Utilization of Solid Wastes from Tanneries as Possible Protein Source for Feed Applications: Acute and Sub-acute Toxicological Studies to Assess Safety of Products Prepared from Delimed Tannery Fleshings

Abstract

Purpose Delimed tannery fleshing (DTF) hydrolysates— obtained through acid hydrolysis and fermentation—have the potential for use in poultry and fish feed owing to their protein content and inherent biofunctionalities like antioxidant and antibacterial properties. The objective was to establish the safety of DTF hydrolysates for a possible use as feed supplement. Methods Weanling male Wistar rats were fed with a dose of 5, 10 and 15 % of acid hydrolyzed DTF (AH), fermented DTF (FH) and DTF. The test animals were monitored for signs of toxicity for a period of 15 days in acute toxicity studies; while, for the sub-acute studies, rats were fed with 15 % AH, FH and DTF for 30 days. In both cases, rats were not adversely affected by the diet containing DTF hydrolysates or DTF. The feed intake, body and organ weights of the test diet fed rats were comparable to that of the control group. Result Further, therewere no significant (P[0.05) changes in biochemical parameters of serum, liver and urine samples analysed from all the groups. The histology of liver revealed no changes among all the groups as compared to control. Conclusions The present study showed that DTF/DTF hydrolysates can be supplemented in diets up to 15 % without inducing any toxicity related changes; and, emphasizes the scope of a novel form of protein based feed ingredient. Our study gives the path forward for developing livestock feeds containing DTF and DTF hydrolysates as one of the ingredients.