Effects of ensiling sugarcane tops with bacteria-enzyme inoculants on growth performance, nutrient digestibility, and the associated rumen microbiome in beef cattle

Abstract

Major challenges when ensiling sugarcane tops include fermentation that results in high quantities of alcohol and decrease a of nutrient digestibility due to the accumulation of fiber components. Increased efforts to apply bacteria-enzyme inoculants in silage have the potential to improve nutrient digestibility. This study aimed to evaluate the effects of ensiling sugarcane tops with bacteria-enzyme inoculants or mixed bacterial inoculants on growth performance, nutrient digestibility, and rumen microbiome in beef cattle. Chopped sugarcane tops were ensiled in plastic bags for 60 days after application of 1) no inoculant (CK); 2) bacteria-enzyme inoculants containing Pediococcus acidilactici, Saccharomyces cerevisiae, cellulase, and xylanase (T1, viable colony-forming units of each bacterial strain ≥ 108 CFU/g; enzyme activity of each enzyme ≥ 200 U/g); or 3) mixed bacterial inoculants containing Lactobacillus plantarum, Bacillus subtilis, and Aspergillus oryzae (T2, viable colony-forming units of each bacterial strain ≥ 107 CFU/g). Silages were fed to eighteen Holstein bull calves (n =6/treatment) weighing 163.83±7.13 kg to determine intake in a 49-day experimental period. The results showed that beef cattle fed T1 silage or T2 silage had a significantly higher (P < 0.05) average daily gain (ADG) than those fed CK silage, but the difference in dry matter intake was not significant (P > 0.05). The apparent digestibility of CP and ADF were higher (P < 0.05) for beef cattle fed T1 silage or T2 silage than for those fed CK silage. The rumen bacterial community of beef cattle fed T1 silage or T2 silage had a tendency to increase (P > 0.05) abundance of Firmicutes and of Rikenellaceae_RC9_gut_group than those fed CK silage. Rumen fungal communities of beef cattle fed T1 or T2 silage had a tendency to increase (P > 0.05) abundance of Mortierellomycota and of Mortierella than those fed CK silage. Spearman’s rank correlation coefficient showed that the apparent digestibility of ADF for beef cattle was positively correlated with unclassified_p_Ascomycota of the fungal genera (P < 0.05). Neocalimastigomycota of the fungal phyla was strongly positively correlated with the apparent digestibility of NDF (P < 0.05). Ruminococcus was positively correlated with the apparent digestibility of CP (P < 0.05). It was concluded that both T1 and T2 improved the growth performance of beef cattle by improving the ruminal apparent digestibility of CP and ADF, and had no significant impact on major rumen microbial communities in beef cattle.

Thymol improves the growth performance of blue foxes by regulating the gut microbiota

“…A decrease in apparent digestibility leads to nutrient loss and affects the production profits of farmers ( Liu et al, 2023 ). An increase in apparent digestibility can lead to an increase in the growth performance of beef cattle ( Tang et al, 2023 ). Thymol, a healthy and green plant essential oil extract that does not cause potential side effects on the body, has been used as a food preservative, insect repellent and anti-inflammatory drug ( Luo et al, 2020 ).…”