Epsilon Archive for Student Projects

Abstract

The study aimed to evaluate the protein and amino acid digestibility of press juice from biorefined ley crops in the form of fresh (FPJ) and silage (SPJ) when included as an ingredient in liquid diets for pigs. The juice was extruded from ley crops mixture (grass-clover). The juice was stored in 10 L plastic containers and frozen at -20° C until the day of use. Eight female pigs (YH) around 9 weeks of age and an average of 24.15 (+2.76) kg BW were randomly assigned to one of the two dietary treatments containing FPJ (n = 4) or SPJ (n = 4). The diets were formulated to meet the nutritional requirements of the pigs, based on 4% of the average BW with the inclusion of 50 % of press juice in the mixture on a dry matter (DM) basis. The dietary treatments were mixed with a protein-free basal diet with an indigestible marker of titanium dioxide (TiO2) in order to calculate the protein and amino acid digestibility. The experimental period lasted for eleven days with seven days for adaptation to the diet and four days of faecal sampling. At the end of the trial the animals were euthanized, and the ileal content was collected for analyses of crude protein, amino acids, and concentration of TiO2. The differentiation of the indigestible marker obtain in the samples were used to calculate the apparent total tract digestibility (ATTD), apparent ileal digestibility (AID) and standardized ileal digestibility (SID) values of crude protein and amino acids for press juice in both fresh and silage form. A statistical general linear model (PROC GLM) was used to analyze the digestibility values between the two dietary treatments. The results of the trial showed that there was no significant difference (p>0.05) for gaining weight in pigs fed with FPJ or SPJ diets. The ATTD of crude protein (CP) and organic matter (OM) were higher (p<0.05) for the SPJ diet and the values for AID of CP, lysine, and threonine were unaffected by treatment, however, the values for AID of methionine were higher (p<0.05) for the SPJ diet. The SID of lysine and methionine was higher (p<0.05) for SPJ than FPJ diet, and despite the fact that SID of CP and threonine were higher for SPJ there was not significant difference (p>0.05). In conclusion, the acceptable levels of protein and amino acid digestibility of both FPJ and SPJ evaluated in growing pigs opens the potential to use the protein content found in these biorefinery fractions as an additional protein source to be considered in the inclusion of liquid diets for pigs.