Nutritional composition and in vitro fermentation of avocado fruit fractions from different varieties

Abstract

<p><strong>Background:</strong> The rising feed shortages in livestock production have increased interest in exploring alternative resources. Avocado by-products, often discarded, may serve as a nutrient-rich and sustainable feed option for ruminants. <strong>Objective:</strong> To evaluate the chemical composition, mineral content, <em>in vitro</em> dry matter digestibility (IVDMD), and <em>in vitro</em> gas production of morphological fractions of ripe fruits from seven avocado varieties (Bacon, Ettinger, Fuerte, Hass, Local, Nabal, and Pinkerton) grown in the Wondo Genet district, Sidama region, Ethiopia. <strong>Methodology:</strong> Chemical analyses were conducted using Near-Infrared Reflectance Spectroscopy, and mineral analyses were conducted using Atomic Absorption Spectroscopy, while <em>in vitro</em> gas production was measured following the Menke and Steingass protocol using sheep rumen fluid. Statistical analysis was carried out using the Proc Mixed procedure in SAS software (version 9.4). <strong>Results:</strong> The results revealed significant effects (<em>P</em> < 0.0001) of variety and morphological fraction on all measured parameters. The Nabal variety had the highest fruit, pulp, seed, and peel weights. Seeds showed the highest dry matter and <em>in vitro</em> dry matter digestibility, while pulp fraction had the highest ether extract and crude protein contents. Pinkerton and local varieties had the highest protein content, whereas coat was richest in neutral detergent fiber (NDF) and acid detergent fiber (ADF). Peel fractions exhibited high ADL. The highest calcium content was found in the Fuerte variety and coat fraction, while the Pinkerton variety and pulp fraction had the highest phosphorus content. Significant differences were also observed in gas production kinetics, metabolizable energy (ME), organic matter digestibility (OMD), and short-chain fatty acid (SCFA) production. Local variety and seed fraction exhibited the highest IVDMD and SCFA, while pulp fraction had the highest ME contents. <strong>Implications:</strong> Avocado fruit by-products, especially pulp and seed, can serve as alternative ruminant feed resources, supporting sustainable livestock production and reducing agro-industrial waste; however, appropriate processing and preservation strategies are required to overcome limitations associated with long-term storage. <strong>Conclusion:</strong> Avocado fruit waste has high crude protein, ether extract, digestibility, and energy values, with significant variation across varieties and fractions, indicating their nutritional potential in ruminant feeding when suitable storage and handling practices are applied.</p>