Utilization of Avocado and Mango Fruit Wastes in Multi-Nutrient Blocks for Goats Feeding: In Vitro Evaluation

SIMPLE SUMMARY: The demand for animal products generated with high animal welfare standards and low environmental impact is continuously increasing. Moreover, the growing awareness of consumers about the importance of a healthy diet to reduce the prevalence of dietary illnesses has increased the consumption of vegetables and fruits, generating more vegetable wastes. Using these wastes in animal feeding would reduce the pollution caused by their accumulation, but their nutritive value needs to be assessed. We analyzed the chemical composition and in vitro ruminal fermentation of avocado and mango fruit wastes (peels and a pulp:peels (PP) mixture), and the potential of including the PP mixture into multi-nutrient blocks (MB) for goats feeding. Tested wastes had high-moisture content, but whereas those from mango were rich in non-structural carbohydrates, those from avocado had high fat content. Mango wastes were fermented at a greater extent and faster rate than avocado ones. Only subtle differences were observed in the fermentation of MB including PP from either avocado or mango. Using the PP mixture in MB for goats seems to be a viable solution to reduce the waste’s environmental impact, but studies assessing the MB acceptance by the animals and their stability over long-time storage periods are needed. ABSTRACT: This study was conducted to investigate the nutritive value of avocado and mango fruit wastes, and to assess the possibility of preserving the wastes into multi-nutrient blocks (MB). Both peels and a pulp:peels (PP) mixture of each fruit were analyzed for chemical composition and in vitro fermentation with goats’ ruminal fluid. Wastes had low-dry matter (DM) content (<250 g/kg), with those from mango having high non-structural carbohydrates content (>800 g/kg DM) and those from avocado high fat levels (>580 g/kg DM). Mango wastes were fermented at a greater extent and faster rate than avocado ones. The PP mixture of each fruit was included into multi-nutrient blocks (MB) formulated to have similar chemical composition. There were only subtle differences in the fermentation of MB including wastes from either avocado or mango, but fermentation of avocado-MB resulted in significantly (p ≤ 0.032) greater acetate and lower propionate proportions than mango-MB. Including the PP mixture in the formulation of MB for goats feeding is a feasible option to reduce the environmental impact of avocado and mango fruit wastes, but studies on the acceptance of the MB by goats and their stability over long-time storage periods are needed.