Effects of feeding agroindustrial byproducts on rumen fermentation and microbiome of sheep

The use of agroindustrial byproducts in ruminant nutrition is gaining increased attention because of economic and environmental benefits and their potential to enhance ruminal function and animal performance. However, the effect of these byproducts on ruminal microbiome and fermentation has been scarcely investigated. This study aimed to evaluate the effects of replacing conventional feeds with agroindustrial byproducts (18:18:8 mixture of corn dried distillers grains with solubles, dry citrus pulp, and exhausted olive cake) on the ruminal microbiome and fermentation parameters of sheep. Four rumen-fistulated Lacaune sheep were used in 2 experimental periods, receiving mixed diets composed of 50% alfalfa hay and 50% of either a control concentrate (CON diet) or a concentrate with agroindustrial byproducts (BYP diet). Ruminal samples were collected at 0, 3, and 6 h postfeeding to assess microbial composition and fermentation parameters. Diet significantly influenced the ruminal microbiome, but the effect of individual sheep was more pronounced than that of the diet. Sampling time also influenced the ruminal microbiome. The inclusion of agroindustrial byproducts in the concentrate did not significantly alter ruminal fermentation parameters. However, the BYP diet led to more steady ruminal fermentation, preventing large fluctuations in total VFA and ammonia concentrations, likely the result of a broader range of fermentable substrates present in the BYP concentrate and changes in ruminal microbiome. These results may indicate improved synchronization of nutrient availability for ruminal microorganisms. Overall, replacing conventional feed ingredients with agroindustrial byproducts promoted microbial diversity and improved ruminal fermentation, potentially leading to increased dairy ruminant performance.