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

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.