In vitro evaluation of agro-industrial by-products as alternative feed sources for guinea pigs (Cavia porcellus)

The guinea pig (Cavia porcellus) is a fiber-adapted herbivorous rodent with a particular digestive system based on cecal fermentation to maximize nutrient utilization. However, Knowledge regarding the nutritional requirements of guinea pigs and the evaluation of feedstuffs remains limited. This study assessed the in vitro digestibility of agroindustrial by-products as alternative feed sources for guinea pigs, using a three-phase digestion model simulating gastric, intestinal, and cecal fermentation. Agro-industrial by-products from horticultural sources (broccoli and cabbage) and agricultural sources (corn husk and sugarcane bagasse), as well as a conventional guinea pigs diet, were evaluated. Chemical composition, in vitro dry matter digestibility, and gas production throughout cecal fermentation were determined. Significant differences in chemical composition were observed among the tested by-products. Horticultural wastes showed lower fiber and higher crude protein content (19.7 - 22.3 %) compared to agricultural by-products (1.76 - 5.08 %, P < 0.05). In vitro dry matter digestibility was higher (67 - 73 %, P < 0.05) in horticultural by-products, whereas gas production was lower in corn husk and sugarcane bagasse (253 -290 mL/g of DM), exhibiting lower fermentative activity. In conclusion, agro-industrial by-products represent a feasible nutritional alternative for guinea pigs, and horticultural residues demonstrating superior digestibility and fermentative potential (574 - 587 mL/g of DM). These findings support the development of more sustainable and cost-effective feeding strategies for guinea pig production, while also providing a non-invasive alternative that eliminates the need for animal slaughter.