Preservation of hatchery waste by lactic acid fermentation. 1. Laboratory scale fermentation

Abstract

In Experiment 1, two types of hatchery wastes, including cockerel chicks (CC), and shell waste (SW) blended with CC (60:40 CC:SW), were ground and mixed with a by-product carbohydrate (5, 10, and 15% wt/wt) with or without a bacterial culture and fermented for a period of 21 d. Cockerel chicks fermented with 15% carbohydrate and the culture had a pleasant smell and little H2S production. Elevated H2S concentrations were recorded for CC:SW samples at all carbohydrate levels when the culture was not added. No NH3 was detected from any treatments during fermentation. The addition of culture to the CC and CC:SW by-products resulted in pH values lower (P < 0.05) than those without culture on Day 21, and the 15% carbohydrate treatment significantly reduced pH beyond the 5% carbohydrate. Final proximate composition of CC and CC:SW samples with culture were not significantly different from those without culture added. In Experiment 2, carbohydrate was added at 10.0, 13.3, 16.7, and 20.0% wt/wt to CC and CC:SW in the presence of the bacterial culture. Shell waste alone was fermented with 15, 20, and 25% carbohydrate and the culture. Moisture level in this experiment was adjusted to approximately 70% for all treatments. The lowest pH for the CC and CC:SW treatments was observed at the 16.7% carbohydrate level. Shell waste pH was better maintained at the 20 and 25% carbohydrate levels. After fermentation for 21 d CC, CC:SW and SW treatments from Experiments 1 and 2 contained negligible Escherichia coli, and no Salmonella were detected.