ISSUE FOCUS FEED & ADDITIVE MAGAZINE October 2024 49 trations (Waldron et al., 2003). Elevated plasma LPS concentrations are associated with a decrease in blood calcium and magnesium due to an increase in IL-1β (Gray et al., 2007), which may contribute to milk fever. LPS can also impact lipid metabolism. Research by Chirivi et al. (2022) demonstrated that LPS can reduce the antilipolytic effects of insulin, leading to dysregulation of lipolysis. This is particularly important for transition cows that require effective regulation of fat release and storage due to general negative energy balance and potential declines in liver function. HOW CAN THE LPS THREAT BE REDUCED? The lipopolysaccharide content of the gut increases during acidosis and managing diets to reduce clinical and subclinical acidosis is beneficial. Increasing fibre content and reducing easily fermentable carbohydrates can reduce the likelihood of excess short-chain fatty acids or, in the case of clinical acidosis, lactic acid. However, energy requirements to maximise milk or muscle production may limit the extent to which diet manipulation can be employed. Including buffers and certain yeast products can help mitigate acidosis and increase rumen pH. Yeast can compete for soluble carbohydrates that could otherwise be used by Streptococcus bovis and Lactobacillus to produce lactic acid; additionally, yeast may encourage the growth of Megasphaera eldenii, which can convert lactic acid into butyric acid (Amin and Mao, 2021). Feed additives can also be used to reduce the growth of Gram-negative (-) bacteria, such as E. coli and Salmonella species. Yeast cell wall products have demonstrated an ability to bind live bacteria, thereby reducing their ability to grow and reproduce. Feeding fructo-oligosaccharides supports the growth of probiotic or beneficial bacteria, which can reduce pathogenic bacterial growth by controlling the micro-environment around the microvilli through competitive inhibition. The growth of Gram-negative bacteria and subsequent LPS production can never be entirely eliminated. However, the effects of LPS can be mitigated through feed ingredients that help maintain healthy homeostasis, support the growth of probiotic bacteria, and promote intestinal integrity, thereby limiting the growth and prevalence of harmful bacteria. Additionally, specific inorganic compounds (such as aluminosilicates) and organic compounds (such as components of yeast cell walls) can bind LPS, preventing both their absorption and their ability to stimulate inflammation. Although LPS presents a genuine threat to animal production, their effects can be mitigated using specific feed additives and practical management strategies to reduce the associated risks. References are available upon request. About Bryan Miller Bryan Miller has been in the feed industry for over 35 years in feed mill management, product development (including authoring patents) and technical services. For most of the past 10 years he has focused on gut and liver health, including mycotoxin remediation. Animal Nutrition SPECIALISTS IN MYCOTOXIN REMEDIATION, PROBIOTICS AND PHYTOGENIC SOLUTIONS For more information visit volac.com or contact feedadditives@volac.com
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