Alleviation effects of niacin supplementation on beef cattle subjected to heat stress: A metagenomic insight

Abstract

The objective of this study was to investigate the alleviation effects of niacin supplementation on beef cattle subjected to heat stress and to provide a theoretical basis for exploring the alleviation methods of heat stress environmental factors on the rumen of beef cattle. In the experiment, 36 Jinjiang bull cattle with a body weight of about 400 ± 20.0 kg were randomly divided into three treatments, each treatment contains four replicates, with three cattle in each replicate. Treatments included thermoneutral treatment (TN; temperature: 24–25°C, humidity: 45–55%), heat stress treatment, exposure to environmental temperature (HS; average THI: 82.74), and heat stress supplemented with niacin treatment (HN; high temperature + 800 mg/kg NA). Measured indicators were body temperature, respiratory rate, production performances, rumen fermentations, and microbial diversity. Results showed that adding niacin reduced the body temperature and respiratory rate (P < 0.05) but had no significant effect on the production performances compared with heat-stressed beef cattle. HS treatment significantly increased body temperature and respiratory rate (P < 0.01), while decreasing the content of acetic acid, butyric acid, and total volatile fatty acids (P < 0.05) compared with the TN treatment. Supplement of niacin did not affect ruminal fermentation parameters (P > 0.05) but had a decreased tendency on A/P (P < 0.1). Microbial diversity results showed that, at the phylum level, the relative abundance of Desulfobacterota in the HS treatment was increased compared with TN and HN treatment (P < 0.05). At the genus level, the relative abundance of Succiniclasticum and Family_XIII_AD3011 group in the HN treatment significantly proliferated compared with the HS treatment (P < 0.05). In conclusion, niacin supplementation may alleviate heat stress by proliferating those bacteria belonging to the phylum Succiniclasticum, which may further contribute to the digestion of cellulose and the improvement of the metabolic function of Jinjiang cattle under heat-stress conditions.

The effect of Phyllanthus emblica (Amla) fruit supplementation on the rumen microbiota and its correlation with rumen fermentation in dairy cows

“…Our result showed reduction of Desulfobacterota phylum when the dairy cows are supplemented with 200 and 400 g/d of FAF doses, indicating that these doses of FAF may create a healthier environment in the rumen and hindgut of the cows by minimizing the release of lipopolysaccharide (LPS) ( Huang et al, 2021 ). Additionally, supplementing FAF in the feed may also mitigate heat stress conditions in dairy cows ( Zou et al, 2022 ). However, further research is required to validate this potential benefit.…”

Dietary Supplementation with Bupleuri Radix Reduces Oxidative Stress Occurring during Growth by Regulating Rumen Microbes and Metabolites

“…Therefore, we speculated that BR could intervene to boost the proportional abundance of advantageous bacteria to intervene in rumen microbiota disturbance and preserve the health of SFWS. Research indicates that supplementing with niacin can potentially mitigate heat stress by elevating the relative abundance of Succiniclasticum [ 44 ]. According to the majority of research, OS and heat stress are tightly related [ 45 , 46 , 47 , 48 ].…”

Metagenomic sequencing identified microbial species in the rumen and cecum microbiome responsible for niacin treatment and related to intramuscular fat content in finishing cattle

“…In addition to being a coenzyme precursor, niacin has been known for its antilipolytic effect by activating the hydroxycarboxylic acid 2 receptor (HCA2), which effectively reduces the levels of all atherogenic lipoproteins including VLDL and LDL subclasses as well as Lp (a), and increases the levels of the protective lipoprotein of HDL ( Carlson, 2005 ; Pescara et al, 2010 ). Recent studies have demonstrated that the pharmacological dose of niacin did provide beneficial effects on animal health, particularly in high-yielding dairy cows under stress conditions ( Kristensen and Harmon, 2004 ; Pescara et al, 2010 ; Titgemeyer et al, 2011 ; Luo et al, 2017 , 2019 ; Zou et al, 2022 ), likely attributing to niacin’s positive influence on lipid metabolism or vasodilation ( Carlson, 2005 ; Pescara et al, 2010 ). Additionally, niacin plays important roles in converting ruminant volatile fatty acids (VFAs), such as acetate, into long-chain fatty acids ( Chilliard, 1993 ).…”

“…The complex microbial community effectively ensures rumen fermentation in ruminants, which primarily converts feedstuffs into essential nutrients, such as VFAs, ammoniate, vitamins, and microbial proteins ( Doreau and Ottou, 1996 ; Kristensen and Harmon, 2004 ; Zou et al, 2022 ). Niacin has been proven to promote rumen microbial growth, maintain rumen microecological homeostasis, and avoid lactate accumulation in the rumen wall ( Doreau and Ottou, 1996 ; Kristensen and Harmon, 2004 ; Luo et al, 2017 ).…”

“…Dietary niacin also inhibited starch utilization and stimulated fiber degradation primarily by reducing the relative abundance of Proteobacteria , Succiniclasticum , Acetivibrio , and Treponema , or increasing the abundance of Prevotella ( Kristensen and Harmon, 2004 ). A recent study has demonstrated that niacin supplementation might alleviate heat stress by promoting the proliferation of bacteria belonging to phylum Succiniclasticum , which in turn contributed to the cellulose digestion and metabolic function improvement of beef cattle under heat-stress conditions ( Zou et al, 2022 ). Dietary niacin should also enhance the number and density of rumen protozoa ( Doreau and Ottou, 1996 ).…”