Chemical characterization, dry matter and crude protein ruminal degradability and in vitro intestinal digestion of acid and fermented silage from tilapia filleting residue

The objective of the present study was to evaluate the chemical characteristics, amino acids and fatty acids profiles, dry matter (DM) and crude protein (CP) ruminal degradability and rumen-undegraded protein digestible in the intestine (RUPD) of the tilapia filleting residue (TFR) and of the acid and fermented silage of tilapia filleting residue (ASTFR and FSTFR, respectively). The ASTFR was obtained by an acidification process with the addition of 0.02 L/kg TFR of sulfuric acid and 0.02 L/kg TFR of formic acid and the FSTFR was obtained by fermentation with the addition of 0.05 kg/kg TFR of natural yogurt, 0.15 kg/kg TFR of molasses and 0.003 kg/kg TFR of sorbic acid. A completely randomized design was used to characterize the fatty acids profile of the ASTFR and FSTFR and to determine ruminal degradability of DM and CP of ASTFR, FSTFR and fishmeal (FIME). The amino acids profiles of the ASTFR and FSTFR differed from TFR, but ASTFR and FSTFR were similar to each other. The fatty acids profiles of the ASTFR and FSTFR were similar to the TFR profile. The ASTFR showed a higher (P<0.05) saturated fatty acid content in comparison to the FSTFR. The effective degradability (ED) of the CP at solid passage rate of 0.05 h−1 of the ASTFR and FSTFR were of 0.76 and 0.81, respectively, which are higher (P<0.05) than the TFR value of 0.44. To the ASTFR and FSTFR lower values (P<0.05) were observed to RUPD of 13.5 and 18.8 g/kg, respectively, in comparison the FIME of 224.4 g/kg RUP. The ASTRF and FSTRF showed alteration composition chemical and amino acids profile without altered the nutritive value of TFR. The processes of acidification or fermentation are methodologies that can be used as a conservation procedure of tilapia filleting residue.