Peruvian maca supplementation improves growth efficiency and modulates gut microbiota in pigs without affecting meat quality

Plant-derived additives in animal nutrition are frequently studied for their potential to enhance growth performance and meat quality. Their effects on gut microbiota composition are also evaluated in view of its fundamental role in overall animal health and metabolic homeostasis. Therefore, we investigated the effect of adding Peruvian maca ( Lepidium meyenii ) to the pig diet on pH, ammonia, and short chain fatty acids ( SCFA ) in the digesta and growth parameters, carcass characteristics, and gut microbiota in growing pigs using next generation sequencing ( NGS ). The experiment included two dietary treatments: the control (Con group), a diet without maca additive, and a Maca (maca group) diet supplemented with 1% of dried powdered roots of Peruvian maca. A total of forty gilts with an average body weight of 29 kg were equally divided into two groups and fed the experimental diets for 108 days, a period that was divided into two phases (Period 1 and Period 2). Maca supplementation did not affect growth performance during Period 1. In contrast, during Period 2 pigs receiving the maca-supplemented diet exhibited a higher average daily weight gain compared to the control group. Descriptive evaluation of pen-based production data indicated a trend towards improved feed conversion ratio, while daily feed intake remained comparable between the dietary treatments. Across the whole fattening period, maca-fed pigs maintained better growth efficiency and a lower liver-to-body weight ratio. Carcass traits were generally unaffected, with the exception of a reduced liver-to-carcass ratio in the maca group. Meat quality parameters were largely unchanged; only pH measured 24 h post mortem was significantly lower, while proximate composition and technological traits (e.g., drip loss, tenderness, water-holding capacity) remained unaffected. Statistical analysis demonstrated a significantly lower ileal pH in the maca group, suggesting a more acidic intestinal environment, whereas ammonia concentration and SCFA profiles showed no differences. Blood biochemistry indicated higher serum glucose levels in pigs fed maca. Maca supplementation affected gut pH and microbiota, suggesting potential benefits for intestinal health by increasing Lactobacillus abundance and decreasing abundance of Campylobacter , thus supporting animal welfare and sustainable production. Bioactive plant compounds appear promising as supplements, but more research is needed on their dosage and long-term effects.