Abstract

Rumen acidosis is the consequence of feeding rapidly fermentable grain diets and it is considered the most common nutritional disorder in intensive feeding ruminants. Due to that mechanism of catabolism and transformation is driven by multi-factors, the role of ruminal lactate and its contribution to subacute rumen acidosis has not been well defined yet. The aim of this study is to evaluate the effects of SARA on the production, absorption, circulation, and transformation of lactate in the rumen. In this study, rumen samples were collected from 12 adult Saanen goats (44.5 ± 4.6 kg BW) equipped with permanent rumen cannula to measure rumen fermentation parameters, organic acids production, microbial profiles, and blood indicators to identify the occurrence of SARA. To further investigate the change in the disappearance rate of ruminal lactate, rumen fluid was collected and a batch culture was performed. The results showed that the clearance rate of ruminal lactate was accelerated by SARA, and the concentration of the ruminal lactate pool was stable. In addition, the rumen liquid dilution rate and the rumen liquid flow rate under the SARA condition of goats were lower than that in normal conditions. The ruminal lactate flow rate had no difference throughout the process of fermentation. However, in vitro data showed that the disappearance of lactate was reduced in SARA. By measuring the conversion of sodium L-[3-13C]-lactate in batch culture, it was found that the percentage of lactate converted to propionate was significantly lower in the SARA treatment and 16.13% more lactate converted to butyrate under SARA condition. However, the percentage of lactate transformed into acetate and butyrate was significantly increased in the SARA treatment than that of control. The relative population of total protozoa count in SARA was significantly reduced, while the relative population of Lactobacillus fermentum, Streptococcus bovis, Butyrivibrio fibrisolvens, Megasphaera elsdenii, and Selenomonas ruminantium in the SARA treatment was significantly induced (p < 0.05). It is concluded that the transformation of lactate into butyrate may promote the development of SARA. These findings provide some references to the diet formulation for preventing SARA.

Megasphaera elsdenii: Its Role in Ruminant Nutrition and Its Potential Industrial Application for Organic Acid Biosynthesis

“…However, McCann et al [ 46 ] observed no significant change in M. elsdenii RA upon SARA induction. He et al [ 47 ] reported a twofold increase in the relative abundance of M. elsdenii in non-lactating Saanen goats undergoing induction of SARA (elicited through high-concentrate feeding) compared with herdmates not subjected to SARA induction.…”

“…From a producer standpoint, the development of stable commercial products for frequent oral dosing to animals is essential for establishing the strain in the rumen in commercial herds under production conditions, or at least for maintaining a sufficient abundance between administrations of dosing, in order to achieve the goal of controlling acidosis. Finally, it is worth mentioning that any success of the probiotic M. elsdenii in controlling acute lactic acidosis may be compromised somewhat by the conversion of lactic acid to other VFAs (particularly butyric) with a resulting increased propensity to trigger SARA [ 47 ].…”

Nutrición animal: Texto de formación universitaria

“…La acidosis ruminal es un trastorno digestivo como consecuencia de la alimentación con dietas de granos rápidamente fermentables, considerada como el trastorno nutricional más común en tanto en el ganado de carne como en el de leche de alimentación intensiva (He et al, 2022). Hay dos variantes de acidosis ruminal, la acidosis ruminal aguda (ARA) y la acidosis ruminal subaguda (SARA).…”

“…En ambos casos el metabolito responsable es el ácido láctico o lactato, un producto intermediario en la fermentación microbial de los carbohidratos para su conversión en ácidos grasos volátiles, especialmente ácido propiónico. El lactato en el rumen es producido principalmente por la fermentación del almidón por Streptococcus bovis y catabolizado por lactato deshidrogenasa (LDH) de bacterias que utilizan lactato como Megasphaera elsdenii y Selenomonas ruminantium en el rumen (He et al, 2022).…”

A Chiral-LC-MS Method for the Simultaneous Quantification of Short-Chain Fatty Acids and D/L-Lactate in the Ruminal Fluid of Dairy Cows

“…Short-chain fatty acids (SCFA), also called volatile fatty acids (VFA) are the products of feed fermentation in the rumen [ 1 ], whereas D-/L-lactate are the intermediate products of starch fermentation in the rumen [ 2 ]. Given ruminal SCFA and lactate profiles are associated with ruminant feeding regime, ruminal microbial composition, as well as ruminal acidosis severity [ 1 ].…”