The influence of lupin seed germination on the chemical composition and standardized ileal digestibility of protein and amino acids in pigs

Abstract

The germination process can modify the chemical composition of nutrients in seeds, which can influence the digestibility and utilization of sprouts in animal diets compared to raw seeds. The aims of research were to provide controlled germination process of lupin seeds, monitor the changes in seed composition and determine the influence of the germination on the coefficients of standardized ileal digestibility (SID) of crude protein and amino acids in growing pigs, compared to raw lupin seeds. The seeds of two lupin species were used: yellow (RYL) (Lupinus luteus, cv. Lord) and blue (RBL) (Lupinus angustifolius, cv. Graf). Germination was provided in the dark at 24°C for 4 days. Nutritional and antinutritional compositions of raw and germinated seeds (GYL and GBL, respectively) were analysed. Digestibility study was performed on pigs with an average body weight of 25 kg, and the pigs were surgically fitted with a T-cannula in the distal ileum, with chromic oxide as an indicator. Seed germination increased the crude protein and fibre concentrations, but reduced the levels of the ether extract, nitrogen-free extracts and all amino acids in protein. The content of alkaloids and raffinose family oligosaccharides decreased in both lupin species. Germination had no positive impact (p>0.05) on the SID of crude protein and amino acids. Germination of lupin seeds negatively influenced the SID of lysine and methionine (p<0.05). The results of the research revealed a decrease in the concentrations of antinutritional factors in the sprouts of yellow and blue lupins compared to raw seeds; however, no positive effect was observed on the coefficients of the standardized ileal apparent digestibility of protein and amino acids.