Potential alternative feed sources for ruminant feeding from the biodiesel production chain by-products

This study aimed to evaluate the chemical composition, fractionation of nitrogen compounds and carbohydrates, digestibility parameters, gas production kinetics and ruminal fermentation of fruit seed cakes. The experiment was conducted in a completely randomized design with three fruit seed cakes (treatments) and four replications. The cakes were made of seeds of custard apple (Annona squamosa), soursop (Annona muricata) and passion fruit (Passiflora edulis), which were collected in a biodiesel plant. The passion fruit seed cake presented the highest content of dry matter, neutral detergent fibre crude protein (NDFcp), acid detergent fibre (ADF), lignin and total carbohydrates (P<0.05). The custard apple seed cake presented high proportions of crude protein, condensed tannins and digestible energy (P<0.05). The soursop seed cake presented higher values for ether extract and total digestible nutrients (P<0.05). For potential degradability, the authors detected a difference between the custard apple, soursop and passion fruit seed cakes. The total volume of gases was higher for custard apple and soursop seed cakes. Custard apple seed cake presented higher proportions of in vitro degradation parameters (P<0.05). Thus this cake could provide greater nutrient levels when supplied in ruminant diets, followed by soursop seed cake and passion fruit seed cake. Keywords: alternative food, by-products, ruminant feeding, seed cake, semi-ari